共查询到20条相似文献,搜索用时 15 毫秒
1.
During growth under far-red (>650 nm) light, Anacystis nidulans accumulates protochlorophyllide to concentrations about one-tenth of the chlorophyll. From whole cell fluorescence spectra, protochlorophyll(ide) was identified also in another blue-green, and in a red, alga grown in far-red light. 相似文献
2.
In an attempt to solve the controversy about the evaluation of the molar absorption coefficient of PChl(ide), this coefficient is estimated in this work by using an original experimental approach. The calculated molar absorption coefficient of PChl(ide) is 30.4.103 1 mole–1 cm–1 at 626 nm in acetone 80%; it is close to that derived from the specific absorption coefficient of Koski and Smith when assuming that the pigment extracted by these authors was the esterified pigment: PChl. Sets of equations for the quantification of Chl(ide) a, Chl b and PChl(ide) in 80% acetone extracts are derived.Abbreviations PChl(ide) protochlorophyll(ide) - Chl(ide) chlorophyll(ide) 相似文献
3.
The phototransformation of protochlorophyll(ide) (Pchl(ide)) to chlorophyll(ide) (Chl(ide)) can be demonstrated in a proplastid fraction from Euglena gracilis Klebs var. bacillaris Cori if appropriate conditions are employed. Pigments were measured fluorometrically in acetone extracts of cell or organelles. Pchl(ide) and the phototransformation to Chl(ide) are at their highest levels in cells grown in darkness on normal or low vitamin B12-containing medium (pH 3.5) to the late exponential phase (1.2–1.4 × 106 cells ml?1). Late exponential cells on low B12 medium yield a proplastid fraction that contains Pchl(ide) which is phototransformed to Chl(ide) when illuminated with red light (5.6 W m?2 for 4 min) in the presence of 10 mM Hepes, 20 mM TES, 0.5 mM potassium phosphate (pH 7.4), 70 mM sorbitol, 5 mM DTT, 5 mM ATP, 5 mM fructose-1, 6-bisphosphate, 10 mM malate and 2 mM MgCl2; intact organelles appear to be involved since deletion of osmoticum gives a lower activity, and addition of NAD(P)H is without effect. Phototransformation of Pchl(ide) to Chl(ide) in red light shows Bunsen-Roscoe reciprocity between fluence rate and duration of illumination. Although mitochondria are present, they do not appear to be involved since inhibitors of respiration and uncouplers of oxidative phosphorylation fail to block the phototransformation. The percentage phototransformation of Pchl(ide) to Chl(ide) in late exponential normal B12 cells is 61 ± 10, and is 52 ± 3 in low B12 cells. About 67% of the activity in low B12 cells is recovered in the proplastid fraction incubated with the complete incubation mixture in saturating light. In both types of cells and in the proplastid fraction, the stoichiometry of conversion of Pchl(ide) to Chl(ide) is about 1:1 (mol/mol). 相似文献
4.
A stable, soluble, and photoactive protochlorophyll(ide) complex has been extracted from dark-grown barley (Hordeum vulgare L.) leaves with buffer containing saponin and glycerol. After ammonium sulfate precipitation, the redissolved pigment complex was partially purified by chromatography on Sephadex gels in the presence of saponin. With the assumptions that the pigment complex from barley has the same shape and density as the proteins used for calibration, its molecular weight is 63,000. Photoactive protochlorophyll(ide) complex isolated from bean (Phaseolus vulgaris L.) and chromatographed by the same procedures has an aparent molecular weight of 100,000 or greater. No chromatographic separation of photoactive and inactive protochlorophyll(ide) complexes was observed. Photoconversion of protochlorophyll(ide) to chlorophyll(ide) did not change the chromatographic behavior of the pigment complex. 相似文献
5.
