Class Discussion Topics (2019 odd semester):
Students are invited to post information relevant to the MMV course here, in relation to class discussion. Let us start with:
What are the challenges in correlating composition of the human microbiome with any particular disease and/or overall health status of individuals?
QTS: In pre-antibiotic era there was occurence of resistant organisms , why?
ReplyDeleteANS: The possibility of exposure to antimicrobials in the pre-antibiotic era could be reason of occurence of resistant organisms.
~The natural history of antibiotic resistance genes can be revealed through the phylogenetic reconstruction.Structure-based phylogeny of serine and metallo-β-lactamases, showed that these ancient enzymes originated more than two billion years ago. some serine β-lactamases being present on plasmids for millions of years confers resistant character to some microorganisms.The similar phylogenetic analysis of β-lactamases in the metagenomic clones derived from the 10,000 years old “cold-seep” sediments indicated that most of the diversity of these enzymes is not the result of recent evolution, but is that of ancient evolution .
~Genes linked to antibiotic resistance have been found in the Pre-Columbian mummy’s colon. These gene mutations occurred naturally, long before the introduction of modern medical antibiotics.
~The traces of tetracycline, have been found in human skeletal remains from ancient Sudanese Nubia dating back to 350–550 CE . The distribution of tetracycline in bones is only explicable after exposure to tetracycline-containing materials in the diet of these ancient people.
This all suggests that genes responsible for resistant towards antibiotics have been ancient evolution even before the antibiotics were discoverd.
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ReplyDeleteQ. List of priority microorganisms by WHO?
ReplyDeleteA. Priority 1 critical
Acinetobacter baumannii, carbapenem-resistant
Pseudomonas aeruginosa, carbapenem-resistant
Enterobacteriaceae, carbapenem-resistant, ESBL-producing
Priority 2: High
Enterococcus faecium, vancomycin-resistant
Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant
Helicobacter pylori, clarithromycin-resistant
Campylobacter spp., fluoroquinolone-resistant
Salmonellae, fluoroquinolone-resistant
Neisseria gonorrhoeae, cephalosporin-resistant,
fluoroquinolone-resistant
Priority 3: Medium
Streptococcus pneumoniae, penicillin-non-susceptible
Haemophilus influenzae, ampicillin-resistant
Shigella spp., fluoroquinolone-resistant
Riboswitch: a regulatory segment of messenger RNA molecule that binds a small molecule resulting in a change in production of the proteins encoded by the mRNA.
ReplyDeleteSiderophore: are small, high-affinity iron-chelating compounds secreted by microorganisms and serving to transport iron across cell membranes.
Riboswitches
ReplyDeleteIn 2002, Ronald Breaker, Henry Ford II professor and incoming department chair of Molecular, Cellular, and Developmental Biology, discovered riboswitches, which are portions of RNA that bind to DNA and control the activity of genes.
Riboswitches are most often located in the 5' untranslated region (5' UTR; a stretch of RNA that precedes the translation start site) of bacterial mRNA. There they regulate the occlusion of signals for transcription attenuation or translation initiation.
Riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA.
Riboswitches could be a target for novel antibiotics. Indeed, some antibiotics whose mechanism of action was unknown for decades have been shown to operate by targeting riboswitches. Riboswitches are an effective method of controlling gene expression in natural organisms.
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Problems in Drug Discovery
ReplyDelete1). Drug discovery is a lengthy, complex, and costly process, entrenched with a high degree of uncertainty that a drug will actually succeed.
2).Translational Failures Using Animal Models
3).There is a lack of validated diagnostic and therapeutic biomarkers to objectively detect and measure biological states.
4).Inability to Rely on Published Data
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Riboswitches
ReplyDeleteA riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA.
Life in a RNA world would have relied on RNA as both a medium for heritable genetic information and chemical catalysis.
One of the most striking recent examples of how RNA regulates gene expression was revealed by the discovery of riboswitches a common means of genetic regulation at the mRNA level in the bacterial kingdom.
The typical riboswitch contains two distinct functional domains. A) The effector molecule is recognized by an aptamer domain, which adopts a compact three _ dimensional fold to scaffold the ligand binding pocket. As with proteins these RNA receptors must discriminative between chemically related metabolites with high selectivity to elicit the appropriate regulatory response. B) a second domain the expression platform, contain a secondary structural switch that interfaces with transcriptional or translation machinery. Regulation is achieved by virtue of a region of overlap between these two domains, known as the switching sequence, whose pairing directs folding of the RNA into one of two mutually exclusive structures in the expression platform that represent the on and off states of the mRNA.
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Riboswitches:
ReplyDeleteA ribo-switch is a cis- regulatory RNA element that regulates expression of a downstream or upstream Gene in response to a specific ligand molecule.
Riboswitches are structured RNA regulatory elements located in 5' UTRs of mRNA. Since they do not require protein for their functions, they are ideally suited for computational analysis using the toolbox of RNA structure prediction methods.
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Q) Enlist the diferent classes of antifungal with their mode of
ReplyDeleteaction.
Ans. Antifungals can be grouped into three classes based on their
site of action:
1)Azoles: inhibit the synthesis of ergosterol (the main fungal
sterol);
The azoles constitute imidazoles and triazoles subgroups and act by inhibiting CYP P450 14 α- demethylase enzyme in fungi which causes the conversion of lanosterol to ergosterol. Other P450s in sterol biosynthesis may also be affected.
The nitrogen of the azole ring forms a bond with the heme iron of the fungal P450 preventing substrate and oxygen binding, leading to changes in shape and physical properties of the fungi membrane, leading to permeability and fluidity changes.
2)Polyenes: interact with fungal membrane sterols
physicochemically;
The polyene antibiotics cause permeability alterations which lead to the loss of essential cytoplasmic constituents culminating in cell death.
the interaction of the antifungal with membrane sterol results in the production of aqueous pores consisting of an annulus of eight amphotericin B molecules linked hydrophobically to the membrane sterols. This configuration gives rise to a pore in which the polyene hydroxyl residues face inward, leading to altered permeability, leakage of vital cytoplasmic components, and death of the organism.
3)5-fluorocytosine: inhibits macromolecular synthesis.
5FC enters fungal cells aided by a permease enzyme. It is converted to 5-fluorouracil (5FU) by the enzyme cytosine deaminase. Subsequently, 5FU is converted by UMP pyrophosphorylase into 5-fluorouridylic acid (FUMP), which is phosphorylated further and incorporated into RNA, resulting in disruption of protein synthesis. 5FU also is converted to 5-fluorodeoxyuridine monophosphate, a potent inhibitor of thymidylate synthase, an enzyme involved in DNA synthesis and nuclear division.
Thus, 5FC acts by interfering with pyrimidine metabolism, as well as RNA, DNA, and protein synthesis in the fungal cell.
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DeleteDifferent class of antifungal agents and it's mode of action.
ReplyDelete(1) Polyene
Drugs like Amphotericin, Nystatin and Pimaricin interact with sterols in the cell membrane (ergosterol in fungi, cholesterol in humans) to form channels through which small molecules leak from the inside of the fungal cell to outside.
(2) Azole
Drugs like Fluconazole,Itraconazole and Ketoconazole inhibit Cytochrome P450 dependent enzymes (demethylase) involved in the biosynthesis of ergosterol which is required for fungal cell membrane structure and function.
(3) Allylamine & Morpholine
Inhibit ergosterol biosynthesis at the level of Squalene epoxidase.
(4) Antimetabolite antifungal drugs
5-fluorocytosine acts as an inhibitor of both DNA and RNA synthesis.
(5) Echinocandin
Caspofungin impairs B1,3 glucan synthesis.
(6)Nucleoside analog
Flucytosine impairs pyrimidine metabolism.
-Other Antifungal agents
Griseofulvin is antifungal antibiotic produced by P.griseofulvum.it inhibit mitosis in fungi.
Ideal characteristics of an Antibiotic.
ReplyDelete(1) selectively toxic to the microbes but nontoxic to host cells.
(2) stay in target tissues for a long time to be effective.
(3) cause no allergic reaction in the host.
(4) it should be stable at gastric ph.
(5) it should have plasma stability.
(6) Be stable when stored in solid or liquid form.
(7) Remains potent long enough to act and is not broken down or excreted prematurely.
(8) Readily delivered to the site of infection.
(9) Relatively soluble, function even when highly diluted in body fluid.
(10) Reasonably priced.
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ReplyDeleteQ:Different class of antifungal agents and it's mode of action
A: Allylamines.
✳️ Mechanism of action
Allylamines: such as
terbinafine and naftifine, have been developed as a new class of
ergosterol biosynthetic inhibitors that are functionally as well
as chemically distinct from the other major classes of ergosterol-inhibiting antifungal agents..
Terbinafine : is highly effective against dermatophytes in vivo and in vitro.
▪️Inhibitors of glucan synthesis
aculeacins, echinocandins, and papulacandins
are specific inhibitors of fungal 3b-glucan synthase, only echinocandins are being actively pursued in clinical trials to
evaluate their safety, tolerability, and efficacy against candidioasis. Echinocandins, which are lipopeptides, have fungicidal
activity both in vitro and in vivo against Candida and Aspergillus.
✳️Mechanism of action. b-Glucan inhibitors act as specific
noncompetitive inhibitors of b-(1,3)-glucan synthetase, a large
integral membrane heterodimeric protein.
Treatment of fungi with the compounds inhibits the synthesis
of the structural glucan component without affecting nucleic
acid or membrane synthesis . Inhibitors of glucan synthesis also have secondary effects on other components of
intact cells including a reduction in the ergosterol and lanosterol content and an increase in the chitin content of the cell
wall . Inhibition of b-(1,3)-glucan synthetase results in
cytological and ultrastructural changes in fungi characterized
by growth as pseudohyphae, thickened cell wall, and buds
failing to separate from mother cells.
▪️5-Fluorocytosine ( Compounds Inhibiting Nucleic Acids)
✳️Mechanism of action. 5FC is a fluorinated pyrimidine with inhibitory activity against many yeasts.
▪️amphotericin B
✳️Mechanism of action : it has been
proposed that the interaction of the antifungal with membrane
sterol results in the production of aqueous pores consisting of
an annulus of eight amphotericin B molecules linked hydrophobically to the membrane sterols .This
configuration gives rise to a pore in which the polyene hydroxyl
residues face inward, leading to altered permeability, leakage
of vital cytoplasmic components, and death of the organism
Question : Classes of antifungal and their mode of action.
ReplyDeleteAns.
1. Polyene antibiotics:-
Nystatin : It binds to fungal cell membrane and forms pores.This alters permeability & transport and as a result, cell death occurs.
2. Heterocyclic benzofuran:-
Griseofulvin : It is fungistatic in nature.It interferes with mitosis-multinucleated and stunned fungal hyphae result from its action.
3. Antimetabolite:-
Flucytosine : It is a pyrimidine antimetabolite and inactive as such.It disrupts nucleic acid and protein synthesis.
4. Echinocandins:-
Echinocandins interfere with the synthesis of the fungal cell wall.It is Glucan synthesis inhibitor.Disruption of the fungal cell wall leads to cellular osmotic instability and cell death.
5. Terbinafine:-
It interferes with ergosterol biosynthesis by inhibiting the fungal enzyme squalene epoxidase . Acting as a structural analogue of squalene, terbinafine causes the accumulation of this unsaturated hydrocarbon, and a decrease in ergosterol in the fungal cell membrane.
The accumulation of toxic amounts of squalene result in the death of the fungal cell.
6. Azoles:-
The azole antifungal drugs act by inhibiting the synthesis of the sterol components of the fungal membrane. Azoles are predominantly fungistatic.
7. Topical antifungals:-
Ciclopirox : It inhibits the transport of essential elements in the fungal cell, disrupting the synthesis of DNA, RNA, and protein.
Tolnaftate: It distorts the hyphae and stunts mycelia growth in susceptible fungi.
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Riboswitches:
ReplyDeleteA riboswitch is a cis-regulatory RNA element that regulates expression of a downstream or upstream gene in response to a specific ligand molecule.The function of riboswitches is tied to the ability of RNA to form a diversity of structures. Riboswitches are most often located in the 5' untranslated region (5' UTR; a stretch of RNA that precedes the translation start site) of bacterial mRNA. There they regulate the occlusion of signals for transcription attenuation or translation initiation. However, not all riboswitches are at the 5' UTR, in some eukaryotic mRNA, the thiamine pyrophosphate (TPP) riboswitch regulates splicing at the 3' end. The drugs designed to inhibit riboswitches have minimal side effects in humans because riboswitches have not been identified in mammals, so they are not likely to act on mammalian mRNA and some riboswitches are known to bind their cognate ligand in fundamentally different ways than do mammalian proteins that recognize the same ligand this means there is reason to suspect they won't interfere with ligand binding in native mammalian systems.
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Siderophores:
ReplyDeleteIron is an essential nutrient for the host as well as for most microbes. In the host, free iron levels are extremely low, as the metal is largely bound to proteins, and iron is further limited during infection through a process known as nutritional immunity. To overcome nutritional immunity, some bacteria and fungi produce siderophores, which are small molecules that chelate iron. Siderophores are small molecular iron chelators that are produced by microbes and whose most notable function is to sequester iron from the host and provide this essential metal nutrient to microbes. Enterobactin (also known as enterochelin) is a catecholate siderophore produced by both commensal and pathogenic Enterobacteriaceae and has greater affinity for iron than host molecules, such as transferrin and lactoferrin. Recent studies have proposed additional, noncanonical roles for siderophores, including the acquisition of noniron metals and modulation of host functions.
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Siderophores
ReplyDeleteAny of a group of low molecular weight compounds produced especially by various microorganisms that bind ferric iron extracellularly to form a stable chelate for transport into the cell.
Riboswitches
Riboswitches are regulatory sequences in RNA molecules.
At Riboswitches, regulatory molecules bind and influence gene expression by affecting the formation of secondary structures within the mRNA molecule.
The binding of regulatory molecule to a riboswitch sequence may result in repression or induction.
Some regulatory molecules bind the riboswitch sequence and stabilize a termination structure in the mRNA, which results in premature termination of the mRNA molecule.
Other resulting in the formation of secondary structures that block ribosome binding sites of the mRNA molecule,so preventing translation initiation.
Ideal characteristics of an Antibiotics
ReplyDelete1. Broad spectrum - should be active against a wide range of pathogens.
2. selective toxicity - should act only against target not the host organism.
3. should be reasonably priced
4. should be stable when stored in solid or liquid form
5. effect should be bacteriocidial rather then bacteriostatic
6. should be stable to plasma , other body fluids and gastric ph
7. should not be cause allergic reactions in host
8. desired levels of antibiotic should reach the site of infection
rapidly and maintained for adequate period of time.
9. should be soluble in body fluids and possible to achieve concentrations in tissue or blood which are sufficiently high to kill or inhibit infectious agent
10. should not affect the normal microflora of body
10.
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DeleteIdeal characteristics of antibiotics
ReplyDelete1) they should possess a broad spectrum of antimicrobial activity at a low concentration.
2) The substance should be stable at room temperature.
3) Does not lead to development of antimicrobial resistance easily.
4) should be delivered to the site of infection in adequate concentration.
5) should be available in large amount and at reasonable price.
6) should have selective toxicity towards pathogen without exerting negative effect on host as well as normal flora of body.
7) should be relatively solube and should able to function when highly diluted in body fluids.
8) Bactericidal rather than bacteriostatic.
9) should have low MIC value.
10)should have low cost of production.
Classes of Antifungal agents and their mode of action
ReplyDelete1. Polyene
AMPHOTERICIN B, NYSTATIN, NATAMYCIN
Mechanism of Action: Binds to ergosterol in fungal membrane causing membrane to become leaky.
