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BISC209/F13: Lab2: Difference between revisions
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Today you will complete your first investigative goal in our semester long project: assessing abundance of a soil microbial community by enumerating its microbes by two methods, one culture dependent and one culture independent. Today you will also continue acquiring and practicing skills used by working microbiologists. You will complete your tests for abundance today. The results of the fluorescent DNA stain are available and your plate counts are ready to assess. In addition, you will continue to isolate a few bacteria of interest from your soil community in order to show evidence for richness (diversity) and potential for co-operative and competitive behaviors among community members. Next week we will begin testing the whole soil microbial community : a culture-dependent assessment of carbon source utilization diversity. | Today you will complete your first investigative goal in our semester long project: assessing abundance of a soil microbial community by enumerating its microbes by two methods, one culture dependent and one culture independent. Today you will also continue acquiring and practicing skills used by working microbiologists. You will complete your tests for abundance today. The results of the fluorescent DNA stain are available and your plate counts are ready to assess. In addition, you will continue to isolate a few bacteria of interest from your soil community in order to show evidence for richness (diversity) and potential for co-operative and competitive behaviors among community members. Next week we will begin testing the whole soil microbial community : a culture-dependent assessment of carbon source utilization diversity. | ||
=='''Abundance: Finishing the Standard Plate Count'''== | =='''Abundance Test 1: Finishing the Standard Plate Count'''== | ||
Last week you started a standard plate count of the culturable microbes in your soil sample on dilute nutrient agar. Today you will complete that plate count to get one kind of enumeration of the microorganisms in your soil community. Find the plate(s) among those of your serial dilution that contains 30-300 colonies. You will not assess plates with well over 300 colonies or under 30; they should be designated as "invalid" in your lab notebook and on the bottom of the plate. Count all the surface and subsurface colonies on the replicate valid plates (those with 30-300 colonies). The colonies can be more easily counted by using a Quebec Colony Counter which allows proper illumination, a grid overlay, and slight magnification of the plate surface. (There are two colony counters in the lab.) <BR><BR> | Last week you started a standard plate count of the culturable microbes in your soil sample on dilute nutrient agar. Today you will complete that plate count to get one kind of enumeration of the microorganisms in your soil community. Find the plate(s) among those of your serial dilution that contains 30-300 colonies. You will not assess plates with well over 300 colonies or under 30; they should be designated as "invalid" in your lab notebook and on the bottom of the plate. Count all the surface and subsurface colonies on the replicate valid plates (those with 30-300 colonies). The colonies can be more easily counted by using a Quebec Colony Counter which allows proper illumination, a grid overlay, and slight magnification of the plate surface. (There are two colony counters in the lab.) <BR><BR> | ||
