Binding of Copper(II) to Proteins of the Photosynthetic Membrane and its Correlation with Inhibition of Electron Transport in Class II Chloroplasts of Spinach

1977 ◽  
Vol 32 (7-8) ◽  
pp. 605-610 ◽  
Author(s):  
Gerhard Vierke ◽  
Peter Struckmeier
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Room Temperature ◽  
Photosynthetic Electron Transport ◽  
Signal Amplitude ◽  
Class Ii ◽  
Photosynthetic Membrane ◽  
Temperature Spectrum ◽  
Room Temperature Spectrum ◽  
Epr Signal

Abstract Incubation of class II chloroplasts of spinach with copper in the light at pH = 8 in concentrations that inhibit oxygen evolution results in the formation of a copper (II) protein complex with the photosynthetic membrane. The EPR spectra indicate that the four nearest ligands to Cu(II) consist of three oxygen atoms and one nitrogen atom. The copper (II) protein appears to be pre­ dominantly associated with photosystem II. The formation of this protein as measured by the EPR signal amplitude of its room temperature spectrum correlates with the inhibition of oxygen evolution and of electron transport within photosystem I. This result indicates that the inhibition of photosynthetic electron transport by copper may be due to the formation of a copper (II) chelate with a membrane protein.

scholarly journals Lateral PbS Photovoltaic Devices for High Performance Infrared and Terahertz Photodetectors

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1692
Author(s):  
Emmanuel K. Ampadu ◽  
Jungdong Kim ◽  
Eunsoon Oh
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Photovoltaic Device ◽  
Photovoltaic Devices ◽  
Temperature Spectrum ◽  
Terahertz Region ◽  
Room Temperature Spectrum ◽  
Ftir Spectrometer ◽  
Titanium Substrates ◽  
Deposition Conditions

We fabricated a lateral photovoltaic device for use as infrared to terahertz (THz) detectors by chemically depositing PbS films on titanium substrates. We discussed the material properties of PbS films grown on glass with varying deposition conditions. PbS was deposited on Ti substrates and by taking advantage of the Ti/PbS Schottky junction, we discussed the photocurrent transients as well as the room temperature spectrum response measured by Fourier transform infrared (FTIR) spectrometer. Our photovoltaic PbS device operates at room temperature for wavelength ranges up to 50 µm, which is in the terahertz region, making the device highly applicable in many fields.

scholarly journals TIP family aquaporins play role in chloroplast osmoregulation and photosynthesis

2020 ◽  
Author(s):  
Azeez Beebo ◽  
Ahmad Zia ◽  
Christopher R. Kinzel ◽  
Andrei Herdean ◽  
Karim Bouhidel ◽  
...  
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Electron Transport ◽  
Chloroplast Envelope ◽  
Photosynthetic Oxygen Evolution ◽  
Wild Type ◽  
Thylakoid Lumen ◽  
Photosynthetic Oxygen ◽  
Osmotic Treatment ◽  
Envelope Membranes

SUMMARYPhotosynthetic oxygen evolution by photosystem II requires water supply into the chloroplast to reach the thylakoid lumen. A rapid water flow is also required into the chloroplast for optimal oxygen evolution and to overcome osmotic stress. The mechanisms governing water transport in chloroplasts are largely unexplored. Previous proteomics indicated the presence of three aquaporins from the tonoplast intrinsic protein (TIP) family, TIP1;1, TIP1;2 and TIP2;1, in chloroplast membranes of Arabidopsis thaliana. Here we revisited their location and studied their role in chloroplasts. Localization experiments indicated that TIP2;1 resides in the thylakoid, whereas TIP1;2 is present in both thylakoid and envelope membranes. Mutants lacking TIP1;2 and/or TIP2;1 did not display a macroscopic phenotype when grown under standard conditions. The mutant chloroplasts and thylakoids underwent less volume changes than the corresponding wild type preparations upon osmotic treatment and in the light. Significantly reduced rates of photosynthetic electron transport were obtained in the mutant leaves, with implications on the CO2 fixation rates. However, electron transport rates did not significantly differ between mutants and wild type when isolated thylakoids were examined. Less acidification of the thylakoid lumen was measured in mutants thylakoids, resulting in a slower induction of delta pH-dependent photoprotective mechanisms. These results identify TIP1;2 and TIP2;1 as chloroplast proteins and highlight their importance for osmoregulation and optimal photosynthesis. A third aquaporin, TIP1;1, is present in the chloroplast envelope, and may play role in photosynthesis under excessive light conditions, as based on the weak photosynthetic phenotype of its mutant.

