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A cyanobacterial mutant resistant against a bleaching herbicide
Author(s) -
Vaishampayan A.,
Sinha R.P.,
Gupta A.K.,
Häder D.P.
Publication year - 2000
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/1521-4028(200008)40:4<279::aid-jobm279>3.0.co;2-e
Subject(s) - photophosphorylation , methylamine , nitrogenase , cyanobacteria , mutant , biochemistry , strain (injury) , photosynthesis , axenic , atp synthase , chemistry , biology , nitrogen , nitrogen fixation , bacteria , enzyme , chloroplast , genetics , anatomy , gene , organic chemistry
The nitrogen fixing cyanobacterium Nostoc muscorum has been found to be sensitive to the herbicide SAN 6706 [4‐chloro‐5 (dimethylamino)‐2‐(a,a,a,‐trifluoro‐m‐tolyl)‐3‐(2H) pyridazinon] at 30–45 μ M within 15 min. The toxicity was more severe in combined nitrogen‐free (N comb ‐free) medium than in a combined nitrogen medium; this enhancement was reversible by supplementation of the medium with 3 mM glucose or 5 μ M ATP, serving as carbon and/or energy source in this organism. A mutant of this cyanobacterium resistant to 3 m M SAN 6706 has been isolated and characterized to perform nitrogenase activity in exogenous ATP supplemented N comb ‐free medium. However, it exhibited a moderate growth in combined nitrogen media in the absence of external ATP. The resistance factor is higher than 100. Simultaneously, this strain possesses a cross‐resistance to methylamine, a well‐known inhibitor of photophosphorylation, irrespective of the exogenous ATP supply. The behavior of the mutant suggests a defective phosphorylation in its photosynthetic system.