In an attempt to solve the controversy about the evaluation of the molar absorption coefficient of PChl(ide), this coeffecient is estimated in this work by using an original experimental approach. The calculated molar absorption coefficient of PChl(ide) is 30.4.103 l mole-1 cm-1 at 626 nm in acetone 80%; it is close to that derived from the specific absorption coefficient of Koski and Smith when assurning that the pigment extracted by these authors was the esterified pigment: PChl. Sets of equations for the quantification of Chl(ide) a, Chl b and PChl(ide) in 80% acetone extracts are derived. 相似文献
6.
Using spectral methods, the biosynthesis of protochlorophyll(ide) and chlorophyll(ide) in green plant leaves was studied. The main chlorophyll precursors in the green leaves (as in etiolated leaves) were photoactive photocholorophyll(ide) forms Pchl(ide)655/650(448) and Pchl(ide)653/648(440). The contributions into Chl biosynthesis of the shorter-wavelength precursor forms ,which were accumulated in darkened green leaves as well, were completely absent (of Pchl(ide) 633/628(440)) or insignificant (of Pchl(ide)642/635(444)). 相似文献
7.
8.
Cells of Euglena gracilis Klebs var. bacillaris Cori growingin darkness on a complete medium have small undifferentiatedproplastids. On transfer to an incomplete (resting) medium indarkness, the cells cease division within 72 h. During thistime the proplastid expands and several prothylakoids and prolamellarbodies develop even though phototransformable protochlorophyll(ide)[PT-Pchl(ide)] is decreasing. As PT-Pchl(ide) decreases furtherand reaches a stable plateau after 45 more days in darkness,the proplastid structure becomes highly reduced. Forty minutesof light plus a one h dark period, or addition of glutamateor malate for 7 h does not change the proplastid structure significantlyeven though PT-Pchl(ide) returns to the level found in growingcells. Upon prolonged incubation in darkness after light treatment(72 h) an expanded proplastid containing prothylakoids, prolamellarbodies and membrane whorls with mitochondria in close associationis seen; most of the cellular paramylum is lost during thisperiod leaving cavities in the cytoplasm. Without light, prolongedincubation in darkness (72 h) with malate leads to accumulationof cellular paramylum but no change in proplastid structurewhile prolonged treatment with glutamate (72 h) allows the formationof a few prothylakoids but no prolamellar bodies. 1Supported by Grants GM 14595 from the National Institutes ofHealth.2Permanent address: Department of Microbiology, Tokyo MedicalCollege, 6-1-1 Shinjuku, Tokyo 160, Japan.3Abraham and Etta Goodman Professor of Biology. (Received July 23, 1983; Accepted September 22, 1983) 相似文献
9.
The assignment is presented for the principal phosphorescence bands of protochlorophyll(ide), chlorophyllide and chlorophyll in etiolated and greening bean leaves measured at -196°C using a mechanical phosphoroscope. Protochlorophyll(ide) phosophorescence spectra in etiolated leaves consist of three bands with maxima at 870, 920 and 970 nm. Excitation spectra show that the 870 nm band belongs to the short wavelength protochlorophyll(ide), P627. The latter two bands correspond to the protochlorophyll(ide) forms, P637 and P650. The overall quantum yield for P650 phosphorescence in etiolated leaves is near to that in solutions of monomeric protochlorophyll, indicating a rather high efficiency of the protochlorophyll(ide) triplet state formation in frozen plant material. Short-term (2–20 min) illumination of etiolated leaves at the temperature range from -30 to 20°C leads to the appearance of new phosphorescence bands at about 990–1000 and 940 nm. Judging from excitation and emission spectra, the former band belongs to aggregated chlorophyllide, the latter one, to monomeric chlorophyll or chlorophyllide. This indicates that both monomeric and aggregated pigments are formed at this stage of leaf greening. After preillumination for 1 h at room temperature, chlorophyll phosphorescence predominates. The spectral maximum of this phosphorescence is at 955–960 nm, the lifetime is about 2 ms, and the maximum of the excitation spectrum lies at 668 nm. Further greening leads to a sharp drop of the chlorophyll phosphorescence intensity and to a shift of the phosphorescence maximum to 980 nm, while the phosphorescence lifetime and a maximum of the phosphorescence excitation spectrum remains unaltered. The data suggest that chlorophyll phosphorescence belongs to the short wavelength, newly synthesized chlorophyll, not bound to chloroplast carotenoids. Thus, the phosphorescence measurement can be efficiently used to study newly formed chlorophyll and its precursors in etiolated and greening leaves and to address various problems arising in the analysis of chlorophyll biosynthesis.Abbreviations Pchl
protochlorophyll and protochlorophyllide
- Chld
chlorophyllide
- Chl
chlorophyll 相似文献
10.
