Function of Chlorophylls and Carotenoids in Thylakoid Membranes. Pigment Bleaching in Relation to PS-I and PS-II Activity of Subchloroplast Particles Prepared with Digitonin

Abstract An improved method for isolation of (photosystem II)-particles from Euglena gracilis, strain Z was established. PS II-particles isolated by ultrasonic treatment and following differential centrifugation show fluorescence emission and absorption spectra identical with in vivo properties of Euglena gracilis. These PS II-particles have only PS II-activity and contain CP a, the typical chlorophyll-protein-complex of PS II. No contamination of PS I-components are detectable.

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External electric-field effects on photosynthetic vesicles. The relationship of the rapid and slow phases of electrophotoluminescence in hypotonically swollen chloroplasts to PS I and PS II activity

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/0005-2728(85)90109-4 ◽

1985 ◽

Vol 806 (2) ◽

pp. 305-310 ◽

Cited By ~ 8

Author(s):

Marc Symons ◽

Rafi Korenstein ◽

Shmuel Malkin

Keyword(s):

Electric Field ◽

External Electric Field ◽

Electric Field Effects ◽

Ps Ii ◽

Field Effects ◽

Ps I ◽

Relationship Of ◽

The Relationship ◽

Ps Ii Activity

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The Stoichiometries of Supramolecular Complexes in Thylakoid Membranes From Spinach Chloroplasts

Functional Plant Biology ◽

10.1071/pp9870021 ◽

1987 ◽

Vol 14 (1) ◽

pp. 21 ◽

Cited By ~ 24

Author(s):

WS Chow ◽

AB Hope

Keyword(s):

Photosystem Ii ◽

Atpase Activity ◽

Thylakoid Membranes ◽

Coupling Factor ◽

Supramolecular Complexes ◽

Cyt B ◽

Ps Ii ◽

Ps I ◽

The Mean ◽

Isolated Chloroplasts

The concentrations of photosystem II (PS II), photosystem I (PS I) and cytochrome b/f complexes on a chlorophyll basis have been determined for chloroplasts of spinach grown under three irradiances in a glasshouse. Assaying PS II by atrazine binding gave concentrations that exceeded the estimates from flash-induced O2 or H+ yield by a factor of 1.21 � 0.04 (23). Since part of this factor (1.14) is expected to arise from missed turnovers in excited reaction centres, it is concluded that both methods are valid to determine [PS II] in gently isolated chloroplasts. The agreement between the methods also suggests that atrazine does not bind to additional sites of quenchers such as 'Q400', contrary to the suggestion of R. J. Dennenberg and P. A. Jursinic [Biochim. Biophys. Acta 808 (1985), 192-200]. Whilst [PS I] was independent of growth irradiances, [PS II] and [cyt f ] increased with irradiance, as did the latent ATPase activity, a measure of the concentration of coupling factor 1. If [PS I] is taken as constant at 1.65 mmol (mol Chl)-1, the mean stoichiometries of PS II : cyt b/f complex : PS I obtained at the minimum and maximum irradiances were 1.2 : 0.7 : 1 and 1.6 : 1.0 : 1 respectively, PS II being determined by atrazine binding.

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Thylakoid grana stacking revealed by multiplex genome editing of LHCII encoding genes

10.1101/2021.12.31.474624 ◽

2022 ◽

Author(s):

Zeno Guardini ◽

Rodrigo Lionel Gomez ◽

Roberto Caferri ◽

Johannes Stuttmann ◽

Luca Dall'Osto ◽

...

Keyword(s):

Energy Balance ◽

Light Exposure ◽

Thylakoid Membranes ◽

Land Plant ◽

Ps Ii ◽

Antenna Complex ◽

Ps I ◽

Repair Efficiency ◽

Rapid Changes ◽

Encoding Genes

Land plant chloroplasts differ from algal ones for their thylakoid membranes being organized in grana: piles of vesicles paired by their stromal surface, forming domains including Photosystem (PS) II and its antenna while excluding PS I and ATPase to stroma membranes, connecting grana stacks. The molecular basis of grana stacking remain unclear. We obtained genotypes lacking the trimeric antenna complex (Lhcb1-2-3), the monomeric Lhcb4-5-6, or both. Full deletion caused loss of grana, while either monomers or trimers support 50% stacking. The expression of Lhcb5 alone restored stacking at 50%, while Lhcb2 alone produced huge grana which broke down upon light exposure. Cyclic electron transport was maintained in the lack of stacking, while excitation energy balance between photosystems and the repair efficiency of damaged Photosystem II were affected. We conclude that grana evolved for need of regulating energy balance between photosystems under terrestrial canopy involving rapid changes in photon spectral distribution.

