Publications

the expression of spinach glycolate oxidase (go) in e. coli and the application of go in the production of glyoxylic acid.	the complementary deoxyribonucleic acid (cdna) coding spinach glycolate oxidase (go) was amplified by reverse transcription polymerase chain reaction (rt-pcr), using the total ribonucleic acid (rna) of spinach leaves as the template, and was cloned into cloning vector pmd18-t. after the dna sequence was determined, the go gene was subcloned into escherichia coli expression vectors. sodium dodecyl sulfatepolyacrylamide gel electrophoresis (sds-page) analysis showed that recombinant go was express ...	2003	14668534
dissecting a cyanobacterial proteolytic system: efficiency in inducing degradation of the d1 protein of photosystem ii in cyanobacteria and plants.	a chromatography fraction, prepared from isolated thylakoids of a fatty acid desaturation mutant (fad6/desa colon, two colons km(r)) of the cyanobacterium synechocystis 6803, could induce an initial cleavage of the d1 protein in photosystem ii (psii) particles of synechocystis 6803 mutant and synechococcus 7002 wild type as well as in supercomplexes of psii-light harvesting complex ii of spinach. proteolysis was demonstrated both in darkness and in light as a reduction in the amount of full-leng ...	2003	14670603
optical spectra of synechocystis and spinach photosystem ii preparations at 1.7 k: identification of the d1-pheophytin energies and stark shifts.	we report and compare highly resolved, simultaneously recorded absorption and cd spectra of active photosystem ii (psii) samples in the range 440-750 nm. from an appropriately scaled comparison of spinach membrane fragment (bby) and psii core spectra, we show that key features of the core spectrum are quantitatively represented in the bby data. psii from the cyanobacterium synechocystis 6803 display spectral features in the qy region of comparable width (50-70 cm(-1) fwhm) to those seen in plant ...	2003	14570479
interaction of escherichia coli with growing salad spinach plants.	in this study, the interaction of a bioluminescence-labeled escherichia coli strain with growing spinach plants was assessed. through bioluminescence profiles, the direct visualization of e. coli growing around the roots of developing seedlings was accomplished. subsequent in situ glucuronidase (gus) staining of seedlings confirmed that e. coli had become internalized within root tissue and, to a limited extent, within hypocotyls. when inoculated seeds were sown in soil microcosms and cultivated ...	2003	14572215
role of 5-aminolevulinic acid (ala) on active oxygen-scavenging system in nacl-treated spinach (spinacia oleracea).	ala is a key precursor in the biosynthesis of porphyrins such as chlorophyll and heme, and was found to induce temporary elevations in the photosynthesis rate, apx, and cat; furthermore, treatment with ala at a low concentration might be correlated to the increase of nacl tolerance of spinach plants. the photosynthetic rate and the levels of active oxygen-scavenging system in the 3rd leaf of spinach (spinacia oleracea) plants grown by foliar treatment with 0, 0.18, 0.60 and 1.80 mmol/l 5-aminole ...	2003	14593810
mechanism of the reaction catalyzed by dehydroascorbate reductase from spinach chloroplasts.	dehydroascorbate reductase (dhar) reduces dehydroascorbate (dha) to ascorbate with glutathione (gsh) as the electron donor. we analyzed the reaction mechanism of spinach chloroplast dhar, which had a much higher reaction specificity for dha than animal enzymes, using a recombinant enzyme expressed in escherichia coli. kinetic analysis suggested that the reaction proceeded by a bi-uni-uni-uni-ping-pong mechanism, in which binding of dha to the free, reduced form of the enzyme was followed by bind ...	2003	12603325
complete spectra of the far-red chemiluminescence of the oxygenase reaction of mn2+-activated ribulose-bisphosphate carboxylase/oxygenase establish excited mn2+ as the source.	chemiluminescence emitted by mn(2+)-activated ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) while catalyzing oxygenation was analyzed to clarify the source of the emission. using dual detectors capturing radiation over a wide range of visible and infrared wavelengths, we tested for radiation from singlet o(2) decay and found it to be essentially absent (less than 0.1% of the total luminescence intensity). spectra were determined between 647 and 885 nm with a very sensitive, charge-co ...	2003	12604603
iodine uptake by spinach (spinacia oleracea l.) plants grown in solution culture: effects of iodine species and solution concentrations.	a hydroponic experiment was carried out to investigate the effects of iodine species and solution concentrations on iodine uptake by spinach (spinacia oleracea l.). five iodine concentrations (0, 1, 10, 50 and 100 microm) for iodate (io(3)(-)) and iodide (i(-)) were used. results show that higher concentrations of i(-) (> or =10 microm) had some detrimental effect on plant growth, while io(3)(-) had little effect on the biomass production of spinach plants. increases in iodine concentration in t ...	2003	12605934
reconstitution of water channel function of an aquaporin overexpressed and purified from pichia pastoris.	the aquaporin pm28a is one of the major integral proteins in spinach leaf plasma membranes. phosphorylation/dephosphorylation of ser274 at the c-terminus and of ser115 in the first cytoplasmic loop has been shown to regulate the water channel activity of pm28a when expressed in xenopus oocytes. to understand the mechanisms of the phosphorylation-mediated gating of the channel the structure of pm28a is required. in a first step we have used the methylotrophic yeast pichia pastoris for expression ...	2003	12606033
superoxide as an obligatory, catalytic intermediate in photosynthetic reduction of oxygen by adrenaline and dopamine.	the superoxide anion radical is known to be the first product of photosynthetic reduction of oxygen mediated by a variety of electron carriers. the effectiveness of many of these electron carriers as herbicides, and the toxicity of the superoxide they produce, have been suggested to rule out oxygen reduction as a physiological component of normal photosynthesis. here results with isolated spinach chloroplasts are presented that demonstrate that the related catecholamines adrenaline and dopamine ...	2003	12626112
a novel pcr method for identifying plankton in cases of death by drowning.	we present a new pcr method for identifying plankton in cases of death by drowning. we designed four primer pairs for chlorophyll-related genes of euglena gracilis (eg) and skeletonema costatum (sk), which are commonly distributed in water. the primers were selected from sequences coding chloroplast/chlorophyll apoprotein of eg (eg1 and eg2) and fucoxanthin-chlorophyll a/c harvesting protein of sk (sk1 and sk2). with eg1 or eg2, up to 2 fg of eg-dna was identified, and 0.2 pg of sk-dna was detec ...	2003	12627677
near-ir irradiation of the s2 state of the water oxidizing complex of photosystem ii at liquid helium temperatures produces the metalloradical intermediate attributed to s1y(z*).	near-ir (nir) excitation at liquid he temperatures of photosystem ii (psii) membranes from the cyanobacterium synechococcus vulcanus or from spinach poised in the s2 state results in the production of a g = 2.035 epr resonance, reminiscent of metalloradical signals. the signal is smaller in the spinach preparations, but it is significantly enhanced by the addition of exogenous quinones. ethanol (2-3%, v/v) eliminates the ability to trap the signal. the g = 2.035 signal is identical to the one re ...	2003	12627971