2. Azoles and Triazole Antifungal Agents
Mode of Action - The azoles, imidazoles and triazoles inhibit CYP P450 14 α- demethylase in fungi. This enzyme is involved in the conversion of lanosterol to ergosterol.
3. Allylamines
Mechanism of Action: These antifungal agents are reversible, noncompetitive inhibitors of the first step in ergosterol biosynthesis, the conversion of squalene to squalene-2,3-epoxide by squalene epoxidase. The buildup of squalene in the cell membrane is toxic to the cell,causing pH imbalances and malfunction of membrane bound proteins.
4. Topical antifungals
CICLOPIROX
mode of action: Ciclopirox inhibits the transport of essential elements in the fungal cell, disrupting the synthesis of DNA, RNA, and protein.
5.Echinocandins
mode of action : Echinocandins interfere with the synthesis of the fungal cell wall. It is Glucan synthesis inhibitor, nhibits 1,3- beta glucan synthase, an enzyme important in fungal cell wall synthesis and subsequently inhibit the synthesis of beta glucan in the fungal cell wall. Disruption of the fungal cell wall leads to cellular osmotic instability and cell death.
6. Antimetabolite
FLUCYTOSIN
mode of action - It is a pyrimidine antimetabolite and inactive as such.It disrupts nucleic acid and protein synthesis.
7. Heterocyclic benzofuran:-
GRISEOFULVIN
mode of action : It is fungistatic in nature.It interferes with mitosis-multinucleated and stunned fungal hyphae result from its action.
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>>List of priority pathogens by WHO
ReplyDelete*Priority 1: CRITICAL
Acinetobacter baumannii, carbapenem-resistant
Pseudomonas aeruginosa, carbapenem-resistant
Enterobacteriaceae, carbapenem-resistant, 3rd generation cephalosporin-resistant
*Priority 2: HIGH
Enterococcus faecium, vancomycin-resistant
Staphylococcus aureus, methicillin-resistant, vancomycin intermediate and resistant
Helicobacter pylori, clarithromycin-resistant
Campylobacter, fluoroquinolone-resistant
Salmonella spp, fluoroquinolone-resistant
Neisseria gonorrhoeae, 3rd generation cephalosporin-resistant, fluoroquinolone-resistant
*Priority 3: MEDIUM
Streptococcus pneumoniae, penicillin-non-susceptible
Haemophilus influenzae, ampicillin-resistant
Shigella spp, fluoroquinolone-resistant
>Mycobacteria (including Mycobacterium tuberculosis, the cause of human tuberculosis), was not subjected to review for inclusion in this prioritization exercise as it is already a globally established priority for which innovative new treatments are urgently needed.
>Enterobacteriaceae include: Klebsiella pneumonia, Escherichia coli, Enterobacter spp, Serratia spp, Proteus spp, and Providencia spp, Morganella spp.
Question . Ideal characteristics of Antibiotics..
ReplyDeleteAns.
The capacity of the substance to kill or inhibit microorganisms is the first requirement.
The chemical substance must be soluble in water or other solvents to the extent necessary for effective use.
It should not be necessary to raise the temperature beyond that normally found in the environment where it is to be used. It is important because, for convenience, a chemical reaction occurring at 37°C (body temp.)
The preparation of the chemical substance must be uniform in composition.
The compound must be available in large quantities at a reasonable price.
The substance should possess deodourizing ability because this ability is a desirable attribute. Ideally the disinfectant itself should either be odourless or possess a pleasant smell.
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>>Riboswitches
ReplyDeleteHow RNA regulates gene expression was revealed by the discovery of riboswitches, a common means of genetic regulation at the mRNA level in the bacterial kingdom.
Riboswitches are elements commonly found in the 5′-untranslated region (UTR) of mRNAs that exert their regulatory control over the transcript in a cis-fashion by directly binding a small molecule ligand.
Riboswitches present themselves as viable candidates for a sophisticated mechanism of regulatory control in RNA-based life. These regulatory elements in the modern world are most commonly found in the 5′-untranslated regions of bacterial mRNAs, directly interacting with metabolites as a means of regulating expression of the coding region via a secondary structural switch.
Riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA. Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule.
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ReplyDeleteQ enlist different classes of antifungal drugs and there mode of action.
ReplyDeleteAns.
a) Ally amines
Mode of action- inhibits ergosterol synthesis by inhibiting the enzyme squalene epoxidase. Eg.terbinafine
b) Antimetabolite
Mode of action- inhibits fungal protein synthesis by replacing uracil with 5fluro uracil in fungal RNA.
Inhibits thymidilate synthetase via 5-flurodeoxy-uridinemonophosphate and thus interferes with fungal DNA synthesis.
Eg.Flucytosine
c) Azoles
Mode of action-inhibition of cytochrome P450 14a-demethylase. This enzyme is in the sterol biosynthesis pathway that leads from lanosterol to ergo sterol. Eg.Ketoconaxol
d) Polyenes
Mode of action - act by binding to ergo sterol in the fungal cell membrane.this binding results in depolorization of the membrane and formation of pores that increase permeability to proteins and monovalent and divalent cations, eventually leading to cell death. Eg. Amphotericin B
e) Glucan synthesis inhibitors
Mode of actiin- blocks the synthesis of a major fungal cell wall component 1,3-beta-D-glucan. Eg. Caspofungin
f) miscellaneous
Mode of action - inhibiting fungal mitosis by disturbing the mitotic spindle through interaction with polymerized spindles. Eg. Griseofulvin
><Siderophores:
ReplyDeletesiderophores (from the Greek: “iron carriers”) are defined as relatively low molecular weight, ferric ion specific chelating agents elaborated by bacteria and fungi growing under low iron stress. The role of these compounds is to scavenge iron from the environment and to make the mineral, which is almost always essential, available to the microbial cell. Siderophores have been related to virulence mechanisms in microorganisms pathogenic to both animals and plants. In addition, they have clinical applications and are possibly important in agriculture. Siderophores are an important family of the latter type of molecules able to chelate metals, which is produced under iron-limiting conditions.
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ReplyDelete• Ideal characteristics of Antibiotic.
1)it must be act against wide range of pathogens.
2) prevent the development of resistant forms: pathogens should not easily gain resistance.
3) should be active in plasma, and other body fluids.
4) described levels should reach rapidly and maintained for adequate period of time.
5) it should remain active even when diluted in body fluids and tissues.
6) should be reasonable priced.
Different classes of antifungal agents
ReplyDeleteAntifungals are the drugs that treat fungal infections by acting on the synthesis of the fungal cell membrane, cell wall components, membrane permeability, synthesis of nucleic acids and on the mitotic spindle function of the fungi during cell division.
>>Naturally occurring:
•Antifungal Antibiotics (mostly produced by Actinomycetes, classified as ‘higher bacteria’). Examples: Amphotericin B (AMB), a polyene antimycotic, Nystatin
•Antifungals of fungal origin. Example: Griseofulvin, a Heterocyclic Benzofuran discovered in 1939 from a type of Penicillium mold
Synthetic Agents:
•Azoles
•Imidazoles: Clotrimazole, Econazole, Miconazole, Oxiconazole, Ketoconazole
•Triazoles: Fluconazole, Itraconazole, Voriconazole
•Anti-metabolites: Flucytosine (5-FC)
•Allylamine: Terbinafine (Lamisil)
•Echinocandins
>>Polyene antifungals
The polyene antimycotics bind with sterols in the fungal cell membrane, principally ergosterol. This changes the transition temperature (Tg) of the cell membrane, thereby placing the membrane in a less fluid, more crystalline state.
As a result, the cell's contents including monovalent ions (K+, Na+, H+, and Cl−), small organic molecules leak and this is regarded one of the primary ways cell dies.
•Amphotericin B
•Candicidin
•Filipin – 35 carbons, binds to cholesterol (toxic)
•Hamycin
•Natamycin – 33 carbons, binds well to ergosterol
•Nystatin
•Rimocidin
>>Imidazole, triazole, and thiazole antifungals
Azoles inhibit conversion of lanosterol to ergosterol by inhibition of lanosterol 14-alpha demethylase.
>Imidazoles
•Bifonazole
•Butoconazole
•Clotrimazole
•Econazole
•Fenticonazole
•Isoconazole
•Ketoconazole
•Luliconazole
•Miconazole
•Omoconazole
•Oxiconazole
•Sertaconazole
•Sulconazole
•Tioconazole
>Triazoles
•Albaconazole
•Efinaconazole
•Epoxiconazole
•Fluconazole
•Isavuconazole
•Itraconazole
•Posaconazole
•Propiconazole
•Ravuconazole
•Terconazole
•Voriconazole
>Thiazoles
•Abafungin
>Allylamines
Allylamines inhibit squalene epoxidase, another enzyme required for ergosterol synthesis. Examples include amorolfin, butenafine, naftifine, and terbinafine.
>Echinocandins
Echinocandins inhibit the creation of glucan in the fungal cell wall by inhibiting 1,3-Beta-glucan synthase:
•Anidulafungin
•Caspofungin
•Micafungin
Echinocandins are administered intravenously, particularly for the treatment of resistant Candida species.
>Others
•Aurones - have been shown to possess antifungal properties
•Benzoic acid – has antifungal properties, such as in Whitfield's ointment, Friar's Balsam, and Balsam of Peru.
•Ciclopirox – (ciclopirox olamine) – is a hydroxypyridone antifungal that interferes with active membrane transport, cell membrane integrity, and fungal respiratory processes. It is most useful against tinea versicolour
different classes of antifungals- based on their site of actions
ReplyDeleteClass Mechanism of action drugs
1)Allylamin Inhibits squalene epoxidase Terbinafine
2)Azole Impairs ergosterol synthesis Ketoconazole
3)Echinocandin Impairs ß 1,3 glucan synthesis Caspofungin
4)Nucleoside analog Impairs pyrimidine metabolism Flucytosine
5)Polyene Binds to ergosterol Amphotericin B
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different classes of antifungals- based on their site of actions
ReplyDeleteClass Mechanism of action drugs
1)Allylamin Inhibits squalene epoxidase Terbinafine
2)Azole Impairs ergosterol synthesis Ketoconazole
3)Echinocandin Impairs ß 1,3 glucan synthesis Caspofungin
4)Nucleoside analog Impairs pyrimidine metabolism Flucytosine
5)Polyene Binds to ergosterol Amphotericin B
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different classes of antifungals- based on their site of actions
ReplyDeleteClass Mechanism of action drugs
1)Allylamin Inhibits squalene epoxidase Terbinafine
2)Azole Impairs ergosterol synthesis Ketoconazole
3)Echinocandin Impairs ß 1,3 glucan synthesis Caspofungin
4)Nucleoside analog Impairs pyrimidine metabolism Flucytosine
5)Polyene Binds to ergosterol Amphotericin B
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Siderophores:-
ReplyDeleteSiderophores are small, high- affinity iron chelating compounds secreted by microorganisms such as bacteria and fungi and serving to transport iron across cell membranes.
Siderophore are low molecular weight iron chelating compounds synthesized by many bacteria Pseudomonas, Azotobacter, Bacillus, Enterobacter.
Siderophore forms complex with free iron and transport it into the cell by membrane receptor molecules, these molecules are encoded by five genes in operon which is turned off when sufficient iron has been taken into the cell.
At present nearly 500 siderophores are reported from selected microorganisms.
Types of siderophores:- 1) Hydroxamate siderophore. 2) catecholate siderophore.
Siderophore is biological molecule produced by various bacteria having wide application in various field such as agriculture to improve soil fertility and biocontrol, environmental application and medical application.
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Siderophores:-
ReplyDeleteSiderophores are small, high- affinity iron chelating compounds secreted by microorganisms such as bacteria and fungi and serving to transport iron across cell membranes.
Siderophore are low molecular weight iron chelating compounds synthesized by many bacteria Pseudomonas, Azotobacter, Bacillus, Enterobacter.
Siderophore forms complex with free iron and transport it into the cell by membrane receptor molecules, these molecules are encoded by five genes in operon which is turned off when sufficient iron has been taken into the cell.
At present nearly 500 siderophores are reported from selected microorganisms.
Types of siderophores:- 1) Hydroxamate siderophore. 2) catecholate siderophore.
Siderophore is biological molecule produced by various bacteria having wide application in various field such as agriculture to improve soil fertility and biocontrol, environmental application and medical application.
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Ideal characteristics of an Antibiotic:-
ReplyDelete* Selective toxic to the microbe but nontoxic to host cell.
* Relatively soluble, function even when highly diluted in body fluid.
*Remain potent long enough to act and is not broken down or excreted prematurity.
* Doesn't lead to the development of antimicrobial resistance.
* Does not disrupt the host health by causing allergies or predisposing the host to other infection.
* Reasonably priced.
* substance should be stable. Change in the substance upon standing should be minimal and should not result in significant loss of germicidal action.
* They should possess a broad spectrum of antimicrobial activity at a low concentration.
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WHO priority list of pathogen-
ReplyDeleteWHO published its first ever list of antibiotic-resistant "priority pathogens" – a catalogue of 12 families of bacteria that pose the greatest threat to human health.
The WHO list is divided into three categories according to the urgency of need for new antibiotics: critical, high and medium priority.
The most critical group of all includes multidrug resistant bacteria: Acinetobacter, Pseudomonas and various Enterobacteriaceae (including Klebsiella, E. coli, Serratia, and Proteus)They can cause severe and often deadly infections such as bloodstream infections and pneumonia.
The second and third tiers in the list – the high and medium priority categories – contain other increasingly drug-resistant bacteria that cause more common diseases such as gonorrhoea and food poisoning caused by salmonella.
CRITICAL PRIORITY ORGANISM AND ITS RESISTANCE TO THE DRUG:-
1)Acinetobacter baumannii--carbapenem-resistant
2)Pseudomonas aeruginosa--carbapenem-resistant
3)Enterobacteriaceae--carbapenem-resistant,3rd gen. cephalosporin-resistant
MEDIUM PRIORITY ORGANISMS AND ITS RESISTANCE TO TH DRUG:
1)Streptococcus pneumoniae--penicillin-non-susceptible
2)Haemophilus influenzae--ampicillin-resistant
3)Shigella species--fluoroquinolone-resistant
HIGH PRIORITY ORGANISMS AND ITS RESISTSANCE TO THE DRUG:
1)Enterococcus faecium--vancomycin-resistant
2)Helicobacter pylori--clarithromycin-resistant
3)Salmonella species--fluoroquinolone-resistant
4)Staphylococcus aureus--vancomycin-resistant,methicillin-resistant
5)Campylobacter species--fluoroquinolone-resistant
6)Neisseria gonorrhoeae--3rd gen. cephalosporin resistant,fluoroquinolone-resistant
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Q) Antimicrobial peptids : An emerging category of thraputic agent.
ReplyDeleteAns ) AMPs are evolutionary conserved in the genome and produced by all life forms, from prokaryotes to humans. In higher organisms, AMPs constitute important components of the innate immunity, protecting the host against infections. In contrast, bacteria produce AMPs in order to kill other bacteria competing for the same ecological niche.
AMPs in nature are produced either by ribosomal translation of mRNA or by nonribosomal peptide synthesis .While nonribosomally synthesized peptides are mainly produced by bacteria. The ribosomally synthesized AMPs have more recently been recognized for their critical role in innate immunity and for their therapeutic potential.
AMPs are relatively short, commonly consisting of 10–50 amino acids, display an overall positive charge ranging from +2 to +11, and contain a substantial proportion (typically 50%) of hydrophobic residues.
Many AMPs display a direct and rapid antimicrobial activity by causing disruption of the physical integrity of the microbial membrane and/or by translocating across the membrane into the cytoplasm of bacteria to act on intracellular targets.
In contrast to bacteria, the cytoplasmic membrane of mammalian cells is rich in the zwitterionic phospholipids phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin, providing a membrane with a neutral net charge.Therefore, interactions between AMPs and mammalian cell membrane occur mainly via hydrophobic interactions, which are relatively weak compared to the electrostatic interactions taking place between AMPs and bacterial membranes.
