Publications

an electrochemical study of the factors responsible for modulating the reduction potential of putidaredoxin.	the gene coding for putidaredoxin has been synthesized using a combination of chemical and enzymatic methods and subsequently expressed in escherichia coli. the recombinant protein characterized by electronic spectroscopy, mass spectrometry, and electrochemistry was found to be identical to putidaredoxin obtained from pseudomonas putida. polylysine was found to promote the fast and reversible electrochemistry of putidaredoxin at negatively charged electrodes such as indium-doped tin oxide or gol ...	1999	10550696
incision at nucleotide insertions/deletions and base pair mismatches by the sp nuclease of spinach.	spinach leaves contain a highly active nuclease called sp. the purified enzyme incises single-stranded dna, rna, and double-stranded dna that has been destabilized by a-t-rich regions and dna lesions [strickland et al. (1991) biochemistry 30, 9749-9756]. this broad range of activity has suggested that sp may be similar to a family of nucleases represented by s1, p1, and the mung bean nuclease. however, unlike these single-stranded nucleases that require acidic ph and low ionic strength condition ...	1999	10026304
genetic analysis of large-sized rna 2 species of a tcm-like tobacco rattle virus source from spinach.	rna 2 of a tobacco rattle virus isolate from spinach (trv sp) resembles that of a recently described isolate from onion (trv on), but its orf 3 is much larger. naturally infected spinach apparently contains a second trv sp rna 2 species with a partially deleted orf 3 and an rna 1-like 3'-end which consists of c. 1500 nts and thus is much longer than in any other tobravirus rna 2 sequenced so far. rnas 2 of trv sp and on are closely related to that of trv tcm from tulip, but besides the additiona ...	1999	10226616
plant ribosome recycling factor homologue is a chloroplastic protein and is bactericidal in escherichia coli carrying temperature-sensitive ribosome recycling factor.	we have isolated a protein, mature rrfhcp, from chloroplasts of spinach (spinacia oleracea l.) that shows 46% sequence identity and 66% sequence homology with ribosome recycling factor (rrf) of escherichia coli. rrf recycles ribosomes through disassembly of the posttermination complex. from the cdna analysis and from the amino-terminal sequencing of the isolated protein, the mature rrfhcp was deduced to have a mr of 21,838 with 193 aa. it lacks the 78-aa chloroplast targeting sequence encoded by ...	1999	10318906
heterologous overexpression of membrane-anchored subunit ii of spinach chloroplast atp synthase and its detergent-free purification as a soluble protein.	subunit ii is one of the four nonidentical subunits of the membrane integral, proton-transporting moiety (cfo) of the chloroplast atp synthase. in chloroplasts of spinach leaves, it is the only nuclear-encoded cfo subunit. it has been deduced that cfoii is not an additional subunit typical for photosynthetic organisms with no counterpart in e. coli, but equivalent to e. coli subunit b (tiburzy, h.-j. and berzborn, r. j. (1997), z. naturforsch. 52c, 789-798). heterologous expression of subunit ii ...	1999	10349741
comparison of phylloquinone bioavailability from food sources or a supplement in human subjects.	phylloquinone (k) absorption was assessed in 22- to 30-y-old human subjects consuming a standard test meal [402 kcal (1682 kj), 27% energy from fat]. the absorption of phylloquinone, measured over a 9-h period as the area under the curve (auc), was higher (p < 0.01) after the consumption of a 500- microgram phylloquinone tablet [27.55 +/- 10.08 nmol/(l. h), n = 8] than after the ingestion of 495 microgram phylloquinone as 150 g of raw spinach [4.79 +/- 1.11 nmol/(l. h), n = 3]. less phylloquinon ...	1999	10356087
hyperoxia-induced changes in antioxidant capacity and the effect of dietary antioxidants.	we investigated, by measuring oxygen radical absorbance capacity (orac), whether hyperoxia causes alterations in antioxidant status and whether these alterations could be modulated by dietary antioxidants. rats were fed for 8 wk a control diet or a control diet supplemented with vitamin e (500 iu/kg) or with aqueous extracts (orac: 1.36 mmol trolox equivalents/kg) from blueberries or spinach and then were exposed to air or >99% o2 for 48 h. although the constituents of the extracts were not exte ...	1999	10368343
plant riboflavin biosynthesis. cloning, chloroplast localization, expression, purification, and partial characterization of spinach lumazine synthase.	lumazine synthase, which catalyzes the penultimate step of riboflavin biosynthesis, has been cloned from three higher plants (spinach, tobacco, and arabidopsis) through functional complementation of an escherichia coli auxotroph. whereas the three plant proteins exhibit some structural similarities to known microbial homologs, they uniquely possess n-terminal polypeptide extensions that resemble typical chloroplast transit peptides. in vitro protein import assays with intact chloroplasts and imm ...	1999	10419541
overexpression in escherichia coli and characterization of the chloroplast triosephosphate isomerase from spinach.	an important calvin cycle enzyme, chloroplast triosephosphate isomerase (cptpi) from spinach, has been cloned and expressed in up to 15% of the total cell protein using the p(l) expression vector in escherichia coli. an even higher level expression, up to 36% of the total protein, was achieved by replacing the nucleotide sequence between the ribosomal binding site and the initial codon, atg, with an at-rich sequence. computer modeling revealed that the moderate change in the standard free energy ...	1999	10425165
reversals of age-related declines in neuronal signal transduction, cognitive, and motor behavioral deficits with blueberry, spinach, or strawberry dietary supplementation.	ample research indicates that age-related neuronal-behavioral decrements are the result of oxidative stress that may be ameliorated by antioxidants. our previous study had shown that rats given dietary supplements of fruit and vegetable extracts with high antioxidant activity for 8 months beginning at 6 months of age retarded age-related declines in neuronal and cognitive function. the present study showed that such supplements (strawberry, spinach, or blueberry at 14.8, 9.1, or 18.6 gm of dried ...	1999	10479711
mössbauer and electron paramagnetic resonance studies of the cytochrome bf complex.	the (57)fe-enriched cytochrome bf complex has been isolated from hydrocultures of spinach. it has been studied at different redox states by optical, epr, and mössbauer spectroscopy. the mössbauer spectrum of the native complex at 190 k with all iron centers in the oxidized state reveals the presence of four different iron sites: low-spin ferric iron in cytochrome b [with an isomer shift (delta) of 0.20 mm/s, a quadrupole splitting (deltae(q)) of 1.77 mm/s, and a relative area of 40%], low-spin f ...	1999	10413471
mechanism of light regulation of rubisco: a specific role for the larger rubisco activase isoform involving reductive activation by thioredoxin-f.	rubisco activase is a nuclear-encoded chloroplast protein that is required for the light activation of ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) in vivo. in most plants examined to date, there are two isoforms of rubisco activase arising from alternative splicing that differ only at the carboxyl terminus. here we demonstrate with recombinant proteins that in arabidopsis the larger isoform has a unique role in the regulation of rubisco activity. at physiological ratios of adp/atp, ...	1999	10430961
