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High temperature effect on microbial growth
microbicidal
denature enzyme
Destroy lipids that make up membrane
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Low temp effect on microbial growth
microbistatic
slow growth of cell,
reducing rate of chemical reaction
Reducing fluidity of cell membrane
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Cardinal temperature
Min optimum and max temp for particular bacteria species
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Psychrophile
-5C to 20C
cold arctic
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Psychrotroph
0C to 35C (below optimum temp)
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Mesophile
10C-50C
better at 20-40
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thermophile
45C-80C hot
composting organic material/ hot springs~
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Hyperthermophile
>70C
extremee thermophile
archaea
very hot
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Thermus aquaticus obligate thermophile
hot water
70C thrive
50C below die
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High temp denature enzyme
true
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high temp destroy lipid
T
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mesophilic able to grow at 4 C
psychrotroph
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Min, optimum and max of S marcescens
5, 37, 40
Red = prodigiosin at 25C
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Min, optimum and max of E coli
4, 37, 45
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Min, optimum and max of G stearothermophilus
40, 50, 80
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How to calculate absorbance on spectrophotometer
A=2-log(%T)
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PH formula
pH = -log 10[H+]
0 to 14 below 7 is acidic
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Water PH and H ions
10^-7 moles/L of hydrogen ion
PH 7
neutral
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change in one PH represent
10 fold increasing or decreasing in hydrogen ion
PH 8 is 10 times more basic than PH 7
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bacteria keep internal PH near__ regardless of outside
neutral
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bacteria keep internal PH near__ regardless of outside cuz __ are easily damaged by PH
neutral, enzyme
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if enzyme can't counter outside PH
denature
limit atp production
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__ added to media to stabilize ph
buffer
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V. parahaemolyticus (gastroenteritis) is a .... and grows in what temp
mesophile grow in 16C
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as concentration of hydrogen ion increases, PH
decreases, more acidic
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PH scale what is basic and acidic
0-14
below 7 acidic
above 7 basic
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Neutrophil favor PH
5.5-8.5
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acidophile favor ph
below 5.5
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alkaliphile favor ph
above 8.5
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how many more acidic is ph 7 than ph 9
100X
each change in PH is 10 X
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Growth of Ecoli, A. faecalis, and T. keyfir under 5, 7, 9 PH
Ecoli optimum growth is 7
A. faecalis optimum growth 9
T keyfir optimum growth is 5 then drops
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What environment does clostridium botulinum endospore like?
anaerobic ph higher than 4.6
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most abundant component of cytoplasm
water!
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Water act as a ____for chemical reaction and serve as a source of ___
solvent, hydrogen ion
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How water travels
down their concentration gradient
low solute to high solute
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Osmosis
diffuction of water across cell membrane
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Pressure created by flow of water into cell
osmotic pressure
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usually inside of cell has ___ concentration of solute than outside, so water
higher, rush in
aka hypotonic
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Hypotonic
high solute inside cell
increase osmotic pressure
water flow in
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What stops cells from lysing due to water pressure
cell wall
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isotonic
solute outside is same as inside
water cross equally, no net movement
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hypertonic, water flow__, what happens to cell
solute outside is greater
water go out
plasmolysis, flat
irreversible damage to enzyme
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majority of bacteria grow best at salt level
0.9% to 1.0%
aka inside me!
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Ecoli, S aureus, H salinarium in 0.5%, 5%, 10% and 25% Nacl
E coli- grow only 0.5 and 5% salt
S. aureus grow on 0.5, 5, 10% salt
H salinarium grow only on 25% salt
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Solute vs solvent
solute- dispersed in solvent
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Ham is 6% nacl, what bacteria is expected?
S. aureus, falculative halophile
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Vibrio vulnificus
consumption/ contact with opem wound of uncooked shellfish
brackish water low salinity and warm
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Gamma rays and X ray length
short wavelength <0.00001-100 nm
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ultra violet wavelength UV-A, UV-B, UV-C
100-380 nm long
UV-A 315-400nm
UV-B 280-315nm
UV-C 100-280 nm 254nm*
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Electromagnetic radiation works by
interacting with DNAand breaking down water to form highly reactive free radical
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Exposure of UV-C result in, most effective wavelength is
pyrimidine dimers, 254nm
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pyrimidine dimers,
254nm
covalent bond
T-C, C-C, T-T
distort DNA , death
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Growth of B megaterium and S aureus after UV
B megaterium still some after 45 min
S. aureus no growth after 10 min
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cryptosporidium parvum
resistant to chlorine but not UV light
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Normal microbiota of skin can be divided into
Diphtheroids
Staphylococci
Yeast and fungi
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Diphtheroids of normal microbiota
propionibacterium acnes
anaerobic bacteria- on hair follicle that break oily secretion
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staphylococci of normal microbiota
non pathogenic
beneficial- compete and fight with pathogen for nutrients
ex. S.aureus
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Yeast and fungi of normal microbiota
non pathogenic, digest oily emission of secretory gland
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Transient bacteria
temporarily, depends on hygiene
varied in form: gram - and +, rod, cocci, spore, vegetative
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Handwashing dilution factor
Average similar # X
1/volume = dilution factor
=organism/ml
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Optimum hand washing time for surgery
7 min
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Antibiotics
chemical substance from microorganism that can inhibit or kill another microbe even in a minute amount
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overuse of antimicrobics has led to
resistant strain of bacteria that are immune to substances
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susceptibility testing and 2 goals
identify effective chemotherapeutic agent
kill only pathogen and leaving other alone
appropriate therapeutic dose
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selective toxicity
kill only pathogen while leaving other unaffected
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disc diffusion
bacteria is spread on the plate discs of antimicrobics
high level near disc
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Zone of inhibition is dependent on
molecular weight of antimicrobic, type of medium, concentration of bacteria culture
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Kirby- bauer standard
medium: Mueller Hinton II 4 mm
bacteria culture 0.5 Mcfarland standard turbidity
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Sensitive and resistant zone of inhibition
sensitive= large zone of inhibition, good drug
resistant= small zone, bacteria is resistant to drug
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what information is not provided by the Kirby-Bauer test and know two ways could be obtained.
