Probiotics and its mechanism

Prebiotics and Probiotics and their mechanism against pathogens in our body.

1. Probiotics and its mechanistic behaviour against pathogens Submitted to:Dr Manjit mam Submitted by:Komal Btech biotech 3 rd year 1800108006

2. Prebiotics Prebiotics are plant-derived polysaccharides that act as food and fuel for probiotics . These include inulin , nonstarch polysaccharides found in some cereal grains and seaweed or algae, disaccharides ( lactulose ), and polysaccharides including fructooligosaccharides ( fos ) and galactooligosaccharides .

3. Present in Vegetables : Artichokes , Garlics , Onions- shallots, and spring onions, Leeks, Savoy cabbage Legumes : Red kidney beans, Baked beans, and Soybeans, Chickpeas Fruits : Bananas, Custard apples, watermelon, Grapefruits, nectarines, white peaches Cereal grains : Bran, Barley, Oats Nuts & Seeds : Almonds, Flaxseeds, Pistachio nuts

4. Cont… Prebiotics are fermented by colonic bacteria, generating end-products such as SCFAs that provide essential nutrients for the enteric epithelium. They also induce anti-inflammatory regulatory T cells ( T regs ), and lower luminal Ph Prebiotics are also speculated to protect the gut epithelium by increasing the mucus layer, elongating the microvilli , increasing numbers of epithelial cells, and by preventing adherence of pathogenic strains to the epithelial cells. Other SCFAs such as propionate appear to induce de novo generation of T regs in the peripheral immune system. A newly published study in mice revealed that when deprived of fiber , commensal bacteria will degrade the protective mucosal mucus layer, permitting invasion by commensals and pathogens alike. Probiotic therapies can provide benefits independent of diet.

5. Probiotics As defined by the Food and Agriculture Organization of the United Nations(FAO) and the World Health Organization(WHO) in 2002, probiotics are : “Live micro-organisms which when administered in adequate amounts confer a health benefit on the host.” Probiotics are friendly bacteria or yeasts are a concept in contrast to antibiotics. Lactobacilli and Bifidobacteria are the most common probiotics bacteria but the yeast Saccharomyces cerevisiae and some Escherichia coli strains are also used as probiotics . Lactobacillus--- ( L. casei , L. plantarum , L. acidophilus, L. bulgaricus ) Bifidobacterium --- ( B. longum , B. breve , B. infantis ) Additional microbes: Bacillus and Streptococcus Yeast - Saccharomyces boulardii

6. Lactobacilli Lactobacilli are Gram-positive, non-spore forming rods or coccobacilli . They are found in a variety of habitats where rich, carbohydrate containing substrates are available, such as human and animal mucosal membranes, on plants or material of plant origin, sewage and fermenting or spoilt food. Lactobacilli are normally found in the intestine of infants in high numbers, but decline rapidly after infancy.

7. Lactobacillus casei strain SHIROTA Lactobacillus casei In 1930, Minoru Shirota successfully cultured a bacterial strain that was able to survive throughout the intestines. This strain, selected from a large collection of lactic acid bacteria was later named as Lcatobacillus casei strain Shirota and found to act as a probiotic agent. It is broadly distributed in nature and isolated from dairy products,silage and the intestinal tracts of various animals. It is suggested to have a wide range of pH and temp. and most common application in industrial, specially for dairy production. it’s dominant species of nonstarter lactic acid bacteria used in the manufacture of fermented dairy beverages.

8. Bifidobacteria Bifidobacteria are non-motile, non- sporulating Gram-positive rods with varying appearance. Most strains are strictly anaerobic. They constitute a major part of the normal intestinal microflora in humans, appearing in the stools a few days after birth and increasing in number thereafter. The number of bifidobacteria in the colon of young children is high, but this number decreases rapidly with age.

9. Probiotics cont.. Probiotics must survive the acidic environment of the stomach and bile acid to colonize the intestines. Probiotics appear to confer benefits without changing the microbiome permanently and transient colonization is still associated with beneficial effects in the host. Probiotics , through secreted molecules, influence the innate inflammatory response of epithelial cells to stimuli from the gut lumen, and reduce mucosal inflammation. Probiotics have implications for the treatment of several gastrointestinal diseases including antibiotic-associated colitis, acute gastroenteritis, inflammatory bowel disease, colon cancer, and irritable bowel syndrome.

