scholarly journals Chromatic photoacclimation, photosynthetic electron transport and oxygen evolution in the Chlorophyll d-containing oxyphotobacterium Acaryochloris marina

2007 ◽  
Vol 1767 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Rosalyn S. Gloag ◽  
Raymond J. Ritchie ◽  
Min Chen ◽  
Anthony W.D. Larkum ◽  
Rosanne G. Quinnell
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Photosynthetic Electron Transport ◽  
Acaryochloris Marina ◽  
Chlorophyll D

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.

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.

Quantum Requirement of Photosynthesis in the Primarily Chlorophyll d Containing Prokaryote Acaryochloris marina

1997 ◽  
Vol 52 (9-10) ◽  
pp. 636-638 ◽  
Author(s):  
Shigetoh Miyachi ◽  
Kerstin Strassdat ◽  
Hideaki Miyashita ◽  
Horst Senger
Keyword(s):  
Energy Transfer ◽  
Reaction Center ◽  
Oxygen Evolution ◽  
Photosynthetic Oxygen Evolution ◽  
Efficient Energy Transfer ◽  
Efficient Energy ◽  
Quantum Requirement ◽  
Acaryochloris Marina ◽  
Photosynthetic Oxygen ◽  
Chlorophyll D

The recently isolated and characterized unicellular photosynthetic prokaryote Acaryochloris marina (Miyashita et al., 1996) contains chlorophylls a, d , and traces of a chlorophyll c-like pigment as well as phycocyanin. a type of allophycocyanin, zeaxanthin and cx-carotene, chlorophyll d being the predominant chlorophyll component. Quantum requirement measurements of the photosynthetic oxygen evolution resulted in about 12 quanta for excitation of chlorophylls a and d and 18 for phycocyanin. The data also revealed that these pigments are involved in energy absorption for photosynthetic oxygen evolution. Energy is transferred efficiently and equally well between the chlorophylls. Light absorbed by phycocyanin which is organized in phycobiliprotein aggregates (M arquardt et al., 1997), results in a less efficient energy transfer to the reaction center chlorophylls

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.

Characterization of the Inhibition of Photosynthetic Electron Transport in Pea Chloroplasts by the Herbicide 4,6-Dinitro-o-cresol by Comparative Studies with 3-(3,4-Dichlorophenyl)-1,1- dimethylurea

1978 ◽  
Vol 33 (5-6) ◽  
pp. 413-420 ◽  
Author(s):  
J. J. S. van Rensen ◽  
D. Wong ◽  
Govindjee
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Chlorophyll A ◽  
Oxygen Evolution ◽  
Chlorophyll A Fluorescence ◽  
Chlorophyll Concentration ◽  
Fluorescence Emission ◽  
Photosynthetic Electron Transport ◽  
Percent Inhibition ◽  
Mechanism Of Inhibition

An attempt to characterize the mechanism of inhibition of photosynthetic electron transport in isolated pea chloroplasts by the herbicide 4,6-dinitro-o-cresol (DNOC) by a comparison with the effects of 3-(3,4-dichlorophenyl)-1.1-dimethylurea (DCMU) revealed the following: 1.The percent inhibition of oxygen evolution by a given herbicide concentration is the same at various light intensities except at very low intensities where the percent inhibition becomes larger. The same results are obtained with the herbicide DCMU. 2.The concentration of DCMU causing 50% inhibition of oxygen evolution decreases with de­creasing chloroplast (and thus of chlorophyll) concentration. With DNOC, the relative decrease is much less than with DCMU. At the inhibited molecule, there appears to be a cooperative binding of DCMU with two binding sites and a noncooperative binding of DNOC with only one binding site. 3.The chlorophyll a fluorescence induction is influenced by DNOC in the same characteristic way as it is by DCMU: both herbicides cause a faster rise in fluorescence yield than in control chloroplasts, although a higher concentration of the former is required for the same effect. 4.The chlorophyll fluorescence emission spectra at 77 CK show a slight decrease in the bands at 685 and 735 nm, and no or only a very slight decrease at 695 nm upon addition of high con­centrations of either DCMU or DNOC before the onset of illumination. 5.The degree of polarization of chlorophyll a fluorescence is lower after addition of DCMU or DNOC upon excitation by 460 or 660 nm light. It is concluded that, although the chemical structure of DNOC is completely different from that of DCMU, its site and mechanism of inhibition is similar to that of DCMU. Both herbicides inhibit electron transport between the primary electron acceptor of photosystem II and the plastoquinone pool. This causes a closing of the reaction centers of photosystem II. However, the interaction with the inhibited molecule is different for the two herbicides.

Two Sites of Inhibition of the Photosynthetic Electron Transport Chain by the Herbicide Trifluralin

1981 ◽  
Vol 36 (9-10) ◽  
pp. 853-855 ◽  
Author(s):  
Magdolna Droppa ◽  
Sándor Demeter ◽  
Gábor Horváth
Keyword(s):  
Electron Transport ◽  
Oxygen Evolution ◽  
Electron Transport Chain ◽  
Specific Inhibitor ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Low Concentrations ◽  
Transport Chain ◽  
Inhibitory Site

Abstract The effect of trifluralin on the photosynthetic electron transport has been investigated by oxygen evolution and thermoluminescence m easurem ents. The results confirm the earlier observations that trifluralin at low concentrations blocks electron transport between the two photosystems probably at the same site as DBMIB does. At higher concentrations however, trifluralin inhibits the reaction from H2O →pBQ also and affects the thermoluminescence of chloroplasts in a manner sim ilar to DCMU. These results suggest that trifluralin has a second inhibitory site therefore the use of trifluralin as a specific inhibitor of electron transport has to be questioned.

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