Microbiology Chapters 6,20,28,30

Front 1

exponential growth

Back 1

with optimal growth conditions the number of cells in a culture increases exponentially.

Front 2

generation time

Back 2

time it takes for cells to double in a culture

Front 3

typical growth

Back 3

#cells(y) vs time(x)..
logarithmic=linear
arithmetic= exponential backwards "L"

Front 4

# of cell generations(N)

Back 4

N=N(t2)-N(t1)

Front 5

typical growth phases of batch cultures
(od=optical density, right hand side of graph from .1-1)

Back 5

lag:log=5,od=.1
exponential:log=5-8, od=.15-.65
stationary:log=8, od=.65
death:log=8-6.5, od=.65-.45

Front 6

continuous cultures (chemostat)

Back 6

growth rate is controlled by the rate of nutrient supply and the effluent of cells. The population is maintained in a steady state (#cells/ml doesn't change)

Front 7

relationship bw doubling time and dilution rate in a chemostat

Back 7

steady-state bacterial(y) vs
dilution rate(x) vs
doubling time(h) [right side]
doubling time=dec expon. "L"
bacterial []= rounded square
steady-state=leveled top of square

Front 8

water activity a(w)

Back 8

ratio of vapor pressure of the air in equilibrium of a solute in water/vapor pressure of pure water. varies from 1-0.

Front 9

water activity examples

Back 9

1 pure water spirillum
.995 human blood streptococ
.980 seawater vibrio
.750 salt lakes halococcus
.7 cereal,candy bisporus

Front 10

compatible solutes

Back 10

microorganisms grow in enviro's of low water activity they get water from increasing intracellular solutes by pumping is substance ions or synthesizing/acquiring organic compounds.

Front 11

major solutes accumulated

Back 11

glycine based for .97-.75
KCl for .75
glycerol .83-.61

Front 12

carbohydrate-type solutes

Back 12

sucrose: hex and pent

trehalose: two hex

Front 13

alchohol-type solutes

Back 13

glycerol:CH2OH-CHOH-CH2OH

mannitol:6C ends are CH2OH and middle 4 are CHOH

Front 14

amino acid-type and related solutes

Back 14

glycine betaine:5C, N-center with 3-CH3, 1-CH2 and 1-COO
ectoine:hex, 2N, 6C, 1 C=N
dimethylsulfoniopropionate:5C
1 C=O, 2 total O, and S

Front 15

growth indicators of oxygen[]

Back 15

resazurin:redox indicator is pink when oxidized(indicates location of O2)
low agar thioglycolate broth: reduces O2 to H2O

Front 16

growth responses to oxygen[]
obligate aerobe
oxygen sensitive aerobe
facultative aerobe

Back 16

obligate aerobe: no ferment
O2 sensitive aer: @ bottom
facultative aer:respires and ferments (dense top, sparse bottom)

Front 17

growth responses to oxygen []
microaerophile
aerotolerant anaerobe
oxic=top and anoxic=middle

Back 17

micro:grows at low O2 only, gives 2 section at top tube
aerotoler:ferments only, gives even particle spread

Front 18

anoxic jar and glove box

Back 18

rxn in bag generates H2 and CO2, palladium catalyst used to drive the rxn 2H2 + O2 gives 2 H2O molecules.
Airlock can be evacuated and filled with O2-free gas (N2)

Front 19

sterilization

Back 19

*process used to render a pdt or surface free of all viable organisms(spore/virus)
1.requires no damage to material during process or residue left that harms

Front 20

sterilization with....
antisepsis
disinfection

Back 20

anti:inhibition or destruction of microorganisms in or on living tissues(skin,linings)
disinfect:reduction of viable organisms on or in a pdt or surface to a level specified as being acceptable

Front 21

standardizing sterilization equipment and procedures....
effectiveness

Back 21

decimal reduction, killing 90% cells=1 decimal reduction
(ie: a 3-decimal reduction means a survival of 10e-3 or .1% of the initial # of cells or spores used to determine the effectiveness of a sterilization procedure.

