Publications

amino acid sequence of spinach chloroplast fructose-1,6-bisphosphatase.	the amino acid sequence of the spinach chloroplast fructose-1,6-bisphosphatase (fbpase) subunit has been determined. placement of the 358 residues in the polypeptide chain was based on automated edman degradation of the intact protein and of peptides obtained by enzymatic or chemical cleavage. the sequence of spinach chloroplast fbpase shows clear homology (ca. 40%) to gluconeogenic (mammalian, yeast, and escherichia coli) fructose-1,6-bisphosphatases and 80% homology with the wheat chloroplast ...	1990	2159755
regulation of inorganic sulfate activation in filamentous fungi. allosteric inhibition of atp sulfurylase by 3'-phosphoadenosine-5'-phosphosulfate.	atp sulfurylases from penicillium chrysogenum, penicillium duponti, aspergillus nidulans, and neurospora crassa are strongly inhibited by 3'-phosphoadenosine-5'-phosphosulfate (paps), the product of the second (adenosine-5'-phosphosulfate kinase-catalyzed) reaction in the two-step activation of inorganic sulfate. the v versus [paps] plots are sigmoidal. at physiological concentrations of mgatp (0.17-3 mm) and so4(2-) (0.4-10 mm), the [i]0.5 for paps inhibition of the p. chrysogenum enzyme is 35- ...	1990	2162344
sucrose-phosphate synthase is dephosphorylated by protein phosphatase 2a in spinach leaves. evidence from the effects of okadaic acid and microcystin.	sucrose-phosphate synthase (sps) purified from spinach leaves harvested in the dark, was activated by mammalian protein phosphatase 2a (pp2a). activation of sps in a fraction from darkened spinach leaves was largely prevented by either okadaic acid or microcystin-lr (specific inhibitors of ppi and pp2a), while inhibitor-2 (a pp1 inhibitor) or mg2+ (essential for pp2c) were ineffective. in vivo, okadaic acid and microcystin-lr prevented the light-induced activation of sps and decreased sucrose bi ...	1990	2171989
plant and fungus calmodulins are polyubiquitinated at a single site in a ca2(+)-dependent manner.	in plants ca2+ plays a crucial role as second messenger. thus calmodulin is one of the most important signal transducing molecules for metabolic regulation in plants. previously we showed that bovine testis calmodulin can be covalently coupled at one site to ubiquitin in a ca2(+)-dependent manner in the presence of atp/mg2+ by ubiquityl-calmodulin synthetase. since calmodulin from spinach has 13 amino acid sequence differences to bovine calmodulin - two of them in ca2(+)-binding loops - it was u ...	1990	2172031
expression of spinach plastocyanin in e. coli.	an expression vector designed for overexpression of plastocyanin in the periplasmic space of e. coli has been developed. the vector contains the signal peptide sequence of pseudomonas aeruginosa azurin and the mature sequence of spinach plastocyanin. the precursor is efficiently translocated to the periplasmic space and correctly processed to mature plastocyanin. no detectable amount of plastocyanin was present in the cytoplasmic or in the membrane fraction. a large scale preparation of the reco ...	1990	2176166
enhanced translational utilization of chloroplast ribosomal protein mrnas from two aug codons shown by site-directed mutation.	the cdna for protein l12 of the chloroplast ribosome contains two atg codons, both in consensus initiator context, at the beginning of its transit peptide coding region [giese, k., & subramanian, a. r. (1989) biochemistry 28, 3525-3529]. due to the location in the transit peptide, translational start from either atg codon would yield the same mature protein after transport into chloroplasts and n-terminal cleavage. to test whether this arrangement, also found in the cdnas of several other chloro ...	1990	2176872
polypeptide composition of higher plant photosystem i complex. identification of psai, psaj and psak gene products.	high resolution gel electrophoresis of the native photosystem i complex retaining light-harvesting chlorophyll complex revealed the presence of three low-molecular-mass proteins of 7, 4.1 and 3.9 kda in spinach, and 6.8, 4.4 and 4.1 kda in pea, in addition to the other well-characterized higher-molecular-mass components. upon further detergent treatment to deplete light-harvesting chlorophyll complex, the 7 kda and 4.1 kda proteins were removed from the photosystem i core complex of spinach, whi ...	1990	2185953
ethylenethiourea (etu) in relation to use of ethylenebisdithiocarbamate (ebdc) fungicides.	degradation of ethylenebisdithiocarbamate fungicides (ebdcs) is known to produce ethylenethiourea (etu). this article reviews the literature available on the toxicology of ebdcs and etu, the sources in plants and persistence of etu, and its formation during heat treatment of plant products. detoxification techniques developed are mentioned, and maximum residue limits and the results of monitoring studies are given for several countries. some aspects of the methods of analysis are discussed. alth ...	1990	2189164
expression in escherichia coli of the psbo gene encoding the 33 kd protein of the oxygen-evolving complex from spinach.	the cdna for the 33 kd protein from the oxygen-evolving complex of spinach together with the coding region for the hydrophobic c-terminal part of the transit sequence was cloned into the expression plasmid pds12/33ex. the 33 kd protein precursor was expressed in escherichia coli, secreted into the periplasm and correctly processed to the mature 33 kd protein. thus the hydrophobic domain of the transit sequence, preceded by a methionine and two lysine residues, can function as a bacterial signal ...	1990	2189721
purification, characterization, and complete amino acid sequence of a thioredoxin from a green alga, chlamydomonas reinhardtii.	two thioredoxins (named ch1 and ch2 in reference to their elution pattern on an anion-exchange column) have been purified to homogeneity from the green alga, chlamydomonas reinhardtii. in this paper, we described the properties and the sequence of the most abundant form, ch2. its activity in various enzymatic assays has been compared with those of escherichia coli and spinach thioredoxins. c. reinhardtii thioredoxin ch2 can serve as a substrate for e. coli thioredoxin reductase with a lower effi ...	1990	2191628
analysis of the promotors of the single-copy genes for plastocyanin and subunit delta of the chloroplast atp synthase from spinach.	the promotors of the single-copy genes for subunit delta of the chloroplast atp synthase (atpd) and plastocyanin (pc) from spinach have been sequenced, dissected and analysed in transgenic f0 and f1 tobacco plants using the bacterial gus gene as a reporter for promotor activity. the transcription of these genes is photo-controlled. the results have been compared with those obtained for the spinach rbcs-1 gene, one of the light-regulated genes encoding the small subunit of ribulose-1,5-bisphospha ...	1990	2194803
purification and some characteristics of chicken liver l-2-hydroxyacid oxidase a.	the isozyme a of l-2-hydroxyacid oxidase is a peroxisomal flavoenzyme that catalyzes the oxidation of short-chain aliphatic l-2-hydroxyacids in many tissues of higher organisms. a new purification procedure allowed us to obtain a 1400-fold purified enzyme from chicken liver. the n-terminal amino acid of the polypeptide chain was found to be blocked as that of spinach glycolate oxidase, contrastingly with that of rat kidney isozyme b. its amino acid composition was comparable to that of other kno ...	1990	2194838
