Feb 22, 1974

Photosynthetic regulation by cations in spinach chloroplasts

Biochimica Et Biophysica Acta
T V Marsho, B Kok

Abstract

(1) In the presence of > or =3 mM divalent cations or > or =100 mM monovalent cations, weak 650-nm light, presumably containing an excess of Photosystem II quanta, caused substantial reduction of the electron carrier pool between the two photoacts. In low-salt media, most electron carriers were oxidized during red light. (2) In the presence of low concentrations of carbonylcyanide m-chlorophenylhydrazone (CCCP) (0.3 microM) or antimycin A (40 microM) the pool remained oxidized even in the presence of adequate cation concentrations. (3) The non-linear dependence of the O2-evolution rate upon the concentration of active Photosystem II trapping centers, which implies energy transfer between Photosystem II units, was observed only in the presence of sufficient cation. (4) Enhancement of the rate of methyl viologen reduction in far-red light by red light was found to be a weak function of Mg2+ concentration. (5) With ferredoxin-NADP+ as acceptor, enhancement of the rate of O2 evolution in 650-nm light by far-red light was obtained only with added Mg2+. Furthermore, Mg2+ addition markedly stimulated the quantum yields of NADP+ reduction, independent of wavelength, with either water or ascorbate-reduced 2,6-dichlorophenolindophenol (D...Continue Reading

Mentioned in this Paper

Spinach preparation
Cations, Divalent
Ferredoxin
Energy Transfer
2,6-Dichloroindophenol
Uncoupling Agents
Spinacia oleracea
Antimycin A
Ferredoxin Activity
Carbonyl Cyanide m-Chlorophenyl Hydrazone

About this Paper

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

Head And Neck Squamous Cell Carcinoma

Squamous cell carcinomas account for >90% of all tumors in the head and neck region. Head and neck squamous cell carcinoma incidence has increased dramatically recently with little improvement in patient outcomes. Here is the latest research on this aggressive malignancy.

Signaling in Adult Neurogenesis

Neural stem cells play a critical role in the production of neuronal cells in neurogenesis is of great importance. Of interest is the role signalling mechanisms in adult neurogenesis. Discover the latest research on signalling in adult neurogenesis.

Psychiatric Chronotherapy

Psychiatric Chronotherapy considers the circadian rhythm as a major factor for optimizing therapeutic efficacy of psychiatric interventions. Discover the latest research on Psychiatric Chronotherapy here.

Bone Marrow Neoplasms

Bone Marrow Neoplasms are cancers that occur in the bone marrow. Discover the latest research on Bone Marrow Neoplasms here.

IGA Glomerulonephritis

IgA glomerulonephritis is a chronic form of glomerulonephritis characterized by deposits of predominantly Iimmunoglobin A in the mesangial area. Discover the latest research on IgA glomerulonephritis here.

Cryogenic Electron Microscopy

Cryogenic electron microscopy (Cryo-EM) allows the determination of biological macromolecules and their assemblies at a near-atomic resolution. Here is the latest research.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.