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PubMed1980

Therapeutic effect of chlorophyll-a in the treatment of patients with chronic pancreatitis.

The favorable clinical effects of water-soluble form of chlorophyll-a in the treatment of patients with chronic relapsing pancreatitis are described. 1) 34 cases were treated with chlorophyll-a infusion and fairly favorable effect was obtained in 23 cases and some favorable effect, in 9 cases. 2) The most disgusting symptom of pancreatitis, the abdominal pain disappeared in a week or so with infusion of 5--20 mg of chlorophyll-a per day for 1--2 weeks, in all the effective cases. 3) Patients have become well controlled by intermittent administration of chlorophyll-a, even when they had recurrences. 4) 5 cases which had difficulty in the treatment by trasylol, were also successfully treated with chlorophyll-a. 5) In all the cases treated with chlorophyll-a, no unfavorable side-effect, such as of allergic, or photosensitive, or hepatotoxic nature, was hitherto observed.

Adult↗
PubMed2006

Identification and characterization of genes induced for anthocyanin synthesis and chlorophyll degradation in regenerated torenia shoots using suppression subtractive hybridization, cDNA microarrays, and RNAi techniques.

Anthocyanin synthesis and chlorophyll degradation in regenerated torenia (Torenia fournieri Linden ex Fourn.) shoots induced by osmotic stress with 7% sucrose were examined to identify the genes regulating the underlying molecular mechanism. To achieve this, suppression subtractive hybridization was performed to enrich the cDNAs of genes induced in anthocyanin-synthesizing and chlorophyll-degrading regenerated shoots. The nucleotide sequences of 1,388 random cDNAs were determined, and these were used in the preparation of cDNA microarrays for high-throughput screening. From 1,056 cDNAs analyzed in the microarrays, 116 nonredundant genes were identified, which were up regulated by 7% sucrose to induce anthocyanin synthesis and chlorophyll degradation in regenerated shoots. Of these, eight genes were selected and RNAi transformants prepared, six of which exhibited anthocyanin synthesis inhibition and/or chlorophyll degradation in their leaf discs. Notably, the RNAi transformants of the glucose 6-phosphate/phosphate translocator gene displayed inhibition both of anthocyanin synthesis and chlorophyll degradation in both leaf discs and regenerated shoots. There was also less accumulation of anthocyanin in the petals, and flowering time was shortened. The genes we identified as being up-regulated in the regenerated torenia shoots may help further elucidate the molecular mechanism underlying the induction of anthocyanin synthesis and chlorophyll degradation.

Anthocyanins↗
PubMed2006

Spatial and seasonal variations in chlorophyll-nutrient relationships in the shallow hypertrophic lake Manyas, Turkey.

Regression and correlation analyses were used to predict responses of phytoplankton biomass (chlorophyll) (microg L(-1)) to nitrate (NO(3)) (mg L(-1)), phosphate (PO(4)) (mg L(-1)) and ammonium (NH(4)) (mg L(-1)) dynamics in the shallow hypertrophic Lake Manyas, Turkey. Nutrient concentrations showed a descending gradient with distance, while chlorophyll concentrations showed an ascending gradient with the distance from the Siğirci Inlet to the Karadere Outlet. Higher nutrient concentrations did always not coincide with higher chlorophyll concentrations. The results showed that regression models developed using seasonal data were more accurate in predicting chlorophyll concentrations than those developed using the pooled data from whole year (based on R (2) and the difference between the measured and predicted values). The findings also revealed that within a single large shallow lake, chlorophyll-nutrient relationships might show significant variations spatially. The objective of this study was to determine the seasonal and spatial variations in the relationships between chlorophyll, nitrate, phosphate and ammonium in the shallow hypertrophic Lake Manyas, Turkey.

Chlorophyll↗
PubMed2005

Differential regulation of chlorophyll a oxygenase genes in rice.