escherichia coli beta-hydroxydecanoyl thioester dehydrase reacts with native c10 acyl-acyl-carrier proteins of plant and bacterial origin.	beta-hydroxydecanoyl-[acyl-carrier-protein] dehydrase catalyzes the essential step in the formation of unsaturated fatty acids in escherichia coli. this reaction was characterized with native c10 acyl-acyl-carrier protein (acp) structures in both an aqueous phase system and a substrate immobilization assay system. the dehydrase is equally active with e. coli acp, recombinant acp-i derived from spinach, or protein a:acp-i fusion (acyl-thioesters). there were differences among the substrates in te ...	1990	2195995
motional effects on nmr structural data. comparison of spinach and escherichia coli acyl carrier proteins.	proteins in solution need not exist in a single rigid structure but can exist in a dynamic equilibrium among structural forms. the problems that this poses for structure determination using nuclear overhauser effect data from two-dimensional nmr experiments are discussed and illustrated with data on functionally equivalent proteins from two different species. one of these proteins, acyl carrier protein from escherichia coli, shows a single set of resonances, easily interpreted on the basis of a ...	1990	2196884
purification and characterization of cytosolic aldolase from carrot storage root.	a single fructose-1,6-bisphosphate (fbp) aldolase has been detected in extracts from carrot storage roots (daucus carota l.). the enzyme was purified 850-fold to electrophoretic homogeneity and a final specific activity of 26.3 mumols of fbp utilized/min per mg of protein. sds/page of the final preparation revealed a single protein-staining band of 40 kda. the native molecular mass was determined by analytical gel filtration to be 159 kda, indicating that the enzyme is a homotetramer. denaturing ...	1990	2198022
glutathione reductase: comparison of steady-state and rapid reaction primary kinetic isotope effects exhibited by the yeast, spinach, and escherichia coli enzymes.	kinetic parameters for nadph and nadh have been determined at ph 8.1 for spinach, yeast, and e. coli glutathione reductases. nadph exhibited low km values for all enzymes (3-6 microm), while the km values for nadh were 100 times higher (approximately 400 microm). under our experimental conditions, the percentage of maximal velocities with nadh versus those measured with nadph were 18.4, 3.7, and 0.13% for the spinach, yeast, and e. coli enzymes, respectively. primary deuterium kinetic isotope ef ...	1990	2200516
expression in escherichia coli of ferredoxin:nadp+ reductase from spinach. bacterial synthesis of the holoflavoprotein and of an active enzyme form lacking the first 28 amino acid residues of the sequence.	a cdna clone for the preprotein of spinach ferredoxin:nadp+ reductase has been modified to allow the expression in escherichia coli of the mature flavoprotein form the lacks the transit peptide. an expression vector, pfnr1, was constructed by subcloning the fragment into the plasmid pds12/rbsii, sphi. in the crude extracts of transformed cells after induction, two active holoproteins of 35 kda and 32 kda, respectively, were found. the 32-kda protein, purified by immunoaffinity chromatography, wa ...	1990	2202597
the methane monooxygenase gene cluster of methylococcus capsulatus (bath).	methane is oxidised to methanol in methanotrophic bacteria by the enzyme methane monooxygenase (mmo). methylococcus capsulatus (bath) produces a soluble mmo which oxidises a range of aliphatic and aromatic compounds with potential for commercial exploitation. this multicomponent enzyme has been extensively characterised and biochemical data have been used to identify a 12-kb fragment of methylococcus dna carrying the structural genes mmoy and mmoz, coding for the beta- and gamma-subunits of mmo ...	1990	2205538
health in strip cartoons.	strip cartoons are among the most vivid means of communication at our disposal, and they are particularly popular with the young. medical matters have featured in many stories, though usually in a peripheral role. could more be done to use this powerful medium, or would deliberate exploitation destroy it?	1990	2206236
chloroplast glyceraldehyde-3-phosphate dehydrogenase (nadp): amino acid sequence of the subunits from isoenzyme i and structural relationship with isoenzyme ii.	the structural relationship between isoenzymes i and ii of chloroplast glyceraldehyde-3-phosphate dehydrogenase (d-glyceraldehyde-3-phosphate: nadp+ oxidoreductase (phosphorylating) ec 1.2.1.13) has been established at the protein level. the complete primary structure of subunits a and b of glyceraldehyde-3-phosphate dehydrogenase i from spinacia oleracea has been determined by sequence analysis of the corresponding tryptic peptides, aligned by fragments derived from cyanogen bromide and staphyl ...	1990	2223845
restriction site and genetic map of cucurbita pepo chloroplast dna.	a detailed restriction map of squash chloroplast dna (cpdna) was constructed with five restriction endonucleases, sali, pvuii, bgli, sacii, and psti. the cleavage sites were mapped by sequential digestion of cpdna using low-gelling temperature agarose. the restriction map shows that squash cpdna is an approximately 153 kilobase (kb) circle with a large inverted repeat sequence of 23.3 kb, separated by a large (83.7 kb) and a small (22.7 kb) single copy region. genes for a number of chloroplast p ...	1990	2249258
structural and geometrical isomers of carotenoids in human plasma.	we have quantitatively analyzed human plasma for the following carotenoids: all-trans-lutein, all-trans-zeaxanthin, alpha-cryptoxanthin, beta-cryptoxanthin, the sum of all-trans-lycopene and its cis isomers, alpha-carotene and beta-carotene. in addition, we have tentatively identified and quantified 13-cis-lutein and 13-cis-zeaxanthin in human plasma. the latter two cis isomers are also apparent in samples of two common food items, spinach and corn meal. we have analyzed the ratios of all of the ...	1990	2262811
ribosomal protein l35: identification in spinach chloroplasts and isolation of a cdna clone encoding its cytoplasmic precursor.	we describe the isolation of spinach chloroplast ribosomal protein l35 and characterization of a cdna clone encoding its cytoplasmic precursor. this protein was only recently identified in ribosomes, but the sequences of four l35 genes have now been reported and confirm its presence in eubacteria, chloroplasts, and cyanelles. using n-terminal sequence data, oligonucleotides were designed and a cdna library was screened. the nucleotide sequence of the cdna clones shows that the spinach l35 protei ...	1990	2271612
mandelate pathway of pseudomonas putida: sequence relationships involving mandelate racemase, (s)-mandelate dehydrogenase, and benzoylformate decarboxylase and expression of benzoylformate decarboxylase in escherichia coli.	the genes that encode the five known enzymes of the mandelate pathway of pseudomonas putida (atcc 12633), mandelate racemase (mdla), (s)-mandelate dehydrogenase (mdlb), benzoylformate decarboxylase (mdlc), nad(+)-dependent benzaldehyde dehydrogenase (mdld), and nadp(+)-dependent benzaldehyde dehydrogenase (mdle), have been cloned. the genes for (s)-mandelate dehydrogenase and benzoylformate decarboxylase have been sequenced; these genes and that for mandelate racemase [ransom, s. c., gerlt, j. a ...	1990	2271624
partial reduction in ribulose 1,5-bisphosphate carboxylase/oxygenase activity by carboxypeptidase a.	treatment with carboxypeptidase a of ribulose bisphosphate carboxylase/oxygenase (rubisco) from spinach and chlamydomonas, but not tobacco, reduced activity by 60-70%. further studies with the spinach enzyme indicated that only one amino acid from each of the large (valine) and small (tyrosine) subunits was removed and the loss of activity was correlated with modification of the large subunit. the modified enzyme also had a two-fold greater km for rubp but co2/o2 specificity was only 5% lower an ...	1990	2275551
