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62 Cards in this Set

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orderly arrangement of sets of organisms into a system
classification
recognition of an unknown organism and placing it in a set of the scheme
identification
this method of classifying bacteria refers to the mole % G + C
DNA composition
the dna composition of Clostridium tetani vs. mycobacterium tuberculosis
clostridium tetani 30%
mycobacterium tuberculosis 7-%
the procedure of DNA-DNA hybridization
way of classifying bacteria by "DNA sequence"
isolate DNA, cut it up, mix it with known DNA, heat it to separate strands, cool to reanneal, rinse away fragments, record radioactivity
short fragment of DNA that is specific for a particular gene
probe
the biological analog to serological typing
phage typing
life cycle of a phage
phage binds to surface receptors
phage injects its DNA into bacterial cell
DNA is transcribed and many phages are made in the cell
these lyse the cell and release phage to infect other cells
why are phages good antibiotics
there is no antibiotic resistance, humans have no surface receptors
this biochemical test determines if an unknown organism is S. aureus or S epidermidis (+) OR streptococcus (-)
catalase test
after a positive catalase test, this can decide between S aureus (+) or S epidermidis (-)
coagulative test
process in which bacteria multiply by cell division
binary fission
enlargement in cell wall where division starts
wall band
inward extension of wall band where cell division will occur
nascent septum
in binary fission, the wall band splits into two and is known as the
wall notch
in binary fission these enzymes open the backbone and allow entry of wall subunit
murein hydrolases
binary fission without cell separation can lead to these two
streptococcus
staphylococcus
complex of proteins involved in cel division
divisome
chief protein of divisome that recruits other proteins, which bring down the membrane and stimulate septum formation
FtsZ
two types of cells are slowly and rapidly dividing cells
slowly - finish replication before cell division is started
rapidly - multiple replication forks, physiologically significan in terms of gene dosage, each one expressing its product changes physiology of cell
growth rate of gram negative rod cell division
20-30 minutes
growth rate of gram positive cocci cell division
45-60 minutes
growth rate of acid fast bacteria
up to 24 hours
4 ways of measuring cell growth that do not separate viable from nonviable cells
packed cell volume - centrifuge and mass the pellet
spectrophotometry - measure optical density of culture by passing light through it
measure some component of cell like protein, DNA, ATP
microscopy - count cells
only way to measure viable counts of cell growth
viable counts - prepare serial dilution until you get small amount of cells, put that on a plate and incubate it, then count colonies and multiply back
what determines length of LAG phase?
1. if cell was just in stationary phase it is depleted and needs more time to uptake nutrients
2. composition of medium
3. organism itself, if it has efficient uptake system
experiment with low glucose and excess lactose
diauxie
cell heaven; new medium added with a spout, keeps bacterial cells continuously in log phase
chemostat
entire bacterial cell in same phase of growth
synchronous growth
way of getting synchronous growth where culture passed through filter paper and then turned over, allowing cells to grow and fall onto filter paper
age: membrane elution
way of getting synchronous growth where culture passed through stay of filter papers, only small cells get through
size: filtration
way of getting synchronous growth where culture put 37 degrees then back to 25 degrees so cold sensitive enzymes shut down temorarily
temperature
way of getting synchronous growth by interfering with DNA replication
thy-mutant - remove thymine, then put it back in. cell replication depends on thymine being present
infection of bacteria when all normal flora is killed and the only thing left is antibiotic resistant bacteria
enterocolitis
infection in vaginal tract, isnt a problem unless normal flora wiped out
candida infection
penicillin only affects these cells
growing cells
gram negative cells take this long to kill
seven days
gram positive cells take this long to kill
ten days
acid fast organisms take this long to kill
one year - tuberculosis
flat, thick growth of bacteria on cell surface
biofilm
bacterial cells in biofilm enclosed in this
exopolysaccharide
refers to gene expression that is a function of number of cells present
quorum sensing
twitching motility done by:
type IV pili
how does biofilm get nutrients
by diffusion through channels exposed to the outside
this enzyme digests exopolysaccharide
exopolysaccharide ligase
growth of flagella and its synthesis
planktonic growth
single cells which may float or swim in a liquid medium
planktonic cells
how many genes are turned on or off when going from planktonic growth to biofilm growth
800
are cells in biofilm stage growing?
no, they are dormant
why are biofilms resistant to antibiotics?
thickness, could be polysaccharide itself that neutralizes antibiotics, could be antibiotic influx pump - cells come in put are pumped out too quickly, or could be cells are dormant so antibiotics don't act
why are biofilm cells phagocyte resistant?
thickness makes them inaccessible
what is different about DNA in cells in biofilm?
cells can exchange DNA between each other because they are close
what is the quorum sensor in gram negative
acyl homoserine lactone
what is the quorum sensor in gram positive
small peptide
is quorum sensing a property of the individual or the group
the group because one induces others to release more sensors
release of planktonic cells from biofilm
swarming
how can biofilm move from one area to another
a clump can break off and roll somewhere new
rippling - entire biofilm moves
clumping - can get into blood and form a clot
medical issues with where biofilm can form
dental plaque, catheters, artificial joints, heart valves
why is cystic fibrosis so bad
the thick mucous is a basis for forming biofilm that causes chronic lung infections and is antibiotic resistant
what are biofilms like multicellular organisms
its a conglomeration of cells of different species that communicate and have different roels
adding bacteria via ingestion for specific purposes
probiotics
when you take nonliving food additive for purpose of stimulating the growth of particular organisms
prebiotics