In article <9410270708.AA25035 at luxor.latrobe.edu.au>,
gendjc at LUXOR.LATROBE.EDU.AU wrote:
> Can anyone help? We've been getting more and more infections of our
> fly medium. ...
On the rare occasions when we bacterial infections become extremely
troublesome, we have temporarily changed mould inhibitor. We normally use
proprionic acid buffered with phosphoric acid to pH4 (unionised proprionic
acid is the active inhibitor). Switching to unbuffered nipagin as an
inhibitor changes the pH of the medium, and previous infections often
don't propagate. The medium is prone to different infections, which is why
we soon change back to our original recipe, but the initial infections
don't always recur. Further, one can put the flies onto fresh medium for
one day to encourage them to excrete most of the infection before
switching to the new formulation.
ICRF Developmental Biology Unit, Oxford
d_horowicz at icrf.icnet.uk