1) Probiotics = probiotics are live microbial feed supplements which beneficially affect the host by improving microbial balance.
2) prebiotices = A selectively fermented ingredient that results in specific changes in the composition of the gastrointestinal microbiota, thus conferring benefits upon host health.
3) Postbiotices = Postbiotices are non viable bacterial or metabolic products from microorganisms that have biological activity in the host, probiotics feed on prebiotics, postbiotics are produced.
4) Synobiotics = Synobiotics are defined as synergistic mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and colonization of live benefical microorganism in the gastrointestinal tract of the host.
The gut-brain axis (GBA) is a bidirectional link between the central nervous system (CNS) and the enteric nervous system (ENS) of the body. It involves direct and indirect pathways between cognitive and emotional centres in the brain with peripheral intestinal functions.
The communication between the CNS and the intestine, and it happens through microbiota so it is called Gut-Brain Axis.
germ-free mice treated with antibiotics for reduce the microbial diversity within the intestine, showed that several neurological problems occur in mice with reduced proper gut microbiota.
microbes can produce neuroactive molecules that directly contribute to the communication between the gut and the brain.
Example : Neurotransmitters, like acetylcholine, and serotonin, produced by bacteria belonging to Lactobacillus, Bifidobacteria, Enterococcus, and Streptococcus species, it can influence brain cell physiology.
Another example microbial metabolite that influences microglia activity is tryptophan, The importance of tryptophan metabolism in maintaining CNS homeostasis. Hemostasis is the mechanism that leads to cessation of bleeding from a blood vessel.
The gut–brain axis is a bidirectional communication system between the central nervous system (CNS) and the GI tract. Regulation of the microbiota–brain–gut axis is essential for maintaining homeostasis, including that of the CNS. A number of approaches have been used to probe this axis, including the use of germ-free animals, probiotic agents, antibiotics, or animals exposed to pathogenic bacterial infections.
The communication between the CNS and the intestine, and it happens through microbiota so it is called Gut-Brain Axis.
germ-free mice treated with antibiotics for reduce the microbial diversity within the intestine, showed that several neurological problems occur in mice with reduced proper gut microbiota.
microbes can produce neuroactive molecules that directly contribute to the communication between the gut and the brain.
The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions.
1.Primary colonization: Microorganisms comes and sitting on the surface of body it's called primary colonization. 2.secondary colonization:when that organisms adapte that conditions and establishes their colony on the surface it's called secondary colonization. 3.Neutraceuticals: It's products, which other than nutrition are also used as medicine. A nutraceutical product may be defined as a substance, which has physiological benefit or provides protection against chronic disease.
Succession-after the secondary colonization, the established colony evolves over time by some structural changes,
Climax community-it is the final stage of succession where the community is largely stable.
And Resiliance-it is the capacity to recover any function of interest after it has been completely or partially lost due to any kind of disturbance, (like some catastrophic events) These are the stages how microbio e changes.
1.) Microbiome refers to microbes host elements such as epithelium, immune components and their products.The human microbiome comprises bacteria, archaea, viruses and eukaryotes which resides within and outside our bodies These organisms impact human physiology both in health and in disease, contributing to enhancement or impairment of immune functions.
2.) Gut Dysbiosis is defined as an imbalance in the gut microbial community that is associated with disease. Some effects of dysbiosis, such as stomach upset, are temporary and mild. In many cases, your body can correct the imbalance without treatment.
3.) Gut–brain axis is the relationship between the GI tract and brain function and development and broadly it is defined, the gut–brain axis includes the central nervous system, neuroendocrine and neuroimmune systems, including the hypothalamic–pituitary–adrenal axis (HPA axis), sympathetic and parasympathetic arms of the autonomic nervous system, including the enteric nervous system and the vagus nerve, and the gut microbiota. The first of the brain–gut interactions shown, was the cephalic phase of digestion, in the release of gastric and pancreatic secretions in response to sensory signals, such as the smell and sight of food. This was first demonstrated by Pavlov. Interest in the field was sparked by a 2004 study showing that germ-free (GF) mice showed an exaggerated HPA axis response to stress compared to non-GF laboratory mice. As of October 2016, most of the work done on the role of gut flora in the gut–brain axis had been conducted in animals, or on characterizing the various neuroactive compounds that gut flora can produce.And the studies with humans is measuring variations in gut flora between people with various psychiatric and neurological conditions or when stressed, or measuring effects of various probiotics (dubbed "psychobiotics" in this context) – had generally been small and were just beginning to be generalized. Whether changes to gut flora are a result of disease, a cause of disease, or both in any number of possible feedback loops in the gut–brain axis, remained unclear.
4.) Colonization resistance was first identified in 1967, and it was initially referred to as antibiotic associated susceptibility. It was observed that animals being treated with the antibiotic streptomycin were susceptible to Salmonella enterica at doses 10,000 fold lower than the standard minimal infectious dose.
4.) Probiotics are beneficial bacteria found in certain foods or supplements.
5.) Prebiotics are like the food, probiotics are the microorganisms themselves, and postbiotics are the results of probiotics consuming that food.
6.) Postbiotics are byproducts of the fermentation process carried out by probiotics in the intestine. In other words as probiotics feed on prebiotics, postibiotics are produced Although we normally thing of waste as bad probiotics are responsible for multiple important health- boosting functions in our gut.
7.) Synbiotics are mixtures of probiotics helpful gut bacteria and prebiotics non-digestible fibers that help these bacteria grow. Specifically, they're combinations of these two things that work together (synergistically) in your digestive tract.
8.) Climax community is one that has reached the stable stage. When extensive and well defined, the climax community is called a biome examples are tundra, grassland, desert, coniferous, and tropical rain forests.
9.) Communicable disease means an illness caused by an infectious agent or its toxins that occurs through the direct or indirect transmission of the infectious agent or its products from an infected individual or via an animal, vector or the inanimate environment to a susceptible animal or human host,Some examples of the communicable disease include HIV, hepatitis A, B etc.
10.) Non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another,Some examples of the NCDs include Parkinson's disease, autoimmune diseases, strokes, heart diseases, cancers, diabetes, chronic kidney diseases, Alzheimer's disease are collectively responsible for almost 70% of all deaths worldwide.
Bacterial phyla that reduce or regulate intestinal inflammation, such as Bacteroidetes (e.g., Bacteroides fragilis), Firmicutes (e.g., Lactobacillus, F. prausnitzii and Clostridium strains), and Actinobacteria (e.g., Bifidobacterium), are reduced in IBD. Reference: https://doi.org/10.1016/B978-0-12-384931-1.00004-0
Tissue tropism : It is the range of tissues which can support the growth of a particular microorganism (commonly bacteria and viruses). Some microbes have a broad tissue tropism and can infect many types of cells and tissues while other may infect primarily a single tissue.
Psychobiotics : are beneficial bacteria (probiotics) or support for such bacteria (prebiotics) that influence bacteria–brain relationships. Psychobiotics exert anxiolytic and antidepressant effects characterised by changes in emotional, cognitive, systemic, and neural indices. Bacteria–brain communication channels through which psychobiotics exert effects include the enteric nervous system and the immune system.
Law of Minimum : Given by Liebig, states 1 that growth is controlled not by the total of resources available, but by the scarcest resource (limiting factor).
Law of Tolerance : Given by Shelford, states that the abundance or distribution of an organism can be controlled by certain factors (e.g. the climatic, topographic, and biological requirements of plants and animals) where levels of these exceed the maximum or minimum limits of tolerance of that organism.
What are Nutraceuticals ? Nutraceuticals are products, which other than nutrition are also used as medicine. A nutraceutical product may be defined as a substance, which has physiological benefit or provides protection against chronic disease. Nutraceuticals may be used to improve health, delay the aging process, prevent chronic diseases, increase life expectancy, or support the structure or function of the body. Nowadays, nutraceuticals have received considerable interest due to potential nutritional, safety and therapeutic effects.
Nutraceutical” is a substance that may be considered a food or part of a food which provides medical or health benefits, encompassing prevention and treatment of disease. Products as diverse as isolated nutrients, dietary supplements and diets to genetically engineered “designer” foods, herbal products, and processed foods (cereals, soups, beverages) may be included under the umbrella of nutraceuticals. In India, nutraceuticals have been defined under Clause 22 of the Food Safety and Standards Act (FSSA), 2006. This chapter describes the role of nutraceuticals in health and how they are different from functional foods and dietary supplements.
Nutraceutical” is a substance that may be considered a food or part of a food which provides medical or health benefits.
Nutraceuticals are used to improve health, delay the aging process, prevent chronic diseases, increase life expectancy, or support the structure or function of the body.
Nutraceutical products can be considered non-specific biological therapies used to promote general well-being, control symptoms, and prevent malignant processes.
The term “nutraceutical” combines the two words of “nutrient,” which is a nourishing food component, and “pharmaceutical,” which is a medical drug. The definition of nutraceuticals and their related products generally depends on the source. These products can be classified on the basis of their natural sources, pharmacological conditions, as well as chemical constitution of the products. Most often, nutraceuticals are grouped into four categories that include dietary supplements, functional food, medicinal food, and farmaceuticals.
What are the emulsifiers/food emulsifiers/dietary emulsifiers ? How they affect human gut microbiota ? Emulsifiers are a class of food additives used in food processing to alter the flavor, improve the texture, stability, and shelf-life of foods. Structurally, emulsifiers contain both hydrophobic and hydrophilic moieties that allow them to exist in both water and lipid fractions, thereby creating a consistent, homogenous mixture of immiscible liquids. Without emulsifiers, food products such as salad dressings, chocolate bars, mayonnaise, yogurt, and ice cream would not exist. Examples of commonly used emulsifiers include CMC, P80, arabinogalactan, carrageenan, and gum arabic. Emerging evidence suggests that permitted dietary emulsifiers may impact on gut health through impairing intestinal barrier function, thus increasing antigen exposure, and/or by modulating the microbiota, thus potentially increasing the incidence of inflammatory bowel disease (IBD) and metabolic syndrome.
Emulsifier, in foods, any of numerous chemical additives that encourage the suspension of one liquid in another, as in the mixture of oil and water in margarine, shortening, ice cream, and salad dressing. A number of emulsifiers are derived from algae, among them algin, carrageenan, and agar. Lecithins, such as those found in egg yolk, are also used as emulsifying agents.
The use of additives in food products has become an important public health concern. In recent reports, dietary emulsifiers have been shown to affect the gut microbiota, contributing to a pro-inflammatory phenotype and metabolic syndrome.
A food emulsifier, also called an emulgent, is a surface-active agent that acts as a border between two immiscible liquids such as oil and water, allowing them to be blended into stable emulsions. Emulsifiers also reduce stickiness, control crystallization and prevent separation. Emerging evidence suggests that permitted dietary emulsifiers may impact on gut health through impairing intestinal barrier function, thus increasing antigen exposure, and/or by modulating the microbiota, thus potentially increasing the incidence of inflammatory bowel disease (IBD) and metabolic syndrome.
Terms of Tissue tropism, Law of tolerance, Law of medium has nothing do specific with human microbiome they are applicable in general to wild ecological concepts including human microbiome ecosystem.
Tissue tropism indicates the certain species they will always found associate with certain tissues like Staphylococcus will associate with nasal cavity so the specific organism present at specific organ or in other words a given tissue support colonization has certain types of organization only this is known as tissue tropisum. Now this tissue tropisum is a result of the two situation which can explain by two laws first is law of tolerance and second law of minimum.
Law of Tolerance suggest that at any particular site only those organism survive who can tolerate the physochemical situation existing at that body site Eg:- Stomach has ph acidic food so only those orgamism can survive who can tolerate this they could survive there similarly with large intestine it is obligate anaerobic condition so only the organisms who can tolerate absence of oxygen they can survive there.
Law of Minimum tells any site which can provide the nutritional requirements of the organism of the particular type only those organism can find there.
