Essay Isolated Colonies And Soil Samples

1626 Words Sep 23rd, 2014 7 Pages
Isolated Colonies and Soil Samples A. Purification of Serratia marcescens and Staphylococcus epidermis The objective was to grow isolated colonies on a nutrient agar medium (NA). Many microorganisms found in soil are able to grow on this medium. Since there are many organisms that are found in the soil, only a few of this organisms are adapted to live in this specific medium obtained. The NA plate is the first way to isolate microorganisms because the organisms that will be left on the plate will be those who can live on the complex medium. The process of isolating a colony is done by “streaking out” isolated colonies found in a sample. Streaking out uses a sterile loop to dilute the sample and distribute single cells on a section of the medium after incubation. It usually takes more than one time to obtain isolated colonies. The results of my isolated colonies can be seen in figure 1.1. B. Examination of S. marcescens and S. epidermis by Phase Contrast Microscopy In order to observe the motility and shape of the single cells, they were viewed using phase contrast. This was done by using a sterile look to obtain cells and distributing the cells on a microscope slide. To visualize the cells, the 40X objective lens was used and the microscope needed to be focused on the specimen. The results of S. marcescens and S. epidermis under phase contrast can be seen in figure 1.2. From these results I could see that S. marcescens are rods and motile, and S. epidermis are coccoid…

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