Due to greater affinity for the LPS, AMPs displace the divalent cations and bind to the LPS. By being bulky, the AMPs then cause transient cracks and permeabilize the outer membrane, thereby permitting passage of the peptide itself across the membrane.
Membrane permeabilization by AMPs is suggested to initially lead to leakage of ions and metabolites, depolarization of the transmembrane potential with subsequent membrane dysfunction (e.g., impaired osmotic regulation and inhibition of respiration), and ultimately, membrane rupture and rapid lysis of microbial cells.
Ex: 1) LL-37, which has recently been evaluated in a phase I/II clinical trial as a local treatment to enhance healing of venous leg ulcers.
2) PXL01, which similarly to hLF1-11 is derived from human lactoferricin, has been evaluated in a hyaluronic acid-based gel formulation in a phase II clinical trial for prevention of post-surgical adhesion formation in connection to hand surgery.
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->Characteristics of an ideal antibiotic:
ReplyDelete>An ideal antibiotic is broad spectrum.
>This means that it is effective against many different pathogenic microbes.
>It should have long shelf life and hence should be chemically stable.
>It should not have any toxic and undesirable side effect on host.
>It should not lead to development of resistant strains of microbes.
>An ideal antibiotic is an antibacterial agent that kills or inhibits the growth of all harmful bacteria in a host, regardless of site of infection without affecting beneficial gut microbes (gut flora) or causing undue toxicity to the host.
>Remains active in tissues and body fluids
>Complements or assists the activities of the host's defense
>Remains potent long enough to act and is not broken down or excreted prematurely
>Relatively soluble, function even when highly diluted in body fluids
Siderophores:
ReplyDeleteSiderophores are defined as low molecular weight ferric ion specific chelating molecules produced under iron-limiting condition by microbes and their most notable function is to sequester iron from host and provide this essential metal nutrient to microbes.
They usually form a stable octahedral complex with ferric ion. Siderophores are related to virulence mechanism and have additional clinical application and are possibly important in agriculture.
Major classes are:
Catecholates,
Hydroxamates,
Carboxylates.
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Characteristics of an ideal antibiotic:
ReplyDelete-It should be stable and have long shelf life.
-Wide spectrum: It must be active against a wide range of pathogen.
-The pathogen should not gain resistance easily against the antibiotic.
-Selective nature: It must act only against the target and not the host organism.
-When orally administered should not affect the normal gut flora.
-At low concentration also it should have broad spectrum of antimicrobial activity.
-It should not interfere with the host's natural defense mechanism such as phagocytosis.
-It should have more bactericidal activity rather than bacteristatic activity.
-Rate of biotransformation and elimination of antibiotic should be sufficiently slow to allow a convenient dosing schedule.
-It should not have allergic or hypersensitive reactions.
-It should have sufficient solubility in aqueous fluid to facilitate good distribution to all body tissues.
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Antifungal agents and their mode of action:
ReplyDelete1. membrane distrupting agents -Amphotericin B ,Nystatin
2.ergosterol synthesis inhibitors- azoles , morpholine
3.nucleic acid inhibitor- flucytosine
4.antimitotic (spindle distruption)- griseofulvin
5.glucan synthesis inhibitors-Echinocandins
6.chitin synthesis inhibitor-nikkomycin
7.protein synthesis inhibitor-sordarins, azasordarins
bacteriostatic antibiotics:
ReplyDeleteTetracyclins
Chloramphenicol
Erythromycin
Lincomysin
bacteriocidal antibiotics:
Cephalosporin
Penicillin
Erythromycin
Aminoglycosides
Cotrimoxazole
Ideal antibiotics should have the following characteristics:
ReplyDelete1. selective toxic to microbe but non toxic to host cell
2.relatively soluble, function even when highly diluted in body fluid
3.wide spectrum: must be active against wide range of pathogens.
4.not disturb the normal gut flora when orally administered
5.reasonably priced
6.bactericidal rather than bacteriostatic
antibiotics on the basis of mechanism of action:
ReplyDelete1.protein synthesis inhibitors:
inhibit 30s subunit -Gentamycin
-Tetracyclins
inhibit 50s subunit -Chloramphenicol
-Clindamycin
-Macrolides
2.DNA synthesis inhibitors- Fluoroquinolones
- Metronidazole
3.RNA synthesis inhibitors- Rifampin
4.mycolic acid inhibitors-Isoniazid
5.folic acid synthesis inhibitors-Sulfonamides
-Trimethoprim
Class of antibiotics
ReplyDelete1Penicillins such as penicillin and amoxicillin
2Cephalosporins such as cephalexin (Keflex)
3 Macrolides such as erythromycin (E-Mycin), clarithromycin (Biaxin), and azithromycin (Zithromax)
4Fluoroquinolones such as ciprofolxacin (Cipro), levofloxacin (Levaquin), and ofloxacin (Floxin)
5Sulfonamides such as co-trimoxazole (Bactrim) and trimethoprim (Proloprim)
6Tetracyclines such as tetracycline (Sumycin, Panmycin) and doxycycline (Vibramycin)
7Aminoglycosides such as gentamicin (Garamycin) and tobramycin (Tobrex)
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How does Antimicrobial Resistance happen?
ReplyDeleteAntibiotic resistance occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm.
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What is the best natural antibiotic?
ReplyDelete1.Garlic. Cultures across the world have long recognized garlic for its preventive and curative powers.
2.Honey. Since the time of Aristotle, honey has been used as an ointment that helps wounds to heal and prevents or draws out infection.
3.Ginger.
4.Echinacea.
5.Goldenseal.
6.Clove.
7.Oregano.
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What is the strongest antibiotic for bacterial infection?
ReplyDeleteAmoxicillin/potassium clavulanate (Augmentin) is a moderately priced drug used to treat certain kinds of bacterial infections. This drug is more popular than comparable drugs.
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What are the most common side effects of antibiotics?
ReplyDeleteThe most common side effects of antibiotics affect the digestive system. These occur in around 1 in 10 people.
.vomiting.
.nausea (feeling like you may vomit)
.diarrhoea.
.bloating and indigestion.
.abdominal pain.
.loss of appetite.
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What are the classes of antiviral drugs?
ReplyDelete.Nucleoside reverse transcriptase inhibitors (NRTIs)
.Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
.Protease inhibitors (PIs)
.Integrase inhibitors (INSTIs)
.Fusion inhibitors (FIs)
.Chemokine receptor antagonists (CCR5 antagonists)
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What is the mode of action of antiviral medications?
ReplyDeleteIn principle, a molecule can act as an anti-viral drug if it inhibits some stage of the virus replication cycle, without being too toxic to the body's cells. The possible modes of action of anti-viral agents would include being able to Prevent synthesis of specific viral protein(s).
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Difference Between Antibacterial and Antibiotic?
ReplyDeleteAntibiotics are the chemical or physical agent produced naturally or artificially capable of inhibiting and killing the growing microorganisms, but antibacterial substances only work against the bacteria and these antibacterial compounds rather killing those harmful bacteria just help in slowing down their activities. It will not be wrong to say that ‘all antibiotics are antibacterial, but all antibacterial is not antibiotics.’
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Diffreance between antiviral drug or antibiotics?
ReplyDeleteAntivirals: are drugs that can treat people who have already been infected by a virus. They also can be used to prevent or limit infection when given before or shortly after exposure, before illness occurs. A key difference is that the antiviral drug is effective only when administered within a certain time frame before or after exposure and is effective during the time that the drug is being administered.
Antibiotics:are medicines that interfere with the reproduction of bacteria and are, therefore, only useful for treating bacterial infections. Viral diseases, like influenza, can therefore not be treated with antibiotics. What is worse, inappropriate use of antibiotics contributes to the development of antibiotic resistance, a growing health concern. Secondary bacterial infections that may occur in tissues that have been damaged by influenza virus infection may well be treated with antibiotics.
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Q Ideal characteristics of antibiotics?
ReplyDeleteA 1) Easy Solubility in body fluids.
2) Selective toxicity to microorganisms and nontoxiciy to host.
3) It must be bacteriocidal and not bacteriostatic.
4) Must remain potent long enough to act upon.
5) Must be nonallergic to host.
6) Easy availability must be there and cost must be low.
7) Higher penetration through surfaces required.
8) Homogenicity in preparation of antibiotics must be there.
9) Must not lead to development of antibiotics resistance.
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Ideal characteristics of an antibiotic agent
ReplyDelete1. Should have selective toxicity against pathogens and not the host.
2. Should not disturb the normal Flora of the host's body/gut.
3. Should be able to kill the pathogens before the pathogen develops resistance against the antibiotic.
4. The antibiotic agent should be able to dissolve readily in water, body fluids and other solvents. For it to be effective, it shouldn't be dissipated too quickly or shouldn't remain in the body for too long as it will result in the development of resistance against the antibiotic by the pathogens.
5. The antibiotic agent should be stable and shouldn't lose it's biological activity (maximum bactericidal or bacteriostatic properties) . Should have the same therapeutic activity when maintained at a constant concentration in blood and tissue fluids over time.
6. Should not cause any side effects to the host upon administration.
7. Should have longer shelf life and should have reasonable cost.
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Q. what is proteom?
ReplyDeleteA. It is the entire complement of proteins that is or can be expressed by a cell, tissueb or organism.
Q. What is genome ?
A. It is the complete set of genes or genetic material present in a cell or organism.
Q. What is Trancriptome?
A. The transcriptome is the set of all RNA molecules in one cell or a population of cells.
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DeleteQ: Siderophores:Siderophores are low molecular weight Fe3+ chelating molecules produced under iron-limiting conditions.
ReplyDeleteRiboswitch: riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA.
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Question :- WHO priority pathogens list for R&D of new antibiotics.
ReplyDeleteAns:-
Priority 1: CRITICAL
▪Acinetobacter baumannii, carbapenem-resistant
▪Pseudomonas aeruginosa, carbapenem-resistant
▪Enterobacteriaceae, carbapenem-resistant, ESBL-producing
Priority 2: HIGH
▪Enterococcus faecium, vancomycin-resistant
▪ Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant
▪Helicobacter pylori, clarithromycin-resistant
▪Campylobacter spp., fluoroquinolone-resistant
▪Salmonellae, fluoroquinolone-resistant
▪Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant
Priority 3: MEDIUM
▪Streptococcus pneumoniae, penicillin-non-susceptible
▪Haemophilus influenzae, ampicillin-resistant
▪Shigella spp., fluoroquinolone-resistant
Ref:-https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.who.int/news-room/detail/27-02-2017-who-publishes-list-of-bacteria-for-which-new-antibiotics-are-urgently-needed&ved=2ahUKEwi11NnP7qzjAhXQ4XMBHQoNAIQQFjAAegQIARAB&usg=AOvVaw2KKAMa4wkTZ-GwtAck8ksU
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Question:- what is Proteome and transcriptome?
ReplyDeleteAns:-
proteome:-
The proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time. It is the set of expressed proteins in a given type of cell or organism, at a given time, under defined conditions. Proteomics is the study of the proteome.
Transcriptome:-
The transcriptome is the set of all RNA molecules in one cell or a population of cells. It is sometimes used to refer to all RNAs, or just mRNA.
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Q.Antibiotic Grouping By Mechanism:
ReplyDeleteCell Wall Synthesis inhibitor:Penicillins, Cephalosporins, Vancomycin, Beta-lactamase Inhibitors, Carbapenems, Aztreonam, Polymycin, Bacitracin.
Protein Synthesis Inhibitors: Inhibit 30s Subunit:Aminoglycosides (gentamicin),Tetracyclines.
Inhibit 50s Subunit, Macrolides, Chloramphenicol, Clindamycin, Linezolid, Streptogramins.
DNA Synthesis Inhibitors: Fluoroquinolones, Metronidazole.
RNA synthesis Inhibitors: Rifampin
Mycolic Acid synthesis inhibitors: Isoniazid
Folic Acid synthesis inhibitors: Sulfonamides, Trimethoprim
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Q: What is transcriptome?
ReplyDeleteans:the sum total of all the messenger RNA molecules expressed from the genes of an organism.
Q: What is proteome?
Ans: The proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time.
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Antifungals and their mode of action:
ReplyDelete1.Polyene antibiotics.
A. Amphotericin B:
Amphotericin B is prototype of polyene antibiotics and have high affinity for ergosterol present in fungal cell membrane.
It then gets combined with the membrane and get inserted into the membrane and several molecules together orient themselves in such a way as to form the micropore.
B. Nystatin:
It binds to fungal cell membrane (Ergosterol) and forms pores.
This alters permeability & transport and as a result, cell death occurs.
2.Heterocyclic benzofuran.
Griseofulvin:
It is fungistatic in nature.
It interferes with mitosis-multinucleated and stunned fungal hyphae result from its action.
It causes abnormal metaphase configuration, however doesn’t cause metaphase arrest, rather the daughter nuclei fail to move apart or move only a short distance.
It does not inhibit polymerization of tubulin but somehow disorients the microtubules.
3. Echinocandins.
Echinocandins interfere with the synthesis of the fungal cell wall.
It is Glucan synthesis inhibitor.
It inhibits 1,3- beta glucan synthase, an enzyme important in fungal cell wall synthesis and subsequently inhibit the synthesis of beta glucan in the fungal cell wall.
Disruption of the fungal cell wall leads to cellular osmotic instability and cell death.
4. Terbinafine.
It interferes with ergosterol biosynthesis by inhibiting the fungal enzyme squalene epoxidase rather than interacting with the P450 system. The accumulation of toxic amounts of squalene result in the death of the fungal cell.
5. Antimetabolite.
Flucytosine:
Flucytosine is taken up by fungal cells via the enzyme cytosine permease.
5-FC is then converted by a series of steps to 5-fluorodeoxyuridine 5’-monophosphate. 5-fluorodeoxyuridine 5’-triphosphate is incorporated into fungal RNA, where it disrupts nucleic acid and protein synthesis.
6. Azoles.
The azole antifungal drugs act by inhibiting the synthesis of the sterol components of the fungal membrane.
Azoles are predominantly fungistatic.
They inhibit C-14 α-demethylase (a cytochrome P450 [CYP450] enzyme), thereby blocking the demethylation of lanosterol to ergosterol, the principal sterol of fungal membranes.
This inhibition disrupts membrane structure and function, which then inhibits fungal cell growth.
7. Topical antifungals.
A. Ciclopirox:
Ciclopirox inhibits the transport of essential elements in the fungal cell, disrupting the synthesis of DNA, RNA, and protein.
B. Tolnaftate:
Tolnaftate distorts the hyphae and stunts mycelia growth in susceptible fungi.
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Proteome: The term "proteome" was coined from the PROTEin complement of the genOME in 1994 by Marc Wilkins. Proteome is the complete set of proteins expressed and modified following their expression by the genome. The large-scale study of proteomes is proteomics.
ReplyDeleteGenome: A genome is an organism’s complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism. The study of genome is termed genomics.
Transcriptome: A transcriptome is complete set of RNA transcripts produced by the genome at any one time. The study of the transcriptome is termed transcriptomics.
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Question:-Classification of antifungal.
ReplyDeleteAns:-
Classification based on mechanism of action:-
1. Fungal cell wall synthesis inhibition:- Caspofungin.
2. Bind to fungal cell membrane ergosterol:-Amphotercin-B, Nystatin.
3. Inhibition of ergosterol + lanosterol synthesis:-Terbinafine, Naftifine, Butenafine.
4. Inhibition of ergosterol synthesis:- Azoles .
5. Inhibition of nucleic acid synthesis:-Flucytosine.
6. Disruption of mitotic spindle and inhibition of fungal mitosis:- Griseofulvin .
7.Miscellaneous:- Ciclopirox, Tolnaftate, Haloprogin, Undecylenic acid, Topical azoles.