Functional redundancy in soil microbial communities seems to contradict the notion that individual species have distinct metabolic niches in multi-species communities. All soil microbiota have the metabolic capacity for “basic” functions, but only a few soil microbiota participate in “rare” functions. The objective of this perspective paper is to use the phylogenetic niche conservatism theory as an explanation for the functional redundancy of soil microbiota. Reference: https://doi.org/10.1016/S1002-0160(19)60826-X
Although the taxonomic composition of the human microbiome varies tremendously across individuals, its gene composition or functional capacity is highly conserved — implying an ecological property known as functional redundancy. The human microbiome harbors a plethora of taxa carrying distinct genes and gene families1, making it functionally diverse. At the same time however, the human microbiome is functionally redundant, with many phylogenetically unrelated taxa carrying similar genes and performing similar functions. For example, dietary carbohydrates can be metabolized by either Prevotella (from the phylum Bacteroidetes) or Ruminococcus (from the phylum Firmicutes).
A characteristic of species within an ecosystem where certain species contribute in equivalent ways to an ecosystem function such that one species may substitute for another.
The human microbiome's taxonomic composition varies greatly between individuals, but its gene composition or functional capability is highly preserved, implying functional redundancy as an ecological feature. The origin of functional redundancy, which is thought to underpin the human microbiome's stability and resilience, has yet to be discovered.
Psychobiotics interacts with gut microbial community and it alters the microbiome in such a way that release the happy hormones..In other word it helps to fight with anxiety,mood disorder, depression, etc.
Psychobiotics are a group of probiotics that affect the central nervous system (CNS) related functions and behaviors mediated by the gut-brain-axis (GBA) via immune, humoral, neural, and metabolic pathways to improve not only the gastrointestinal (GI) function but also the antidepressant and anxiolytic capacity. As a novel class of probiotics, the application of psychobiotics has led researchers to focus on a new area in neuroscience. In the past five years, some psychobiotics strains were reported to inhibit inflammation and decreased cortisol levels, resulting in an amelioration of the symptoms of anxiety and depression. Psychobiotics are efficacious in improving neurodegenerative and neurodevelopmental disorders, including autism spectrum disorder (ASD), Parkinson's disease (PD) and Alzheimer's disease (AD). Use of psychobiotics can improve GI function, ASD symptoms, motor functions of patients with PD and cognition in patients with AD. However, the evidence for the effects of psychobiotics on mental and neurological conditions/disorders remains limited. Further studies of psychobiotics are needed in order to determine into their effectiveness and mechanism as treatments for various psychiatric disorders in the future.
psychobiotics is gut microbes which shows promise in treating mental health problems such as depression and anxiety.
these bacteria are capable of producing and delivering neuroactive substances such as gamma-aminobutyric acid and serotonin, which act on the brain-gut.
Lactobacillus helveticus and Bifidobacterium longum have both been found to be good probiotics for brain health, and for anxiety.
Psychobiotics were previously defined as live bacteria (probiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria.
The HPA axis is a term used to represent the interaction between the hypothalamus, pituitary gland, and adrenal glands, it plays an important role in the stress response.
The hypothalamic–pituitary–adrenal (HPA) axis is considered to be the major neuroendocrine system regulating various body processes in response to psychological stressors and physical stressors, including infections, ensuring an adequate response to the stressor. Emerging evidence points to a bidirectional communication between the neuroendocrine system and gut microbiota.
The main function generally attributed to the HPA axis involves the body's reaction to stress. When something stressful happens to us, our initial response is mediated by the sympathetic nervous system. This response occurs almost immediately, and results in the secretion of epinephrine and norepinephrine, both of which work to enact changes that you would generally expect if you felt stressed and/or frightened, like increased heart rate and perspiration.
The hypothalamic pituitary adrenal (HPA)axis is central stress response system. The HPA axis is intertwining of the central nervous system and endocrine system. The HPA axis is responsible for the neuroendocrine adaptation component of the stress response
What are enterotypes? Enterotypes are clusters of bacterial communities in the gut that allow researchers to identify common traits that bring people together. They are associated with specific long-term eating patterns.
Enterotypes are stable clusters of bacterial communities that co-exist together. These clusters do not have strict borders. Rather, they are fluid and distinguished by a dominant bacterial community within the person’s microbiome.
A classification of living organisms based on the bacteriological composition of their gut microbiota is known as an enterotype. Peer Bork and his colleagues revealed the discovery of three human enterotypes in the April 2011 issue of Nature. They discovered that age, gender, body weight, or country divides have no bearing on enterotypes. There is evidence that long-term diet has an impact on enterotype.
Enterotypes are shaped in large part by the particular long-term dietary habits of every individual for example, protein and fat-rich diets favor the proliferation of bacteria of the Bacteroides genus.
Q When a pathogenic E.coli enters our body our immune system most of the time it produces antibodies but when the same E.coli is present in the GI tract as a part of our normal human microbiome then our body is unable to recognize it why?
Ans- TLRs recognize microbes by binding to pathogen-associated molecular patterns. Toll-like receptors are components of the innate immune system that respond to exogenous infectious ligands (PAMPs) and endogenous molecules that are released during host tissue injury/death (damage-associated molecular patterns, DAMPs). Our immune system does not respond to the pathogenic E.coli in our GI tract as the microbe is currently not harming or damaging any tissues or not causing any inflammatory response in the human body. Since, it is an opportunistic pathogen is will not always harm our body. But if it turns out to be damaging the body, the immune system will recognize it and form antibodies against it.
Q. If we want to prove that particular group or species they are responsible for diabetes or obesity what kind of experiment we can do to prove this?
Ans. We can use germ free mice for such purpose germ free mice means gnotobiotic mice which are free from any microbiota of their own. Like Suppose that the mixer of A, B and C that is associate with obesity , Take a mixer of A, B and C then inject to germ free mice and then on those mice develop obesity you concluding say that the present of these three microbiome will make a person more to obesity this is a straight forward example but then negative result In case of negative result in such experiment the interpretation become more truth because in real life the microbiome is not made up of two or three species,It is few hundred species now the present of those hundred species along with genetic and environmental factor to diet that is going to decide the final outcome so it is almost impossible to reproduce those condition in gnotobiotic mice So negative result in such experiment consider difficult to interpret particularly when you took at the fact the human and mice are similar there are large difference on genetic and physiology different so for that we need to select a model or a animal model which is more closely associate with human one option is pig Gnotobiotic pigs they provide better physiology model suppose it is not as good as Human but may be better than mice.
FUNCTIONAL FOOD: Functional foods are foods that have potentially positive effect on health beyond basic nutrition. They promote optimal health and help reduce the risk of disease. These foods contain biologically active substances such as antioxidants Functional foods are generally separated into two categories: conventional and modified
Conventional foods are natural, whole-food ingredients that are rich in important nutrients like vitamins, minerals, antioxidants, and heart-healthy fats. Examples: Fruits, vegetables, nuts legumes etc. Modified foods have been fortified with additional ingredients, such as vitamins, minerals, probiotics, or fiber, to increase a food’s health benefits. Examples: fortified juices,fortified milk alternatives, such as almond, rice, coconut, and cashew milk etc.
Replacement Therapy: The basis of replacement therapy is the implantation and persistence within the normal microflora of relatively innocuous 'effector' bacteria that can competitively exclude or prevent the outgrowth of potentially disease- causing bacteria, without significantly disturbing the balance of the existing microbial ecosystem. It is also referred to as “bacteriotherapy” or “bacterial interference". they involve the use of live microbes for the prevention or treatment of an infectious disease same like probiotics but replacement therapy involves a dramatic and long-term change in the indigenous microbiota of a site, whereas this is not the case with probiotics always. it has a minimal immunological impact.
Bioactive natural products (BIONPs) -these are compounds mainly obtained from plants with a very wide range of biological activities like antimicrobial, anti-inflammatory, antioxidant, immunomodulatory, antidepressant, antihyperglycaemic (amylase activity), antihypertensive, anticarcinogenic, etc. These BIONPs are used as plant extracts or fractions. BIONPs compounds limitations-due to their low availability and stability, high volatility, and a great diffusion ability they are not recommended for implementation in the current medical practice. Bioactive compounds includes polyphenols, carotenoids, vitamins, omega-3 fatty acids, organic acids, and phytosterols.
Effector organisms/strains: In Replacement therapy , specific organism are used to prevent the colonisation of a site by a potentially pathogenic species or to displace such a species from the site, these are called as effector strain.
The effector strain used in replacement therapy is thought to cause a long-term change in the indigenous microbiota of a site , it can be naturally occurring or laboratory-derived effector strain.
It effects by following mechanisms like by blocking attachment sites, competing for essential nutrients, and producing inhibitory or cidal compounds, thus protects the host for as long as the it persists as a member of the indigenous microbiota.
The ideal characteristics of an effector organism is: It must not cause disease itself or otherwise predispose the host to other disease states by disrupting the ecosystem in which it resides. It should be active specifically against the target pathogen(s) Should be susceptible to low-risk antibiotics, such as penicillin, so that it can later be eliminated if necessary. Easy to grow and can be produced in a stable form for distribution. Easy to identify among the indigenous microbiota of the host It is necessary that it does not cause systemic toxicity or immunological sensitisation in the host. Capable of persisting in the host.
Example:An effector strain has been constructed for use in the replacement therapy of dental caries.By using Recombinant DNA methods, the Streptococcus mutans supercolonizing strain, JH1140, lactate dehydrogenase deficient by deleting virtually all of the ldh open reading frame (ORF)is made. And To compensate for the resulting metabolic imbalance, a supplemental alcohol dehydrogenase activity was introduced by substituting the adhB ORF from Zymomonas mobilis in place of the deleted ldh ORF. The resulting clone, was found to produce no detectable lactic acid during growth on a variety of carbon sources, and it produced significantly less total acid due to its increased production of ethanol and acetoin.
Functional foods are ingredients that offer health benefits that extend beyond their nutritional value. Some types contain supplements or other additional ingredients designed to improve health.
The concept originated in Japan in the 1980s when government agencies started approving foods with proven benefits in an effort to better the health of the general population (1Trusted Source).
Some examples include foods fortified with vitamins, minerals, probiotics, or fiber. Nutrient-rich ingredients like fruits, vegetables, nuts, seeds, and grains are often considered functional foods as well.
Functional foods are generally separated into two categories: conventional and modified.
Functional foods are foods that have a potentially positive effect on health beyond basic nutrition. Proponents of functional foods say they promote optimal health and help reduce the risk of disease.
A familiar example of a functional food is oatmeal because it contains soluble fiber that can help lower cholesterol levels.
Functional foods are foods that contain bioactive compounds naturally. Significantly, these foods can provide health benefits beyond the traditional nutritional value of the food.The traditional nutrients refer to the regular vitamins and minerals found in that particular food. Generally, traditional nutrients are essential to the diet, and their deficiency causes classical nutrient deficiency diseases. That means the functional foods contain a unique form of nutrient, which in turn promote the health.In other words, vitamin C in orange prevents scurvy. On the other hand, vitamin D in sardine can alleviate rickets. However, both vitamin C and vitamin D are essential nutrients. Therefore, neither orange nor sardine becomes a functional food. For instance, soy protein has a function in reducing cardiovascular disease. But since soy protein is not an essential nutrient in the diet, soy is a type of functional food. Likewise, red grapes containing phytochemical resveratrol, cranberry juice containing oligomeric proanthocyanidins, oat bran containing fiber, and barley containing beta-glucan are functional foods.
Functional foods are foods that have a potentially positive effect on health beyond basic nutrition. Proponents of functional foods say they promote optimal health and help reduce the risk of disease.
A familiar example of a functional food is oatmeal because it contains soluble fiber that can help lower cholesterol levels. They contain a type of fiber called beta glucan, which has been shown to reduce inflammation, enhance immune function, and improve heart health
Some foods are modified to have health benefits. An example is orange juice that's been fortified with calcium for bone health.