Protochlorophyll(ide) was isolated from dark-grown wild typeand mutant C-2A' cells of Scenedesmus obliquus after dark incubationwith 5-aminolevulinate. Proto-chlorophyll(ide) was detectedin mutant cells grown heterotrophically at 29°C or at 21°C.At the latter temperature chlorophyll synthesis was significant.Regulation of chlorophyll synthesis in algae is discussed. 1Present address: Laboratory of Chemistry, Faculty of Medicine,Teikyo University, Otsuka, Hachioji, Tokyo 192-03, Japan. (Received July 14, 1980; ) 相似文献
11.
Chlorophyll Synthesis from Protochlorophyll(ide) in Chill-Stressed Maize (Zea mays L.) 总被引:1,自引:0,他引:1
Illumination of aetiolated maize at temperatures lower than20 °C results in negligible accumulation of chlorophyll.Illumination of leaf tissue, previously incubated in 10 molm3 ALA in darkness, shows only a slight conversion ofprotochlorophyll(ide) to chlorophyll a and b at temperaturesless than 20 °C. A refined procedure for measuring photosynthesisby photo-acoustic spectroscopy in leaves that differ in chlorophyllcontent is presented. Studies of photosynthesis in aetiolatedseedlings illuminated at different temperatures by photo-acousticspectroscopy suggests that impairment of the chlorophyll pathwayis paralleled by an aberrant development of the thylakoid membrane. Key words: Protochlorophyll(ide), temperature, photo-acoustic spectroscopy, membrane biogenesis 相似文献
12.
The protochlorophyll(ide) forms and plastid ultrastructure were investigated in hypocotyls of dark-grown seedlings of kidney bean ( Phaseolus vulgaris L. cv. Brede zonder draad). By deconvolution of the fluorescence emission spectra into Gaussian components three protochlorophyll(ide) forms were found with maxima at 633, 642 and 657 nm, respectively. The ratio of protochlorophyll(ide) emitting at 657 nm to protochlorophyll(ide) emitting at 633 nm decreased downwards the hypocotyl. The gradient was established already after 4 days in dark-grown Phaseolus and was also seen in hypocotyls of 7-day-old dark-grown plants of 8 other species. Ultrastructural observations revealed a plastid developmental sequence along the hypocotyl. Plastids in the upper parts of the hypocotyl contained prolamellar bodies typical of etiolated leaves while those in the lower parts contained only stroma lamellae. Immunological detection of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33) on nitrocellulose membranes after sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) indicated the occurrence of the enzyme in upper, middle and lower sections of hypocotyls and in the root tips. 相似文献
13.
