Radiation resistance of actinomycetes inhibiting different Egyptian soil
1985
El-Zawahry, Y.A. (Zagazig Univ. (Egypt). Faculty of Science) | Dewedar, A. | Sweiha, H.E.
The count of actinomycetes in different soil samples increased with increasing doses of gamma irradiation. The lethal doses for the actinomycetes isolated from references soil samples ranged from 10 KGY for sandy soil (sample D) to 25 KGY for cultivated tomato rhizosphere (soil sample E). The most irradiation resistant actinomycetes isolated at sublethal irradiation doses were identified as: Microellobosporia flavea (E, 20 KGY); Microellobosporia violacea (3, 20 KGY); Micropolyspora rubrobrusa (C, 18 KGY); Spirillospora albida (A, 15 KGY); Streptomyces albidofuscus (B, l9 KGY), (D, 9 KGY) and (E, 2o KGY); Streptomyces albus (E, 20 KGY); and Streptomyces luteofluorescans (A, 15 KGY) and (S, 20 KGY). The highest D10-value (dose required to reduce number of population by 90%) is equal to 4.5 KGY for Streptomyces albidofuscus (B, 19 KGY) with the highest shoulder value of 3.2 KGY. On the other hand, the lowest D10-value was recorded for Streptomyces luteofluorescens (S, 20 KGY) and found to be 1.4 KGY showing straight line dose response curve. The most radioresistant isolates do not show antimicrobial activity against the tested organisms and do not produce any of the aflatoxins.
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