Microbiology Lab Exam 2

Front 1

capsule stain

Back 1

the technique begins as a negative stain; cells are spread in a film with an acidic stain and are not heat-fixed.

heat fixing causes the cell to shrink, leaving an artifactual white halo around them that might be interpreted as a capsule.

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capsule stain

Back 2

a differential stain used to detectc ells capable f producing an extrecellular capsule.

capsule production increase virulence in some microbes by making them less vulnerable to phagocytosis

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capsule stain

Back 3

the acidic stain colorizes the background while the basic stain colorizes the cell, leaving the capsules as unstained white clearings around the cells.

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capsule stain procedure

Back 4

1. begin with a drop of serum at one end of a clean slide. add a drop of congo red stain.

2. add organisms with a loop. do not over-inoculate and avoid spattering the mixture.

3. clean up the slide with another slide

4. air dry DO NOT HEAT FIX

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endospore stain

Back 5

a dormant form of bacterium tat allows it so survive poor enviornmental conditions. Spores are resistant to heat and chemicals because of a tough outer covering made of the protein keratin.

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keratin

Back 6

resists staining, so extreme measures must be taken to stain the spore.

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Schaeffer- Fulton

Back 7

method of a primary stain of malachite green is forced into the spore by steaming the bacterial emulsion.

Front 8

malachite green

Back 8

water-soluble and has a low affinity for cellular material, so vegetative cells and spore mother cells can be decolorized with water and counterstained with safranin.

Front 9

endospore

Back 9

spores can be locate in the middle of the cell (central), at the end of the cell( terminal) , or between the end and middle of the cell ( subterminal)

Front 10

endospore shape

Back 10

spherical- sphere (circular)

elliptical (oval)

Front 11

the schaeffer sulton spore stain

Back 11

Front 12

schaeffer sulton spore stain

Back 12

Front 13

application of schaeffer sulton spore stain

Back 13

Front 14

wet mount and hanging drop preparations

Back 14

Front 15

brownian motion

Back 15

collisions with water molecules

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application

Back 16

simple wet mounts and the hanging drop technique allow observation of living cells to determine motility. they also used to see natural cell size, arrangment, and shape.

Front 17

hanging drop preparation precedure

Back 17

Front 18

flagella stain

Back 18

Front 19

monotrichous

Back 19

having a single flagellum at one pole

Front 20

flagella arrangments

Back 20

Monotrichous= 1 flagella
Lophotrichous= multiple flagella in the same area
Amphitrichous= 2 flagella; the flagella are on opposite ends of the cell
Peritrichous= multiple flagella pointing in many directions/located at many spots on the cell.

Front 21

polar flagella

Back 21

Front 22

amphitrichous flagella

Back 22

Front 23

lophotrichous flagella

Back 23

Front 24

peritrichous flagella

Back 24

Front 25

procedure

Back 25

1.prepare a wet mount

place a drop of water on the slide

place loop on growth and dont move it

allow bacteria to swim for 30 seconds

remove the loop and place it in the drop of water on the slide, again allowing the bacteria to swim for 30 seconds.

gently put a cover slip

2.observe the specimen under high dry power and not any motility. if there is motility continue the procedure. If it is not observe the brownian motion and then prepare a wet mount of a different organism

3. if it is motile let the slid dry for 10-15 minutes

4.leave the slide on the microscope stage and apply the RYU stain to the edgeof the coverslip using a syringe.

Front 26

streak plate methods of isolation

Back 26

Front 27

mixed culture

Back 27

two or more species

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pure culture

Back 28

only single species

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isolation technique

Back 29

streak plate

Front 30

streak plate method

Back 30

several patterns are used in streaking and agar plate, the choice of which depends on the source of inoculum and microbiologists preference. they range from simple to more complex, all are designed to seperate cdeposited cells (CFU's) on the agar surface so individual cells (CFU'S) grow into isolated colonies.

Front 31

quadrant streak

Back 31

used with samples suspected of high cell density

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zigzag pattern

Back 32

may be used for samples containing lower cell densities.