The kinetics of photoconversion of protochlorophyll(ide) to chlorophyll(ide) a were investigated in dark-grown barley leaves and in a preparation of protochlorophyll holochrome subunits. In the subunits the conversion obeyed first-order kinetics. This indicates that the excitation of protochlorophyll(ide), energy loss through deexcitation, and the reduction of excited protochlorophyll(ide) are all reactions that follow first-order kinetics with respect to protochlorophyll(ide) in protochlorophyll holochrome subunits.In contrast, photoconversion in leaves obeyed neither first- nor second-order kinetics. This prompted the postulation of an additional route within macromolecular units of protochlorophyll holochrome, whereby energy is lost from excited protochlorophyll(ide) by a reaction that is not first order. Such a process might be energy transfer from excited protochlorophyll(ide) to newly-formed chlorophyll(ide) a.A dynamic model describing photoconversion in macromolecular units was derived. The model is consistent with the observed progress of photoconversion in barley leaves and in protochlorophyll holochrome subunits from barley.Determinations of the quantum yield of photoconversion in protochlorophyll holochrome subunits gave values of 0.4–0.5 molecules · quantum?1. Estimates of the initial quantum yield of the photoconversion process in leaves fell into the same range. The dynamic model allows predictions on the progressively decreasing quantum yield as the photoconversion proceeds in macromolecular units. 相似文献
14.
V P Shedbalkar I M Ioannides C A Rebeiz 《The Journal of biological chemistry》1991,266(26):17151-17157
The occurrence of protochlorophyllide b and protochlorophyllide b phytyl ester in green plants is described. The chemical structure of protochlorophyllide b phytyl ester was established by proton nuclear magnetic resonance, fast atom bombardment mass spectroscopic analysis, and chemical derivatization coupled to electronic spectroscopic analysis. The macrocycles of protochlorophyll(ide) b are identical to those of conventional protochlorophyll(ide) except for the presence of a formyl group instead of a methyl group at position 3 of the macrocycles. They differ from chlorophyll(ide) b by the presence of an oxidized double bond at positions 7 and 8 of the macrocycles. The trivial name protochlorophyll(ide) b is proposed to differentiate these two tetrapyrroles from conventional protochlorophyll(ide), which in turn will be referred to as protochlorophyll(ide) a. Protochlorophyll(ide) b appears to be widely distributed in green plants. Its molar extinction coefficients in 80% acetone and diethyl ether are reported. The impact of this discovery on the heterogeneity of the chlorophyll a and b biosynthetic pathways is discussed. 相似文献
15.
B. M. STUMMANN 《Physiologia plantarum》1978,43(3):173-176
Earlier work has shown that protochlorophyll(ide) holochrome is associated with the prolamellar body membranes in etioplasts of barley (Hordeum vulgare L.), and that this pigment-protein complex can be extracted in a stable, photoactive form by the use of saponin. For future work it would be advantageous if saponin, a detergent mixture, could be replaced by a single, well-characterized substance. The spectral characteristics of holochrome extracted with 10 ionic and nonionic detergents were compared to those of the holochrome extracted with saponin. Mulgofen BC-840 and digitonin extracted significant amounts of photoactive protochlorophyll(ide) holochrome, but this activity was highly labile, and no adequate substitute for saponin was found. Thus the stabilizing and solubilizing function of saponin is not simply related to the general properties of detergents. 相似文献
16.
Three protochlorophyll(ide)-binding proteins were separatedfrom an SDS-solubilized extract of etiolated leaves of kidneybean (Phaseolus vulgaris) by size-exclusion, high-performanceliquid chromatography. The molecular masses of these pigmentproteins were determined to be 84, 38 and 25 kDa. In the illuminatedsample, the peak areas of the 84 and 38 kDa proteins decreased,indicating phototransformation of the pigments in these proteins. (Received December 17, 1984; Accepted February 12, 1985) 相似文献
17.
Albert Kahn 《Physiologia plantarum》1983,59(1):99-102
To allay doubt about how to calculate molar extinction eoeffieients from the specific absorption coefficients of protoehlorophyll(ide), dark-grown leaf segments and saponin protochlorophyll(ide) holochrome subunits frotn barley ( Hordeum vulgare L.) and cotyledons of cucumber ( Cucumis sativus L.) were extracted with acetone without or following prior, brief illumination. Absorbance data and eoeffieients of chlorophyll a were used to derive extinetion eoeffieients of protoehlorophyll(ide); 626 nm (range: 30 to 35 1 mmol-1 cm-1 ) without recourse to published coefficients c protochlorophyll(ide). These results combined with evaluation of how the origin; coefficients were obtained, argue for using the molecular weight of protochlorophy rather than protochlorophyllide to calculate molar extinction eoeffieients from th specific absorption coefficients. 相似文献
18.
