![]() ❷ Combine the bottom and lid of an incubation box and distribute water in the cells to create a humid atmosphere. How will you know if the microbe being tested produces urease a. ❶ Take a single isolated colony (from a pure culture) and make a bacterial suspension in sterile distilled water (0.5 McFarland). During incubation, bacterial metabolism produces color changes that are either spontaneous or revealed by the addition of reagents. ![]() □ A bacterial suspension is used to rehydrate each of the wells and the strips are incubated. VP: positive brownish red band at the top (organisms capable of butandiol or acetone products) neg is a lighter less obvious brownish yellow. So, gelatin hydrolysis test can be used to identify and differentiation of gelatinase producing and non-producing microorganism. Without DNAse enzyme, the HCL precipitates out the undestroyed DNA. There are 2 kinds of DNAse agar that can be used.: The first medium has no indicator, but is does require HCl reagent to be added after growth has occurred on the plate. 1- ONPG test : The ONPG test is used to detect the enzyme β-galactosidaseĢ- ADH : Decarboxylation of the amino acid arginine by arginine dihydrolaseģ- LDC: Decarboxylation of the amino acid lysine by lysine decarboxylaseĤ- ODC: Decarboxylation of the amino acid ornithine by ornithine decarboxylaseĥ- CIT : Use of citrate as sole carbon sourceĨ- TDA (Tryptophan deaminase) : Detection of the tryptophan deaminase enzyme (detected by adding Ferric chloride).ĩ- IND : Indole test : production of indole from tryptophan by the enzyme tryptophanase (Indole is detected by adding Kovac's reagent).ġ0- VP : The Voges-Proskauer test for the detection of acetoin (acetylmethylcarbinol) produced by fermentation of glucose by bacteria using the butylene glycol pathwayġ1- GEL : Production test of the enzyme gelatinase which liquefies gelatinġ2- GLU : Glucose fermentation (hexose sugar)ġ3- MAN : Fermentation of mannose (sugar hexose)ġ4- INO : Fermentation of inositol (cyclic polyalcohol)ġ5- SOR : Fermentation of sorbitol (sugar alcohol)ġ6- RHA : Rhamnose fermentation (methyl pentose sugar)ġ7- SAC : Fermentation of sucrose (disaccharide)ġ8- MEL : Fermentation of melibiose (disaccharide)ġ9- AMY : Fermentation of amygdalin (glycoside)Ģ0- ARA Fermentation of arabinose (pentose sugar) Identify a positive and negative test for each of the methyl red and VP tests. Deoxyribonuclease is an exoenzyme excreted from the cell which will break the DNA down into smaller molecules. ![]()
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