Actually, you are off by about a decade. Among others, Iyer and
Szybalski (Applied Microbiology 6:23-29, 1958) detected chemical
mutagens using the E. coli streptomycin dependence system developed by
Bertani (Genetics 36:598-611, 1951). The late Vernon Bryson, one of
my professors, once suggested that this test could have been as
widely-practiced as the Salmonella/Ames test had they utilized
permeability mutations, DNA repair defects and metabolic activation
systems that were incorporated in the Salmonella system 20 years
later. Given that Bacillus is naturally more permeable to chemicals
than E. coli, it might be interesting to develop it as a mutagenicity
test. SWM
Mamber at synapse.bms.com
>>Hi there,
I think the first reports about streptomycin resistance and dependence
appeared in the 1960's (look out for reviews by Luigi Gorini).
In E. coli streptomycin dependence is caused by certain mutations in the
gene rpsL (which codes for ribosomal protein S12). These mutations often
lead to an increased accuracy and decreased efficiency of translation.
A strong decrease in efficiency can result in a reduction of the maximal
bacterial growth rate. (Does your mutant grow slower?) There is an
extensive literature available about E. coli rpsL mutants that cause
streptomycin resistance or dependence (Advice: in the older literature
they are called strA mutations...). I know that in other bacteria, as
Mycobacteria tuberculosis, streptomycin resistance is also caused by
alterations of S12, and I guess that the same holds true for Bacillus.
If you want some literature references conntact me by:
redaschi at ubaclu.unibas.ch<<