Chlorophyll b is synthesized from chlorophyll a by chlorophyll a oxygenase. We have identified two genes (OsCAO1 and OsCAO2) from the rice genome that are highly homologous to previously studied chlorophyll a oxygenase (CAO) genes. They are positioned in tandem, probably resulting from recent gene duplications. The proteins they encode contain two conserved functional motifs - the Rieske Fe-sulfur coordinating center and a non-heme mononuclear Fe-binding site. OsCAO1 is induced by light and is preferentially expressed in photosynthetic tissues. Its mRNA level decreases when plants are grown in the dark. In contrast, OsCAO2 mRNA levels are higher under dark conditions, and its expression is down-regulated by exposure to light. To elucidate the physiological function of the CAO genes, we have isolated knockout mutant lines tagged by T-DNA or Tos17. Mutant plants containing a T-DNA insertion in the first intron of the OsCAO1 gene have pale green leaves, indicating chlorophyll b deficiency. We have also isolated a pale green mutant with a Tos17 insertion in that OsCAO1 gene. In contrast, OsCAO2 knockout mutant leaves do not differ significantly from the wild type. These results suggest that OsCAO1 plays a major role in chlorophyll b biosynthesis, and that OsCAO2 may function in the dark.

Chlorophyll↗
PubMed1975

Further results on the photoactive chlorophyll aII in photosynthesis.

1. The flash-induced difference spectra of chlorophyll aII in untreated and in heat-treated spinach chloroplasts are presented. 2. Heat-treatment leads to an increase of the half-life of the chlorophyll aII absorbance changes. After the addition of hydroquinone plus sodium ascorbate the half-life of the chlorophyll aII reaction returns nearly to the value in untreated chloroplasts. 3. In digitonin-treated chloroplasts, or in the presence of histone, the chlorophyll aII activity is low when the electron acceptor is benzylviologen and high when ferricyanide is used. 4. The half-life of the chlorophyll aII reaction depends on the temperature of the reaction mixture. The activation energy of the chlorophyll aII reaction is about 7.5 kcal/mol. 5. From the experimental results we conclude that in heat-treated (and in Tris-washed and aged) chloroplasts the linear electron flow in Photosystem II is replaced by a cyclic one, which is sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea.

Chlorophyll↗
PubMed1975

[Independence of special forms of chloeophyll a and chlorophyll holochromes].

Zea mays L. seedlings were cultivated for 10 days with submission to 4 s illumination periods interspersed with dark periods varying in length from 30 min to 6 h depending on the lot analyzed. The results show that, for the case in which the dark periods were shorter than 1 h, the relative proportions of different spectroscopic chlorophyll forms (maxima at 662, 670, 677.5, and 684 nm) were constant. For longer durations of darkness between illuminations, the relative proportion of the form Da670 increases, while that of Ca684 diminishes with the length of darkness; to a lesser extent, the relative proportion of Ca662 increases and a form Ca692 disappears. A scheme is proposed to explain the evolution of the relative proportions of the different spectral forms. The different chlorophyll holochromes present in the chloroplasts were also analysed. If the dark period was longer than 1 h, chlorophyll was associated with peptide chains of molecular weights 21 000 and 29 000. If the dark period was shorter than 1 h chlorophyll was associated with four peptide chains of molecular weights 21 000, 25 000, 29 000 and 70 000. The results taken together demonstrate that a given spectral chlorophyll a form cannot be associated with a definite chlorophyll holochrome.

Binding Sites↗
PubMed1976

The study of the primary photoprocesses in photosystem I of chloroplasts. Recombination luminescence, chlorophyll triplet state and triplet-triplet annihilation.

