Micro of Animals Flashcards
commensals
microorganisms found on the bodies of healthy animals/people
- residents ( skin, mouth, colon)
- can do no harm, be beneficial or be parasitism
disease vs infection
disease= damage or injury to the host that impairs host function infection= situation in which microorganism is established and growing in a host, causing damage
pathogenicity
the ability of a parasite to inflict damage to host
virulence
measure of pathogenicity
opportunist pathogen
causes disease only in the absence of normal host resistance
phylogenetic studies suggest that herbivory has evolved _____ in many different lineages
independently
GIT of herbivores
live on plants – cellulose and other insoluble polysaccharides
- lack the enzyme cellulase
- microorganisms degrade cellulose and other fiber to give host nutrients (mutualism) in either hind or fore gut
2 digestive stragegies have evolved in herbivorous animals
- foregut fermentation: fermentation chamber precedes (comes before) the acidic stomach
- Hindgut fermentation: uses cecum and large intestine as fermentation chambers
foregut fermentors
ruminants, monkeys
- fermentation chamber before stomach
handgun fermetors
rabbits, horses
- fermentation chamber after the small intestine
the rumen of ruminant animals
rumen- foregut fermentation chamber in ruminant animals
food is chewed minimally, swallowed and passes to rumen
rumen condition in cows
100-150L
39-40 degrees
5-7 pH
anaerobic environment (fermentation)
how is pH in rumen maintained
by saliva which contains sodium bicarbonate
only a small proportion of the microorganism in the rumen produce ______. and as such fermentation is mediated by?
cellulases.
mediated by cellulytic microbes which break down cellulose into glucose and cellobiose (then available to all other microbes)
sugars in gut get fermented by microbes and produce?
volatile FA: acetic acid, propionic acid, butyric acid
methane and CO2
where do the FA pass and what are they used for?
through the rumen wall and into the bloodstream and used as the animals main energy source
overall stiochiomentry of rumen fermentation
57 glucose–> [65 acetate, 20 propionate, 15 butyrate] + 60 CO2, 35 CH4 and 25 H2O
which ones are the rumen microorganisms?
Ciliated protozoa, bacteria, archaea, methanogens (300-400 species)
Methanogens
strict anaerobes that produce methane from H and CO2 or acetate (CH3COOH)
acetate used by methanogens is not available to the ___
host
up to ___ % of energy value of the feed can be lost as CH4
10%
what compound is added to feed to reduce CH4 production
Monensin (inhibits methanogenesis)
explain what happens after several hours in the rumen
small portions are regurgitated, well chewed and then res wallowed. other portions get collected by the reticulum and moved to the omasum, where execs water is collected. then material goes to stomach (abomasum)
the mass of microbial cells that grow on the food are subjected to digestion, bc they then pass onto the small intestine and serve as a major source of ?
AA and vitamins
are tis the ones that were in the rumen?
what happens with non-ruminant herbivores
no rumen, so fermentation happens in the caecum
the microbial mass that grows on the cellulose are not digested, they are___-
excreted
what is the difference in ruminant herbivory and non-ruminant in terms of dietary requirements?
non-rum need more AA and vitamins —> bc microbial mass is not digested in non-rum
- rabbits get around this by eating their faecal matter
termites- anoxic environment in gut
decompose cellulose and hemicellulose
- have diverse anaerobic bacteria and celluloyti protists
Cefdinir
antibiotic to treat infection– produced int body?? after cow milk start in babies??
epimeric is composed of
living inner layer, dead outer c=layer
Sebaceous glands, apocrine sweat glands
secrete sweat and salt- secretion are slightly acidic and have antimicrobial properties
dead layer
prevents micro penetration
ducts that carry secretions are colonize by only a select few ___ species
gram - positive
normal microbiome secretes
bacteriocin
Actinobacteria
51 % gram-p on skin
teeth consist of
mineral (enamel) surrounding living tissue (dentin and pulp)
how do bacteria colonize tooth surfaces
attach to acidic glycoproteins deposited there by saliva
streptococcus mutans
lots of growth of microorganisms (especially streptococcus) result in dental plaque. In the presence of sugar, streptococcus mutant synthesize extracellular polysaccharides(dextran) that aid in the attachment to the tooth surface–> form an ECM (extracellular matrix)
as plaque begins to grow____ bacterial species grow
anaerobic
the various microorganisms plaque—> S. mutant and various lactobacilli- ferment sucrose and process
lactic acid that demineralizes the tooth enamel ( solubilizes calcium )
microorganisms in the human colon are mostly
strict anaerobes or facultative aerobes: bactericides, enteric bacteria, yeast, anaerobic protoza
methanogens are found in ___ of humans intestine tract
1/3
what are responsible for the smell in GIT
organosulfur compounds (methanethiol)
intestinal microorganisms benefit the host by producing
- ferment VFA –> produce gas CO2 and H2
AA, Vitamins B, K, thiamine riboflavin
obese mice had more ___
methanogens
- high H2 retards fermentation ( in lean mice)
- low H2 promotes fermentation in obese mice (more VFA and nutrients to host??) this is bad???
3 common in respiratory tract
streptococci, staohyoccocci and cornyebacteria
lower res track was once considered??
free of microorganisms
- now not the case, but still low biomass
genitourinary tract and urinary tract are generally free of microorganism due to flushing of
urine
Hormones control the ____ concentration of the vaginal epithelium
glycogen concentrations
microorganism degrade glycogen and produce ____
and produce lactic acid which reduces the pH of the vaginal tract tot 4.5
when are glycogen levels highest in the vaginal tract
sexually mature - acidic environment
main microbial flora that differs in sexual active female in the vaginal tract
lactobacilli—> make lactic acid – lowers pH
steril zones
blood, spinal fluid gut cavity (peritoneal cavity Pleural cavity sinuses interior region of body tissues
