Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| the superiority of organically cultivated vegetables to general ones regarding antimutagenic activities. | we found organically cultivated (oc) vegetables, using a water-soluble chitosan as a soil improvement agent and leaf surface spray, had much longer shelf life and better taste than that of generally cultivated (gc) vegetables. the purpose of this study is to determine the relative antimutagenic activity between oc and gc vegetables. eleven oc vegetables were harvested in march and april in 1999 and 2000, and gc ones were supplied as a control from nearby farms on the same date. the former vegeta ... | 2001 | 11551483 |
| comprehensive survey of proteins targeted by chloroplast thioredoxin. | possible target proteins of chloroplast thioredoxin (trx) have been investigated in the stroma lysate of spinach chloroplasts. for that purpose, we immobilized a mutant of m-type trx in which an internal cysteine at the active site was substituted with serine, on cyanogen bromide-activated resin. by using this resin, the target proteins in chloroplast were efficiently acquired when they formed the mixed-disulfide intermediates with the immobilized trxs. we could acquire rubisco activase (45 kda) ... | 2001 | 11553771 |
| a role for rubredoxin in oxidative stress protection in desulfovibrio vulgaris: catalytic electron transfer to rubrerythrin and two-iron superoxide reductase. | desulfovibrio vulgaris rubredoxin, which contains a single [fe(scys)4] site, is shown to be a catalytically competent electron donor to two enzymes from the same organism, namely, rubrerythrin and two-iron superoxide reductase (a.k.a. rubredoxin oxidoreductase or desulfoferrodoxin). these two enzymes have been implicated in catalytic reduction of hydrogen peroxide and superoxide, respectively, during periods of oxidative stress in d. vulgaris, but their proximal electron donors had not been char ... | 2001 | 11566030 |
| [method-performance studies of notified analytical method for fenbutatin oxide and cyhexatin]. | method-performance studies were conducted for the notified revised analytical method of fenbutatin oxide (fbto) and cyhexatin (cht). fbto and cht spiked into rice, soybeans, spinach, orange, tea powder and tea extract at the level of 0.5 microgram/g for fbto and 0.1 microgram/g for cht were analyzed in replicate in 6 laboratories. means recoveries of fbto were 85.2-96.5% and those of cht were 83.5-89.2% except from soybeans (46.5%). repeatability relative standard deviation values of fbto and ch ... | 2001 | 11577396 |
| the third naturally occurring attractant toward zoospores of phytopathogenic aphanomyces cochlioides from the spinacia oleracea host plant. | a bioassay-guided survey of spinach leaf constituents resulted in 5,4'-dihydroxy-3,3'-dimethoxy-6,7-methylenedioxyflavone being identified as the third naturally-occurring attractant in the host plant toward the zoospores of its pathogen, aphanomyces cochlioides. the isolate showed attracting activity around chromosorb w aw particles (60-80 mesh) coated with a 10(-5) m solution in a zoospore suspension. however, this activity was 1/100-1/1000 less than that of cochliophilin a, an attractant in t ... | 2001 | 11577714 |
| electron transport inhibitor in cyperus javanicus. | the natural quinone, hydroxydietrichequinone (3-heptadec-8-enyl-2-hydroxy-5-methoxy-[1,4]benzoquinone) is a secondary metabolite of cyperus javanicus. we found that this quinone inhibited both mitochondrial respiration and photosynthesis in their electron transportation systems. the quinone was found to have a mode of action against the ubiquinone reductase site from the results of different electron donor experiments on intact mitochondria from rat liver. the electron transport system, photosys ... | 2001 | 11577726 |
| determination of folates in foods by high-performance liquid chromatography with fluorescence detection after precolumn conversion to 5-methyltetrahydrofolates. | a liquid chromatographic-fluorimetric determination of folates in foodstuffs including their extraction, without or with deconjugation, chemical conversion to 5-ch3-h4pteglu(n) and purification of the extract by affinity chromatography is reported. the conversion enables the analysis of total folates and also of the contents of the different mono- and polyglutamate forms of the folates. the method has a satisfactory day-to-day repeatability (never,more than 10%) and a very low detection limit (0 ... | 2001 | 11589473 |
| substrate water exchange in photosystem ii depends on the peripheral proteins. | the (18)o exchange rates for the substrate water bound in the s(3) state were determined in different photosystem ii sample types using time-resolved mass spectrometry. the samples included thylakoid membranes, salt-washed triton x-100-prepared membrane fragments, and purified core complexes from spinach and cyanobacteria. for each sample type, two kinetically distinct isotopic exchange rates could be resolved, indicating that the biphasic exchange behavior for the substrate water is inherent to ... | 2001 | 11595731 |
