Isolation of Mutants Resistant to some Chemicals from Sunlight –Exposed and Unexposed Samples of the Fungus Alternaria alternata

W.  Hadi, Huda

doi:10.33899/rjs.2017.138938

	Isolation of Mutants Resistant to some Chemicals from Sunlight –Exposed and Unexposed Samples of the Fungus Alternaria alternata
Rafidain Journal of Science
Article 8, Volume 26, Issue 2, 2017, Pages 74-85 PDF (0 K)
DOI: 10.33899/rjs.2017.138938
Author
Huda W. Hadi
Abstract
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.
Keywords
Alternaria Alternata; resistant mutants; Sunlight; cross resistance; chemicals

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