Search results for "Cytochrome f"
showing 10 items of 18 documents
Changes in the Content of Chlorophyll and Redox Components of the Thylakoid Membrane during Development and Senescence of Beech (Fagus sylvatica) Lea…
1995
Abstract Leaves from 145-year-old and 44-year-old beech trees were harvested during 1991-1993. Chlorophyll (Chl) and redox components of the thylakoid membrane, including P-700, cytochrome f (Cyt f) and D1 protein, were determined with the following results. Chl a + b, P-700 and Cyt f per unit of fresh weight (FW), dry weight (DW) and leaf area (LA) increase significantly during leaf development. This can be attributed to a massive membrane synthesis and new thylakoid formation in the cells. The Chl a/Chl b ratio decreases with the synthesis of Chl during the development of beech leaves and is reduced further with Chl breakdown in the stage of senescence. When expressed on the basis of Chl…
Isolation of chlorophyll-protein complexes and quantification of electron transport components in Synura petersenii and Tribonema aequale
1983
The chlorophyll-protein complexes of the yellow alga Synura petersenii (Chrysophyceae) and the yellow-green alga Tribonema aequale (Xanthophyceae) were studied. The sodiumdodecylsulfate/sodiumdesoxycholate solubilized photosynthetic membranes of these species yielded three distinct pigment-protein complexes and a non-proteinuous zone of free pigments, when subjected to SDS polyacrylamid gel electrophoresis. The slowest migrating protein was identical to complex I (CP I), the P-700 chlorophyll a-protein, which possessed 60 chlorophyll a molecules per reaction center in Tribonema and 108 in Synura. The zone of intermediate mobility contained chlorophyll a and carotenoids. The absorption spect…
Cytochrome F as Indicator for the Interaction of the Two Photosystems in the State 1 and State 2
1990
The transition of plants into a State 1 or a State 2 by an excess of PS I or PS II excitation was described by BONAVENTURA and MYERS [1]. Since the time of their investigations fluorometric methods gained increasing importance in analyzing the distribution of energy between the two photosystems [21. It was possible to correlate the altered energy balance to the phosphorylation of LHCII and it’s migration into non-appressed thylakoid membranes [31. However fluorescence measurements can give only indirect evidences that also changes in the activity of the two photosystems are produced by the changed energy distribution. A direct assessment of the photochemical variations during state transiti…
Measurements of manganese in thylakoids of Sinapis alba grown under high-light and low-light conditions.
1981
The manganese content of thylakoids and tissues was measured in leaves grown under high- and low-light conditions. Especially when grown in a nutrient medium enriched in manganese (20 μM), the thylakoids contained large amounts of manganese, which could be removed by EDTA washing without impairment of the Hill reaction. The unremovable content of manganese was almost the same in thylakoids from plants grown in nutrient media of normal (2 μM) and reduced (0.2 μM) manganese content. Up to this limit of manganese content, Hill activity did not seem to be impaired. 1.2 atoms Mn per 100 molecules chlorophyll were found in low-light thylakoids and 1.6 atoms Mn in high-light thylakoids. This is si…
The intensification of absorbance changes in leaves by light-dispersion
1979
In dispersive samples, like leaves, the absorbance of pigments is intensified. The intensification is due to a longer optical path through the dispersive sample. However, in chloroplast suspensions the optical path is not much longer than in clear solutions. The factor of intensification β (=the lengthening of the optical path) is calculated by comparing the absorbance of leaves and the absorbance of chloroplast suspensions with equal pigment-content. This method also includes the influence of possible sieve effects which could decrease absorbance. The measurements are carried out with high- and low-light leaves of different thickness and pigment content. The intensification of absorbance w…
Investigation on the Photosynthetic Membranes of Spruce Needles in Relation to the Occurrence of Novel Forest Decline II. The Content of QB-Protein, …
1988
In order to obtain an insight into the damage of thylakoid membranes of spruce (Picea abies) trees with damage of varying intensity, investigations were performed on the content of Qв-protein, cytochrome f, and P-700 in chloroplasts of spruce needles from apparently healthy and from damaged trees. Needles from the second and third needle year and the seventh whorl were chosen. The investigations were carried out in 1986 on a 20 to 25-year-old spruce plantation in the Hunsriick mountains and on an 80-year-old spruce plantation in the Westerwald mountains. In damaged trees an unequivocal decrease in the content of Qв-protein, cytochrome f, and P-700 was found, even in needle groups that appea…
The concentration of Cytochrome f and P700 in chlorophyll-deficient mutants of Chlorella fusca
1977
The ratio of Chlorophyll: Cytochrome f and of Chlorophyll: P700 (reaction center pigment in photosystem I) is essentially lower in chlorophyll-deficient mutants than in the normal green strain. On a dry weight basis, the mutants have the same or a higher content of redox enzymes than the normal form. The size of the photosynthetic unit of the mutants is 4 to 7 times smaller than that of the normal strains, due mainly to a deficiency of the light-harvesting chlorophyll-protein complex.
The Effect of Vanadium on the Content of Chlorophyll, P-700 and Cytochrome f at Different Light Intensities in Chlorella fusca
1980
Summary Cells of Chlorella fusca, were grown in liquid medium supplemented ,vith O.2% glucose and varied concentrations of vanadium both at 5 different light intensities and in the dark. \Vith increasing concentrations of vanadium the content of chlorophyll, P-700 and cytochrome f increased as well, each, however, in a different way. At the saturating concentration of 20 µg vanadium per litre the pigment content per dry weight was double as high as that of the vanadium-free control; the ratio of chlorophyll a/chlorophyll b increased from 2.1 to 2.9. The content of P-700 at saturating vanadium concentration was four times higher than that of the control when based on dry weight and double as…
Comparative Investigations on the Photosynthetic Electron Transport Chain of Spruce (Picea Abies) with Different Degrees of Damage in the Open Air
1988
Several components of the photosynthetic electron transport chain (P-700, cytochrome f, QB-protein) as well as the rate of electron transport and the chlorophyll content of the needles of spruce trees with different degrees of damage were investigated. The investigations were carried out in pair comparison at a location in the Hunsruck (West Germany). The rate of electron transport was determined as photoreduction of 2,6-dichlorophenolindophenol. Significant damage to the electron transport system is shown in the thylakoids of the damaged trees compared to the less severely damaged trees. In the spruce trees with more damage, the rates of electron transport are significantly lower. The inve…
Study of electrostatic potential surface distribution of wild-type plastocyaninSynechocystissolution structure determined by homonuclear NMR
2003
Plastocyanin is a small (∼10 kDa), type I blue copper protein that works as an electron donor to photosystem I from cytochrome f in both chloroplast systems and in some strains of cyanobacteria. Comparative studies of the kinetic mechanisms of plastocyanins in different organisms show that the electron transfer from photosystem I happens by simple collision in cyanobacteria but through a intermediate transition complex in green algae and superior plants. Previous work has proved that this effect cannot be explained by structural variations across the different plastocyanins but it can be explained by differences in the electrostatic potential distribution at the protein surface. In that cas…