potential functional foods in the traditional maori diet.	the maori people were early new zealand settlers of polynesian descent. the incidence of non-infectious diseases appears to have been low in these people, perhaps in part due to the presence of protective chemical constituents within their food plant supply. three of the tropical crops they introduced are still eaten here today: the sweet potato or kumara (ipomoea batatas), the taro (colocasia esculenta) and the cabbage tree or ti (cordyline terminalis). sporamins a and b, the major storage prot ...	2003	12628508
purification of a plant nucleotide pyrophosphatase as a protein that interferes with nitrate reductase and glutamine synthetase assays.	an activity that inhibited both glutamine synthetase (gs) and nitrate reductase (nr) was highly purified from cauliflower (brassica oleracea var. botrytis) extracts. the final preparation contained an acyl-coa oxidase and a second protein of the plant nucleotide pyrophosphatase family. this preparation hydrolysed nadh, atp and fad to generate amp and was inhibited by fluoride, cu2+, zn2+ and ni2+. the purified fraction had no effect on the activity of nr when reduced methylviologen was used as e ...	2003	12631294
effect of rubiscolin, a delta opioid peptide derived from rubisco, on memory consolidation.	rubiscolin-6 (ypldlf) is a delta selective opioid peptide isolated from the enzymatic digests of ribulose bisphosphate carboxylase/oxygenase (rubisco) from spinach leaves. in a step-through type passive avoidance test in ddy mice, rubiscolin-6 enhanced memory consolidation at doses of 3nmol/mouse after intracerebroventricular administration, and at 100mg/kg after oral administration. these doses are smaller than the optimal doses for an analgesic effect. the memory enhancing effect of rubiscolin ...	2003	12668220
molecular characterization and redox regulation of phosphoribulokinase from the cyanobacterium synechococcus sp. pcc 7942.	we isolated and characterized a gene encoding phosphoribulokinase (prk) from synechococcus sp. pcc 7942. the isolated sequence consisted of a 999 bp open reading frame encoding 333 amino acid residues of prk. the prk contained a pair of cysteinyl residues corresponding to cys16 and cys55 of spinach prk regulated by a ferredoxin-thioredoxin system. however, there were seventeen amino acid residues lacking between the two cysteinyl residues compared with those of the chloroplastic enzyme in higher ...	2003	12668773
characterization of an ascorbate peroxidase in plastids of tobacco by-2 cells.	in higher plants, ascorbate peroxidase (apx; ec 1.11.1.11), the major h2o2-scavenging enzyme, occurs in several distinct isoenzymes that are localized in cytosol and various cell organelles. here, we have purified and characterized an apx from the soluble fraction of plastids of non-photosynthetic tobacco by-2 cells. the plastidic apx was a monomer with a molecular weight of 34 000. the enzymatic properties of the plastidic apx, including the rapid inactivation by h2o2 in ascorbate-depleted medi ...	2003	12675745
comparison of folate quantification in foods by high-performance liquid chromatography-fluorescence detection to that by stable isotope dilution assays using high-performance liquid chromatography-tandem mass spectrometry.	a comparison study on folate quantitation was carried out between the recently developed stable isotope dilution assay using liquid chromatography-tandem mass spectrometry (lc-ms-ms) and the frequently used hplc with fluorimetric detection (lc-fd). by applying lc-ms-ms, spinach, wheat bread, beef, and blood plasma were found to contain 159.2, 19.8, 1.2, and 5.6 microg/100 g total folates, respectively, whereas the respective quantitative data obtained by lc-fd were 95.5, 16.2, 0.7, and 6.8 micro ...	2003	12689834
crystal structure of class i acetohydroxy acid isomeroreductase from pseudomonas aeruginosa.	acetohydroxy acid isomeroreductase (ahir) is a key enzyme in the biosynthesis of branched-chain amino acids. we have determined the first crystal structure of a class i ahir from pseudomonas aeruginosa at 2.0 a resolution. its dodecameric architecture of 23 point group symmetry is assembled of six dimeric units and dimerization is essential for the formation of the active site. the dimeric unit of p.aeruginosa ahir partially superimposes with a three-domain monomer of spinach ahir, a class ii en ...	2003	12691757
dual coenzyme specificity of photosynthetic glyceraldehyde-3-phosphate dehydrogenase interpreted by the crystal structure of a4 isoform complexed with nad.	photosynthetic glyceraldehyde-3-phosphate dehydrogenase (gapdh) of spinacia oleracea belongs to a wide group of gapdhs found in most organisms displaying oxygenic photosynthesis, including cyanobacteria, green and red algae, and higher plants. as a major catalytic difference with respect to glycolytic gapdh, photosynthetic gapdh exhibits dual cofactor specificity toward pyridine nucleotides with a preference for nadp(h). here we report the crystal structure of nad-complexed recombinant a(4)-gapd ...	2003	12705826
native uridine 5'-diphosphate-sulfoquinovose synthase, sqd1, from spinach purifies as a 250-kda complex.	sulfoquinovosyldiacylglycerol is a polar lipid present in photosynthetic membranes. it contributes to the negative surface charge of the membrane and plays a pivotal role under phosphate stress. the sqd1 protein is the key enzyme involved in the formation of the sulfolipid head group precursor, uridine 5(')-diphosphate (udp)-sulfoquinovose, from udp-glucose and sulfite. a cdna encoding the spinach sqd1 protein was isolated and functionally expressed in escherichia coli. the recombinant enzyme wa ...	2003	12706349
dynamic interaction between the d1 protein, cp43 and oec33 at the lumenal side of photosystem ii in spinach chloroplasts: evidence from light-induced cross-linking of the proteins in the donor-side photoinhibition.	during the donor-side photoinhibition of spinach photosystem ii, the reaction center d1 protein cross-linked with the antenna chlorophyll binding protein cp43 of photosystem ii lacking the oxygen-evolving complex (oec) subunit proteins. the cross-linking did not occur upon illumination of photosystem ii samples that retained the oec33, nor when oec33-depleted photosystem ii samples were reconstituted with the oec33 prior to illumination. these results suggest that the d1 protein, cp43 and the oe ...	2003	12721387
overexpression of the sucrose transporter sosut1 in potato results in alterations in leaf carbon partitioning and in tuber metabolism but has little impact on tuber morphology.	the aim of this work was to examine the consequences of the heterologous expression of a spinach ( spinacia oleracea l.) sucrose transporter ( sosut1) in potato ( solanum tuberosum l.). many studies have indicated that reduction of the expression of this class of sucrose transporter has deleterious effects on plant growth and development; however, until now the possibility of improving plant performance by enhancing the expression of this sucrose transporter has not been reported. with this inte ...	2003	12721860
overexpression and reconstitution of a rieske iron-sulfur protein from the higher plant.	the iron-sulfur protein subunit, known as the rieske protein, is one of the central components of the cytochrome b(6)f complex residing in chloroplast and cyanobacterial thylakoid membranes. we have constructed plasmids for overexpression in escherichia coli of full-length and truncated rieske (petc) proteins from the spinacia oleracea fused to male. overexpressed fusion proteins were predominantly found (from 55 to 70%) in cytoplasm in a soluble form. the single affinity chromatography step (am ...	2003	12729720