Functional food is a food claimed to have an additional function by adding new ingredients or more of existing ingredients. Idea was first described In the ancient Vedic texts from India, and in ChineseTraditional medicine. The vision to develop functional foods reflects the oriental philosophy that: ‘Medicine and food have a common origin’. Today, Japan is the only country that recognizes functional Foods as a distinct category, and the Japanese functional food Market is now one of the most advanced in the world. Known as foods for specified health use (FOSHU).
Categories of functional foods: Processed foods with added ingredients like Calcium-enriched fruit juice Basic food like Carrots (containing the anti-oxidant b-carotene) Processed foods like oat bran cereal. Isolated, purified preparations of active food ingredients like b-Glucan from oat bran. Food enhanced to have more of a functional component like Tomatoes with a higher levels of lycopene.
Neutraceuticals are the bioactive compounds found in fortified food, dietary supplements, and herbal products. However, they are often defined synonymously with functional foods due to the presence of a specific nutrient in a particular food. Some examples of nutraceuticals in fortified food are the calcium fortified in orange juice and vitamin D fortified in milk.
Nutraceuticals are products that are used for both nutrition and medicine. A substance that has physiological benefit or provides protection against chronic disease is referred to as a nutraceutical product. Nutraceuticals can be used to promote health, slow down the ageing process, prevent chronic diseases, extend life, and maintain the body's structure and function. Nutraceuticals have recently attracted a lot of attention due to its potential nutritional, safety, and therapeutic benefits.
What is meant by selective toxicity? The aim of antimicrobial therapy is to kill or inhibit the infecting organism without damaging the host; this is known as selective toxicity. This is commonly accomplished through the use of antimicrobial drugs. The aim of selective toxicity means that pharmaceutical companies developing antimicrobials have to identify structures or metabolic processes in the microorganism that is different to or absent from the host.
Selective toxicity against microbes means killing the microbial cells but not the host's cells.Antibiotics are antimicrobial agents which were originally defined as the substances produced by microorganisms that inhibit other microorganisms.Antimicrobial drugs are chemicals that are intended to have selective toxicity against microbes, meaning that they kill microbial cells but not the host's cells.Antimicrobial drugs include antibiotics, which were originally defined as substances produced by microorganisms that inhibit other microorganisms.
Selective toxicity is an important characteristic of an antimicrobial treatment, which means that it selectively kills or slows the growth of microbial targets while inflicting little or no harm to the host. In comparison to fungi, parasites, and viruses, most antimicrobial medicines now in clinical use are antibacterial. This is because the prokaryotic cell affords a broader diversity of distinct targets for selective toxicity. Each antibacterial medication class has its own mechanism of action (the way in which a drug affects microbes at the cellular level).
What are Riboswitches? 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. The typical riboswitch contains two distinct functional domains. 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 discriminate between chemically related metabolites with high selectivity to elicit the appropriate regulatory response. A second domain, the expression platform, contains a secondary structural switch that 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.
The function of riboswitches is tied to the ability of RNA to form a diversity of structures. The most basic of these is the double-stranded helix, similar to that found in DNA. Riboswitches are composed of two domains: the aptamer domain and the expression platform.Riboswitches are organized into families and classes according to two features: the type of ligand they bind, and their secondary structure.
The term riboswitch was used to define RNAs that control gene expression by binding metabolites without the need for protein factors or a protein-independent gene regulation mechanism. Riboswitches form highly specific binding pockets for the target metabolite and undergo allosteric changes in structure. Transcription termination in bacteria is a classical example of riboswitch in action. The most widespread riboswitch class discovered to date responds to the coenzyme thiamin pyrophosphate (TPP) this riboswitch is quite common in plants and fungi. Common ligands that are sensed by riboswitches; includes magnesium ions, nucleic acid precursors, enzyme cofactors, and amino acid residues. 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.
Riboswitches are small molecule ligand-binding elements present in the 5′-untranslated region (UTR) of mRNAs that exert regulatory control over the transcript in a cis-fashion. A typical riboswitch is made up of two functional domains. An aptamer domain recognises the effector molecule and folds into a compact three-dimensional fold to scaffold the ligand binding pocket. To elicit the right regulatory response, these RNA receptors, like proteins, must discriminate between chemically similar compounds with high selectivity.A secondary structural switch interfaces with the transcriptional or translational machinery in a second domain, the expression platform. The switching sequence, an area of overlap between these two domains that controls 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, is responsible for regulation.
A riboswitch is a cis-regulatory RNA element that regulates downstream or upstream gene expression in response to a specific ligand molecule. The ability of RNA to create a variety of forms is linked to riboswitches' activity. The 5' untranslated region (5' UTR; a segment of RNA preceding the translation start site) of bacterial mRNA is where riboswitches are most frequently found. They control the occlusion of transcription repression or translation start signals. The thiamine pyrophosphate (TPP) riboswitch affects splicing at the 3' end of certain eukaryotic mRNA. Inhibitors of riboswitches have a low efficacy rate.
Riboswitches are structural RNA elements found in the 5' untranslated regions of certain mRNAs that control gene expression by terminating transcription prematurely or suppressing translation initiation. The functional domains of a typical riboswitch are two. An aptamer domain detects the effector chemical. The expression platform, a second domain, communicates with the transcriptional and translational machinery. The switching sequence, which spans these two domains and drives RNA folding into one of two mutually incompatible configurations in the expression platform that represent the on and off states of the mrna, is responsible for regulation.
Riboswitches : it is a common RNA regulatory element .Riboswitches are structured noncoding RNA domains that selectively bind metabolites and control gene expression . Riboswitches, RNA elements found in the untranslated region, regulate gene expression by binding to target metaboloites with exquisite specificity.
ANTIGENIC DRIFT: mutations which produce small changes in antigenic drift and these occur in same strain. The variation in the antigenic pool is by accumulation of gene mutations. The change is gradual. Result in new viral strain. Occurs frequently. Easy to treat it. Example, occurs in influenza virus A,B and C, HIV. May infect animals of the same species. Usually responsible for epidemics in between pandemics.
ANTIGENIC SHIFT: Mutations which result in a major change and produce new strains are referred to as antigenic shift. Two different strains of viruses combine to form a new subtype. The change is sudden and drastic. Result in a new subtype of the virus. Occurs once in time. Difficult to treat. Example: occurs in influenza virus A. Give rise to pandemics, which occurs irregularly and unpredictably.
1) Antigenic Shift : Antigenic shift refers to the gene recombination occurring when influenza viruses re-assort. It is major Antigenic Change. Large change in nucleotides of RNA. It results from Genome re-assortment between different subtypes. It occurs only in Influenza Virus A. 2) Antigenic drift : Mutations causing minute changes in the hemagglutinin and neuraminidase antigens on the surface of the Influenza virus is termed antigenic drift. It results due to accumulation of point mutations in the gene. Small mutation of RNA. It occurs in Influenza Virus A, B and C.
Antigenic drift involves the accumulation of a series of minor genetic mutations. Antigenic shift involves “mixing” of genes from influenza viruses from different species.
The main difference between antigenic drift and antigenic shift is that antigenic drift is a mechanism for variation in viruses by accumulating mutations within genes, which code for antigen-binding sites whereas antigenic shift is a process of combining two types of viruses to form a new subtype with a mixture of surface antigens of the original viruses.
Antigenic drift is the result of a sequence of small genetic changes accumulating over time. Antigenic shift occurs when genes from various influenza viruses are mixed
Antigenic drift: As the influenza virus reproduces, its genes change slightly. Over time, these small changes accumulate, so that your immune system becomes less effective at protecting you from the virus. Antibodies now have trouble recognizing the changed virus. This is called antigenic drift.
Antigenic Shift: Both human and bird influenza viruses can attach to and enter the lung cells of a pig. During replication, both versions of influenza virus release their genetic material into the pig cell. Then, the genes from the different viruses can “mix” creating new versions of influenza virus. Because the genes in the resulting virus are dramatically different, this is called antigenic shift.
Antigenic shift can produce a version of influenza virus that no person’s immune system has antibodies to protect against. This is when an influenza pandemic can occur.
Antigenic drift is a minor antigenic change resulting in a new strain of virus while the antigenic shift is a major antigenic change, resulting in a new subtype.
Two glycoproteins on the surface of influenza virus, hemagglutinin and neuraminidase, play a role in the process of influenza virus infection and release.
Hemagglutinin (HA) of the trimer and neuraminidase (NA) of the tetramer are two glycoproteins on the IAV surface. They play an important role in the process of virus infection and escape, each with high variability owing to adaption to environmental changes and host immune escape response.
Haemaglutinin (HA) and Neuraminidase (NA) two well-known glycoproteins found on the surface of the Influenza A virus are important molecules for viral infection that bind to Sialic acid.
The influenza virus major surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA) dominate the virion surface and form the main targets for these neutralizing antibodies. In addition to the mutations that arise due to antigenic drift, the HA and NA of influenza A viruses (IAVs) can exist in different forms.
Influenza virus neuraminidase cleaves sialic acid groups from cell glycoproteins, enabling release of the virus from host cells. Neuraminidase also contributes to virus binding to the sialic acid groups of cell glycoproteins, which could complement the receptor-binding function of hemagglutinin, enhancing enzymatic activities of neuraminidase, and facilitate virus infection.
Neuraminidase(NA) activity in the IAV infection cycle has primarily been limited to assisting virion progeny egress from infected cells. NA interacts with sialic acid, a terminal structure linked to underlying sugar residues expressed at the cell surface by glycoproteins or glycolipids. In the last stages of infection, NA plays a critical role. Viral NA removes sialic acids from cellular receptors as well as newly generated NA on nascent virions that have been sialylated as part of the host cells glycosylation processes. Virion aggregation is prevented by NA cleavage of sialic acids which also hinders virus attachment to the dying host cell.
Drugs called neuraminidase inhibitors, which include oseltamivir (Tamiflu) and zanamivir (Relenza), inhibit the release of influenza A and B viruses from host cells. This inhibition stops the process of viral replication. Neuraminidase inhibitors are commonly used in both the prevention and the treatment of influenza.Influenza and its interactions The interaction of viral glycoproteins with cell surface receptors is a key factor in infectivity and thus transmissibility. Understanding these connections is crucial for determining which criteria are required to predict pandemic risk. Influenza The hemagglutinin (HA) glycoprotein is responsible for virus attachment to cell surface sialic acid receptors, while the neuraminidase (NA) glycoprotein is responsible for cleaving the receptor to allow virus release. Previous research has shown that NA proteins of the N9 subtype can bind sialic acid through a different binding site from the active site of sialidase.
An important function of the NA protein is to remove sialic acid from glycoproteins. Sialic acid is present on many cell surface proteins as well as on the viral glycoproteins; it is the cell receptor to which influenza virus attaches via the HA protein. The sialic acids on the HA and NA are removed as the proteins move to the cell surface through the secretory pathway. Newly released virus particles can still potentially aggregate by binding of an HA to sialic acid present on the cell surface. Years ago Peter Palese showed that influenza virus forms aggregates at the cell surface when the viral neuraminidase is inactivated. The NA is therefore an enzyme that is essential for release of progeny virus particles from the surface of an infected cell.
Martinus Beijerinck is the Father of Virology. He was a Dutch microbiologist who was the first person to use the term "virus". He originated selective culture techniques, also known as enrichment culturing, and was the first to isolate a wide range of microorganisms.
Martinus Beijerinck is often called the Father of Virology.
In 1892, Dmitri Ivanovsky used one of these filters to show that sap from a diseased tobacco plant remained infectious to healthy tobacco plants despite having been filtered.
Martinus Beijerinck called the filtered, infectious substance a ‘virus’ and this discovery is considered to be the beginning of virology.
