Bioluminescence

The Plan

• Characterise the transfer function of PoPs + CHBT --> Light

The Theory

• The Luciferin Cycle:

Amazing mutant

paper on cloning the lux operon from Ponyfish Photobacterium leiognathi into E.coli, by the E.coli mutant 43R the luminescence output could be increased dramatically to near native levels. --> find out what 43R does! [http://www3.interscience.wiley.com/cgi-bin/fulltext/120766166/PDFSTART Chan et al. 1991] suspects negative effectors in wild-type E.coli, but not in the mutant or in P.leiognathi, inhibit luminescence. If this is the case, it might be difficult to mimic the mutant phenotype with genes imported on a plasmid.

[http://www.springerlink.com/content/vlxb2c59xut1htd8/fulltext.pdf Ulitzur et al. 1997] describes phenotypes like 43R being generated by deletions in the H-NS gene, fancy that. Apparently H-NS acts as a pleiotropic transcriptional repressor, with particularly strong effects on a certain set of promoters. Mutants have a reduced expression of a flagellar protein and are non-motile, but fully viable. In fact they appear to grow faster. However, H-NS has been implicated in E.coli thermostability.

ADLA

The Abrupt Decline in Luciferase Activity is a phenomenon described for bacterial luciferase in E.coli in stationary phase of growth (see [http://www.springerlink.com/content/w73k840k27866462/fulltext.pdf Koga et al. 2005]) The paper identifies two mutants, HupA and an N-terminal deletion of H-NS for which ADLA does not occur. hns205, the mutation necessary for quiescence is a C-terminal deletion. We should find out whether the phenotypes are the same, which would be sweet if we ended up doing quiescence as well.