Micro Lab Final 2002

Ocular lens

Lens closest to the eye

Objective lens

Lens closest to the object

Condenser

Used to focus light on subject on microscope stage

Diaphragm

an iris used to control the aperture of light source

Resolution

The ability to distinguish to objects that are close together

Magnification

The apparent increase in size of an object from the power of the lens

Immersion oil

A substance with same refractive index as glass used to reduce reflection and refraction

Bibulous paper

A blotting paper used to dry sides

Lens Paper

A nonabrasive paper used to clean lenses

Smear

A histological technique used to disperse cells on a slide

Simple stain

Stain procedure with one dye used to determine shape, size, number and arrangement of cells

Differential Stain

Stain procedure that used multiple dyes and is used to distinguish cells and determine shape, size, number and arrangement as well.

Aseptic Technique

A combination of procedure that are used to reduce contamination, thus preventing sickness, infection or contaminated cultures.

Fixation

Technique used to attach cells to the slide and often kill and preserve

Positive stain

A stain that uses a basic dye and stains the cells leaving the background clear

Negative stain

A stain that use an acidic dye and stains the background dark leaving the cells clear or translucent.

Gram Negative Stain

A nonsense combination of terms that should be stricken from your vocabulary as is indicates a lack of understanding of the two totally different procedures.

Gram Stain

A differential stain used to differentiate gram + from Gram - based on the cell wall

Endospore

A specialized cell made by only a few types of bacteria that allow extended survival in harsh conditions

Endospore stain

A differential stain used to visualize endospores from vegetative bacteria

Vegetative

A term used in biology to describe non-reproductive tissue (or non-spore forming)

Decolorizer

A chemical mixture used to remove loosely bound dyes in a differential stain

Counterstain

A stain used to complement a primary stain in a differential staining procedure

Methanol

A simple alcohol that is converted to formaldehyde for fixing bacteria

Serial Dilution

A dilution series that is repeated to spread out bacteria for isolation or counting

CFU

Colony Forming Units

Colony Forming Units

A metric used for counting colonies when the actual number of bacteria seeded onto a plate is unknown.

Disk Diffusion

A assay used to determine the effectiveness of antimicrobial substances by measuring zones of inhibition.

Opportunistic Pathogen

A microbe that will cause disease if it has the opportunity such as a weakened immune system or high numbers

Infectious dose

The number of a particular microbe that is needed to initiate an infection

Minimum Inhibitory Concentration

The smallest amount of a substance that can prevent the growth of a microbe or kill them.

Viable

Alive or able to grow

Serial

related to a series of events

CFU

colony forming units

Dilution factor

The multiplication factor used to account for dilutions when counting microbes

Pure culture

A growth of microbe were there is only one species

Streak Plate

A technique that uses friction to isolate microbes on the surface of a Petri plate of agar medium

Spread Plate

A technique that uses a dilution to isolate microbes on the surface of a Petri plate of agar medium

Selection

A term used to describe when a condition is present that limits the growth of some organism and allow for the growth of others

Broad spectrum

kills or inhibits a large number of different kinds of microbes

Narrow spectrum

only kills or inhibits a few kinds of microbes

Resistance

ability to inactivate or grow in the presence of an antimicrobial substance

Sensitivity

where a microbe is inhibited or killed by an antimicrobial substance

Microevolution

Where accumulated mutations lead to a change in phenotype

Presumptive test

an assumption based on evidence

Positive control

Used to show your methodology works as it should

Negative control

used to show your results are from your experimental manipulation and not by accident.

Zone of inhibition

An area lacking visible growth that surrounds a bacterial colony or antibiotic disk indicating antibiotic production or sensitivity

Actinomycete

One of the main groups of antibiotic producing bacteria in the soil

Geosmins

One of the secondary metabolites produced by soil organisms that give it an "earthy" odor.

Challenge

To purposefully place two organisms in close proximity to determine if one inhibits the growth of another

Slurry

a semi-liquid mixture of a solid suspended in water, such as a slurry of soil

Decimal dilution

a serial dilution by factors of 10

Simmons Citrate Agar

medium used to determine whether an organism can utilize citrate as its sole carbon source

SIM medium

sulfur reduction, indole production, motility

MRVP broth

used to distinguish organisms that produce large amounts of acid from glucose and organisms that produce the neutral product acetoin/butanediol

Kovak's reagent

tryptophanase produces indole from tryptophan red is positive

streak plate

a technique for isolating pure cultures by spreading organisms on an agar plate

innoculating loop

simple tool used by microbiologists to retrieve an inoculum from a culture of microorganisms; transfer inoculum for streaking; has a loop on the end