vitamin a potency of carrot and spinach carotenes in human metabolic studies.	changes in plasma retinol and carotenoids was measured in 17 young males after daily ingestion of grated carrots, carrot juice or spinach leaves for 2 weeks. regression equations showed that the supply of 3350 and 4750 micrograms carotenes from 78 ml carrot juice (prepared from 185 g carrots) or 91 g grated carrots, respectively were adequate in maintaining plasma retinol at a constant level in subjects with initial plasma retinol of 1.2 mumol/l. under similar experimental conditions, 280 g boil ...	1990	2276879
calculation of subunit stoichiometry of large, multisubunit proteins from amino acid compositions.	the subunit stoichiometry of a large, multisubunit protein can be determined from the molar amino acid compositions (i amino acids) of the protein and its subunits. the number of copies of the subunits (1, 2, ... j) is calculated by solving all possible combinations of simultaneous equations in j unknowns (i!/j!(i - j)!). calculations carried out using the published amino acid compositions determined by analysis and the compositions calculated from the sequences for two proteins of known stoichi ...	1990	2321761
l-lactate 2-monooxygenase from mycobacterium smegmatis. cloning, nucleotide sequence, and primary structure homology within an enzyme family.	l-lactate 2-monooxygenase catalyzes the oxidation of l-lactate to acetate and carbon dioxide. the catalytic mechanism has been extensively investigated but very little is known about which amino acid residues may play a role in catalysis. as a first step toward this goal, the gene for this protein from mycobacterium smegmatis has been cloned and sequenced. peptide sequencing data for l-lactate 2-monooxygenase was used to construct three sets of fully redundant tetradecamer oligonucleotide probes ...	1990	2324094
modulation of spinach chloroplast nadp-glyceraldehyde-3-phosphate dehydrogenase by chaotropic anions.	neutral salts enhanced the specific activity of chloroplast nadp-glyceraldehyde-3-phosphate dehydrogenase (d-glyceraldehyde-3-phosphate:nadp+ oxidoreductase (phosphorylating), ec 1.2.1.13) from spinach leaves. the ordering of the respective anions, according to the concentration for maximal stimulation, yielded the lyotropic (hofmeister) series [scn- (0.05 m), clo-4 (0.08 m), cl3cco-2 (0.24 m), i- (0.35 m), br- (0.6 m), cl- (1.0 m)]; the more chaotropic the anion the less its concentration for m ...	1990	2337356
purification and characterization of nadph-ferredoxin reductase from bovine kidney mitochondria.	an nadph-ferredoxin reductase (ec 1.6.7.1) was purified from bovine kidney mitochondria and its physicochemical properties were investigated. the ratio of the absorbances at 272 and 450 nm was 8.8, and the enzyme had a specific activity of 5,850 nmol/min/mg for the reduction of cytochrome c. we determined the molecular weights of the nadph-ferredoxin reductase as 53,000 and 34,000 da by sds-page and hplc analysis, respectively. renal ferredoxin was substituted by adreno-ferredoxin, but spinach f ...	1990	2355662
contrasting evolutionary histories of chloroplast thioredoxins f and m.	fourteen thioredoxin sequences were used to construct a minimal phylogenetic tree by using parsimony. the bacterial thioredoxins clustered into three groups: one containing the photosynthetic purple bacteria, escherichia and corynebacterium; a second containing the photosynthetic green bacterium, chlorobium; and a third containing cyanobacteria. these groupings are similar to those generated from earlier 16s rna analyses. animal thioredoxins formed a fourth group. the two thioredoxins of chlorop ...	1990	2359363
skin and liver toxicity in experimental lantana camara poisoning in albino rats.	dried alcoholic extract of fresh lantana camara leaves (le), on oral administration to albino rats of both sexes, induced photodermatitis during exposure to clear sunlight for 1 hr. its severity was related to the dose of le and was maximal in rats exposed to sunlight from 4 to 14 hr after feeding le and gradually declined over 40 hr. wavelengths of light about 540 to 570 mu only were effective. in control study, the alcoholic extract of edible spinach leaves was only 1/3 in potency and its effe ...	1990	2361717
nucleotide sequence of the maize chloroplast rpo b/c1/c2 operon: comparison between the derived protein primary structures from various organisms with respect to functional domains.	the genes (rpo b/c1/c2) coding for the beta, beta', beta" subunits of maize (zea mays) chloroplast rna polymerase have been located on the plastome and their nucleotide sequences established. the operon is part of a large inversion with respect to the tobacco and spinach chloroplast genomes and is flanked by the genes trnc and rps2. notable features of the nucleotide sequence are the loss of an intron in rpoc1 and an insertion of approximately 450 bp in rpoc2 compared to the dicotyledons tobacco ...	1990	2381419
rice chloroplast rna polymerase genes: the absence of an intron in rpoc1 and the presence of an extra sequence in rpoc2.	the chloroplast genome contains sequences homologous to the escherichia coli rpoa, rpob and rpoc genes. the chloroplast rpoc gene is divided into rpoc1 and rpoc2, of which rpoc1 contains an intron. comparison of the rice rpo genes with those from tobacco, spinach and liverwort revealed unique features of the rice genes; the lack of an intron in rpoc1 and the presence of an extra sequence of 381 bp in rpoc2. the intron in rpoc1 is thus optional, and possible intron boundary sites in split rpoc1 g ...	1990	2381420
a ribosomal protein is encoded in the chloroplast dna in a lower plant but in the nucleus in angiosperms. isolation of the spinach l21 protein and cdna clone with transit and an unusual repeat sequence.	the distribution of chloroplast ribosomal protein genes between the organelle dna and the nuclear dna is highly conserved in land plants, but a notable exception is rpl21. this gene has been found in the completely sequenced chloroplast genome of a lower plant but not in that of two higher plants. we describe the purification and characterization of the spinach chloroplast ribosomal protein l21 and the isolation and nucleotide sequence of a cdna clone that encodes its cytoplasmic precursor. the ...	1990	2398071
concentrations of lead and cadmium in edible vegetables from tarragona province, spain.	the lead and cadmium content of 20 species of edible vegetable collected in tarragona province (spain) was investigated. samples consisting of bulbs, and leaves and soft stalks (chard, parsley, spinach and lettuce) contained the highest levels of both metals. in contrast, fruits and similar garden produce (tomato, green pepper, cucumber, artichoke, green bean and broad bean) contained the lowest concentrations of lead and cadmium in both the northern and southern area of the province. most speci ...	1990	2402626
[nucleic acid components in carbohydrate-rich food].	the content of nucleic acid components in numerous foods, especially carbohydrate-rich ones, has been investigated. the data obtained for bases (purines and pyrimidines) were calculated as nucleic-acid equivalents (rna or dna); the imp content was calculated from the measured content of hypoxanthine. not only did cultivated plants such as cereals and pulses show a high rna-equivalent content but also vegetables such as spinach, leek, broccoli, chinese cabbage and cauliflower. we found the same r ...	1990	1689090
