The document discusses the gut microbiome and its impact on human health. The gut microbiota assists with energy harvesting from food, pathogen protection, immune regulation, and strengthening gut barriers. Changes in microbiota composition can affect these functions. The major bacterial phyla in the human gut are Firmicutes, Bacteroidetes, and Actinobacteria, while the genera include Bacteroides, Clostridium, and Bifidobacterium. Dysbiosis is an imbalance in gut bacteria that is associated with disease. Research also suggests that gut bacteria can communicate with and regulate the brain through immune pathways and biochemicals.

1. GUT MICROBIOME
Name – Nimavat Rahulkumar C.
Course – MSc microbiology (SY)
EN.No – 21SOSMB21028
Email – rahulnimavat2311@gmail.com
Institute/University – Department of Microbiology ,
School of Science , RK University , Rajkot.

2. • Introduction
“The gut microbiota is a vast and complex collection of microorganisms that profoundly
affects human health.”
 The gut microbiota assists in a range of bodily functions including….
1. harvesting energy from digested food
2. protecting against pathogens
3. regulating immune function
4. strengthening biochemical barriers of the gut and intestine
 Changes in microbiota composition can affect these functions.
 While there are beneficial bacteria in the gut, there are also harmful bacteria that can enter the GI
tract and cause infection.. These infections include food poisoning and other GI diseases that result
in diarrhea and vomiting.
 In fact, there are roughly 10 time more bacterial cells than human cells in the gastrointestinal system.

3. Major bacterial phyla and genera……
Major bacteria phyla and genera
predominating in human gut microbiota.
Phyla Genera
Firmicutes (60-
80%)
- Ruminococcus
- Clostridium
- Lactobacillus
- Enterococcus
Bacteroidetes (20-
30%)
- Bacteroides
- Prevotella
- Xylamibacter
Actinobacteria
(<10%) - Bifidobacterium
Proteobacteria
(<1%)
- Escherichia
- Enterobacteriacea
e
Good and bad bacteria
Good bacteria – lactobacillus , lactococcus ,streptococcus
thermophilus , propionibacterium , bifidobacterium .
Bad bacteria – salmonella , e.coli ,staphylococcus
,clostridium perfringens , campylobacter .

4. Factor affecting gut microflora
Dysbiosis is often defined as an “imbalance” in the gut microbial community that is associated with disease.
This imbalance could be due to the gain or loss of community members or changes in relative abundance of
microbes.

5. How gut bacteria are controlling your brain…
• Specific gut microbes can modulate the immune system in ways that impact the brain and also produce molecules that
signal directly to neurons to regulate their activity"
• Researchers find that gut microbes can regulate the early development of neurons in ways that lead to lasting impacts on
brain circuits and behaviours.
• she also find that under shorter timescales, gut microbes can regulate the production of biochemicals, like serotonin, that
actively stimulate neuronal activity."
• research suggests our microbes may be communicating with our brains through numerous pathways, from immunity to
biochemicals.
• Much of the research in this field is conducted in mice. And mice, given the mindboggling complexities of establishing
causality between microbial signals and changes in human thought and behaviour,
• animal studies have provided some intriguing insights into the strange interactions between bacteria and brain. Research,
for example, shows that "germ-free" rats and mice are more prone to anxiousness, and less sociable than those with an
intact microbiota. Germ-free mice, and those given antibiotics have also been found to be more hyperactive,prone to risky
behaviour and less able to learn or remember.
• Antibiotics, which can reduce the microbiota in an animal, also reduce shoaling behaviour in zebrafish, while probiotics
boost it.
• Again, the human brain is vastly more complex than that of a rodent or fish, but they do share some similarities and can
offer clues. It makes sense that bacteria, wherever they live, might benefit from helping their hosts to be more sociable
and less anxious.