| implications of secondary structure prediction and amino acid sequence comparison of class i and class ii phosphoribosyl diphosphate synthases on catalysis, regulation, and quaternary structure. | spinach 5-phospho-d-ribosyl alpha-1-diphosphate (prpp) synthase isozyme 4 was synthesized in escherichia coli and purified to near homogeneity. the activity of the enzyme is independent of p(i); it is inhibited by adp in a competitive manner, indicating a lack of an allosteric site; and it accepts atp, datp, gtp, ctp, and utp as diphosphoryl donors. all of these properties are characteristic for class ii prpp synthases. k(m) values for atp and ribose 5-phosphate are 77 and 48 microm, respectivel ... | 2001 | 11604537 |
| desaturation of oleoyl groups in envelope membranes from spinach chloroplasts. | envelope membranes isolated from chloroplasts of spinach (spinacia oleracea) desaturate oleoyl groups in monogalactosyl diacylglycerol to linoleoyl groups. the desaturation requires nadph in combination with ferredoxin and is not restricted to monogalactosyl diacylglycerol, since it is also observed in biosynthetic intermediates as, for example, in phosphatidic acid. this indicates a certain degree of unspecificity of the oleate desaturase in isolated envelope membranes. lipid desaturation is an ... | 1990 | 11607123 |
| gibberellin a1 is required for stem elongation in spinach. | the effects of the growth retardants 2'-isopropyl-4'-(trimethylammonium chloride)-5'-methylphenyl piperidine-1-carboxylate (amo-1618) and calcium 3,5-dioxo-4-propionylcyclohexanecarboxylate (bx-112) on stem elongation were investigated in the rosette plant spinach (spinacia oleracea l.) under long-day (ld) conditions. stem growth induced by a ld treatment was prevented by both retardants. the inhibition caused by amo-1618 was reversed by gibberellin a1 (ga1) and ga20, whereas the effects of bx-1 ... | 1993 | 11607418 |
| relationship between photosynthetic electron transport and ph gradient across the thylakoid membrane in intact leaves. | under conditions (0.2% co2; 1% o2) that allow high rates of photosynthesis, chlorophyll fluorescence was measured simultaneously with carbon assimilation at various light intensities in spinach (spinacia oleracea) leaves. using a stoichiometry of 3 atp/co2 and the known relationship between atp synthesis rate and driving force (delta ph), we calculated the light-dependent ph gradient (delta ph) across the thylakoid membrane in intact leaves. these delta ph values were correlated with the photoch ... | 1995 | 11607620 |
| isolation of a choline monooxygenase cdna clone from amaranthus tricolor and its expressions under stress conditions. | plants synthesize the osmoprotectant glycine betaine (gb) via choline-->betaine aldehyde-->glycine betaine[1]. two enzymes are involved in the pathway, choline monooxygenase (cmo) and betaine aldehyde dehydrogenase (badh). a full length cmo cdna (1,643bp) was cloned from amaranthus tricolor. the open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with cmos in spinacia oleracea l. and beta vulgaris l. dna gel blot analysis indicated the presence of one copy of cmo g ... | 2001 | 11642403 |
| voltammetry of plastocyanin at a graphite electrode: effects of structure, charge, and electrolyte. | comparative voltammetric studies on anabaena variabilis plastocyanin (positively charged at neutral ph) and spinach and poplar plastocyanins (negatively charged at neutral ph) have been undertaken at an edge-plane graphite electrode as a function of ionic strength, ph, and mg(2+) concentration at 3 degrees c. the aim was to provide a more detailed understanding of the influence of the electrode-protein (solution) interfacial characteristics, as well as the variation of the formal potential with ... | 1996 | 11666900 |
| the assembly of the psad subunit into the membranal photosystem i complex occurs via an exchange mechanism. | psad is a peripheral stromal-facing subunit of photosystem i (psi), a multisubunit complex of the thylakoid membranes. psad plays a major role in both the function and assembly of psi. past studies with radiolabeled psad indicated that psad is able to assemble in vitro specifically into the psi complex. to unravel the mechanism by which this assembly takes place, the following steps were taken. (i) mature psad of spinach and psad of the prokaryotic caynobacterium mastigocladus laminosus, both be ... | 2001 | 11669611 |
| formation, properties, and characterization of a fully reduced fe(ii)fe(ii) form of spinach (and parsley) [2fe-2s] ferredoxin with the macrocyclic complex [cr(15-anen(4))(h(2)o)(2)](2+) as reductant. | reduction of spinach and parsley ferredoxin fdi in the fe(iii)fe(iii) state with the 1,4,8,12-tetraazacyclopentadecane complex [cr(15-anen(4))(h(2)o)(2)](2+), here written as cr(ii)l, provides the first evidence for two 1-equiv steps yielding an fe(ii)fe(ii) product. rate constants (25 degrees c) for spinach fdi are 2760 and 660 m(-)(1) s(-)(1), respectively, at ph 7.5, i = 0.100 m (nacl). an important observation is that the cr(iii)l generated in the first step remains attached to the fe(ii)fe( ... | 1997 | 11669717 |
| phytotoxic naphthopyranone derivatives from the coprophilous fungus guanomyces polythrix. | reinvestigation of the fermentation broth and mycelium of the coprophilous fungus guanomyces polythrix, grown in static conditions, led to the isolation of several phytotoxic compounds, including two new naphthopyranone derivatives, namely (2s, 3r)-5-hydroxy-6,8-dimethoxy-2,3-dimethyl-2,3-dihydro-4h-naphtho[2,3-b]-pyran-4-one and (2s, 3r)-5-hydroxy-6,8,10-trimethoxy-2,3-dimethyl-2,3-dihydro-4h-naphtho[2,3-b]-pyran-4-one. the structures of the new compounds were established by spectral and chirop ... | 2001 | 11672740 |