MIC- minimal inhibitory concentration(lowest level of chemical that inhibit drug
Tube dilution- single antimicrobic drug
Etest- read where inhibition ellipse intersects scale
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What do many bacterial strain now require to identify effective chemotherapeutic agent
susceptibility testing
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klebsiella
carbepenem-resistant enterobacteriaceae
wide rage antibiotic resistance
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how to calculate therapeutic index
toxic does/MIC minimal inhibitory concentration
low is good
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Who tracks data related to infectious disease
Center for disease control and prevention CDC
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Notifiable disease and where to find this info
76 serious disease docs need to tell CDC
Morbidity and Mortality weekly report MMWR
online: National notifiable disease weekly tables
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Morbidity
# cases per period/ susceptible population at mid point X K
whole #
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Mortality:
# disease related deaths per period/# people with the disease
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Incidence
# new cases/ at risk population at mid point
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3 common epidemiological measurement
morbidity, mortality, incidence
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Genotype & Phenotype-
Genotype- combination of genes it possess
Phenotype- appearance. Ability to utilize lactose, produce cell wall, withstand drugs
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Conjugation-
DNA transferred from one bacteria to another through pilus
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Transduction-
bacteriophage transfer small DNA from lysed bacteria to another of same species
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Transformation
bacteria receive small amount of DNA from environment
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four areas of interest in a typical plasmid what each of these areas does.
Origin of replication- sequence of DNA that is recognized by enzyme and ensure plasmid will be replicated
Drug resistance- usually ampicillin, ensure cell with plasmid will survive in antibiotic containing medium
Gene of interest- gene to be expressed, vary depending on transformation
Promotor- genetic switch allowing gene to be transcribed
Constitutive promoter- gene is transcribed at all times
Inducible promote allows gene to be transcribed only when specific condition(nutrient) exist
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important aspects of the transformation process
Green fluorescent protein(GFP)- fluoresces under UV light. Used to determined if transformed gene is being transcribed
Plasmid (pGLO)- vector to intoduce GFP gene in Ecoli
DNA binding protein (AraC)- regulates arabinose promotor./ transcription. If arabinose not present, this prevent RNA polymerase from binding to arabinose promotor
B-lactamase gene(bla)- hydrolyze B lactam antibiotics (ampicillin)
Origin of replicaiton(ORI) allow plasmid to be recognized and replicated by DNA polymerase within cell
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arabinose operon
When arabinose is in environment, it binds to ARAaC and allows RNA polymerase to mind to promotor and transcribe GFP producing MRNA that produces green protein
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Origin of replication on plasmid
sequence of DNA that is recognized by enzyme and ensure plasmid will be replicated
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Drug resistance- on plasmid
usually ampicillin, ensure cell with plasmid will survive in antibiotic containing medium
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Gene of interest- on plasmid
gene to be expressed, vary depending on transformation
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Promotor on plasmid, 2 kinds
genetic switch allowing gene to be transcribed
Constitutive promotor- gene transcribed at all times
inducible promotor- gene to be transcribed only when specific condition exise
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Transcription of GFP gene is controlled by
when arabinose is in environment, arabinose promotor allows it to bind to AraC which allows RNA polymerase to bind to promotor and transcribe GFP creating mRNA
bla = resistance to ampicilllin
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increase efficiency of transcription
making cell competent - treat it with Calcium
neutralize neg charge
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Transformation efficiency
# colonies/
volume DNA * concentration DNA*fraction on plate
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-troph and obligate
troph: grows across wide temp range
obligate: stick to specific temp
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halophile
grow in high salt environment
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halotolerant
can withstand high salt without adverse effects
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-phile
love
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osmophile
grow in high sugar concentration
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resident microbiota
deep stable microbiota
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penicillin
naturally occuring and synthetic antibiotics produced by penicillium mold and active against bacteria
