BISC209/S12: Lab9

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Wellesley College-BISC 209 Microbiology -Spring 2012


Today you will have a lab practical exam designed to assess your mastery of basic tools, techniques, and theoretical information on which the field of microbiology is based.


In lecture on Monday April 9 you will learn how to use a public data base to analyze your sequencing results. Please bring your computer, if possible, to lecture that day and make sure you have downloaded any recommended software before you come to class. Dr. Klepac-Ceraj will provide information about downloading software in an announcement to Sakai.

Graded Assignment: Make separate figures and text for the antibiotic assay (if any of your site teammates indicated the presence of an antibiotic producer) and interactions assays. Use the Google doc table of the tests performed on the isolates from your soil community (include your teammates' isolates from the same sampling site for this assignment) to make a Table and write the results narrative for this table. You should include in the table: Gram stain, enrichment/selection medium, description of the colony morphology, description of the individual bacteria shape (cocci, bacilli, spirilla) and any useful descriptors ie., large, small, bullet shaped, in chains, etc., evidence of endospores (either endospore stain positive or visualization of empty areas in vegetative cells on Gram stain), & motility. Include metabolic tests such as nitrate reduction and mannitol fermentation. Leave out the interaction assay and the antibiotic producers test (if your site had a positive) in this table and make separate results figures from photographs of those plates and discuss those findings in separate sections in results. Work with ALL of your sampling sites' interaction assays on this results section and a photo of any positive antibiotic producers from your sampling site for that section of this draft results. If your site had no positive antibiotic producers, you can include this test and its negative results in your table with out a photo or separate section.

The results narrative for the table of tests performed on the isolates might start out, "In order to show structural and metabolic diversity as well as the potential for community behavior (co-operation and/or competition) among members of a soil community, nitrogen cycling bacteria & spore-forming bacteria were enriched and selected using media and protocols described in Materials and Methods. Once in pure culture a few soil community members of these groups and other interesting bacteria isolated on non-selective media were visualized using staining techniques for cell wall structure in a Gram stain, production of endospores with Shaeffer-Fulton endospore stain, the presence of capsules with a negative nigrosin stain, and flagella with a flagella stain. Additionally motility testing was performed on each isolate using soft agar deeps. Evidence for a role in the nitrogen cycle was assessed by________. (continue to describe any other testing you include in your table)......Table 1 shows the results of this testing."

After this results section introduction, you can then analyze the findings in a narrative with the goal of using the evidence in the table to answer our experimental question, "is there evidence for diversity and functional co-operation and competition among the bacteria isolated from your soil community?"

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