66 terms

Micr 221 Final Exam Study

The study of all the DNA sequenced from a community (eg of bacteria in gut)
Human Leukocyte antigen
Obligate aerobes and facultative anaerobes usually have which two enzymes for detoxifying ROSs
SOD and Catalase
Aerotolerant anaerobes have:
SOD and peroxidase
some obligate anaerobes have
The cardinal temps:
Min, Max and optimum
What bacteria go into when the temperature is too low for them
Protective dormancy
Effect on bacteria of too high temperatures
Thermal lysis
Mean generation time fastest at:
optimum temp
Lowest temp required to kill all cells in a standard suspension of bacteria in a liquid culture within a period of 10 mins
thermal death point
Length of time required to kill all cells in a standard suspension of bacteria in a liquid culture at a given temp
thermal death time
Length of time required to obtain a ten-fold reduction (1 log diff) in the numebr of bacteria in a standard suspension of bacteria in a liquid culture
decimal reduction time (d value)
can benefit from associations with humans but do not provide benefits for, nor harm, the host
nutrition, niche exclusion, & GI tract & Immune system functions boosted
benefits from mutualistic bacteria
parasitism vs pathogenesis
parasite cannot grow outside host
if given antibiotics, a commensal clostridium can rise up and cause:
ulcerative colitis
fungi & green algae/cyanobacteria. GA/C provide carbon for fungi, fungi provides water, minerals and substrate for GA/C to grow.
Another eg of mutualism, like lichen, but with a mammalian organ.
Bovine Rumen
E. coli using O2 in intestine andallowing only strict anaerobes to grow is an eg of what? (E. coli derives no obvious benefit from coexistance with anaerobes)
what % mass are bacteria and how many kg of them in our GI tract are there?
2.5, 2
Which 3 types of bacteria are usually found in our oral cavities?
Strep, Fuso, Actinomyces
Which 3 types of bacteria are usually in our upper resp. tract?
Strep, Staph, Neisseria meningitidis
Which 6 types of bacteria are usually in our GI Tract?
Lactobacillus, Bacteriodes, Bifidobacterium, Clostridium, Escherichia, Enterococcus
Type of bac usually an early coloniser of oral cavity?
Function of early colonisers
Secrete polysaccharides to make biofilm
Surface proteins on strep (ECs) help them:
stick to the biofilm
why is it an example of commensalism that the ECs make a biofilm?
LCs can't bind directly to teeth
Type of bac usually a late coloniser of oral cavity?
Fusobac bind to what?
surface proteins on ECs
Early in colonisation of OC, ph is
late in colonisation of OC, environment is
ECs are
facultative anaerobes
LCs are
obligate anaerobes
specific type of EC plaque bac
strep. mutans
s. mutans has 3 mechanisms of acid tolerance. What are the two things it exports?
Protons and lactic acid
the third thing strep. mutans has to increase its acid tolerance is:
Low membrane permeability to protons
Duodenum, Jejunum and Ileum make up the:
small intestine
Colon aka
Large intestine
does the colon (LI) have a presence or absence of oxygen?
site of continued digestion of monosacchs, AAs, fatty acids, water, with a pH of roughly 4-5
Small intestine
Helicobacter pylori attempts to maintain an intracellular pH of around 7 by making the enzyme ______ which converts urea to CO2 and _____ which reacts with protons to form ammonium ions.
urease, NH3
transporter of urea into H. pylori cells called
by which mechanism does NH4+ then exit the cell?
not known
GI microflora help make which 5 vitamins?
thiamine, riboflavin, B12, pyridoxine and k
GI microflora also increase this type of reaction to be carried out:
glycosidase reactions
human gut contains how many bacterial species?
classic approach to identifying bacteria in/on our body:
modern approach
DNA sequencing of 16S rRNA
Sequencing 16S rRNA allows which level identification of bacteria?
Gram positive bacterial phylum, eg clostridia, that inhabits the bowel
Gram negative bacterial phylum eg Bacillus fragilis that digest plant polysaccharides in the bowel
Gram negative bac phylum eg E. coli that synthesise vitamins in the bowel
Bac phylum in bowel eg bifidobacteria, that digest milk oligosaccharides and synthesise vitamins
The only archabacteria present in the bowel that consumes hydrogen gas in the gut, and produces methane
methanobrevibacter smithii
What percentage of bacteria found by a full metagenomic study were a) novel and b) not able to be cultured?
22, 83
against toxic compounds
bacteria are how many times more xenobiotic for us than we are ourselves?
when are humans and other mammals still sterile?
in utero
in human neonates the intestine is colonised primarily with which type of bacteria?
facultative anaerobes
during weaning, another type of bacteria takes over:
obligate anaerobes
main type and phylum of bacterium by adulthood
obligate anaerobes, bacteroides
the presence of this bacterial species increases intestinal surface area, development of blood vessels and therefore better digestion and absorption.
these symptoms were found in what?: higher susceptibility to infections, diminished cytokine levels, reduced serum immunoglobulin and CD4 T cell levels
gnotobiotic mice
a bacterial capsular polysaccharide antigen, causes expansion of splenic CD4 T cells, - what's it shortened to?
what's the benefit of aiding development of CD4 T cells for bacteroides?
longer colonisation period