What do you mean by Malaria paroxysm ? As the disease progresses, some patients may develop the classic malaria paroxysm with bouts of illness alternating with symptom-free periods. The malaria paroxysm comprises three successive stages. The first is a 15-to-60 minute cold stage characterized by shivering and a feeling of cold. Next comes the 2-to-6 hour hot stage, in which there is fever, sometimes reaching 41°C, flushed, dry skin, and often headache, nausea, and vomiting. Finally, there is the 2-to-4 hour sweating stage during which the fever drops rapidly and the patient sweats.
Malaria paroxysms are antiparasite responses in Plasmodium vivax malaria that while painful to the human host, almost never result in serious acute pathology.The malaria paroxysm is divided into three stages. Shivering and a sensation of cold characterise the initial stage, which lasts 15 to 60 minutes. The next stage is the 2-to-6-hour hot stage, which includes a fever (up to 41°C), flushed, dry skin, headache, nausea, and vomiting.
Some patients may acquire the characteristic malaria paroxysm as the disease progresses, with periods of illness interspersed with symptom-free periods. The three stages of the malaria paroxysm are as follows: The first stage is a 15-to-60-minute chilly period marked by shivering and a cold sensation. Then there's the 2-to-6-hour hot stage, which includes a fever (up to 41°C), flushed, dry skin, headache, nausea, and vomiting. Finally, there occurs the 2-to-4-hour sweating stage, during which the patient's fever rapidly decreases and he or she sweats profusely.
Paroxysm is an acute fever that is typically preceded by chills and rigor. It occurs during various types of microbial infection, malaria being one of them. The malaria paroxysm comprises three successive stages. The first is a 15-to-60 minute cold stage characterized by shivering and a feeling of cold. Next comes the 2-to-6 hour hot stage, in which there is fever, sometimes reaching 41°C, flushed, dry skin, and often headache, nausea, and vomiting. Finally, there is the 2-to-4 hour sweating stage during which the fever drops rapidly and the patient sweats.
Ques- What is the difference between probiotics and prebiotics?
Ans: Probiotics are 'living' friendly bacteria that are comparable to those that live in our intestines. They can be found naturally in cultured or fermented foods including yoghurt, buttermilk, aged cheese, sauerkraut, sourdough bread, miso, tempeh, and kombucha, a type of fermented tea, as well as taken as a supplement. Probiotics aid in the maintenance of healthy quantities of good bacteria in the intestines, strengthen our immune systems, are beneficial to anyone suffering from bloating, gas, or flatulence, and may help shorten the duration of diarrhoea in children.They may also aid in the recovery of beneficial bacteria following antibiotic treatment. Probiotics come in a variety of forms, each with its own set of characteristics. Lactobacillus acidophilus and bifidibacterium lactis, which are commonly found in yoghurt, may be familiar to you.
Prebiotics are 'nonliving' food elements that bypass digestion and reach the large intestine, where they 'feed' the good bacteria in our gut, allowing them to grow and thrive. Many foods naturally contain prebiotics such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS), such as: Legumes,Products made from whole wheat, Foods made with rye, Artichokes/Onions, Cabbage,Garlic,Chicory is a type of root vegetable.
Q.Describe the term Dysbiosis? Ans.Dysbiosis is a term used to describe a "imbalance" in the gut microbiota that is linked to disease. This imbalance could be caused by changes in the relative abundance of microorganisms or by the addition or removal of community members. Dysbiosis is a misalignment of commensal flora with respect to the individual organism's endobiogenic demands. This imbalance could be caused by one of three factors: (1) a lack of commensal flora (2) a reduction of variety in the normal commensal flora & (3) pathogenic flora competing with the commensal microbiome. Exposure to different environmental factors, including as nutrition, chemicals, medicines, and viruses, can cause changes in the microbiota. Dysbiosis of the gut microbiota is increasingly being linked to the aetiology of both intestinal and extraintestinal illnesses. Irritable bowel syndrome (IBS), celiac disease, and inflammatory bowel disease are examples of intestinal illnesses, while allergies, asthma, metabolic syndrome, cardiovascular disease, and obesity are examples of extra-intestinal disorders.
Dysbiosis is a condition in which the gut bacteria become imbalanced.
Factor for dysbiosis: excessive or wrong use of antibiotics, excessive alcohol consumption, increased intake of sugar or protein,chronic stress. poor dental hygiene and anxiety.
Development of resistance is advantageous to pathogen or not? Pathogen develops resistance against drug so that it can survive there for long time so in this context resistant development seems to be advantageous, While to gain resistance bacteria need to invest energy ( add genes ), May expriance genetic burden also so in this aspect it dose not seems to be advantageous, and that's why antivirulence agents are emerging strategies as they provide an option of survival without this energy investment.
Whether signal supply inhibitor or signal response inhibitors are of benefit to us?
Signal supply inhibitors can't stop 100% production of signal, while signal response inhibitors won't stop production but makes production useless as they will compromise the cell's ability to respond to signal and so most of the cells will behave as signal blind, If cell's won't have signal response ability they can't participate in quorum sensing which is not true in case of signal supply inhibitors,( if cell's don't have ability for signal production still can participate in quorum sensing) , so may be signal response inhibitors are good strategy to use.
It's a natural physiological reaction. When your brain raises its internal thermostat to combat an infection, the rest of your body works overtime to generate extra heat to keep up with the higher temperature.
It’s actually a normal physiological response. As soon as your brain shifts its internal thermostat to a higher set point to fight off an infection, the rest of your body goes to work trying to generate extra heat to meet that higher temperature goal. Suddenly, you’re technically below your new “ideal” core temperature, so you feel cold.
Which pathogenicity strategyy is smarter, acute or chronic?
Acute infection strategy is smarter than chronic. In chronic infection the infectious agent stay in host for long time and in acute infection infectious agent kills the host (the source of nutrition) In acute infection bacteria grows much faster compared to chronic infection, replicate more faster, successful transmission.
Do all pathogens have PAI ?if not, Is there any advantage of not having PAI?
It is not necessary that all pathogens have PAI, some may have lost it, this may be due to it's habitat, (diversity) Genome reduction helps it to become more specific to particular organ. Example: H. Pylori have lost some genes so it's genetic burden is less so it will become specific for that host.
Amphotericin B (Amb) is one of the oldest known effective antifungal agents the current guideline for the treatment for mucormycosis they recommend use of antifungal treatment along with surgical debridement direction of correction of risk factor (correction of risk factor means the person is suffering from high sugar then while treating him for mucormycosis the initial also try to to control the sugar) Surgical debridement refers to removal of the part of tissue which is infected by the mucor but surgical debridement has quite effective an extensive repeated surgical processes may be recommended to achieve local control and improve outcome and that can be heavy on the patient. Surgery may be an option for such certain body sides crucial but the infection in the nasal cavity or in the eyes or in the nervous system then the surgery remains the compulsory option in the case of post mucormycosis surgery is mandatory.
Amphotericin B along with Liquid formulation, Liquid formulation of Amphotericin B considered to be superior and another antibiotic known as Posaconazole are the only antifungal drug available in vitro and in vivo activity against mucorales. Posaconazole have at least three antibiotics known to be capable working against mucor.
How does a microbe like P. Aeruginosa make a decision regarding causing acute versus chronic disease?
Bacteria either initiate an acute infection via variables such as TTSS and different toxins, or build a chronic, biofilm-like infection in response to unidentified signals.The infection's point of entrance may influence whether it becomes acute or chronic.When developing in the CF lung,P.aeruginosa appears to be growing in a biofilm-like fashion.This growth approach may be the result of specific environmental signals and/or host factors found in the lungs of patients with this condition.Other factors,such as the host's immunological status,tissue integrity, and patient nutrition,could influence whether microorganisms start an acute or chronic infection.
It is one of the most recent problems reported by widely reported widely with coronavirus infection, the considerable number of coronavirus patient stay becomes susceptible to the fungi called mucor in fact it is not the single fungus group which is known as mucorales group which includes rizosphere as well as mucus fungi has not primary involved to the pathogens they have evolved to leave the saprophytic life for free human life so fungi has not been major cause of mortality and morbidity till the recent news but now we are having some member in the human population who are organ transplantation for condition like HIV infection making them immunocompromised and in those cases even the pathogens who are not mainstream profession pathogens they can also cause the infection what we called as secondary infection of opportunities for a pathogen so earlier se to the lesser incidence of fungal infection not much attention was paid to discovery of antifungal agents even today we have very small number of antifungal agents available in general for example some of the azoles or amphoteric compounds we have general it is difficult to the antibiotic against fungi because funge are eukaryote and human host are also eukaryote so if target something in fungi is high probability that the antifungal agent target the same thing in humans for example if we stop.Protein synthesis inhibiting ribosome.Ribosomes are ATS fungi as well as human so the criteria of selective toxicity very difficult to achieve only certain things chitin cell wall they can be targeted from they are absent from human system you know you human cell like any other animal cell do not contain cell wall that so that you can target that they have a cell wall but they do share the machinery like mitochondria ribosome cell membrane so it does difficult and most of the antifungal are most toxic are the side effects of of the antifungal treatment are sometimes it use effectively and initially and when we say it is not sufficient to you hospital facility suffering from primary infection to die and the number of living immunocompromised people must be less since we have more advanced facilities in last 10-20 years the number of immunocompromised people in the living condition for example those living after normal organ transplantation and also after having AIDS they still continue the life that means overall se the life expectancy has increased for example in India was below 50 at the time of independence now it is around 67 that means the more number of elderly people more number of immunocompromised people who are are already having compromised system or or infected by some infection so fungi make them easy target so the probability of the secondary infection by the opportunistic infection has increased the strange rise by the side effect of of advance medical sciences and facilities.
1) Probiotics = probiotics are live microbial feed supplements which beneficially affect the host by improving microbial balance.
ReplyDelete2) prebiotices = A
selectively fermented ingredient that results in specific changes in the composition of the gastrointestinal microbiota, thus conferring benefits upon host health.
3) Postbiotices = Postbiotices are non viable bacterial or metabolic products from microorganisms that have biological activity in the host, probiotics feed on prebiotics, postbiotics are produced.
4) Synobiotics = Synobiotics are defined as synergistic mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and colonization of live benefical microorganism in the gastrointestinal tract of the host.
what is gut brain axis?
ReplyDeleteThe gut-brain axis (GBA) is a bidirectional link between the central nervous system (CNS) and the enteric nervous system (ENS) of the body. It involves direct and indirect pathways between cognitive and emotional centres in the brain with peripheral intestinal functions.
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DeleteThe communication between the CNS and the intestine, and it happens through microbiota so it is called Gut-Brain Axis.
Deletegerm-free mice treated with antibiotics for reduce the microbial diversity within the intestine, showed that several neurological problems occur in mice with reduced proper gut microbiota.
microbes can produce neuroactive molecules that directly contribute to the communication between the gut and the brain.
Example : Neurotransmitters, like acetylcholine, and serotonin, produced by bacteria belonging to Lactobacillus, Bifidobacteria, Enterococcus, and Streptococcus species, it can influence brain cell physiology.
Another example microbial metabolite that influences microglia activity is tryptophan, The importance of tryptophan metabolism in maintaining CNS homeostasis. Hemostasis is the mechanism that leads to cessation of bleeding from a blood vessel.
Reference doi :10.3389/fimmu.2020.604179
The gut–brain axis is a bidirectional communication system between the central nervous system (CNS) and the GI tract. Regulation of the microbiota–brain–gut axis is essential for maintaining homeostasis, including that of the CNS. A number of approaches have been used to probe this axis, including the use of germ-free animals, probiotic agents, antibiotics, or animals exposed to pathogenic bacterial infections.
DeleteThe communication between the CNS and the intestine, and it happens through microbiota so it is called Gut-Brain Axis.
Deletegerm-free mice treated with antibiotics for reduce the microbial diversity within the intestine, showed that several neurological problems occur in mice with reduced proper gut microbiota.
microbes can produce neuroactive molecules that directly contribute to the communication between the gut and the brain.
The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions.
Delete1.Primary colonization: Microorganisms comes and sitting on the surface of body it's called primary colonization.
