26 June 2008
Bacteria Mystery Solved!
Used spec in Tatar Lab (5th floor BioMed) and obtained reading of original culture, 1/10 dilution, 1/100 dilution and obtained readings that were expected.
- Original culture: 1.17 (expected, out of range of spec)
- 1/10 dilution: 0.401
- 1/100 dilution: 0.047
These are expected from a regular spec. (UV/vis) so from a nanodrop (1mm area instead of 1cm) readings a degree less than 10 would be expected
- Our current readings have been correct
- With the nanodrop, stationary phase is >0.1 and so logarithmic phase is >0.01.
Labview has been giving us problems
- Reading continuously decreases
- Output voltage won’t equal the voltage we set (won’t go past 5V)
Daniel Ludwig suggests:
- Try putting a for loop around voltage reading but inside while loop to make an alternating voltage (Daniel)
- Try using different resistors (smaller than 1Mohm) because our readings have been around 100 or 200kohms so a smaller resistor would give more accurate readings (John S. let us borrow his resistor kit)
Plan for the day:
Test if our bacteria work:
- Add arabinose to pVJ4 culture and see if resistance changes with multimeter
- Talk to Daniel (and hopefully Jerry Daniels) to try and fix our apparatus
- Meeting with Jill Kreiler @3:00pm
- Make culture of pVJ4 tonight from glycerol stock to miniprep tomorrow for sequencing
Tried running a freeze-thaw test with 10mL of our sample:
- Plate number 6 (with culture) gave a completely different reading than the two other plates with culture (300Mohm vs. 50-60Mohm
- Tried switching alligator clips→ reading completely changed (300Mohm→ 60Mohm)
- Conclusion: alternating voltage/current is necessary to prevent migration of ions
- Attempted implementing an alternating voltage with LabView but did not work→ will call Daniel Ludwig tomorrow for his help
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