Classification based on structure:-
• ANTIBIOTICS:-
Polyene:-Amphotericin, nystatin, hamycin Hetrocyclic
Benzofuran:- griseofulvin
• ANTIMETABOLITE:- Flucytosine
• AZOLES:-
Imidazoles: -Ketoconazole, clotrimazole, oxiconazole, miconazole
Triazoles:- Fluconazole, itraconazole, voriconazole
• ALLYLAMINES: - Terbinafine, butenafine
• ECHINOCANDINS:-
Caspofungin, anidulafungin, micafungin
• OTHER TOPICAL AGENTS :-
Tolnaftate, Undecyclinic acid, benzoic acid.
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Question:- What are characteristics of an ideal antimicrobial agent?
ReplyDeleteAns:-
• Solubility in body fluids to be transported in the body and reach the infectious organisms
• Selective toxicity:-They must be more toxic to microorganisms than to host cells.
• Toxicity is not easily altered:-It should have a standard toxicity and not be made more or less toxic by interactions with foods or other drugs.
• Non allergenic:-It should not cause an allergic reaction.
• Stability:-It should maintenance of a constant, therapeutic concentration in blood and tissue fluids – should have the same therapeutic activity over many hours.
• Resistance by microorganisms not easily acquired.
• Long shelf-life
• Reasonable cost
• Narrowest sprectrum with fewest side effects.
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Mode of Action of Antiviral drugs:
ReplyDeleteThe possible modes of action of antiviral agents would include being able to...
(1) Inactivate extracellular virus particles
(2) Prevent viral attachment and/or entry
(3) Prevent Replication of the viral genome
(4) Prevent synthesis of specific viral protein(s)
(5) prevent assembly or release of new infectious visions
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What are Siderophores?
ReplyDeleteThey are small, high-affinity iron-chelating compounds secreted by microorganisms such as bacteria and fungi and serving to transport iron across cell membranes
Siderophores are amongst the strongest soluble fe+3 binding agents known
Examples of siderophores produced by various bacteria and fungi
(1) Desferrioxamine B= a hydroxamate siderophore
(2) Enterobactin= a catecholate siderophore.
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Antifungal class and their mode of action
ReplyDelete1) Polyene
They are composed of macrocyclic rings, where one side is lipophilic and other side is hydrophilic.
Eg. Amphotericin B produced by Streptomyces nodosus. It gets with ergosterol present in fungal cell membrane, and forms pore through which ions can enter. The cell permeability is thus increased which leads to cell death.
2.Heterocyclic benzofuran
Eg. Griseofulvin is produced by Penicillium griseofulvin. It interferes with mitosis, which causes abnormal metaphase configuration and hence daughter nuclei fail to move apart.
3. Echinocandins
It interferes with fungal cell wall synthesis by inhibiting 1,3- beta glucan synthase, which leads to disruption of the fungal cell wall, osmotic instability and ultimately cell death.
4. Terbinafine
It interferes with ergosterol biosynthesis by inhibiting the fungal enzyme squalene epoxidase. Squalene causes accumulation of unsaturated hydrocarbon, which is toxic and results in fungal cell death.
5. Azoles
They act by interfering with synthesis of sterilization components of fungal membrane. They inhibit C-14 α-demethylase and this would in turn block demethylation of lanosterol to ergosterol. It thus, disrupts membrane structure and inhibit fungal growth.
6.Topical antifungal
Eg. Ciclopirox, inhibits the transport of essential elements in the fungal cell, disrupting the synthesis of DNA, RNA, and protein.
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Riboswitches
ReplyDeleteRiboswitches was discovered in 2002 by Ronald Breaker, Henry Ford II professor and incoming department chair of Molecular, Cellular, and Developmental Biology,
Riboswitches are elements commonly found in the 5′-untranslated region (UTR) of mRNAs that exert their regulatory control over the transcript in a cis-fashion by directly binding a small molecule ligand. Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule.
Riboswitches are unique from other RNAs that serve as drug targets in that they have evolved to form structured and highly selective receptors for small drug-like metabolites. In most cases, metabolite binding to the receptor represses the expression of the gene or genes coded by the mRNA. If a new metabolite analog were designed that binds to the receptor, the gene(s) regulated by that riboswitch could be repressed, with a potentially lethal effect to the bacteria.
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Q. Why E.coli is called as good model organism?
ReplyDeleteAnswer.
The fact that E. coil is able to survive such variable conditions is one advantage that led to its use as a model organism. A model organism is a species that is extensively studied to understand a specific phenomenon, expecting that the knowledge gained can be applied to other species as well.
E. coli has many attributes that make it an ideal candidate for use as a model organism.
- E. coli is a single-celled organism. There are no ethical concerns about growing, manipulating, and killing bacterial cells, unlike multicellular model organisms like mice or chimps
- They are also tiny cells, so in a small laboratory you can have flasks containing billions of cells that take up very little room, allowing many experiments. Easy to mainatain.
- E. coli is able to reproduce and grow very rapidly, doubling its population about every 20 minutes. This is helpful in a lab situation where waiting for subsequent generations to produce experimental data can be the rate-limiting step. With E. coli it is as easy and fast as letting them grow overnight.
- E. coli can survive in variable growth conditions
- Culture media containing simple and inexpensive ingredients and nutrients can successfully spur E. coli to grow and divide.
- Most naturally occurring strains of E.coli are harmless.
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Proteome:-
ReplyDeleteA proteome is the complete set of proteins expressed by an organism. The term can also be used to describe the assortment of proteins produced at a specific time in a particular cell or tissue type. The proteome is an expression of an organism's genome
The study of the proteome is called proteomics, and it involves understanding how proteins function and interact with one another
Genome:-
A genome is an organism’s complete set of DNA, including all of its genes. Each genome contains all of the information needed to build and maintain that organism.
Transcriptome:-
A transcriptome is the full range of messenger RNA, or mRNA, molecules expressed by an organism. The term "transcriptome" can also be used to describe the array of mRNA transcripts produced in a particular cell or tissue type.
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Proteome:-
ReplyDeleteA proteome is the complete set of proteins expressed by an organism the term can also be used to describe the assortment of proteins produced at a specific time in a particular cell or tissue type. The proteome is an expression of an organisms genome the proteome actively changes in response to various factors, including the organisms developmental stage and both internal and external conditions.
The proteome can be studied using a variety of techniques. For eg two dimensional gel electelectrophoresis can be used to seperate proteins by their sizes and by their charges.
The proteome can also be studied using another laboratory technique called mass spectrometry, which identifies specific proteins within complex samples.
Transcriptome:-
A transcriptome is the full range of messengerRNA, molecules expressed by an organism. The term transcriptome can also be used to describe the array of mRNA transcripts produced in a particular cell or tissue type. In contrast with the genome, which is characterized by its stability, the transcriptome actively changes.
A laboratory technique called the micro array can be used to examine changes in the transcriptome
Microarrays can be used to measure the expression of thousands of genes at the same, time as well as to provide gene expression profiles, which describe changes in the transcriptome in response to a particular condition or treatment.
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->antibiotics on the basis of mechanism of action:
ReplyDelete>Penicillins
Mechanism
o interferes with bacterial cell wall synthesis
>Cephalosporins
Mechanism
• disrupts the synthesis of the peptidoglycan layer of bacterial cell walls
>Fluoroquinolones
Mechanism
oblocks DNA replication via inhibition of DNA gyrase
>Aminoglycosides
Mechanism
o inhibition of bacterial protein synthesis
>Vancomycin
Mechanism
o an inhibitor of cell wall synthesis
>Rifampin
• Most effective against intracellular phagocytized Staphylococcus aureus in macrophages
>Linezolid
•Linezolid binds to the 23S portion of the 50S subunit and acts by preventing the formation of the initiation complex between the the 30S and 50S subunits of the ribosome
->proteome:
ReplyDeleteThe proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time. It is the set of expressed proteins in a given type of cell or organism, at a given time, under defined conditions
>>Transcriptome:
ReplyDeleteThe transcriptome is the set of all RNA molecules in one cell or a population of cells. It is sometimes used to refer to all RNAs, or just mRNA, depending on the particular experiment. It differs from the exome in that it includes only those RNA molecules found in a specified cell population, and usually includes the amount or concentration of each RNA molecule in addition to the molecular identities.
The transcriptome can be seen as a subset of the proteome, that is, the entire set of proteins expressed by a genome.
Transctiptome-
ReplyDeleteTranscriptome is the set of RNA present in the cell which can be transcribe. It was fond that in humans less then 5% RNA is transcriptome
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Why E.coli is model organism?
ReplyDeleteE.coli is used because almost all the genes present in E.coli genome and their functions are known. it have consists of approximately 4.6 million base pairs and encodes about 4000 different proteins.
The rapid growth if E.coli in laboratory condictions is also an advantage.E. coli divide every 20 to 60 minutes.
The nutrient mixtures in which E. coli divide most rapidly include glucose, salts, and various organic compounds, such as amino acids, vitamins, and nucleic acid precursors. However, E. coli can also grow in much simpler media consisting only of salts, a source of nitrogen (such as ammonia), and a source of carbon and energy (such as glucose). In such a medium, the bacteria grow a little more slowly (with a division time of about 40 minutes) because they must synthesize all their own amino acids, nucleotides, and other organic compounds. The ability of E. coli to carry out these biosynthetic reactions in simple defined media has made them extremely useful in elucidating the biochemical pathways involved. Thus, the rapid growth and simple nutritional requirements of E. coli have greatly facilitated its use.
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How is normal flora acquired?
ReplyDeleteAcquisition of the normal body flora. Prior to birth, most humans are essentially sterile microbiologically. ... The diet of the new borne plays a decisive role in the microbial population of the gut with the flora of breast-fed infants being dominated by organisms such as Bifidobacteriumbifidus.
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Why dose microbiome affect human helath?
ReplyDeleteThe gut microbiome plays a very important role in your health by helping control digestion and benefiting your immune system and many other aspects of health. An imbalance of unhealthy and healthy microbes in the intestines may contribute to weight gain, high blood sugar, high cholesterol and other disorders.
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How does the gut microbiome influence serotonin levels?
ReplyDeleteTo start, we explored the idea that normal gut microbes could influence levels of neurotransmitters in their hosts." Peripheral serotonin is produced in the digestive tract by enterochromaffin (EC) cells and also by particular types of immune cells and neurons. ... "EC cells are rich sources of serotonin in the gut.
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How do you know if you have a leaky gut?
ReplyDeleteWhen the gut is "leaky" and bacteria and toxins enter the bloodstream, it can cause widespread inflammation and possibly trigger a reaction from the immune system. Supposed symptoms of leaky gut syndrome include bloating, food sensitivities, fatigue, digestive issues and skin problems
This comment has been removed by the author.
ReplyDeleteHuman Microbiome Project
ReplyDeleteImportant components of the HMP were culture-independent methods of microbial community characterization, such as metagenomics (which provides a broad genetic perspective on a single microbial community), as well as extensive whole genome sequencing (which provides a "deep" genetic perspective on certain aspects of a given microbial community, i.e. of individual bacterial species). The latter served as reference genomic sequences — 3000 such sequences of individual bacterial isolates are currently planned — for comparison purposes during subsequent metagenomic analysis. The project also financed deep sequencing of bacterial 16S rRNA sequences amplified by polymerase chain reaction from human subjects.
On 13 June 2012, a major milestone of the HMP was announced by the NIH director Francis Collins. The announcement was accompanied with a series of coordinated articles published in Nature and several journals including the Public Library of Science (PLoS) on the same day.By mapping the normal microbial make-up of healthy humans using genome sequencing techniques, the researchers of the HMP have created a reference database and the boundaries of normal microbial variation in humans.
From 242 healthy U.S. volunteers, more than 5,000 samples were collected from tissues from 15 (men) to 18 (women) body sites such as mouth, nose, skin, lower intestine (stool) and vagina. All the DNA, human and microbial, were analyzed with DNA sequencing machines. The microbial genome data were extracted by identifying the bacterial specific ribosomal RNA, 16S rRNA. The researchers calculated that more than 10,000 microbial species occupy the human ecosystem and they have identified 81 – 99% of the genera. In addition to establishing the human microbiome reference database, the HMP project also discovered several "surprises", which include:
Microbes contribute more genes responsible for human survival than humans' own genes. It is estimated that bacterial protein-coding genes are 360 times more abundant than human genes.
Microbial metabolic activities; for example, digestion of fats; are not always provided by the same bacterial species. The presence of the activities seems to matter more.
Components of the human microbiome change over time, affected by a patient disease state and medication. However, the microbiome eventually returns to a state of equilibrium, even though the composition of bacterial types has changed
Q. Types of antifungal agent and their mode of action.
ReplyDeleteAns: Antifungal agent is a drug that selectively eliminates fungal pathogens from a host with minimal toxicity to the host.
TYPES:-
1. Polyene- Amphoterin, nystatin, and pimaricin interact with sterols in the cell membrane to form channels through which small molecules leak from the inside of the fungal cell to the outside.
2. Azole- Fluconazole, itraconazole and ketoconazole inhibit cytochrome P450-dependent enzymes involved in the biosynthesis of ergosterol, which is required for fungal cell membrane structure and function.
3. Allylamines and Morpholine- Allylamines inhibit ergosterol biosynthesis at the level of squalene epoxidase. The morpholine drug, amorolfine, inhibits the same pathway later.
4. 5-Fluorocytosine- 5-Fluorocytosine acts as an inhibitor of both DNA and RNA synthesis via the intracytoplasmic conversion of 5-fluorocytosine to 5-fluorouracil.
5. Griseofulvin- Griseofulvin is an antifungal antibiotic produced by Penicillium griseofulvum. It is used for chronic infections caused by these fungi and it inhibits mitosis in fungi.
Q. Difference between Planktonic form and sessile(biofilm) form.
ReplyDeleteAns. In Planktonic form:
i) They move freely.
ii) They grow faster.
iii) Low Population density.
iv) Low Quorum sensing.
v) Less susceptible towards antibiotic.
vi) High rate of metabolism in planktonic form.
- Sessile(biofilm) form:
i) They are not free, attach to surface.
ii) They grow slow.
iii) High Population density.
iv) High Quorum sensing.
v) More susceptible towards antibiotic.
vi) Rate of metabolism is low in sessile form.
->Why E.coli is model organism?
ReplyDeleteBecause of their comparative simplicity, prokaryotic cells (bacteria) are ideal models for studying many fundamental aspects of biochemistry and molecular biology.
The most thoroughly studied species of bacteria is E. coli, which has long been the favored organism for investigation of the basic mechanisms of molecular genetics.
Most of our present concepts of molecular biology—including our understanding of DNA replication, the genetic code, gene expression, and protein synthesis—derive from studies of this bacterium.
The genome of E. coli, for example, consists of approximately 4.6 million base pairs and encodes about 4000 different proteins. The human genome is nearly a thousand times more complex (approximately 3 billion base pairs) and encodes about 100,000 different proteins .
The small size of the E. coli genome provides obvious advantages for genetic analysis, and the sequence of the entire E. coli genome has been determined.
Molecular genetic experiments are further facilitated by the rapid growth of E. coli under well-defined laboratory conditions. Depending on the culture conditions, E. coli divide every 20 to 60 minutes. Moreover, a clonal population of E. coli, in which all cells are derived by division of a single cell of origin, can be readily isolated as a colony grown on agar-containing medium .
Q:- who list of priority pathogens
ReplyDeleteA:- as antibiotic-resistant bacteria continue to spread, calls for new therapeutis are getting louder. In response, the world Health Organization wHO has drawn up a list of the twelve most important bacteria for which new drugs urgently must be developed.
