عزل بعض الطافرات المقاومة لبعض المواد الكيمياوية من عينات كونيدية معرضة لأشعة الشمس و عينات غير معرضة من الفطر Alternaria alternate

Abstract EN

A total of 272 mutants (161 from sunlight exposed and 111 from unexposed conidia) resistant to the chemicals Topas, 8-azaguanine or Chloral hydrate were Isolated in the fungus Alternaria alternata.

Initially, the exposure periods to sunlight and the minimal inhibitory concentrations for the chemicals were determined.

The exposure periods were 20, 40, 60 and 90 minutes and the minimal inhibitory concentrations were 150 μg / ml for Topas, 3.5 μg / ml for 8-azaguanine and 4.5 mM for Chloral hydrate.

The frequency of mutants resistant to each chemical was calculated and although the frequencies from the exposed samples were greater than those from unexposed one, the differences, however, were statistically not significant pointing to the weakness of mutagenicity of the sunlight in the present experimental protocol.

Cross resistance exhibited by any of the three classes of resistant mutants to other two chemicals was also tested.

A fraction of 93.2 % of the Topas resistant mutant cross resisted 8-azaguanine as well, and 83 % of them cross resisted Chloral hydrate.

Azaguanine resistant mutants and Chloral hydrate resistant mutants, however, exhibited very low cross resistance to those two chemicals, being no more than 4 % as its higher proportion.