Manipulation of Bacteria Essay

3385 WordsMar 4, 201114 Pages
MANIPULATION OF BACTERIA INTRODUCTION: In this experiment that we performed, there were many methods that were used to help us manipulate and identify the bacteria E.coli on a MacConkey agar plate. The first part of the experiment involved the methods of manipulating, identifying and counting the bacteria and the second part was to find out whether the bacteria E.coli was the only type found in the given area by gram staining. E.coli was the chosen bacteria for this type of experiment. It is a gram negative bacterium that will grow rapidly given ‘any culture medium with the necessary energy source, nutrients, pH, and temperature’. Therefore, MacConkey Agar being the medium for its growth will enable us to achieve the experiment…show more content… METHOD FOR MANIPULATION AND IDENTIFICATION OF BACTERIA  Lab coat and gloves have to be worn for safety  Start of by ensuring the work area and equipments are clean so that there is no contamination to your work.  Taking the sterile loop without holding the loop side dip inside the given bacteria culture provided and streak the MacConkey agar plate shown below.  The first loop L1 is to be streaked as shown. The loop is then to be put into the sharps bin immediately to prevent contamination of the work area and other equipments.  Taking a fresh loop streak L2a then using the other side of the same loop, streak L2b also.  A third loop L3a is then used to streak the bottom right, then flip the other side and streak the bottom left corner L3b like the image shows.  Lastly, take the last loop L4 and create a squiggle in the middle of the plate. This is the streaking procedure so that the bacteria will be spread out as much as possible for better results during the count.  This is then covered and labelled ready for inoculation to make it easy to identify.  For the viable count, a set of dilutions have to be made. Place the 9 tubes in their stand and add 900ul of PBS into each bottle adding it to the neat sample of bacteria culture first.  Sequentially, add 100ul from the previous sample to the next e.g. take 100ul from the neat sample dilution into the following 900ul forming 10
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