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Title: Regulation of nitrate reductase (NR) synthesis investigated by using mutants of Chl. sorokiniana partially NR deficient

Abstract

After X-ray irradiation 13 NR and 8 nitrite reductase (NiR) deficient mutants of Chl.sorokiniana were obtained. In order to assure best experimental conditions for the characterization of the NR mutants, for which NO/sub 3//sup -/-containing medium in fact is a N-medium, they transferred wild type cells from NH/sub 4//sup +/ to NO/sub 3//sup -/ or N-medium, respectively. It turned out, that NO/sub 3//sup -/ is not necessary for starting de-novo-synthesis of NR. Therefore NR in Chlorella is a derepressible enzyme rather than an inducible one. Maximum amount of NR is present 80 min. after transfer of cells. Derepression experiments with the mutant strains characterized 3 of them as defect in Mo-co subunit of NR with best cytochrome c reductase (CCR)-activity, although xanthine oxidase (XO) was inducible. One other mutant is CCR-defect but contains intact Mo-co. The latter strain produced 4-6 times more Mo-co than the wild type, giving some evidence for an unbalanced self-regulation of NR-synthesis. Another strain lacked XO-activity, indicating a common cofactor among XO and NR as reported for other organisms.

Authors:
;
Publication Date:
Research Org.:
Universitaet of Goettingen, West Germany
OSTI Identifier:
5331962
Resource Type:
Conference
Journal Name:
Plant Physiol., Suppl.; (United States)
Additional Journal Information:
Journal Volume: 80:4; Conference: Annual meeting of the American Society of Plant Physiologists, Baton Rouge, LA, USA, 8-12 Jun 1986
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CHLORELLA; MUTANTS; NITRATES; REDUCTION; OXIDOREDUCTASES; SYNTHESIS; ENZYME INDUCTION; ENZYMES; GENE REPRESSORS; ALGAE; CHEMICAL REACTIONS; GENE REGULATION; MICROORGANISMS; NITROGEN COMPOUNDS; NUCLEOPROTEINS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; PLANTS; PROTEINS; UNICELLULAR ALGAE; 550400* - Genetics

Citation Formats

Knobloch, O, and Tischner, R. Regulation of nitrate reductase (NR) synthesis investigated by using mutants of Chl. sorokiniana partially NR deficient. United States: N. p., 1986. Web.
Knobloch, O, & Tischner, R. Regulation of nitrate reductase (NR) synthesis investigated by using mutants of Chl. sorokiniana partially NR deficient. United States.
Knobloch, O, and Tischner, R. 1986. "Regulation of nitrate reductase (NR) synthesis investigated by using mutants of Chl. sorokiniana partially NR deficient". United States.
@article{osti_5331962,
title = {Regulation of nitrate reductase (NR) synthesis investigated by using mutants of Chl. sorokiniana partially NR deficient},
author = {Knobloch, O and Tischner, R},
abstractNote = {After X-ray irradiation 13 NR and 8 nitrite reductase (NiR) deficient mutants of Chl.sorokiniana were obtained. In order to assure best experimental conditions for the characterization of the NR mutants, for which NO/sub 3//sup -/-containing medium in fact is a N-medium, they transferred wild type cells from NH/sub 4//sup +/ to NO/sub 3//sup -/ or N-medium, respectively. It turned out, that NO/sub 3//sup -/ is not necessary for starting de-novo-synthesis of NR. Therefore NR in Chlorella is a derepressible enzyme rather than an inducible one. Maximum amount of NR is present 80 min. after transfer of cells. Derepression experiments with the mutant strains characterized 3 of them as defect in Mo-co subunit of NR with best cytochrome c reductase (CCR)-activity, although xanthine oxidase (XO) was inducible. One other mutant is CCR-defect but contains intact Mo-co. The latter strain produced 4-6 times more Mo-co than the wild type, giving some evidence for an unbalanced self-regulation of NR-synthesis. Another strain lacked XO-activity, indicating a common cofactor among XO and NR as reported for other organisms.},
doi = {},
url = {https://www.osti.gov/biblio/5331962}, journal = {Plant Physiol., Suppl.; (United States)},
number = ,
volume = 80:4,
place = {United States},
year = {Tue Apr 01 00:00:00 EST 1986},
month = {Tue Apr 01 00:00:00 EST 1986}
}

Conference:
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