microbiology of animals Flashcards
the bodies of animals provide a –, —- and —– env for bacteria.
wet, warm nutritious
—- —- forces bacteria to colonize inside animal tissues
evolutionary presser
what factors influence the richness and the abundance of microorganisms in the body
temp, pH, nutrient supply, immune system (genetic factors)
as the animal develops, various body surfaces become progressively —-, the individual acquires its —- —-
colonized, normal microbiome
what are commensals
at firs most microorganisms may seem to be commensals. they take advantage of the host (nutrients, shelter) and they do not harm the host
in what ways can commensals be beneficial
1) AA supply
2) vitamin supply
3) metabolic pathways
4) protection against new incoming microbial populations (occupy the territory)
5) teach the immune system
(T/F)
commensals may also be parasitic
explain
true
some commensals may be pathogenic under specific conditions and commensals of one species may infect another species
in animals the vast majority of the microorganisms may be found in the —–
GI tract
phylogenetic studies suggest that different lineages evolved a —- life style
herbivorous
what are the challenges of herbivores
digestion is difficult for them due to the presence of cellulose and complex sugars (lignin, pectin, hemicellulose) in their diet –> also insoluble
animals lack the enzyme —-
cellulase
microorganisms in the gut have a —– relationship with the host. due to their ability to break down cellulose
mutualistic
name the 2 digestive strategies that have evolved in herbivores
1) foregut fermentation: fermentation chamber precedes acidic stomach
2) hindgut fermentation: use caecum and/or large intestine as fermentation chambers
rumen
foregut fermenation chamber
how is the pH of the fermentation chamber maintained + what is its pH
by the saliva - composed of sodium bicarbonate and sodium phosphate
5-7
rumen is an —- env
anaerobic
temp in the rumen
39-40 degrees
(T/F)
a large portion of the rumen contains cellulase
FALSE
fermentation in the rumen is mediated by —— that hydrolyze cellulose into —- and —– , then sugars are fermented into —— , — , —-
cellulolytic microbes, glucose , cellobiose, VFAs, CO2,CH4
what happens to VFAs after fermentation
thy pass through the rumen wall, enter the bloodstream and are utilized by the animal as its main nrg source
what kind of micro-organism exist in the rumen
ciliated protozoa, bacteria, archaea –> 16S
——- (microorganism) produce cellulase, and the product may be used by other microorganisms
ruminococcaeceae
methanogens are —
anaerobes