Preparation protocols for high-activity Photosystem II membrane particles of green algae and higher plants, pH dependence of oxygen evolution and comparison of the S2-state multiline signal by X-band EPR spectroscopy

2000 ◽  
Vol 55 (2-3) ◽  
pp. 138-144 ◽  
Author(s):  
Hilmar Schiller ◽  
Holger Dau
Keyword(s):  
Photosystem Ii ◽  
High Activity ◽  
Oxygen Evolution ◽  
Green Algae ◽  
Epr Spectroscopy ◽  
Higher Plants ◽  
Ph Dependence ◽  
Membrane Particles ◽  
X Band ◽  
S2 State

scholarly journals Q-Band EPR of the S2 State of Photosystem II Confirms an S=5/2 Origin of the X-Band g=4.1 Signal

2004 ◽  
Vol 87 (4) ◽  
pp. 2885-2896 ◽  
Author(s):  
Alice Haddy ◽  
K.V. Lakshmi ◽  
Gary W. Brudvig ◽  
Harry A. Frank
Keyword(s):  
Photosystem Ii ◽  
X Band ◽  
S2 State

Inhibition of Photosystem II-Reactions in Blue-Green Algae by the Antisera to Lutein and Neoxanthin

1977 ◽  
Vol 32 (1-2) ◽  
pp. 118-124 ◽  
Author(s):  
Georg H. Schmid ◽  
Helga List ◽  
Alfons Radunz
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Green Algae ◽  
Higher Plants ◽  
Algal Species ◽  
Nostoc Muscorum ◽  
Blue Green Algae ◽  
Oscillatoria Chalybea ◽  
Electron Donation ◽  
Tetramethyl Benzidine

An antiserum to lutein agglutinates thylakoids of Nostoc muscorum and Oscillatoria chalybea. From this it follows that lutein is located in the outer surface of the thylakoid membrane of these blue-green algae. The same result is obtained for an antiserum to neoxanthin. As neoxanthin is supposed not to occur in blue-green algae it follows that in this case the antibody action should be directed towards a carotenoid with allenic structure. The antisera to lutein and neoxanthin inhibit in both investigated algal species photosynthetic electron transport on the oxygen-evolving side of photosystem II. Moreover, the inhibition sites of both antisera are identical in Nostoc muscorum and are located between the sites of electron donation of the artificial electron donors tetramethyl benzidene and diphenylcarbazide. In the case of the blue-green alga Oscillatoria chalybea the inhibition sites of both antisera differ. Whereas the inhibition site of the antiserum to neoxanthin lies again between the sites of electron donation of tetramethyl benzidine and di­phenylcarbazide, the inhibition site of the antiserum to lutein appears to be situated at least partially beyond the site of electron donation of tetramethyl benzidine. The degree of inhibition of electron transport reactions with Nostoc muscorum is for both antisera 50 - 60 per cent and is pH-dependent. The pH-optimum lies at pH 7.2 for the antiserum to neoxanthin and at 7.8 for the antiserum to lutein. In comparison to this data the same antisera inhibit electron transport in chloroplasts from higher plants only by 20%. This low degree of inhibition in higher plants is apparently due to the fact that the surfaces of the thylakoids are not accessible to antibodies within the grana. In contrast to this the thylakoid surfaces of blue-green algae are fully accessible because the thylakoids are unstacked. The thylakoids of Oscillatoria chalybea have the tendency towards aggregation. Therefore, the results concerning the accessibility of the carotenoids to antibodies are not so clear cut as with Nostoc muscorum.

Stability of the S3 and S2 State Intermediates in Photosystem II Directly Probed by EPR Spectroscopy

Biochemistry ◽  
2011 ◽  
Vol 51 (1) ◽  
pp. 138-148 ◽  
Author(s):  
Guiying Chen ◽  
Guangye Han ◽  
Erik Göransson ◽  
Fikret Mamedov ◽  
Stenbjörn Styring
Keyword(s):  
Photosystem Ii ◽  
Epr Spectroscopy ◽  
S2 State

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

scholarly journals Effects of Annealing Temperature on the Oxygen Evolution Reaction Activity of Copper–Cobalt Oxide Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 657
Author(s):  
Geul Han Kim ◽  
Yoo Sei Park ◽  
Juchan Yang ◽  
Myeong Je Jang ◽  
Jaehoon Jeong ◽  
...  
Keyword(s):  
High Activity ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Cobalt Hydroxide ◽  
Ni Foam ◽  
Electron Conduction

Developing high performance, highly stable, and low-cost electrodes for the oxygen evolution reaction (OER) is challenging in water electrolysis technology. However, Ir- and Ru-based OER catalysts with high OER efficiency are difficult to commercialize as precious metal-based catalysts. Therefore, the study of OER catalysts, which are replaced by non-precious metals and have high activity and stability, are necessary. In this study, a copper–cobalt oxide nanosheet (CCO) electrode was synthesized by the electrodeposition of copper–cobalt hydroxide (CCOH) on Ni foam followed by annealing. The CCOH was annealed at various temperatures, and the structure changed to that of CCO at temperatures above 250 °C. In addition, it was observed that the nanosheets agglomerated when annealed at 300 °C. The CCO electrode annealed at 250 °C had a high surface area and efficient electron conduction pathways as a result of the direct growth on the Ni foam. Thus, the prepared CCO electrode exhibited enhanced OER activity (1.6 V at 261 mA/cm2) compared to those of CCOH (1.6 V at 144 mA/cm2), Co3O4 (1.6 V at 39 mA/cm2), and commercial IrO2 (1.6 V at 14 mA/cm2) electrodes. The optimized catalyst also showed high activity and stability under high pH conditions, demonstrating its potential as a low cost, highly efficient OER electrode material.

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