concentrations of choline-containing compounds and betaine in common foods.	choline is important for normal membrane function, acetylcholine synthesis and methyl group metabolism; the choline requirement for humans is 550 mg/d for men (adequate intake). betaine, a choline derivative, is important because of its role in the donation of methyl groups to homocysteine to form methionine. in tissues and foods, there are multiple choline compounds that contribute to total choline concentration (choline, glycerophosphocholine, phosphocholine, phosphatidylcholine and sphingomye ...	2003	12730414
processing of vegetable-borne carotenoids in the human stomach and duodenum.	carotenoids are thought to diminish the incidence of certain degenerative diseases, but the mechanisms involved in their intestinal absorption are poorly understood. our aim was to obtain basic data on the fate of carotenoids in the human stomach and duodenum. ten healthy men were intragastrically fed three liquid test meals differing only in the vegetable added 3 wk apart and in a random order. they contained 40 g sunflower oil and mashed vegetables as the sole source of carotenoids. tomato pur ...	2003	12736146
developmental co-variation of rna editing extent of plastid editing sites exhibiting similar cis-elements.	in tobacco, 30 of 34 sites in chloroplast transcripts that undergo c-to-u rna editing can be grouped into clusters of 2-5 sites based on sequence similarities immediately 5' to the edited c. according to a previous transgenic analysis, overexpression of transcripts representing one cluster member results in reduction in editing of all cluster members, suggesting that members of an individual cluster share a trans-factor that is present in limiting amounts. to compare leaves and roots, we quantif ...	2003	12736308
the anabolic pyruvate oxidoreductase from methanococcus maripaludis.	in autotrophic methanogens, pyruvate oxidoreductase (por) plays a key role in the assimilation of co(2) and the biosynthesis of organic carbon. this enzyme has been purified to homogeneity, and the genes from methanococcus maripaludis were sequenced. the purified por contained five polypeptides with molecular masses of 47, 33, 25, 21.5 and 13 kda. the n-terminal sequences of four of the polypeptides had high similarity to the subunits commonly associated with this enzyme from other archaea. howe ...	2003	12743680
reversed-phase hplc determination of chlorophyll a' and phylloquinone in photosystem i of oxygenic photosynthetic organisms. universal existence of one chlorophyll a' molecule in photosystem i.	chlorophyll (chl) a', the c132-epimer of chl a, is a constituent of the primary electron donor (p700) of photosystem (ps) i of a thermophilic cyanobacterium synechococcus (thermosynechococcus) elongatus, as was recently demonstrated by x-ray crystallography. to determine whether ps i of oxygenic photosynthetic organisms universally contains one molecule of chl a', pigment compositions of thylakoid membranes and ps i complexes isolated from the cyanobacteria t. elongatus and synechocystis sp. pcc ...	2003	12755700
delta opioid peptides derived from plant proteins.	opioid peptides showing selectivity for delta receptor have been isolated from enzymatic digests of plant proteins. five peptides were derived from wheat gluten, and named gluten exorphins a5, a4, b5, b4 and c. two opioid peptides were also released from spinach ribulose-bisphosphate-carboxylase/oxygenase (rubisco), and named rubiscolins-5 and -6. among them, gluten exorphin 5a (gly-tyr-tyr-pro-thr) and rubiscolin 6 (tyr-pro-leu-asp-leu-phe) improved learning performance in step-through type pas ...	2003	12769740
opioid receptor ligands derived from food proteins.	during the last two decades a variety of food protein fragments has been demonstrated to elicit biological effects in various in vitro or in vivo test systems. a considerable part of these bioactive peptides are opioid receptor ligands, which may be regarded as exogenous supplements to the endogenous opioidergic systems of the human organism. most of these food-derived opioid receptor ligands are fragments of the milk proteins alpha-, beta- or kappa-casein, alpha-lactalbumin, beta-lactoglobulin ...	2003	12769741
non-watson-crick basepairing and hydration in rna motifs: molecular dynamics of 5s rrna loop e.	explicit solvent and counterion molecular dynamics simulations have been carried out for a total of >80 ns on the bacterial and spinach chloroplast 5s rrna loop e motifs. the loop e sequences form unique duplex architectures composed of seven consecutive non-watson-crick basepairs. the starting structure of spinach chloroplast loop e was modeled using isostericity principles, and the simulations refined the geometries of the three non-watson-crick basepairs that differ from the consensus bacteri ...	2003	12770867
inhibition of clastogenicity of benzo[a]pyrene and of its trans-7,8-dihydrodiol in mice in vivo by fruits, vegetables, and flavonoids.	in the in vivo mouse bone marrow micronucleus assay, homogenates of spinach, artichoke, peaches, and blue grapes as well as commercial concentrates of these vegetables and fruits reduced induction of micronuclei by benzo[a]pyrene (bap) by 43-50%. concentrates of strawberries (31% reduction) and of cauliflower (20% reduction) were less potent. inhibition of genotoxicity by spinach and peaches was not caused by any delay in maturation of micronucleated erythrocytes as shown by experiments with sam ...	2003	12787821
assessment of essential and toxic elements in some kinds of vegetables.	vegetables provide the human body with the essential bioavailable trace elements, and a constant supply of these various elements is necessary and highly recommended for daily life. minor elements such as ca, fe, k, mg, and na as well as trace elements such as cd, co, cu, mn, ni, pb, and zn were determined using an atomic absorption spectrophotometer in 12 different species of vegetables from saudi arabia (the al-taif district). these vegetables were cucumber, vegetable marrow, tomato, potato, g ...	2003	12798758
evidence of cytochrome p450-catalyzed cleavage of the ether bond of phenoxybutyrate herbicides in rhodococcus erythropolis k2-3.	bacterial strain rhodococcus erythropolis k2-3 can cleave the ether bond of the phenoxybutyrate herbicides, i.e., 4-(2,4-dichlorophenoxy)butyrate (2,4-db) and 4-(4-chloro-2-methylphenoxy)butyrate (mcpb), by an enzyme system that is constitutively expressed. the enzyme(s) involved were investigated in this study. the rate of disappearance of 2,4-db determined in a whole cell assay amounted to 0.6 mmol/h x g(dry mass). carbon monoxide difference spectra of dithionite-reduced whole cells and crude ...	2003	12801099
spinach makes a safer anthrax vaccine.		2003	12801787
the promoter of the spinach psaf gene for the subunit iii of the photosystem i reaction center directs beta-glucuronidase gene expression in transgenic tobacco roots. implication of the involvement of phospholipases and protein kinase c in psaf gene expression.	psaf is a nuclear encoded gene for the subunit iii of photosystem i. it is located at the lumenal side of the thylakoid membrane and interacts with plastocyanin. starting from a low-level expression in the cotyledons of etiolated seedlings the gene is upregulated by light. light can be replaced by ca2+ or phosphoinositides like phorbol myristate acetate, an analogue of diacylglycerol. we tested the effects of these components on psaf promoter-driven gene expression in roots and found that the ps ...	2003	12806778
field trials to assess the uptake of arsenic by vegetables from contaminated soils and soil remediation with iron oxides.	the uptake of arsenic (as) by plants from contaminated soils presents a health hazard that may affect the use of agricultural and former industrial land. methods for limiting the hazard are desirable. a proposed remediation treatment comprises the precipitation of iron (fe) oxides in the contaminated soil by adding ferrous sulfate and lime. the effects on as bioavailability were assessed using a range of vegetable crops grown in the field. four uk locations were used, where soil was contaminated ...	2003	12826380
