petites in yeasts - (Sep/04/2012 )

Anybody work with petites (respiratory deficient mutants) of yeasts? I suddenly noticed some petite like colonies and what could be the easiest and reliable way to characterize them?

Saccharomyces cerevisiae petites have no or non-functional mitochondria and require an external souce of some lipids for extended growth. As I recall, petite cells do not reduce TTC (triphenyl tetrazolium) in the presence of glucose to a red color while respiratory competent cells do.