organochlorine pesticide residues in different indian cereals, pulses, spices, vegetables, fruits, milk, butter, deshi ghee, and edible oils.	a total of 244 samples of cereals (wheat flour, rice, and maize), pulses (arhar, moong, gram, lentil, and black gram), spices (turmeric, chili, coriander, and black pepper), vegetables (potato, onion, spinach, cabbage, brinjal, and tomato), fruits (mango, guava, apple, and grape), milk, butter, deshi ghee, and edible oils (vegetable, mustard, groundnut, and sesame) collected from different cities of northern province (utter pradesh) were analyzed by gas liquid chromatography for the presence of ...	1990	1698760
determination of oxygen emission and uptake in leaves by pulsed, time resolved photoacoustics.	pulsed, time resolved photoacoustics has sufficient sensitivity to determine oxygen emission and uptake by single turnover flashes to leaves. the advantage over previous methodologies is that when combined with single turnover flashes the kinetics of the thermal and the gas signals can be resolved to 0.1 millisecond and separated. the s-state oscillations of oxygen formation are readily observed. the gas signal from common spongy leaves such as spinach (spinacia sp.), japanese andromeda (pieris ...	1990	16667697
nitrite photoreduction in vivo is inhibited by oxygen.	it was hypothesized previously that an o(2) inhibition of no(2) (-) photoreduction would reflect a competition between o(2) and no(2) (-) for electrons from ferredoxin at the site of plastid nitrite reductase. in order to test this in vivo, intact spinach (spinacia oleracea l.) leaf chloroplast and mesophyll cell isolates held in high light were aerated with streams of 20% o(2)/80% n(2) (250 micromolar o(2) in aqueous solution) or, alternatively, streams of 100% n(2). bicarbonate plus co(2) and ...	1990	16667362
d-glucosone and l-sorbosone, putative intermediates of l-ascorbic acid biosynthesis in detached bean and spinach leaves.	d-[6-(14)c]glucosone that had been prepared enzymically from d-[6-(14)c]glucose was used to compare relative efficiencies of these two sugars for l-ascorbic acid (aa) biosynthesis in detached bean (phaseolus vulgaris l., cv california small white) apices and 4-week-old spinach (spinacia oleracea l., cv giant noble) leaves. at tracer concentration, (14)c from glucosone was utilized by spinach leaves for aa biosynthesis much more effectively than glucose. carbon-14 from [6-(14)c]glucose underwent ...	1990	16667861
conversion of l-sorbosone to l-ascorbic acid by a nadp-dependent dehydrogenase in bean and spinach leaf.	an nadp-dependent dehydrogenase catalyzing the conversion of l-sorbosone to l-ascorbic acid has been isolated from phaseolus vulgaris l. and spinacia oleracea l. and partially purified. it is stable at -20 degrees c for up to 8 months. molecular masses, as determined by gel filtration, were 21 and 29 kilodaltons for bean and spinach enzymes, respectively. k(m) for sorbosone were 12 +/- 2 and 18 +/- 2 millimolar and for nadp(+), 0.14 +/- 0.05 and 1.2 +/- 0.5 millimolar, for bean and spinach, resp ...	1990	16667860
polysaccharide fraction from higher plants which strongly interacts with the cytosolic phosphorylase isozyme : i. isolation and characterization.	from leaves of spinacia oleracea l. or from pisum sativum l. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. the apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. glucose, galactose, arabinose, and ribose were the main monosaccharide compou ...	1990	16667877
biosynthesis of digalactosyldiacylglycerol in plastids from 16:3 and 18:3 plants.	intact chloroplasts isolated from leaves of eight species of 16:3 and 18:3 plants and chromoplasts isolated from narcissus pseudonarcissus l. flowers synthesize galactose-labeled mono-, di-, and trigalactosyldiacylglycerol (mgdg, dgdg, and tgdg) when incubated with udp-[6-(3)h]galactose. in all plastids, galactolipid synthesis, and especially synthesis of dgdg and tgdg, is reduced by treatment of the organelles with the nonpenetrating protease thermolysin. envelope membranes isolated from thermo ...	1990	16667615
characterization and compartmentation, in green leaves, of hexokinases with different specificities for glucose, fructose, and mannose and for nucleoside triphosphates.	when green leaves of spinach (spinacia oleracea l.) were surveyed for the presence of hexokinases which utilize glucose, fructose and-or mannose as a substrate, four kinases could be distinguished by their order of elution during chromatography on diethylaminoethyl (deae)-cellulose: (i) a hexokinase i with a specificity for fructose, glucose, and mannose, (ii) a fructokinase i with a specificity for fructose, (iii) a hexokinase ii with a specificity for glucose, fructose and mannose, and (iv) a ...	1990	24196745
sulfhydryl reagents and energy-linked reactions in monocot thylakoids.	monofunctional maleimides have been used to covalently modify the coupling factor protein of monocot thylakoid membranes. as with dicot thylakoids, incubation of the monocot thylakoids with maleimides in the light but not in the dark results in inhibition of both atp synthesis and hydrolysis. in the dark, sites on the gamma and epsilon subunits of maize zea mays coupling factor 1 are modified after incubation of maize mesophyll thylakoids with the fluorescent maleimide n-(anilinonaphthyl-4) male ...	1990	16667548
cause for dark, chilling-induced inactivation of photosynthetic oxygen-evolving system in cucumber leaves.	effects on oxygen evolution of the storage of detached cucumber (cucumis sativus) leaves at 0 degrees c in the dark were investigated with thylakoids and oxygen-evolving photosystem ii membranes isolated from stored leaves. the cold and dark treatment of leaves selectively inactivated electron transport on the oxidizing side of photosystem ii. photosystem ii membranes isolated from treated leaves were largely depleted of two proteins of 20 and 14 kilodaltons, which correspond to the extrinsic 23 ...	1990	16667624
thermal dependence of the apparent k(m) of glutathione reductases from three plant species.	the thermal dependencies of the apparent k(m) of the glutathione reductases from spinach (spinacia oleracea l.) corn (zea mays l.), and cucumber (cucumis sativus l.) were determined. the apparent k(m) of the enzymes were found to vary up to 9-fold between 12.5 and 45 degrees c. values of the apparent k(m) in excess of 200% of the observed minimum are suggested to be detrimental to the normal function of the enzyme. we propose the term "thermal kinetic window" to describe to the range of temperat ...	1990	16667543
[atropine poisoning by mandragora autumnalis. a report of 15 cases].	anticholinergic syndrome (as) due to accidental poisoning is exceptional. mandragora contains a high concentration of atropine, hiosciamine and scopolamine. we have evaluated 15 patients with as due to poisoning by mandragora autumnalis, distributed in two family groups. the latency period since the ingestion was 1-4 hours (means = 2.7 +/- 0.9). the clinical features corresponded to an as of variable severity. all patients had blurred vision and dryness of mouth, nine (60%) had difficult micturi ...	1990	2087109
proteins from frost-hardy leaves protect thylakoids against mechanical freeze-thaw damage in vitro.	we have isolated protein fractions from cold-acclimated, frost-hardy cabbage (brassica oleracea l.) and spinach (spinacia oleracea l.) leaves which protect isolated thylakoids from non-hardy spinach against mechanical membrane rupture during an in-vitro freeze-thaw cycle. no protective activity was found in similar preparations from non-hardy leaves. the proteins protected the membranes from damage by reducing their solute permeability during freezing and by increasing their expandability during ...	1990	24202022
