Lecture 9.1: Beneficial Gut Bacteria Flashcards
What is a Microbiota?
Community of microorganisms living in a specific
environment
What is a Microbiome?
The entire collection of the genome elements of specific microbiota
How much does the Human Microbiota/Microbiome weigh?
2-3kg
Name 5 Factors that can affect the Human Microbiota/ Microbiome? (10)
- Genetics
- Environment
- Mode of Birth
- Diet
- Lifestyle
- Hormones
- Industry
- Drugs
- Age
- Geographical Location
What is the Role of Microbes in the Nose? (2)
- Mucus Production
- Antimicrobial Elements
What is the Role of Microbes in the Mouth? (2)
- Assist Digestion
- Ward off pathogens
What is the Role of Microbes in the Lungs?
Lubricate Pulmonary Tissues
What is the Role of Microbes in the Stomach?
Prevents Gastric Complications
What is the Role of Microbes in the Colon?
Digestion of Complex Carbohydrates and Other Molecules
What is the Role of Microbes in the Sexual Organs?
Maintain pH and H2O2 production to kill microbes
What is the Role of Microbes in the Skin? (2)
- Fortify immune system
- Scent production
Dominant Bacteria in the Gut (4 Phyla)
- Firmicutes
- Bacteroidetes
- Actinobacteria
- Proteobacteria
Most bacteria belong to the genera…? (8)
- Bacteroides
- Clostridium
- Fusobacterium
- Eubacterium
- Ruminococcus
- Peptococcus
- Peptostreptococcus
- Bifidobacterium
What are the 3 Classes of Bacteria found in the Gut?
- Beneficial Bacteria
- Harmful Bacteria
- Opportunistic Bacteria
Name 5 Major Roles Of Beneficial Gut Flora (11)
- Digestion and absorption of food
- To break down proteins, carbohydrates, fibre and fats
- To transport vitamins, minerals and other nutrients
through the gut wall - Actively synthesise nutrients such as K2, many of
the B vitamins and some amino acids - Help to chelate heavy metals from our system.
- Help to control parasites
- Fermenting unused energy
- Regulating the development of the gut
- Producing hormones to direct the host to store fats
- Repress microbial growth through the barrier effect
- Harmful yeasts and bacteria like Clostridium difficile
are unable to grow excessively due to competition
from the helpful gut flora
Why is Production of Short Chain Fatty Acids Important?
Fermentation of non-digestible substrates, supporting the growth of microbes that produce short chain fatty acids (SCFAs)
What is the most abundant SCFA?
Why is it so important? (3)
- Acetate
- Essential metabolite for the growth of other bacteria
- Used in cholesterol metabolism and lipogenesis
- May play a role in central appetite regulation
What is the Role of the SCFA Propionate?
- Transferred to the liver
- Regulates gluconeogenesis and satiety signalling
through interaction with the gut fatty acid receptors
What is the Role of the SCFA Butyrate? (3)
- Main energy source for human colonocytes
- Can induce apoptosis of colon cancer cells
- Essential for epithelial cells to consume large amounts
of oxygen through β oxidation, generating a state of
hypoxia that maintains oxygen balance in the gut,
preventing gut microbiota dysbiosis
The Role of the Gut Microbiota in Immunity
- Friendly bacteria occupy the majority of ecological
niches – outcompeting invasive organisms - Normal gut flora provides antigenic stimulation
- Lactobacilli in the stomach help to maintain acidic
conditions - Gut bacteria produce bacteriocins, including colicins
What are Bacteriocins?
Ribosomally synthesised antimicrobial peptides
with bacteriostatic or bacteriocidal effects against closely related bacterial strains
Effects Of Antibiotics on Gut Microbiome (4)
- Can alter the numbers of gut bacteria
- Can cause diarrhoea by irritating the bowel directly
- Allowing pathogenic bacteria to grow
- Creates antibiotic resistant bacteria in gut
What can reduced bacterial diversity in the gut or an
imbalance of the normal bacterial flora can lead to? (5)
- Infections
- Production of Toxins and Carcinogens
- Auto-immune Inflammatory Disorders
- Obesity
- Psychological Disorders
The Gut-Brain Axis
- Bi-directional communication between the central and
enteric nervous system - Neurotransmitters produced by enteric bacteria
regulate brain chemistry - Influences neuro-endocrine systems associated with
stress response, anxiety, and memory function
Why is it important to know that the enteric nervous system can affect brain chemistry?
Introduces possibility of probiotic supplements to improve outcomes for patients with anxiety, depression
and memory disorders
Excessive consumption of what has a negative effect on gut microbiota?
Sugars and sugar substitutes
Consumption on what can have a positive effect on gut microbiota? (3)
- Probiotic Supplements
- Dietary Fibre Intake
- Fermented Foods
