Last ppt Flashcards
How dense is the population of the oral cavity microbiom?
Very densely populated
Does the entire mouth contain the same uniform type of microflora?
No, differeent regions are colonized by different types of bacteria
How much of the microflora in the oral cavity has not been established?
Half! Very complex
How is the skin’s microbiome distributed?
Thinly spread out over large surface area
What type of bacteria is skin microbiome dominated by?
Gram +
What part of the urinary tract is not sterile?
distal region of urethra
How is the vaginal microflora populated?
Densely
What is the predominant bacteria in vaginal microflora?
lactobacilli
What is the microflora of the upper respiratory tract like?
Complex
What is the composition of the uper respiratory tract’s microflora dependent on?
Anatomical site
How are the microflora of the lungs and internal tissues similar?
normally sterile
What 4 parts is the GI tract made up of?
Stomach, duodenum, jejunum, colon
What is the population density of the colon versus the stomach?
Stomach: sparcely populated
Colon: very densely populated
Which part of the human body contains most of the bacteria inhabiting humans? How much?
GI Tract
10^14
What are commensals?
Microorganisms normally found on healthy individuals
Do commensals cause infection?
No, commensals colonize the body without infecting it
How many microbes are on the skin?
10^12
How many microbes are in the mouth?
10^10
How many microbes are in the GI tract? What is the weight equivalent?
10^14
1 kg
Where are most of the GI tract’s microbes located? What %? Aerobic or anaerobic?
Colon
90%
Anaerobic
What 4 factors influence the richness and abundance of microorganisms on an individual?
- Temp
- pH
- Nutrient supply
- Immune system (genetic factor)
In what 3 ways can commensals be beneficial?
- provide host with vitamins and metabolic pathways (gut)
- Protect against new incoming microbial populations (guard their territory)
- Teach the immune system
Do all animals contain the same commensals?
No, commensals in one animal’s body may harm a different animal
Can commensals become parasitic/pathogenic?
Yes under specific conditions
What are pathogens?
Microbial parasites that are unable to cause infection
What is an infection?
A situation in which a microorganism is established and growing in a host, causing damage.
What is a disease?
Damage or injury to the host that impairs host function
What is pathogenicity?
ability of a parasite to inflict damage to the host
What is virulence?
measure of pathogenicity
What are opportunistic pathogens? Does the normal microbiom contain opportunistic pathogens?
Ones that cause disease only in the absence of normal host resistance.
yes
What are herbivores? Carnivores? Omnivores?
Animals that consume mostly plants.
Animals that consume mostly meat.
Animals that consume both.
What do phylogenetic studies suggest about herbivores?
Different lineages evolved a herbivorous lifestyle
What are two glucose residues next to one another in cellulose called?
Cellubiose
What do herbivores live off of? What are 4 of the insoluble polysaccharides that they eat?
Plant material rich in:
- Cellulose
- Lignin
- Hemicellulose
- Pectin
What enzyme do animals lack that plants have?
Cellulase
What two digestive strategies have evolved in herbivorous animals?
Foregut fermentation
Hindgut fermentation
What is the location of the fermentation chamber in foregut fermentation?
before the acidic stomach (in rumen?)
What does Hindgut fermentation use as fermentation chambers?
Cecum and/or large instestine
What are 4 examples of types of animals that are foregut fermenters?
Ruminants (cows), colobine monkeys, macropod marsupials, hoatzin
What are 4 examples of hindgut fermenters?
Cecal animals, primates, some rodents, some reptiles
What happens to food from the moment it enters a foregut fermenters mouth?
Chewed minimally, swallowed, and passed into the rumen
What is the volume of a cow’s rumen? A sheeps?
100-150L
6L
What is the temperature of the rumen? pH?
39-40 Celcius
5-7
Is the inside of the rumen aerobic or anaerobic?
Anaerobic
How is the pH of the rumen maintained?
Saliva which contains sodium bicarbonate and sodium phosphate
How much of the rumen’s microorganisms produce cellulase?
Only a small poriton
What is fermentation in the rumen mediated by?
Cellulolytic microbes
How do cellulolytic microbes break down cellulose?
They hydrolyze it into free glucose and cellobiose which is then available to all microorganisms for growth
What happens to the sugars (glucose) that the cellulolytic microbes broke down?
The sugars (glucose) are then fermented which produces volatile fatty acids, CH4 and CO2.
What are 3 examples of volatile fatty acids?
Acetic acid, propionic acid, butyric acid
How do the volatile fatty acids leave the rumen? What are they used as by the animal?
They pass through the rumen wall into the bloodstream. Used by the animal as main energy source
Rumen microorganisms contain how many microbes/g of rumen content?
10^10-10^11 microbes/g
What types of microorganisms inhabit the rumen?
ciliated protozoa, bacteria, archea