effect of growth temperature and temperature shifts on spinach leaf morphology and photosynthesis.	the growth kinetics of spinach plants (spinacia oleracea l. cv savoy) grown at 5 degrees c or 16 degrees c were determined to allow us to compare leaf tissues of the same developmental stage rather than chronological age. the second leaf pairs reached full expansion at a plant age of 32 and 92 days for the 16 degrees c and 5 degrees c plants, respectively. growth at 5 degrees c resulted in an increased leaf area, dry weight, dry weight per area, and leaf thickness. despite these changes, pigment ...	1990	16667923
desaturation of oleoyl groups in envelope membranes from spinach chloroplasts.	envelope membranes isolated from chloroplasts of spinach (spinacia oleracea) desaturate oleoyl groups in monogalactosyl diacylglycerol to linoleoyl groups. the desaturation requires nadph in combination with ferredoxin and is not restricted to monogalactosyl diacylglycerol, since it is also observed in biosynthetic intermediates as, for example, in phosphatidic acid. this indicates a certain degree of unspecificity of the oleate desaturase in isolated envelope membranes. lipid desaturation is an ...	1990	11607123
novel forms of ferredoxin and ferredoxin-nadp reductase from spinach roots.	ferredoxin and the enzyme catalyzing its reduction by nadph, ferredoxin-nadp reductase (ferredoxin-nadp+ oxidoreductase or fnr), were found to be present in roots of spinach (spinacia oleracea). localization experiments with endosperm of germinating castor beans (ricinus communis), a classical nonphotosynthetic tissue for cell fractionation studies, confirmed that ferredoxin and fnr are localized in the plastid fraction. both proteins were purified from spinach roots and found to resemble their ...	1990	2241175
localization of atp sulfurylase and o-acetylserine(thiol)lyase in spinach leaves.	the intracellular compartmentation of atp sulfurylase and o-acetylserine(thiol)lyase in spinach (spinacia oleracea l.) leaves has been investigated by isolation of organelles and fractionation of protoplasts. atp sulfurylase is located predominantly in the chloroplasts, but is also present in the cytosol. no evidence was found for atp sulfurylase activity in the mitochondria. two forms of atp sulfurylase were separated by anion-exchange chromatography. the more abundant form is present in the ch ...	1990	16667839
activation of sucrose-phosphate synthase from darkened spinach leaves by an endogenous protein phosphatase.	sucrose-phosphate synthase (sps; ec 2.4.1.14) extracted from darkened spinach (spinacia oleracea l.) leaves has a low activation state, defined as the ratio of activity measured with limiting substrates (plus the inhibitor pi) to activity with saturating substrates (maximum velocity). preincubation at 25 degrees c of desalted crude extracts from darkened leaves resulted in a time-dependent increase in activation state that was inhibited by pi [ic50 (concentration causing 50% inhibition) approxim ...	1990	2173486
free fatty acids regulate two galactosyltransferases in chloroplast envelope membranes isolated from spinach leaves.	effects of mgcl(2) and free fatty acids (ffa) on galactolipid:galactolipid galactosyltransferase (gggt) and udp-galactose: 1,2-diacylglycerol galactosyltransferase (udgt) in chloroplast envelope membranes isolated from spinach (spinacia oleracea l.) leaves were examined. gggt activity was sigmoidally stimulated by mgcl(2) with a saturated concentration of more than 5 millimolar. free alpha-linolenic acid (18:3) caused a drastic increase in gggt activity under limiting concentrations of mgcl(2), ...	1990	16667779
pathway for the synthesis of triacylglycerols from monogalactosyldiacylglycerols in ozone-fumigated spinach leaves.	when the upper leaf surface of spinach (spinacia oleracea l.) plants was treated with [1-(14)c]acetate and grown for 2 days, (14)c was effectively incorporated into acyl moieties of leaf lipids in ratios approximately their composition by mass. fumigation of the plants with ozone (0.5 microliter per liter) caused a redistribution of (14)c among lipid classes, i.e. a marked increase of (14)c content in triacylglycerol (tg) and 1,2-diacylglycerol (1,2-dg) and a decrease of label in monogalactosyld ...	1990	16667778
conversion of monogalactosyldiacylglycerols to triacylglycerols in ozone-fumigated spinach leaves.	molecular species and fatty acid distribution of triacylglycerol (tg) accumulated in spinach (spinacia oleracea l.) leaves fumigated with ozone (0.5 microliter per liter) were compared with those of monogalactosyldiacylglycerol (mgdg). analysis of positional distribution of the fatty acids in mgdg and the accumulated tg by the enzymatic digestion method showed that hexadecatrienoate (16:3) was restricted to sn-2 position of the glycerol backbone in both mgdg and tg, whereas alpha-linolenate (18: ...	1990	16667777
freezing of isolated thylakoid membranes in complex media. vi. the effect of ph.	thylakoid membranes isolated from spinach leaves (spinacia oleracea l. cv. monatol) were used as a model biomembrane system for evaluating the significance of the hydrogen ion activity for cryoprotection. after freeze-thaw treatment in a buffered complex medium adjusted to various ph, light-induced photosynthetic membrane reactions were determined at optimum proton concentration. when thylakoids were suspended at hydrogen ion activities above and below the physiologically important ph range, irr ...	1990	2249457
regulation of photosynthetic sucrose synthesis: a role for calcium?	we have investigated whether changes of the cytosolic free-calcium concentration could regulate photosynthetic sucrose synthesis. partially purified enzymes from spinach (spinacea oleracea l.) leaves were assayed using calcium-egta buffers to obtain defined free-calcium concentrations in the low micromolar and submicromolar ranges. these concentrations of calcium did not directly affect sucrose-phosphate synthase activity. they inhibited the cytosolic fructose-1,6-bisphosphatase, acting competit ...	1990	24197102
involvement of ferredoxin in desaturation of lipid-bound oleate in chloroplasts.	intact spinach (spinacia oleracea) chloroplasts, pulse-labeled with [(14)c]acetate, desaturate newly formed fatty acids as ester groups of monogalactosyl diacylglycerol in a subsequent chase in the dark. rupture of pulse-labeled chloroplasts by addition of a detergent solution 3-([3-cholamidopropyl]dimethylammonio)-1-propane sulfonate preserves part of this desaturation activity. direct addition of different free fatty acids together with appropriate cofactors to detergent-ruptured chloroplasts ...	1990	16667689
photoinhibition at chilling temperatures and effects of freezing stress on cold acclimated spinach leaves in the field. a fluorescence study.	the role of high light stress in a natural environment was studied on spinach plants (spinacia oleracea l. cv. wolter) grown in the field during the winter season. fluorescence induction (at 293 k and 77 k) of leaves was used to characterize the stress effects. night frost with minimum temperatures between - 1.5°c and -7.5°c (i.e. above the'frost killing point'at ca. -11.5°c) led to impaired photosynthesis. this was seen as increased initial fluorescence (f(o) ), decreased ratio of variable to m ...	1990	21087269
activity of ribulose 1,5-bisphosphate carboxylase oxygenase as a function of storage conditions.	optimal storage conditions to retain ribulose 1, 5-bisphosphate carboxylase/oxygenase (rubisco) activity were investigated. the soluble spinach (spinacia oleracea) enzyme was pretreated with its activators, mg(2+) and hco(3) (-), and then stored for up to 30 days at 4 or -18 degrees c or in liquid n(2). cold inactivation and conformational changes were suggested to be involved during rubisco storage in the cold, leading to its inactivation. pretreatment of the enzyme with mg(2+) and co(2) and su ...	1990	16667648