Front 33

patterns for streaks

Back 33

Front 34

evaluation of media

Back 34

composed of compunds from four biochemical families

- proteins

-carbohydrates

-lipids

-nucleic acids

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auotrophs

Back 35

require the least "assistance" from the enviornment to grow

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heterotrophs

Back 36

required preformed organic compounds from the enviornment

some are metabotically flexible and require only a few simple organic compounds from which to make all their biochemicals. others require greater portions of their organic compounds from the enviornment

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fastidious

Back 37

an organism that relies heavily on the environment to supple ready- made organic compounds.

Front 38

evaluation of media

Back 38

the more fastidios the organism, the more ingredients a medium must have.

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undefined media

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complex media, are composed of extracts from plants or animal sources and are rich in nutrients. they are useful in growing the greatest variety of culturable microbes.

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defined medium

Back 40

chemically defined medium, the mount and identity of every ingredient is known. typically supports a narrower range of organisms.

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procedure

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Front 42

the effect of temperature growth

Back 42

habitats ranging from -10 degress celsius to more that 110 degrees C

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cardinal temperatures

Back 43

temperatures characterized as minimum, maximum, optimal

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optimum temperature

Back 44

temp at which an organism shows the greatest growth over time- its highest growth rate.

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psychrophiles

Back 45

organisms that grow only below 20 degress

common in ocean, artic and anartic where temp. is permanetly cold

no fluctuation

Front 46

psychrotrophs

Back 46

0-30

Front 47

mesophiles

Back 47

bacteria adapted to temperatures between 15 degrees and 45 degrees celsius

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thermophiles

Back 48

organisms adapted to temperatures about 40

typically found in organic material and in hot springs

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obligate thermophiles

Back 49

DO NOT grow under 40

Front 50

faculatative thermophiles

Back 50

CAN GROW UNDER 40

Front 51

extreme thermophiles

Back 51

65-110 and best at 80

Front 52

graphs for temp

Back 52

Front 53

antimicrobial susceptibility test

antibiotics

Back 53

natural antimicrobial agents produced by microorganisms. ex- penicillin notatum

Front 54

kirby-bauer test

Back 54

also called the diffusion test, is a valuable standard tool for measuring the effectiveness of antimicrobics against pathogenic microorganisms. as the drug moves through the agar, it establishes a concentration gradient. if organisms is suspectible to it, a clear zone will appear around the disk where the growth has been inhibited.

Front 55

zone of inhibition

Back 55

the size depends upon the sensitivity of the bacteria to the specific antimicrobial agent and the point at which the chemical's minimum inhibitory concentration ( MIC) is reached. some drugs kill the organism and are said to be bactericidal.

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bacteriostatic;

Back 56

they stop growth but dont kill the microbe.

Front 57

muellar hinton agar

Back 57

has a pH 7.2-7.4

the depth poured into the petri dishes is important because of its effect upon the diffusion.

Front 58

thick agar

Back 58

slows lateral diffusion and thus produces smaller zones than plates held to the 4mm standard.

Front 59

antibitotic targets and resistance mechanisms

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antimicrobials used

1. penicillin
2, chloramphenicol
3. trimethoprim
4. ciproflaxin

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bacterial strains

Back 60

1. escherichia coli
2. staphylococcus aureus
3. pseudamonas aeruginosa

Front 61

Mueller-Hinton agar & bacterial inoculation

Back 61

1. inoculation is made w/a broth culture diluted to match 0.5 McFarland turbidity standard
a. standard contains barium sulfate to produce turbidity

Front 62

Mueller-Hinton agar & antimicrobial diffusion

Back 62

1. If agar is too thick, agar slows lateral diffusion and produces smaller zones than in 4mm agar plates

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antimicrobial susceptibility testing

Back 63

1. used to measure effectiveness of antibiotics and other chemotherapeutic agents on pathogenic microorganisms
2. a tool in prescribing the appropriate treatment

Front 64

standard plate count

Front 65

original sample value

Back 65

density and volume from the OCD = CFU / (D x V)

it becomes OCD = CFU / original sample volume

Front 66

Formula for calculating original cell density (OCD)

Back 66

OCD = CFU / (D x V)

D is the dilution as written on the dilution tube from which the inoculum comes.

V is the volume transferred to the plate.