scholarly journals The effects of acetaldehyde on nitrogenase, hydrogenase and photosynthesis in the cyanobacterium Anabaena cylindrica

1983 ◽  
Vol 212 (3) ◽  
pp. 755-758 ◽  
Author(s):  
B Slatyer ◽  
A Daday ◽  
G D Smith
Keyword(s):  
Methyl Viologen ◽  
Co2 Fixation ◽  
Electron Flow ◽  
Anabaena Cylindrica ◽  
O2 Uptake ◽  
Irreversible Inhibitor ◽  
Photosynthetic Electron Flow ◽  
Separate Electron ◽  
Cyanobacterium Anabaena ◽  
Flow Through

Acetaldehyde was shown to be an irreversible inhibitor of nitrogenase, hydrogenase, CO2 fixation and growth in the cyanobacterium Anabaena cylindrica, but had no effect on photosynthetic electron flow as measured by Methyl Viologen-dependent O2 uptake. The concentration-dependence of the inhibition of nitrogenase and hydrogenase activities was determined, and it was shown that acetaldehyde inhibition poses problems for anaerobic experiments in which the activities of these enzymes are measured in the presence of the frequently used glucose/glucose oxidase/catalase/ethanol O2 trap. It is suggested that acetaldehyde may find use as an inhibitor in experiments designed to separate electron flow through the photosystems from consequent fixation of CO2 and N2.

CO2 Fixation in Anabaena cylindrica

1982 ◽  
Vol 37 (3-4) ◽  
pp. 213-217 ◽  
Author(s):  
Günter Döhler
Keyword(s):  
Co2 Fixation ◽  
Calvin Cycle ◽  
Total Radioactivity ◽  
Nitrogen Atmosphere ◽  
Anabaena Cylindrica ◽  
Dark Light ◽  
Initial Fixation ◽  
Phosphoglyceric Acid ◽  
Cyanobacterium Anabaena ◽  
Glycolate Metabolism

Abstract The cyanobacterium Anabaena cylindrica grown in a nitrogen -free medium at + 25 °C was used for short-term 14C-kinetics experiments under different conditions. During the dark/light transients the initial fixation products were mainly sugar monophosphates and 3-phosphoglyceric acid (Calvin cycle intermediates), aspartate (10% of total radioactivity) and glycine/serine. Io­ doacetamide (0.01 м) caused an inhibition o f photosynthetic 14CO2 fixation and a 14C-in corpor­ation into aspartate, glutamate and 3-phosphoglyceric acid only. During dark 14CO2 assimilation labelling of these products could be measured, too. In a nitrogen atmosphere (N2 + 0.04 vol. % CO2) a strong labelling of sugar monophosphates mainly at the beginning o f photosynthetic period could be observed. In an oxygen atmosphere (100% O2) an enhanced label of aspartate and glycerate and a decreased radioactivity in sugar monophosphates were found. Our results were discussed with reference to the operating of a phosphoenolpyruvate carboxylation reaction be­ sides the Calvin cycle and to the glycolate metabolism.

scholarly journals Limited photosynthetic electron flow but no CO2 fixation in Chlamydomonas mutants lacking photosystem I

FEBS Letters ◽  
1997 ◽  
Vol 416 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Laurent Cournac ◽  
Kevin Redding ◽  
Pierre Bennoun ◽  
Gilles Peltier
Keyword(s):  
Photosystem I ◽  
Co2 Fixation ◽  
Electron Flow ◽  
Photosynthetic Electron Flow ◽  
Chlamydomonas Mutants

scholarly journals Electron flow through NDH-1 complexes is the major driver of cyclic electron flow-dependent proton pumping in cyanobacteria