It has been found that at low temperatures (77K–153K) a long-lived (at these temperatures) singlet ESR signal induced by intensive light appears in etiolated leaves of plants and in model systems including both the monomeric and aggregated protochlorophyll.Comparison of the results of ESR, fluorescence and absorption spectra measurements made it possible to suggest that at the initial stages of the protochlorophyll(ide) photoreduction process at least two paramagnetic non-fluorescent intermediates are formed, one of which seems to be identical to the previously found intermediate with absorption maximum at 690 nm. On the strength of the obtained results a conclusion can be drawn that photoreduction of the semi-isolated double-c=c-bond of the chlorophyll precursor molecule in etiolated leaves and in model systems is actualized via at least two stages of free radicals formation. A scheme of the primary reactions of chlorophyllide biosynthesis has been proposed. 相似文献
19.
Yeast mutant defective in phosphatidylserine synthesis 总被引:22,自引:0,他引:22
Phospholipid biosynthesis in a mutant of Saccharomyces cerevisiae (cho1) which lacks phosphatidylserine (Atkinson, K. D., Jensen, B., Storm, E., Kolat, A. I., Henry, S. A. & Fogel, S. (1980) J. Bacteriol. 141, 558-564) has been examined. The ability of cells of this strain to synthesize phosphatidylserine in vitro in a cell-free system is reduced at least 10-fold, whereas other phospholipid-synthesizing activities are present at normal or slightly elevated levels. While all phospholipid biosynthetic activities, except phosphatidylserine synthesis, can be demonstrated in vitro in the cho1 mutant, the entire pattern of phospholipid synthesis, accumulation, and turnover in vivo is distorted. Phosphatidylinositol synthesis is elevated, as is phosphatidylcholine synthesis. In addition, the turnover of phosphatidylcholine is more rapid in the cho1 mutant. The cho1 mutant appears to use almost exclusively the alternative pathway described by Kennedy and Weiss (1956) J. Biol. Chem. 222, 193-214) for the production of phosphatidylethanolamine and phosphatidylcholine, bypassing phosphatidylserine as an intermediate. 相似文献
20.
Rice (Oryza sativa L. cv. Yamabiko) seedlings germinated underwater for 5 days contained small amounts of heme a and protohemebut no protochlorophyll(ide) [Pchl(ide)]. Levels of hemes andPchl(ide) increased rapidly upon transfer to air. When expressedin terms of fresh weight of tissue, hemes reached the levelsin aerobic controls after 24 h of contact with air, but Pchl(ide)did not. A comparison of the increases during 24-h adaptationto air in levels of heme a and Pchl(ide), which are specificto mitochondria and plastids, respectively, suggested that thedevelopment of mitochondria preceded that of plastids. The rateof synthesis of 5-aminolevulinic acid (ALA) was low in submergedseedlings, as compared to the rate in aerobic controls, butit increased during air adaptation. The sum of the amounts ofheme a, protoheme and Pchl(ide) increased in parallel with theamount of porphyrins, equivalent to the amount of ALA synthesizedduring the experimental period. When submerged seedlings thathad been pretreated with levulinic acid were exposed to air,no Pchl(ide) was formed. In contrast, Pchl(ide) accumulatedunder water when submerged seedlings were fed with ALA. Theseresults indicate that the synthesis of ALA, the limiting stepin the synthesis of Pchl(ide), is repressed under hypoxic conditions.
1 Present address: KRI International, Inc., Kyoto Research Park17, Chudoji Minami-machi, Shimogyo-ku, Kyoto, 600 Japan.
2 Present address: Research Institute for Bioresources, OkayamaUniversity, Kurashiki, 710 Japan. 相似文献