Microbiology Practical 1. Describe the full theory behind the catalase test. Why must plain agar be used? Catalase is an enzyme that converts hydrogen peroxide to water and oxygen. Aerobic and facultative organisms have developed various protective mechanisms against the toxic forms of oxygen (especially superoxide radicals as they can potentially inactivate vital cell components)…
Download full paperFile format: .doc, available for editing
Download file to see previous pages
Catalase test is used to identify organisms that are capable of producing catalase enzyme. The enzyme converts toxic H2O2 into water and oxygen and thereby prevent the formation of highly dangerous hydroxyl radicals. 2H2O2 Catalase 2H2O + O2 To test catalase activity, the culture must be of 18- 24 hour as old culture lose catalase activity and may display false negative test. The emerging bubbles in catalase positive test is due to the formation of oxygen gas. Aerobic bacteria in general display catalase positive test while most of the anaerobes are deficient in catalase enzyme indicating the sensitivity of anaerobic bacteria towards oxygen. E.g. Catalase positive organisms are Micrococcus spp. and Staphylococcus spp. Catalase negative organisms are Enterococcus spp. and Streptococcus spp. Bacto Agar or plain agar is used for the study as it contains calcium and magnesium. On the contrary, blood agar are unsuitable to carryout catalase test as blood contains catalase (Web: Catalase test, n.d.; Pelczar, 1993). 2. Explain the principle of Oxidase test. Oxidase test is a test for the presence of cytochrome oxidase (playing vital role in electron transport chain or ETC) which catalyses oxidation of reduced cytochrome by oxygen. Cytochrome oxidase transports electrons from the ETC to oxygen, the terminal electron acceptor. The principle is utilized to test the organisms for the production of cytochrome oxidase. To test this ability of microorganisms, artificial electron donors and acceptors are provided. As soon as the electron donor (1.0-1.5 percent solution of tetramethyl p-phenylene diamine hydrochloride) is poured over the colonies, it is oxidized by cytochrome oxidase. Oxidase positive colonies become maroon, purple and black in 10-30 minutes (Pelczar MJ. 1993). E.g. Members of Pseudomonadaceae and Enterobacteriaceae are oxidase positive (Pelczar, 1993). 3. Explain how Oxoid Chromogenic UTI media (Clear) works. Oxoid Chromogenic UTI media is a nonselective medium to isolate, differentiate and enumerate the pathogens prevalent in urinary tract and are responsible for urinary tract infection. The medium facilitates the differentiation and identification of E. coli and Enterococcus without undergoing confirmatory tests (Web. Dehydrated Culture Media, n.d.). The principle utilized is based on the difference in susceptibility prototypes of the microorganisms. For the efficacy of antimicrobial therapy, the organism must be identified to the species level. However, the prevalent species Enterococcus spp. and Escherichia spp. produce enzymes for the metabolism of glucosidase or lactose or both and aids identification. On the contrary other microorganisms may not produce enzyme for such substrate fermentation (Web. Dehydrated Culture Media, n.d.). The chromogen mixture present in the Oxoid Chromogenic UTI media (Clear) comprises artificial substrates or chromogens which are responsible for releasing different colored compounds when specific microbial enzymes released by Enterococcus spp. and Escherichia spp act on substrate molecules, thereby a differentiation process works for the detection of certain species or a group of microorganism (Isenberg and Garcia, 2004). For instance the chromogen X-glucoside is a substrate for ?-glucosidase enzyme of enterococci which form blue colonies while chromogen red-galactoside is utilized by enzyme ?-galactoside generated
...Download file to see next pagesRead More
Insulin can be synthesized technologically. During biotechnological production of insulin, scientists extract messenger RNA (m RNA) from a minced up sample of human pancreas. In this stage, introduced solvents remove the proteins. Next, reverse transcriptase enzyme copies pure messenger ribonucleic acid into a deoxyribonucleic acid (DNA).
It uses test reagents, which react with the compounds forming chemicals that range from pink to reddish in color, Alef & Nannipieri (1995). This procedure in conjunction with technics such as HPLC, GC/MS and other analytical methods that provide specific quantitative and qualitative analysis for site remediation purposes.
Upon interaction with a pathogen in the body these T cells produce a specific response. T cells can only be activated if they their receptors recognize the pathogen entering the body. The pathogens are recognized by the T cells with the help of the Antigen Presenting Cells (dendritic cells, macrophages etc).
To inhibit the spread of Cholera, various control measures can be used. One is the preventive measure where persons moving to areas susceptible to Cholera outbreak are advised on cautious water and food consumption
Some of these legislations include
Employment equality regulations act 2006, which prohibits discrimination, victimization, and harassment on the grounds of age and gender in the areas of employment and areas which provide vocational training.
The author states that differential media is a method that is utilized to distinguish one microorganism from the next in situations where both are growing in the same medium. Example; Eosin methylene blue is differential for the fermentation of lactose to disperse the individual cells across the medium surface.
The AIVs exchange RNA segments in the nucleocapsid and lysed from a cell to transform to a new virus. Type A influenza is highly pathogenic in humans and poultry to infect a wide range of hosts. The subtype of characterization of AIV includes hem
This practical involves three experiments which were carried out to quantitatively analyze and measure antibiotic susceptibility of various microorganisms. The first experiment investigates the effects of variables such as agar depth, presences of salt and inoculums size on the size of inhibition zones.
6 Pages(1500 words)Coursework
GOT A TRICKY QUESTION? RECEIVE AN ANSWER FROM STUDENTS LIKE YOU!
Save Your Time for More Important Things
Let us write or edit the coursework on your topic
with a personal 20% discount.