Factor C-LHIH which inhibits the luteinizing hormone from basal release and from synthetic LHRH and studies on purification of FSHRH |
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Authors: | K Nils-Gunnar Johansson Tyge Greibrokk Bruce L Currie Jan Hansen Karl Folkers Cyril Y Bowers |
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Institution: | Institute for Biomedical Research The University of Texas at Austin Austin, Texas 78712, USA;Tulane University, School of Medicine New Orleans, Louisiana 70112, USA |
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Abstract: | Mutants of the nitrogen-fixing blue-green alga Nostocmuscorum have been isolated which do not fix nitrogen or reduce acetylene, and which are resistant to streptomycin (1000 μg ml?1). One such mutant (nif-st-R) was crossed with the wild-type nitrogen-fixing streptomycin-sensitive parent (nif+st-S) and under conditions which counterselected the latter, recombinants (nif+st-R) were obtained at a frequency of up to 4.6 in 105 colonies. The frequency of spontaneous mutations or revertants of each parent growing alone was 1 in 107 or less. The higher yield of new genotypes from mixed cultures is interpreted as evidence of nif gene transfer in Nostocmuscorum. |
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