كليدواژه :
مقاومت به ريفامپين , E. coli , BACILLUS THURINGIENSIS , موتاسيون , باكتري انرژي نور ماورا بنفش
چكيده لاتين :
In order to investigate the effect of UV-irradition on motality of spore vegetative and producing bacterium and fungis, various doses of UV-irradiation was applied. Optimum dose of UV-C irradiation on mutation induction in bacteria, as well as effect of various shields on UV-blockage, was investigated. The Escherichia coli and Bacillus thuringiensis bacteria exposed to various doses of 254 nm. UV radiation Effects of lowest doses, (11 J/m2), and highest doses of UV irradiation on survival of bacterial cells evaluated. B. thuringiensis compare to that of E. coli, exhibited high level of tolerance against the UV irradiation. 200 J/m2 of UV irradiation did not have adverse effect on B. thuringiensis, however, survival cells of the bacterium decreased from 260 J/m2, and number of survival cells fall bellow Logl at 3000J/m2. In E. coli, UV irradiation dose of 170 J/m2, decreased number of survival cells up to 51og. Spores and micellium of penicillium fungi, in compare to those of the bacteria, showed a high level of tolerance to UV irradiation. At 18000 J/m2, few survival colonies of the fungi observed on solid medium. The effect of various shields on penetration of UV was investigated. Anti - UV Low Density Poly Ethylene (LDPE) and 1mm thick glass, completely prevented penetration of UV beam. However, ordinary LDPE shields, having various thickness, did not have significaut effect on penetration j of UV beam. In this relation, 6Ml LDPE did not have effect on penetration of UV beam. 88 J/m2 UV irradiation caused mutation on E. coli bacterium and rifampin resistant colonies achieved. However, 480 J/m2 UV irradiation did not produce mutated B. thuringiensis cells, with characteristic of disable to produce bacterial spores.
