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BISC209/F13: Lab2: Difference between revisions
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→RICHNESS OF A MICROBIAL SOIL COMMUNITY: METABOLIC DIVERSITY: Structural Diversity in Cultured Bacteria from a Soil Community
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Directions for [[BISC209/F13: Streaking for Isolation| Streaking for Isolation]] are found in the [[BISC209/F13:Protocols| Protocols]] section of this wiki. <BR> | Directions for [[BISC209/F13: Streaking for Isolation| Streaking for Isolation]] are found in the [[BISC209/F13:Protocols| Protocols]] section of this wiki. <BR> | ||
'''Isolation | '''Streaking for Isolation from Soiid Medium:'''<BR> | ||
<ul> | <ul> | ||
<Li>You will use a new sterile cotton swab dipped into the oven-dried-soil extract to Swab section 1 of a pre-labeled plate of NA medium . | <Li>You will use a new sterile cotton swab dipped into the oven-dried-soil extract to Swab section 1 of a pre-labeled plate of NA medium . | ||
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<li>Check your plate for colonies daily and record your descriptions of the texture and shape of the colonies that appear. If any colonies arise that look tough and leathery or appear as "little, powdered-sugar volcanos", use the tip of a sterile toothpick to pick up a small but visible amount of growth (being careful not to touch anything but the tip of the colony) and "spread" the bacterial growth onto section 1 of a new glycerol yeast plate. (Inoculate one colony/plate.) Use your loop to isolation streak sections 2-4. Don't forget to flame your loop between sections! | <li>Check your plate for colonies daily and record your descriptions of the texture and shape of the colonies that appear. If any colonies arise that look tough and leathery or appear as "little, powdered-sugar volcanos", use the tip of a sterile toothpick to pick up a small but visible amount of growth (being careful not to touch anything but the tip of the colony) and "spread" the bacterial growth onto section 1 of a new glycerol yeast plate. (Inoculate one colony/plate.) Use your loop to isolation streak sections 2-4. Don't forget to flame your loop between sections! | ||
<li>We will select colonies of other potential spore-forming bacteria in lab 3. </ul> | <li>We will select colonies of other potential spore-forming bacteria in lab 3. </ul> | ||
Over the next few weeks you will continue to sub-culture onto new plates, using your best isolation streak technique. Your goal is to continue to streak out ONE CFU until you are sure that all the bacterial growth in a colony comes from a single mother cell (pure culture). In subsequent labs you will make a bacterial smear and do a Gram stain of these genetically identical bacteria and you will perform other tests from freshly pure cultures to explore the physical and metabolic characteristics of this isolate. <BR><BR> | Over the next few weeks you will continue to sub-culture onto new plates, using your best isolation streak technique. Your goal is to continue to streak out ONE CFU until you are sure that all the bacterial growth in a colony comes from a single mother cell (pure culture). In subsequent labs you will make a bacterial smear and do a Gram stain of these genetically identical bacteria and you will perform other tests from freshly pure cultures to explore the physical and metabolic characteristics of this isolate. <BR><BR> | ||
Some bacteria often form tough leathery colonies, so transfer of these bacteria to new media to start a sub-culture is sometimes difficult. The powdery area may be spores which would be interesting to visualize later. To isolate | Some bacteria often form tough leathery colonies, so transfer of these bacteria to new media to start a sub-culture is sometimes difficult. The powdery area may be spores, which would be interesting to visualize later. To isolate spore formers try to "break off" a piece of the colony with your sterile loop or with a sterile toothpick and transfer that whole piece of a colony onto zone one of the new plate. Then use your loop for streaking out the other zones. The tiny spores on the surface of the colony are likely to transfer to the next plate or tube when you work with it. (That's a good thing this time.) <BR><BR> | ||
Your team will obtain additional Streaking for Isolation practice by following the directions for ISOLATION using the spread plates that you inoculated with your soil extract last week. This process will continue your attempt to find a diverse group of interesting bacteria in your soil community. <BR><BR> | Your team will obtain additional Streaking for Isolation practice by following the directions for ISOLATION using the spread plates that you inoculated with your soil extract last week. This process will continue your attempt to find a diverse group of interesting bacteria in your soil community. <BR><BR> | ||