The dependence of the delayed luminescence of Photosystem I on the state of the reaction centers has been studied. Light flash induces a charge separation in the centers: P-700-P-430 hv in equilibrium P-700+-P-430-. Dark recombination of charges is accompanied by the recombination luminescence with tau1/2 congruent to 20ms. If the centers are in the P-700-P-430- state or if P-430 is inactivated by heat, then flashing of Photosystem I generates the triplet state chlorophyll with tau1/2 congruent to 0.5 ms. The triplet state has been measured by the delayed fluorescence of chlorophyll at 20 degrees C and 77 degrees K and by the chlorophyll phosphorescence at 77 degrees K. The delayed fluorescence at 20 degrees C arises from the thermal activation of the triplet state up to the excited singlet level of chlorophyll and at 77 degrees K it is due to triplet-triplet annihilation. The quantum yield of the triplet formation, estimated by a comparison of the light saturation curves of delayed fluorescence at 20 degrees C and of P-700 photooxidation under the same experimental (optical) conditions, is approximately 0.9 of the P-700+ yield. Only one triplet of chlorophyll can be generated per P-700. Under heat inactivation of P-430 the triplet formation is not observed when P-700 is oxidized. It is assumed that the triplet-triplet annihilation at 77 degrees K is related with the strong interaction between the chlorophyll molecules in the pigment complex of Photosystem I. The possibility of a triplet participation in the primary processes of photosynthesis is discussed.

Chlorophyll↗
PubMed1978

Functional and structural organization of chlorophyll in the developing photosynthetic membranes of Euglena gracilis Z. II. Formation of system II photosynthetic units during greening under optimal light intensity.

The relationships between light-harvesting chlorophyll and reaction centers in Photosystem II were analyzed during the chloroplast development of dark-grown, non-dividing Euglena gracilis Z. Comparative measurements included light saturation of photosynthesis, oxygen evolution under flashing-light and fluorescence induction. The results obtained can be summarized as follows: (1) Photosystem II photocenters are formed in parallel with chlorophyll synthesis, but after a long lag phase. (2) As a consequence, the chlorophyll reaction center ratio (Emerson's type photosynthetic unit) decreases during greening. (3) This decrease is accompanied by considerable changes in the energy transfer and trapping properties of Photosystem II. Most of the initially synthesized chlorophylls are inactive in the transfer of excitations to active photochemical centers and are shared among newly formed Photosystem II photocenters; as a consequence, the number of chlorophylls functionally connected to each Photosystem II photocenter decreases and cooperatively between these centers appears. Results are discussed in terms of chlorophyll organization in developing photosynthetic membranes with reference to the lake or puddle models of photosynthetic unit organization.

Chlorophyll↗
PubMed1981

Chlorophyll composition of photosystems II alpha, II beta and I in tobacco chloroplasts.

The antenna composition of the Photosystems II alpha, II beta and I was studied in tobacco chloroplasts. Absorbance spectra, recorded at 4 K, were analyzed for the wild type and the mutants Su/su and Su/su var. Aurea, containing higher concentrations of the photosystems. With chloroplasts of Su/su we measured the action spectra of the three photosystems from 625 to 690 nm. Above 675 nm absorption by Photosystem I dominated. This system had a maximum at 678 nm and a shoulder at 660 nm. Of the long-wavelength chlorophyll a forms, absorbing at 690, 697 and 705 nm at 4 K, which are generally assigned to Photosystem I, the 697 nm form occurred in an amount of four molecules per reaction center of Photosystem I in each type of chloroplast. The Photosystem II alpha spectrum was characterized by maxima at 650 and 672 nm, showing clearly the participation of the chlorophyll a and b containing light-harvesting complex. In the mutants the light-harvesting complex has a chlorophyll a to chlorophyll b ratio of more than 1; the amount of the 672 nm chlorophyll a was normal, whereas the amount of chlorophyll b was markedly decreased in the mutants relative to the wild type. The Photosystem II beta spectrum mainly consisted of a band at 683 nm.

Chlorophyll↗
PubMed1984

Organization of the photosynthetic apparatus of the chlorina-f2 mutant of barley using chlorophyll fluorescence decay kinetics.