ReplyDelete2.secondary colonization:when that organisms adapte that conditions and establishes their colony on the surface it's called secondary colonization.
3.Neutraceuticals: It's products, which other than nutrition are also used as medicine. A nutraceutical product may be defined as a substance, which has physiological benefit or provides protection against chronic disease.
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ReplyDeleteSuccession-after the secondary colonization, the established colony evolves over time by some structural changes,
ReplyDeleteClimax community-it is the final stage of succession where the community is largely stable.
And Resiliance-it is the capacity to recover any function of interest after it has been completely or partially lost due to any kind of disturbance, (like some catastrophic events)
These are the stages how microbio e changes.
1.) Microbiome refers to microbes host elements such as epithelium, immune components and their products.The human microbiome comprises bacteria, archaea, viruses and eukaryotes which resides within and outside our bodies These organisms impact human physiology both in health and in disease, contributing to enhancement or impairment of immune functions.
ReplyDelete2.) Gut Dysbiosis is defined as an imbalance in the gut microbial community that is associated with disease. Some effects of dysbiosis, such as stomach upset, are temporary and mild. In many cases, your body can correct the imbalance without treatment.
3.) Gut–brain axis is the relationship between the GI tract and brain function and development and broadly it is defined, the gut–brain axis includes the central nervous system, neuroendocrine and neuroimmune systems, including the hypothalamic–pituitary–adrenal axis (HPA axis), sympathetic and parasympathetic arms of the autonomic nervous system, including the enteric nervous system and the vagus nerve, and the gut microbiota. The first of the brain–gut interactions shown, was the cephalic phase of digestion, in the release of gastric and pancreatic secretions in response to sensory signals, such as the smell and sight of food. This was first demonstrated by Pavlov. Interest in the field was sparked by a 2004 study showing that germ-free (GF) mice showed an exaggerated HPA axis response to stress compared to non-GF laboratory mice. As of October 2016, most of the work done on the role of gut flora in the gut–brain axis had been conducted in animals, or on characterizing the various neuroactive compounds that gut flora can produce.And the studies with humans is measuring variations in gut flora between people with various psychiatric and neurological conditions or when stressed, or measuring effects of various probiotics (dubbed "psychobiotics" in this context) – had generally been small and were just beginning to be generalized. Whether changes to gut flora are a result of disease, a cause of disease, or both in any number of possible feedback loops in the gut–brain axis, remained unclear.
4.) Colonization resistance was first identified in 1967, and it was initially referred to as antibiotic associated susceptibility. It was observed that animals being treated with the antibiotic streptomycin were susceptible to Salmonella enterica at doses 10,000 fold lower than the standard minimal infectious dose.
4.) Probiotics are beneficial bacteria found in certain foods or supplements.
5.) Prebiotics are like the food, probiotics are the microorganisms themselves, and postbiotics are the results of probiotics consuming that food.
6.) Postbiotics are byproducts of the fermentation process carried out by probiotics in the intestine. In other words as probiotics feed on prebiotics, postibiotics are produced Although we normally thing of waste as bad probiotics are responsible for multiple important health- boosting functions in our gut.
ReplyDelete7.) Synbiotics are mixtures of probiotics helpful gut bacteria and prebiotics non-digestible fibers that help these bacteria grow. Specifically, they're combinations of these two things that work together (synergistically) in your digestive tract.
8.) Climax community is one that has reached the stable stage. When extensive and well defined, the climax community is called a biome examples are tundra, grassland, desert, coniferous, and tropical rain forests.
9.) Communicable disease means an illness caused by an infectious agent or its toxins that occurs through the direct or indirect transmission of the infectious agent or its products from an infected individual or via an animal, vector or the inanimate environment to a susceptible animal or human host,Some examples of the communicable disease include HIV, hepatitis A, B etc.
10.) Non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another,Some examples of the NCDs include Parkinson's disease, autoimmune diseases, strokes, heart diseases, cancers, diabetes, chronic kidney diseases, Alzheimer's disease are collectively responsible for almost 70% of all deaths worldwide.
Which two major phyla of bacteria found in the human intestine ??
ReplyDeleteThe major bacterial phyla found in the human gut are Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria.
DeleteFirmicutes and Bacteroidetes are the two major bacterial phyla present in the gut.
DeleteBacterial phyla that reduce or regulate intestinal inflammation, such as Bacteroidetes (e.g., Bacteroides fragilis), Firmicutes (e.g., Lactobacillus, F. prausnitzii and Clostridium strains), and Actinobacteria (e.g., Bifidobacterium), are reduced in IBD.
DeleteReference: https://doi.org/10.1016/B978-0-12-384931-1.00004-0
Proteobacteria,Verrucomicrobia,Firmicutes are the major bacterial phyla found in human gut.
DeleteFirmicutes and Bacteroidetes are the two major bacterial phyla present in the human gut intestine.
DeleteFirmicutes and Bacteroidetes are two major phyla of bacteria found in the human intestine.
DeleteTissue tropism : It is the range of tissues which can support the growth of a particular microorganism (commonly bacteria and viruses). Some microbes have a broad tissue tropism and can infect many types of cells and tissues while other may infect primarily a single tissue.
ReplyDeletePsychobiotics : are beneficial bacteria (probiotics) or support for such bacteria (prebiotics) that influence bacteria–brain relationships. Psychobiotics exert anxiolytic and antidepressant effects characterised by changes in emotional, cognitive, systemic, and neural indices. Bacteria–brain communication channels through which psychobiotics exert effects include the enteric nervous system and the immune system.
Law of Minimum : Given by Liebig, states 1 that growth is controlled not by the total of resources available, but by the scarcest resource (limiting factor).
Law of Tolerance : Given by Shelford, states that the abundance or distribution of an organism can be controlled by certain factors (e.g. the climatic, topographic, and biological requirements of plants and animals) where levels of these exceed the maximum or minimum limits of tolerance of that organism.
What are Nutraceuticals ?
ReplyDeleteNutraceuticals are products, which other than nutrition are also used as medicine. A nutraceutical product may be defined as a substance, which has physiological benefit or provides protection against chronic disease. Nutraceuticals may be used to improve health, delay the aging process, prevent chronic diseases, increase life expectancy, or support the structure or function of the body. Nowadays, nutraceuticals have received considerable interest due to potential nutritional, safety and therapeutic effects.
Nutraceutical” is a substance that may be considered a food or part of a food which provides medical or health benefits, encompassing prevention and treatment of disease. Products as diverse as isolated nutrients, dietary supplements and diets to genetically engineered “designer” foods, herbal products, and processed foods (cereals, soups, beverages) may be included under the umbrella of nutraceuticals. In India, nutraceuticals have been defined under Clause 22 of the Food Safety and Standards Act (FSSA), 2006. This chapter describes the role of nutraceuticals in health and how they are different from functional foods and dietary supplements.
DeleteReference: https://doi.org/10.1016/B978-0-12-801773-9.00040-6
Nutraceutical” is a substance that may be considered a food or part of a food which provides medical or health benefits.
DeleteNutraceuticals are used to improve health, delay the aging process, prevent chronic diseases, increase life expectancy, or support the structure or function of the body.
Nutraceutical products can be considered non-specific biological therapies used to promote general well-being, control symptoms, and prevent malignant processes.
DeleteThe term “nutraceutical” combines the two words of “nutrient,” which is a nourishing food component, and “pharmaceutical,” which is a medical drug.
The definition of nutraceuticals and their related products generally depends on the source. These products can be classified on the basis of their natural sources, pharmacological conditions, as well as chemical constitution of the products. Most often, nutraceuticals are grouped into four categories that include dietary supplements, functional food, medicinal food, and farmaceuticals.
DeleteNutraceuticals are the pharmaceutically blended products that possess both nutritional as well as the medicinal value.
They are used in the prevention and treatment of mental health issues and disorders.
Benefits:
Improve Eye Health.
Improve Gut Health.
Treat Inflammation.
Improve Immune Function.
Improve sleep.
Nutraceulical can give allergic reactions caused by interactions with other nutraceuticals or therapeutic drugs.
Types:
Traditional Nutraceuticals:
Chemical constituents,
Probiotic microorganisms,
Nutraceutical enzymes.
Nontraditional Nutraceuticals:
Recombinant Nutraceuticals,
Fortified Nutraceuticals.
Reference:
https://doi.org/10.1155/2019/6908716
What are the emulsifiers/food emulsifiers/dietary emulsifiers ? How they affect human gut microbiota ?
ReplyDeleteEmulsifiers are a class of food additives used in food processing to alter the flavor, improve the texture, stability, and shelf-life of foods. Structurally, emulsifiers contain both hydrophobic and hydrophilic moieties that allow them to exist in both water and lipid fractions, thereby creating a consistent, homogenous mixture of immiscible liquids. Without emulsifiers, food products such as salad dressings, chocolate bars, mayonnaise, yogurt, and ice cream would not exist.
Examples of commonly used emulsifiers include CMC, P80, arabinogalactan, carrageenan, and gum arabic.
Emerging evidence suggests that permitted dietary emulsifiers may impact on gut health through impairing intestinal barrier function, thus increasing antigen exposure, and/or by modulating the microbiota, thus potentially increasing the incidence of inflammatory bowel disease (IBD) and metabolic syndrome.
Emulsifier, in foods, any of numerous chemical additives that encourage the suspension of one liquid in another, as in the mixture of oil and water in margarine, shortening, ice cream, and salad dressing. A number of emulsifiers are derived from algae, among them algin, carrageenan, and agar. Lecithins, such as those found in egg yolk, are also used as emulsifying agents.
DeleteThe use of additives in food products has become an important public health concern. In recent reports, dietary emulsifiers have been shown to affect the gut microbiota, contributing to a pro-inflammatory phenotype and metabolic syndrome.
A food emulsifier, also called an emulgent, is a surface-active agent that acts as a border between two immiscible liquids such as oil and water, allowing them to be blended into stable emulsions. Emulsifiers also reduce stickiness, control crystallization and prevent separation.
DeleteEmerging evidence suggests that permitted dietary emulsifiers may impact on gut health through impairing intestinal barrier function, thus increasing antigen exposure, and/or by modulating the microbiota, thus potentially increasing the incidence of inflammatory bowel disease (IBD) and metabolic syndrome.
Terms of Tissue tropism, Law of tolerance, Law of medium has nothing do specific with human microbiome they are applicable in general to wild ecological concepts including human microbiome ecosystem.
ReplyDeleteTissue tropism indicates the certain species they will always found associate with certain tissues like Staphylococcus will associate with nasal cavity so the specific organism present at specific organ or in other words a given tissue support colonization has certain types of organization only this is known as tissue tropisum. Now this tissue tropisum is a result of the two situation which can explain by two laws first is law of tolerance and second law of minimum.
Law of Tolerance suggest that at any particular site only those organism survive who can tolerate the physochemical situation existing at that body site Eg:- Stomach has ph acidic food so only those orgamism can survive who can tolerate this they could survive there similarly with large intestine it is obligate anaerobic condition so only the organisms who can tolerate absence of oxygen they can survive there.
Law of Minimum tells any site which can provide the nutritional requirements of the organism of the particular type only those organism can find there.
What is functional redundancy?
ReplyDeleteFunctional redundancy in soil microbial communities seems to contradict the notion that individual species have distinct metabolic niches in multi-species communities. All soil microbiota have the metabolic capacity for “basic” functions, but only a few soil microbiota participate in “rare” functions. The objective of this perspective paper is to use the phylogenetic niche conservatism theory as an explanation for the functional redundancy of soil microbiota.
DeleteReference: https://doi.org/10.1016/S1002-0160(19)60826-X
Although the taxonomic composition of the human microbiome varies tremendously across individuals, its gene composition or functional capacity is highly conserved — implying an ecological property known as functional redundancy. The human microbiome harbors a plethora of taxa carrying distinct genes and gene families1, making it functionally diverse. At the same time however, the human microbiome is functionally redundant, with many phylogenetically unrelated taxa carrying similar genes and performing similar functions. For example, dietary carbohydrates can be metabolized by either Prevotella (from the phylum Bacteroidetes) or Ruminococcus (from the phylum Firmicutes).