light saturation response of inactive photosystem ii reaction centers in spinach.	the effective absorption cross section of inactive photosystem ii (ps ii) centers, which is the product of the effective antenna size and the quantum yield for photochemistry, was investigated by comparing the light saturation curves of inactive ps ii and active reaction centers in intact chloroplasts and thylakoid membranes of spinach (spinacia oleracea). inactive ps ii centers are defined as the impaired ps ii reaction centers that require greater than 50 ms for the reoxidation of qa (-) subse ...	1990	24420169
control of photosynthate partitioning in spinach leaves : analysis of the interaction between feedforward and feedback regulation of sucrose synthesis.	experiments were carried out to estimate the elasticity coefficients and thence the distribution of control of sucrose synthesis and photosynthate partitioning between cytosolic fructose-1,6-bisphosphatase and sucrose-phosphate synthase (sps), by applying the dualmodulation method of kacser and burns (1979, biochem. soc. trans. 7, 1149-1161). leaf discs of spinach (spinacia oleracea l.) were harvested at the beginning and end of the photoperiod and illuminated at five different irradiances to al ...	1990	24196941
carbon metabolism in spinach leaves as affected by leaf age and phosphorus and sulfur nutrition.	spinach (spinacea oleracea) plants were grown either continuously on complete nutrient solutions or for 2 weeks on media deficient in phosphate or sulfate. to characterize leaf carbohydrate metabolism, levels of phosphorylated intermediates, activities of enzymes involved in photosynthetic carbon metabolism, contents of soluble and acid hydrolyzable sugars were measured in leaves differing in age and mineral status and related to leaf rates of photosynthesis and assimilate partitioning. concentr ...	1990	16667581
the aggregation states of spinach phosphoribulokinase.	phosphoribulokinase (prk; ec 2.1.7.19) is active in illuminated chloroplasts and inactive in darkened chloroplasts. this regulatory mechanism is mediated by thioredoxin-dependent reduction of a kinase disulfide in vivo. extracts of spinach (spinacia oleracea l.) leaves in the presence of 10 mm dithiothreitol contain a single 80-kda form of prk as judged by gel filtration. gel filtration of thiol-free extracts of light-harvested tissue shows the presence of two inactive forms of prk, the 80-kda f ...	1990	24196813
shikimate kinase from spinach chloroplasts : purification, characterization, and regulatory function in aromatic amino acid biosynthesis.	shikimate kinase was purified to near homogenity from spinach spinacia oleracea l. chloroplasts and found to consist of a single 31 kilodalton polypeptide. the purified enzyme was unstable, but could be stabilized by a variety of added proteins, including oxidized and reduced thioredoxins. whereas the isolated enzyme was stimulated by mono- and dithiol reagents, the enzyme in intact chloroplasts was unaffected by added thiols and showed only minor response to dark/light transitions. these result ...	1990	16667533
isolation and characterization of the cytosolic and chloroplastic 3-phosphoglycerate kinase from spinach leaves.	the cytosol and chloroplast 3-phosphoglycerate kinases (3-pgk) from spinach (spinacia oleracea l.) were purifled to apparent homogeneity. the procedure included a conventional anion-exchange chromatography on deae-cellulose and mainly a series of hplc columns. the charge differences of the two isoenzymes were so small that separation was only successful by anion-exchange chromatography on a hplc synchropak ax 300 column. the portion of the two isoenzmyes in leaf tissue was estimated as 5% and 95 ...	1990	16667463
status of the substrate binding sites of ribulose bisphosphate carboxylase as determined with 2-c-carboxyarabinitol 1,5-bisphosphate.	the properties of the tight and specific binding of 2-c-carboxy-d-arabinitol 1,5-bisphosphate (cabp), which occurs only to reaction sites of ribulose 1,5-bisphosphate carboxylase (rubisco) that are activated by co(2) and mg(2+), were studied. with fully active purified spinach (spinacia oleracea) rubisco the rate of tight binding of [(14)c]cabp fit a multiple exponential rate equation with half of the sites binding with a rate constant of 40 per minute and the second half of the sites binding at ...	1990	16667442
chlamydomonas reinhardtii phosphoribulokinase : sequence, purification, and kinetics.	the sequence and kinetic properties of phosphoribulokinase purified from chlamydomonas reinhardtii were determined and compared with the spinach (spinacea oleracea) enzyme. chlamydomonas phosphoribulokinase was purified to apparent homogeneity, with a specific activity of 410 micromoles per minute per milligram. polyclonal antibodies to the purified protein were used to isolate a chlamydomonas cdna clone, which, upon sequencing, was found to contain the entire coding region. the transit peptide ...	1990	16667433
regulation of sedoheptulose-1,7-bisphosphatase by sedoheptulose-7-phosphate and glycerate, and of fructose-1,6-bisphosphatase by glycerate in spinach chloroplasts.	using partially purified sedoheptulose-1,7-bisphosphatase from spinach (spinacia oleracea l.) chloroplasts the effects of metabolites on the dithiothreitoland mg(2+)-activated enzyme were investigated. a screening of most of the intermediates of the calvin cycle and the photorespiratory pathway showed that physiological concentrations of sedoheptulose-7-phosphate and glycerate specifically inhibited the enzyme by decreasing its maximal velocity. an inhibition by ribulose-1,5-bisphosphate was als ...	1990	24196680
molecular cloning of a plant betaine-aldehyde dehydrogenase, an enzyme implicated in adaptation to salinity and drought.	many plants, as well as other organisms, accumulate betaine (n,n,n-trimethylglycine) as a nontoxic or protective osmolyte under saline or dry conditions. in plants, the last step in betaine synthesis is catalyzed by betaine-aldehyde dehydrogenase (badh, ec 1.2.1.8), a nuclear-encoded chloroplastic enzyme. a cdna clone for badh (1812 base pairs) was selected from a lambda gt10 cdna library derived from leaves of salt-stressed spinach (spinacia oleracea l.). the library was screened with oligonucl ...	1990	2320587
sensitivity of photosynthesis by spinach chloroplast membranes to osmotic stress in vitro: rapid inhibition of o2 evolution in presence of magnesium.	thylakoids prepared from spinach (spinacea oleracea l.) chloroplasts were exposed to osmotic stress in vitro in the presence or absence of different inorganic salts. by an hour after incubation in 1.0 m sorbitol and 10 mm (or more) mgcl2, the thylakoids lost approximately 80% of their photosystem (ps) ii activity, but not ps i. the inhibition occurred only in presence of magnesium as indicated by the combinations of several cations/anions. the ps ii activity was relatively insensitive to osmotic ...	1990	24419656
oxidation versus reductive detoxification of so(2) by chloroplasts.	intact chloroplasts isolated from spinach (spinacia oleracea l. cv yates) both oxidized and reduced added sulfite in the light. oxidation was fast only when endogenous superoxide dismutase was inhibited by cyanide. it was largely suppressed by scavengers of oxygen radicals. after addition of o-acetylserine, chloroplasts reduced sulfite to cysteine and exhibited sulfite-dependent oxygen evolution. cysteine synthesis from sulfite was faster than from sulfate. the results are discussed in relation ...	1990	16667358
