Trypsin-induced changes in energy distribution between photosystem I and photosystem II in pea thylakoid membranes

1995 ◽  
Vol 37 (1) ◽  
pp. 69-72 ◽  
Author(s):  
M.Y. Velitchkova ◽  
T.R. Lazarova ◽  
Y. Zanev
Keyword(s):  
Photosystem Ii ◽  
Energy Distribution ◽  
Photosystem I ◽  
Thylakoid Membranes ◽  
Induced Changes

Modulation of the Cytochrome b6/f Complex and Photosystem I Under Growth-Limiting Light in Amaranthus hypochondriacus, an NAD-ME C4 Plant

1996 ◽  
Vol 23 (3) ◽  
pp. 305 ◽  
Author(s):  
MV Sailaja ◽  
VSR Das
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Thylakoid Membranes ◽  
Bundle Sheath ◽  
C4 Plant ◽  
Cytochrome B6 ◽  
Amaranthus Hypochondriacus ◽  
Energy Consuming ◽  
Electron Transport Rates

Highly characteristic responses of thylakoid membranes were observed in function and composition when fully developed plants of Amaranthus hypochondriacus L. grown under light sufficient (2000 μmol m-2 s-1) conditions were transferred to light limited conditions (650 μmol m-2 s-1 and 200 μmol m-2 s-1). The whole-chain, photosystem I and photosystem II electron transport rates were depressed in both bundle sheath and mesophyll thylakoids with remarkable differences between them in variation of rates under limiting light. The reduction in PSI electron transport in the mesophyll could be attributed to reduced PSI centres, while in the bundle sheath, a modulation of cytochrome b6/f complex regulated the rates of PSI electron transport. The requirement for an unaltered number of PSI centres under limiting light in the bundle sheath is ascribed to operation of an energy-consuming C4 pump.

Freeze-fracture analysis of thylakoid membranes and photosystem I and II enriched fractions from Phormidium laminosum

1986 ◽  
Vol 80 (1) ◽  
pp. 57-73
Author(s):  
R.E. Glick ◽  
R.E. Triemer ◽  
B.A. Zilinskas
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Freeze Fracture ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Fracture Face ◽  
Phormidium Laminosum ◽  
Hydrophobic Component ◽  
Photosystem I And Ii ◽  
Protoplasmic Fracture Face

Thylakoid membranes of the thermophilic cyanobacterium Phormidium laminosum have been fractionated into photosystem II and photosystem I particles. These fractions have been characterized by their partial electron transport activities, and biochemical and spectral properties. Exoplasmic fracture face and protoplasmic fracture face particles in the unfractionated thylakoid membranes were shown to correspond in size to particles in freeze-fractured photosystem II and photosystem I fractions, respectively. Differences between the histograms of the thylakoid membrane protoplasmic fracture face particles and the isolated photosystem I particles suggest that in addition to photosystem I complexes some of the particles on the thylakoid protoplasmic fracture face may be related to cytochrome b/f complexes, the hydrophobic component of the coupling factor, or respiratory complexes.

scholarly journals Evidence for thylakoid membrane fusion during zygote formation in Chlamydomonas reinhardtii.

1991 ◽  
Vol 114 (5) ◽  
pp. 905-915 ◽  
Author(s):  
B Baldan ◽  
J Girard-Bascou ◽  
F A Wollman ◽  
J Olive
Keyword(s):  
Photosystem Ii ◽  
Chlamydomonas Reinhardtii ◽  
Photosystem I ◽  
Thylakoid Membrane ◽  
De Novo ◽  
Electron Flow ◽  
Thylakoid Membranes ◽  
Structural Basis ◽  
Zygote Formation ◽  
Thin Sections

To understand whether fusions of thylakoid membranes from the parental chloroplasts occurred during zygote formation in Chlamydomonas reinhardtii, we performed an ultrastructural analysis of the zygotes produced by crossing mutants lacking photosystem I or II protein complexes, in the absence of de novo chloroplast protein synthesis. Thylakoid membranes from each parent could be distinguished on thin sections due to their organization in "supergrana" in mutants lacking photosystem I centers, by freeze-fracturing due to the absence of most of the exoplasmic-face (EF) particles in mutants lacking photosystem II centers, by immunocytochemistry using antibodies directed against photosystem II subunits. We demonstrate that a fusion of the thylakoid membranes occurred during zygote formation approximately 15 h after mating. These fusions allowed a lateral redistribution of the thylakoid membrane proteins. These observations provide the structural basis for the restoration of photosynthetic electron flow in the mature zygote that we observed in fluorescence induction experiments.

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