Low-temperature fluorescence emission spectra and chlorophyll-protein complexes in mutants of Chlamydomonas reinhardtii: Evidence for a new chlorophyll-a-protein complex related to Photosystem I

1986 ◽  
Vol 851 (3) ◽  
pp. 395-406 ◽  
Author(s):  
Jacques Garnier ◽  
Jeannine Maroc ◽  
Denise Guyon
Keyword(s):  
Low Temperature ◽  
Chlorophyll A ◽  
Photosystem I ◽  
Protein Complex ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein

scholarly journals Chloroplast-cytoplasmic interrelations involved in chloroplast development in Chlamydomonas reinhardi y-1: effect of selective depletion of chloroplast translates.

1980 ◽  
Vol 87 (1) ◽  
pp. 124-131 ◽  
Author(s):  
J M Gershoni ◽  
I Ohad
Keyword(s):  
Chloroplast Development ◽  
De Novo ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Bisphosphate Carboxylase ◽  
Whole Cells ◽  
Chlorophyll Protein Complexes ◽  
Reported Data

Chlamydomonas reinhardi y-1 cells grown in the dark in the presence of chloramphenicol (CD cells) are depleted of photosynthetic membranes and 70S translates. These cells were found to be unable to synthesize chlorophyll in the light until chloroplast protein synthesis was resumed. On the other hand, CD cells acquired the capacity to partially green in the presence of cycloheximide. This greening was characterized by the development of photosynthetic activity, as demonstrated by light-dependent oxygen evolution of whole cells and by measurements of ribulose-1,5-bisphosphate carboxylase and fluorescence kinetics. The chlorophyll synthesized de novo during greening in the absence of 80S ribosomal activity was organized in chlorophyll-protein complexes, as ascertained by low-temperature fluorescence-emission spectra. The morphology of these cells appeared to be normal. A model has been proposed as a working hypothesis, which could account for the phenomena described above and previously reported data pertaining to chloroplast development.

Changes of the Photosynthetic Apparatus in Spirulina Cyanobacterium by Sodium Stress

2000 ◽  
Vol 55 (1-2) ◽  
pp. 16-22 ◽  
Author(s):  
Kavita Verma ◽  
Prasanna Mohanty
Keyword(s):  
Chlorophyll A ◽  
Photosystem I ◽  
Protein Interactions ◽  
Room Temperature ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Energy Harvest ◽  
Fluorescence Emission Spectra ◽  
Transfer Processes

Abstract Spirulina platensis trichomes grown in Zarrouks medium having total Na+ concentration as 0.14 ᴍ when transfered to fresh Zarrouks medium containing enhanced level of Na+ ions equal to 0.86 ᴍ showed 30% more accumulation of Na+ intracellularly as compared to the control. An inhibition of photosystem II activity to almost 66% was observed. Also due to this exposure to high Na+, the room temperature absorption characteristics of Spirulina trichomes and the thylakoid membrane preparations w ere altered indicating changes in the chromophore protein interactions and alterations in the phycocyanin/allophycocyanin ratio; there by affecting the energy harvest and energy transfer processes. An increase in the carotenoid absorption was two fold over the control in the treated sample. Similarly, room temperature and low temperature (77 K) fluorescence emission spectra collectively suggested alterations in the chlorophyll a emissions, F 726 of photosystem I reflecting changes in the lipid protein environment of the thylakoid. Our results indicate that in Spirulina the enhanced Na+ level alters the energy harvest and transfer processes. It also affected the emission characteristics of chlorophyll a of photosystem I.

scholarly journals Thermal Stress, Aggregation of Chlorophyll-Protein Complexes, and Light-Dependent Recovery of PSII activity in Wheat Seedlings

2021 ◽  
Vol 68 (5) ◽  
pp. 867-872
Author(s):  
M. S. Khristin ◽  
T. N. Smolova ◽  
V. D. Kreslavski
Keyword(s):  
Low Temperature ◽  
Structural Changes ◽  
Protein Complexes ◽  
Red Light ◽  
Photochemical Activity ◽  
Wheat Seedlings ◽  
Psii Activity ◽  
Temperature Spectra ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein

Abstract The dynamics of changes in the photochemical activity of photosystem II (PSII) and low-temperature spectra at 77 K in the first leaves of 11-day winter wheat plants Triticum aestivum L., as well as structural changes in chlorophyll-protein complexes (CPC) of thylakoid membranes during recovery after a short-term (20 min) heating at a temperature of 42°C, were studied. Changes in the Fv/Fm, F735/F695, and F735/F685 ratios indicate inhibition of PSII immediately after heating. Using nondenaturing electrophoresis, it was shown that the light-harvesting Chl a/b complex of PSII does not aggregate immediately after heating but after several hours, after 6 h the desagregation of CPC was observed, which was consistent with an increase in the Fv/Fm ratio upon recovery. The influence of temperature, intensity, and quality of light (white, blue, and red light) on the recovery of PSII activity and low-temperature fluorescence spectra was studied. It was concluded that the recovery is a photo-activated low-energy process, independent of photosynthesis, and the most effective in blue light.

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