scholarly journals Comparative analysis of biochemical properties of mesophyll and bundle sheath chloroplasts from various subtypes of C4 plants grown at moderate irradiance.

2006 ◽  
Vol 53 (4) ◽  
pp. 709-719 ◽  
Author(s):  
Elzbieta Romanowska ◽  
Anna Drozak
Keyword(s):  
Protein Complexes ◽  
Fluorescence Emission ◽  
Biochemical Properties ◽  
Photochemical Activity ◽  
Bundle Sheath ◽  
C4 Plants ◽  
Emission Characteristic ◽  
Panicum Maximum ◽  
Light Conditions ◽  
Mechanical Methods

The photochemical characteristics of mesophyll and bundle sheath chloroplasts isolated from the leaves of C4 species were investigated in Zea mays (NADP-ME type), Panicum miliaceum (NAD-ME type) and Panicum maximum (PEP-CK type) plants. The aim of this work was to gain information about selected photochemical properties of mesophyll and bundle sheath chloroplasts isolated from C4 plants grown in the same moderate light conditions. Enzymatic as well as mechanical methods were applied for the isolation of bundle sheath chloroplasts. In the case of Z. mays and P. maximum the enzymatic isolation resulted in the loss of some thylakoid polypeptides. It was found that the PSI and PSII activities of mesophyll and bundle sheath chloroplasts of all species studied differed significantly and the differences correlated with the composition of pigment-protein complexes, photophosphorylation efficiency and fluorescence emission characteristic of these chloroplasts. This is the first report showing differences in the photochemical activities between mesophyll chloroplasts of C4 subtypes. Our results also demonstrate that mesophyll and bundle sheath chloroplasts of C4 plants grown in identical light conditions differ significantly with respect to the activity of main thylakoid complexes, suggesting a role of factor(s) other than light in the development of photochemical activity in C4 subtypes.

Biochemical properties and ultrastructure of mesophyll and bundle sheath thylakoids from maize (Zea mays) chloroplasts

2020 ◽  
Vol 47 (11) ◽  
pp. 970
Author(s):  
Nahida K. Aliyeva ◽  
Durna R. Aliyeva ◽  
Saftar Y. Suleymanov ◽  
Fuad H. Rzayev ◽  
Eldar K. Gasimov ◽  
...  
Keyword(s):  
Zea Mays ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Cell Types ◽  
Biochemical Properties ◽  
Photochemical Activity ◽  
Bundle Sheath ◽  
M Cells ◽  
Fluorescence Emission Spectra ◽  
Light Harvesting Complex

A characteristic feature of C4 plants is the differentiation of the photosynthetic leaf tissues into two distinct cell types: mesophyll (M) and bundle sheath (BS) cells. We have investigated several biochemical parameters, including pigment composition, polypeptide patterns, fluorescence at 77K, the activity of photosystems and ultrastructure of mesophyll and bundle sheath chloroplasts of maize (Zea mays L.) plants. It is shown that the BS chloroplasts have ~2-fold higher chlorophyll a/b ratio than M chloroplasts, 6.15 and 3.12 respectively. The PSI apoprotein (68 kDa) was more abundant in BS than in M thylakoids. Polypeptides belonging to PSII core antenna, are in similar amounts in both types of membranes, but the 45kDa band is more intensive in M thylakoids. Polypeptides in the region of 28–24 kDa of the light-harvesting complex of PSII (LHCII) are also present in both types of chloroplasts, though their amounts are reduced in BS thylakoids. The chlorophyll fluorescence emission spectra in M cells showed the presence of three bands at 686, 695 and 735 nm characteristics of LHCII, PSII core and PSI complexes, respectively. However, in the fluorescence spectrum of agranal plastids, there are almost traces of the band at 695 nm, which belongs to the PSII core complex. The research results revealed that the photochemical activity of PSII in BS chloroplasts is ~5 times less than in the chloroplasts of M cells. The highest PSI activity was found in maize BS chloroplasts.

