Bacillus thuringiensis

Natasa Pasic-Knezevic natasa at yorku.ca
Mon Mar 4 22:23:26 EST 1996


Al <Yousten at vt.edu> wrote:

>We need a bit more information i..e. are you asking about viability of 
>the spores or about the effectiveness of the toxins (in the parasporal 
>body). And are you concerned about residual effectiveness on plant 
>leaves or in the water (Bti against mosquitoes)? Of course, the 
>companies that have been producing Bt for the past 40 years or so have 
>been interested in these questions and have attempted to prolong 
>effectiveness. There are a number of papers, particularly in the older 
>literature, concerning things like UV inactivation of toxins but I don't 
>know of any phys/chem  studies of the effects on the proteins 
>themselves. The answer to your question may depend on the depth to which 
>you are pursuing the question.

O.K. I'll explain what I mean.

I have read in a few  papers that B. thuringiensis is extremely
sensitive to environmental conditions. Although it is a soil
bacterium, it is quite difficult to isolate it from the soil (does it
mean that it is present only in a small quantity?). Couple of times I
failed to isolate it from soils that were supposed to support its
growth.

I am mostly interested in DNA repair in B. thuringiensis. Some DNA
repair mechanisms - SOS (or SOB if you want) are found to be inhibited
in toxin-producing subspecies. So, what I am interested in is whether
or not this sensitiveness to environmental conditions might be due to
failure of some DNA repair functions in B. thuringiensis.

Thanks for response.

Ivan







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