Bacterial Smear Preparation and Simple Staining

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OBSERVATION OF BACTERIAL CELLS VIA MICROSCOPE
In this experiment, we have learned several basic molecular biology techniques. Here they are; Simple staining: Only one type of dye used for simple staining and it stains all cells the same color. Creating contrast between cell and background to observe cell morphology is aimed. Differential staining: A differential stain uses more than one dye and stains different kinds of organism with different colors. Positive staining: If cell itself is stained it is called positive staining. It sticks with specimen and gives its color. Negative staining: If background is stained and cell visualized by making use of contrast difference between backgrounds and cells, it is called negative staining. Simple staining

Salmonella anatum obtained from liquid broth and agar plate was stained with methylene blue, safranine and crystal violet dyes respectively. Sample taken from agar plate is much more concentrated than sample from broth. We expected to observe the rod-shape for these bacteria and see that this is actually rod-shaped. Some parts of prepared smears were difficult to observe due to high concentration of smear. It should be washed away during smear preparation. In addition, while performing smear preparation such as high or low heat fixation process or not well washing off excess dye may cause this. Moreover, it is important to be careful when taking sample from agar plate if too much bacteria is taken, it will effect the observation of them. They will look like to attach each others. And we cannot differentiate the shape of bacteria if too much sample is taken. Temporary wet mount

It is a technique in which sample suspending in liquid placed on glass and covered with cover slip. Live cells can be examined under microscope by using this technique. Saccharomyces cerevisiae which is known to be immobile (and 5-10 micrometer in diameter that make it easy to observe) yeast was observed under microscope to observe its movement...
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