The document discusses the gut microbiota, highlighting the complexity and significance of the microbial community within the human intestine, which consists of around 100 trillion microbes and plays a crucial role in various body functions. It outlines factors influencing microbiota composition such as age, diet, and geography, as well as its impact on nutrition, immunity, and health disorders like obesity and IBD. The document also touches on the study methods of microbiota, including both culture-dependent and independent techniques.

1. GUT MICROBIOTA
The Human Bacteria

3. Humans as micro biomes:-
- 100 trillion microbes in human intestine.
- 3 million genes (100X).
- 2 kg weight.
- 300-1000 species of bacteria.
- control almost all body functions.

4. COMPOSITION
• 99 % from 30 – 40
species.
• 4 dominant phyla :
- Bacteriodetes.
- Fermicutes.
- Actinobacteria.
- Proteobacteria.
• Enterotypes :
- Prevotella.
- Bacteroides.
- Ruminococcus.

5. Variation of Gut Micro biota :
- Dependence on Age
- Dependence on Geography
- Dependence on Diet

6. Variation with Age

7. Variation with Diet

8. Acquisition Of Micro Biota
• The 1st week bacteria create a
reducing environment.
• Strict anaerobic species genera :
Bifidobacterium, Bacteroides,
Clostridium, and Ruminococcus.
• Breast-fed babies :
Bifidobacteria
• Formula-fed infants :
Enterobacteriaceae,
Enterococci, Bifidobacteria,
Bacteroides, and Clostridia.
• Immune inactivation in early
age.

9. FUNCTIONS

10. NUTRITION
• 30% more calories.
• Short-Chain Fatty Acids (SCFAs)
• SACCHAROLYTIC FERMENTATION
• Acetic acid, Propionic acid and
Butyric acid.
• SCFAs in the caecum. Intestinal
SCFAs directly provide energy to
colonocytes, absorption into the
portal circulation, stimulates
adipogenesis.
• PROTEOLYTIC FERMENTATION
• Collagen and Elastin
• Toxins, Carcinogens, SCFAs

11. TROPHIC EFFECTS
• Growth of intestinal epithelial cells, lymphoid tissue
and control their proliferation and differentiation
• Sodium/Glucose transporters

12. METABOLISM
• Positively control the intestinal epithelial cell
differentiation , proliferation by production of Short-Chain
Fatty Acids.
• Syntheses of vitamins like Biotin and Folic Acid
• Absorption of ions including Magnesium, Calcium and Iron.
• Metabolize dietary carcinogens - Micro components &
Macro components
• Micro - Genotoxic , Heterocyclic Amines (HCAs)
• Macro - Excessive intake of Fat and Sodium Chloride

13. IMMUNITY
• Oral Tolerance
• Immune Exclusion - IgA
• Expression of TLRs

14. PROTECTIVE FUNCTIONS
• Competitive Exclusion by BARRIER EFFECT
• Bacteriocins
• produces lactic acid and fatty acids, serves to
lower the pH in the colon
• In alergic patients, C. difficile and S. aureus are
higher and lower prevalence of Bacteroides and
Bifidobacteria
• Prevention of IBD

15. SPECIATION
• Nasonia giraulti, N. longicornis, N. vitripennis
• Halogenome

17. OBESITY
• fewer Bacteroidetes and more Firmicutes
• differences in the energy-reabsorbing potential
• Roux-en-Y gastric bypass (RYGB)
• Results in significant weight loss improvements
in conditions like Type 2 diabetes.
• 29% of their body weight within 3 weeks, despite
no change in net food intake.

18. IBD
• Ulcerative Colitis and Crohn's disease

19. CANCER
• Bacteroides and Clostridium
• Lactobacillus and Bifidobacteria
TRANSLOCATION
• Too much growth of bacteria in the small intestine
• Reduced immunity of the host
• Increased gut lining permeability in diseases like cirrhosis

20. MENTAL HEALTH
• kids with autism were twice as likely as children with
other types of disorders to have frequent diarrhoea or
colitis
• mice with autism-like symptoms were given a diet with
Bacillus fragilis
• Probiotics have been used to treat Obsessive–Compulsive
Disorder (OCD) and Attention- Deficit/Hyperactivity
Disorder ADHD.
• Anxiety often causes nausea and diarrhoea, and
depression can change appetite.
• sociability and risk taking

21. HEART DISEASE
• Trimethylamine N-oxide (TMAO)
• Atherosclerosis
• L-carnitine & Red Meat.

22. ALTERATIONS

23. ANTIBIOTICS
• Antibiotic-Associated
Diarrhoea (AAD)
• Antibiotic-Resistant bacteria.
• C. difficile and Salmonella
kedougou
• Selective Digestive Tract
Decontamination (SDD)
• Children who were given
antibiotics during the first 6
months of life were more
likely to have a higher body
mass

24. PHARMABIOTICS
• Probiotic bacteria
• Probiotic-derived biologically active metabolites
• Prebiotics
• Synbiotics or genetically modified commensal
bacteria
• IBD, Atopy, Infection, Diarrhoea, Cancer & Arthritis

25. STUDY OF MICROBIOTA

26. TECHNIQUES OF STUDY

27. CULTURE DEPENDENT TECHNIQUES
• cost-effective and reproducible.
• strict anaerobes, and it is estimated that >80% of
the gut micro biota cannot be cultivated under
standard laboratory conditions.

28. CULTURE INDEPENDENT TECHNIQUES
• Molecular-based techniques.
• 16S ribosomal RNA (rRNA) gene.

29. MODELS OF STUDY
• Germ Free Animals
• Mono-, Bi-, Poly- Associated Animals
• Human Flora Associated Animals.

30. ARE WE REALLY MORE OF
BACTERIAL MICROBIOME
THAN MAMMALS?

31. Microbiota as a
FORGOTTEN ORGAN ?

32. What would be the advantage of
unicellular organisms becoming
multi-cellular?

33. What differentiates a multi-cellular
unit from a colony of unicellular
beings living in proximity?

34. Whether this association will evolve
into a more complex system in
further evolution of human
digestive system?