structure of a histidine ligand in the photosynthetic oxygen-evolving complex as studied by light-induced fourier transform infrared difference spectroscopy.	fourier transform infrared (ftir) signals of a histidine side chain were identified in flash-induced s(2)/s(1) difference spectra of the oxygen-evolving complex (oec) of photosystem ii (ps ii) using ps ii membranes from globally (15)n-labeled spinach and ps ii core complexes from synechocystis cells in which both the imidazole nitrogens of histidine were selectively labeled with (15)n. a negative band at 1113-1114 cm(-1) was downshifted by 7 cm(-1) upon both global (15)n-labeling and selective [ ...	1999	10433727
expression of alfalfa mosaic virus coat protein in tobacco mosaic virus (tmv) deficient in the production of its native coat protein supports long-distance movement of a chimeric tmv.	alfalfa mosaic virus (almv) coat protein is involved in systemic infection of host plants, and a specific mutation in this gene prevents the virus from moving into the upper uninoculated leaves. the coat protein also is required for different viral functions during early and late infection. to study the role of the coat protein in long-distance movement of almv independent of other vital functions during virus infection, we cloned the gene encoding the coat protein of almv into a tobacco mosaic ...	1999	10051680
mrna degradation. a tale of poly(a) and multiprotein machines.	the escherichia coli rna degradosome is a multiprotein complex containing an endoribonuclease, polynucleotide phosphorylase and a dead-box rna helicase. a related complex has been described in the spinach chloroplast. the exosome and the mtexo complex have recently been described in yeast and it is likely that related complexes also exist in animal cells. this research suggests the widespread existence of sophisticated machines for the efficient degradation of messenger rna. the dead-box helicas ...	1999	10087930
effect of vegetable and carotenoid consumption on aberrant crypt multiplicity, a surrogate end-point marker for colorectal cancer in azoxymethane-induced rats.	epidemiological studies indicate that increased vegetable consumption reduces the risk of colorectal cancer mortality. in the present study we have investigated the effect of consumption of standard diets supplemented with freeze-dried vegetables (peas, spinach, sprouts and broccoli) and carotenoids (all-trans beta-carotene and palm oil carotenoid extract) on surrogate end-point markers for colorectal cancer in an azoxymethane-induced rat model. mean aberrant crypt multiplicity was reduced (19%) ...	1999	10590218
highly purified thermo-stable oxygen-evolving photosystem ii core complex from the thermophilic cyanobacterium synechococcus elongatus having his-tagged cp43.	the carboxyl terminus of the cp43 subunit of photosystem ii (psii) in the thermophilic cyanobacterium, synechococcus elongatus, was genetically tagged with six consecutive histidine residues to create a metal binding site on the psii supramolecular complex. the histidine-tagging enabled rapid isolation of an intact cyanobacterial psii core complex from dodecyl maltoside-solubilized thylakoids by a simple one-step ni(2+)-affinity column chromatography. the isolated core complex was in a dimeric f ...	1999	10682344
spinach chloroplast fructose-1,6-bisphosphatase: identification of the subtilisin-sensitive region and of conserved histidines.	chloroplast fructose-1,6-bisphosphatase (fbpase) is an essential enzyme in the photosynthetic pathway of carbon dioxide fixation into sugars. the properties of the chloroplast enzyme are clearly distinct from those of cytosolic gluconeogenic fbpases. light-dependent activation via a ferredoxin/thioredoxin system and insensitivity to inhibition by amp are unique characteristics of the chloroplast enzyme. however, preliminary amino acid sequence data (78 residues) have demonstrated that a signific ...	1999	2827742
isoforms of acyl carrier protein involved in seed-specific fatty acid synthesis.	seeds of coriandrum sativum (coriander) and thunbergia alata (black-eyed susan vine) produce unusual monoenoic fatty acids which constitute over 80% of the total fatty acids of the seed oil. the initial step in the formation of these fatty acids is the desaturation of palmitoyl-acp (acyl carrier protein) at the delta(4) or delta(6) positions to produce delta(4)-hexadecenoic acid (16:1(delta(4)) or delta(6)-hexadecenoic acid (16:1(delta(6)), respectively. the involvement of specific forms of acp ...	1999	10366274
nitrate and nitrite in vegetables on the danish market: content and intake.	the contents of nitrate and nitrite in lettuce, leek, potato, beetroot, chinese cabbage and white cabbage on the danish market were determined for 3 years in the period 1993-1997 as part of the danish food monitoring programme. these vegetables are supposed to provide the major contribution to the intake of nitrate from the diet. results for nitrate and nitrite in fresh and frozen spinach are also shown. the highest content of nitrate was found in lettuce followed by beetroot, chinese cabbage, f ...	1999	10656054
recycling of na in advanced life support: strategies based on crop production systems.	sodium is an essential dietary requirement in human nutrition, but seldom holds much importance as a nutritional element for crop plants. in advanced life support (als) systems, recycling of gases, nutrients, and water loops is required to improve system closure. if plants are to play a significant role in recycling of human wastes, na will need to accumulate in edible tissues for return to the crew diet. if crops fail to accumulate the incoming na into edible tissues, na could become a threat t ...	1999	11542242
immobilization of p450 monooxygenase and chloroplast for use in light-driven bioreactors.	p450 monooxygenases exhibit great potential for application to bioreactors for the decomposition of various hydrophobic chemicals including pollutant compounds. p450-containing microsomes were immobilized in spinach chloroplasts for use in light-driven bioreactors. we tested three methods (entrapment, adsorption and cross-linking) to immobilize chloroplasts and yeast microsomes containing a genetically engineered fusion enzyme between rat p450 1a1 and yeast p450 reductase. entrapment in agarose ...	1999	16232556
purification and some molecular properties of rice germ calmodulin.	calmodulin (cam) from rice germ (oryza sativa l) was purified to homogeneity by hydrophobic interaction chromatography and gel filtration. the protein showed a single spot by sds-page. this purified protein had multiple absorption maxima at 276~279, 268, 265, 258, and 253 nm. like other plant cam, the protein contained one mole of tm3lys, cysteine, and tyrosine, and tryptophan was not detected. hydrophobic properties of rice germ, spinach, and neurospora crassa cam were directly tested by an hpl ...	1998	27388650
determination of soil-to-plant transfer factors of 137cs and 90sr in the tropical environment of bangladesh.	soil-to-plant transfer factors (tf) of 137cs and 90sr have been determined for different plants/crops, such as rice, beans, peanuts, pineapple, cabbage, tomato, spinach and grass. they were obtained from radioisotope experiments on plants grown in pots under outdoor ambient tropical conditions for three growing seasons (1994-1996). in the case of 137cs and concerning the above mentioned plants/crops, the average tfs were found to be 0.28, 0.25, 0.77, 0.19, 0.23, 0.28, 0.59 and 0.18, respectively ...	1998	9728745
