Week2 lab

STAINING PROCEDURES

Various staining methods have been devised to enable scientist to examine bacteria.

Heat fixation

accomplished by passing the smear through a Bunsen burner flame

Methanol fixation

accomplished by flooding the smear with absolute methanol for 30 seconds

ACID FAST STAIN

procedure was developed in 1882 by Paul Ehrlich

Ziehl-Neelsen Method (Hot Method):

Heat: This method utilizes heat as a physical mordant to drive the

carbolfuchsin into the bacterial cell wall. The slide is gently heated during the

application of carbolfuchsin.

Kinyoun Method (Cold Method):

No Heat: This method does not involve heating. Instead,

it relies on a higher concentration of carbolfuchsin and a

longer contact time to achieve penetration.

MOTILITY

Swim

COLONY MORPHOLOGY

A single bacterial cell that lands on the surface of solid culture medium cannot be seen .

ATHMOSPHERIC REQUIREMENTS

Basis of their relationship to oxygen (O2)

And carbon dioxide (C02)

Obligate aerobes

Require an atmosphere containing molecular oxygen in concentration comparable to that found room 20% 22%

Microaerophiles

also require oxygen for multiplication but concentration about 5%

Obligate anaerobes

can only grow in an anaerobic environment containing oxygen

Aerotolerant anaerobe

Not required oxygen grown better in the absence of oxygen

Facultative anaerobe

Anywhere from 0 % 02 to 20% to 21% 02

Capnophiles

Presence of increased concentration of C02

Fastidious

Organisms with especially demanding nutritional requirements

BIOCHEMICAL AND METABOLISM

Waste product and secretion

GENETIC COMPOSITION

Test procedure deoxyribonucleic acid DNA or RNA

RICKETTSIAS

Obligate intercellular pathogens that cause disease in human and animals

CHLAMYDIA

Energy parasite

MYCOPLASMAS

Smallest of the cellular microbes

• lack cell wall they assume shape coccoid and filamentous