Microbiology Assignment

Microbiology Assignment
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Question 1: Colony Morphology
Colony morphology refers to the orientation of bacteria or fungi colonies on the agar substrate. Analysis of the microorganism size, shapes, coloring, margins, and consistency is the primary step in identifying unknown microorganisms. In a microbiology lab, the specimen is inoculated into an agar plate and incubated for 18-24 hours, which allows the growth of microbial colonies. The visual analysis of the settlements is essential in classifying the microbes, critical in identifying appropriate tests.
Question 2: Growth on Slants
Growth on agar slants is a common way of incubating bacterial cultures for microbial analysis. Boiled agar is put on a test tube and allowed to cool while in a slant position. The slanting of the growth culture gives microorganisms a large surface area for growth within the test tube. Growth on slants is essential in the identification of bacterial cells through microbial analysis techniques. Besides being useful in maintaining bacterial cultures, agar slants allow microorganisms to divide faster, which provides enough cells for microbial analysis using the microscope.
Question 3: Growth in Nutrient Broth
The nutrient broth is a culture medium that is useful in developing different classes of microorganisms with new nutritional specifications. The broth comprises beef extracts with peptones as the main ingredients. The main procedure involves the dissolution of the powder in distilled water and put in test tubes before sterilization. The nutrient broth is a common choice of medium in microbiology since it supports several classes of microorganisms regardless of their oxygen requirements.
Question 4: Fluid Thioglycollate Medium (FTM)
Fluid Thioglycollate broth is a medium that is useful in the testing of aero tolerance of microorganisms. The medium primarily comprises 0.075% agar, Thioglycollate, thioglycolic acid, L-cysteine, Vitamin K1, and hemin, which, support the growth of medically essential microbes. Both agar and thioglycolic acid are necessary to create an anaerobic environment in the test tubes, which allows the bacteria to thrive anaerobically. FTM is essential in separating specific microbes from the blood when there is suspicion of an infection.
Question 5: All Phenol Red Broth sugars
The principle behind all phenol red broth sugars is to differentiate gram-negative bacteria through sugar metabolism. The method involves using three classes of phenol red broths containing glucose, lactose, and sucrose. The results involve the observation of color change depending on changes in pH. At a pH of 6.8, the broth turns yellow, indicating the production of acid. If an organism does not metabolize glucose, the breakdown of peptones results in ammonia production, which turns the medium fuchsia at a pH of above 7.4.
Question 6: Methyl Red-Voges-Proskauer Test
The principle behind MR-VP tests is to identify the fermentation pathway that a microorganism uses to breakdown glucose. The basic idea is to determine the end products of anaerobic respiration that converts sugars to acids. The acid can be unstable; thus, it can quickly convert to neutral compounds. The method involves incubation of a test specimen in MR-VP broth for 48 hours and observation for color change on the addition of methyl red indicator and drops of Barritt's 1/A and 2/B reagents. For MR, if the test tube turns red, then the microbe can break of sugars in mixed fermentation. For VP, if the color changes to pink or red, the result has positively confirmed acetoin's presence from the breakdown of 2,3-butanediol.
Question 7: Nitrate Reduction
The principle behind nitrate reduction in the anaerobic breakdown of nitrates in a culture medium to ammonia. The biochemical test analyzes the production of nitrate reductase, which is responsible for the removal of nitrate. The resulting ammonia reacts with sulfanilic acid and naphthylamine reagent resulting in the formation of red coloration. The method involves the injection of unknown organisms in nutrient broths and testing for nitrogen gas presence after incubation. Denitrification in the Durham tubes indicates that the bacteria were able to utilize nitrates, leading to nitrogen gas production. The red end color illustrates that nitrate was available in the medium.
Question 8: Oxidase Test
The oxidase test principle is detecting the presence of cytochrome C oxidase, an enzyme resulting from aerobic respiration. The enzyme acts as the electron receptor and other enzymes that undergo oxidation and reduction by accepting electrons from H2. The test for the ability of a microorganism to produce cytochrome C oxidase uses the tetramethyl-p-phenylenediamine dihydrochloride reagent present in the filter disk. The reagent plays t...