on the regulation of spinach nitrate reductase.	a coupled assay has been worked out to study spinach (spinacea oleracea l.) nitrate reductase under low, more physiological concentrations of nadh. in this assay the reduction of nitrate is coupled to the oxidation of malate catalyzed by spinach nad-malate dehydrogenase. the use of this coupled system allows the assay of nitrate reductase activity at steady-state concentrations of nadh below micromolar. we have used this coupled assay to study the kinetic parameters of spinach nitrate reductase ...	1990	16667335
subcellular compartmentation of uridine nucleotides and nucleoside-5' -diphosphate kinase in leaves.	the subcellular compartmentation of nucleoside diphosphate kinase (ec 2.7.4.6) and the uridine nucleotides has been studied in leaves. membrane filtration of barley (hordeum vulgare l.) leaf mesophyll protoplasts and differential centrifugation of spinach (spinacia oleracea l.) leaf extracts showed that about half the nucleoside diphosphate kinase is present in the cytosol. the activity is adequate to account for the turnover of utp and udp during photosynthetic sucrose synthesis. nonaqueous den ...	1990	16667327
protective systems against active oxygen species in spinach: response to cold acclimation in excess light.	spinach (spinacia oleracea l.) plants were acclimated to 1° c or maintained at 18° c under the same light regime (260-300 μmol photons·m(-2)·s(-1)). the cold acclimation led to several metabolic and biochemical changes that apparently include improved protection of the photosynthetic apparatus against active oxygen species. in particular, cold-acclimated leaves exhibited a considerably higher ascorbate content and significantly increased activities of superoxide dismutase, ascorbate peroxidase, ...	1990	24202017
the ferredoxin-thioredoxin system of a green alga, chlamydomonas reinhardtii : identification and characterization of thioredoxins and ferredoxin-thioredoxin reductase components.	the components of the ferredoxin-thioredoxin (ft) system of chlamydomonas reinhardtii have been purified and characterized. the system resembled that of higher plants in consisting of a ferredoxin-thioredoxin reductase (ftr) and two types of thioredoxin, a single f and two m species, m1 and m2. the chlamydomonas m and f thioredoxins were antigenically similar to their higher-plant counterparts, but not to one another. the m thioredoxins were recognized by antibodies to both higher-plant m and ba ...	1990	24202012
freezing of isolated thylakoid membranes in complex media. v. inactivation and protection of electron transport reactions.	when chloroplast thylakoid membranes isolated from spinach leaves (spinacia oleracea l. cv. monatol) were frozen in media containing the predominant inorganic electrolytes of the chloroplast stroma, linear photosynthetic electron transport became progressively inhibited. after onset of freezing, both psii- and psi-mediated electron flow were inactivated almost to the same extent. prolonged storage of the membranes in the frozen state increased damage to psii relative to psi activity. under these ...	1990	24420991
reversible photoinhibition of unhardened and cold-acclimated spinach leaves at chilling temperatures.	the photoinhibition of photosynthesis at chilling temperatures was investigated in cold-acclimated and unhardened (acclimated to +18° c) spinach (spinacia oleracea l.) leaves. in unhardened leaves, reversible photoinhibition caused by exposure to moderate light at +4° c was based on reduced activity of photosystem (ps) ii. this is shown by determination of quantum yield and capacity of electron transport in thylakoids isolated subsequent to photoinhibition and recovery treatments. the activity o ...	1990	24201942
spinach chloroplastic carbonic anhydrase: nucleotide sequence analysis of cdna.	we have determined the nucleotide sequence of a cdna encoding spinach (spinacia oleracea) chloroplastic carbonic anhydrase (ca). the open reading frame encodes a protein consisting of a transit peptide and a mature ca protein with a predicted mass of 24, 116 daltons. this represents the first report of a nucleotide sequence of a plant ca.	1990	16667262
a novel role for light in the activation of ribulosebisphosphate carboxylase/oxygenase.	light stimulated the activation of ribulosebisphosphate carboxylase/oxygenase (rubisco) in a buffered lysed chloroplast system in the presence of saturating concentrations of atp. this indicates a role for light in the rubisco activase activation system in addition to the previously identified requirement for the synthesis of atp. rubisco activation was nearly as great at low irradiance (10 micromoles of photons per square meter per second) as at high irradiance (1000 micromoles of photons per s ...	1990	16667230
the ferredoxin-thioredoxin system of a green alga, chlamydomonas reinhardtii: identification and characterization of thioredoxins and ferredoxin-thioredoxin reductase components.	the components of the ferredoxin-thioredoxin (ft) system of chlamydomonas reinhardtii have been purified and characterized. the system resembled that of higher plants in consisting of a ferredoxin-thioredoxin reductase (ftr) and two types of thioredoxin, a single f and two m species, m1 and m2. the chlamydomonas m and f thioredoxins were antigenically similar to their higher-plant counterparts, but not to one another. the m thioredoxins were recognized by antibodies to both higher plant m and ba ...	1990	11538175
ribulose-1,5-bisphosphate carboxylase-oxygenase, other calvin-cycle enzymes, and chlorophyll decrease when glucose is supplied to mature spinach leaves via the transpiration stream.	the inhibition of photosynthesis after supplying glucose to detached leaves of spinach (spinacia oleracea l.) was used as a model system to search for mechanisms which potentially contribute to the "sink" regulation of photosynthesis. detached leaves were supplied with 50 mm glucose or water for 7 d through the transpiration stream, holding the leaves in low irradiance (16 μmol photons · m(-2) · s(-1)) and a cycle of 9 h light/15 h darkness to prevent any endogenous accumulation of carbohydrate. ...	1991	24186575
adpg formation by the adp-specific cleavage of sucrose-reassessment of sucrose synthase.	the standardized enzyme coupling method for assaying sucrose synthase activities in the direction of sucrose cleavage was reexamined using enzyme preparations from cultured cells of sycamore (acer pseudoplatanus l.) and spinach leaves (spinacea oleracea). both atp and tris, commonly utilized in assay systems to measure sucrose synthase, were found to inhibit non-competitively the adpg-synthesizing activities of the enzyme. upon substituting atp by either gtp or utp, and tris by hepes, we found t ...	1991	1834479
surface charge-mediated effects of mg on k flux across the chloroplast envelope are associated with regulation of stromal ph and photosynthesis.	studies of spinacia oleracea l. were undertaken to characterize further how mg(2+) external to the isolated intact chloroplast interacts with stromal k(+), ph, and photosynthetic capacity. data presented in this report were consistent with the previously developed hypothesis that millimolar levels of external, unchelated mg(2+) result in lower stromal k(+), which somehow is linked to stromal acidification. stromal acidification directly results in photosynthetic inhibition. these effects were at ...	1991	16668438
tandem mass spectrometry identifies sites of three post-translational modifications of spinach light-harvesting chlorophyll protein ii. proteolytic cleavage, acetylation, and phosphorylation.	the photosynthetic membranes of spinach (spinacia oleracea l.) chloroplasts were incubated with [gamma-32p] atp. when the thylakoid membrane kinase was activated with light, the 25- and 27-kda forms of the light-harvesting chlorophyll a/b protein (lhc ii) were phosphorylated on their amino termini. treatment of the membranes with proteinase k or thermolysin released phosphopeptides which were purified by ferric ion affinity chromatography and reverse phase high performance liquid chromatography. ...	1991	1894641