proteomic characterization of the chlamydomonas reinhardtii chloroplast ribosome. identification of proteins unique to th e70 s ribosome.	we have conducted a proteomic analysis of the 70 s ribosome from the chlamydomonas reinhardtii chloroplast. twenty-seven orthologs of escherichia coli large subunit proteins were identified in the 50 s subunit, as well as an ortholog of the spinach plastid-specific ribosomal protein-6. several of the large subunit proteins of c. reinhardtii have short extension or insertion sequences, but overall the large subunit proteins are very similar to those of spinach chloroplast and e. coli. two protein ...	2003	12826678
isolation and characterization of agar-degrading paenibacillus spp. associated with the rhizosphere of spinach.	agar-degrading bacteria in spinach plant roots cultivated in five soils were screened, and four strains of paenibacillus sp. were isolated from roots cultivated in three soils. the agar-degrading bacteria accounted for 1.3% to 2.5% of the total bacteria on the roots. in contrast, no agar-degrading colony was detected in any soil (non-rhizosphere soil samples) by the plate dilution method, and thus these agar-degrading bacteria may specifically inhabit plant roots. all isolates produced extracell ...	2003	12834282
protocol for the production of concentrated extracts of food folate for use in human bioavailability studies.	to provide a tool to study folate bioavailability under controlled conditions, a methodology was developed to produce extracts representative of natural food folates but removed from their matrix and sufficiently concentrated so as to elicit a response in biomarkers of folate status without distorting usual dietary intake patterns. egg, spinach, and yeast were selected to represent the wide range in extent of folate conjugation found in foods (0, 60, and 100% polyglutamyl folate, respectively). ...	2003	12848514
application of stable isotope dilution assays based on liquid chromatography-tandem mass spectrometry for the assessment of folate bioavailability.	a pilot study was performed to prove the suitability of stable isotope dilution assays for assessing the bioavailability of endogenous folates in foods. by using [2h(4)]folic acid, [2h(4)]tetrahydrofolate, [2h(4)]5-methyltetrahydrofolate, [2h(4)]5-formyltetrahydrofolate and [2h(4)]10-formylfolic acid as internal standards, folates in spinach, apple juice and blood plasma were quantified by liquid chromatography coupled to tandem mass spectrometry. to liberate the pteroyl monoglutamates, sample e ...	2003	12860024
structure-activity relationship of rubiscolins as delta opioid peptides.	to study the structure-activity relationship of rubiscolins (ypldlf and ypldl), delta opioid peptides derived from the spinach rubisco, we substituted the amino acid residues and evaluated their activities by mouse vas deferens (mvd) and guinea pig ileum (gpi) assays as well as receptor affinity. replacement of leu(3) with ile and met in rubiscolin-6 potentiated the delta opioid activity by about four times in mvd assay. asp(4) cannot be replaced by ala, glu or his. the original leu(5) was optim ...	2003	12860192
characterization of native and recombinant a4 glyceraldehyde 3-phosphate dehydrogenase. kinetic evidence for confromation changes upon association with the small protein cp12.	a4 glyceraldehyde 3-phosphate dehydrogenase (gapdh) was purified from the green alga chlamydomonas reinhardtii and was also overexpressed in escherichia coli. both purified a4 tetramers of recombinant and native gapdh were characterized for the first time. the ph optimum for both native and recombinant enzymes was close to 7.8. the pks of the residues involved in catalysis indicate that a cysteine and a histidine may take part in catalysis by chloroplast gapdh, as is the case for glycolytic gapd ...	2003	12492483
effects of glycolipids from spinach on mammalian dna polymerases.	we purified the major glycolipids in the class of monogalactosyl diacylglycerol (mgdg), digalactosyl diacylglycerol (dgdg) and sulfoquinovosyl diacylglycerol (sqdg) from a green vegetable, spinach (spinacia oleracea l.). mgdg was an inhibitor of the growth of nugc-3 human gastric cancer cells, but dgdg and sqdg had no such cytotoxic effect. therefore, we studied mgdg and its monoacyglycerol-form, monogalactosyl monoacylglycerol (mgmg), in detail. mgmg with one fatty acid molecule was obtained fr ...	2003	12504801
nitric oxide-induced formation of the s-2 state in the oxygen-evolving complex of photosystem ii from synechococcus elongatus.	in spinach photosystem ii (psii) membranes, the tetranuclear manganese cluster of the oxygen-evolving complex (oec) can be reduced by incubation with nitric oxide at -30 degrees c to a state which is characterized by an mn(2)(ii, iii) epr multiline signal [sarrou, j., ioannidis, n., deligiannakis, y., and petrouleas, v. (1998) biochemistry 37, 3581-3587]. this state was recently assigned to the s(-)(2) state of the oec [schansker, g., goussias, c., petrouleas, v., and rutherford, a. w. (2002) bi ...	2003	12549922
chloroplast fructose 1,6-bisphosphatase with changed redox modulation: comparison of the galdieria enzyme with cysteine mutants from spinach.	spinach fructose 1,6-bisphosphatase (fbpase, ec 3.1.3.11), a redox-modulated chloroplast enzyme and part of the calvin cycle, and three different cys mutants were expressed in e. coli. the properties of the purified proteins were compared to those of native and recombinant chloroplast fbpase from the red alga galdieria sulphuraria. in spinach chloroplast fbpase, cys(155) and cys(174) are engaged in the formation of the disulfide bridge. the corresponding mutants are active when expressed in e. c ...	2003	12573251
slowing tumorigenic progression in tramp mice and prostatic carcinoma cell lines using natural anti-oxidant from spinach, nao--a comparative study of three anti-oxidants.	the tramp model and human prostatic cancer (pca) cell lines du145 and pc3 are useful forchemopreventive studies. we compared the efficacy of 3 anti-oxidants [a water-soluble natural anti-oxidant. nao (200 mg/kg). found in spinach leaves; epigallocatechin-3 gallate, egcg (200 mg/kg), a major green tea polyphenol; and n-acetylcysteine, nac (125 mg/kg)] plus vehicle in slowing spontaneous tumorigenic progression in tramp and wild-type male mice. sacrifices occurred on weeks 5, 9, and 13. prostatic ...	2003	12597448
functional differences of photosystem ii from synechococcus elongatus and spinach characterized by flash induced oxygen evolution patterns.	detailed comparative studies of flash induced oxygen evolution patterns in thylakoids from the thermophilic cyanobacterium synechococcus elongatus (s. elongatus; also referred to as thermosynechococcus elongatus) and from spinach led to the following results: (i) the miss parameter alpha of s. elongatus thylakoids exhibits a pronounced temperature dependence with a minimum of 7% at 25 degrees c and values of 17 and 10% at 3 and 35 degrees c, respectively, while for spinach thylakoids alpha decre ...	2003	12885225
two redox-active beta-carotene molecules in photosystem ii.	photosystem ii (ps ii) contains secondary electron-transfer paths involving cytochrome b(559) (cyt b(559)), chlorophyll (chl), and beta-carotene (car) that are active under conditions when oxygen evolution is blocked such as in inhibited samples or at low temperature. intermediates of the secondary electron-transfer pathways of ps ii core complexes from synechocystis pcc 6803 and synechococcus sp. and spinach ps ii membranes have been investigated using low temperature near-ir spectroscopy and e ...	2003	12885246