DeleteA characteristic of species within an ecosystem where certain species contribute in equivalent ways to an ecosystem function such that one species may substitute for another.
DeleteThe human microbiome's taxonomic composition varies greatly between individuals, but its gene composition or functional capability is highly preserved, implying functional redundancy as an ecological feature. The origin of functional redundancy, which is thought to underpin the human microbiome's stability and resilience, has yet to be discovered.
DeleteWhat are psychobiotics?
ReplyDeletePsychobiotics interacts with gut microbial community and it alters the microbiome in such a way that release the happy hormones..In other word it helps to fight with anxiety,mood disorder, depression, etc.
DeletePsychobiotics are a group of probiotics that affect the central nervous system (CNS) related functions and behaviors mediated by the gut-brain-axis (GBA) via immune, humoral, neural, and metabolic pathways to improve not only the gastrointestinal (GI) function but also the antidepressant and anxiolytic capacity. As a novel class of probiotics, the application of psychobiotics has led researchers to focus on a new area in neuroscience. In the past five years, some psychobiotics strains were reported to inhibit inflammation and decreased cortisol levels, resulting in an amelioration of the symptoms of anxiety and depression. Psychobiotics are efficacious in improving neurodegenerative and neurodevelopmental disorders, including autism spectrum disorder (ASD), Parkinson's disease (PD) and Alzheimer's disease (AD). Use of psychobiotics can improve GI function, ASD symptoms, motor functions of patients with PD and cognition in patients with AD. However, the evidence for the effects of psychobiotics on mental and neurological conditions/disorders remains limited. Further studies of psychobiotics are needed in order to determine into their effectiveness and mechanism as treatments for various psychiatric disorders in the future.
DeleteReference : https://doi.org/10.1016/j.jfda.2019.01.002
psychobiotics is gut microbes which shows promise in treating mental health problems such as depression and anxiety.
Deletethese bacteria are capable of producing and delivering neuroactive substances such as gamma-aminobutyric acid and serotonin, which act on the brain-gut.
Lactobacillus helveticus and Bifidobacterium longum have both been found to be good probiotics for brain health, and for anxiety.
Refrance : https://doi.org/10.1038/s41398-021-01422-7
Psychobiotics were previously defined as live bacteria (probiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria.
DeleteWhat is HPA axis?? What is role of HPA axis
ReplyDeleteThe HPA axis is a term used to represent the interaction between the hypothalamus, pituitary gland, and adrenal glands, it plays an important role in the stress response.
DeleteThe hypothalamic–pituitary–adrenal (HPA) axis is considered to be the major neuroendocrine system regulating various body processes in response to psychological stressors and physical stressors, including infections, ensuring an adequate response to the stressor. Emerging evidence points to a bidirectional communication between the neuroendocrine system and gut microbiota.
DeleteThe main function generally attributed to the HPA axis involves the body's reaction to stress. When something stressful happens to us, our initial response is mediated by the sympathetic nervous system. This response occurs almost immediately, and results in the secretion of epinephrine and norepinephrine, both of which work to enact changes that you would generally expect if you felt stressed and/or frightened, like increased heart rate and perspiration.
DeleteThe hypothalamic pituitary adrenal (HPA)axis is central stress response system. The HPA axis is intertwining of the central nervous system and endocrine system. The HPA axis is responsible for the neuroendocrine adaptation component of the stress response
ReplyDeleteWhat are enterotypes?
ReplyDeleteEnterotypes are clusters of bacterial communities in the gut that allow researchers to identify common traits that bring people together. They are associated with specific long-term eating patterns.
Enterotypes are stable clusters of bacterial communities that co-exist together. These clusters do not have strict borders. Rather, they are fluid and distinguished by a dominant bacterial community within the person’s microbiome.
DeleteA classification of living organisms based on the bacteriological composition of their gut microbiota is known as an enterotype. Peer Bork and his colleagues revealed the discovery of three human enterotypes in the April 2011 issue of Nature. They discovered that age, gender, body weight, or country divides have no bearing on enterotypes. There is evidence that long-term diet has an impact on enterotype.
DeleteEnterotypes are shaped in large part by the particular long-term dietary habits of every individual for example, protein and fat-rich diets favor the proliferation of bacteria of the Bacteroides genus.
DeleteQ When a pathogenic E.coli enters our body our immune system most of the time it produces antibodies but when the same E.coli is present in the GI tract as a part of our normal human microbiome then our body is unable to recognize it why?
ReplyDeleteAns- TLRs recognize microbes by binding to pathogen-associated molecular patterns. Toll-like receptors are components of the innate immune system that respond to exogenous infectious ligands (PAMPs) and endogenous molecules that are released during host tissue injury/death (damage-associated molecular patterns, DAMPs). Our immune system does not respond to the pathogenic E.coli in our GI tract as the microbe is currently not harming or damaging any tissues or not causing any inflammatory response in the human body. Since, it is an opportunistic pathogen is will not always harm our body. But if it turns out to be damaging the body, the immune system will recognize it and form antibodies against it.
Q. If we want to prove that particular group or species they are responsible for diabetes or obesity what kind of experiment we can do to prove this?
ReplyDeleteAns. We can use germ free mice for such purpose germ free mice means gnotobiotic mice which are free from any microbiota of their own. Like Suppose that the mixer of A, B and C that is associate with obesity , Take a mixer of A, B and C then inject to germ free mice and then on those mice develop obesity you concluding say that the present of these three microbiome will make a person more to obesity this is a straight forward example but then negative result In case of negative result in such experiment the interpretation become more truth because in real life the microbiome is not made up of two or three species,It is few hundred species now the present of those hundred species along with genetic and environmental factor to diet that is going to decide the final outcome so it is almost impossible to reproduce those condition in gnotobiotic mice So negative result in such experiment consider difficult to interpret particularly when you took at the fact the human and mice are similar there are large difference on genetic and physiology different so for that we need to select a model or a animal model which is more closely associate with human one option is pig Gnotobiotic pigs they provide better physiology model suppose it is not as good as Human but may be better than mice.
FUNCTIONAL FOOD:
ReplyDeleteFunctional foods are foods that have potentially positive effect on health beyond basic nutrition. They promote optimal health and help reduce the risk of disease.
These foods contain biologically active substances such as antioxidants
Functional foods are generally separated into two categories: conventional and modified
Conventional foods are natural, whole-food ingredients that are rich in important nutrients like vitamins, minerals, antioxidants, and heart-healthy fats.
Examples: Fruits, vegetables, nuts legumes etc.
Modified foods have been fortified with additional ingredients, such as vitamins, minerals, probiotics, or fiber, to increase a food’s health benefits.
Examples: fortified juices,fortified milk alternatives, such as almond, rice, coconut, and cashew milk etc.
Replacement Therapy:
ReplyDeleteThe basis of replacement therapy is the implantation and persistence within the normal microflora of relatively innocuous 'effector' bacteria that can competitively exclude or prevent the outgrowth of potentially disease- causing bacteria, without significantly disturbing the balance of the existing microbial ecosystem.
It is also referred to as “bacteriotherapy” or “bacterial interference".
they involve the use of live microbes for the prevention or treatment of an infectious disease same like probiotics but replacement therapy involves a dramatic and long-term change in the indigenous microbiota of a site, whereas this is not the case with probiotics always.
it has a minimal immunological impact.
Bioactive natural products (BIONPs) -these are compounds mainly obtained from plants with a very wide range of biological activities like antimicrobial, anti-inflammatory, antioxidant, immunomodulatory, antidepressant, antihyperglycaemic (amylase activity), antihypertensive, anticarcinogenic, etc.
ReplyDeleteThese BIONPs are used as plant extracts or fractions.
BIONPs compounds limitations-due to their low availability and stability, high volatility, and a great diffusion ability they are not recommended for implementation in the current medical practice.
Bioactive compounds includes polyphenols, carotenoids, vitamins, omega-3 fatty acids, organic acids, and phytosterols.
Effector organisms/strains: In Replacement therapy , specific organism are used to prevent the colonisation of a site by a potentially pathogenic species or to displace such a species from the site, these are called as effector strain.
ReplyDeleteThe effector strain used in replacement therapy is thought to cause a long-term change in the indigenous microbiota of a site , it can be naturally occurring or laboratory-derived effector strain.
It effects by following mechanisms like by blocking attachment sites, competing for essential nutrients, and producing inhibitory or cidal compounds, thus protects the host for as long as the it persists as a member of the indigenous microbiota.
The ideal characteristics of an effector organism is:
It must not cause disease itself or otherwise predispose the host to other disease states by disrupting the ecosystem in which it resides.
It should be active specifically against the target pathogen(s)
Should be susceptible to low-risk antibiotics, such as penicillin, so that it can later be eliminated if necessary.
Easy to grow and can be produced in a stable form for distribution.
Easy to identify among the indigenous microbiota of the host
It is necessary that it does not cause systemic toxicity or immunological sensitisation in the host.
Capable of persisting in the host.
Example:An effector strain has been constructed for use in the replacement therapy of dental caries.By using Recombinant DNA methods, the Streptococcus mutans supercolonizing strain, JH1140, lactate dehydrogenase deficient by deleting virtually all of the ldh open reading frame (ORF)is made. And To compensate for the resulting metabolic imbalance, a supplemental alcohol dehydrogenase activity was introduced by substituting the adhB ORF from Zymomonas mobilis in place of the deleted ldh ORF. The resulting clone, was found to produce no detectable lactic acid during growth on a variety of carbon sources, and it produced significantly less total acid due to its increased production of ethanol and acetoin.
What are Functional Foods?
ReplyDeleteThis comment has been removed by the author.
DeleteFunctional foods are ingredients that offer health benefits that extend beyond their nutritional value. Some types contain supplements or other additional ingredients designed to improve health.
DeleteThe concept originated in Japan in the 1980s when government agencies started approving foods with proven benefits in an effort to better the health of the general population (1Trusted Source).
Some examples include foods fortified with vitamins, minerals, probiotics, or fiber. Nutrient-rich ingredients like fruits, vegetables, nuts, seeds, and grains are often considered functional foods as well.
Functional foods are generally separated into two categories: conventional and modified.
Functional foods are foods that have a potentially positive effect on health beyond basic nutrition. Proponents of functional foods say they promote optimal health and help reduce the risk of disease.
DeleteA familiar example of a functional food is oatmeal because it contains soluble fiber that can help lower cholesterol levels.
Functional foods are foods that contain bioactive compounds naturally. Significantly, these foods can provide health benefits beyond the traditional nutritional value of the food.The traditional nutrients refer to the regular vitamins and minerals found in that particular food. Generally, traditional nutrients are essential to the diet, and their deficiency causes classical nutrient deficiency diseases. That means the functional foods contain a unique form of nutrient, which in turn promote the health.In other words, vitamin C in orange prevents scurvy. On the other hand, vitamin D in sardine can alleviate rickets. However, both vitamin C and vitamin D are essential nutrients. Therefore, neither orange nor sardine becomes a functional food. For instance, soy protein has a function in reducing cardiovascular disease. But since soy protein is not an essential nutrient in the diet, soy is a type of functional food. Likewise, red grapes containing phytochemical resveratrol, cranberry juice containing oligomeric proanthocyanidins, oat bran containing fiber, and barley containing beta-glucan are functional foods.
DeleteFunctional foods are foods that have a potentially positive effect on health beyond basic nutrition. Proponents of functional foods say they promote optimal health and help reduce the risk of disease.
DeleteA familiar example of a functional food is oatmeal because it contains soluble fiber that can help lower cholesterol levels. They contain a type of fiber called beta glucan, which has been shown to reduce inflammation, enhance immune function, and improve heart health
Some foods are modified to have health benefits. An example is orange juice that's been fortified with calcium for bone health.