| phosphorylation of synthetic peptides by a cdpk and plant snf1-related protein kinase. influence of proline and basic amino acid residues at selected positions. | spinach (spinacia oleracea l.) leaf sucrose-phosphate synthase (sps) can be inactivated by phosphorylation of ser-158 by calmodulin-like domain protein kinases (cdpks) or snf1-related protein kinases (snrk1) in vitro. while the phosphorylation site sequence is relatively conserved, most of the deduced sequences of sps from dicot species surrounding the ser-158 regulatory phosphorylation site contain a pro residue at p-4 (where p is the phosphorylated ser); spinach is the exception and contains a ... | 2001 | 11673623 |
| crystallization and preliminary x-ray diffraction analysis of glutathione-dependent dehydroascorbate reductase from spinach chloroplasts. | glutathione-dependent dehydroascorbate reductase (gsh-dhar) catalyzes the reduction of dehydroascorbate to ascorbate using reduced glutathione as the electron donor. gsh-dhar from spinach chloroplasts produced in escherichia coli was crystallized by the hanging-drop vapour-diffusion method. the crystals were monoclinic, space group c2, with unit-cell parameters a = 98.25, b = 39.96, c = 106.86 a, beta = 110.46 degrees. the asymmetric unit contained two molecules, giving a crystal volume per enzy ... | 2001 | 11679758 |
| proteome map of the chloroplast lumen of arabidopsis thaliana. | the thylakoid membrane of the chloroplast is the center of oxygenic photosynthesis. to better understand the function of the luminal compartment within the thylakoid network, we have carried out a systematic characterization of the luminal thylakoid proteins from the model organism arabidopsis thaliana. our data show that the thylakoid lumen has its own specific proteome, of which 36 proteins were identified. besides a large group of peptidyl-prolyl cis-trans isomerases and proteases, a family o ... | 2002 | 11719511 |
| supermolecular organization of photosystem ii and its associated light-harvesting antenna in arabidopsis thaliana. | the organization of arabidopsis thaliana photosystem ii (psii) and its associated light-harvesting antenna (lhcii) was studied in isolated psii-lhcii supercomplexes and native membrane-bound crystals by transmission electron microscopy and image analysis. over 4000 single-particle projections of psii-lhcii supercomplexes were analyzed. in comparison to spinach supercomplexes [boekema, e.j., van roon, h., van breemen, j.f.l. & dekker, j.p. (1999) eur. j. biochem. 266, 444-452] some striking diffe ... | 2001 | 11732995 |
| carotenoids affect proliferation of human prostate cancer cells. | we investigated whether various carotenoids present in foodstuffs were potentially involved in cancer-preventing action on human prostate cancer. the effects of 15 kinds of carotenoids on the viability of three lines of human prostate cancer cells, pc-3, du 145 and lncap, were evaluated. when the prostate cancer cells were cultured in a carotenoid-supplemented medium for 72 h at 20 micromol/l, 5,6-monoepoxy carotenoids, namely, neoxanthin from spinach and fucoxanthin from brown algae, significan ... | 2001 | 11739884 |
| regulation of nitric oxide (no) production by plant nitrate reductase in vivo and in vitro. | no (nitric oxide) production from sunflower plants (helianthus annuus l.), detached spinach leaves (spinacia oleracea l.), desalted spinach leaf extracts or commercial maize (zea mays l.) leaf nitrate reductase (nr, ec 1.6.6.1) was continuously followed as no emission into the gas phase by chemiluminescence detection, and its response to post-translational nr modulation was examined in vitro and in vivo. nr (purified or in crude extracts) in vitro produced no at saturating nadh and nitrite conce ... | 2002 | 11741046 |
| rubiscolin, a delta selective opioid peptide derived from plant rubisco. | we found that the sequences ypldl and ypldlf in the large subunit of spinach d-ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) met the structure yp-aliphatic amino acid which might have opioid activity. we then synthesized these peptides to test their opioid activity. the ic(50) of these peptides in mouse vas deferens assay were 51.0 microm and 24.4 microm, respectively, and those in delta receptor binding assay using [(3)h]deltorphin ii as radioligand were 2.09 microm and 0.93 microm, ... | 2001 | 11741591 |
| thioredoxin-mediated reductive activation of a protein kinase for the regulatory phosphorylation of c4-form phosphoenolpyruvate carboxylase from maize. | the activity of phosphoenolpyruvate carboxylase (pepc, ec4.1.1.31) for the c4 photosynthesis is known to be regulated mainly in response to light/dark transitions through reversible phosphorylation by a specific protein kinase (pk). pepc-pk with an m(r) of 30 kda was purified about 1.4 million-fold to homogeneity from maize leaves and characterized. the purified pepc-pk was readily inactivated under mild oxidative conditions, but the activity could be recovered by dithiothreitol (dtt). the recov ... | 2001 | 11773521 |