The time-resolved chlorophyll fluorescence emission of higher plant chloroplasts monitors the primary processes of photosynthesis and reflects photosynthetic membrane organization. In the present study we compare measurements of the chlorophyll fluorescence decay kinetics of the chlorophyll-b-less chlorina-f2 barley mutant and wild-type barley to investigate the effect of alterations in thylakoid membrane composition on chlorophyll fluorescence. Our analysis characterizes the fluorescence decay of chlorina-f2 barley chloroplasts by three exponential components with lifetimes of approx. 100 ps, 400 ps and 2 ns. The majority of the chlorophyll fluorescence originates in the two faster decay components. Although photo-induced and cation-induced effects on fluorescence yields are evident, the fluorescence lifetimes are independent of the state of the Photosystem-II reaction centers and the degree of grana stacking. Wild-type barley chloroplasts also exhibit three kinetic fluorescence components, but they are distinguished from those of the chlorina-f2 chloroplasts by a slow decay component which displays cation- and photo-induced yield and lifetime changes. A comparison is presented of the kinetic analysis of the chlorina-f2 barley fluorescence to the decay kinetics previously measured for intermittent-light-grown peas (Karukstis, K. and Sauer, K. (1983) Biochim. Biophys. Acta 725, 384-393). We propose that similarities in the fluorescence decay kinetics of both species are a consequence of analogous rearrangements of the thylakoid membrane organization due to the deficiencies present in the light-harvesting chlorophyll a/b complex.

Chlorophyll↗
PubMed1988

Purification and characterization of an iron stress-induced chlorophyll-protein from the cyanobacterium Anacystis nidulans R2.

An Anacystis nidulans R2 chlorophyll-protein associated with Photosystem II in iron-stressed cells (Pakrasi, H.B., Riethmann, H.C. and Sherman, L.A. (1985) Proc. Natl. Acad. Sci. USA 82, 6903-6907) has been biochemically purified and characterized. Anion exchange chromatography of dodecyl-beta-D-maltoside-solubilized membranes from iron-deficient cells was used to recover this chlorophyll-protein (termed CPVI-4) in high yield and in a relatively native state. CPVI-4 has a room temperature absorption maximum at 671 nm, a 77 K chlorophyll fluorescence peak at 681 nm, and contains polypeptides of 36, 34 and 12 kDa. The 36 and 34 kDa polypeptides are associated with chlorophyll on mildly denaturing acrylamide gels of purified CPVI-4, although only the 34 kDa protein is immunoreactive with antisera elicited against the gel-purified chlorophyll-protein. Immunoblotting experiments with dodecyl-beta-D-maltoside-solubilized membrane fractions and purified CPVI-4 indicate that CPVI-4 does not contain previously identified Photosystem II core proteins. CPVI-4 likely functions as a light-harvesting antenna complex in iron-starved cells (where phycobilisomes are absent or diminished) and, in addition, may contribute chlorophyll to the reaction center complexes during their assembly in the early stages of recovery from iron stress.

Chlorophyll↗
PubMed2004

Chlorophyll production from Spirulina platensis: cultivation with urea addition by fed-batch process.

The cyanobacterium Spirulina platensis is an attractive alternative source of the pigment chlorophyll, which is used as a natural color in food, cosmetic, and pharmaceutical products. In this work, the influence of the light intensity and urea supplementation as a nitrogen source using fed-batch cultivation for S. platensis growth and chlorophyll content was examined. Cultivations were carried out in 5 l open tanks, at 30+/-1 degrees C. Response surface methodology was utilized for analysis of the results, and models were obtained for biomass productivity, nitrogen-cell conversion factor and chlorophyll productivity. The best cellular growth was observed with 500 mg/l of urea at a light intensity of 5600 lx, whereas the highest concentration of chlorophyll in the biomass was observed with 500 mg/l of urea at a light intensity of 1400 lx. Overall, the best chlorophyll productivity was observed with 500 mg/l of urea at a light intensity of 3500 lx, providing the optimal balance between the cellular growth and the biomass chlorophyll content.

Analysis of Variance↗
PubMed2001

Modification of photosystem I reaction center by the extraction and exchange of chlorophylls and quinones.

