microbiology lab

cytology

study of cells

histology

study of tissues

pathology

study of disease

magnification

apparent increase in image size

resolution

the ability to distinguish fine details

contrast

the ability to distinguish objects, such as cells, from the background; can be altered by light intensity and staining

microbiology

a field of biology that studies single and multicellular microscopic organisms

oil immersion

used only in 100x; a drop of immersion oil is added to the slide, contacting both sample and objective

factors that influence microbial growth

temperature, osmotic pressure, atmospheric gases, pH, mositure

ideal microbe environment

• temps 20-40 C

• moist conditions

• O2 rich environment

• close to neutral pH

agar plate

pour hot agar into petri dish and allow to cool; condensation common- store/label upside down

agar media

bacterial culture medium that contains agar as a solidifying agent and is used for growing microorganisms

agar slant

bacterial culture medium containing agar in a test tube that is allowed to solidify at an angle and forms a solid, slanted surface

aseptic technique

a set of procedures employed in the handling of microbes without causing contamination from outside sources

colony

a visible mass of microorganisms formed by replication of a single microorganisms on an agar surface, often in a petri dish

inoculating loop

a sterilizable tool made of wire, used to implant or move microorganisms

inoculum

a small amount of microorganisms used to start a new culture

liquid broth culture

a liquid nutrient medium used for the propagation of microorganisms

petri dish

a shallow, transparent glass or plastic dish that’s covered by a larger lid

pure culture

a bacterial culture containing only one strain of microorganism

sterile

an environment devoid of any living cells

40x and 100x

use fine adjustment on only?

maximize resolution

• blue filter- shorter wavelengths

• condensor- kept at highest position

• diaphragm- high for gram stain, low for motility

types of coccus

staphylococcus, streptococcus

types of bacillus

bacillus cereus, e coli

spiral

borrelia burgdorferi (lyme disease), treponema pallidum (syphilis)

nutrient agar

general purpose media supporting the growth of a wide range of microorganisms

culture tube

tube with bacteria culture

coccus

what bacteria shape is this?

bacillus

what bacteria shape is this?

spiral

what bacteria shape is this?

inoculating tools and mouth of glass culture tube

must be sterilized both before and after transfer by heating to red hot in the flame of a bunsen burner or in a micro-incinerator- let cool before picking up cells

smear prep

a technique used to produce a sample of microorgansims, typically for microscopy or staining

basics of smear preparation

• growing bacterial culture in liquid nutrient broth or agar plate

• acquire portion of sample for smear using aseptic technique

• apply sample to slide to distribute

• heat fixation of smear

• evaluation of quality of smear immediately using methylene blue

smear from solid media

1. two loopfuls of water are placed in center of slide

2. very small amount of solid culture dispersed with inoculating needle in water over middle 1/3 of slide

3. smear air dries at room temp

4. slide passed through flame for heat fixation

smear from liquid media

1. two loopfuls of liquid containing organisms placed in center of slide

2. culture dispersed over middle 1/3 of slide

3. smear air dries at room temp

4. slide passed through flame for heat fixation

bacterial cellular arrangement

description of overarching patterns and organization of bacterial cells seen across a microscopic field (ex: “clusters”, “in pairs”)

bacterial cell morphology

description of shapes and structure of bacterial cells seen across a microscopic field (ex: cocci, bacilli)

heat fixation

the process of applying gentle heat to a sample. fixing a specimen preserves various cellular components in a natural state with minimal distortion while simultaneously killing the specimen and securing it to the slide

methylene blue

a blue dye used to visualize cells in a bacteriological and biological staining (C6H18ClN3S)

microscopy

science that studies structure, magnification, lenses, and techniques related to use of a microscope

smear

an isolated and prepared sample of microorganisms for use in microscopy and staining

staining

a technique that utilizes dye(s) to add color for visualizing and distinguishing cells on a smear by increasing contrast