Who experts, along with researchers from the University of Tubingen have published a global priority pathogens list of bacteria that pose a particular risk to human health and for which new drugs urgently need to be developed bacteria that are resistant to several antibiotics represent the greatest threat. The list is divided into three groups with different priorities
Priority 1) Acinetobacter baumannii, carbapenem resistant Pseudomonas aeruginosa, Enterobacteriaceae, carbapenem resistant, ESBL producing.
2) HIGH:- Enterococcus fascism, vancomycin resistant Staphylococcus sure us, Methicillin resistant Helicobacter pylori, Neisseria gonorrhea, cephalosporin resistant
Medium 3) Streptococcus pneumonia, penicillin-non-susceptible
Haemophilus influenza, ampicillin- resistant Shigella app, fluoroquinolone- resistant.
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Skin PH Measurement Methods
ReplyDelete(1) Colorimetric Method
The earliest studies done by using indicators that change color with PH.
This method is complicated, involving collection of indicator solution from the skin.
It was simplified by usage of indicator impregnated strips (Foil-Colorimetry)
(2) Potentiometric Method
Easy to use and most frequently utilized nowadays.
The most common method is using the hydrogen ion-selective glass electrode with internal reference electrode, called glass electrode.
The electrode is often planar shaped to make it more easily applied on the skin.
Other methods suggested recently, but not yet commonly employed.
-ion selective field effect transistor as a sensor, require small measurement area compared to the glass electrode.
-electron spin resonance imaging and confocal microscopy.
-they require treatment of the skin with an indicator substance, which penetrates into the epidermis and allows the PH to be detected in several layers simultaneously.
Why the human body temperature is 37 degrees Celsius ??
ReplyDeleteApparently it's the perfect balance as it's warm enough to prevent fungal infection and also it is an optimum temperature for the enzymes in our body.If it's too cold, the enzymes will too become ineffective (their function will slow down too much) When it's too hot sweat glands will produce sweat.
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Q) Why is the human body temperature maintained at 37 degree Celsius only?
ReplyDeleteAns : We humans are Endotherms(produces heat internally) so a toasty body temperature helps keep nasty fungal infections at bay.
#The number of fungal species that can thrive and, therefore, infect an animal/humans declines by 6 percent for every 1.8 degree F (1 C) rise in temperature.
#For maintaining 37.77 C as the normal body temperature takes a lot of food to keep the fire burning that hot.
#It also helps to balance the blood vessels from expansion and contraction.
#Rise in body temperature may lead our proteins and cells from functioning properly and lead to death.
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Question: why is the body temperature set at 37 celsious?
ReplyDeleteAnswer: 37 Celsius seems to be the average temperature that keeps all the body processes at an optimum.The human body depends mainly on metabolism in the body in order to live, metabolism means breaking down compounds and building them up again to support different cells. All these chemical reactions which depends on enzymes and different proteins which needs the 37C as an atmosphere to work in, note that when body's temperature exceeds 37.4C it enters the fever state and if it continues to raise up, denaturation of the proteins will take place and the human body wont be able to continue metabolic processes.
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Question:-How is body temperature regulated at 37 °c ?
ReplyDeleteAns:-Our internal body temperature is regulated by a part of our brain called the hypothalamus. The hypothalamus checks our current temperature and compares it with the normal temperature of about 37°C. If our temperature is too low, the hypothalamus makes sure that the body generates and maintains heat. If, on the other hand, our current body temperature is too high, heat is given off or sweat is produced to cool the skin.
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Question:-What will happen if body temperature changes from 37 °C?
ReplyDeleteAns:-
》 A decrease in metabolism, an abnormality in mechanical muscular function, or exposure to ambient temperatures below the normal body temperature may result in hypothermia. At a temperature of 32°C (89.6°F), oxygen consumption decreases as a function of hypometabolism, the oxygen dissociation curve shifts to the left so that less oxygen is given up to the tissues, and there is a generalized inhibition of enzyme activity.
》Excessive exposure to high ambient temperatures, an increase in heat production (either by increased metabolism or, more often, by increased muscular work) or loss of the ability to dissipate sufficient body heat may result in hyperthermia.
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Q. Why is the optimal temperature of human body is 37°c ?
ReplyDeleteAns. As this body temperature helps to avoid fungal infection.It is perfect balance,as it is warm enough to prevent fungal infection but not so hot that we need to eat nonstop stop to maintain our metabolism.the fungal species that can thrive and infect an animal declines by 6% for every 1°C rise in temperature.this suggest that by maintaining body temperature we are less susceptible to fungal infection.
- in nutshell it is because of protein and because we eat.human body mechanism generate heat. If too much heat is produced, the protein will denature and if too less heat is produced,the protein function will fail.
Q) How to measure the skin pH ?
ReplyDeleteAns : 1) Flat glass pH electrode.
2) Ion Sensitive Field Effect
Transistor pH electrode.
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Q. Methods for measurement of skin pH
ReplyDeleteAns. A) colorimetric methods:
This method involves the application of an indicator to the skin, recollection in a tube and the color change is measured with colorimeter.
B) planar glass electrode method:
It is the one unit containing both the active and reference electrodes also known as combined electrode. It is the most widely method used today to measure skin surface pH
Other methods for skin surface pH include the use of pH sensitive fluorescent dyes, electron spin resonance imaging.
Q. Why E.coli is used as model organism?
ReplyDeleteAns. Due to its high efficiency of introduction of DNA molecules into cells.
- because of its rapid growth rate and the ability to express proteins at very high levels.
- we had detailed knowledge of its nucliec acid and biosynthetic pathways.
- E.coli has less genome complexity.
- E.coli is single celled organism that can be manipulated easily and killed with no ethical concerns.
Q: why E.coli serves as a model organism?
ReplyDeleteAns. E. coli has many attributes that make it an ideal candidate for use as a model organism. Let's discuss the five major attributes that make E. coli an excellent model organism.
Attribute 1: E. coli is a single-celled organism. There are no ethical concerns about growing, manipulating, and killing bacterial cells, unlike multicellular model organisms like mice or chimps. They are also tiny cells, so in a small laboratory you can have flasks containing billions of cells that take up very little room, allowing many experiments.
Attribute 2: E. coli is able to reproduce and grow very rapidly, doubling its population about every 20 minutes. This is helpful in a lab situation where waiting for subsequent generations to produce experimental data can be the rate-limiting step. With E. coli it is as easy and fast as letting them grow overnight. Trying to study the same process in subsequent generations of elephants, for example, would require several generations of scientists and more elephants than we have on the planet!
Attribute 3: E. coli can survive in variable growth conditions. As we discussed earlier, this leads to it being very adaptive yet forgiving in lab situations. Culture media containing simple and inexpensive ingredients and nutrients can successfully spur E. coli to grow and divide.
Q:Why E.coli serves as a model organism?
ReplyDeleteAns.E. coli has many attributes that make it an ideal candidate for use as a model organism. Let's discuss the five major attributes that make E. coli an excellent model organism.
Attribute 1: E. coli is a single-celled organism. There are no ethical concerns about growing, manipulating, and killing bacterial cells, unlike multicellular model organisms like mice or chimps. They are also tiny cells, so in a small laboratory you can have flasks containing billions of cells that take up very little room, allowing many experiments.
Attribute 2: E. coli is able to reproduce and grow very rapidly, doubling its population about every 20 minutes. This is helpful in a lab situation where waiting for subsequent generations to produce experimental data can be the rate-limiting step. With E. coli it is as easy and fast as letting them grow overnight. Trying to study the same process in subsequent generations of elephants, for example, would require several generations of scientists and more elephants than we have on the planet!
Attribute 3: E. coli can survive in variable growth conditions. As we discussed earlier, this leads to it being very adaptive yet forgiving in lab situations. Culture media containing simple and inexpensive ingredients and nutrients can successfully spur E. coli to grow and divide.
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Q:Difference between a genome and a transcriptome?
ReplyDeleteAns. The genome is the DNA sequence.The transcriptome is what gets actually converted into mRNA.
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Q latest discovery on antibiotic
ReplyDeleteTeixobactin was discovered using a new method of culturing bacteria in soil, which allowed researchers to grow a previously unculturable bacterium now named Eleftheria terrae, which produces the antibiotic.
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new research on prevention of urinary catheter-associated infections by coating antimicrobial peptides:
ReplyDeleteUrinary catheters are extensively used in hospitals, being responsible for hospital-acquired infections. they designed antimicrobial peptide Chain in the context of urinary catheter-associated infections. Chain showed excellent antimicrobial activity against strains and clinical isolates of bacteria and yeast and demonstrated high stability in a wide range of temperatures, pH and salt concentrations. Moreover, the bactericidal activity of antimicrobial peptide chain on a model surface was studied against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), some of the most prevalent strains found in urinary catheter-associated infections. Chain surfaces can bind and kill by contact a high percentage of adherent bacteria. These achievements are obtained without any peptide modification Moreover, increased amounts of immobilized antimicrobial peptide chain lead to higher numbers of adhered/dead bacteria, revealing a concentration-dependent behaviour and demonstrating that Chain has excellent potential for developing antimicrobial urinary catheters.
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Ques. How to maintain a healthy gut microbiota?
ReplyDeleteAns. 1. Eat a wide range of plant-based foods. A healthy gut has a
diverse community of microbes, each of which prefers
different foods.
2. Avoid highly processed foods.
3. Eat more and more fiber as it is beneficial for gut
microbes.
4. Taking antibiotics only when needed and completing the
prescribed course of antibiotics.
5. Exercising and maintaining good body weight.
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Q:-Methods for measurement of skin pH
ReplyDeleteA:-Human skin is covered with an acidic mantle making it slightly acidic pH 4.8 to 6.0
The apparent pH value of skin can be measured by applying 1or 2 drops of DI water and placing a 6261-10C flat glass pH electrode or 004010D ISFET pH electrode on the moistened surface
There are two major techniques for measuring skin surface pH 1) The colorimetric technique and 2) The glass electrode potentiometric technique Early in this century, most studies were carried out using this colorimetric technique procedure with dye indicators. This procedure is less accurate because of the interference of many factors On the contrary, the glass electrode technique is more precise and sensitive than the colorimetric technique ,but the electrode technique still encounters interference from the biological potentials of the skin. This effect becomes minimal, however when a restricted area is selected for measurement
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Q.) Methods to measure pH of skin surface.
ReplyDeleteThe measurements of pH of skin can be divided into 2 parts, i.e outside skin pH ( related to skin surface) and inside skin pH ( related to the epidermis)
First significant measurement of skin pH was reported in 20th century by schade and merchionini using gas chain bell electrode.
1.colorimetric method
In 1930, Foil colorimetry was used, where indicator impregnated sheets of adsorbing strips are placed on the skin with water. The color change is then measured.
2. Potentiometric method
A.) Flat glass pH electrode- it has a planar shaped electrode known as a reference electrode.This measurement is non-invasive and produces only small electric current causing no skin damage. Both the sensing membrane and reference junction of a flat pH electrode are constructed on the flat surface tip of the electrode body.
B.) Another method uses ion selective field effect transistor as a sensor, which requires smaller measure-
ment area compared to the flat glass pH electrode.
C.) electron spin resonance
imaging and confocal microscopy require treatment of the skin with an indicator substance, which penetrates into the epidermis and allows the pH to be detected in several layers
simultaneously.
Q.) Methods to measure pH of skin surface.
ReplyDeleteThe measurements of pH of skin can be divided into 2 parts, i.e outside skin pH ( related to skin surface) and inside skin pH ( related to the epidermis)
First significant measurement of skin pH was reported in 20th century by schade and merchionini using gas chain bell electrode.
1.colorimetric method
In 1930, Foil colorimetry was used, where indicator impregnated sheets of adsorbing strips are placed on the skin with water. The color change is then measured.
2. Potentiometric method
A.) Flat glass pH electrode- it has a planar shaped electrode known as a reference electrode.This measurement is non-invasive and produces only small electric current causing no skin damage. Both the sensing membrane and reference junction of a flat pH electrode are constructed on the flat surface tip of the electrode body.
B.) Another method uses ion selective field effect transistor as a sensor, which requires smaller measure-
ment area compared to the flat glass pH electrode.
C.) electron spin resonance
imaging and confocal microscopy require treatment of the skin with an indicator substance, which penetrates into the epidermis and allows the pH to be detected in several layers
simultaneously.
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Q.) Why e.coli is used as a model organism?
ReplyDelete1. Fast growth in chemically modified media, where media is relatively cheaper.
2.It does not form aggregates and is industrially scalable.
3.There's extensive knowledge about its genome, transcriptome,proteome and metabolome.
4. There are no ethical concerns regarding its killing, manipulation or growth.
5.They have short generation time of 20 mins, it would help in obtaining experimental data in less time.
6.Its genome is small i.e. 4.5- 5.5 Mbp.
7.Mutants are easily obtained using well established methods and screening techniques, which has enabled many biochemical processes to be linked back to the molecular genetic level.
8. It can be isolated from recreational water and human faeces, hence easily available.
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Q:- why E.coli is used as a model organism?
ReplyDeleteA:-A model organism can help scientists perform faster and more efficient biological research. This lesson examines the most utilized model organism, e.coli and looks at the major characteristics that make it a perfect model.
The fact that E.coli is able to survive such variable conditions is one advantage that led to its use as a model organism.
E.coli has many attributes that make it an ideal candidate for use a a model organism
The reason of widespread use of ecoli for study purpose is the ease of its maintenance and breeding in laboratory environment plus it's meticulous experimental advantages. As compared to other living organism more is known about ecoli because of its simple nutritional requirements, rapid growth rate, and most important its well established genetics. Rate of cell division of ecoli is average of once in every 30 min, this enabling quick environmental adaptation. This fast division rate of E.coli has helped in evolutionary experiments which are conducted in the laboratories.
Recent research in E.coli uses modern techniques such as Super resolution and Andors SURE stream, which can provide a boost in resolution to 50-150 nm making it especially useful for the study of E. Coli. Cells.
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Q:- why is the human body temperature is maintained at 37 degree Celsius ?
ReplyDeleteA:- The human body is always producing heat energy from the food that we eat .basically heat is a byproduct of the various functions that are performed buy the tissues of the body. Therefore, it is crucial for the body to continuously emit this heat so that the temperature of the body is maintained at 37 degree Celsius.
A healthy body functions best at an internal temperature if about 37°c but everyone has their own individual normal body temperature which may slightly higher or lower. Our bodies also constantly adapt their temperature to environmental conditions. It goes up when we exercise for instance, and lower at night .And higher in afternoon than in the morning.
Our internal body temperature is regulated by a part of our brain called hhypothalamus . Hypothalamus checks our current temperature and compares it with the normal temperature of about 37°C.
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This comment has been removed by the author.
ReplyDeleteQ. Bacterial species present in curd.
ReplyDeleteAns . There are total 250 species of Lactobacillus have been isolated from curd. The different species of genus Lactobacillus present in curd are Lactobacillus fermentum , Lactobacillus acidophilus, Lactobacillus confusus, Lactobacillus delbruckii, Lactobacillus lindneri, Lactobacillus helveticus,Lactobacillus bulgaris.
- other than these streptococcus thermophilus, Bifidobacterium longum , Bifidobacterium bifidum.
Q. Characteristics of probiotic bacteria.
ReplyDeleteAns. Probiotic bacteria should have following characteristics:
1) ability to resist and pass through gastric acid and pepsin in stomach .
2) ability to grow in intestine in presence of pancreatin and bile salts.
3) antibiotic resistance.
4) antimicrobial activity against pathogens.
5) adhesion to the epithelial lining of intestine.
Question : Why the human body temperature is 37˚C ?
ReplyDeleteAnswer :
human body temperature is 37 degrees Celsius (98.6 degrees Fahrenheit).
It is the perfect balance, it is warm enough to prevent fungal infection but not so hot that we need to eat nonstop to maintain our metabolism.
