Premium
Stimulation of nitrogenase activity and photosynthesis in some cyanobacteria by glyoxylate
Author(s) -
BERGMAN B.
Publication year - 1980
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1980.tb03324.x
Subject(s) - glyoxylate cycle , nitrogenase , photosynthesis , dcmu , cyanobacteria , darkness , stimulation , biology , biochemistry , chemistry , nitrogen fixation , metabolism , botany , bacteria , photosystem ii , endocrinology , genetics
The effect og glyoxylate on nitrogenase activity (C 2 H 2 reduction) and photosynthesis (H 14 CO 3 fixation and O 2 evolution) was in vestigated in the three heterocystous cyanobacteria Anabaena cylindrica, A. variabiltis and N. muscorum. Glyoxylate had virtually no effect on the rate of dark respiration and was unable to sustain photoheterotrophic growth, though some slight stimulation (= 30%) of photorophic growth was noted. A considerable stimulation of both nitrogenase and photosynthetic activities was observed in presence of glyoxylate. In the light the stimulation increased with time up to about 15‐25 h after adding optimal concentrations of 4–6 m M glyoxylate. Placing glyoxylate treated samples in the dark or adding DCMU (30 μ M ) in the light, showed that glyoxylate initially supported significantly higher nitrogenase activity than did samples in absence of glyoxylate. However, after a prolonged incubation in the dark or in presence of DCMU glyoxylate is unable to relieve the adverse effects of such conditions. The stimulation of the nitrogenase activity was even more pronounced when the glyoxylate was added to cells preincubated in the dark (“carbon starved”) than for cells kept constantly in light. The results suggest that glyoxylate, or a metabolite, may act as an inhibitor of cyanobacterial photorespiration and this hypothesis is discussed.