Pure culture: Isolation and characterization

Question 1

Culture that contains only ONE GROUP of microorganisms which is usually obtained when microorganisms in a culture medium are all of the same species

Answer 1

Pure culture

Question 2

relating to or denoting a culture that is free from living organisms other than the species required.

Answer 2

Axenic culture

Question 3

Instruments used to maintain pure culture (2)

Answer 3

Pipette

Inoculating needles and loops

Question 4

an instrument often used to transfer aliquots of culture, to
prepare serial dilutions of microorganisms, and to dispense chemical agents

Answer 4

Pipette

Question 5

used to aseptically transfer microorganisms from broth, slant, or agar cultures to other media

Answer 5

Inoculating needles and loops

Question 6

Pure Culture: Isolation and Characterization Requirements (3)

Answer 6

All apparatus must be sterilized

Desired bacterium must be separated from NATURALLY-OCCURING microbial population

Aseptic techniques used

Question 7

set of specific practices and procedures performed under carefully controlled conditions with the goal of minimizing contamination

Answer 7

Aseptic techniques

Question 8

Pure Culture Techniques (5)

Answer 8

Enrichment Culture

Single-cell isolation

Membrane filtration

Serial dilution

Plating

Question 9

ISOLATION of specific types of microorganisms by a combination of NUTRIENT and PHYSICAL conditions

Answer 9

Enrichment Culture

Question 10

uses micropipette or microprobe to physically pick a single cell and transfer it on an agar medium

Answer 10

Single-Cell Isolation

Question 11

Single-cell isolation steps (3)

Answer 11

Target

Suck and Hold

Discharge at intended position

Question 12

for samples with low population

Answer 12

Membrane Filter Technique

Question 13

used if the desired microorganism is present at a higher level
than any other microorganism

uses series of diluents to thin out microbial population

Answer 13

Serial Dilution

Question 14

Plating Techniques (3)

Answer 14

Streak plate method

Pour plate culture

Spread plate culture

Question 15

drop/s of culture placed on a slide and overlaid with a cover glass

observe true movement and morphology

Answer 15

Wet Mount Technique

Question 16

Pour plate method steps (4)

Answer 16

Inoculate empty plate (1.0 or 0.1 ml)

Add melted agar

Swirl to mix

Colonies grow in and on solidified medium

Question 17

Spread plate method (3)

Answer 17

Inoculate plate containing solid medium (0.1 ml)

Spread inoculum over surface evenly

Colonies grow only on surface medium

Question 18

3 or 4 quadrant methods (8)

Answer 18

Loop sterilized

Loop INOCULATED

First set of streaks

loop sterilized

Second set of streaks

Loop sterilized

Final set of streaks made

Isolated colonies develop

Question 19

measured by following changes in the number of cells or weight of cells

Answer 19

Measurement of Growth

Question 20

Direct methods of Measurement of growth (3)

Answer 20

Direct Microscopic count: Total cell count

Standard plate count (viable cell count) and serial dilution

Most probable number (MPN)

Question 21

Indirect Methods of Measurement of growth (3)

Answer 21

turbidity measurement

metabolic activity

total weight measurement

Question 22

Total cell count: Direct count (3)

Answer 22

Counting chamber method (Petroff-Hausser chamber)

Coulter counter method: automated electronic device

Breed count (direct microscopic count)

Question 23

counts the number of cells or units that are capable of forming a colony

Answer 23

Viable cell count

Question 24

Total cell count: Viable cell count (7)

Answer 24

Pour plate

Spread plate

Miles and Misra (Drop method)

Spiral plate method

Filtration

Roll tube method - for anaerobic microorganisms

Most Probable Number method (MPN)

Question 25

Slide used in Counting chamber method

Answer 25

Haemocytometer slide

Question 26

Counting chamber method (4)

Answer 26

Bacterial suspension added and fills shallow volume over squares by capillary action Volume calculated (depth x area) Microscopic count: all cells are counted and numbers are averaged Volume of fluid over the large square is 1/1,250,000 of a milliliter SO, if ther are 14 cells shown then there are 14 x 1,250,000 cells in a milliliter

Question 27

Also known as the ___ Particles are held in suspension in a DILUTE ELECTROLYTE which is drawn through the ORIFICE with a VOLTAGE applied across it VOLTAGE PULSE is recorded as particles flow through the orifice Amplitude of pulse can be related to volume of particle

Answer 27

Counter Counter method Electrozone Sensing method

Question 28

Breed count used in milk steps (6)

Answer 28

0.01 mL milk sample Spread out on 1 sq.cm area on glass slide, air dried Cover area with XYLOL for 1 min, air dry Flood with ALCOHOL for 1 min, drain, air dry Cover with METHYLENE BLUE for 3-5 minutes; wash with water Drain and dry without blotting, examine under oio

Question 29

measured subvolume of original sample material with which the sample is diluted

Answer 29

Aliquot Diluent

Question 30

Dilution (D): ratio of aliquot volume divided by the final volume Dilution (D) =

Answer 30

(volume transferred / total volume) x previous D

Question 31

Drops applied Applied in circular motion through a machine Surface of tube covered with GAS IMPERMEABLE STOPPER has agar

Answer 31

Miles and Misra method Spiral Plate Method Roll Tube Method

Question 32

Filtration method steps (5)

Answer 32

Membrane filter possessing millipores small enough to trap bacteria Water sample filtered through the filter to trap bacteria on the filter Membrane filter removed and placed in a petriplate filled with appropriate medium Petriplate incubated for 24 hours Typical colonies develop

Question 33

Measure of growth Other types (2)

Answer 33

Determination of Mass Measurement by Chemical Analysis

Question 34

Determination of mass (2) (2)

Answer 34

Direct - wet and dry weight Indirect - Turbidimetric methods - McFarland standards

Question 35

assay for specific biochemicals (proteins, nucleic acids) in microorganisms

Answer 35

Measurement by Chemical Analysis

Question 36

* more cells present, more light scattered, less light transmitted * ____ – detects amount of unscattered light * ____ is proportional to the number of cells but inversely proportional to the measurement that reaches the light detector

Answer 36

Turbidimetry Spectrophotometry optical density

Question 37

Used as basis of turbidity

Answer 37

McFarland Standard

Question 38

McFarland composed of?

Answer 38

Anhydrous BaCl2 H2SO4

Question 39

products of microbial growth is used to estimate number of organisms or confirm their presence

Answer 39

Metabolic Activity (cell products)