Fungal species that can thrive and infect an animal typically declines by 6 percent for every 1° C rise in temperature. So, we know we need a higher body temperature to ward off fungal infection
Scientists made mathematical model that analyzed the benefits gained by body temperatures that protect against fungi versus the costs (extra food consumption) required to maintain body temperatures between 30° and 40° C. The optimal temperature for maximizing benefits while minimizing costs was found to be 36.7° C, which closely approximates normal body temperature.
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Question : Why do we need to maintain body temperature 37?
ReplyDeleteAnswer :
It is the optimum temperature for the enzymes in our body.
Enzymes are proteins.
Enzymes have an optimum temperature too. At this temperature, they are at their most productive. For the enzymes in our bodies, optimum temperature is around 37˚ C.
If the body is too hot, it will lose water more easily (it will evaporate) leading to a higher risk of dehydration. It also take a lot of energy to heat the body. Maintaining a high temperature would mean the body had to have a higher metabolic rate.
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Question: How to measure pH of skin surface...
ReplyDeleteAnswer:
Non-invasive Dry pH Sensor
Flat pH electrodes, also called flat bottom pH electrodes
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Question : Bacterial Species present in curd..
ReplyDeleteAnswer:
Lactobacillus acidophilus
Lactococcus lactis
Lactococcus lactis cremoris
Bifidobacterium bifidum
Bifidobacterium longum
Lactobacillus bulgaricus
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Question: Characteristics of Probiotic...
ReplyDeleteAnserr:
Probiotics are defined as living bacteria
Characters:
It should able to pass through our digestive path , and able to
attach to the intestinal epithelia and colonise.
It should able to replicate.
It should prevent to make biofilm of pathogens.
It should able to maintain good viability.
It should be Anti-inflammatory, antimutagenic,
immunostimulatory.
It should non pathogenic and non toxic.
It should Capable of exerting a benificial effect on the host.
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Ques. Bacterias involved in probiotics?
ReplyDeleteAns. Bifidobacteria animalis in yogurt
Bifidobacteria breve in yakult
Bifidobacteria lactis in raw milk
Lactobacillus acidophilus in yogurt and fermented soy
products
Lactobacillus casei shirota in yakult
Lactobacillus lactis cremoris and Lactobacillus bulgaricus in
curd
Other common probiotic starins Saccharomyces, Enterococcus,
Streptococcus, Pediococcus, Leuconostoc, Bacillus,
Escherichia coli.
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Q.) Bacterial species present in curd.
ReplyDeleteA.)
Lactobacillus delbrueckii
Lactobacillus bulgaris
Streptococcus thermophilus
Streptococcus salivarius
Bifidobacterium adolescentis
Bifidobacterium bifidum
Lactobacillus casei
Lactobacillus acidophilus
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Q.) Characteristics of Probiotics.
ReplyDeleteA.) Probiotics should be:
1.regarded as safe from the basis of long-term human use.
2.able to adhere to host tissues especially to the intestinal mucus and epithelial cells to promote efficient host-microbial interactions.
3.able to utilize nutrients and substrates in a normal diet.
4.resistant to acid present in stomach and stable towards bile present in intestine. Hence, it should be persistent in digestive tract.
5.Non pathogenic and non toxic.
6.antagonistic against enteric pathogens
7.able to maintain good viability.
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Bacterial species present in curd.
ReplyDelete(1) Lactobacillus fermentum
(2) Lactobacillus acidophilus
(3) Lactobacillus confusus
(4) Lactobacillus delbruckii
(5) Lactobacillus lindneri
(6) Lactobacillus helveticus
(7) Lactobacillus casei
(8) Lactococcus lactis
(9) Lactococcus cremoris
(10) Leuconostoc lactis
(11) Bifidobacterium longum
(12) Bifidobacterium bifidum
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Any probiotic food has following benefits
ReplyDelete-Improve digestion
-boosts immune system
-fights food-borne illnesses
-improves bowel movement
-heals inflammation in the intestines
-prevents urinary tract infection
Bacterial species found in curd
ReplyDeleteLactobacillus bulgaris
Streptococcus thermophilus
Streptococcus salivarius
Bifidobacterium adolescentis
Lactobacillus casei
Lactobacillus acidophilus
Bifidobacterium bifidum
Lactobacillus delbrueckii
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Q:- Characteristics of Probiotics
ReplyDeleteA:-The initial screening and selection of probiotics includes testing of the following important criteria:- phenotype and genotype stability
Including plasmid stability
Carbohydrates and protein utilization patterns
Acid and bile tolerance and survival growth
Intestinal epithelial adhesion properties.
It is of high importance that the probiotics strain can survive the location where it is presumed to be active.
The probiotic strain can act as an adjuvant and stimulate the immune system against pathogenic microorganisms.
Safety in food and clinical use
Susceptible to antibiotics
Antagonism against enteric pathogens
Clinically validated and documented health effect
Persistence in the human intestinal tract
Adherence to human intestinal cells
Production of antimicrobial substances
Human origin
Acid and bile stability.
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Q:-Bacteria species present in curd
ReplyDeleteA:-Lactobacillus bulgaricus and Streptococcus thermophilus. These strains of Lactobacillus and streptococcus are examples of good bacteria. Other bacteria:-
Bifidobacterium bifidum
Bifidobacterium lactose
Bifidobacterium longer
Enterococcus fascism
Lactobacillus acidophilus
Lactobacillus casein
Lactobacillus Johnsonii
Lactobacillus gasseri
Lactobacillus plant arum
Saccharomyces boulardii.
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Q Why the human body temperature is 37°C?
ReplyDeleteA Sufficiently high temperature will destroy some tissues and critical substance in body and at sufficiently low temperature many chemical reactions needed in our bodies slow down too much,which can be dangerous. 37°C is perfect as it is warm enough to prevent fungal infections and not so hot as to require faster metabolism. Ambient condition are required to be maintained at equilibrium i.e the rate of heat dissipated is equal to the amount of heat generated,and is optained below 37°C.
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Q) Bacterial species present in curd
ReplyDeleteA) Lactobacillus acidophilus
Lactobacillus bulgaricus
Lactobacillus lactis
Lactobacillus casei
Lactobacillus Johnsonii
Sterptococcus thermophilus
Bifidobacterium bifidum
Bifidobacterium lactis
Lactobacillus plantarum
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>> Why the human body temperature is 37˚C ?
ReplyDeleteThe human body runs on a large number of biochemical processes. Breaking down of compounds and building them up again to support different cells, all these chemical reactions which depends on enzymes and different proteins which needs the 37 C as an atmosphere to work . However, it is dangerous to have too high a temperature because at some point, there are going to be unwanted chemical reactions, disrupting the useful ones. So there is a balance, which for human beings is about 37 C.
The enzymes and chemical reactions in the human body is optimal at 37 degrees Celsius. If it is too high, enzymes will denature and fail to perform its necessary function. If it is too low, the reaction rate is too slow
->>Methods for measurement of skin pH
ReplyDeleteSkin surface pH is a key parameter of the stratum corneum (SC) and an important regulator of the epidermal barrier homeostasis. The upper outermost skin layer exhibits pH values lower than the physiologic pH, characteristic for the body’s internal environment.
Different methods for the investigation of skin surface pH exist among which the flat glass electrode being the most widely used. In addition, pH-sensitive dyes, fluorescence lifetime imaging (FLIM) and more recently in vivo Raman confocal microscopy are employed in skin surface acidity investigation.
Human skin is covered with an acid mantle making it slightly acidic – pH 4.8 to 6.0. The apparent pH value of skin can be measured by applying 1 or 2 drops of DI water or physiological saline and placing a 6261-10C flat glass pH electrode or 0040-10D ISFET pH electrode on the moistened surface. The results may vary for test sites within an individual and between individuals.
>>Beneficial Properties of Probiotics:
ReplyDeleteProbiotics are live microorganisms intended to provide health benefits when consumed, generally by improving or restoring the gut flora.
It exhibit various health beneficial properties such as prevention of bowel diseases, improving the immune system, for lactose intolerance and intestinal microbial balance, exhibiting antihypercholesterolemic and antihypertensive effects, alleviation of postmenopausal disorders, and reducing traveller’s diarrhoea. Recent studies have also been focused on their uses in treating skin and oral diseases. In addition to that, modulation of the gut-brain by probiotics has been suggested as a novel therapeutic solution for anxiety and depression.
Probiotic strains exhibit powerful activity in human health improvement. The main probiotic groups are Lactobacillus, Bifidobacterium, Pediococcus, Lactococcus, Bacillus and yeasts strains which are used frequently. Probiotics recently have become a subject of great interest in the field of microbiology, especially their role in normal physiology and its impact on human health during infection. The utilization of probiotics has prompted promising outcomes in countless well-designed clinical studies. For example, as a therapeutic option for the treatment, forestall and control of various disorders and illnesses like, gastrointestinal diseases, allergy, urogenital infections, Helicobacter pylori infection, inflammatory bowel syndrome and diarrhea and colon cancer. Currently, it has become one of the fruit full and attractive research area as it can prevent and treat communicable and non-communicable human diseases. Different clinical study outcome supports this idea. The results of such extensively studied and explored could demonstrate the improvement of health and quality of life. Their prospective potential application is in functional foods for better health and nutrition of the society
Q) Microbial stabilility in Probiotics.
ReplyDeleteAns : Factors include
1) The physiologic state of the probiotic organisms added (cells are from the logarithmic or the stationary growth phase),
2) The physical conditions of product storage (eg, temperature),
3) The chemical composition of the product to which the probiotics are added (eg, acidity, available carbohydrate content, nitrogen sources, mineral content, water activity, and oxygen content),
4) Possible interactions of the probiotics with the starter cultures (eg, bacteriocin production, antagonism, and synergism).
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Ques. Do milk contain sugar?
ReplyDeleteAns. Yes, milk contains naturally occuring sugar called lactose. It gives milk a slightly sweet taste. The body breaks lactose to glucose and galactose. This process is important because glucose is the primary source of energy in body and sole energy source of brain.
Lactose, makes up around 0-8% of milk by weight.
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Ques- what is the difference between probiotics and prebiotics?
ReplyDeleteAns:- Probiotics are types of ‘living’ friendly bacteria similar to those that inhabit our digestive tract. They are naturally found in cultured or fermented foods such as yoghurt, buttermilk, aged cheese, sauerkraut, sourdough bread, miso, tempeh and kombucha a type of fermented tea and can also be taken in supplement form. Probiotics help to maintain healthy levels of good bacteria in the intestines, they support our immune defences, are useful for anyone suffering from the uncomfortable symptoms of bloating, gas or flatulence and may assist in decreasing the duration of diarrhoea in kids. They may also help to restore good bacteria after a course of antibiotics. There are many different types of probiotics and each behaves a little differently. You might be familiar with lactobacillus acidophilus and bifidibacterium lactis, which are often found in yoghurt.
Prebiotics are ‘non‐living’ food ingredients that reach the large intestine unaffected by digestion, and ‘feed’ the good bacteria in our gut helping them to grow and flourish. Prebiotics such as fructooligosaccharides (FOS) and galacto‐oligosaccharides (GOS) are naturally found in many foods including:
Legumes
Whole wheat products
Rye based foods
Artichokes
Onions
Cabbage
Garlic
Chicory root
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Oue-Bacterial species present in
ReplyDeletecurd??
Ans-Lactobacillus casei
Lactobacillus acidophilus
Lactobacillus bulgaricus
Lactobacillus delbrueckii
Streptococcus thermophilus
Streptococcus salivarius
Bifidobacterium bifidum
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Question:- why E.coli is used as a model organism?
ReplyDeleteAns:-
▪ Escherichia coli, the enteric bacterium, is an ever-present constituent of all human beings and form a fraction of the normal flora of gut.
▪E. coli is a single-celled organism that can be manipulated and killed with no ethical concerns.
▪ It has a rapid growth rate and is very easy to culture in laboratory.
The E. coli can survive in uneven growth conditions including uneven temperatures, oxygen content, and nutrient availability.
▪Because of their comparative simplicity, prokaryotic cells(bacteria) are ideal models for studying many fundamental aspects of biochemistry and molecular biology.
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Question:- list of bacterial species present in Yogurt.
ReplyDeleteAns:-
Many different bacteria can be found in yogurt, but all yogurts have to contain the bacteria Lactobacillus bulgaricus and Streptococcus thermophilus. These strains of lactobacillus and streptococcus are examples of good bacteria. Other bacteria that you may find in yogurt that are also examples of good bacteria include:-
Bifidobacterium animalis
Bifidobacterium bifidum
Bifidobacterium lactis
Bifidobacterium longum
Enterococcus faecium
Lactobacillus acidophilus
Lactobacillus casei
Lactobacillus delbrueckii
Lactobacillus johnsonii
Lactobacillus gasseri
Lactobacillus plantarum
Lactobacillus rhamnosus
Saccharomyces boulardii
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How is Candida albicans spread?
ReplyDeleteAns:
Candida albicans is usually transmitted from mother to infant through childbirth, and remains as part of a normal human's microflora. The overgrowth of C. albicans leads to symptoms of disease, and it occurs when there are imbalances – for example, changes in the normal acidity of the vagina.
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What foods kill Candida?
ReplyDeleteAns:Foods that are okay on the candida diet are green vegetables, meat, fish, eggs, salad, almonds, walnuts, herbal tea, green juice, and unsweetened coconut water. Along with the diet, he suggests taking vitamins and a probiotic, getting enough sleep, and avoiding stress, which all help boost your immune system.
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Why is LPS a virulence factor?
ReplyDeleteAns:As a surface structure, LPS interacts with the host; host defense systems recognize a bacterium by the elicited immune responses to its LPS. Therefore, the LPS is an immunoreac- tive surface antigen. ... The LPS is therefore an important factor in the pathogenicity of infec- tions due to gram-negative bacteria.
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Qué: which bacterial spp. Present
ReplyDeletein chrd?
And:The species of bacteria used in yogurt are Streptococcus thermophilus and Lactobacillus bulgaricus.
Qué: which type of species present in curd?
ReplyDeleteAns: species of bacteria used in yogurt are Streptococcus thermophilus and Lactobacillus bulgaricus.
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ReplyDeleteQuestion:- why E.coli is used as a model organism?
Ans:-The E. coli genome is relatively small, 4.5 to 5.5 Mbp and simple when compared to our own (nearly 3 billion bp). Most strains of E. coli are harmless in contrast to the more headline grabbing strains such as 0157 or Verocytotoxin-producing E. coli (VTEC). Strains such as K12 are easily cultured with simple nutritional requirements and have a short generation time as low as ~20 minutes. Mutants are easily obtained using well established methods and screening techniques, which, has enabled many biochemical processes to be linked back to the molecular genetic level. Current research areas of interest for E. coli include acting as a vector, a host for genetic elements and synthesis of proteins of interest.
Question:- why E.coli is used as a model organism?
ReplyDeleteAns:Escherichia coli, the enteric bacterium, is an ever-present constituent of all human beings and form a fraction of the normal flora of gut.
▪E. coli is a single-celled organism that can be manipulated and killed with no ethical concerns.
▪ It has a rapid growth rate and is very easy to culture in laboratory.
The E. coli can survive in uneven growth conditions including uneven temperatures, oxygen content, and nutrient availability.
▪Because of their comparative simplicity, prokaryotic cells(bacteria) are ideal models for studying many fundamental aspects of biochemistry and molecular biology.
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Bacterial species present in
ReplyDeletecurd??