Functional food is a food claimed to have an additional function by adding new ingredients or more of existing ingredients.
DeleteIdea was first described In the ancient Vedic texts from India, and in ChineseTraditional medicine. The vision to develop functional foods reflects the oriental philosophy that: ‘Medicine and food have a common origin’.
Today, Japan is the only country that recognizes functional Foods as a distinct category, and the Japanese functional food Market is now one of the most advanced in the world. Known as foods for specified health use (FOSHU).
Categories of functional foods:
Processed foods with added ingredients like Calcium-enriched fruit juice
Basic food like Carrots (containing the anti-oxidant b-carotene)
Processed foods like oat bran cereal.
Isolated, purified preparations of active food ingredients like b-Glucan from oat bran.
Food enhanced to have more of a functional component like Tomatoes with a higher levels of lycopene.
Reference : DOI: 10.1038/ejcn.2010.101
Nutraceuticals:
ReplyDeleteMedicinally or nutritionally functional food.
Nutraceuticals are the products derived from food sources with extra health benefits in addition to the basic nutritional value found in food.
Neutraceuticals are the bioactive compounds found in fortified food, dietary supplements, and herbal products. However, they are often defined synonymously with functional foods due to the presence of a specific nutrient in a particular food. Some examples of nutraceuticals in fortified food are the calcium fortified in orange juice and vitamin D fortified in milk.
DeleteNutraceuticals are products that are used for both nutrition and medicine. A substance that has physiological benefit or provides protection against chronic disease is referred to as a nutraceutical product. Nutraceuticals can be used to promote health, slow down the ageing process, prevent chronic diseases, extend life, and maintain the body's structure and function. Nutraceuticals have recently attracted a lot of attention due to its potential nutritional, safety, and therapeutic benefits.
DeleteNeutraceuticals are defined as food, or parts of food, that provide medical or health benefits, including the prevention and treatment of disease.
DeleteExample of such food includes fortified dairy products, citrus fruits, beet, spinach, garlic capsules etc.
Prebiotics, Probiotics, antioxidants, dietary fibres all are various types of Neutraceuticals.
What is meant by selective toxicity?
ReplyDeleteThe aim of antimicrobial therapy is to kill or inhibit the infecting organism without damaging the host; this is known as selective toxicity. This is commonly accomplished through the use of antimicrobial drugs.
The aim of selective toxicity means that pharmaceutical companies developing antimicrobials have to identify structures or metabolic processes in the microorganism that is different to or absent from the host.
Selective toxicity refers to:
DeleteAntimicrobials that are toxic to both human and microbial cells
Antimicrobials that are toxic to neither human or microbial cells
Antimicrobials that are more toxic to human than microbial cells
Antimicrobials that are more toxic to microbial than human cells
Selective toxicity against microbes means killing the microbial cells but not the host's cells.Antibiotics are antimicrobial agents which were originally defined as the substances produced by microorganisms that inhibit other microorganisms.Antimicrobial drugs are chemicals that are intended to have selective toxicity against microbes, meaning that they kill microbial cells but not the host's cells.Antimicrobial drugs include antibiotics, which were originally defined as substances produced by microorganisms that inhibit other microorganisms.
DeleteSelective toxicity is an important characteristic of an antimicrobial treatment, which means that it selectively kills or slows the growth of microbial targets while inflicting little or no harm to the host. In comparison to fungi, parasites, and viruses, most antimicrobial medicines now in clinical use are antibacterial. This is because the prokaryotic cell affords a broader diversity of distinct targets for selective toxicity. Each antibacterial medication class has its own mechanism of action (the way in which a drug affects microbes at the cellular level).
DeleteWhat are Riboswitches?
ReplyDeleteRiboswitches 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. The typical riboswitch contains two distinct functional domains. 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 discriminate between chemically related metabolites with high selectivity to elicit the appropriate regulatory response. A second domain, the expression platform, contains a secondary structural switch that 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.
The function of riboswitches is tied to the ability of RNA to form a diversity of structures. The most basic of these is the double-stranded helix, similar to that found in DNA. Riboswitches are composed of two domains: the aptamer domain and the expression platform.Riboswitches are organized into families and classes according to two features: the type of ligand they bind, and their secondary structure.
DeleteThe term riboswitch was used to define RNAs that control gene expression by binding metabolites without the need for protein factors or a protein-independent gene regulation mechanism.
DeleteRiboswitches form highly specific binding pockets for the target metabolite and undergo allosteric changes in structure.
Transcription termination in bacteria is a classical example of riboswitch in action.
The most widespread riboswitch class discovered to date responds to the coenzyme thiamin pyrophosphate (TPP) this riboswitch is quite common in plants and fungi.
Common ligands that are sensed by riboswitches; includes magnesium ions, nucleic acid precursors, enzyme cofactors, and amino acid residues. 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.
Riboswitches are small molecule ligand-binding elements present in the 5′-untranslated region (UTR) of mRNAs that exert regulatory control over the transcript in a cis-fashion. A typical riboswitch is made up of two functional domains. An aptamer domain recognises the effector molecule and folds into a compact three-dimensional fold to scaffold the ligand binding pocket. To elicit the right regulatory response, these RNA receptors, like proteins, must discriminate between chemically similar compounds with high selectivity.A secondary structural switch interfaces with the transcriptional or translational machinery in a second domain, the expression platform. The switching sequence, an area of overlap between these two domains that controls 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, is responsible for regulation.
DeleteA riboswitch is a cis-regulatory RNA element that regulates downstream or upstream gene expression in response to a specific ligand molecule. The ability of RNA to create a variety of forms is linked to riboswitches' activity. The 5' untranslated region (5' UTR; a segment of RNA preceding the translation start site) of bacterial mRNA is where riboswitches are most frequently found. They control the occlusion of transcription repression or translation start signals. The thiamine pyrophosphate (TPP) riboswitch affects splicing at the 3' end of certain eukaryotic mRNA. Inhibitors of riboswitches have a low efficacy rate.
DeleteRiboswitches are structural RNA elements found in the 5' untranslated regions of certain mRNAs that control gene expression by terminating transcription prematurely or suppressing translation initiation. The functional domains of a typical riboswitch are two. An aptamer domain detects the effector chemical. The expression platform, a second domain, communicates with the transcriptional and translational machinery. The switching sequence, which spans these two domains and drives RNA folding into one of two mutually incompatible configurations in the expression platform that represent the on and off states of the mrna, is responsible for regulation.
DeleteRiboswitches : it is a common RNA regulatory element .Riboswitches are structured noncoding RNA domains that selectively bind metabolites and control gene expression . Riboswitches, RNA elements found in the untranslated region, regulate gene expression by binding to target metaboloites with exquisite specificity.
ReplyDeleteWhat is Differences Between Antigenic Shift and Antigenic Drift??
ReplyDeleteANTIGENIC DRIFT:
Deletemutations which produce small changes in antigenic drift and these occur in same strain.
The variation in the antigenic pool is by accumulation of gene mutations.
The change is gradual.
Result in new viral strain.
Occurs frequently.
Easy to treat it.
Example, occurs in influenza virus A,B and C, HIV.
May infect animals of the same species.
Usually responsible for epidemics in between pandemics.
ANTIGENIC SHIFT:
Mutations which result in a major change and produce new strains are referred to as antigenic shift.
Two different strains of viruses combine to form a new subtype.
The change is sudden and drastic.
Result in a new subtype of the virus.
Occurs once in time.
Difficult to treat.
Example: occurs in influenza virus A.
Give rise to pandemics, which occurs irregularly and unpredictably.
1) Antigenic Shift : Antigenic shift refers to the gene recombination occurring when influenza viruses re-assort. It is major Antigenic Change. Large change in nucleotides of RNA. It results from Genome re-assortment between different subtypes. It occurs only in Influenza Virus A.
Delete2) Antigenic drift : Mutations causing minute changes in the hemagglutinin and neuraminidase antigens on the surface of the Influenza virus is termed antigenic drift. It results due to accumulation of point mutations in the gene. Small mutation of RNA. It occurs in Influenza Virus A, B and C.
Antigenic drift involves the accumulation of a series of minor genetic mutations. Antigenic shift involves “mixing” of genes from influenza viruses from different species.
DeleteThe main difference between antigenic drift and antigenic shift is that antigenic drift is a mechanism for variation in viruses by accumulating mutations within genes, which code for antigen-binding sites whereas antigenic shift is a process of combining two types of viruses to form a new subtype with a mixture of surface antigens of the original viruses.
DeleteAntigenic drift is the result of a sequence of small genetic changes accumulating over time.
DeleteAntigenic shift occurs when genes from various influenza viruses are mixed
Antigenic drift: As the influenza virus reproduces, its genes change slightly. Over time, these small changes accumulate, so that your immune system becomes less effective at protecting you from the virus. Antibodies now have trouble recognizing the changed virus. This is called antigenic drift.
DeleteAntigenic Shift: Both human and bird influenza viruses can attach to and enter the lung cells of a pig. During replication, both versions of influenza virus release their genetic material into the pig cell. Then, the genes from the different viruses can “mix” creating new versions of influenza virus. Because the genes in the resulting virus are dramatically different, this is called antigenic shift.
Antigenic shift can produce a version of influenza virus that no person’s immune system has antibodies to protect against. This is when an influenza pandemic can occur.
Antigenic drift is a minor antigenic change resulting in a new strain of virus while the antigenic shift is a major antigenic change, resulting in a new subtype.
DeleteWhich the glycoprotein present on surface of Influenza A viruses?
ReplyDeleteTwo glycoproteins on the surface of influenza virus, hemagglutinin and neuraminidase, play a role in the process of influenza virus infection and release.
DeleteHemagglutinin (HA) of the trimer and neuraminidase (NA) of the tetramer are two glycoproteins on the IAV surface. They play an important role in the process of virus infection and escape, each with high variability owing to adaption to environmental changes and host immune escape response.
DeleteHaemaglutinin (HA) and Neuraminidase (NA) two well-known glycoproteins found on the surface of the Influenza A virus are important molecules for viral infection that bind to Sialic acid.
DeleteThe influenza virus major surface glycoproteins, hemagglutinin (HA), and neuraminidase (NA) dominate the virion surface and form the main targets for these neutralizing antibodies. In addition to the mutations that arise due to antigenic drift, the HA and NA of influenza A viruses (IAVs) can exist in different forms.
DeleteWhat is work of neuraminidase (NA) glycoprotein in Influenza A viruses ?
ReplyDeleteneuraminidase is an enzyme that is essential for release of progeny virus particles from the surface of an infected cell.
DeleteInfluenza virus neuraminidase cleaves sialic acid groups from cell glycoproteins, enabling release of the virus from host cells. Neuraminidase also contributes to virus binding to the sialic acid groups of cell glycoproteins, which could complement the receptor-binding function of hemagglutinin, enhancing enzymatic activities of neuraminidase, and facilitate virus infection.
DeleteNeuraminidase(NA) activity in the IAV infection cycle has primarily been limited to assisting virion progeny egress from infected cells. NA interacts with sialic acid, a terminal structure linked to underlying sugar residues expressed at the cell surface by glycoproteins or glycolipids. In the last stages of infection, NA plays a critical role. Viral NA removes sialic acids from cellular receptors as well as newly generated NA on nascent virions that have been sialylated as part of the host cells glycosylation processes. Virion aggregation is prevented by NA cleavage of sialic acids which also hinders virus attachment to the dying host cell.
DeleteDrugs called neuraminidase inhibitors, which include oseltamivir (Tamiflu) and zanamivir (Relenza), inhibit the release of influenza A and B viruses from host cells. This inhibition stops the process of viral replication. Neuraminidase inhibitors are commonly used in both the prevention and the treatment of influenza.Influenza and its interactions The interaction of viral glycoproteins with cell surface receptors is a key factor in infectivity and thus transmissibility. Understanding these connections is crucial for determining which criteria are required to predict pandemic risk. Influenza The hemagglutinin (HA) glycoprotein is responsible for virus attachment to cell surface sialic acid receptors, while the neuraminidase (NA) glycoprotein is responsible for cleaving the receptor to allow virus release. Previous research has shown that NA proteins of the N9 subtype can bind sialic acid through a different binding site from the active site of sialidase.