isolation and antihypertensive effect of angiotensin i-converting enzyme (ace) inhibitory peptides from spinach rubisco.	four new inhibitory peptides for angiotensin i-converting enzyme (ace), that is, mrwrd, mrw, lripva, and iaykpag, were isolated from the pepsin-pancreatin digest of spinach rubisco with the use of hplc. ic(50) values of individual peptides were 2.1, 0.6, 0.38, and 4.2 microm, respectively. mrw and mrwrd had an antihypertensive effect after oral administration to spontaneously hypertensive rats. maximal reduction occurred 2 h after oral administration of mrw, whereas mrwrd showed maximal decrease ...	2003	12903942
species-specific differences of the spectroscopic properties of p700: analysis of the influence of non-conserved amino acid residues by site-directed mutagenesis of photosystem i from chlamydomonas reinhardtii.	we applied optical spectroscopy, magnetic resonance techniques, and redox titrations to investigate the properties of the primary electron donor p700 in photosystem i (ps i) core complexes from cyanobacteria (thermosynechococcus elongatus, spirulina platensis, and synechocystis sp. pcc 6803), algae (chlamydomonas reinhardtii cc2696), and higher plants (spinacia oleracea). remarkable species-specific differences of the optical properties of p700 were revealed monitoring the (3p700-p700) and (p700 ...	2003	12933812
domain analysis of the chloroplast polynucleotide phosphorylase reveals discrete functions in rna degradation, polyadenylation, and sequence homology with exosome proteins.	the molecular mechanism of mrna degradation in the chloroplast consists of sequential events, including endonucleolytic cleavage, the addition of poly(a)-rich sequences to the endonucleolytic cleavage products, and exonucleolytic degradation. in spinach chloroplasts, the latter two steps of polyadenylation and exonucleolytic degradation are performed by the same phosphorolytic and processive enzyme, polynucleotide phosphorylase (pnpase). an analysis of its amino acid sequence shows that the prot ...	2003	12953107
refolding from denatured inclusion bodies, purification to homogeneity and simplified assay of mgdg synthases from land plants.	in plant cells, the synthesis of monogalactosyldiacylglycerol (mgdg) is catalyzed within plastid envelope membranes by mgd proteins. mgdg synthesis was also reported in apicomplexan parasites, a phylum of protists harbouring a plastid that proved essential for the parasite survival. mgd activity is therefore a potent target for herbicidal and anti-parasitic molecules. in this study, we describe a detailed in vitro refolding protocol for denatured recombinant mgd accumulated in inclusion bodies f ...	2003	12963344
the solution structure of the loop e region of the 5s rrna from spinach chloroplasts.	a structure has been obtained for the loop e region of the 5s rrna from spinacia oleracia chloroplast ribosomes using residual dipolar coupling data as well as noe, j coupling and chemical shift information. even though the loop e sequence of this chloroplast 5s rrna differs from that of escherichia coli loop e at approximately 40% of its positions, its conformation is remarkably similar to that of e.coli loop e. consistent with this conclusion, ribosomal protein l25 from e.coli, which binds to ...	2003	12527295
polycyclic aromatic hydrocarbons in a semiaquatic plant and semipermeable membrane devices exposed to air in thailand.	semipermeable membrane devices (spmds) were deployed at six sites in the bangkok region, thailand, to investigate spatial variations in atmospheric concentrations of polycyclic aromatic hydrocarbons (pahs). sampling sites affected by various levels of traffic intensity were studied. in addition, pah levels were determined in a common human food plant (water spinach) harvested from canals and ponds in the sampling areas. significant differences in atmospheric pah concentrations between sites were ...	2003	12542289
[old and new prescriptions for infectious diseases and the newest recipes for biomedical products in plants].	the three antiviral vaccines discovered in the 18th century (smallpox), 19th century (rabies), and 20th century (polio) share a common feature: none would ever be licensed today for human vaccination. yet jenner's smallpox vaccine led to the eradication of smallpox, pasteur's rabies vaccine represented the first successful post-exposure treatment of people bitten by rabid animals, and polio vaccine administered since its discovery in 1950 is leading to the eradication of polio (in the years 2004 ...	2002	12549429
[current researches on biological effect of aluminum].	aluminum content is generally not high (less that 10 mg/kg) in most foods with the exception of a few such as tea, spinach, and so on, that contain more amounts of it. however, aluminum content is much high in foods in those aluminum-containing food additives are used. after drinking water is treated with aluminum-containing coagulant agent, it's aluminum concentration increases. the aluminum intake of residents from cookware in our country is 4 mg/(capit.d). the aluminum intake in adults is usu ...	2002	12600050
calreticulin-like molecule in trophozoites of entamoeba histolytica hm1:imss (swissprot: accession p83003).	in this work, we report the partial sequence of a 51 kda protein of entamoeba histolytica that is highly immunogenic in humans. partial sequencing of the n-terminal end showed that 18 of the first 20 amino acid residues of the protein were identified uniquely, indicating that the final product was a homogeneous protein preparation. the n-terminal sequence that was found was: kvyfeetfengwkxiwskw. comparing the 19-amino acid sequence of the protein in automated databases shows significant similari ...	2002	12518855
the plant s-adenosyl-l-methionine:mg-protoporphyrin ix methyltransferase is located in both envelope and thylakoid chloroplast membranes.	chlorophyll biosynthesis requires a metabolic dialog between the chloroplast envelope and thylakoids where biosynthetic activities are localized. here, we report the first plant s-adenosyl-l-methionine:mg-protoporphyrin ix methyltransferase (mgp(ix)mt) sequence identified in the arabidopsis genome owing to its similarity with the synechocystis sp. mgp(ix)mt gene. after expression in escherichia coli, the recombinant arabidopsis thaliana cdna was shown to encode a protein having mgp(ix)mt activit ...	2002	11784318
a functional role for tyrosine-d in assembly of the inorganic core of the water oxidase complex of photosystem ii and the kinetics of water oxidation.	the role of d2-tyr160 (y(d)), a photooxidizable residue in the d2 reaction center polypeptide of photosystem ii (psii), was investigated in both wild type and a mutant strain (d2-tyr160phe) in which phenylalanine replaces y(d) in the cyanobacterium synechocystis sp. (strain pcc 6803). y(d) is the symmetry-related tyrosine that is homologous to the essential photoactive tyr161(y(z)) of the d1 polypeptide of psii. we compared the flash-induced yield of o(2) in intact, functional psii centers from ...	2002	11790121
thylakoid membrane-bound ascorbate peroxidase is a limiting factor of antioxidative systems under photo-oxidative stress.	to evaluate the physiological importance of thylakoid membrane-bound ascorbate peroxidase (tapx) in the active oxygen species-scavenging system of chloroplasts, the level of tapx in tobacco plants was altered by expression of the tapx cdna in both sense and antisense orientation. the tobacco plants transformed with constructs of antisense tapxs from spinach and tobacco could not be obtained, suggesting that the suppression of tapx in higher plants had a severe effect on the growth even under nor ...	2002	12492834