Ans:Lactobacillus casei
Lactobacillus acidophilus
Lactobacillus bulgaricus
Lactobacillus delbrueckii
Streptococcus thermophilus
Streptococcus salivarius
Bifidobacterium bifidum
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ReplyDelete18mmb021-zalak
Qué:How to measure skin pH?T
Ans:skin hydrogen potential (pH) is a measure of the hydrogen ion concentration [H+] in the watery solution present on the surface. This solution is obtained by adding water to the skin surface, which is a hydrophobic layer comprising of lipids. Some of the lipids (the free fatty acid) are amphiphilic. These amphiphilic free fatty acids release their H+ ions into the added water. The pH is therefore the measurement of their dissociation within the water applied on the skin surface.3 Since the skin is not an aqueous solution, the measured skin surface pH values are referred to as apparent pH values due to the extraction of water-soluble components of the stratum corneum into the liquid interface between the skin and the pH measuring system.
Flat pH electrodes, also called flat bottom pH electrodes, flat tip pH electrodes, and flat surface pH electrodes, were developed for measuring pH of surface skin. The use of flat pH electrode connected to a pH meter provides not only excellent contact with the skin but also measurement accuracy within ± 0.1 pH. This measurement is non-invasive and produces only small electric current causing no skin damage. Both the sensing membrane and reference junction of a flat pH electrode are constructed on the flat surface tip of the electrode body. This tip configuration is perfect for measuring pH of single drop or small volume of liquid samples as well as moist surfaces of soft solid or semi-solid samples such as meat, paper, skin, cloth, cheese, leaves, leather, bread dough, and culture media.
Riboswitch:In molecular biology, a riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA.
ReplyDelete18mmb003
Ques. Do mosquitoes spread HIV
ReplyDeleteAns. No, mosquitoes do not spread HIV because HIV acts by penetrating and hiding into the human T cells and these cell are absent in mosquitoes , therefore the HIV are exposed to the enzymes in the mosquito gut and these viruses are rapidly broken down there.
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Why can't mosquitoes transmit HIV?
ReplyDeleteDue to:
(1) only saliva is injected into humans when mosquito bites and thus HIV positive blood is never transmitted to other humans.
(2) HIV virus gets digested in the mosquito's gut.
In humans,HIV binds to T cells & replicate.no T cells exist inside mosquito gut.so virus has no way of Replication. HIV particles are digested by mosquito.
(3) HIV circulates at low levels in human blood.
Question: Is it possible for mosquitoes to spread HIV?
ReplyDeleteAnswer: Many reasons explained that mosquitoes cannot transmit this virus. First, because the AIDS virus cannot replicate in mosquitoes (or in other insects such as bed bugs or fleas elsewhere). Indeed, the AIDS virus needs to recognize the cells of the immune system to be able to infect them and then reproduce inside these cells. It binds and multiplies only in “T4 lymphocytes”, immune cells essential to humans but absent in insects. Unlike humans, mosquito cells do not have the surface receptors that allow the virus to penetrate, and thus the infection. The virus is digested and destroyed in the stomach of the mosquito. Mosquitoes cannot transmit this virus, since they have not been contaminated themselves.
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Q: why can't mosquitoes transmit HIV ?
ReplyDeleteA: 1: mosquitoes' blood-sucking mechanism-professor wayne crans of Rutgers university nicely puts it "mosquitoes are not flying hypodermic needles".
the "snout" of a mosquito, the part that looks like a needle, is actually composed of six mouthparts. out of two parts are composed of tubes.
one of the tubes sends saliva into the host and the other sends blood up to the mosquito.
this two tube system is one reason why mosquitoes are unable to transmit HIV.
only saliva is injected into humans when a mosquito bites and thus HIV positive blood that a mosquito may have previously injected is never transmitted to other humans.
2: the HIV virus gets digested in the mosquito's gut-HIV is unable to replicate in mosquito's gut and therefore is broken down. during the digestion process, the HIV particles are "completely destroyed".
3: HIV circulates at low level in human blood-HIV circulates in human blood at a far low level than would be necessary to creat a new infection.
if a mosquito were to inject HIV positive blood into a human (which, as evidenced by reason 1 & 2, is not possible) then it would take a whopping "ten million mosquito" bites to transmit one unit of HIV.
people who are HIV positive generally carry no more than "ten units" of HIV.
(www.nature.com)
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Q: can a person transmit HIV through kissing?
ReplyDeleteA: a person can transmit HIV through blood, semen, and breast milk. however, HIV can not survive in saliva, so there is no risk of contracting HIV through kissing.
-HIV can enter the body through damaged areas in the mucous membrane lining the vagina and the rectum.
-The mouth also contains mucous membrane, but they do not contain cells that are vulnerable to HIV, such as those presents in the vagina and rectum.
-saliva contains several proteins and enzymes that serve many different functions, such as beginning the digestion process, assisting in mouth lubrication, and even fighting off germs.
-secretory leucocyte protease inhibitor (SLPI) is an enzyme present in saliva, mucous, and seminal fluid.
-SLPI prevents HIV from infecting monocytes and T cells, which are types of WBC and part of the Immune system.
-saliva contains much higher concentration of SLPI than vaginal and rectal fluids. this may explain why HIV is mostly present in body fluids other than saliva.
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Q:- Can we get AIDS from mosquito bites?
ReplyDeleteAns:-Human immunodeficiency virus, or HIV, is a human retrovirus that infects lymphocytes and other cells bearing the CD4 surface marker. The virus is transmitted primarily by sexual and parental routes. There are two ways blood feeding arthropods can spread disease, mechanically, by simple transfer of virus between hosts by contaminated mouth parts, or, biologically, which would require virus replication in arthropod tissues (especially salivary glands). There are some important factors which have proven that AIDS is not transmitted by mosquito bite. These factors are: (1) AIDS virus can not replicate inside the mosquito, bed bug, flea, or other blood sucking insect and the lack of replication of HIV in arthropod cells due to lack of T4 antigen on cell surface, and (2) it is unlikely that HIV is transmitted by insects, given the low infectivity of HIV and the short survival of the virus in the mosquito. HIV appears to be much less easily transmitted probably due to lower titers of virus in body fluids.
Question:-If a used needle can transmit HIV, why can't a mosquito?
ReplyDeleteAns:-
The AIDS virus (HIV) on used needles is infectious when injected into a human where the virus can bind to T cells and start to replicate. The human T cell is a very specific host cell for HIV. When a mosquito feeds on a person with HIV in his or her blood, the HIV enters the insect's gut, which does not contain human T cells. The virus thus has no host cell in which to replicate and it is broken down by the mosquito's digestive system.
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Do mosquito bites spread HIV?
ReplyDelete->>There are some important factors which have proven that AIDS is not transmitted by mosquito bite.
These factors are:
(1) AIDS virus can not replicate inside the mosquito, bed bug, flea, or other blood sucking insect and the lack of replication of HIV in arthropod cells due to lack of T4 antigen on cell surface
(2) it is unlikely that HIV is transmitted by insects, given the low infectivity of HIV and the short survival of the virus in the mosquito.
The HIV virus circulates in the human body at considerably low levels. The quantity of blood a mosquito takes from a host is considerably small and it not enough for infestation.
It has been estimated that it would take around ten million mosquito bites for the virus to be transmitted to a single person. What is more, if you happen to accidentally swallow a mosquito that has bitten an HIV positive person, you are also safe, as the quantity of infected blood is considerably small.
Question : Do mosquitoes spread HIV ?
ReplyDeleteAnswer: No, Mosquitoes do not spread HIV, Because ,
1 ). Only saliva is injected into humans when a mosquito bites and thus HIV positive blood that a mosquito may have previously ingested is never transmitted to other humans.
2). The HIV virus gets digested in the mosquito's gut. HIV is unable to replicate within the mosquito's gut and therefore is broken down. In humans, HIV binds to T cells and begins replicating. No T cells exist inside the mosquito's gut and so the virus has no way of replicating or migrating to the mosquito's salivary glands. HIV particles are therefore digested by the mosquito alongside the actual blood meal.
3). it is unlikely that HIV is transmitted by insects, given the low infectivity of HIV and the short survival of the virus in the mosquito.
4). HIV circulates at low levels in human blood. In order for mosquito-borne diseases to be spread from person to person, the associated virus needs to circulate within the host's blood at sufficient levels. HIV circulates in human blood at a far lower level than would be necessary to create a new infection. If a mosquito were to inject HIV positive blood into a human , then it would take a whopping ten million mosquito bites to transmit one unit of HIV.
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Question : Can a person transmit HIV through kissing?
ReplyDeleteAnswer : A person cannot transmit HIV through kissing because the virus is not present in saliva. HIV can enter the body through damaged areas in the mucous membranes lining the vagina and the rectum.
The mouth also contains mucous membranes, but they do not contain cells that are vulnerable to HIV, such as those present in the vagina and rectum. Saliva carries minuscule traces of the virus, but this isn’t considered harmful.
Saliva contains enzymes that break down the virus before it has a chance to spread.
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Q:- Do milk contain sugar?
ReplyDeleteA:-sugar is a sweetener that provides calories and is added to food and drinks to give them a sweet taste, as well as texture, body and bulk. It is also sometimes called a caloric sweetener. Sugar is a simple carbohydrate that your body uses for fuel; it has no other nutritional level.
Lactose, also known as milk sugar, makes up around 0-8 percent of milk ,by weight.
Extracted from sweet or sour whey, lactose can be separated from milk, to create lactose free dairy products, and can be marketed and sold separately
Pure lactose is about 20 percent the sweetness of Cane sugar and is used in unique food applications and as a sweet addition to flavored milk.
One cup of white milk (250) contains 12 grams of naturally occurring sugar called lactose .it gives milk a slightly sweet taste. The body breaks lactose down into glucose and galactose.
This process is important because glucose is the primary source of energy in the body and sole energy source of brain.
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Q:- Microbial stability in probiotics
ReplyDeleteA:- Manufacturer of probiotic products involves industrial processes that reduce the viability of the strains The lost of viability constitutes an economic burden for manufacturers, compromising the efficacy of the product and preventing the inclusion of probiotics in many product categories.
Different strategies have been used to improve probiotic stability during industrial process .These include technological approaches such as the modification of production parameters or the re formulation of products, as well as microbiological approaches focused on the strain intrinsic resistance. Among the later, both selection of natural strains with desired properties and stress adaptation of strains have been widely used.
During recent years, the knowledge acquired on the molecular basis of stress - tolerance of probiotics has increased our understanding on their responses to industrial steesses.
This knowledge on stress response may nowadays be used. For the selection of the best strains and industrial conditions in terms of probiotic stability in the final product.
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Q :- Do mosquitoes spread HIV?
ReplyDeleteA:- Bryson noted how HIV, the agent behind the AIDS disease, is not transmissible by mosquitoes.
Mosquitoes are carriers for several infamous viruses, most notably malaria and dengue fever, In fact mosquitoes, through mosquito borne disease, kill more people per year than any other animal .luckily for humans, the HIV virus is not carried or spread by mosquitoes. Several reasons account for the inability of mosquitoes to transmit HIV.
1) Mosquitoes blood Sucking Mechanism
As professor Wayne Crans of Rutgers University so nicely puts it mosquitoes are not flying hypodermic needles. The snout of a mosquito, the part that looks like a needle ,is actually composed of six mouthparts. Two parts composed of two tubes. One of two tubes send saliva into the host and the other sends blood up to the mosquito .this two tubes system is one reason why mosquitoes are unable to transmit HIV. Only saliva is injected to the humans when a mosquito bites and thus HIV positive blood that a mosquito may have previously ingested is never transmitted to other humans.
2) The HIV virus gets digested in the mosquito's gut.
3) HIV circulates at low levels in human blood.
18mmb011.
Why do we feel cold when we have fever??
ReplyDelete- when brain increases body's temperature set point,body strives to meet that higher temperature.and we feel cold because technically we are colder than our body's new set point.
In turn, the body works to generate heat to warm itself by contracting & relaxing muscles so shivering and chills.
https://www.quora.com/Why-do-we-feel-cold-when-we-have-a-fever/answer/Parthiban-Bala?share=6a864aae&srid=lfEq
Question: Why do we feel chill during fever even if our body's temperature gets higher?
ReplyDeleteAnswer: When the brain increases the body's temperature set point, the body strives to meet that higher temperature. We feel cold because technically we are colder than our body's new set point. In turn, the body works to generate heat to warm itself by contracting and relaxing muscles — hence the shivering, or chills.
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Q: why do we feel cold even in a fever?
ReplyDeleteA:There is an internal thermostat in the hypothalamus. It regulates the temperature. For eg, if body temperature is above the level desired,then it activates certain mechanisms by which body temperature is brought down
In fever, either by toxins produced by pathogens, or cytokines/prostaglandins causes the internal thermostat to raise its temperature cutoff. So our brain starts to think that present body temperature is low and starts the mechanism to raise the body temperature. This causes fever.
Body can increase temperature by
1. producing heat (muscle contractions, shivering,
increased metabolism to produce heat)
2. reduce loss of heat (cutaneous vasoconstrictio
Here our brain is
tricked. When pyrogens reset the temperature cutoff at a higher level, brain starts to think that our temperature is low than normal, hence we feel cold.
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➡️Why do we feel cold and shiver when we have a fever?
ReplyDelete☆Even though fevers raise your internal temperature, you feel so cold because your body wants your insides to get even toastier.
A fever is when your body increases its internal thermostat, found in the hypothalamus. If you exercise hard or it’s a hot day, your body temperature might increase, but the thermostat remains at around 36.8°C. When you feel hot the hypothalamus tries to correct this with sweating and increased blood flow to the skin.
With a fever, it is actually the thermostat that has adjusted. This means your body temperature is now below 36.8°C, so you feel cold and shiver, to try and raise your temperature.
Problems with defining the indigenous microbiota of a body site:
ReplyDelete-technical problems due to complexity of the microbial community
generally only small numbers of samples can be processed – limits the statistical reliability of the data obtained
-difficulty in obtaining appropriate, uncontaminated samples from many body sites
-variations between individuals related to genotype, age, sex, diet, hygiene practices, health status, type of clothing, occupation, prevailing climate, etc.
-difficulties in comparing results obtained using different methodologies
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Riboswitch:
ReplyDeleteRiboswitches are structured RNA elements present in the 5’ untranslated regions of some mRNAs and regulate gene expression via pre-mature transcription termination or repression of translation initiation.
he typical riboswitch contains two distinct functional domains. The effector molecule is recognized by an aptamer domain.A second domain, the expression platform, interfaces with the transcriptional or translational machinery.Regulation is achieved by virtue of a region of overlap between these two domains, known as the switching sequence, whose pairing directs folding of the RNA into one of two mutually exclusive structures in the expression platform that represent the on and off states of the mRNA.
http://sites.lsa.umich.edu/walter-lab/wp-content/uploads/sites/94/2015/04/Riboswitch.jpg
Siderophore:
Iron is required by microbes for the function of their cytochromes and enzymes, resulting in it being a growth-limiting micronutrient. However, little free iron is available in environments, due to its insolubility. Many bacteria have evolved siderophores, organic molecules that chelate or bind ferric iron with high affinity. Siderophores are released by the organism to the surrounding environment, whereby they bind any available ferric iron. The iron-siderophore complex is then bound by a specific receptor on the outside of the cell, allowing the iron to be transported into the cell.
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How doyou feel cold when you have a fever?
ReplyDeleteThere is an internal thermostat in the hypothalamus (part of the brain). It regulates the temperature. For eg, if body temperature is above the level desired, then it activates certain mechanisms by which body temperature is brought down.
In fever, either by toxins produced by pathogens, or cytokines/prostaglandins causes the internal thermostat to raise its temperature cutoff. So our brain starts to think that present body temperature is low and starts the mechanism to raise the body temperature. This causes fever.
Body can increase temperature by
1. producing heat (muscle contractions, shivering, increased metabolism to produce heat)
2. reduce loss of heat (cutaneous vasoconstriction)
So why do we feel coldness. Here our brain is tricked. When pyrogens reset the temperature cutoff at a higher level, brain starts to think that our temperature is low than normal, hence we feel cold.
