[Drosophila] question: mortality problems in drosophila

Nelly via dros%40net.bio.net (by nellygidas from yahoo.fr)
Fri Jan 11 10:54:27 EST 2008


Dear all,



I’d like to call for advice or suggestions from people of the Drosophila 
community who have encountered mortality issues in Drosophila lines.



Six months ago, the Drosophila pseudoobscura populations raised in my 
lab have suddenly shown high levels of mortality (80-90%), when the 
flies are 5-6 day old, particularly males. The flies that are still 
alive in the bottles look normal and have subsequent normal survival, 
although they seem to be a bit less productive. The problem has 
persisted despite trying several different procedures:



1) The room where the flies are handled was thoroughly cleaned (with 
dilute bleach and 90% ethanol) several days in succession and much of 
our equipment (plasticware, yeast etc.) was replaced.



2) An experiment was carried out to determine if the food was hosting 
some microorganism that could be the cause of the infection. This 
involved raising males and females separately on 3 different types of 
food medium; normal (cornmeal molasses medium), sugar agar or a potato 
based medium. Flies were transferred to fresh vials of the appropriate 
medium every day for around 10-14 days. The vials were then observed to 
see if anything grew on these substrates; it was assumed we could detect 
any microorganism present in the food. There was no obvious presence of 
a microorganism growing on any substrate and the survival of the flies 
did not differ according to which substrate they were kept on.



3) Finally, an antibiotic treatment (0.025% tetracycline) was introduced 
to the food. Flies cultured on this substrate were less productive and 
pupated faster than those on normal food. The offspring of the treated 
generation survived normally for one generation. Unfortunately, the 
following generation again displayed the same symptoms of mass mortality 
at 5 days old.

I have contacted companies that can identify microorganisms and suggest 
treatments but they were not able to respond our queries.



I would be really grateful if anyone has any suggestions on other 
procedures that I could undertake or who to contact who would be able to 
suggest solutions to determine the problem.

Thanks!





Nelly Gidaszewski

Research associate

Department of Animal and Plant Sciences

University of Sheffield

UK



email: n.gidaszewski from sheffield.ac.uk


 




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