MHD1 Introduction

Question 1

What is the microbiota?

Answer 1

All microorganisms that live in a particular environment

Question 2

What is the difference between commensal, symbiotic and pathogenic microorganisms?

Answer 2

• does not affect other species
• has mutually beneficial relationship with other species
• disease causing

Question 3

What is the microbiome?

Answer 3

The entire collection of genes found in all of the microbes associated with a host

Question 4

What types of microorganisms does the microbiome include?

Answer 4

It includes bacteria, archaea, protists, fungi and viruses

Question 5

What can the microbial composition be altered by?

Answer 5

• Age
• Lifestyle
• Dietary habits
• Birth delivery modes
• Early-life feeding
• Exposure to pollutants
• Exercise
• Stress
• Infection and inflammation
• Xenobiotic and drug usage

Question 6

How many bacterial cells are there per human cell?

Answer 6

Now it is estimated to be 1.3 bacterial cells per human cells

Question 7

What essential functions do microbiota carry out?

Answer 7

• harvesting energy
• shaping the host immune system
• metabolism of xenobiotics
• metabolic signalling
• produce vitamins

Question 8

Give examples of microbiota derived metabolites

Answer 8

• Neurotransmitters – 5-hydroxindole and biogenic amines (dopamine)
• Short-chain fatty acids – products of fibre fermentation
• Branched chain amino acids – leucine, isoleucine, valine
• Phospholipids, triglycerides and fatty acids
• Bacterial choline degeneration products – trimethylamine-N-oxide (linked to CVD)
• Vitamins produced by microbiota – vitamin K
• Cometabolites of phenolics and aromatic acids

Question 9

How many virus and phage cells are there compared to bacterial cells?

Answer 9

Same number, or out number by an order of magnitude

Question 10

What part of the body has the greatest variety of microbes?

Answer 10

500-1000 species in intestine

Question 11

What part of the body has the least variety of microbes?

Answer 11

Stomach with 25 species

Question 12

Give examples of species are present on the skin? 1000

Answer 12

• Pityrosporum ovale
• Staphylococcus epidermis
• Staphylococcus haemolyticus
• Corynebacterium jeikeium
• Trichosporon

Question 13

Give examples of species present in the stomach 25

Answer 13

• Helicobacter pylori

* Streptococcus thermophilus

Question 14

Give examples of species present in the intestine 500-1000

Answer 14

• Lactobacillus casei
• Lactobacillus reuteri
• Lactobacillus gasseri
• Lactobacillus rhamnosus
• Escherichia coli
• Bacteroides fragilis
• Bacteroides thetaiotaomicron
• Clostridium difficile

Question 15

Give examples of species present in the urogenital tract 60

Answer 15

• Ureaplasma parvum

* Corynebacterium aurimocosum

Question 16

Give examples of species present in the Mouth, Pharynx, Respiratory tract 600+

Answer 16

• Streptococcus viridans
• Streptococcus salvarius
• Neisseria sicca
• Candida albicans

Question 17

Name 6 microbial communities on our body

Answer 17

Faecal, vaginal, skin, lung, oral, and gut microbial communities

Question 18

Babies born by C-section have an increased chance of what diseases?

Answer 18

asthma, allergies and obesity

Question 19

What does a new-born’s faecal microbiome community resemble to begin with?

Answer 19

vaginal

Question 20

After roughly two years what does the infant’s faecal community resemble?

Answer 20

An adults’ faecal community

Question 21

Antibiotic intervention under 6 months greatly increases chances of what disease?

Answer 21

Obesity (obesity can be determined to 90% accuracy just by observing gut microbes)

Question 22

Why/How do gut microbes influence weight?

Answer 22

Because of greater efficiency in digestion of food producing more energy, or an increase in food consumption (alteration of behaviour.)

Question 23

What is one quickly developing way to treat C.diff infections?

Answer 23

faecal transplants: A faecal transplant from a healthy donor can reverse the diarrhoea after just a day and can keep the patients with a healthy faecal microbial community.