Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/19106
Title: Immobilization caused physiological and biochemical changes in NaCl-resistant (NaClr) mutant strain of diazotrophic cyanobacterium Anabaena variabilis
Authors: Chauhan, V S
Singh, S
Gour, R K
Bisen, P S
Issue Date: Jul-1999
Publisher: NISCAIR-CSIR, India
Abstract: Growth (in term of μ and G), heterocyst differentiation, nitrogenase activity, ammonia production, ammonia uptake, glutamine synthetase (GS) activity, 14CO2 -fixation and Hill activity have been studied in the wild-type Anabaena variabilis and its NaCl-resistant (NaClr) mutant strain immobilized in calcium alginate gel. NaClr mutant strain grew well both in the presence as well as absence of NaCl (300 mM) at a rate similar to its wild-type strain in NaCl-free medium. Further, NaClr mutant strain had generation time of 33.3 and 71.4 hr, respectively in its free-living and immobilized conditions. Immobilization of the cells in calcium alginate gel increased heterocyst differentiation and nitrogenase activity in both wildtype and its NaClr strain. GS activity in NaClr mutant strain was altered by mutation causing liberation of ammonia in the external medium. No detectable ammonia was however, liberated by the free-living and immobilized wild-type strain. NaCl (300 mM) significantly inhibited the growth, heterocyst differentiation, nitrogenase activity, ammonia uptake, GS activity, carbon-fixation and Hill activity in the wild-type strain, whereas these activities were stimulated in NaClr mutant strain. Further immobilization of NaClr mutant strain whereas caused decrease in ammonium uptake and GS acti vity, it stimulated carbon-fixation and Hill activity in this strain. Thus it is suggested that increased ammonium photoproduction by immobilized NaClr mutant strain was due to decrease in ammonium uptake, GS activity and susceptibility of nitrogenase to repression by ammonia and subsequent increase in heterocyst differentiation, nitrogenase activity, carbon-fixation and Hill activity.
Page(s): 696-700
URI: http://hdl.handle.net/123456789/19106
ISSN: 0975-1009 (Online); 0019-5189 (Print)
Appears in Collections:IJEB Vol.37(07) [July 1999]

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