the effect of different cooking methods on folate retention in various foods that are amongst the major contributors to folate intake in the uk diet.	folate intake is strongly influenced by various methods of cooking that can degrade the natural forms of the vitamin in foods. the aim of the present study was to determine the effect of different cooking methods on folate retention in various foods that contribute to folate intake in the uk diet. typical purchasing and cooking practices of representative food folate sources were determined from a questionnaire survey of local shoppers (n 100). total folate was determined by microbiological assa ...	2002	12493090
relative immunogenicity of commonly allergenic foods versus rarely allergenic and nonallergenic foods in mice.	food allergies affect 6 to 8% of children and 2% of adults in the united states. for reasons that are not clear, eight types of food account for a vast majority (approximately 90%) of food-induced hypersensitivity reactions. in this study, c57bl/6 mice were used to test the hypothesis that commonly allergenic foods are intrinsically more immunogenic than rarely allergenic or nonallergenic foods in allergy-susceptible hosts. groups of mice (n = 4 to 5) were injected intraperitoneally with the pro ...	2002	12495022
antioxidant properties of differently processed spinach products.	the effect of variously processed spinach products (whole-leaf, minced and enzymatically liquefied spinach) on lipid oxidation was determined. in an autoxidative methyl linoleate (melo) system the inhibition of hydroperoxide formation, measured by hplc after three days of oxidation, was in descending order: whole-leaf > liquefied > minced spinach. the inhibition of formation of thiobarbituric acid-reactive substances (tbars) and hexanal by spinach was determined in cooked meatballs with added sp ...	2002	12224427
decreased hill reaction rates and slow turnover of transitory starch in the obligate shade plant panax quinquefolius l. (american ginseng).	to identify physiological processes that might limit photosynthesis in panax quinquefolius l. (american ginseng) a comparison has been made with panax ginseng c.a. meyer (korean ginseng), pisum sativum l. (pea) and spinacia oleracea l. (spinach). the quantum yield of oxygen evolution in intact leaves and isolated thylakoid membranes was found to be smaller in ginseng than in pea or spinach. however, the number of photosystem ii (psii) centers on a chlorophyll basis was found to be similar in all ...	2002	12355157
rebuilt 3d structure of the chloroplast f1 atpase-tentoxin complex.	the f1 part of the chloroplast h+ adenosine triphosphate (atp)-synthase (cf1) strongly interacts with tentoxin, a natural fungous cyclic tetrapeptide known to inhibit the chloroplast enzyme and not the mammalian mitochondrial enzyme. whereas the synthesis or the hydrolysis of atp requires the stepwise rotation of the protein rotor gamma within the (alphabeta)3 crown, only one molecule of tentoxin is needed to fully inhibit the complex. with the help of an original homology modeling technique, ba ...	2002	12360520
functional and structural adaptations of bacterial communities growing on particulate substrates under stringent nutrient limitation.	biomass recycle reactors (brrs) were used as a model system to study the functional and structural adaptations of mixed bacterial communities in response to the imposition of increasingly severe nutrient limitation. brrs were fed synthetic media containing either spinach homogenate or autoclaved yeast cells to simulate the complex mixtures of particulate carbon sources that are often present in nature. in the brrs fed spinach homogenate, the biomass (measured as particulate protein) exhibited a ...	2002	12399897
antioxidant and antiproliferative activities of common vegetables.	epidemiological studies have shown that consumption of fruits and vegetables is associated with reduced risk of chronic diseases. increased consumption of fruits and vegetables containing high levels of phytochemicals has been recommended to prevent chronic diseases related to oxidative stress in the human body. in this study, 10 common vegetables were selected on the basis of consumption per capita data in the united states. a more complete profile of phenolic distributions, including both free ...	2002	12405796
proteomic characterization of the small subunit of chlamydomonas reinhardtii chloroplast ribosome: identification of a novel s1 domain-containing protein and unusually large orthologs of bacterial s2, s3, and s5.	to understand how chloroplast mrnas are translated into functional proteins, a detailed understanding of all of the components of chloroplast translation is needed. to this end, we performed a proteomic analysis of the plastid ribosomal proteins in the small subunit of the chloroplast ribosome from the green alga chlamydomonas reinhardtii. twenty proteins were identified, including orthologs of escherichia coli s1, s2, s3, s4, s5, s6, s7, s9, s10, s12, s13, s14, s15, s16, s17, s18, s19, s20, and ...	2002	12417713
interactions between spinacia oleracea and bradysia impatiens: a role for phytoecdysteroids.	plant produced insect molting hormones, termed phytoecdysteroids (pes), are thought to function as plant defenses against insects by acting as either feeding deterrents or through developmental disruption. in spinach (spinacia oleracea), 20-hydroxyecdysone (20e) concentrations in the roots rapidly increase following root damage, root herbivory, or methyl jasmonate (mj) applications. in this inducible system, we investigated the plant defense hypothesis by examining interactions of roots, 20e con ...	2002	12432520
organization of transmembrane helices in photosystem ii: comparison of plants and cyanobacteria.	electron microscopy and x-ray crystallography are revealing the structure of photosystem ii. electron crystallography has yielded a 3d structure at sufficient resolution to identify subunit positioning and transmembrane organization of the reaction-centre core complex of spinach. single-particle analyses are providing 3d structures of photosystem ii-light-harvesting complex ii supercomplexes that can be used to incorporate high-resolution structural data emerging from electron and x-ray crystall ...	2002	12437871
protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip) in metabolically competent v79 cells.	chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome p450 dependent monooxygenase 1a2 and rat sulfotransferase 1c1 (v79-rcyp1a2-rsult1c1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (aaf) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip). antigenotoxic activities of juices from spinach and red beets against aaf could ...	2002	12438004
full subunit coverage liquid chromatography electrospray ionization mass spectrometry (lcms+) of an oligomeric membrane protein: cytochrome b(6)f complex from spinach and the cyanobacterium mastigocladus laminosus.	highly active cytochrome b(6)f complexes from spinach and the cyanobacterium mastigocladus laminosus have been analyzed by liquid chromatography with electrospray ionization mass spectrometry (lcms+). both size-exclusion and reverse-phase separations were used to separate protein subunits allowing measurement of their molecular masses to an accuracy exceeding 0.01% (+/-3 da at 30,000 da). the products of peta, petb, petc, petd, petg, petl, petm, and petn were detected in complexes from both spin ...	2002	12438564
thermodynamics of the acid transition in blue copper proteins.	the thermodynamic parameters of the conformational transition occurring at low ph (acid transition, at) in blue copper proteins, involving protonation and detachment from the cu(i) ion of one histidine ligand, have been determined electrochemically for spinach and cucumber plastocyanins, rhus vernicifera stellacyanin, cucumber basic protein (cbp), and paracoccus versutus amicyanin. these data were obtained from direct protein electrochemistry experiments carried out at varying ph and temperature ...	2002	12450394