molecular and biochemical characterization of cytosolic phosphoglucomutase in maize. expression during development and in response to oxygen deprivation.	phosphoglucomutase (pgm) catalyzes the interconversion of glucose (glc)-1- and glc-6-phosphate in the synthesis and consumption of sucrose. we isolated two maize (zea mays l.) cdnas that encode pgm with 98.5% identity in their deduced amino acid sequence. southern-blot analysis with genomic dna from lines with different pgm1 and pgm2 genotypes suggested that the cdnas encode the two known cytosolic pgm isozymes, pgm1 and pgm2. the cytosolic pgms of maize are distinct from a plastidic pgm of spin ...	1998	9662542
photooxidation of the cytochrome b-559 in the presence of various substituted 2-anilinothiophenes and of some other compounds, in chlamydomonas reinhardtii.	five substituted 2-anilinothiophenes and two substituted carbonylcyanide-phenylhydrazones were comparatively studied with respect to their capacities for inducing photooxidation of the cytochrome b-559 in chloroplast fragments and in whole cells of chlamydomonas reinhardtii (wild type and p-700-lacking mutant fl 5). in addition, some other compounds: antimycin a, picric acid, tetraphenylboron and nh4cl were also tested. cytochrome b-559 photooxidations were clearly observed in the presence of 2- ...	1998	508733
osmotic stress induces expression of choline monooxygenase in sugar beet and amaranth.	choline monooxygenase (cmo) catalyzes the committing step in the synthesis of glycine betaine, an osmoprotectant accumulated by many plants in response to salinity and drought. to investigate how these stresses affect cmo expression, a spinach (spinacia oleracea l., chenopodiaceae) probe was used to isolate cmo cdnas from sugar beet (beta vulgaris l., chenopodiaceae), a salt- and drought-tolerant crop. the deduced beet cmo amino acid sequence comprised a transit peptide and a 381-residue mature ...	1998	9489025
determination of nabam fungicide in crops by liquid chromatography with postcolumn reaction detection.	the ethylenebisdithiocarbamate (ebdc) fungicide, nabam, was determined in several crop matrixes using liquid chromatography with postcolumn reaction detection. after separation by micellar liquid chromatography, nabam (ebdc sodium salt) was acid hydrolyzed to ethylenediamine and fluorigenically labeled with o-phthalaldehyde-mercaptoethanol (opa-merc). standard curves were linear from the detection limit of ca 1 ng to 1000 ng. nabam was recovered in high yield (89 plus or minus 7.7%) over a range ...	1998	1904852
[thermal inactivation and storage behavior of technologically important enzymes. iv. spinach lipid-acyl-hydrolase].	the thermal reaction of a lipid-acyl-hydrolase which seems to be important for the quality preservation of vegetable foods, was investigated in spinach. the authors applied a simple in-situ method using thin-layer chromatography which had been developed for the enzyme determination, to follow the thermal inactivation of the lipid-acyl-hydrolase by measuring the decomposition of lecithin, mono- und digalactosyl diglycerides. according to the inactivation curves, the enzyme is relatively little re ...	1998	19886
a phosphothreonine residue at the c-terminal end of the plasma membrane h+-atpase is protected by fusicoccin-induced 14-3-3 binding.	we have isolated the plasma membrane h+-atpase in a phosphorylated form from spinach (spinacia oleracea l.) leaf tissue incubated with fusicoccin, a fungal toxin that induces irreversible binding of 14-3-3 protein to the c terminus of the h+-atpase, thus activating h+ pumping. we have identified threonine-948, the second residue from the c-terminal end of the h+-atpase, as the phosphorylated amino acid. turnover of the phosphate group of phosphothreonine-948 was inhibited by 14-3-3 binding, sugg ...	1998	9765540
nadh-monodehydroascorbate oxidoreductase is one of the redox enzymes in spinach leaf plasma membranes	amino acid analysis of internal sequences of purified nadh-hexacyanoferrate(iii) oxidoreductase (nforase), obtained from highly purified plasma membranes (pm) of spinach (spinacia oleracea l.) leaves, showed 90 to 100% homology to internal amino acid sequences of monodehydroascorbate (mda) reductases (ec 1.6.5.4) from three different plant species. specificity, kinetics, inhibitor sensitivity, and cross-reactivity with anti-mda reductase antibodies were all consistent with this identification. t ...	1998	9501135
adp-glucose pyrophosphorylase from potato tubers. site-directed mutagenesis studies of the regulatory sites.	several lysines (lys) were determined to be involved in the regulation of the adp-glucose (glc) pyrophosphorylase from spinach leaf and the cyanobacterium anabaena sp. pcc 7120 (k. ball, j. preiss [1994] j biol chem 269: 24706-24711; y. charng, a.a. iglesias, j. preiss [1994] j biol chem 269: 24107-24113). site-directed mutagenesis was used to investigate the relative roles of the conserved lys in the heterotetrameric enzyme from potato (solanum tuberosum l.) tubers. mutations to alanine of lys- ...	1998	9733546
protective effects of fruits and vegetables against in vivo clastogenicity of cyclosphosphamide or benzo[a]pyrene in mice.	seven fruits and 10 vegetables commonly consumed in germany were investigated for their anticlastogenic potencies against cyclophosphamide (cp) and benzo[a]pyrene (bap) in the in vivo mouse bone marrow micronucleus assay. we detected protective effects in 76.5% and 70.6% of the samples, respectively, and more or less distinct quantitative differences between the various plant materials and the two clastogens investigated. with respect to cp, moderate activities were exerted by sweet cherries, st ...	1998	9734714
long-term dietary strawberry, spinach, or vitamin e supplementation retards the onset of age-related neuronal signal-transduction and cognitive behavioral deficits.	recent research has indicated that increased vulnerability to oxidative stress may be the major factor involved in cns functional declines in aging and age-related neurodegenerative diseases, and that antioxidants, e.g., vitamin e, may ameliorate or prevent these declines. present studies examined whether long-term feeding of fischer 344 rats, beginning when the rats were 6 months of age and continuing for 8 months, with diets supplemented with a fruit or vegetable extract identified as being hi ...	1998	9742171
trienzyme treatment for food folate analysis: optimal ph and incubation time for alpha-amylase and protease treatment.	recent reports have indicated that trienzyme treatment before folate determination is essential to obtain the proper folate content in foods. trienzyme treatment is performed by using alpha-amylase and protease for folate extraction from carbohydrate and protein matrices, and folate conjugase for the hydrolysis of polyglutamyl folates. we evaluated the conditions of ph and incubation time for the treatment with alpha-amylase and protease. four food items, including fresh beef, white bread, cow's ...	1998	9742457
expression, purification, and characterization of recombinant ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit nepsilon-methyltransferase.	ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) large subunit (ls) nepsilon-methyltransferase (rubisco lsmt, ec 2.1.1.127) catalyzes methylation of the ls of rubisco. a pea (pisum sativum l. cv laxton's progress no. 9) rubisco lsmt cdna was expressed in escherichia coli, but most of the expressed protein was found in the insoluble fraction as an inclusion body. expression at lower temperatures increased the level of soluble rubisco lsmt and the associated enzymatic activity. however, t ...	1998	9758757