properties of oxidized and reduced spinach (spinacia oleracea) chloroplast fructose-1,6-bisphosphatase activated by various agents.	fructose-1,6-bisphosphatase (fbpase) can be reduced and activated by either dithiothreitol or reduced thioredoxin. this activation is ph-dependent. an amino acid group with a pk value of 5.55 is involved in this process. both enzyme forms can also be stimulated by agents such as fructose 1,6-bisphosphate, mg2+, ca2+ and ca2+/fructose 1,6-bisphosphate. fbpase reduced by dithiothreitol is more strongly activated than the enzyme reduced by thioredoxin. the specificity constant (kcat./km) is enhance ...	1991	1654892
multiplicity of soluble glucan-synthase activity in spinach leaves: enzyme pattern and intracellular location.	buffer-extractable proteins from leaves of spinacia oleracea l. were separated by non-denaturing polyacrylamide gel electrophoresis. gels were stained for adenosine diphosphoglucose (adpglucose)-dependent glucan-synthase (gs) activity (ec 2.4.1.21). three major forms of activity were observed. no staining was detectable when adpglucose was replaced by an equimolar concentration of either uridine, guanosine or cytosine diphosphoglucose. two of the three gs forms exhibited both primed and citrate- ...	1991	24186345
amino acid and sucrose content determined in the cytosolic, chloroplastic, and vacuolar compartments and in the phloem sap of spinach leaves.	amino acid and sucrose contents were analyzed in the chloroplastic, cytosolic, and vacuolar compartments and in the phloem sap of illuminated spinach leaves (spinacia oleracea l.). the determination of subcellular metabolite distribution was carried out by nonaqueous fractionation of frozen and lyophilized leaf material using a novel three-compartment calculation method. the phloem sap was collected by aphid stylets which had been severed by a laser beam. subcellular analysis revealed that the a ...	1991	16668375
effect of microtubule stabilization on the freezing tolerance of mesophyll cells of spinach.	freezing, dehydration, and supercooling cause microtubules in mesophyll cells of spinach (spinacia oleracea l. cv bloomsdale) to depolymerize (me bartolo, jv carter, plant physiol [1991] 97: 175-181). the objective of this study was to determine whether the lt(50) (lethal temperature: the freezing temperature at which 50% of the tissue is killed) of spinach leaf tissue can be changed by diminishing the extent of microtubule depolymerization in response to freezing. also examined was how toleranc ...	1991	16668367
microtubules in mesophyll cells of nonacclimated and cold-acclimated spinach : visualization and responses to freezing, low temperature, and dehydration.	responses of cortical microtubules in spinach (spinacia oleracea l. cv bloomsdale) mesophyll cells to freezing, thawing, supercooling, and dehydration were assessed. microtubules were visualized using a modified procedure for indirect immunofluorescence microscopy. leaf sections of nonacclimated and cold-acclimated spinach were slowly frozen to various temperatures, fixed while frozen, and microtubules immunolabelled. both nonacclimated and cold-acclimated cells exhibited nearly complete microtu ...	1991	16668366
six independent losses of the chloroplast dna rpl2 intron in dicotyledons: molecular and phylogenetic implications.	previous studies have shown that in several angiosperms and the liverwort marchantia the chloroplast gene rpl2, encoding ribosomal protein l2, is interrupted by an intron, but that in spinach (spinacia oleracea, caryophyllales) this intron has been lost. we have determined the distribution of the rpl2 intron for 390 species representing 116 angiosperm families. filter hybridizations reveal that the intron is absent from the chloroplast genomes of all examined families of the caryophyllales, sugg ...	1991	28564183
solubilization, partial purification, and reconstitution of the glycolate/glycerate transporter from chloroplast inner envelope membranes.	the glycolate/glycerate transporter of spinach (spinacia oleracea l.) chloroplast inner envelope membranes was solubilized by treatment of the membranes with sodium cholate. mixtures of the cholate extracts and soy asolectin were subjected to gel filtration to remove the detergent. the reconstituted vesicles were frozen, thawed, and sonicated in a buffer that contained 10 millimolar d-glycerate and, usually, [(3)h]sucrose as an internal space indicator. the dilution of the vesicles into a medium ...	1991	16668298
regulation by ca of a cytosolic fructose-1,6-bisphosphatase from spinach leaves.	cytosolic fructose-1,6-bisphosphatase from spinach (spinacia oleracea l.) leaves was purified over 1700-fold. the final preparation was specific for fructose-1,6-bisphosphate in the presence of either mg(2+) or mn(2+), and was free of interfering enzyme activities. ca(2+) was an effector of fructose-1,6-bisphosphatase activity, and showed different kinetics, depending on whether mg(2+) or mn(2+) was used as cofactor. in the presence of 5 millimolar mg(2+), ca(2+) appeared as activator or as inhi ...	1991	16668293
compartmentation studies on spinach leaf peroxisomes : evidence for channeling of photorespiratory metabolites in peroxisomes devoid of intact boundary membrane.	in concurrence with earlier results, the following enzymes showed latency in intact spinach (spinacia oleracea l.) leaf peroxisomes: malate dehydrogenase (89%), hydroxypyruvate reductase (85%), serine glyoxylate aminotransferase (75%), glutamate glyoxylate aminotransferase (41%), and catalase (70%). in contrast, glycolate oxidase was not latent. aging of peroxisomes for several hours resulted in a reduction in latency accompanied by a partial solubilization of the above mentioned enzymes. the ex ...	1991	16668283
acyl carrier protein is conjugated to glutathione in spinach seed.	acyl carrier protein (acp) contains an essential sulfhydryl group in its phosphopantetheine prosthetic group. we have investigated the state of this sulfhydryl in developing and mature spinach seed (spinacia oleracea). seed extracts were separated on sodium dodecyl sulfate or native polyacrylamide gels, blotted to nitrocellulose, and probed with antibodies raised against spinach acp-i. in extracts of mature seeds prepared with reducing agents, acp-ii migrated as a single major band, whereas extr ...	1991	16668278
purification of udp-galactose: diacylglycerol galactosyltransferase from chloroplast envelopes of spinach (spinacia oleracea l.).	uridine 5'-diphosphate(udp)-galactose: 1,2-diacylglycerol 3-o-β-d-galactopyranosyltransferase (ec 2.4.1.46) is an integral protein of chloroplast envelope membranes from which it has been partially purified (covès et al., 1986, febs lett. 208, 401-406). we have worked out a purification procedure which after removal of peripheral membrane proteins, solubilization and two chromotographic steps allowed us to identify a 22-kda protein as the galactosyltransferase. enrichment of enzymatic activity w ...	1991	24194148
symport of proton and sucrose in plasma membrane vesicles isolated from spinach leaves.	the mechanism of sucrose transport was investigated in plasma membrane (pm) vesicles isolated from spinach (spinacia oleracea l.) leaves. pm vesicles were isolated by aqueous two-phase partitioning and were equilibrated in ph 7.8 buffer containing k(+). the vesicles rapidly accumulated sucrose in the presence of a transmembrane ph gradient (deltaph) with external ph set at 5.8. the uptake rate was slow at ph 7.8. the k(+)-selective ionophore, valinomycin, stimulated uptake in the presence of a d ...	1991	16668230