Phosphoenolpyruvate Carboxykinase in C4 Plants: Its Role and Regulation

1997 ◽  
Vol 24 (4) ◽  
pp. 459 ◽  
Author(s):  
Robert P. Walker ◽  
Richard M. Acheson ◽  
László I. Técsi ◽  
Richard C. Leegood
Keyword(s):  
Molecular Mass ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
C4 Plants ◽  
Panicum Maximum ◽  
C4 Plant ◽  
Cam Plants ◽  
Crude Extracts ◽  
High Concentrations ◽  
Regulatory Properties

Some of the recent findings which revise our view of the role and regulation of phosphoenolpyruvate carboxykinase (PEPCK) in C4 plants are discussed. Evidence is presented that PEPCK is present at appreciable activities in the bundle-sheath of some NADP-malic enzyme-type C4 plants, such as maize, but it was not detectable in NAD-malic enzyme-type C4 plants. PEPCK is rapidly inactivated in crude extracts of leaves of the C4 plant, Panicum maximum. This inactivation could be prevented by high concentrations of dithiothreitol or by the inclusion of ADP or ATP, suggesting the involvement of thiols at the active site. PEPCK is also subject to rapid proteolysis in crude extracts of a range of C4 plants, resulting in cleavage to a smaller (62 kDa) form. This can be reduced by extraction at high pH and by the inclusion of SDS, but it means that intact PEPCK has never been purified from a C4 plant. The molecular mass of PEPCK varies considerably in C4 plants, unlike C3 and CAM plants in which it is usually 74 kDa. PEPCK is phosphorylated during darkness (and reversed by light) in some C4 plants with PEPCK of a larger molecular mass, such as Panicum maximum (71 kDa), but it was not phosphorylated in the PEPCK-type C4 plant, Sporobolus pyramidalis (69 kDa). The known regulatory properties of PEPCK are discussed in relation to its role in C4 photosynthesis, in particular its sensitivity to regulation by adenylates and by Mn2+.

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.

scholarly journals High light induces species specific changes in the membrane lipid composition of Chlorella

2020 ◽  
Vol 477 (13) ◽  
pp. 2543-2559
Author(s):  
Janka Widzgowski ◽  
Alexander Vogel ◽  
Lena Altrogge ◽  
Julia Pfaff ◽  
Heiko Schoof ◽  
...  
Keyword(s):  
Cell Membranes ◽  
De Novo ◽  
Algal Cell ◽  
Isotopic Labeling ◽  
Biochemical Properties ◽  
Membrane Lipid ◽  
Light Conditions ◽  
Hydrophobic Barrier ◽  
Glycerolipid Composition ◽  
Species Specific

Algae have evolved several mechanisms to adjust to changing environmental conditions. To separate from their surroundings, algal cell membranes form a hydrophobic barrier that is critical for life. Thus, it is important to maintain or adjust the physical and biochemical properties of cell membranes which are exposed to environmental factors. Especially glycerolipids of thylakoid membranes, the site of photosynthesis and photoprotection within chloroplasts, are affected by different light conditions. Since little is known about membrane lipid remodeling upon different light treatments, we examined light induced alterations in the glycerolipid composition of the two Chlorella species, C. vulgaris and C. sorokiniana, which differ strongly in their ability to cope with different light intensities. Lipidomic analysis and isotopic labeling experiments revealed differences in the composition of their galactolipid species, although both species likely utilize galactolipid precursors originated from the endoplasmic reticulum. However, in silico research of de novo sequenced genomes and ortholog mapping of proteins putatively involved in lipid metabolism showed largely conserved lipid biosynthesis pathways suggesting species specific lipid remodeling mechanisms, which possibly have an impact on the response to different light conditions.