| 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 |
| decreased absorption and retention rates of magnesium in the rats fed on spinach-supplemented diets: possible explanations. | we studied the bioavailability of magnesium (mg) in spinach after boiling with distilled water, using mg-deficient growing male rats. the rats were fed a semipurified diet (mg:0.063 per cent (w/w)) for 3 days. then a mg-deficient diet (mg:0.001 per cent (w/w)) for 5 days. they were then divided randomly into 7 groups of 6 rats each, and fed the semipurified diet (mg: 0.063, 0.045 or 0.027 per cent (w/w)), or the spinach-supplemented diet (10 per cent (w/w) dried and powdered spinach after boilin ... | 2001 | 11794632 |
| dietary factors and gastric cancer in korea: a case-control study. | to assess gastric cancer (gc) risk in relation to dietary intake in korea, a case-control study was performed. trained dietitians interviewed 136 patients diagnosed with gc, and the same number of controls were selected by matching sex, age and hospital. a significant decrease in gc risk was observed with increased intake of baiechu kimchi (prepared with salted chinese cabbage and red pepper, etc.), baiechu kimchi-stew, garlic, mushroom and soybean milk. on the contrary, a significant increase i ... | 2002 | 11802218 |
| 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 |
| crystal structure of the non-regulatory a(4 )isoform of spinach chloroplast glyceraldehyde-3-phosphate dehydrogenase complexed with nadp. | here, we report the first crystal structure of a photosynthetic glyceraldehyde-3-phosphate dehydrogenase (gapdh) complexed with nadp. the enzyme, purified from spinach chloroplasts, is constituted of a single type of subunit (a) arranged in homotetramers. it shows non-regulated nadp-dependent and nad-dependent activities, with a preference for nadp. the structure has been solved to 3.0 a resolution by molecular replacement. the crystals belong to space group c222 with three monomers in the asymm ... | 2001 | 11846565 |
| 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 |
| [a cohort study on the relationship between vegetable intake and risks of lung cancer in the tin corporation (ytc) miners in yunnan]. | to understand the relationship between vegetable intake and risk of lung cancer in the tin corporation (ytc) miners in yunnan. | 2000 | 11860786 |
| enhanced susceptibility of photosynthesis to low-temperature photoinhibition due to interruption of chill-induced increase of s-adenosylmethionine decarboxylase activity in leaves of spinach (spinacia oleracea l.). | the possible involvement of polyamines in the chilling tolerance of spinach (spinacia oleracea l.) was investigated focusing on photosynthesis. during chilling at 8/5c (day/night) for 6 d, s-adenosylmethionine decarboxylase (samdc) activity increased significantly in leaves in parallel with the increase in putrescine and spermidine (spd) content in leaves and chloroplasts. treatment of leaves with methylglyoxal-bis(guanylhydrazone) (mgbg), an samdc inhibitor, resulted in the deterioration of pla ... | 2002 | 11867699 |
| total antioxidant and ascorbic acid content of fresh fruits and vegetables: implications for dietary planning and food preservation. | epidemiological evidence links high intake of ascorbic acid (aa) and other antioxidant micronutrients to health promotion. it would be useful to know the overall, or 'total' antioxidant capacity of foods, to establish the contribution of aa to this, and to assess how this information may translate into dietary intakes to meet the new us daily reference intake for aa. in this study, the total antioxidant capacity, as the ferric reducing-antioxidant power (frap) value, and aa content of thirty-fou ... | 2002 | 11898770 |
| 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 |
| [vegetables rich in carotenoids on the vitamin a status of children]. | vitamin a (va) deficiency is still an important nutritional problem in our country. in order to determine whether plant carotenoids ingestion can improve va nutrition, a study by using yellow and dark green vegetables was conducted in two classes of a kindergarten for ten weeks in september through december in 1996. the va nutritional status was marginal to adequate among 41 children (5.3-6.6 year-old), and serum retinols in 39% of these children were below 0.30 mg/l. each child in class a was p ... | 1999 | 11938982 |
| the regulation of nitrate reductase activity from spinach spinacea oleracea l. leaves by thiol compounds in the presence of adenosine-5'-diphosphate. | 1971 | 11945970 | |
| reversible cyanide inhibition of spinach (spinacea oleracea l.) nitrate reductase and non-exchangeability in vitro of protein bound molybdenum and tungsten. | 1971 | 11946072 | |
| pyruvate,orthophosphate dikinase in leaves and chloroplasts of c(3) plants undergoes light-/dark-induced reversible phosphorylation. | pyruvate,orthophosphate (pi) dikinase (ppdk) is best recognized as a chloroplastic c(4) cycle enzyme. as one of the key regulatory foci for controlling flux through this photosynthetic pathway, it is strictly and reversibly regulated by light. this light/dark modulation is mediated by reversible phosphorylation of a conserved threonine residue in the active-site domain by the ppdk regulatory protein (rp), a bifunctional protein kinase/phosphatase. ppdk is also present in c(3) plants, although it ... | 2002 | 11950985 |
