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

Conference · Tue Apr 01 00:00:00 EST 1986 · Plant Physiol., Suppl.; (United States)

OSTI ID:5331962

Knobloch, O; Tischner, R

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.

• Research Organization: Universitaet of Goettingen, West Germany
• OSTI ID: 5331962
• Journal Information: Plant Physiol., Suppl.; (United States), Vol. 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

Related Subjects

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