polyribosome loading of spinach mrnas for photosystem i subunits is controlled by photosynthetic electron transport.	in light-, but not in dark-grown spinach seedlings, the mrnas for the nuclear-encoded photosystem i subunits d, f and l are associated with polyribosomes and this association is prevented by the application of 3-(3',4'-dichlorophenyl)-1,1'-dimethyl urea (dcmu), an inhibitor of the photosynthetic electron transport. to identify the cis-elements which are responsible for this regulation, we generated a series of chimeric psad constructs and tested them in transgenic tobacco. the spinach psad 5'-un ...	2002	12472681
exceptional stability of a [2fe-2s] ferredoxin from hyperthermophilic bacterium aquifex aeolicus.	aquifex aeolicus is the only hyperthermophile that is known to contain a plant- and mammalian-type [2fe-2s] ferredoxin (aae fd1). this unique protein contains two cysteines, in addition to the four that act as ligands of the [2fe-2s] cluster, which form a disulfide bridge. we have investigated the stability of aae fd1 with (wild-type) and without (c87a variant) the disulfide bond, with respect to ph, thermal and chemical perturbation, and compared the results to those for the mesophilic [2fe-2s] ...	2002	12479408
polyphenolic allelochemicals from the aquatic angiosperm myriophyllum spicatum inhibit photosystem ii.	myriophyllum spicatum (haloragaceae) is a highly competitive freshwater macrophyte that produces and releases algicidal and cyanobactericidal polyphenols. among them, beta-1,2,3-tri-o-galloyl-4,6-(s)-hexahydroxydiphenoyl-d-glucose (tellimagrandin ii) is the major active substance and is an effective inhibitor of microalgal exoenzymes. however, this mode of action does not fully explain the strong allelopathic activity observed in bioassays. lipophilic extracts of m. spicatum inhibit photosynthet ...	2002	12481084
differential regulation of rna levels of gibberellin dioxygenases by photoperiod in spinach.	previous work with spinach (spinacia oleracea) has shown that the level of gibberellin (ga) 20-oxidase is strongly up-regulated by long days (ld). in the present work, the effect of photoperiod on expression of other ga dioxygenases was investigated and compared with that of ga 20-oxidase. two ga 2-oxidases and one ga 3-oxidase were isolated from spinach by reverse transcription-polymerase chain reaction with degenerate primers and by 5'- and 3'-rapid amplification of cdna ends. as determined by ...	2002	12481092
[comparative study of the biological utilization of beta-carotene from synthetic and natural sources in rats].	the purpose of this study was to evaluate the change in concentration of retinol and beta-carotene (bc) in blood serum and liver tissue of rats, after supplementation with synthetic bc and commonly consumed carotenoid-rich vegetables (carrot and spinach). weanling male wistar rats were randomly assigned in four groups of 16 rats each. the four groups of rats were supplemented according to the following feeding treatments: 1) control group (0g), 0.2 ml corn oil; 2) pure bc group (bcg), 60 microgr ...	2002	12868275
cloning of the o-acetylserine lyase gene from the ruminal bacterium selenomonas ruminantium hd4.	the gene coding for o-acetylserine lyase (oasl) was cloned from a selenomonas ruminantium hd4 lambda zap ii genomic library by degenerative probe hybridization and complementation. sequence analysis revealed a 933 bp orf with a g + c content of 53%. the orf had significant homology with enzymes involved in cysteine biosynthesis. a curablastn homology search showed that the orf shared 59% nucleotide identity with the cysk of bacillus subtilis. the deduced amino acid sequence exhibited high (>70%) ...	2002	11821922
magneto-optical measurements of the pigments in fully active photosystem ii core complexes from plants.	preparation of a minimum psii core complex from spinach is described, containing four mn per reaction center (rc) and exhibiting high o2 evolving activity [approximately 4000 micromol of o2 (mg of chl)(-1) x h(-1)]. the complex consists of the cp47 and cp43 chlorophyll binding proteins, the rc d1/d2 pair, the cytochrome b559 subunits, and the mn-stabilizing psbo (33 kda) protein, all present in the same stoichiometric amounts found in the parent psii membranes. several small subunits are also pr ...	2002	11827545
the role of glycine betaine in the protection of plants from stress: clues from transgenic plants.	the acclimation of a plant to a constantly changing environment involves the accumulation of certain organic compounds of low molecular mass, known collectively as compatible solutes, in the cytoplasm. the evidence from numerous investigations of the physiology, genetics, biophysics and biochemistry of plants strongly suggests that glycine betaine (gb), an amphoteric quaternary amine, plays an important role as a compatible solute in plants under various types of environmental stress, such as hi ...	2002	11841661
small changes in the activity of chloroplastic nadp(+)-dependent ferredoxin oxidoreductase lead to impaired plant growth and restrict photosynthetic activity of transgenic tobacco plants.	a ferredoxin-nadp+ oxidoreductase (fnr) cdna from tobacco (nicotiana tabacum cv. samsun) was cloned and sequenced. comparison of the deduced amino acid sequence revealed high identity to fnr proteins from capsicum annuum, pisum sativum, spinacia oleracea and vicia faba. transgenic tobacco plants were generated that constitutively express the fnr cdna in reverse orientation between the camv 35s promoter and the polyadenylation signal of the octopine synthase gene. plants expressing the fnr antise ...	2002	11844106
modulation of cyanoalanine synthase and o-acetylserine (thiol) lyases a and b activity by beta-substituted alanyl and anion inhibitors.	the reaction mechanisms of three enzymes belonging to a single gene family are compared: a cyanoalanine synthase and two isoforms of o-acetylserine (thiol) lyase (o-astl) isolated from spinach (spinacea oleracea l. cv. medina). o-astl represents a major regulatory point in the s-assimilatory pathway, and the related cyanoalanine synthase, which is specific to the mitochondrial compartment, has evolved an independent function of cyanide detoxification. all three enzymes catalysed both the cystein ...	2002	11847242
kinetic properties of bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase from spinach leaves.	a cdna encoding 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was isolated from a spinacia oleracea leaf library and used to express a recombinant enzyme in escherichia coli and spodoptera frugiperda cells. the insoluble protein expressed in e. coli was purified and used to raise antibodies. western blot analysis of a protein extract from spinach leaf showed a single band of 90.8 kda. soluble protein was purified to homogeneity from s. frugiperda cells infected with recombinant baculoviru ...	2002	11856361
identification of aminoethylcysteine ketimine decarboxylated dimer, a natural antioxidant, in dietary vegetables.	aminoethylcysteine ketimine decarboxylated dimer (simply named dimer) is a natural sulfur-containing tricyclic compound detected, until now, in human urine, bovine cerebellum, and human plasma. recently, the antioxidant properties of this compound have been demonstrated. in this investigation, the presence of aminoethylcysteine ketimine decarboxylated dimer was identified in garlic, spinach, tomato, asparagus, aubergine, onion, pepper, and courgette. identification of this compound in dietary ve ...	2002	11902974