It is just a protective mechanism. Lets say we are exposed to cold. It would reduce our body temperature. When our body temperature is less than that of the thermostat, we would feel cold. If we feel cold we would take necessary measures to make us warm.
Here the problem is, our internal thermostat is rest, and hence our brain gets confused, and we feel cold.
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Q) Why do we shiver and feel cold during fever?
ReplyDeleteA) If your body temperature is higher than normal, the air and environment around you will feel colder than it usually does. When there is more of a difference between your body temperature and the temperature of your environment than usual, you will feel colder than you would otherwise.
1) During fever, cytokines and prostaglandins are released as part of the inflammatory response, which elevates the set point for body temperature in the hypothalamus. This causes the body temperature to rise and also makes the patient feel cold until the new set point is achieved.
2) Shivering also occurs along with chills because the patient's body produces heat during muscle contraction in a physiological attempt to increase body temperature to the new set point.
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(Surabhi Joshi)
☆What Is the Incubation Period Malaria?
ReplyDelete▪The incubation period between infection with malaria by a mosquito bite and initial symptoms may range from one week to one year. Generally, the incubation period ranges from nine to 14 days for P. falciparum, 12-18 days for P. vivax, and 18-40 days for P. ovale.
☆What Is the prepatent Period Malaria?
ReplyDelete> prepatent period is defined as the time between sporozoite inoculation and the appearance of parasites in the blood and represents the duration of the liver stage and the number of merozoites produced.
ReplyDeleteExoerythrocytic schizogony and prepatent and incubation periods
P. falciparum
P. vivax
P. ovale
P. malariae
Prepatent period (days)
6-9
8-12
10-14
15-18
Incubation period (days)
7-14
12-17
16-18
18-40
Merozoite maturation (days)
5-7
6-8
9
12-16
Merozoites produced
40,000
10,000
15,000
2000
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ReplyDeleteQues. Is milk contain sugars?
Ans. Yes, milk contains naturally occuring sugar called lactose.
It gives milk a slightly sweet taste. The body breaks lactose to glucose and galactose.
Lactose=Glucose+ Galactose
glucose is the primary source of energy in body and sole energy source of brain.
Lactose, makes up around 0-8% of milk by weight.
18mmb021- zalak patel
ReplyDeleteQ)Why do we feel cold and shiver when we have a fever?
A) There is an internal thermostat in the hypothalamus that regulates the temperature.
For eg, if body temperature is above the level desired, then it activates certain mechanisms by which body temperature is brought down.
In fever, either by toxins produced by pathogens, or cytokines/prostaglandins causes the internal thermostat to raise its temperature cutoff.
So our brain starts to think that present body temperature is low and starts the mechanism to raise the body temperature. This causes fever.
18mmb021-zalak patel
ReplyDeleteQue:What Is the prepatent Period Malaria?
Ans: The prepatent period is defined as the time between sporozoite inoculation and the appearance of parasites in the blood and represents the duration of the liver stage and the number of merozoites produced.
18mmb021-zalak patel
ReplyDeleteQ) what is riboswitching ?
A)In moleculer biology, a riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in production of the proteins encoded by the mRNA.
Thus, an mRNA that contains a riboswitch is directly involved in regulating its own activity, in response to the concentrations of its effector molecule. The discovery that modern organisms use RNA to bind small molecules, and discriminate against closely related analogs, expanded the known natural capabilities of RNA beyond its ability to code for proteins, catalyze reactions, or to bind other RNA or protein macromolecules.
The original definition of the term "riboswitch" specified that they directly sense small-molecule metabolite concentrations.
Although this definition remains in common use, some biologists have used a broader definition that includes other cis-regulatory RNAs.
18mmb021-zalak patel
ReplyDeleteQue-What you mean by Exoerythrocy schizogony?
Ans-The intracellular parasite undergoes an asexual replication known as exoerythrocytic schizogony within the hepatocyte.
Exoerythrocytic schizogony culminates in the production of merozoites which are released into the bloodstream.
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ReplyDeleteQuestion:-If use needle can transmit HIV, then why a mosquito can not?
Ans:-
The AIDS virus (HIV) on used needles is infectious when injected into a human where the virus can bind to T cells and start to replicate.
The human T cell is a very specific host cell for HIV.
When a mosquito feeds on a person with HIV in his or her blood, the HIV enters the insect's gut, which does not contain human T cells.
The virus thus has no host cell in which to replicate and it is broken down by the mosquito's digestive system.
18mmb021-zalak patel
ReplyDeleteQuestion:-If a needle can transmit HIV, then why a mosquito can not?
Ans:-
Reasons are many but most appropriate is mentioned here.
AIDS virus (HIV) on used needles is infectious when injected into a human where the virus can bind to T cells and start to replicate.
The human T cell is a very specific host cell for HIV.
When a mosquito feeds on a person with HIV in his or her blood, the HIV enters the insect's gut, which does not contain human T cells.
The virus thus has no host cell in which to replicate and it is broken down by the mosquito's digestive system.
Can we get AIDS from mosquito bites?
ReplyDeleteAns:When a mosquito feeds on a person with HIV in his or her blood, the HIV enters the insect's gut, which does not contain human T cells.
The virus thus has no host cell in which to replicate and it is broken down by the mosquito's digestive system.
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How do youfeelcold when you have a fever?
ReplyDeleteAns:Even though fevers raise your internal temperature, you feel so cold because your body wants your insides to get even toastier.
A fever is when your body increases its internal thermostat, found in the hypothalamus. If you exercise hard or it’s a hot day, your body temperature might increase, but the thermostat remains at around 36.8°C. When you feel hot the hypothalamus tries to correct this with sweating and increased blood flow to the skin.
With a fever, it is actually the thermostat that has adjusted. This means your body temperature is now below 36.8°C, so you feel cold and shiver, to try and raise your temperature.
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18mmb021- zalak patel
ReplyDeleteQue: Name the mosquito larvae eating fish.
Ans: Generally 'Gambusia affinis (gambezi)' used as larvae eating fish.
.In addition to goldfish, mosquito fish, minnows, koi and guppies eat mosquito larvae.
How can we know the pH of skin ?
ReplyDelete•Moisten the skin surface by applying one or two drops of distilled / deionized water or physiological saline.
•Place the flat pH electrode on the moist skin surface with a slight pressure to measure pH. Avoid excessive pressure on the electrode because this could influence the extraction of material from epidermis’ stratum corneum and may exclude water between the skin and the pH electrode membrane.
•Record the pH and temperature displayed on the meter once stable.
•After measurement, rinse the tip of pH electrode with distilled or deionized water and blot dry with soft tissue.
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What Is the prepatent Period Malaria?
ReplyDeleteAns:The prepatent period is defined as the time between sporozoite inoculation and the appearance of parasites in the blood and represents the duration of the liver stage and the number of merozoites produced.
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Que:How to measure skin pH?
ReplyDeleteAns:The skin hydrogen potential (pH) is a measure of the hydrogen ion concentration [H+] in the watery solution present on the surface. This solution is obtained by adding water to the skin surface, which is a hydrophobic layer comprising of lipids. Some of the lipids (the free fatty acid) are amphiphilic. These amphiphilic free fatty acids release their H+ ions into the added water. The pH is therefore the measurement of their dissociation within the water applied on the skin surface.Since the skin is not an aqueous solution, the measured skin surface pH values are referred to as apparent pH values due to the extraction of water-soluble components of the stratum corneum into the liquid interface between the skin and the pH measuring system.
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Why do we feel cold in fever instead of hot, sweating ?
ReplyDeleteThe internal thermostat malfunction is actually the body's way of fighting infection.Viruses and bacteria multiply less well above 98.6 degrees Fahrenheit. Part of our immune system's response against infection includes raising the body's temperature to diminish the ability of microbes to reproduce. A fever, or rise in body temperature, of even just a degree or two can stop a virus's ability to grow.
When the brain increases the body's temperature set point, the body strives to meet that higher temperature. We feel cold because technically we are colder than our body's new set point. In turn, the body works to generate heat to warm itself by contracting and relaxing muscles hence leads to shivering or chills.
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Top 5 selling drugs of 2017/18.
ReplyDeleteDrug (Trade name)
Adalimumab (Humira) - rheumatoid arthritis.
Apixaban (Eliquis) - anticoagulant.
Lenalidomide (Revlimid) - multiple myeloma.
Nivolumab (Opdivo) - oncology.
Pembrolixumab (Keytruda) - oncology.
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Q: Scientific name of fish used for eradication of mosquito larvae.
ReplyDeleteA: mosquito fish (Gambusia affinis),other fish groups like cyprinodontids (i.e. Aphanius species), tilapia and minnows will also eat mosquito larvae.
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Patients of HIV in India ?
ReplyDeleteAccording to UNAIDS,
India has the third largest HIV epidemic in the world, with 2.1 million people living with HIV.
In 2017, HIV prevalence among adults (aged 15-49) was estimated 0.2% because of India's huge population (1.3 billion people) this equates to 2.1 million people living with HIV.
Between 2010 and 2017 new infections declined by 27% and AIDS-related deaths more than halved, falling by 56%. However, in 2017, new infections increased to 88,000 from 80,000 and AIDS-related deaths increased to 69,000 from 62,000.
In 2017, 79% of people living with HIV were aware of their status, of whom 56% were on antiretroviral treatment (ART). The proportion of people on ART who are virally suppressed is not reported.
The HIV epidemic in India is driven by sexual transmission, which accounted for 86% of new infections in 2017/2018.
In 2017, an estimated 1.6% of female sex workers in India were living with HIV.
HIV prevalence among transgender people in India was estimated to be 3.1% in 2017, the second highest prevalence among all key populations in the country.
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(Q) Why do we get chills during fever??
ReplyDeleteA fever or rise in body temperature, of even just a degree or even two can stop the ability of bacteria or virus to grow .
When brain increases body's temperature set point,the body strives to meet that higher temperature.we feel cold because technically we are colder than our body's new set point.In turn the body works to generate heat to warm itself by contracting and relaxing muscles hence shivering or chills occurs.
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(Q) Fish which are use for the eradication of mosquito larvae??
ReplyDelete(1) Aphanius dispar (Dispar topminnow)
(2) Aplocheilus blockii (Dwarf
punchax)
(3) Colisa fasciatus (Giant gourami )
(4) Colisa lalia (Dwarf gourami)
(5) Chanda mama (Elongate glass
perchlet
(6) Oryzias melastigma ( Estuarine
ricefish
(7) Fabio rerio (Zebra Fabio)
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Q-fish used for eradication of mosquito larvae??
ReplyDelete(1) Heterandria affinis
(2) H.formosa
(3) Gambusia holbrooki (true mosquito
fish)
(4) Poecilia riticulata (Guppy)
Q Name the fish eating mosquito larvae
ReplyDeleteA Gambusia affinis is the mosquitofish that is classified as larvivorous fish and their diet consists of insect larvae. They feed on mosquito larvae at all stages of life.
Q Can mosquito spread HIV?
ReplyDeleteA Mosquito bite is unable to spread HIV due to different factors like:
1) AIDS virus cannot replicate inside the mosqito and lack of replication of HIV in arthropod cells.
2) Low infectivity of HIV and short survival of virus in mosquito.
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>>Malaria transmission in India
ReplyDeleteIndia is co-endemic for Plasmodium falciparum and P. vivax malaria and both have biological characteristics that impede malaria elimination efforts. While P. vivax is known for its repeated relapsing fever episodes/extended morbidity, the proportion of malaria cases caused by P. falciparum has risen with each passing year from 29% in 1985 to nearly 65% in 2016.
Nevertheless, unlike Africa, malaria transmission in India is by and large low-to-moderate and parasite distribution is heterogenous across its landscape. Invariably, focal disease outbreaks and malaria-attributable death cases (spread across all age groups of both sexes) are attributed to P. falciparum. In these foci malarial morbidity is enormous amidst public panic and chaos, so much so that the healthcare facilities are often beyond their carrying capacity. The majority of P. falciparum cases (80%) are contributed by just 20% of the population of a few states of the east, east-central and north-east India annually. These are also the states with large forest reserve and tribal/marginalized population groups living under impoverished conditions little aware of disease prevention and cure.
>Emergence and spread of drug-resistant malaria in India:
ReplyDeleteDrug-resistant malaria was first documented in 1973 in the north-east (NE) of India, sharing a contiguous border with other South-East Asian countries having similar ecology and disease transmitting vector species. Since then, drug-resistant parasite strains have multiplied, grown mono-to-multi- resistant and spread across India over space and time. P. falciparum is presently resistant to chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) in large tracts of peninsular India, resulting in rollout of artemisinin-based combination (ACT) therapies as first line treatment for their proven efficacies.
Worryingly, declining therapeutic efficacy to the chosen ACT therapy, i.e., artesunate + sulfadoxine-pyrimethamine (AS+SP) has surfaced in NE India, which is considered to be the corridor for spread of drug-resistant varieties emanating from Cambodia to the rest of India and westwards.
Consequently, AS+SP combination now has been replaced with artemether-lumefantrine (AL) specific to NE India. Alarmingly, there are already reports of emerging artemisinin resistance in Myanmar close to Indian border and it’s spread to NE, evidenced by prevalence of ‘kelch-13’ a molecular marker closely linked with this phenomenon presenting every possibility of its spread in India and beyond.
Q:- why do we feel cold and shiver when we have fever?
ReplyDeleteA:- The reason is that when we are ill, there are chemicals being produced in our body causing our brain to reset the body's internal thermostat at a higher temperature. So, the new normal requires our body to feel cold even if our temperature is above 98.6 but below the new higher setting Our body reacts with chills or muscle contraction, which are designed to increase our body's temperature many illness can cause the release of pyroxene, which are chemicals raising the brain thermostat setting. But this occur with infections like flu.
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Question, . Why Do We Get the Chills When We Have a Fever?
ReplyDeleteAnswer , When you are ill, there are chemicals being produced in your body causing your brain to reset the body’s internal thermostat at a higher temperature. So, the new ‘normal’ requires your body to feel ‘cold’ even if your temperature is above 98.6 but below the new higher setting. Your body reacts with ‘chills,’ or muscle contractions, which are designed to increase your body’s temperature.
Body can increase temperature by
1. producing heat (muscle contractions, increased metabolism to produce heat)
2. reduce loss of heat (cutaneous vasoconstriction)
Many illnesses can cause the release of pyrogens, which are chemicals raising the brain’s thermostat setting. But commonly this occurs with infections like the flu.
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Question : What Is the prepatent Period Malaria?
ReplyDeleteAnswer : It is the time in between sporozoite inoculation and the appearance of parasites in the blood and represents the duration of the liver stage and the number of merozoites produced. ... Sometimes the incubation periods can be prolonged for several months in P. vivax, P. ovale, and P. malariae.
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Question : HIV and AIDS in India
ReplyDeleteAnswer: India has the third largest HIV epidemic in the world. In 2017, HIV prevalence among adults (aged 15-49) was an estimated 0.2%. This figure is small compared to most other middle-income countries but because of India's huge population (1.3 billion people) this equates to 2.1 million people living with HIV
Overall, India’s HIV epidemic is slowing down. Between 2010 and 2017 new infections declined by 27% and AIDS-related deaths more than halved, falling by 56%. However, in 2017, new infections increased to 88,000 from 80,000 and AIDS-related deaths increased to 69,000 from 62,000
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Question: The global scenario of Malaria
ReplyDeleteAnswer: I n 2017, 86 countries repoted a total of 219 million malaria cases and 435, 000 malaria deaths, down from 262 million cases and 839,000 deaths in 2000.
However, cases and deaths were not distributed evenly. The heartening news was 38 countries had incidences of fewer than ten cases per 1,000 population in 2017 and 25 countries reported fewer than one case per 1,000 population.
But the most troubling news was all 29 countries that reported more than 100 cases per 1,000 population were in Africa except Papua New Guinea and the Solomon Islands.
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