In article <30CCB9D5.4EAC at medcor.mcgill.ca>, Greg Cosentino
<Cosentino at medcor.mcgill.ca> wrote:
> Hi Netters,
>> I am checking the ability of a yeast strain to grow on
> non-fermentable carbohydrates (glycerol, ethanol, and acetate)
> compared to glucose. As a lark, I also streaked my yeast onto
> control plates composed of yeast extract and peptone but with no
> carbohydrate at all. It seems that the strains capable of aerobic
> growth also grew in the absence of any carbohydrate whatsover, but
> the petite mutants didn't grow. The seed cultures were made in
> liquid YPD media and then washed extensively with water prior to
> plating so I wouldn't carry over any of the glucose containing media
> when I plated them. Any ideas to explain growth of the yeast in the
> absence of carbohydrate?
They should not grow. I tend to think, that there are residual amounts of
sugars in your agar. I tried to grow wildtype yeast (S.c) in liquid YPD
where I by mistake did not add glucose or any other carbon source, and i
have got definitely NO growth.
On the other hand, for some yeast the carbon skeletons coming from the
degradation of amino acids might be enough to feed Krebs cycle to produce
enough NADH for respiratory chain.
Tomas Drgon
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