Physiological Significance of Overproduced Carotenoids in Transformants of the Cyanobacterium Synechococcus PCC7942

1999 ◽  
Vol 54 (3-4) ◽  
pp. 191-198
Author(s):  
Navassard V. Karapetyan ◽  
Ute Windhövel ◽  
Alfred R. Holzwarth ◽  
Peter Böger
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Fluorescence Induction ◽  
Carotenoid Content ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Whole Cells ◽  
Fluorescence Excitation Spectra ◽  
Synechococcus Pcc7942

Abstract The functional location of carotenoids in the photosynthetic apparatus of -crtB and -pys transformants of the cyanobacterium Synechococcus PCC7942 was studied and compared with a control strain -pFP 1-3. These transformants overproduce carotenoids due to the insertion of an additional foreign phytoene synthase gene. A higher carotenoid content was found for -crtB and -pys transformants both in whole cells and isolated membranes; the -crtB transformant was also enriched with chlorophyll. 77-K fluorescence emission and excitation spectra of the phycobilin-free membranes were examined for a possible location of overproduced carotenoids in pigment-protein complexes in situ. A similar ratio of the amplitudes of fluorescence bands at 716 and 695 nm emitted by photosystems I and II, found for the three strains, indicates that the stoichiometry between photosystems of the transformants was not changed. Overproduced carotenoids are not located in the core antenna of photosys­ tem I, since 77-K fluorescence excitation spectra for photosystem I of isolated membranes from the studied strains do not differ in the region of carotenoid absorption. When illuminated with light of the same intensity but different quality, absorbed preferentially by either carotenoids, chlorophylls or phycobilins, respectively, oxygen evolution was found always higher in the transformants -crtB and -pys than in -pFP 1-3 control cells. Identical kinetics of fluorescence induction of all strains under carotenoid excitation did not reveal a higher activity of photosystem II in cells enriched with carotenoids. It is suggested that overproduced carotenoids of the transformants are not involved in photosynthetic light-harvesting; rather they may serve to protect the cells and its membranes against photodestruction.

scholarly journals Stability of Chlorophyll a Monomer Incorporated into Cremophor EL Nano-Micelles under Dark and Moderate Light Conditions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5059
Author(s):  
Ewa Janik-Zabrotowicz ◽  
Marta Arczewska ◽  
Patrycja Prochniewicz ◽  
Izabela Świetlicka ◽  
Konrad Terpiłowski
Keyword(s):  
Chlorophyll A ◽  
Self Assembly ◽  
Molecular Spectroscopy ◽  
Fluorescence Emission ◽  
Molecular Organization ◽  
Cremophor El ◽  
Light Conditions ◽  
Fluorescence Emission Spectra ◽  
Pigment Stability ◽  
The Stability

In this paper, stability of chlorophyll a monomers encapsulated into the Cremophor EL nano-micelles was studied under dark and moderate light conditions, typical of a room with natural or artificial lighting, in the presence of oxygen. The pigment stability against visible light was determined using the dynamic light scattering and molecular spectroscopy (UV-Vis absorption and stationary fluorescence) methods. Chlorophyll a, at the molar concentration of 10−5 M, was dissolved in the 5 wt% Cremophor emulsion for comparison in the ethanolic solution. The stability of such a self-assembly pigment–detergent nano-system is important in the light of its application on the commercial-scale. The presented results indicate the high stability of the pigment monomeric molecular organization in the nano-emulsion. During the storage in the dark, the half-lifetime was calculated as about 7 months. Additionally, based on the shape of absorption and fluorescence emission spectra, chlorophyll aggregation in the Cremophor EL aqueous solution along with the time was excluded. Moreover, the average size of detergent micelles as chlorophyll carriers was not affected after 70 days of the nano-system storage. Pigment stability against the moderate white light (0.1 mW) did not differ significantly from storage conditions in the dark. The photooxidation products, detected by occurrence of new absorption and fluorescence emission bands, was estimated on the negligible level. The stability of such a self-assembly pigment–detergent nano-system would potentially broaden the field of chlorophyll a (chl a) application in the food industry, medicine or artificial photosynthesis models.

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.

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