DeleteAn important function of the NA protein is to remove sialic acid from glycoproteins. Sialic acid is present on many cell surface proteins as well as on the viral glycoproteins; it is the cell receptor to which influenza virus attaches via the HA protein. The sialic acids on the HA and NA are removed as the proteins move to the cell surface through the secretory pathway. Newly released virus particles can still potentially aggregate by binding of an HA to sialic acid present on the cell surface. Years ago Peter Palese showed that influenza virus forms aggregates at the cell surface when the viral neuraminidase is inactivated. The NA is therefore an enzyme that is essential for release of progeny virus particles from the surface of an infected cell.
Deletewho is known as father of virology ?
ReplyDeleteMartinus Beijerinck is the Father of Virology. He was a Dutch microbiologist who was the first person to use the term "virus".
DeleteHe originated selective culture techniques, also known as enrichment culturing, and was the first to isolate a wide range of microorganisms.
Martinus Beijerinck is often called the Father of Virology.
DeleteIn 1892, Dmitri Ivanovsky used one of these filters to show that sap from a diseased tobacco plant remained infectious to healthy tobacco plants despite having been filtered.
Martinus Beijerinck called the filtered, infectious substance a ‘virus’ and this discovery is considered to be the beginning of virology.
What do you mean by Malaria paroxysm ?
ReplyDeleteAs the disease progresses, some patients may develop the classic malaria paroxysm with bouts of illness alternating with symptom-free periods. The malaria paroxysm comprises three successive stages. The first is a 15-to-60 minute cold stage characterized by shivering and a feeling of cold. Next comes the 2-to-6 hour hot stage, in which there is fever, sometimes reaching 41°C, flushed, dry skin, and often headache, nausea, and vomiting. Finally, there is the 2-to-4 hour sweating stage during which the fever drops rapidly and the patient sweats.
Malaria paroxysms are antiparasite responses in Plasmodium vivax malaria that while painful to the human host, almost never result in serious acute pathology.The malaria paroxysm is divided into three stages. Shivering and a sensation of cold characterise the initial stage, which lasts 15 to 60 minutes. The next stage is the 2-to-6-hour hot stage, which includes a fever (up to 41°C), flushed, dry skin, headache, nausea, and vomiting.
DeleteSome patients may acquire the characteristic malaria paroxysm as the disease progresses, with periods of illness interspersed with symptom-free periods. The three stages of the malaria paroxysm are as follows: The first stage is a 15-to-60-minute chilly period marked by shivering and a cold sensation. Then there's the 2-to-6-hour hot stage, which includes a fever (up to 41°C), flushed, dry skin, headache, nausea, and vomiting. Finally, there occurs the 2-to-4-hour sweating stage, during which the patient's fever rapidly decreases and he or she sweats profusely.
DeleteParoxysm is an acute fever that is typically preceded by chills and rigor. It occurs during various types of microbial infection, malaria being one of them. The malaria paroxysm comprises three successive stages. The first is a 15-to-60 minute cold stage characterized by shivering and a feeling of cold. Next comes the 2-to-6 hour hot stage, in which there is fever, sometimes reaching 41°C, flushed, dry skin, and often headache, nausea, and vomiting. Finally, there is the 2-to-4 hour sweating stage during which the fever drops rapidly and the patient sweats.
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ReplyDeleteQues- What is the difference between probiotics and prebiotics?
ReplyDeleteAns: Probiotics are 'living' friendly bacteria that are comparable to those that live in our intestines. They can be found naturally in cultured or fermented foods including yoghurt, buttermilk, aged cheese, sauerkraut, sourdough bread, miso, tempeh, and kombucha, a type of fermented tea, as well as taken as a supplement. Probiotics aid in the maintenance of healthy quantities of good bacteria in the intestines, strengthen our immune systems, are beneficial to anyone suffering from bloating, gas, or flatulence, and may help shorten the duration of diarrhoea in children.They may also aid in the recovery of beneficial bacteria following antibiotic treatment. Probiotics come in a variety of forms, each with its own set of characteristics. Lactobacillus acidophilus and bifidibacterium lactis, which are commonly found in yoghurt, may be familiar to you.
Prebiotics are 'nonliving' food elements that bypass digestion and reach the large intestine, where they 'feed' the good bacteria in our gut, allowing them to grow and thrive. Many foods naturally contain prebiotics such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS), such as: Legumes,Products made from whole wheat, Foods made with rye, Artichokes/Onions, Cabbage,Garlic,Chicory is a type of root vegetable.
Q.Describe the term Dysbiosis?
ReplyDeleteAns.Dysbiosis is a term used to describe a "imbalance" in the gut microbiota that is linked to disease. This imbalance could be caused by changes in the relative abundance of microorganisms or by the addition or removal of community members.
Dysbiosis is a misalignment of commensal flora with respect to the individual organism's endobiogenic demands.
This imbalance could be caused by one of three factors:
(1) a lack of commensal flora
(2) a reduction of variety in the normal commensal flora &
(3) pathogenic flora competing with the commensal microbiome.
Exposure to different environmental factors, including as nutrition, chemicals, medicines, and viruses, can cause changes in the microbiota.
Dysbiosis of the gut microbiota is increasingly being linked to the aetiology of both intestinal and extraintestinal illnesses. Irritable bowel syndrome (IBS), celiac disease, and inflammatory bowel disease are examples of intestinal illnesses, while allergies, asthma, metabolic syndrome, cardiovascular disease, and obesity are examples of extra-intestinal disorders.
Dysbiosis is a condition in which the gut bacteria become imbalanced.
DeleteFactor for dysbiosis:
excessive or wrong use of antibiotics, excessive alcohol consumption, increased intake of sugar or protein,chronic stress. poor dental hygiene and anxiety.
Diagnosis:
Comprehensive Digestive Stool Analysis.
Biopsy
Development of resistance is advantageous to pathogen or not?
ReplyDeletePathogen develops resistance against drug so that it can survive there for long time so in this context resistant development seems to be advantageous,
While to gain resistance bacteria need to invest energy ( add genes ), May expriance genetic burden also so in this aspect it dose not seems to be advantageous, and that's why antivirulence agents are emerging strategies as they provide an option of survival without this energy investment.
Whether signal supply inhibitor or signal response inhibitors are of benefit to us?
ReplyDeleteSignal supply inhibitors can't stop 100% production of signal, while signal response inhibitors won't stop production but makes production useless as they will compromise the cell's ability to respond to signal and so most of the cells will behave as signal blind,
If cell's won't have signal response ability they can't participate in quorum sensing which is not true in case of signal supply inhibitors,( if cell's don't have ability for signal production still can participate in quorum sensing) ,
so may be signal response inhibitors are good strategy to use.
Whenever we feel fever, our body temperature is high but we feel cold instead of feeling hot? Why this is so?
ReplyDeleteIt's a natural physiological reaction. When your brain raises its internal thermostat to combat an infection, the rest of your body works overtime to generate extra heat to keep up with the higher temperature.
DeleteIt’s actually a normal physiological response. As soon as your brain shifts its internal thermostat to a higher set point to fight off an infection, the rest of your body goes to work trying to generate extra heat to meet that higher temperature goal. Suddenly, you’re technically below your new “ideal” core temperature, so you feel cold.
DeleteWhich pathogenicity strategyy is smarter, acute or chronic?
ReplyDeleteAcute infection strategy is smarter than chronic.
In chronic infection the infectious agent stay in host for long time and in acute infection infectious agent kills the host (the source of nutrition)
In acute infection bacteria grows much faster compared to chronic infection, replicate more faster, successful transmission.
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ReplyDeleteSometimes drugs used in prophylaxis also used in treatment,(for example in malaria) ,is it good ?
ReplyDeleteDo all pathogens have PAI ?if not, Is there any advantage of not having PAI?
ReplyDeleteIt is not necessary that all pathogens have PAI, some may have lost it, this may be due to it's habitat, (diversity)
Genome reduction helps it to become more specific to particular organ.
Example: H. Pylori have lost some genes so it's genetic burden is less so it will become specific for that host.
Which antifungal are to be used for mucormycosis?
ReplyDeleteAmphotericin B (Amb) is one of the oldest known effective antifungal agents the current guideline for the treatment for mucormycosis they recommend use of antifungal treatment along with surgical debridement direction of correction of risk factor (correction of risk factor means the person is suffering from high sugar then while treating him for mucormycosis the initial also try to to control the sugar) Surgical debridement refers to removal of the part of tissue which is infected by the mucor but surgical debridement has quite effective an extensive repeated surgical processes may be recommended to achieve local control and improve outcome and that can be heavy on the patient. Surgery may be an option for such certain body sides crucial but the infection in the nasal cavity or in the eyes or in the nervous system then the surgery remains the compulsory option in the case of post mucormycosis surgery is mandatory.
Amphotericin B along with Liquid formulation, Liquid formulation of Amphotericin B considered to be superior and another antibiotic known as Posaconazole are the only antifungal drug available in vitro and in vivo activity against mucorales. Posaconazole have at least three antibiotics known to be capable working against mucor.
How does a microbe like P. Aeruginosa make a decision regarding causing acute versus chronic disease?
ReplyDeleteBacteria either initiate an acute infection via variables such as TTSS and different toxins, or build a chronic, biofilm-like infection in response to unidentified signals.The infection's point of entrance may influence whether it becomes acute or chronic.When developing in the CF lung,P.aeruginosa appears to be growing in a biofilm-like fashion.This growth approach may be the result of specific environmental signals and/or host factors found in the lungs of patients with this condition.Other factors,such as the host's immunological status,tissue integrity, and patient nutrition,could influence whether microorganisms start an acute or chronic infection.
Mucormycosis an example of fungal pathogen
ReplyDeleteIt is one of the most recent problems reported by widely reported widely with coronavirus infection, the considerable number of coronavirus patient stay becomes susceptible to the fungi called mucor in fact it is not the single fungus group which is known as mucorales group which includes rizosphere as well as mucus fungi has not primary involved to the pathogens they have evolved to leave the saprophytic life for free human life so fungi has not been major cause of mortality and morbidity till the recent news but now we are having some member in the human population who are organ transplantation for condition like HIV infection making them immunocompromised and in those cases even the pathogens who are not mainstream profession pathogens they can also cause the infection what we called as secondary infection of opportunities for a pathogen so earlier se to the lesser incidence of fungal infection not much attention was paid to discovery of antifungal agents even today we have very small number of antifungal agents available in general for example some of the azoles or amphoteric compounds we have general it is difficult to the antibiotic against fungi because funge are eukaryote and human host are also eukaryote so if target something in fungi is high probability that the antifungal agent target the same thing in humans for example if we stop.Protein synthesis inhibiting ribosome.Ribosomes are ATS fungi as well as human so the criteria of selective toxicity very difficult to achieve only certain things chitin cell wall they can be targeted from they are absent from human system you know you human cell like any other animal cell do not contain cell wall that so that you can target that they have a cell wall but they do share the machinery like mitochondria ribosome cell membrane so it does difficult and most of the antifungal are most toxic are the side effects of of the antifungal treatment are sometimes it use effectively and initially and when we say it is not sufficient to you hospital facility suffering from primary infection to die and the number of living immunocompromised people must be less since we have more advanced facilities in last 10-20 years the number of immunocompromised people in the living condition for example those living after normal organ transplantation and also after having AIDS they still continue the life that means overall se the life expectancy has increased for example in India was below 50 at the time of independence now it is around 67 that means the more number of elderly people more number of immunocompromised people who are are already having compromised system or or infected by some infection so fungi make them easy target so the probability of the secondary infection by the opportunistic infection has increased the strange rise by the side effect of of advance medical sciences and facilities.