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| <font size="+1">Using General Purpose Media for Isolation of Soil Bacteria in a Mixed Population</font size="+1"><BR> | | <font size="+1">Using General Purpose Media for Isolation of Soil Bacteria in a Mixed Population</font size="+1"><BR> |
| Please watch the YouTube video on streaking for isolation and pay attention to your instructor's demonstration: http://www.youtube.com/watch?v=eyoW18Fzb3o<BR> | | Please watch the YouTube video on streaking for isolation and pay attention to your instructor's demonstration: http://www.youtube.com/watch?v=eyoW18Fzb3o<BR> |
| Directions for [[BISC209/F13: Streaking for Isolation| Streaking for Isolation]] are found in the [[BISC209/F13:Protocols| Protocols]] section of this wiki. <BR><BR> | | Directions for [[BISC209/F13: Streaking for Isolation| Streaking for Isolation]] are found in the [[BISC209/F13:Protocols| Protocols]] section of this wiki. <BR> |
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| '''Streaking for Isolation from a Soil Extract:'''<BR>
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| Each '''team''' of students will '''make a soil extract''' from one gram of their soil sample.
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| <li>After recording the weight of the individual aluminum weigh boats, combine the dry soil into one weighing boat, mix gently, and then weigh out 1 gram of the mixed oven dried soil on waxed weighing paper.
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| <li>Add the 1g of mixed dried soil to 100ml of sterile water. This is the equivalent to a 1/100 dilution.
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| <li>Put the soil suspension in a pre-disinfected blender jar, as you did last week, and blend at highest speed for 3 pulses of 10 seconds each.
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| <li>Pour the blended suspension back into the Erylenmyer flask and add the stir bar.
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| <li>Put the flask on a magnetic stirrer and allow the soil to stir for 15-30 minutes and to settle for an additional 15-30 minutes.
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| <li> Note that using liquid SOIL EXTRACT as your inoculum is analogous to using a broth culture source, you should follow the steps carefully for Broth to Plate transfer found in [[BISC209/F13: Aseptic Transfer| Aseptic Transfer]] and in [[BISC209/F13: Streaking for Isolation| Streaking for Isolation]], both found in the [[BISC209/F13:Protocols| Protocols]] section of this wiki. <BR><BR>
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| Aseptic transfer and streaking for isolation are crucially important skills in microbiology. When you are ready to streak out your first plate (after you have read the directions carefully, asked questions to clarify any confusion, and practiced your best technique on an empty plate or piece of paper), call your instructor over and ask her to watch you streak out your first plate. She will give you pointers to enhance your success at repeating this technique on a second plate. Your goal is to have well-separated single colonies when you evaluate your streaked plates next week. Label the plates with your initials, date, lab section, soil sample identifier information, and medium name. Incubate one plate at room temp and one plate at 30°C in the racks assigned to your group or Lab section.
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| '''Isolation of Bacteria by isolation streak:'''<BR> | | '''Isolation of Bacteria by isolation streak:'''<BR> |
| <ul> | | <ul> |