the carboxyl-terminal tripeptide of the manganese-stabilizing protein is required for quantitative assembly into photosystem ii and for high rates of oxygen evolution activity.	the extrinsic manganese stabilizing protein of photosystem ii is required for mn retention by the o2-evolving complex, accelerates the rate of o2 evolution, and protects photosytem ii against photoinhibition. we report results from studies of the in vitro reconstitution of spinach photosytem ii with recombinant manganese stabilizing protein with c-terminal deletions of two, three, and four amino acids. the deletions were the result of amber mutations introduced by site-directed mutagenesis. remo ...	1998	9760261
novel defensin subfamily from spinach (spinacia oleracea).	antimicrobial peptides (so-d1-7) were isolated from a crude cell wall preparation from spinach leaves (spinacia oleracea cv. matador) and, judged from their amino acid sequences, six of them (so-d2-7) represented a novel structural subfamily of plant defensins (group iv). group-iv defensins were also functionally distinct from those of groups i-iii. they were active at concentrations < 20 microm against gram-positive (clavibacter michiganensis) and gram-negative (ralstonia solanacearum) bacteria ...	1998	9762899
ribose-5-phosphate isomerase from saccharomyces cerevisiae: purification and molecular analysis of the enzyme.	purification and molecular analysis of ribose-5-phosphate isomerase (ec 5.3.1.6) from saccharomyces cerevisiae is described first time. the enzyme was enriched from a haploid deletion mutant containing the wild-type gene on a multicopy plasmid elaborating the following steps: ammonium sulphate precipitation, interfacial salting out on sepharose 6b, high performance liquid chromatography on fractogel emd deae and on resource phenyl. the enzyme activity was found to be rather unstable possibly cau ...	1998	9763699
a novel, non-redox-regulated nad-dependent malate dehydrogenase from chloroplasts of arabidopsis thaliana l.	we report a novel plastidic nad-dependent malate dehydrogenase (ec 1. 1.1.37), which is not redox-regulated in contrast to its nadp-specific counterpart (ec 1.1.1.82). analysis of isoenzyme patterns revealed a single nad-mdh associated with highly purified chloroplasts isolated from arabidopsis and spinach. a cdna clone encoding the novel enzyme was found in the arabidopsis est data base by sorting all putative clones for nad-dependent malate dehydrogenase. a derived amino acid sequence is very ...	1998	9774405
fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes.	it has been suggested that eating green leafy vegetables, which are rich in lutein and zeaxanthin, may decrease the risk for age related macular degeneration. the goal of this study was to analyse various fruits and vegetables to establish which ones contain lutein and/or zeaxanthin and can serve as possible dietary supplements for these carotenoids.	1998	9828775
the crystal structure of nadph:ferredoxin reductase from azotobacter vinelandii.	nadph:ferredoxin reductase (avfpr) is involved in the response to oxidative stress in azotobacter vinelandii. the crystal structure of avfpr has been determined at 2.0 a resolution. the polypeptide fold is homologous with six other oxidoreductases whose structures have been solved including escherichia coli flavodoxin reductase (ecfldr) and spinach, and anabaena ferredoxin:nadp+ reductases (fnr). avfpr is overall most homologous to ecfldr. the structure is comprised of a n-terminal six-stranded ...	1998	9865948
a novel approach for the crystallization of soluble proteins using non-ionic surfactants.	crystallization trials using three polyoxyethylene surfactants as precipitating agents are described. of the eight soluble proteins screened, five were successfully crystallized at the first attempt. these included lysozyme, catalase, ferritin, ribonuclease a and ubiquitin. further work suggested that these surfactants could also be suitable for cryo-crystallographic analysis of crystals. at the concentrations used in the crystallization trials [10-40%(v/v)], they are capable of promoting the fo ...	1998	9867432
not enough spinach?		1998	10408929
serum antioxidant capacity is increased by consumption of strawberries, spinach, red wine or vitamin c in elderly women.	it is often assumed that antioxidant nutrients contribute to the protection afforded by fruits, vegetables, and red wine against diseases of aging. however, the effect of fruit, vegetable and red wine consumption on the overall antioxidant status in human is unclear. in this study we investigated the responses in serum total antioxidant capacity following comsumption of strawberries (240 g), spinach (294 g), red wine (300 ml) or vitamin c (1250 mg) in eight elderly women. total antioxidant capac ...	1998	9868185
analysis of plastid dna-like sequences within the nuclear genomes of higher plants.	a wide-ranging examination of plastid (pt)dna sequence homologies within higher plant nuclear genomes (promiscuous dna) was undertaken. digestion with methylation-sensitive restriction enzymes and southern analysis was used to distinguish plastid and nuclear dna in order to assess the extent of variability of promiscuous sequences within and between plant species. some species, such as gossypium hirsutum (cotton), nicotiana tabacum (tobacco), and chenopodium quinoa, showed homogenity of these se ...	1998	9615455
molecular characterisation of the 76 kda iron-sulphur protein subunit of potato mitochondrial complex i.	genes encoding subunits of complex i (ec 1.6.5.3) of the mitochondrial respiratory chain vary in their locations between the mitochondrial and nuclear genomes in different organisms, whereas genes for a homologous multisubunit complex in chloroplasts have to date only been found on the plastid genome. in potato (solanum tuberosum l.), the gene coding for the mitochondrial 76 kda iron-sulphur protein is identified in the nuclear genome. the gene is transcribed into polyadenylated mrna which is mo ...	1998	9615461
the role of acyl carrier protein isoforms from cuphea lanceolata seeds in the de-novo biosynthesis of medium-chain fatty acids.	to investigate the role of acyl carrier protein (acp) in determining the fate of the acyl moieties linked to it in the course of de-novo fatty acid biosynthesis in higher plants, we carried out in vitro experiments to reconstitute the fatty acid synthase (fas) reaction in extracts of spinach (spinacia oleracea l.) leaves, rape (brassica napus l.) seeds and cuphea lanceolata ait. seeds. the action of two major c. lanceolata acp isoforms (acp 1 and acp 2) compared to acp from escherichia coli was ...	1998	9637071
in vivo antigenotoxic effects of dietary agents and beverages co-administered with urethane: assessment of the role of glutathione s-transferase activity.	antigenotoxic effects and changes in glutathione s-transferase (gst) activity were assessed in mice after oral co-administration of urethane (ure) with aqueous extracts of dietary vegetables (carrot, spinach and cabbage), spices (cinnamon, pepper, cumin, clove and cardamom), tea and coffee. the results of the genotoxicity assay (micronucleus test) demonstrated dose-related antigenotoxic effects after ure was co-administered with aqueous extracts of vegetables, spices, tea and coffee. inhibition ...	1998	9639686
electrophysiological evidence for the typicality effect of human cognitive categorization.	event-related brain potentials (erps) were recorded from 14 normal subjects during a category verification task. stimulus words were selected from 17 semantic categories (e.g. 'vegetables'). half of the words were typical category members (e.g. 'carrot', 'spinach') and the other half were atypical (e.g. 'parsley', 'asparagus'). subjects were required to judge whether each stimulus belonged to a target category ('vegetables' or 'sports') or a non-target category. for the non-target category, the ...	1998	9641249
