IMVIC Tests and Microbial Biochemistry

Flashcards containing vocabulary terms and definitions related to IMVIC tests and microbial biochemistry.

IMViC Tests

A set of tests (Indole, Methyl Red, Voges-Proskauer, and Citrate) used to differentiate members of the Enterobacteriaceae family.

Enterobacteriaceae

A family of Gram-negative, bacilli, facultative anaerobes, and glucose fermenters.

Coliforms

Enteric bacteria that ferment lactose, includes Escherichia coli and Enterobacter aerogenes.

SIM Test

A test for Sulfur, Indole, and Motility; detects hydrogen sulfide production, indole production, and bacterial motility.

Cysteine desulfurase

An enzyme that hydrolyzes cysteine to generate H2S and pyruvate.

Thiosulfate reductase

An enzyme that reduces thiosulfate to hydrogen sulfide (H2S) in anaerobic respiration.

Indole production

A process where tryptophan is hydrolyzed to indole and other products by bacteria with tryptophanase.

Kovac's reagent

A reagent used to detect indole by producing a red ring, indicating the presence of indole.

Motility

The ability of bacteria to move, detectable by growth patterns in semisolid media.

TTC

Triphenyltetrazolium chloride, a dye used in motility tests; turns red when reduced by active bacteria.

MR-VP medium

A medium containing glucose and a buffer used to differentiate organisms based on fermentation patterns.

Methyl Red Test

A test that indicates acid production from glucose fermentation; involves pH indicator Methyl Red.

Voges-Proskauer Test

A test that identifies organisms capable of producing neutral fermentation products like acetoin.

Red ring (in Indole test)

Indicates a positive result for the presence of indole when Kovac's reagent is added.

Black precipitate (in SIM test)

Indicates hydrogen sulfide production by reacting with iron in the medium.

Acidic products (in MR test)

Products like lactic acid and acetic acid produced by organisms capable of mixed acid fermentation.

Neutral products (in VP test)

Products like 2,3-butanediol and acetoin produced by organisms fermenting glucose neutrally.

Bromothymol blue

A pH indicator used in citrate utilization tests; changes color based on pH.

Citrate permease

An enzyme that allows the transport of citrate into cells, crucial for citrate metabolism.

H2S

Hydrogen sulfide, a gas produced during anaerobic fermentation by certain bacteria.

Facultative anaerobes

Organisms that can survive in both aerobic and anaerobic environments.

Fermentable carbohydrate

Substances like glucose that bacteria can ferment to produce energy.

Ammonium ion (NH4+)

A source of nitrogen used by bacteria in certain growth media.

Alkaline agar

Agar that turns blue due to metabolic byproducts of citrate-utilizing bacteria.

Motile bacteria

Bacteria that can move and spread throughout a medium, displaying a fuzzy appearance.

Non-Motile bacteria

Bacteria that do not move from the stab line and appear clear.

Acetoin

A neutral fermentation product identified in the Voges-Proskauer test.

Sulfide

A compound formed by the reaction of hydrogen sulfide with iron, resulting in a black precipitate.

Enteric pathogens

Harmful bacteria within the Enterobacteriaceae family, such as Salmonella and Shigella.

Gram-negative rods

A category of bacteria distinguished by their cell wall structure; includes many enterics.

Semisolid medium

A growth medium with reduced agar concentration, allowing for the observation of motility.

Red color (in VP test)

Indicates positive neutral fermentation; acetoin present.

Yellow color (in MR test)

Indicates negative acid production; no fermentation of glucose.