2020 ◽  
Author(s):  
Neil T. Miller ◽  
Michael D. Vaughn ◽  
Robert L. Burnap
Keyword(s):  
Electron Flow ◽  
Proton Pumping ◽  
Cyclic Electron Flow ◽  
Pumping Rate ◽  
Photosynthetic Organisms ◽  
Photosynthetic Electron Flow ◽  
Flow Through ◽  
Pumping Rates ◽  
Kinetics Of

AbstractCyclic electron flow (CEF) around Photosystem I is vital to balancing the photosynthetic energy budget of cyanobacteria and other photosynthetic organisms. The coupling of CEF to proton pumping has long been hypothesized to occur, providing proton motive force (PMF) for the synthesis of ATP with no net cost to [NADPH]. This is thought to occur largely through the activity of NDH-1 complexes, of which cyanobacteria have four with different activities. While a much work has been done to understand the steady-state PMF in both the light and dark, and fluorescent probes have been developed to observe these fluxes in vivo, little has been done to understand the kinetics of these fluxes, particularly with regard to NDH-1 complexes. To monitor the kinetics of proton pumping in Synechocystis sp. PCC 6803, the pH sensitive dye Acridine Orange was used alongside a suite of inhibitors in order to observe light-dependent proton pumping. The assay was demonstrated to measure photosynthetically driven proton pumping and used to measure the rates of proton pumping unimpeded by dark ΔpH. Here, the cyanobacterial NDH-1 complexes are shown to pump a sizable portion of proton flux when CEF-driven and LEF-driven proton pumping rates are observed and compared in mutants lacking some or all NDH-1 complexes. It is also demonstrated that PSII and LEF are responsible for the bulk of light induced proton pumping, though CEF and NDH-1 are capable of generating ∼40% of the proton pumping rate when LEF is inactivated.Highlights statementNDH-1 is essential for proton pumping during cyclic photosynthetic electron flow in cyanobacteria

scholarly journals The pathways of assimilation of 13NH4+ by the cyanobacterium, Anabaena cylindrica.

1977 ◽  
Vol 252 (21) ◽  
pp. 7894-7900
Author(s):  
J.C. Meeks ◽  
C.P. Wolk ◽  
J. Thomas ◽  
W. Lockau ◽  
P.W. Shaffer ◽  
...  
Keyword(s):  
Anabaena Cylindrica ◽  
Cyanobacterium Anabaena

Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 374-377 ◽  
Author(s):  
J. J. S. van Rensen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
Amaranthus Hybridus ◽  
Apparent Affinity ◽  
Photosynthetic Electron Flow ◽  
Different Characteristics ◽  
The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

Non-Invasive Monitoring of the Light-Induced Cyclic Photosynthetic Electron Flow during Cold Hardening in Wheat Leaves

2006 ◽  
Vol 61 (9-10) ◽  
pp. 734-740 ◽  
Author(s):  
Simona Apostol ◽  
Gabriella Szalai ◽  
László Sujbert ◽  
Losanka P. Popova ◽  
Tibor Janda
Keyword(s):  
Winter Wheat ◽  
Electron Flow ◽  
Wheat Variety ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Light Conditions ◽  
Non Invasive ◽  
Photosynthetic Electron Flow ◽  
Temperature Hardening ◽  
Wheat Leaves

AbstractThe effect of irradiance during low temperature hardening was studied in a winter wheat variety. Ten-day-old winter wheat plants were cold-hardened at 5 °C for 11 days under light (250 μmol m-2 s-1) or dark (20 μmol m-2 s-1) conditions. The effectiveness of hardening was significantly lower in the dark, in spite of a slight decrease in the Fv/Fm chlorophyll fluorescence induction parameter, indicating the occurrence of photoinhibition during the hardening period in the light. Hardening in the light caused a downshift in the far-red induced AG (afterglow) thermoluminescence band. The faster dark re-reduction of P700+, monitored by 820-nm absorbance, could also be observed in these plants. These results suggest that the induction of cyclic photosynthetic electron flow may also contribute to the advantage of frost hardening under light conditions in wheat plants.

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