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Biochemical Characterization on Photosynthetic Activities during Dark Incubated Senescence of Wheat Primary Leaves by Gibberellic Acid

Asian Journal of Biochemistry, Genetics and Molecular Biology ◽

10.9734/ajbgmb/2019/v2i430067 ◽

2019 ◽

pp. 1-5

Author(s):

G. Fareeda ◽

S. D. S. Murthy

Keyword(s):

Water Oxidation ◽

Biochemical Characterization ◽

Crop Yields ◽

Moderate Increase ◽

Ps Ii ◽

Annual Crops ◽

Ps I ◽

Treated Leaf ◽

Photosynthetic Activities ◽

Ps Ii Activity

In annual crop plants like maize, rice and wheat etc. Senescence limits crop yields of annual crops like maize rice and wheat. Delayed leaf senescence is a desirable agronomic trait to improve crop yield. In this study 10 µM GA reduced the loss of wheat primary leaves under incubated dark conditions. GA reduced the loss of pigments, proteins, electron transport activities, spectral properties. The restoration of WCE activity by GA was closely associated with the restoration of PS II activity compared to that of PS I. GA treated leaf thylakoid membranes showed an increase in absorption at 680 nm moderate increase at 480 nm and 440 nm at 72 h during dark incubation. GA protected the degradation of water oxidation complex polypeptides (33, 23, 17 KDa) of PS II and slightly protected the PS I polypeptides.

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Atrazine Phytotoxicity to Common Bean and Redroot Pigweed under Different Temperatures

Weed Science ◽

10.1017/s0043174500051754 ◽

1992 ◽

Vol 40 (3) ◽

pp. 364-370 ◽

Cited By ~ 4

Author(s):

Kassim Al-Khatib ◽

Rick Boydston ◽

Robert Parker ◽

E. Patrick Fuerst

Keyword(s):

High Temperature ◽

Photosystem Ii ◽

Common Bean ◽

Thylakoid Membranes ◽

Ps Ii ◽

Foliar Absorption ◽

Redroot Pigweed ◽

Temperature Regimes ◽

Different Temperatures ◽

Ps Ii Activity

The basis for increased phytotoxicity of foliar-applied atrazine at high temperature in common bean and redroot pigweed was investigated. Plants were grown under low (15/10 C), medium (25/20 C), or high (35/30 C) temperature regimes. Atrazine absorption by plants grown under different temperatures increased with increasing temperatures in both species. Greater than 90% of absorbed atrazine remained in treated leaves and translocation was not altered by temperature in both species. Metabolism of atrazine by both hydroxylation and glutathione-conjugation was greater in plants grown at 35/30 than 15/10 C in both species. Foliar-applied atrazine reduced extractable photosystem II (PS II) activity as temperature increased in both species. Studies were also conducted on thylakoid membranes from plants not treated with atrazine. The I50for atrazine inhibition of PS II decreased and affinity of atrazine binding to thylakoid membranes increased as temperature increased in both species. We concluded that the increased phytotoxicity of atrazine at high temperatures is caused by enhanced foliar absorption and greater affinity of atrazine for the binding site.

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Photosystem II Inhibition by Pyran-enamine Derivatives

Zeitschrift für Naturforschung C ◽

10.1515/znc-1993-3-409 ◽

1993 ◽

Vol 48 (3-4) ◽

pp. 163-167

Author(s):

Koichi Yoneyama ◽

Yoshihiro Nakajima ◽

Masaru Ogasawara ◽

Hitoshi Kuramochi ◽

Makoto Konnai ◽

...

Keyword(s):

Electron Transport ◽

Photosystem Ii ◽

Thylakoid Membranes ◽

Major Determinant ◽

Ps Ii ◽

Structure Activity Relationships ◽

Structure Activity

Abstract Through the studies on structure-activity relationships of 5-acyl-3-(1-aminoalkylidene)-4-hydroxy-2 H-pyran-2,6(3 H)-dione derivatives in photosystem II (PS II) inhibition, overall lipophilicity of the molecule was found to be a major determinant for the activity. In the substituted N -benzyl derivatives, not only the lipophilicity but also the electronic and steric characters of the substituents greatly affected the activity. Their mode of PS II inhibition seemed to be similar to that of DCMU , whereas pyran-enamine derivatives needed to be highly lipophilic to block the electron transport in thylakoid membranes, which in turn diminished the permeability through biomembranes.

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Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach

Zeitschrift für Naturforschung C ◽

10.1515/znc-1992-1-212 ◽

1992 ◽

Vol 47 (1-2) ◽

pp. 63-68 ◽

Cited By ~ 3

Author(s):

Rekha Chaturvedi ◽

M. Singh ◽

P. V. Sane

Keyword(s):

Electron Transport ◽

Photosynthetic Electron Transport ◽

Oxygen Evolving Complex ◽

Reaction Centre ◽

Ps Ii ◽

Ps I ◽

S2 State ◽

The Stability ◽

Oxygen Evolving ◽

Spinach Thylakoids

Abstract The effect of exposure to strong white light on photosynthetic electron transport reactions of PS I and PS II were investigated in spinach thylakoids in the absence or presence of oxygen. Irrespective of the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence of oxygen is required for prevention of photoinactivation of thylakoids. The susceptibility of water-splitting complex in photoinactivation is indicated by our data from experiments with chloride-deficient chloroplast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre of PS II. DCMU-protected PS II and oxygen-evolving complex from photoinactivation. DCMU protection can also be interpreted in terms of the stability of the PS II complex when it is in S2 state.

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