| 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 |
| accumulation of a 31-kda glycoprotein in association with the expression of embryogenic potential by spinach callus in culture. | calli grown from segments of spinach (spinacia oleracea l.) root in the presence of gibberellic acid (ga3) plus auxin, differentiated to yield somatic embryos after transfer to a medium without growth regulators, while calli formed in the absence of ga3 failed to generate any embryos. we extracted proteins from the two types of callus and analysed them by polyacrylamide gel electrophoresis. compared with the proteins from calli formed on medium that contained only naphthaleneacetic acid (naa) as ... | 2002 | 11982941 |
| detection and characterization of gtp-binding proteins in the chloroplast envelope of spinach (spinacia oleracea). | proteins binding guanosine triphosphate (gtp) have emerged as important regulators in several cellular processes in plants. to investigate any role of such proteins in chloroplast functions, we subjected envelope, stroma and thylakoid fractions isolated from spinach chloroplasts to two different gtp-binding assays. with both methods, we detected gtp-specific binding only in the envelope fraction. two chloroplast envelope proteins with the apparent molecular weights of 30.5 and 33.5 kda, respecti ... | 2002 | 11982945 |
| patterns of methyl and o-acetyl esterification in spinach pectins: new complexity. | driselase-digestion of cell walls from suspension-cultures of spinach (spinacia oleracea l.), followed by anion-exchange chromatography, gel-permeation chromatography, preparative paper chromatography and preparative paper electrophoresis, yielded ten uronic acid-containing products in addition to free galacturonic acid (gala). these included 4-o-methylglucuronic acid, alpha-l-rhamnopyranosyl-(1-->4)-d-glucuronic acid and several oligosaccharides containing gala residues. the structures were una ... | 2002 | 11985854 |
| light regulation of gibberellin biosynthesis and mode of action. | some phenotypic effects produced in plants by light are very similar to those induced by hormones. in this review, the light-gibberellin (ga) interaction in germination, de-etiolation, stem growth, and tuber formation (process regulated by gas) are discussed. germination of lettuce and arabidopsis seeds depends on red irradiation (r), which enhances the expression of ga 3-oxidase genes (ga3ox) and leads to an increase in active ga content. de-etiolation of pea seedling alters the expression of g ... | 2001 | 11986761 |
| 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 |
| analysis of antioxidant activities of common vegetables employing oxygen radical absorbance capacity (orac) and ferric reducing antioxidant power (frap) assays: a comparative study. | a total of 927 freeze-dried vegetable samples, including 111 white cabbages, 59 carrots, 51 snap beans, 57 cauliflower, 33 white onions, 48 purple onions, 130 broccoli, 169 tomatoes, 25 beets, 88 peas, 88 spinach, 18 red peppers, and 50 green peppers, were analyzed using the oxygen radical absorption capacity (orac) and ferric reducing antioxidant capacity (frap) methods. the data show that the orac and frap values of vegetable are not only dependent on species, but also highly dependent on geog ... | 2002 | 12009973 |
| 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 |
| action of an algicide from a cyanobacterium, oscillatoria laetevirens, on photosystem ii. | oscillatoria laetevirens produces an algicide, named oscillatorin (os), which inhibits growth of higher plants. effect of purified oscillatorin and some 'urea-triazine type' herbicides was studied on photosystem ii activity and composition of pigment protein complex in spinach thylakoid membrane. for oscillatorin the i50 at 10 microg chlorophyll concentration, inhibitor constant (ki), specific binding sites and hill coefficient were calculated to be 1.45, 0.15, 2.3 and 0.2 microm respectively. m ... | 2001 | 12018523 |
| increased tolerance to thermal inactivation of oxygen evolution in spinach photosystem ii membranes by substitution of the extrinsic 33-kda protein by its homologue from a thermophilic cyanobacterium. | photosynthetic oxygen evolution is an extremely heat-sensitive process and incubation of spinach photosystem ii (psii) membranes at 40 degrees c for only several minutes leads to its complete inactivation. substitution experiments of the spinach 33-kda manganese stabilizing protein by a homologue protein, isolated either from the thermophilic cyanobacterium phormidium laminosum, or from escherichia coli as a recombinant thermophilic cyanobacterial protein, showed a significant increase in tolera ... | 2002 | 12034468 |
| characterization of the oxygen tolerance of a hydrogenase linked to a carbon monoxide oxidation pathway in rubrivivax gelatinosus. | a hydrogenase linked to the carbon monoxide oxidation pathway in rubrivivax gelatinosus displays tolerance to o2. when either whole-cell or membrane-free partially purified hydrogenase was stirred in full air (21% o2, 79% n2), its h2 evolution activity exhibited a half-life of 20 or 6 h, respectively, as determined by an anaerobic assay using reduced methyl viologen. when the partially purified hydrogenase was stirred in an atmosphere containing either 3.3 or 13% o2 for 15 min and evaluated by a ... | 2002 | 12039713 |