eubacterial origin of nuclear genes for chloroplast and cytosolic glucose-6-phosphate isomerase from spinach: sampling eubacterial gene diversity in eukaryotic chromosomes through symbiosis.	higher plants possess two distinct nuclear-encoded glucose-6-phosphate isomerase (gpi) isoenzymes, a cytosolic enzmye of the embden-meyerhof pathway and a chloroplast enzyme essential to storage and mobilization of carbohydrate fixed by the calvin cycle. we have purified spinach chloroplast gpi to homogeneity, determined amino acid sequences from the active enzyme, and cloned cdnas for chloroplast and cytosolic gpi isoenzymes from spinach. sequence comparisons reveal three distantly related fami ...	1998	9651529
characterisation of an arabidopsis cdna encoding a thylakoid lumen protein related to a novel 'pentapeptide repeat' family of proteins.	we have cloned an arabidopsis cdna encoding a novel thylakoid lumen protein, p17.4, that has been previously isolated from lumen extracts of spinach chloroplasts. the protein is synthesised with a bipartite presequence containing a sec-type lumen-targeting signal peptide and the precursor protein is imported into the lumen of pea chloroplasts. the encoded protein is homologous to an anabaena protein that is essential for correct glycolipid localisation, and is also related to at least 16 unassig ...	1998	9654141
electrospray-ionization mass spectrometry of intact intrinsic membrane proteins.	membrane proteins drive and mediate many essential cellular processes making them a vital section of the proteome. however, the amphipathic nature of these molecules ensures their detailed structural analysis remains challenging. a versatile procedure for effective electrospray-ionization mass spectrometry (esi-ms) of intact intrinsic membrane proteins purified using reverse-phase chromatography in aqueous formic acid/isopropanol is presented. the spectra of four examples, bacteriorhodopsin and ...	1998	9655347
3-hydroxy-3-methylglutaryl-coenzyme a reductase kinase and sucrose-phosphate synthase kinase activities in cauliflower florets: ca2+ dependence and substrate specificities.	plant 3-hydroxy-3-methylglutaryl-coa reductase(hmgr; ec 1.1.1.34) and sucrose-phosphate synthase (sps; ec 2.4.1.14) and synthetic peptides designed from the known phosphorylation sites of plant hmgr (sams*: kshmkynrstkdvk), rat acetyl-coa carboxylase (sams: hmrsamsglhlvkrr), spinach sps (sp2: grrjrrissvejjdkk), and spinach nadh:nitrate reductase (nr6: gptlkrtastpfjnttsk) were used to characterize kinase activities from cauliflower (brassica oleracea l. ) inflorescences. the three major peaks of ...	1998	9675040
spinach csp41, an mrna-binding protein and ribonuclease, is homologous to nucleotide-sugar epimerases and hydroxysteroid dehydrogenases.	spinach csp41 is part of a protein complex that binds to the 3' untranslated region (utr) of petd precursor-mrna, a chloroplast gene encoding subunit iv of the cytochrome b6/f complex. csp41 cleaves the 3'-utr of petd mrna within the stem-loop structure, suggesting a key role in the control of chloroplast mrna stability. we discovered that csp41 is homologous to nucleotide-sugar epimerases and hydroxysteroid dehydrogenases while seeking distant homologs of these enzymes with a hidden markov mode ...	1998	9675122
hydrogen bonding of redox-active tyrosine z of photosystem ii probed by ftir difference spectroscopy.	the tyrz./tyrz ftir difference spectrum is reported for the first time in mn-depleted photosystem ii (ps ii)-enriched membranes of spinach, in ps ii core complexes of synechocystis sp. pcc 6803 wt, and in the mutant lacking tyrd (d2-tyr160phe). in synechocystis, the v7'a(co) and delta(coh) infrared modes of tyrz are proposed to account at 1279 and 1255 cm-1. the frequency of these modes indicate that tyrz is protonated at ph 6 and involved in a strong hydrogen bond to the side chain of a histidi ...	1998	9692943
molecular characterization and physiological role of a glyoxysome-bound ascorbate peroxidase from spinach.	cdnas encoding two cytosolic and two chloroplastic ascorbate peroxidase (asap) isozymes from spinach have been cloned recently [ishikawa et al. (1995) febs lett. 367: 28, (1996) febs lett. 384: 289]. we herein report the cloning of the fifth cdna of an asap isozyme which localizes in spinach glyoxysomes (gasap). the open reading frame of the 858-base pair cdna encoded 286 amino acid residues with a calculated molecular mass of 31,507 da. by determination of the latency of asap activity in intact ...	1998	9516999
vascular movement of beet necrotic yellow vein virus in beta macrocarpa is probably dependent on an rna 3 sequence domain rather than a gene product.	rnas 1 and 2 of beet necrotic yellow vein virus (bnyvv) carry the functions enabling viral rna replication, cell-to-cell movement, virus assembly and vascular movement of the virus in the systemic host spinacea oleracea. in beta macrocarpa, on the other hand, bnyvv rna 3 is required for vascular movement. replication-competent rna 3 transcripts carrying various point mutations and deletions were coinnoculated with rnas 1 and 2 to young leaves of b. macrocarpa and the ability of the virus to mult ...	1998	9472625
correlation between protein flexibility and electron transfer from qa-* to qb in psii membrane fragments from spinach.	to analyze a possible correlation between the extent of qa-* reoxidation and protein dynamics, fluorometric and mössbauer spectroscopic measurements were performed in photosystem ii membrane fragments from spinach. numerical evaluation of the flash-induced change of the normalized fluorescence quantum yield revealed that the extent of reoxidation starts to decrease below 275 k and is almost completely suppressed at 230 k. detailed analyses of mössbauer spectra measured at different temperatures ...	1998	9708974
investigation of the ability of proteolytic clostridium botulinum to multiply and produce toxin in fresh italian pasta.	the ability of proteolytic clostridium botulinum (types a, b, and f) to produce toxin in filled fresh italian pasta (tortelli) packed under a modified atmosphere was investigated. four types of tortelli (filled with artichoke, meat, ricotta-spinach, or salmon) were inoculated with a suspension of heat-shocked spores to give an initial concentration of approximately 10(3) spores per piece. samples were incubated at both 12 and 20 degrees c for up to 50 days and examined at selected time intervals ...	1998	9713759
immunization against rabies with plant-derived antigen.	we previously demonstrated that recombinant plant virus particles containing a chimeric peptide representing two rabies virus epitopes stimulate virus neutralizing antibody synthesis in immunized mice. we show here that mice immunized intraperitoneally or orally (by gastric intubation or by feeding on virus-infected spinach leaves) with engineered plant virus particles containing rabies antigen mount a local and systemic immune response. after the third dose of antigen, given intraperitoneally, ...	1998	9482911
d-ribulose-5-phosphate 3-epimerase: cloning and heterologous expression of the spinach gene, and purification and characterization of the recombinant enzyme.	we have achieved, to our knowledge, the first high-level heterologous expression of the gene encoding d-ribulose-5-phosphate 3-epimerase from any source, thereby permitting isolation and characterization of the epimerase as found in photosynthetic organisms. the extremely labile recombinant spinach (spinacia oleracea l.) enzyme was stabilized by dl-alpha-glycerophosphate or ethanol and destabilized by d-ribulose-5-phosphate or 2-mercaptoethanol. despite this lability, the unprecedentedly high sp ...	1998	9733539