The photosystem (PS) I photosynthetic reaction center was modified thorough the selective extraction and exchange of chlorophylls and quinones. Extraction of lyophilized photosystem I complex with diethyl ether depleted more than 90% chlorophyll (Chl) molecules bound to the complex, preserving the photochemical electron transfer activity from the primary electron donor P700 to the acceptor chlorophyll A(0). The treatment extracted all the carotenoids and the secondary acceptor phylloquinone (A(1)), and produced a PS I reaction center that contains nine molecules of Chls including P700 and A(0), and three Fe-S clusters (F(X), F(A) and F(B)). The ether-extracted PS I complex showed fast electron transfer from P700 to A(0) as it is, and to FeS clusters if phylloquinone or an appropriate artificial quinone was reconstituted as A(1). The ether-extracted PS I enabled accurate detection of the primary photoreactions with little disturbance from the absorbance changes of the bulk pigments. The quinone reconstitution created the new reactions between the artificial cofactors and the intrinsic components with altered energy gaps. We review the studies done in the ether-extracted PS I complex including chlorophyll forms of the core moiety of PS I, fluorescence of P700, reaction rate between A(0) and reconstituted A(1), and the fast electron transfer from P700 to A(0). Natural exchange of chlorophyll a to 710-740 nm absorbing chlorophyll d in PS I of the newly found cyanobacteria-like organism Acaryochloris marina was also reviewed. Based on the results of exchange studies in different systems, designs of photosynthetic reaction centers are discussed.

Chlorophyll↗
PubMed2002

Electric field effects on red chlorophylls, beta-carotenes and P700 in cyanobacterial Photosystem I complexes.

We have probed the absorption changes due to an externally applied electric field (Stark effect) of Photosystem I (PSI) core complexes from the cyanobacteria Synechocystis sp. PCC 6803, Synechococcus elongatus and Spirulina platensis. The results reveal that the so-called C719 chlorophylls in S. elongatus and S. platensis are characterized by very large polarizability differences between the ground and electronically excited states (with Tr(Deltaalpha) values up to about 1000 A(3) f(-2)) and by moderately high change in permanent dipole moments (with average Deltamu values between 2 and 3 D f(-1)). The C740 chlorophylls in S. platensis and, in particular, the C708 chlorophylls in all three species give rise to smaller Stark shifts, which are, however, still significantly larger than those found before for monomeric chlorophyll. The results confirm the hypothesis that these states originate from strongly coupled chlorophyll a molecules. The absorption and Stark spectra of the beta-carotene molecules are almost identical in all complexes and suggest similar or slightly higher values for Tr(Deltaalpha) and Deltamu than for those of beta-carotene in solution. Oxidation of P700 did not significantly change the Stark response of the carotenes and the red antenna states C719 and C740, but revealed in all PSI complexes changes around 700-705 and 690-693 nm, which we attribute to the change in permanent dipole moments of reduced P700 and the chlorophylls responsible for the strong absorption band at 690 nm with oxidized P700, respectively.

Chlorophyll↗
PubMed2002

Relevance of the diastereotopic ligation of magnesium atoms of chlorophylls in Photosystem I.

The central magnesium (Mg) atoms of natural occurring tetrapyrroles such as chlorophylls (Chls) and bacteriochlorophylls (BChls) are typically five-coordinated, a fact which leads to the formation of diastereoisomers if the Mg-ligand bond is stable on the time scale of the observation method. This possibility has only been briefly addressed before in a CD-study of BChl c aggregates [T.S. Balaban, A.R. Holzwarth, K. Schaffner, J. Mol. Struct. 349 (1995) 183]. On the basis of the chlorophyll-protein complex photosystem I (PSI), which has recently been characterized by single crystal crystallography [P. Jordan, P. Fromme, H.T. Witt, O. Klukas, W. Saenger, N. Krauss, Nature 411 (2001) 909], we find that chlorophyll a molecules are much more frequently bound by the protein matrix from one side (anti) than the other one (syn) in a ratio of 82:14, which corresponds to a significant DeltaDeltaG value of 4.3 kJ/mol. Syn and anti denote the orientation of the Mg-ligand with respect to the 17-propionic acid esterified by phytol. Furthermore, by parallel sequence analysis we find that the binding sites for both syn and anti chlorophylls have been strongly conserved during evolution-a fact which stresses the nonrandom manner in which chlorophylls are bound by the apoprotein in antenna complexes, in order to exert efficiently their light harvesting function and energy funnelling. Most remarkably, all the syn chlorophylls are part of the inner core antenna system. Results from semiempirical quantum mechanical and detailed exciton coupling calculations allow us to speculate on the functional relevance of the diasteretopicity for PSI functioning.