Front 22

standardizing sterilization equipment and procedures

Back 22

with gram + use autoclaves

Front 23

decimal reduction times for the same mesophilic bacterium at different temperatures (log scaled)

Back 23

survival fraction(y) vs time
y-intercept=100 and corresponding graphs are linear decreases (for 50deg the decimal reduction time is 40 min, 60 deg=13 min, and 70 deg=4 min)

Front 24

comparison of the decimal reduction times at different temperatures for mesophile and thermophile

Back 24

decimal reduction(y) vs temp
thermophile: high linear dec
mesophile: low linear dec
(they are parallel)

Front 25

methods used for sterilization....
HEAT with pasteurization

Back 25

(wet heat,steam @ sub-atomospheric) used to reduce the # of living organisms(disinfection) in perishables

Front 26

methods used for sterilization....
HEAT with steam

Back 26

in autoclaves(wet heat, steam above atomos P) used to kill all organisms and spores to sterilize equipment and liquids that dont decompose is exposed to high heat.

Front 27

methods of sterilization...
HEAT with incineration

Back 27

used for the complete destruction of biological material(hazardous chemicals)

Front 28

methods of sterilization...
GASES

Back 28

such as ethylene oxide and ozone, used to sterilize heat sensitive materials, particularly plastics(petris,gloves) and lensed instruments. [ethylene is most common, its highly flammable and used when air isn't present]

Front 29

methods of sterilization...
RADIATION

Back 29

for materials that dont resist heat(plastic,veggies,meat,gel,pacemakers) UV has little penetrance and used to disinfect surfaces.

Front 30

radiation continued...
electron-magnetic radiation

Back 30

xrays:penetrate pduced by e- collision from heat cathode with heavy-metal anode
e:pduced in linear accelerations are very effective with low penetrance
g-rays:pduced by decay, very effective

Front 31

typical irradiation sterilizer

Back 31

typical exposure rack containing (60)CO as a generator of g-rays
(has shielded chamber, conveyor belt, ionizing radiation source(60)CO)

Front 32

radiation sensitivity of microorganisms and biological functions
(gram + ana and aero, gram - and gram +)

Back 32

gram + anaerobic....3300-2400
gram + aerobic......600
gram -..............200
gram +..............1200

Front 33

radiation sensitivity continued...
(gram - radiation resistant, mold, yeast virus)

Back 33

resistant...........2200
mold................500
yeast...............500
virus.............13,000-4500
(lethal human dose is 10Gy)

Front 34

methods of sterilization....
FILTERS

Back 34

membrane filters made from inert polymers(nylon,polycarbonate,nitrocellulose) sterilize chemical solns that dont resist heat. they dont reliably remove viruses.

Front 35

filtration apparatus in many sizes

Back 35

syringe:pre-sterilized disposable filter
lab continuous flow: pre-sterilized filtration unit
large in-line filter cartridge
industrial filtering unit

Front 36

methods of sterilization...
CHEMICAL DISINFECTANTS

Back 36

disinfect water supplies(chlorine,ozone,Cu-S), surfaces(bleach), medical and dental tools(H2O2) and disinfectants(iodine solns).
[a wide variety of all]

Front 37

water purification system
steps 1-3

Back 37

1.sedimentation: remove sand, large particles
2.coagulation:form and remove floc with insoluable material/microo
3.filtration:remove all remaining particles(ino&orgo)

Front 38

water purification systems
4-6

Back 38

4.chlorination:kill remaining microorganisms
5.storage:prevent growth of new inocula
6.distribution:finished water

Front 39

water treatment systems

Back 39

use a chlorine and a scale releasing agent

Front 40

infectious disease outbreaks associated with drinking water in the USA

Back 40

e.coli & jejuni....781
unknown............416
norwalk virus......356
salmonellosis......208
crptosporidiosis...5