a matrix-located processing peptidase of plant mitochondria.	nuclear-encoded mitochondrial precursor proteins are proteolytically processed inside the mitochondrion after import. the general mitochondrial processing activity in plant mitochondria has been shown to be integrated into the cytochrome bc1 complex of the respiratory chain. here we investigate the occurrence of an additional, matrix-located processing activity by incubation of the precursors of the soybean mitochondrial proteins, alternative oxidase, the fad subunit of the atp synthetase and th ...	1998	9484472
the role of aromatic and acidic amino acids in the electron transfer reaction catalyzed by spinach ferredoxin-dependent glutamate synthase.	treatment of the ferredoxin-dependent, spinach glutamate synthase with n-bromosuccinimide (nbs) modifies 2 mol of tryptophan residues per mol of enzyme, without detectable modification of other amino acids, and inhibits enzyme activity by 85% with either reduced ferredoxin or reduced methyl viologen serving as the source of electrons. the inhibition of ferredoxin-dependent activity resulting from nbs treatment arises entirely from a decrease in the turnover number. complex formation of glutamate ...	1998	9507092
a simple procedure for purifying the major chloroplast fructose-1,6-bisphosphatase from spinach (spinacia oleracea) and characterization of its stimulation by sub-femtomolar mercuric ions.	a rapid procedure for the purification of the redox-regulated chloroplast fructose-1,6-bisphosphatase [ec 3.1.3.11] from spinach leaf extract to homogeneity is described. no thiol-reducing agents were present during the purification and the enzyme is > 99% in the oxidized form. a rapid procedure to reduce and activate the fru-1,6-p2ase by dithiothreitol in the absence of thioredoxin is described. reduction activates the enzyme up to several hundred-fold when assayed at ph 8.0 with 2 mm mg2+. the ...	1998	9735161
purification, properties and in situ localization of the amphibolic enzymes d-ribulose 5-phosphate 3-epimerase and transketolase from spinach chloroplasts.	the amphibolic enzymes d-ribulose 5-phosphate 3-epimerase and transketolase have been purified from stroma extracts of spinach chloroplasts using ammonium sulfate fractionation and fplc. for the native enzymes, a molecular mass of 180 kda for epimerase and 160 kda for transketolase was found and the molecular masses of the subunits was determined to be 23 kda for epimerase and 74 kda for transketolase. protein sequencing of the purified chloroplast enzymes revealed the nh2-terminal amino acid se ...	1998	9523694
fluorescence resonance energy transfer mapping of subunit delta in spinach chloroplast f1 atpase.	despite the considerable progress in the field of f0f1-atpases caused by solving the 2.8-a structure of mitochondrial f1 atpase [abrahams, j. p., leslie, a. g. w., lutter, r. & walker, j. e. (1994) nature 370, 621-628], little is known about the position and function of the enzyme's small subunits which were not resolved in the x-ray analysis. we have previously genetically engineered cys residues into the delta subunit of chloroplast f1 and used these mutant subunits in cross-linking studies [l ...	1998	9523699
characterization of a gene for spinach cap160 and expression of two spinach cold-acclimation proteins in tobacco.	the cdna sequence for cap160, an acidic protein previously linked with cold acclimation in spinach (spinacia oleracea l.), was characterized and found to encode a novel acidic protein of 780 amino acids having very limited homology to a pair of arabidopsis thaliana stress-regulated proteins, rd29a and rd29b. the lack of similarity in the structural organization of the spinach and arabidopsis genes highlights the absence of a high degree of conservation of this cold-stress gene across taxonomic b ...	1998	9536054
the 23 and 17 kda extrinsic proteins of photosystem ii modulate the magnetic properties of the s1-state manganese cluster.	an s1-state parallel polarization "multiline" epr signal arising from the oxygen-evolving complex has been detected in spinach (psii) membrane and core preparations depleted of the 23 and 17 kda extrinsic polypeptides, but retaining the 33 kda extrinsic protein. this s1-state multiline signal, with an effective g value of 12 and at least 18 hyperfine lines, has previously been detected only in psii preparations from the cyanobacterium sp. synechocystis sp. pcc6803 [campbell, k. a., peloquin, j. ...	1998	9548734
cdna sequence and heterologous expression of monomeric spinach pullulanase: multiple isomeric forms arise from the same polypeptide.	the spinach pullulanase gene was cloned and sequenced using peptide sequences of the purified enzyme as a starting point and employing pcr techniques and cdna library screening. its open reading frame codes for a protein of 964 amino acids which represents a precursor of the pullulanase. the n-terminal transit peptide consists of 65 amino acids, and the mature protein, comprising 899 amino acids, has a calculated molecular mass of 99kda. pullulanase is a member of the alpha-amylase family. in ad ...	1998	9560325
optimization of the cleavage reaction for cyanylated cysteinyl proteins for efficient and simplified mass mapping.	peptide chains can be cleaved selectively on the n-terminal side of cysteine residues after cyanylation of sulfhydryl groups to form an amino-terminal peptide and a series of 2-iminothiazolidine-4-carboxyl peptides. this paper describes a systematic study that was carried out to elucidate the effects of peptide structure and reaction conditions on the kinetics of the reactions and the yields of cleavage products. both cleavage and beta-elimination reactions under different conditions (ph 8.0, 9. ...	1998	9570840
comparative study on recombinant chloroplastic and cytosolic ascorbate peroxidase isozymes of spinach.	the spinach stromal, thylakoid-bound, and cytosolic ascorbate peroxidase isozymes (ec 1.11.1.11) were overexpressed in escherichia coli, and their enzymatic properties were compared with the respective native isozymes. the purification of the recombinant stromal and cytosolic ascorbate peroxidases using the conventional column chromatography yielded 0.73 and 2.2 mg of protein/liter of bacteria culture with enzyme activities of 800 and 486 micromol min-1 mg protein-1, respectively. in every respe ...	1998	9578600
[characterization of aldehyde dehydrogenase gene fragment from mung bean vigna radiata using the polymerase chain reaction].	two degenerate oligonucleotide sequence primers and polymerase chain reactions on total dna have been utilized to clone on 651--bp gene fragment coding the central part of amino acid sequence of an earlier unknown aldehyde dehydrogenase (aldh) from mung bean. the deduced partial amino acid sequence for this aldehyde dehydrogenase shows about 65% sequence identity to aldhs of vibrio cholerae rhodococcus sp., alcaligenes eutrophus and about 45% sequence identity to mammalian aldhs 1 and 2, aldhs o ...	1998	9778740
characterization of protein-binding to the spinach chloroplast psba mrna 5' untranslated region.	rna-binding proteins play a major role in regulating mrna metabolism in chloroplasts. in this work we characterized two proteins, of 43 and 47 kda, which bind to the spinach psba mrna 5' untranslated region (psba encoding the d1 protein of photosystem ii). the 43 kda protein, which is present in the stroma and in membranes, co-sediments with a complex of 68s. it was purified, and the n-terminal sequence was determined. upon homology search it was identified as the chloroplast homologue of the es ...	1998	9580673
