Cell Shapes

rods, cocci (spheres), spirals (spirochetes)

Most Bacteria are: 

unpigmented, and very difficult to see under microscope if they are unstained. 

Charge Bacteria have on their surface

NEGATIVE

Examples of positively charged stains: 

Safranin and crystal violet

SPORE FORMER: 

Bacillus Anthraces 

STEPS OF GRAM STAIN: 

ENDOSPORE STAIN: 

Bacterial endospores are metabolically inactive, highly resistant structures produced by some bacteria as a defensive strategy against unfavorable environmental conditions.  The bacteria can remain in this suspended state until conditions become favorable and they can germinate and return to their vegetativestate.  The primary stain applied is malachite green, which stains both vegetative cells and endospores.  Heat is applied to help the primary stain penetrate the endospore.    The cells are then decolorized with water, which removes the malachite green from the vegetative cell but not the endospore.  Safranin is then applied to counterstain any cells which have been decolorized.  At the end of the staining process, vegetative cells will be pink, and endospores will be dark green. (Note:  Endospore stains are performed on smears that have been heat-fixed.)  

GOALS OF ASEPTIC TECHNIQUE: 

1. prevent the culture from become contaminated by your or by the air.

2. to prevent YOU and everyone else from being contaminated 

PURE CULTURE: 

Streak Plate:

can be used to isolate bacteria regardless of the concentration of the cell

Pour and Spread plate

only achieve well-isolated colonies if the concentration of the cell is correct, so multiple dilutions must be made

What is the GASPAK SYSTEM? 

it creates an anaerobic environment within a sealed container by removing the oxygen chemically. 

Sugar Fermentation Broth

these tubes can determine if a particular sugar is fermented, as well as have a smaller inverted glass tube to determine if gas is produced as a waste product during fermentation. 

color change to yellow if sugar is fermented

SIMMONS CITRATE

agar turns from green to blue if citrate is utilized. 

MR-VP

sugar in broth is glucose, positive result for MR indicated that acid was produced as fermentation waste produce. 

VP test measures the production of acetoin as a waste produce. 

SIM test

CATALASE

catalase is an enzyme that breaks down hydrogen peroxide. Catalase test can be performed on any medium, but NOT on blood agar. 

good in determining GRAM POSITIVE COCCI

OXIDASE

colorless compound that turns dark blue in the presence of oxidase, which is part of the ETC

useful in gram negative rods

UREASE

COURSE OBJECTIVE KNOB SHOULD BE USED WHEN?

..with 10x. 

IMMERSION OIL MUST BE USED WITH..

100x

purpose of immersion oil: 

prevent light scattering, help light reach the bacteria. 

to remove primary stain during endospore: 

rinse with water. 

to isolate pure culture from a mixed culture, what is normally used? 

AGAR PLATE

what are facultative anaerobes?

they are able to grow anaerobically, but grow better with oxygen. 

Flocculent: 

visible chunks of materials in culture. 

SIM AGAR: 

identifies weather bacteria are producing hydrogen peroxide.