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35 Cards in this Set
- Front
- Back
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How many times more bacterial cells are there in the gut than in the entire human body? |
10 times |
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How many bacteria are present in: 1. A healthy gut 2. The small intestine 3. The stomach 4. The Large intestine ? |
1. 10 ^ 14 2. 10 ^4 - 10 ^6 3. 10 ^ 3 4. 10 ^ 12 |
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How many bacteria species are present in a healthy gut? |
Over 3000 |
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What is a bacteriophage? |
A bacterial virus |
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What are the main bacterial species present in the gut? |
1. Firmicutes 2. Bacterioidetes 3. Proteobacteria 4. Actinobacteria |
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What are the two sides of the mutualistic symbiosis between humans and gut bacteria? |
1. Bacteria provide benefits to humans through absorbing vitamins and short chain fatty acids 2. Humans provide the microbiome wit a stable environment with a constant supply of food and water |
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When is developing the microbiota must important in a human life? |
During the first 3 years of life. |
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What types of children have a more healthy gut biome? |
Vaginally delivered chidren have a more diverse range of microbiota stemming from the contact with vaginal and fecal bacteria from the mother. |
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Why might humans be described as 'super organisms'? |
Metabolism of a human represents an amalgamation of microbial and human attributes |
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What are the beneficial effects of gut microbiota? |
1. Stimulation of host immune system 2. Aid digestion 3. Production of short chain fatty acids and vitamins 4. Inhibition of pathogenic bacteria 5. Transformation of bioactive compounds |
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What are the harmful effects of gut microbiota? |
1. Production of carcinogens 2. Play a role in obesity and diabetes 3. Involvement in inflammatory disease |
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How can we go about characterising the complex microbial communities in the gut? |
1. Isolate DNA i) sequence all the bacterial DNA ii) PCR the variable region of the genome's 16s RNA 2. Apply bioinformatics to inform from the mass of information |
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What bioinformatic techniques exist to help characterise the gut microbiota? |
1. Fluorescence in situ hybridisation 2. Gut microarray 3. Denaturing gradient gel electrophoresis 4. Cloning and Sequencing 5. Direct sequencing |
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What is the general name for DNA isolation of microbial communities? |
Metagenomics |
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What is the general name for mRNA of microbial communities? |
Metatranscriptomics |
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What is the general name for extraction of proteins from microbial communities? |
Metaproteomics |
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What is the general name for metabolite extraction from microbial communities? |
Metabolomics |
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What is ulcerative colitis? |
A form of Inflammatory Bowel Disease of the large intestine. |
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In ulcerative colitis; 1. Where do lesions occur? 2. What is the difference between bacteria in the ulcerative colitis and normal gut bacteria? |
1. Inflammation and lesions occur in intestinal regions with the highest bacterial concentration 2. The bacteria are very adherent |
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How are fecal samples of UC patients analysed? What does it reveal? |
1. a) Denaturing Gradient Gel Electrophoresis b) 454 pyrosequencing c) Partial Least Square analysis 2. Reveals far higher numbers of sulphate reducing bacteria |
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What is the point of a Partial Least Square analysis? |
A statistical test used to find the fundamental relations between two matrices |
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What are the key bacterial phyla in the gut? |
1. Firmicutes 2. Bacterioidetes |
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Name 2 key Fermicutes species present in the gut. |
2 from: a) Clostridium b) Ruminococcus c) Peptostreptococcus d) Lactobacillus e) Enterococcus |
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Name 2 key Bacteroidetes species present in the gut. |
2 from: a) Bacteroides b) Porphyromonas c) Preveotella |
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In obese mice what key difference in gut bacterial microbiota is observed? |
1. Obese mice have 50% fewer bacteroidetes than lean mice and far fewer Firmicutes |
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How was it deduced that gut microbiotal differences was a causative difference? |
When transfering caecal microbiota from obese mouse to a germ free mouse this resulted in a greater increase in total body fat when compared to another germ free mouse which had flora transfered from a lean mouse. |
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Production of what molecules is higher in the obese mouse? |
Increase in short chain Fatty Acid production. 1. Increase in Acetate production 2. Increase in Butyrate production |
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A Clostridium difficile infection is rare, why is this? |
Typically Clostridium difficile is competitively excluded from the gut microbiome |
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When does a Clostridium difficile infection typically occur? Why? |
When there has been a disruption of normal gut flora. Typically occurs after antibiotic treatment or in immuno comprimised patients. Following antibiotic treatment the normal gut flora are damaged by antibiotics - this allows C.difficile an opportunity to colonise, multiply and produce toxins = gut inflammation |
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Why is Clostridium difficile important to try and eradicate? |
C.difficile releases spores which persist in the gut and can lead to relapses later. |
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What possible treatments are there for Clostridium difficile? What are the advantages & disadvantages of each? |
1. Antibiotics However: Antibiotic resistance is a very dangerous risk which could be devastating 2. Bacteriotherapy Fecal transplant therapy to restore normal gut flora - appears to be very effective at preventing Clostridium difficile relapse however it is not a socially accepted therapy and donor screening must be extensive. |
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What factors affect gut bacterial composition? |
Host Factors i) Individual genotype ii) Ageing iii) Stress Dietary Factors i) Prebiotics / probiotics ii) Rich in fibre / iron Infection & Antibiotics i) Bacteria / viruses ii) Particularly broad spectrum antibiotics |
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The gut brain axis is a neuronal connection system which has been derived from studies on germ free mice. What kind of influences does the gut have on the brain function? |
1. Anxiety 2. Depression 3. Sensitivity to pain 4. Serotonin production 5. Autism |
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What are the main observations in germ free mice which resulted in creation of the gut brain axis model? |
1. Colonisation of germ free mice with microbiome of different types of mice showed that the recipient mouse would appear to take on the personality of the donor 2. Restraining mice in narrow tubes induces stress hormone production (HPA) in germ free mice treated with Bifidobacterium infantis the production of HPA is lower. |
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How many neurons does the gut brain axis have? What produces more serotonin; the gut brain axis or the brain? |
1. 100 million 2. The gut brain axis |
