infection of medium

gendjc at LUXOR.LATROBE.EDU.AU gendjc at LUXOR.LATROBE.EDU.AU
Sun Oct 30 23:33:08 EST 1994


I recently asked for help with infection of medium. Thanks everybody!
I think we can outwit nature yet again, and by god that makes me happy.
Here are the suggestions:
-Try using dextrose monohydrate in place of raw sugar.
-Try autoclaving the medium after it is poured into the bottles and 
plugged.
-If the infection is being carried over by the flies try sterilising the eggs 
by dechorianation and EtOHwashes.Transfer the flies more often and 
throw out any contaminated cultures.
-General advice for unacceptable growth of muck on your fly food: 
autoclave everything, including the foodif you have to! Maintain sterile 
technique if possible.
-Tegosept (10% (w/v) methyl p-hydroxybenzoate in 95% ethanol)
-Prepare food with 0.5-1% formaldehyde and hold the flies in this 
medium for a few days (transferring them to freshformaldehyde food 
every two days) before moving them onto regular food.
-100 units/ml        penicillin G, 0.2 mg/ml           streptomycin sulfate
-10 mg/L of chloroamphenicol
-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.
thanks again
dave clancy
la Trobe uni.
melbourne, Australia.




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