University:
Northwest College
Course:
MOLB-2210 | General Microbiology
Academic year:

2023
Views:

53

Pages:

9
Author:

Yesenia M.

nitrate reduction/oxidase/catalase test. Nitrate reduchon test. Remember: were testing to see if bactena can nduce nitrate Procedure: -Inoculate nitrate broth tube using loop. - Incubate at 35°C x2days. AFTER 2 DAYS... -examine the tube for gas production (+) gas = (1) result (nitrate was reduced) - Add 5 drops of (reagent A) dimethyl-2-naphthylamine + 5 amps of sulfanilic acid (reagent B) - Shake gintly - (t) result - furns red in 30 seconds = (+) for NITRITE. - (-) result-color change further tested taimu. - add small pinch of zino - (-) result = turns red in 20-30 seconds Onitrate reductase emyme it's negative because it means itrate is present and was & reduced. - color change = (+) test. nitrate present nitrate was reduced * Fo gas/nitrite Oxidase test. enzyme- test that is used to identify prescence of cytochrome Coxidase. (cytochnmee) Cytochrome (carries clections to 02. (final election acceptor.) Procedure: -place an oxidase test strip in a petri dish (or a slide) and moisten an area of the Strip water (so it adheres, does move around.) - smear 3 or 4 well-isolated colonies Unto the moistened areg Taloop. (1) for Cytochrome = pink color change *(DARK PURPLE c (Pink purple blackish color.) (?) COLOR!)* -If reagent applied directly to colonies on the plate Colonies (t) for cytochrome Dark purple color oxidase reagent is tetra-methyl-p-phenylenediamine dihydrochlonde (TMPD) Catalase test Tests for the prescence of catalase. Remember catalase breaks hydrogen peroxide to water and Oxygen. Hs Important to break it down blc If flydrogen atoms combine T 02, Hydrogen peroxide is formed and that is LETHAL to the cell. (1 ROS production) Procedure: - snoculate the plate lead to activation of - Incubate, inverted at 35°C for 24-48hrs ↑ Ros can kad to damage to protems, nuckycacids, lipids/membranes / organelles Mhic cell death Such as apoptosis. After24-48hrs... -Transfer a colony to a clean slide by using a toothpick * - Drop hydrogen peroxide on the organisms and observe for bubbles (+) Catalase test = bubbles. Catalase (-) catalase test = bubbles. Fyl: gas in bubbles is Oxygen bic remember Catalase breaks Hydrogen peroxide to *120*02*