THE VIRTUAL EDGE: Lab 6 Cultivation of Bacteria II |
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Streak PlateAs mentioned in the previous lab, pure cultures are essential for microbiological studies. Obtaining a pure culture of bacteria is usually accomplished by spreading bacteria on the surface of a solid medium so that a single cell occupies an isolated portion of the agar surface. This single cell will go through repeated multiplication to produce a visible colony of similar cells, or clones. There are three methods commonly used to derive a pure culture:
All of these methods dilute or “thin out” a heavy population of bacteria across an agar surface. The spread plate technique was used in lab #5 to obtain isolated colonies. In this lab we will learn to streak a plate with a mixed culture containing more than one bacterial species. Since most bacterial samples encountered by a microbiologist (in the clinic, environment, industry, etc.) are mixed cultures, this is a very important microbiological technique. If this procedure is performed correctly, a number of isolated colonies will grow that will be a source of pure bacterial cultures. Streak plate - Triplet Streak. There are many variations of the streaking technique, but in this lab we will use the triplet streak as described here. Be sure to note the diagrams and description of the technique on the following page before starting with your streak plate. |
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Lab 6 / Pure Cultures: Streak Plate Method / Environmental Influences: temperature, osmotic pressure, and oxygen / Lab 6 Organisms Please take a few minutes to fill out a brief survey about your experience using the Virtual Edge: https://docs.google.com/forms/d/1yGbkF0KM92WBSk-IgS-EkjxkTKTQwhzuXmDsVpwRDoU/viewform Please email comments/problems to cboggs@uwyo.edu |
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Rachel Watson, M.S. |
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