[Yeast] Problem with -His plates

[Anna Heidenblut]

Dear list,

I'm new to working with yeast and I've got trouble with my -His plates:

I've prepared to batches of -His plates using batches of CSM-His from 
two different labs and adding glucose (Fisher Scientific), N-base 
(ForMedium) and bacto-agar (BD). I've plated His- strains (which are 
definitely OK) on these plates and they grow on both batches of plates. 
I restreaked the yeast to the -His plates to make sure they don't carry 
over too much His from the YPD they were grown in but they still grow 
when restreaked on -His plates.

Has anybody ever experienced problems with His contamination of glucose, 
N-base or bacto-agar?

Thank you for your help.

Anna

-- 
Dr. Anna Heidenblut (PhD)

Genome Integrity Group
Department of Molecular Oncology
Weatherall Institute of Molecular Medicine
Oxford University John Radcliffe Hospital,
Headley Way, Oxford, Oxfordshire OX3 9DS UK
Tel: 0044 / 1865 / 222419