scholarly journals Assignment for the Infrared Spectrum of Solid Sodium Propionate from Low-Temperature Measurements in Combination with 13C Isotopic Shifts

1987 ◽  
Vol 42 (5) ◽  
pp. 477-484 ◽  
Author(s):  
Masato Kakihana ◽  
Tadashi Nagumo
Keyword(s):  
Low Temperature ◽  
Infrared Spectrum ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Sodium Propionate ◽  
Coupled Modes ◽  
Temperature Spectrum ◽  
Isotopic Shifts ◽  
Complete Assignment ◽  
Room Temperature Spectrum

The infrared spectra of CH3CH2COONa and its 13C-labeled modifications (1-13C, 2-13C, and 3-13C) suspended in KBr disks were measured in the region 4000 -200 cm-1 at room temperature and liquid nitrogen temperature. Overlapping complex band contours appeared in some regions of the room temperature spectrum, most notably in the region 1500 -1350 cm-1, where 5 fundamentals having contributions from the methyl deformation, methylene bending, and carboxylate stretching modes should occur. In contrast to this, excellent resolution was reached at the low temperature, from which all 22 fundamentals expected in the whole spectral region investigated were detected. A complete assignment of the fundamentals is proposed mainly on the basis of the characteristic isotopic shifts of the three 13C substituted sodium propionate species. A fair number of the fundamentals were found to feature coupled modes having contributions from several group vibrations.

Photosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 1: Photophysical Processes, Membrane Energization. George AkoyunoglouPhotosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 2: Photosynthetic Electron Transport and Photophosphorylation. George AkoyunoglouPhotosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 3: Structure and Molecular Organization of the Photosynthetic Membrane. George AkoyunoglouPhotosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 4: Regulation of Carboxylation-Oxigenation. George AkoyunoglouPhotosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 5: Chloroplast Development. George AkoyunoglouPhotosynthesis. Proceedings of the Fifth International Congress on Photosynthesis, September 7-13, 1980, Halkidiki, Greece. Volume 6: Photosynthesis and Productivity, Photosynthesis and Environment. George Akoyunoglou

1983 ◽  
Vol 58 (2) ◽  
pp. 262-262
Author(s):  
A. D. Krikorian
Keyword(s):  
Electron Transport ◽  
Chloroplast Development ◽  
Photosynthetic Electron Transport ◽  
Molecular Organization ◽  
International Congress ◽  
Photosynthetic Membrane ◽  
Photophysical Processes ◽  
Membrane Energization

Herbicides which Inhibit Electron Transport or Produce Chlorosis and Their Effect on Chloroplast Development in Radish Seedlings I. Chlorophyll a Fluorescence Transients and Photosystem II Activity

1982 ◽  
Vol 37 (3-4) ◽  
pp. 268-275 ◽  
Author(s):  
K. H. Grumbach
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll A ◽  
Oxygen Evolution ◽  
Chlorophyll A Fluorescence ◽  
Photosynthetic Electron Transport ◽  
Photosystem Ii Activity ◽  
Chlorophyll A Fluorescence Transients ◽  
Radish Seedlings ◽  
Fluorescence Transients

