BHS002: Microbiology & Biochemistry
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University of Bedfordshire
Added on 2020-05-04
BHS002: Microbiology & Biochemistry
University of Bedfordshire
Added on 2020-05-04
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Microbiology and biochemistryNameName of the classInstructorInstitutionDateNo. Of words: 3026
1. Aseptic techniqueAseptic technique is defined as a laboratory skill used by microbiologists for various procedures including isolation of pure cultures, executing microbiological tests and transferring cultures among other functions. The technique prevents contamination of cultures from bacteria found in the environment like the microbes found on the researchers body that might contaminate cultures, hence interfering with the actual laboratory results. Besides, aseptic technique can also be used to isolate individual species of microorganisms from a mixed culture so as to get a new culture. 2. Necessary precautions that ensure aseptic technique especially when manipulating specimens in a laboratory. There are a myriad of factors that should be taken for proper aseptic method especially when manipulation samples in the lab and they include; The first precaution is to ensure that you avoidcross contamination by working with one microorganism at a time. Switching of cell lines or microorganism either intentionally or accidentally do occur most of the times which can lead to misleading or erroneous informationSecond, work areas and biological safety cabinet’s needs to be thoroughly cleaned as well as disinfected between vulture sessions. It is also recommended to avoid routine antibiotics especially during cell culture media, because antibiotics can cover the underlying contamination that is not of target by antibiotics.Above all, the most basic procedures include using proper antiseptic procedure, wearing clean dust coats and thoroughly washing of hands to ensure microorganisms are introduced into the mammalian cell cultures Streak plate method1. The need for streaking bacterium on growth media with a loop The aim of streaking bacterium is to isolate or define a given colony from mixed population although streaking is ideal for separating, it does not work with larger volumes neither does it give the concentration count.
2. How streak plate technique is done as well as when the loop is sterilized or when to use a freshsterile Start by cooling your loop by touching it on the sides of the agar plate. Next, put the nichrome wire into a culture of the bacteria mixture. Pull the lid off your plate, insert the nichrome wire and then drag it over its top surface. This should be done in a back and forth zigzag motion as shown in the diagram below.Escherichia coli1. What’s the natural habitat for Escherichia coli? The main habitat of this bacterium is in the gut of organisms (both animals and people) 2. The range of infections that are caused by strains of Escherichia coli? The main infections are gastroenteritis, urinary tract infections, gut infections with severe bloodydiarrhea, intra abdominal infections. Other infections are meningitis, pneumonia, infected bones/joints, and infections of the skin or tissues.3. All strains of Escherichiacoli are not equally able to cause infections or diseases because theyare harmless strains that live in the human colon and they are of benefit since they produce vitamin K which helps in synthesis of proteins in the body.
4. The property of Escherichia coli strain used for the untrained microbiologists especially in the first year practical is virulence properties5. The reason to why plates were inoculated with presumed Escherichia coli incubated at 37 degrees Celsius was to promote the growth of target group of E coliSelective & differential growth media1. Define the terms differential and selective growth media For the selective growth media, it allows specific type of species to thrive as well as hinders the growth of other species while the differential growth media applies when distinguishing closely related animals.2. The likelihood appearance of Escherichia coli growing on MacConkey agar is the colonies that are pinkish to red in color and a bile salt precipitate surrounding the colonies.3. What property does the colour of E. coli growing on MacConkey agar indicate? The property is virulence.Contamination 1. The reason to why you expect multiple contaminants to thrive on nutrient agar plates other than MacConkey agar is due to the subtype of nutrient agar which is the main medium for microbial studies. Besides, it can also be used during routine cultivation of species. Also, the nutrient agar plate does not grow one type of bacteria over the other. On the other hand, MacConkey is an agar where the Gram negative grows. What is more is that Escherichia coli grow in red colonies because of the PH indicator. Also, it is important to mention that MacConkey agar powder is of two forms; one with carbohydrate lactose in it plus the other with no added sugar and because Escherichia coli ferment carbohydrates to acids, you can put different forms of sugar to the sugar free MacConkey agar to check whether red colonies will develop. In case they develop, it means that the Escherichia coli strain being used can use such sugar
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