10. Probiotic concentration in human digestive system

11. Mechanisms through which probiotics improve host health : Reducing intestinal permeability by upregulation of tight junction proteins. Increasing mucin secretion by goblet cells. Increasing secretion of defensins which prevent pathogen colonization, Production of scfas , stimulation of iga secretion. Decreasing luminal ph, and enhancing and directing immune cells to promote tolerance to commensals while maintaining protection against pathogens. Even nonviable organisms might confer health benefits by adhering to the mucus layer and stimulating immune function in dogs. Capsular polysaccharide from bacteroides fragilis , for instance, activates t regs and decreases severity of colitis in mice .

12. Mechanisms of pathogen, inhibition by LAB- probiotics

13. Probiotics help in Modulation of gut microbiota i.e. increased beneficial bacteria and decreased pathogenic bacteria Improvement of colonic physico -chemical conditions: decreased pH, improved fermentation Reinforce gut epithelial barrier: ↑ Defensins and mucus production by goblet cells ↑Permeability ↑ Cytoprotective heat-shock proteins ↓ Bacteria producing harmful enzymes:

14. Cont.. Binding, deactivation of carcinogens:↑Detoxifying enzymatic antioxidants: GTS, glutathione, glutathione reductase , Glutathione peroxidase , superoxide dismutase and catalase Anti-carcinogenic metabolites: SCFAs, CLAs, phenols; ↑Apoptosis; ↑Differentiation in cancer cells ↓Intestinal inflammation: ↓TLR-4, ↑IL-10, IL-8 secretion, NF- kB activation immune response against tumour cells: ↑TNF and NO production in epithelial cells ↑Regulatory T-cell activity ↑Bactericidal phagocytic activities of neutrophils↑IL-12, stimulation of DCs and NK cells  

15. Cont.. Improvement in autoimmune arthritis after supplementation with live cultures of Streptococcus lacticus and Bacillus bulgaricus was reported in 1909. Bifidobacterium longum ssp. longum (JCM 1217) has been shown to protect against E. Coli O157:H7-induced enteropathogenic infection in mice. Streptococcus salivaris termed VSL#3 - humans with ulcerative colitis Lactobacillus rhamnosus was associated with decreased duration of diarrhea compared with a placebo. A small clinical trial with a probiotic strain of Saccharomyces boulardii improved clinical signs in dogs with IBD and protein losing enteropathy . Enterococcus faecium SF68 is a lactic acid-producing strain that has been shown to increase antibody secretion in mice with Giardiasis as well as decrease fecal shedding of Giardia . It is associated with increased serum IgA levels & significantly decreased the incidence of diarrhea . Also, there was also a decrease in fecal C. perfringens and an increase in Bifidobacteria associated with probiotic administration.

16. Cont.. multispecies symbiotic containing Enterococcus faecium , Bacillus coagulans , and Lactobacillus acidophilus , along with prebiotics , improved fecal scores and reduced the incidence of diarrhea Evidence of the role of probiotics in treatment of CRC have been reported as LAB play a key role in In modulating the microbiota , In improving the physico -chemical conditions of the gut and In reducing oxidative stress. Probiotic formulations have shown great promise in CRC as preventive, early stage therapeutics and their role in modulating the microbiota , in improving the physico -chemical conditions of the gut and in reducing oxidative stress. LAB may also modify luminal secretions, reinforce the mucosal barrier, affect epithelial cell proliferation and reduce the exposure to toxic and carcinogenic compounds in the colon.

17. How it function in human body Antibiotic pathogenic bacteria + Probiotic capsule. Harmful organism will be destroyed. Beneficial bacteria multiplies rapidly. Wound healing occur. Healthy immune respon

18. Schematic representation of anti-adhesive properties of probiotics and prebiotics : Pathogens, probiotic and bacterial toxins adhere to cell surface oligosaccharides carried on glycolipids and glycoproteins ; Prebiotic oligosaccharides, particularly galacto -oligosaccharides (GOS) have some structural similarity to cell surface glycoproteins and are postulated to inhibit adhesion of toxins and pathogens to cells; The adhesion of probiotic bacteria to cell surface receptors is postulated to inhibit adhesion of toxins and pathogens to those receptors

19. Beneficial effects due to LAB- probiotics

20. Thankyou