Abstract Diuron and bentazon are very strong inhibitors of the photosynthetic electron transport in isolated radish chloroplasts. The chlorosis producing herbicide SAN 6706 also inhibited the photosystem II dependent oxygen evolution. Aminotriazole had no effect. The inhibitor concentration for 50% inhibition of photosystem II activity was 10-7 m for diuron and 10-4 m for bentazon and SAN 6706 respectively.Diuron and bentazon quenched the chlorophyll a fluorescence transients in isolated radish chloroplasts drastically, while aminotriazole was not effective. It was of particular interest that the bleaching herbicide SAN 6706 inhibited photosystem II dependent oxygen evolution in a similar concentration as bentazon but had no effect on the chlorophyll a-fluorescence transients suggesting that SAN 6706 is not binding to the same site of the electron transport chain as diuron and bentazon.Apart from their direct influence on electron transport in isolated photosynthetically active chloroplasts the photosystem II and bleaching herbicides assayed also strongly affected photosynthesis in radish seedlings that were grown in the presence of the herbicides for a long time. As already obtained using isolated chloroplasts, photosystem II dependent oxygen evolution like the chlorophyll a fluorescence transients were strongly inhibited by the photosystem II herbicides diuron and bentazon. A reduction but no inhibition of photosystem II activity was observed in plants that were grown in the presence of aminotriazole. The pyridazinone SAN 6706 was behaving contradictory. In partly green plants photosystem II activity was still maintained and even higher than in untreated plants while in albinistic plants no photosynthetic activity was detected.

Influence of Bleaching Herbicides on Chlorophyll and Carotenoids

1979 ◽  
Vol 34 (11) ◽  
pp. 1047-1051 ◽  
Author(s):  
Karl-Josef Kunert ◽  
Peter Böger
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Green Alga ◽  
Photosynthetic Electron Transport ◽  
Pigment Content ◽  
Photosynthetic Oxygen Evolution ◽  
Direct Inhibition ◽  
Scenedesmus Acutus ◽  
Photosynthetic Oxygen ◽  
Chlorophyll Formation

Abstract Over 24 and 48 hour cultivation periods the influence of SAN 9789 (norflurazon), EMD-IT 5914 (difunon) and fluridone on growth, photosynthetic oxygen evolution and pigment content of the green alga Scenedesmus acutus was determined. Four effects were observed: a) Both carotenoid and chlorophyll formation were inhibited. b) Carotenoids were destroyed in the presence of air, but not nitrogen. The level of chlorophyll, however, did not change. c) β- (and α-) carotene was markedly decreased in the presence of oxygen. d) Photosynthetic oxygen evolution was decreased with the disappearance of carotenoids. These effects, which are accompanied by reduced growth, are believed to represent primary herbicidal modes of action. The decrease of oxygen evolution is not due to a direct inhibition of photosynthetic electron transport by the herbicides applied.

Action of EMD-IT 5914 on Chloroplasts

Weed Science ◽  
1978 ◽  
Vol 26 (3) ◽  
pp. 292-296 ◽  
Author(s):  
K. J. Kunert ◽  
P. Böger
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Direct Effect ◽  
Aminolevulinic Acid ◽  
Photosynthetic Electron Transport ◽  
Carotenoid Biosynthesis ◽  
Secondary Process ◽  
Chloroplast Pigments ◽  
Unicellular Algae ◽  
Chlorophyll Bleaching

The experimental herbicide EMD-IT 5914 [difunon, 5-dimethyl-amino-methylene-2-oxo-4-phenyl-2,5-dihydrofurane-carbonitrile-(3)] was applied to unicellular algae and its effect on growth, oxygen evolution and photosynthetic electron transport measured. Inhibition of biosynthesis of chloroplast pigments was evaluated in relation to the activities of porphobilinogenase and δ-aminolevulinic acid dehydratase. The only direct effect of the herbicide was an inhibition of carotenoid biosynthesis but not of photosynthetic electron transport or enzymic activities connected with porphyrin biosynthesis. Chlorophyll bleaching is considered to be a secondary process.

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