| synthesis of a novel class of polyhydroxyalkanoates in arabidopsis peroxisomes, and their use in monitoring short-chain-length intermediates of beta-oxidation. | the poly[(r)-3-hydroxyalkanoate] (pha) synthase gene (phac(ac)) of aeromonas caviae fa440 was modified by adding a peroxisome targeting signal encoding the last 10 amino acids at the carboxyl-terminal of spinach glycolate oxidase. the modified gene was introduced into arabidopsis thaliana plants by agrobacterium-mediated transformation. the transgenic arabidopsis plant expressed the introduced gene and its protein, and it accumulated pha in its tissues. gas chromatography-mass spectrometry analy ... | 2002 | 12040103 |
| synthesis and bacterial expression of a gene encoding the heme domain of assimilatory nitrate reductase. | assimilatory nadh:nitrate reductase (ec 1.6.6.1), a complex mo-pterin-, cytochrome b(557)-, and fad-containing protein, catalyzes the regulated and rate-limiting step in the utilization of inorganic nitrogen by higher plants. a codon-optimized gene has been synthesized for expression of the central cytochrome b(557)-containing fragment, corresponding to residues a542-e658, of spinach assimilatory nitrate reductase. while expression of the full-length synthetic gene in escherichia coli did not re ... | 2002 | 12051681 |
| effects of food materials on removal of allium-specific volatile sulfur compounds. | effects of food materials were investigated on removal of several kinds of thiols, sulfides, and disulfides, which arise from vegetables of allium species during food preparation and eating. methanethiol, propanethiol, and 2-propenethiol were captured by raw foods such as fruits, vegetables, and mushrooms or a mixture of their acetone powders and phenolic compounds. the odor of diallyl disulfide was remarkably reduced by kiwi fruit, spinach, cutting lettuce, parsley, basil, mushrooms, and, parti ... | 2002 | 12059171 |
| the inhibition of ammonium uptake in excised birch (betula pendula) roots by batatasin-iii. | in northern sweden, plants growing in association with the clonal dwarf shrub empetrum hermaphroditum usually exhibit limited growth and are n-depleted. previous studies suggest that this negative effect by e. hermaphroditum may be explained, at least in part, by the release of phenolic compounds, particularly the dihydrostilbene, batatasin-iii from foliage to soil. in the present work, we investigated whether batatasin-iii has the potential to interfere with nh4+ uptake in birch (betula pendula ... | 2001 | 12060282 |
| characterization of substrate specificity of plant fata and fatb acyl-acp thioesterases. | the specificity of plant acyl-acyl carrier protein (acp) thioesterases is the major determinant of the chain length and level of saturated fatty acids found in most plant tissues. although these enzymes have been previously characterized from a number of sources, information on kinetic parameters for a wide range of substrates with cloned enzymes is lacking. in the present study the substrate specificity of recombinant fata thioesterase isoforms from arabidopsis (atfata) and coriander (csfata) a ... | 2002 | 12061798 |
| molecular and biochemical analysis of serine acetyltransferase and cysteine synthase towards sulfur metabolic engineering in plants. | serine acetyltransferase (satase) and cysteine synthase (o-acetylserine (thiol)-lyase) (csase) are committed in the final step of cysteine biosynthesis. six cdna clones encoding satase have been isolated from several plants, e.g. watermelon, spinach, chinese chive and arabidopsis thaliana. feedback-inhibition pattern and subcellular localization of plant satases were evaluated. two types of satase that differ in their sensitivity to the feedback inhibition by l-cysteine were found in plants. in ... | 2002 | 12083067 |
| phytotoxic compounds from prionosciadium watsoni. | bioassay-guided fractionation of a phytotoxic extract of prionosciadium watsoni led to the isolation of three new pyranocoumarins and two pyranochromones. the new compounds were characterized as propionic acid (9r,10r)-9-acetoxy-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (1), isobutyric acid (9r,10r)-9-hydroxy-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (2), isobutyric acid (9r)-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b'] ... | 2002 | 12088423 |
| unique fluorescence properties of a cyanobacterium gloeobacter violaceus pcc 7421: reasons for absence of the long-wavelength psi chl a fluorescence at -196 degrees c. | we investigated the reason for the absence of the long-wavelength psi chl a fluorescence at -196 degrees c in the cyanobacterium gloeobacter violaceus using two methods: p-nitrothiophenol (p-ntp) treatment and time-resolved fluorescence spectra. the p-ntp treatment showed that psii chl a fluorescence was specifically affected in a manner similar to that for synechocystis sp. pcc 6803 and spinach chloroplasts, although there were no components modified by the p-ntp treatment, indicating an absenc ... | 2002 | 12091711 |
