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Genetic studies on a nitrogen-fixing cyanobacterium. [Anabaena; Escherichi coli]

Conference · · Plant Physiol., Suppl.; (United States)
OSTI ID:6064448

Mutants of Anabaena PCC7120 capable of aerobic growth with NO/sub 3//sup -/ but not N/sub 2/, and capable of microaerobic reduction of C/sub 2/H/sub 2/, were isolated by penicillin enrichment after UV irradiation. Heterocysts of two mutants lack the principal envelope glycolipid, those of EF116 have a non-cohesive envelope polysaccharide, and those of other strains have other defects. A Nm/sup r/ cosmid library of DNA from wild type Anabaena PCC7120 was established in Escherichia coli bearing the Ap helper plasmid pDS4101. A conjugative plasmid was introduced, and the bacteria replicated to lawns of individual mutant strains of Anabaena. After one day of non-selective growth, selection was applied for Nm/sup r/ and nitrogen fixation. Overlapping cosmids complementing EF116 and one complementing another mutant have been mapped. The complementing genes are thought to act early in differentiation. Inclusion, in an E. coli donor of an appropriate methylase gene enhanced, by a factor of 10/sup 2/ to 10/sup 3/, transfer to Anabaena PCC7120 of a plasmid containing numerous sites for the Anabaena restriction endonuclease, AvaII.

Research Organization:
Michigan State Univ., East Lansing
OSTI ID:
6064448
Report Number(s):
CONF-8707108-
Journal Information:
Plant Physiol., Suppl.; (United States), Journal Name: Plant Physiol., Suppl.; (United States) Vol. 83:4; ISSN PPYSA
Country of Publication:
United States
Language:
English