Amino Acid Sequence↗
PubMed2000

Excitation transfer in the peridinin-chlorophyll-protein of Amphidinium carterae.

Peridinin-chlorophyll-protein (PCP) is a unique light-harvesting protein that uses carotenoids as its primary light-absorbers. This paper theoretically investigates excitation transfer between carotenoids and chlorophylls in PCP of the dinoflagellate Amphidinium carterae. Calculations based on a description of the electronic states of the participating chromophores and on the atomic level structure of PCP seek to identify the mechanism and pathways of singlet excitation flow. After light absorption the optically allowed states of peridinins share their electronic excitation in excitonic fashion, but are not coupled strongly to chlorophyll residues in PCP. Instead, a gateway to chlorophyll Q(y) excitations is furnished through a low-lying optically forbidden excited state, populated through internal conversion. Carbonyl group and non-hydrogen side groups of peridinin are instrumental in achieving the respective coupling to chlorophyll. Triplet excitation transfer to peridinins, mediated by electron exchange, is found to efficiently protect chlorophylls against photo-oxidation.

Animals↗
PubMed1978

Use of immobilized light-harvesting chlorophyll a/b protein to study the stoichiometry of its self-association.

D. J. Davis & E. L. Gross (1976) Biochim. Biophys. Acta 449, 554-564 previously observed that the light-harvesting chlorophyll a/b protein or chlorophyll protein complex II self-associated as determined by ultracentrifugation. We have determined the stoichiometry of complex formation by immobilizing the monomer on ethylenediamine-Sepharose 4B and determing the ability of immobilized protein to bind the free protein. The amount of soluble protein bound to the immobilized protein increased as the concentration of soluble protein increased. The binding was maximal between pH 7 and 8. The maximum binding was three molecules bound per one molecule of protein immobilized. These results indicate that a tetramer is the intrinsic structural unit of the light-harvesting chlorophyll a/b protein in the chloroplast membrane. Upon complex formation, the chlorophyll fluorescence was decreased without any spectral change. The maximum binding was approximately doubled upon addition of 0.5 mM CaCl2 whereas 5 mM NaCl had no effect. Addition of CaCl2 had no effect on the fluorescence of the monomer. The light-harvesting chlorophyll a/b protein can be isolated from a sodium lauryl sulfate extract of chloroplasts by affinity chromatography using the immobilized light-harvesting chlorophyll a/b protein.

Cations↗
PubMed2005

Spectroscopic studies of photosystem II in chlorophyll d-containing Acaryochloris marina.

Photosystem II (PSII) electron transfer (ET) in the chlorophyll d-containing cyanobacterium Acaryochloris marina (A. marina) was studied by time-resolved electron paramagnetic resonance (EPR) spectroscopy at room temperature, chlorophyll fluorescence, and low-temperature optical spectroscopy. To maximize the ability to measure PSII ET in the intact cells of this organism, growth conditions were optimized to provide the highest specific O(2) activity and the instrumental parameters for the EPR measurements of tyrosine Z (Y(Z)) reduction were adjusted to give the best signal-to-noise over spectral resolution. Analysis of the Y(Z)(*) reduction kinetics revealed that ET to the oxygen-evolving complex on the donor side of PSII in A. marina is indistinguishable from that in higher plants and other cyanobacteria. Likewise, the charge recombination kinetics between the first plastoquinone acceptor Q(A) and the donor side of PSII monitored by the chlorophyll fluorescence decay on the seconds time scale are not significantly different between A. marina and non-chlorophyll d organisms, while low-temperature optical absorption spectroscopy identified the primary electron acceptor in A. marina as pheophytin a. The results indicate that, if the PSII primary electron donor in A. marina is made up of chlorophyll d instead of chlorophyll a, then there must be very different interactions with the protein environment to account for the ET properties, which are similar to higher plants and other cyanobacteria. Nevertheless, the water oxidation mechanism in A. marina is kinetically unaltered.

Bacterial Proteins↗