Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae

1970 ◽  
Vol 74 (3) ◽  
pp. 235-243 ◽  
Author(s):  
A. Haystead ◽  
R. Robinson ◽  
W. D. P. Stewart
Keyword(s):  
Green Algae ◽  
Nitrogenase Activity ◽  
Blue Green Algae

Nitrogenase Activity in Heterocysts of Blue–Green Algae

Nature ◽  
1969 ◽  
Vol 224 (5216) ◽  
pp. 226-228 ◽  
Author(s):  
W. D. P. STEWART ◽  
A. HAYSTEAD ◽  
H. W. PEARSON
Keyword(s):  
Green Algae ◽  
Nitrogenase Activity ◽  
Blue Green Algae

Nitrogenase activity, amino acid pool patterns and amination in blue-green algae

Planta ◽  
1972 ◽  
Vol 108 (2) ◽  
pp. 133-145 ◽  
Author(s):  
M. W. N. Dharmawardene ◽  
W. D. P. Stewart ◽  
S. O. Stanley
Keyword(s):  
Amino Acid ◽  
Green Algae ◽  
Nitrogenase Activity ◽  
Amino Acid Pool ◽  
Blue Green Algae ◽  
Acid Pool

Effects of aerobic and anaerobic conditions on growth and metabolism of blue-green algae

1970 ◽  
Vol 175 (1040) ◽  
pp. 293-311 ◽  
Keyword(s):  
Photosystem Ii ◽  
Green Algae ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Electron Flow ◽  
Reducing Power ◽  
Nostoc Muscorum ◽  
Blue Green Algae ◽  
Reducing Conditions ◽  
Ph Range

The blue-green algae Anabaena flos-aquae and Nostoc muscorum may reduce acetylene to ethylene most actively at p O 2 levels below 0.2 atm. High p O 2 levels inhibit acetylene reduction, nitrogen fixation, respiration and 14 CO 2 fixation in A . flos-aquae . The effect is not solely via an inhibition of nitrogenase activity because inhibition of 14 CO 2 fixation by a species of Phormidium which does not fix nitrogen, and by A . flos-aquae grown on combined nitrogen also occurs. The inhibition of acetylene reduction in Anabaena is reversible in short-term experiments, the rate of recovery being rather similar irrespective of the p O 2 level to which the alga was subjected initially. 3(3,4-dichlorophenyl)-1-1-dimethyl urea (DCMU) at a concentration of 3 x 10 -5 M, which completely inhibits oxygen evolution and acetylene reduction but not respiration by aerobically grown Anabaena cultures also inhibits acetylene reduction in Na 2 S-grown cultures. Salicylaldoxime at a concentration of 10 -4 M which partially inhibits electron flow from photosystem II inhibits acetylene reduction to a greater extent under aerobic conditions than in the presence of Na 2 S. The presence of Na 2 S also results in the removal of free oxygen from the medium in the pH range at which Anabaena normally grows. The data suggest that under our conditions (1) the photolysis of water, or photosystem II is essential for the growth of A. flos-aquae in the presence of H 2 S ; (2) H 2 S may provide electrons when reducing power from the photolysis of water is reduced but not inhibited completely; (3) H 2 S prevents an accumulation of oxygen in the medium during photosynthesis. These physiological findings from the laboratory may help to explain why blue-green algae live not only in aerobic environments but also in habitats where reducing conditions may prevail.

Characteristics of nitrogenase activity in broken cell preparations of the blue-green alga Gloeocapsa sp. LB 795

1972 ◽  
Vol 18 (3) ◽  
pp. 327-332 ◽  
Author(s):  
J. R. Gallon ◽  
T. A. Larue ◽  
W. G. W. Kurz
Keyword(s):  
Adenosine Triphosphate ◽  
Green Algae ◽  
Green Alga ◽  
Enzyme System ◽  
Nitrogenase Activity ◽  
Adenosine Diphosphate ◽  
Sodium Dithionite ◽  
Kinetic Properties ◽  
Blue Green Alga ◽  
Blue Green Algae

Broken cell preparations of the blue-green alga Gloeocapsa sp. LB 795 reduce acetylene to ethylene and evolve hydrogen in the presence of sodium dithionite and adenosine triphosphate (ATP). The enzyme system is almost completely inhibited by adenosine diphosphate (ADP) (7.5 mM), O2 and CO (0.01 atm), and CO2 (0.05 atm). Its kinetic properties are very similar to those of nitrogenases from other sources, but, unlike the enzymes so far isolated from other blue-green algae, Gloeocapsa nitrogenase is sedimented by centrifugation at 10 000 g.

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