تطوير نظام بكتري لتحديد المطفرات في البيئة و الأغذية : أولا : التطفير بالمطفر القياسي Nitrosogunanidine

الملخص EN

Three soil isolates were selected lo devclope mutagenicity test system.

They were G3 belongs lo Bacillus spp ; G12 belongs to Arthrobactcr ; G27 belongs lo Brcvibactcrium .

They were sensitive to streptomycin and rifampicin .

The isolates were tested for their sensitivity lo crystal violet, G3 was.

the most sensitive isolate .

Mutagen N- methyl -N - nilro N nilrosoganidinc ( NTG) used lo mutagcnizc these isolates and using streptomycin and rifampicin resistance as a chromosomal markers .

NTG treatment caused reduction in viable count of isolates al different levels .

The treatment also led to induction of streptomycin and rifampicin resistant mutants, in one case the treatment led to induction of double mutant ( i.e.

, resistant lo streptomycin and rifampicin al ihe same time) in G27 isolate only.

Dose- response of mutation frequency was observed as an increasing in mutant frequency with increasing mutagen concentration Comparison of relative mutability ( Rml) of isolates was carried out and G12 exhibited the highest Rml and this extended when calculating the relative mutational sensitivity ( Rm.s ).