structure of spinach chloroplast f1-atpase complexed with the phytopathogenic inhibitor tentoxin.	tentoxin, a natural cyclic tetrapeptide produced by phytopathogenic fungi from the alternaria species affects the catalytic function of the chloroplast f(1)-atpase in certain sensitive species of plants. in this study, we show that the uncompetitive inhibitor tentoxin binds to the alphabeta-interface of the chloroplast f(1)-atpase in a cleft localized at betaasp-83. most of the binding site is located on the noncatalytic alpha-subunit. the crystal structure of the tentoxin-inhibited cf(1)-comple ...	2002	11904410
molecular characterization of nucleus-localized rna-binding proteins from higher plants.	we report the isolation and characterization of genes from the higher plants arabidopsis, spinach and tobacco which code for nucleus-localized rna-binding proteins. common features of these polypeptides are glycine/arginine-rich regions with several rgg repeats at their n- and c-termini, which are sufficient for rna binding in northwestern assays. all polypeptides analysed contain two basic bipartite nuclear localization signals and translational fusions harbouring these regions with the beta-gl ...	2002	11905967
interaction of cytosolic and plastidic nitrogen metabolism in plants.	in angiosperms, the assimilation of ammonia resulting from nitrate reduction and from photorespiration depends on the operation of the plastidic gs/gogat cycle. the precursor for ammonia assimilation, 2-oxoglutarate, is synthesized in the mitochondria and in the cytosol. it is imported into the plastid by a 2-oxoglutarate/malate translocator (dit1). in turn, the product of ammonia assimilation, glutamate, is exported from the plastids by a glutamate/malate translocator (dit2). these transport pr ...	2002	11912229
assembly of photosystem i. i. inactivation of the ruba gene encoding a membrane-associated rubredoxin in the cyanobacterium synechococcus sp. pcc 7002 causes a loss of photosystem i activity.	a 4.4-kb hindiii fragment, encoding an unusual rubredoxin (denoted ruba), a homolog of the synechocystis sp. pcc 6803 gene slr2034 and arabidopsis thaliana hcf136, and the psbeflj operon, was cloned from the cyanobacterium synechococcus sp. pcc 7002. inactivation of the slr2034 homolog produced a mutant with no detectable phenotype and wild-type photosystem (ps) ii levels. inactivation of the ruba gene of synechococcus sp. pcc 7002 produced a mutant unable to grow photoautotrophically. ruba and ...	2002	11914373
the plant-specific function of 2-cys peroxiredoxin-mediated detoxification of peroxides in the redox-hierarchy of photosynthetic electron flux.	the 2-cysteine peroxiredoxins (2-cys prx) constitute an ancient family of peroxide detoxifying enzymes and have acquired a plant-specific function in the oxygenic environment of the chloroplast. immunocytochemical analysis and work with isolated intact chloroplasts revealed a reversible binding of the oligomeric form of 2-cys prx to the thylakoid membrane. the oligomeric form of the enzyme was enhanced under stress. the 2-cys prx has a broad substrate specificity with activity toward hydrogen pe ...	2002	11929977
microcosm wetlands for wastewater treatment with different hydraulic loading rates and macrophytes.	constructed wetlands (cw) usually require large land areas for treating wastewater. this study evaluated the feasibility of applying cw with less land requirement by operating a group of microcosm wetlands at a hydraulic retention time (hrt) of less than 4 d in southern taiwan. an artificial wastewater, simulating municipal wastewater containing 200 mg l(-1) of chemical oxygen demand (cod), 20 mg l(-1) of nh4+-n (an), and 20 mg l(-1) of po4(3-)-p (op), was the inflow source. three emergent plant ...	2002	11931463
electron crystallographic study of photosystem ii of the cyanobacterium synechococcus elongatus.	the determination of the structure of psii at high resolution is required in order to fully understand its reaction mechanisms. two-dimensional crystals of purified highly active synechococcus elongatus psii dimers were obtained by in vitro reconstitution. images of these crystals were recorded by electron cryo-microscopy, and their analysis revealed they belong to the two-sided plane group p22(1)2(1), with unit cell parameters a = 121 a, b = 333 a, and alpha = 90 degrees. from these crystals, a ...	2002	11955064
fruit polyphenolics and brain aging: nutritional interventions targeting age-related neuronal and behavioral deficits.	nutritional interventions, in this case, increasing dietary intake of fruits and vegetables, can retard and even reverse age-related declines in brain function and in cognitive and motor performance in rats. our lab has shown that as fischer 344 rats age their brains are increasingly vulnerable to oxidative stress. dietary supplementation with fruit or vegetable extracts high in antioxidants (e.g., blueberry, bb, spinach, respectively) can decrease this vulnerability to oxidative stress as asses ...	2002	11976192
comparison of the structure of the extrinsic 33 kda protein from different organisms.	the psbo gene encoding the extrinsic 33 kda protein of oxygen-evolving photosystem ii (psii) complex was cloned and sequenced from a red alga, cyanidium caldarium. the gene encodes a polypeptide of 333 residues, of which the first 76 residues served as transit peptides for transfer across the chloroplast envelope and thylakoid membrane. the mature protein consists of 257 amino acids with a calculated molecular mass of 28,290 da. the sequence homology of the mature 33 kda protein was 42.9-50.8% b ...	2002	11978871
the rate of charge recombination in photosystem ii.	loss by recombination of the charge separated state p(680+)q(a-) limits the performance of photosystem ii (ps ii) as a photochemical energy converter. time constants reported in literature for this process are mostly either near 0.17 ms or near 1.4 ms. the shorter time is found in plant ps ii when reduction of p(680+) by the secondary electron donor tyrosine z cannot occur because y(z) is already oxidized. the 1.4 ms recombination is seen in y(z)-less mutants of the cyanobacterium synechocystis. ...	2002	11997139
the antioxidant activity of regularly consumed fruit and vegetables reflects their phenolic and vitamin c composition.	recent studies are emphasising the importance and putative modes of action of specific flavonoids as bioactive components of the diet in in vivo and in vitro models. thus, it is important to have a clear idea of the major phenolic families of which fruit and vegetables are comprised and the levels contained therein. regularly consumed fruit and vegetables of mixed varieties available on the uk market were analysed for the composition of the major individual phenolic components. the total phenoli ...	2002	11999391
possible antitumor promoters in spinacia oleracea (spinach) and comparison of their contents among cultivars.	spinach leaves were found to contain two potent antitumor promoters as detected by the activity against tumor promoter-induced epstein-barr virus activation. the active components were identified as 1-o-alpha-linolenoyl-2-o-(7z,10z,13z)-hexadecatrienoyl-3-o-beta-d-galactopyranosyl-sn-glycerol and 1,2-di-o-alpha-linolenoyl-3-o-beta-d-galactopyranosyl-sn-glycerol by spectroscopic data and some chemical and enzymatic reactions. their contents significantly varied with the cultivar and with the cult ...	2002	11999395
molecular and biochemical characterization of a cold-regulated phosphoethanolamine n-methyltransferase from wheat.	a cdna that encodes a methyltransferase (mt) was cloned from a cold-acclimated wheat (triticum aestivum) cdna library. molecular analysis indicated that the enzyme wpeamt (wheat phosphoethanolamine [p-ea] mt) is a bipartite protein with two separate sets of s-adenosyl-l-met-binding domains, one close to the n-terminal end and the second close to the c-terminal end. the recombinant protein was found to catalyze the three sequential methylations of p-ea to form phosphocholine, a key precursor for ...	2002	12011366