electron donation to the flavoprotein nifl, a redox-sensing transcriptional regulator.	transcriptional control of the nitrogen fixation (nif) genes in response to oxygen in azotobacter vinelandii is mediated by nitrogen fixation regulatory protein l (nifl), a regulatory flavoprotein that modulates the activity of the transcriptional activator nitrogen fixation regulatory protein a (nifa). cd spectra of purified nifl indicate that fad is bound to nifl in an asymmetric environment and the protein is predominantly alpha-helical. the redox potential of nifl is -226 mv at ph 8 as deter ...	1998	9601070
clp protease complexes and their diversity in chloroplasts.	the clp proteases represent a large, ancient atp-dependent protease family which in higher plants is known to be located in chloroplasts. the soluble, presumably multisubunit, enzyme of the organelle stroma is of dual genetic origin. it consists of a nuclear-encoded, regulatory subunit clpc, which is an atpase, and a plastid-encoded proteolytic subunit clpp, which is a serine protease. an additional, nuclear-encoded proteolytic subunit resembling clpp has been recently reported from tomato (scha ...	1998	9951729
the endogenous choline supply limits glycine betaine synthesis in transgenic tobacco expressing choline monooxygenase.	certain plants produce glycine betaine (glybet) in the chloroplast by a two-step oxidation of choline. introducing glybet accumulation into plants that lack it is a well-established target for metabolic engineering because glybet can lessen damage from osmotic stress. the first step in glybet synthesis is catalyzed by choline mono-oxygenase (cmo), a stromal enzyme with a rieske-type [2fe-2s] center. the absence of cmo is the primary constraint on glybet production in glybet-deficient plants such ...	1998	9881168
phytoestrogens and human health effects: weighing up the current evidence.	phytoestrogens are naturally occurring plant compounds which have oestrogenic and/or anti-oestrogenic activity. they are present in many human foodstuffs including beans, sprouts, cabbage, spinach, soyabean, grains and hops. the main classes are the isoflavones, coumestans and lignans. this review assesses the evidence that these substances may have adverse and/or beneficial impacts on the risk of several hormone-dependent diseases in humans. evidence from studies of various animal species has d ...	1998	9888630
membrane and receptor modifications of oxidative stress vulnerability in aging. nutritional considerations.	evidence suggests that oxidative stress (os) may contribute to the pathogenesis of age-related decrements in neuronal function and that os vulnerability increases as a function of age. in addition to decreased endogenous protection, increases in os vulnerability may result from changes in membrane lipids and distribution of receptor subtype. using a pc-12 cell model system, we have shown that h2o2 or dopamine (da) exposure induced deficits in the cell's ability to clear (extrude/sequester, e/s) ...	1998	9928436
the escherichia coli citrate carrier citt: a member of a novel eubacterial transporter family related to the 2-oxoglutarate/malate translocator from spinach chloroplasts.	under anoxic conditions in the presence of an oxidizable cosubstrate such as glucose or glycerol, escherichia coli converts citrate to acetate and succinate. two enzymes are specifically required for the fermentation of the tricarboxylic acid, i.e., a citrate uptake system and citrate lyase. here we report that the open reading frame (designated citt) located at 13.90 min on the e. coli chromosome between rna and the citrate lyase genes encodes a citrate carrier. e. coli transformed with a plasm ...	1998	9696764
transcription from heterologous rrna operon promoters in chloroplasts reveals requirement for specific activating factors.	the plastid rrna (rrn) operon in chloroplasts of tobacco (nicotiana tabacum), maize, and pea is transcribed by the plastid-encoded plastid rna polymerase from a sigma70-type promoter (p1). in contrast, the rrn operon in spinach (spinacia oleracea) and mustard chloroplasts is transcribed from the distinct pc promoter, probably also by the plastid-encoded plastid rna polymerase. primer-extension analysis reported here indicates that in arabidopsis both promoters may be active. to understand promot ...	1998	9701604
cloning and expression of the glgc gene from agrobacterium tumefaciens: purification and characterization of the adpglucose synthetase.	the gene encoding adpglucose synthetase (ec 2.7.7.27) from agrobacterium tumefaciens was isolated and expressed in escherichia coli. the recombinant protein was purified to electrophoretic homogeneity in steps including ion-exchange and hydrophobic chromatography. the same purification procedure was utilized to purify adpglucose synthetase from a. tumefaciens cells. the enzymes from the two sources were purified and characterized and were found to have identical kinetic, regulatory, and structur ...	1998	9721178
ilarviruses encode a cucumovirus-like 2b gene that is absent in other genera within the bromoviridae.	we found that rna 2 of the four ilarviruses sequenced to date encodes an additional conserved open reading frame (orf), 2b, that overlaps the 3' end of the previously known orf, 2a. a novel rna species of 851 nucleotides was found to accumulate to high levels in plants infected with spinach latent virus (splv). further analysis showed that rna 4a is a subgenomic rna of rna 2 and encodes all of orf 2b. moreover, a protein species of the size expected for splv orf 2b was translated in vitro from t ...	1998	9658153
related alphan- and epsilonn-methyltransferases methylate the large and small subunits of rubisco.	ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) is methylated at the ax amino position of the n-terminal methionyl residue of the processed and assembled form of the small subunit (ss), and is also methylated in some species at the epsilon-amino group of lysine-14 in the large subunit (ls). the gene (rbcmt-s) and cdnas for the ss alphan-methyltransferase (ssmt) from spinach (spinach oleracea) have been cloned, sequenced, and expressed. the gene is closely related to a previously charac ...	1998	10526959
release of two peripheral proteins from chloroplast thylakoid membranes in the presence of a hofmeister series of chaotropic anions.	the dissociation of two peripheral spinach (spinacia oleracea l.) thylakoid membrane proteins, coupling factor cf1 and ferredoxin-nadp+-oxidoreductase, in the presence of chaotropic sodium salts has been investigated, using monospecific antibodies against the proteins as probes. release of both proteins followed the hofmeister series of anions (cl- < no3- < br- < i- < scn-). in mixtures, the different salts had an additive effect. in addition, there were also qualitative differences in the actio ...	1998	9784254
purification of a nitrate reductase kinase from spinacea oleracea leaves, and its identification as a calmodulin-domain protein kinase.	spinach (spinacea oleracea l.) nitrate reductase (nr) is inactivated by phosphorylation on serine-543, followed by binding of the phosphorylated enzyme to 14-3-3 proteins. we purified one of several chromatographically distinct nrserine-543 kinases from spinach leaf extracts, and established by edman sequencing of 80 amino acid residues that it is a calcium-dependent (calmodulin-domain) protein kinase (cdpk), with peptide sequences very similar to arabidopsis cdpk6 (accession no. u20623; also kn ...	1998	9763711
oxygen permeability of thylakoid membranes: electron paramagnetic resonance spin labeling study.	oxygen transport in thylakoid membranes of spinach chloroplasts (spinacia oleracea) has been studied by observing the collisions of molecular oxygen with spin labels, using line broadening electron paramagnetic resonance (epr) spectroscopy. stearic acid spin labels were used to probe the local oxygen diffusion-concentration product. the free radical moiety was located at various distances from the membrane surface, and collision rates were estimated from linewidths of the epr spectra measured in ...	1998	9711298
