Applying Staining Techniques to View and Identify Bacteria Essay

693 Words 3 Pages
Abstract The main objective of this lab was to identify different bacteria by simple, negative, and gram staining. To view each bacteria cell, the bacteria was transferred aseptically to a slide, and they were then viewed by using oil immersion, by a light microscope. From this lab, it was determined that E. coli and B. megaterium are gram negative and B. subtilis and S. Marcesans are gram positive.

Introduction The purpose of this lab was to view the different characteristics of bacteria by applying various staining techniques. It is important to know the make up if a certain bacteria so an antibiotic may be engineered to destroy the bacteria. From the gram stain, it was possible to determine which bacteria was gram positive
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Distilled water
Three different staining procedures were then used for all four types of bacteria. The directions for each staining process can be found on pages 18-19 of the lab manual. For simple stain, bacteria was removed with a sterile inoculating loop and placed on a glass slide. Methylene blue was then applied until the slide was covered. Distilled water was then poured on the slide until the methylene blue was removed. The slide was allowed to dry. Next, oil was placed on the slide so that the oil objective lens on the light microscope was employed. The bacterium was viewed and a sketch was made. For the negative stain, a loopful of bacteria was placed on a slide. A drop of Nigrosin solution was placed next to the bacteria, and the blood smearing technique learned in the first lab was applied to cover the slide with nigrosin solution. A sketch was then made. Gram staining was more complicated. First, two separate types of bacteria were used. One type was placed on one slide, and the other bacteria were placed on the opposite side. Both bacteria were also placed in the middle of the slide so they could be viewed together. Crystal violet, iodine and safranin were all placed on the slide and washed off with distilled water. Once dried, oil was applied to the slide, and it was ready to be viewed. Again a sketch was made.

Results The sketches were drawn on a separate piece of paper and then revised. A
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