| kinetic characteristics of chloroplast glucose transport. | influx of labelled d-glucose into isolated spinach (spinacia oleracea l. cv. melody hybrid) chloroplasts was initially rapid followed by a period of slower influx. the stroma glucose concentration attained equilibrium rapidly with low external glucose concentrations and the two were linearly proportional. the period of slower influx resulted from conversion of glucose to acidic products that remained trapped in the chloroplast. as the external glucose concentration increased, the stroma glucose ... | 2002 | 12096097 |
| effect of domestic processing and cooking methods on total, hcl extractable iron and in vitro availability of iron in spinach and amaranth leaves. | spinach (spinacia oleracia) and amaranth (amaranthus tricolor) leaves were stored in polyethylene bags and without packing for 24 and 48 hours in a refrigerator at 5 degrees c and 30 degrees c in polyethylene bags. the fresh leaves were also dried (oven and sun), blanched (5, 10 and 15 min) and cooked in an open pan and a pressure cooker. the processed leaves were analysed for total iron, its availability and antinutrient content. the iron content of these leaves varied from 26.54 to 34.14 mg/10 ... | 2002 | 12102364 |
| eighteen-month-old fischer 344 rats fed a spinach-enriched diet show improved delay classical eyeblink conditioning and reduced expression of tumor necrosis factor alpha (tnfalpha ) and tnfbeta in the cerebellum. | diets high in antioxidant properties are known to reverse some deficits in neuronal and cognitive function that occur in aging animals. antioxidants are also known to reduce levels of proinflammatory factors in the cns. we report here that 6 weeks of a spinach-enriched diet ameliorates deficits in cerebellar-dependent delay classical eyeblink learning and reduces the proinflammatory cytokines tumor necrosis factor alpha (tnfalpha) and tnfbeta in the cerebelli of eyeblink-trained animals. eightee ... | 2002 | 12122042 |
| monoclonal anti-diuron antibodies prevent inhibition of photosynthesis by diuron. | two monoclonal anti-diuron antibodies were generated that bind to diuron with an extremely low equilibrium dissociation constant. the antibodies prevented and restored in vitro and in vivo the diuron-dependent inhibition of photosynthesis. in isolated thylakoids prepared from spinach leaves (spinacia oleracea l.) the diuron-inhibited hill reaction was reconstituted immediately after the addition of the monoclonal antibodies. the antibodies also restored the diuron-dependent inhibition of the pho ... | 2002 | 12123811 |
| mutational bisection of the mitochondrial dna stability and amino acid biosynthetic functions of ilv5p of budding yeast. | ilv5p is a bifunctional yeast mitochondrial enzyme required for branched chain amino acid biosynthesis and for the stability of mitochondrial dna (mtdna) and its parsing into nucleoids. the latter occurs when the general amino acid control (gac) pathway is activated. we have isolated ilv5 mutants that lack either the enzymatic (a(-)d(+)) or the mtdna stability function (a(+)d(-)) of the protein. the affected residues in these two mutant classes cluster differently when mapped to the 3-d structur ... | 2002 | 12136009 |
| transfer of the fungicide vinclozolin from treated to untreated plants via volatilization. | head lettuce plantlets (lactuca sativa l. var. capitata) were potted, treated with vinclozolin at the six-leaf stage according to application standards and allowed to dry for 24 h. the potted plantlets were then placed in either growth chambers with controlled temperature (20 and 25 degrees c, respectively) or in a greenhouse (approximately 12 degrees c), together with untreated spinach (spinacia oleracea l.) and standardized grass cultures (lolium multiflorum lam. ssp.) while the treated lettuc ... | 2002 | 12137060 |
| bacterial expression of the molybdenum domain of assimilatory nitrate reductase: production of both the functional molybdenum-containing domain and the nonfunctional tungsten analog. | assimilatory nadh:nitrate reductase (ec 1.6.6.1), a complex molybdenum-, cytochrome b(557)- and fad-containing protein, catalyzes the regulated and rate-limiting step in the utilization of inorganic nitrogen by higher plants. to facilitate structure/function studies of the individual molybdenum center, we have developed bacterial expression systems for the heterologous production of the 541 residue amino-terminal, molybdenum center-containing domain of spinach nitrate reductase either as a six-h ... | 2002 | 12139973 |
| in vitro reconstitution of the spinach chloroplast cytochrome b6 protein from a fusion protein expressed in escherichia coli. | we have developed a strategy for overproduction of spinach apocytochrome b6 as a fusion protein to maltose-binding protein (mbp) in escherichia coli, using the expression vector pmal-c2. the fusion protein was purified to virtual homogeneity by gel filtration chromatography and the method of insertion of hemes into fusion protein was elaborated. the ambient and low-temperature absorption spectra of the reconstituted cytochrome b6 were similar to those of cytochrome b6 spectra in isolated protein ... | 2002 | 12147358 |
| [cloning and expression of spinach glycolate oxidase in escherichia coli]. | the cdna coding spinach glycolate oxidase (go) was amplified by rt-pcr using the total 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 e. coli expression vector pbv220, pet-22b(+), ptig-trx and pthiohisc. sds-page analysis revealed that the recombinant e. coli bl21 (de3) (ptig-trx-go) and e. coli bl21 (de3) (pet-22b(+)-go) expressed the predicted 38 kd glycolate oxidase, and the enzyme activi ... | 2002 | 12148286 |