interactions of proline, serine, and leucine with isolated spinach thylakoids: solute loading during freezing is not related to membrane fluidity.	we have investigated the physical mechanisms through which amino acids influence freeze-thaw damage to isolated spinach (spinacia oleracea l.) thylakoid membranes. the cryoprotective amino acid proline reduced osmotic membrane rupture during thawing by reducing solute loading of thylakoids during freezing for 1 h to -5 degreesc. evidence for binding of proline to the thylakoid surface was obtained by determining the partitioning of the hydrophobicity-sensitive dye merocyanine 540 between the bul ...	1998	9698434
potent inhibition of ribulose-bisphosphate carboxylase by an oxidized impurity in ribulose-1,5-bisphosphate	oxidation of d-ribulose-1,5-bisphosphate (ribulose-p2) during synthesis and/or storage produces d-glycero-2,3-pentodiulose-1, 5-bisphosphate (pentodiulose-p2), a potent slow, tight-binding inhibitor of spinach (spinacia oleracea l.) ribulose-p2 carboxylase/oxygenase (rubisco). differing degrees of contamination with pentodiulose-p2 caused the decline in rubisco activity seen during rubisco assay time courses to vary between different preparations of ribulose-p2. with some ribulose-p2 preparation ...	1998	9662549
spinach cytosolic fructose-1,6-bisphosphatase: ii. light effect on its expression.	the effect of light on the expression of spinach (spinacia oleracea) cytosolic fructose-1,6-bisphosphatase (fbpase) was determined by the level of mrna, protein content, and enzyme activity. it was found that its expression and activity were constant and stable during normal daily conditions as well as under continuous light or dark conditions. however, two different mrnas were detected; one transcript was expressed all the time, while the other was detected only during prolonged dark periods. a ...	1998	9638645
spinach cytosolic fructose-1,6-bisphosphatase: i. its organ-specific and developmental expression characteristics.	spinach (spinacia oleracea) cytosolic fructose-1,6-bisphosphatase (fbpase) was purified and the final preparation of protein has a specific activity of about 45 units/mg protein and a single band of molecular mass of 39 kda. polyclonal antibody against the protein did not cross-react with chloroplast fbpase, but showed strong cross-reactivity with all plant cytosolic fbpases tested. studies of the fbpase expression characteristics at early stages of development demonstrated that it was controlle ...	1998	9638644
effect of selenium supplementation on the uptake and translocation of chromium by spinach (spinacea oleracea).		1998	9595191
participation of mitochondrial metabolism in photorespiration. reconstituted system of peroxisomes and mitochondria from spinach leaves	in this study the interplay of mitochondria and peroxisomes in photorespiration was simulated in a reconstituted system of isolated mitochondria and peroxisomes from spinach (spinacia oleracea l.) leaves. the mitochondria oxidizing glycine produced serine, which was reduced in the peroxisomes to glycerate. the required reducing equivalents were provided by the mitochondria via the malate-oxaloacetate (oaa) shuttle, in which oaa was reduced in the mitochondrial matrix by nadh generated during gly ...	1998	9536050
heterogeneity and photoinhibition of photosystem ii studied with thermoluminescence	thermoluminescence (tl) signals were recorded from grana stacks, margins, and stroma lamellae from fractionated, dark-adapted thylakoid membranes of spinach (spinacia oleracea l.) in the absence and in the presence of 2,6-dichlorphenylindophenol (dcmu). in the absence of dcmu, the tl signal from grana fractions consisted of a homogenous b-band, which originates from recombination of the semi-quinone qb- with the s2 state of the water-splitting complex and reflects active photosystem ii (psii). i ...	1998	9501138
identification of a novel isoform of the chloroplast-coupling factor alpha-subunit.	studies were conducted to identify a 64-kd thylakoid membrane protein of unknown function. the protein was extracted from chloroplast thylakoids under low ionic strength conditions and purified to homogeneity by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. four peptides generated from the proteolytic cleavage of the wheat 64-kd protein were sequenced and found to be identical to internal sequences of the chloroplast-coupling factor (cf1) alpha-subunit. antibodies for th ...	1998	9489017
psby, a novel manganese-binding, low-molecular-mass protein associated with photosystem ii.	we describe two related manganese-binding polypeptides with l-arginine metabolizing enzyme activity that can be detected as distinct components (designated psby-a1 and psby-a2, previously called l-ame) in membranes containing photosystem ii (ps ii) from spinach. the polypeptides are bitopic and appear to exist in a heterodimeric form, but only in the chlorophyll a/b lineage of plants. both proteins are encoded in the nucleus. in spinach and in arabidopsis thaliana they are both derived from a si ...	1998	9829828
the nuclear rpl4 gene encodes a chloroplast protein that co-purifies with the t7-like transcription complex as well as plastid ribosomes.	we have cloned and sequenced the cdna and the gene coding for plastid ribosomal protein l4 (rpl4) from two higher plant species, spinach and arabidopsis thaliana. ribosomal protein l4 is one of the ribosomal proteins for which extraribosomal functions in transcriptional regulation has been demonstrated in prokaryotes. sequence comparison of the two plant cdnas and genes shows that the rpl4 gene has acquired a remarkable 3' extension during evolutionary transfer to the nuclear genome. this extens ...	1998	9461586
structure of the mutant e92k of [2fe-2s] ferredoxin i from spinacia oleracea at 1.7 a resolution.	ferredoxin i (fd i) from spinacia oleracea is composed of 97 amino-acid residues and a [2fe-2s] cluster. the crystal structure of the e92k mutant of fd i was solved by molecular replacement and refined to an r factor of 19.6% for 11755 reflections at 1.7 a resolution. the overall structure and the active centre of spinach fd is highly conserved with respect to ferredoxins of known structure. the e92k mutation appears to disturb a hydrogen-bond network which stabilizes the loop bearing the [2fe-2 ...	1998	10089511
protein heterogeneity of spinach pullulanase results from the coexistence of interconvertible isomeric forms of the monomeric enzyme.	purified pullulanase (starch-debranching enzyme, r-enzyme, ec 3.2.1. 41) from spinach (spinacia oleracea l.) chloroplasts separated into at least seven individual enzymically active proteins (isomers, numbered 1-7) on isoelectric focusing or column chromatofocusing. at their isoelectric points (between ph 4.7 and 5.2) these forms were rather stable. at slightly alkaline ph, each converted into the whole set of isomers. page of the purified enzyme under denaturing or non-denaturing conditions res ...	1998	9560324
salinity promotes accumulation of 3-dimethylsulfoniopropionate and its precursor s-methylmethionine in chloroplasts.	wollastonia biflora (l.) dc. plants accumulate the osmoprotectant 3-dimethylsulfoniopropionate (dmsp), particularly when salinized. dmsp is known to be synthesized in the chloroplast from s-methylmethionine (smm) imported from the cytosol, but the sizes of the chloroplastic and extrachloroplastic pools of these compounds are unknown. we therefore determined dmsp and smm in mesophyll protoplasts and chloroplasts. salinization with 30% (v/v) artificial seawater increased protoplast dmsp levels fro ...	1998	9449841