Team:Goettingen/week15-2

V08_06

• Experiment:
  In order to test new agar compositions for the swimming assay over night cultures of E.coli MG1655 and RP437 were prepared.
  

V08_07

• Experiment:
  LB medium was inoculated with the over night culture and shaken until an optical density of 0.8 was reached. This time three different compositions were produced:
  M9 agar with tryptone solution soaked Whatman Filter Paper
  M9 agar with methionine solution soaked Whatman Filter Paper
  Agar containing 1% tryptone and 0,5% NaCl with additional tryptone solution soaked Whatman Filter Paper
  The cultures were dropped on the agar at a distance of 1 cm to the paper. Also this time each plate was prepared in duplicates.
  
• Observations & Results:
  The day after (8th of August) the strongest motility could be observed for MG1655 on M9 agar with tryptone as attractant. However it does not seem to be directed. RP437 did also show motility, but in a more moderate manner. Also here no chemotaxis was noticed.
  On the M9 plates with methionine as attractant no motility could be observed at all for either strain.
  On the tryptone containing agar plates a simliar outcome could be examined. MG1655 swims, but does not feature chemotaxis. RP437 in contrast did neither show any swimming nor chemotaxis.

V08_08

• Experiment:
  In order to test new agar compositions for the swimming assay over night cultures of E.coli MG1655 and RP437 were prepared.
  

V08_02

• Experiment:
  LB medium containing ampicillin was inoculated with the over night culture and shaken until an optical density of 0.4-0.6 was reached. Meanwhile ampicillin containing M9 agar plates were prepared and autoclaved Whatman Filter Papers were imbued with tryptone solution. Then the cultures were dropped on the agar at a distance of 1 cm to the paper. On each plate also colonies hosting the empty vector pUC18 were dropped in order to have a reference. Two drops were rather applied into the agar than onto as done before, because some paper predicted faster motility. Also this time each plate was prepared in duplicates.
  
• Observations & Results:
  Unfortunately, even after a week no swimming could be observed only growth. We assume that the medium might not provide adequate swimming conditions and therefore we plan to test more motile strains and alter the agar composition if necessary.

• Experiment:
  Since we recently received new E. coli strains that are more motile than our usually used laboratory stains new over night cultures of MG1655 and RP437 were prepared.
  

V08_03

• Experiment:
  This time the over night cultures were directly dropped to the swimming plates. In oder to test whether the medium or indeed our strains are responsible for the immobility of the bacteria the habitual M9 agar plates were prepared. However not antibiotics were used since the new strains are not equipped with any resistance yet. Then the autoclaved Whatman Filter Papers were imbued with tryptone solution were placed in the middle of the plate and the cultures were dropped on the agar at a distance of 1 cm to the paper. Also this time each plate was prepared in duplicates.
  
• Observations & Results:
  The following day (4th of August) no motility could be observed. Since both strains are known to move very quick and are supposed to swarm the whole plate during hours we suggest that the medium composition is indeed not suitable. However, two days after preparation of the swimming assay (5th of August) some evidence for incipient swimming was visible, which grew to small halos the following days. Nevertheless, the slow progress confirmed our resolution to reconsider the composition of the plates.