| identifying and characterizing plastidic 2-oxoglutarate/malate and dicarboxylate transporters in arabidopsis thaliana. | we characterized three arabidopsis genes, atpomt1, atpdct1 and atpdct2, localized on chromosome 5 and homologous to spinach chloroplastic 2-oxoglutarate/malate transporter (omt) gene. the yeast-expressed recombinant atpomt1 protein transported malate and 2-oxoglutarate but not glutamate. by contrast, the recombinant atpdct1 protein transported 2-oxoglutarate and glutamate at similar affinities in exchange for malate. these findings suggested that atpomt1 is omt and atpdct1 is a general dicarboxy ... | 2002 | 12154133 |
| supramolecular organization of photosystem i and light-harvesting complex i in chlamydomonas reinhardtii. | we report a structural characterization by electron microscopy and image analysis of a supramolecular complex consisting of photosystem i and light-harvesting complex i from the unicellular green alga chlamydomonas reinhardtii. the complex is a monomer, has longest dimensions of 21.3 and 18.2 nm in projection, and is significantly larger than the corresponding complex in spinach. comparison with photosystem i complexes from other organisms suggests that the complex contains about 14 light-harves ... | 2002 | 12163173 |
| expression in plants and immunogenicity of plant virus-based experimental rabies vaccine. | a new approach to the production and delivery of vaccine antigens is the use of engineered amino virus-based vectors. a chimeric peptide containing antigenic determinants from rabies virus glycoprotein (g protein) (amino acids 253-275) and nucleoprotein (n protein) (amino acids 404-418) was pcr-amplified and cloned as a translational fusion product with the alfalfa mosaic virus (almv) coat protein (cp). this recombinant cp was expressed in two plant virus-based expression systems. the first one ... | 2002 | 12163267 |
| new sources of dietary myosmine uptake from cereals, fruits, vegetables, and milk. | myosmine has been regarded as a specific tobacco alkaloid until investigations pointed out that nuts and nut products constitute a significant source of myosmine. in the present study it is shown that the occurrence of myosmine is widespread throughout a large number of plant families. using a method for extraction practicable for all examined foods, quantitative analysis through internal standard addition showed nanograms per gram amounts. positively tested edibles were staple foods such as mai ... | 2002 | 12166981 |
| regulation of sucrose and starch synthesis in wheat (triticum aestivum l.) leaves: role of fructose 2,6-bisphosphate. | fructose 2,6-bisphosphate (f26bp) is a competitive inhibitor of the cytosolic fructose 1,6-bisphosphatase (cytfbpase, ec 3.1.3.11). in spinach (spinacia oleracea l.) leaves it is a significant component of the complex regulatory network that co-ordinates rates of photosynthesis, sucrose synthesis and starch synthesis. however the role of f26bp has only been studied in plants that predominantly store starch in their leaves and its role in other species is not clear. this paper examines the signif ... | 2002 | 12172849 |
| identification of a cis element for tissue-specific alternative splicing of chloroplast ascorbate peroxidase pre-mrna in higher plants. | alternative splicing events in the 3'-terminal region of chloroplast ascorbate peroxidase (chlapx) pre-mrna in spinach and tobacco, which produced four types of mrna variants, one form (tapx-i) encoding thylakoid-bound apx (tapx) and three forms (sapx-i, -ii, and -iii) encoding stromal apx (sapx), were regulated in a tissue-specific manner. the ratio of the level of sapx mrnas (sapx-i, -ii, and -iii) to tapx-i mrna was close to 1 in leaf, whereas the ratio in root was greatly elevated due to an ... | 2002 | 12176976 |
| redox regulation of arabidopsis 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase. | the cdna for 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase of arabidopsis encodes a polypeptide with an amino-terminal signal sequence for plastid import. a cdna fragment encoding the processed form of the enzyme was expressed in escherichia coli. the resulting protein was purified to electrophoretic homogeneity. the enzyme requires mn(2+) and reduced thioredoxin (trx) for activity. spinach (spinacia oleracea) trx f has an apparent dissociation constant for the enzyme of about 0.2 microm. ... | 2002 | 12177500 |
| glu 103 gln site-directed mutation causes an alteration in physical properties of spinach betaine aldehyde dehydrogenase. | site-directed mutant of spinach betaine aldehyde dehydrogenase (badh) was obtained by replacing glu 103 with gln 103 and the resulting e 103 q mutant was expressed in escherichia coli. the mutant badh as compared to the wild-type badh was slightly more sensitive to inhibition by nacl but less sensitive to inhibition by (nh(4))(2)so(4). glycinebetaine (gb) activated the wild-type enzyme but not the mutant enzyme. stronger inhibition by choline was observed in the mutant enzyme than in the wild-ty ... | 2002 | 12186739 |
| gliadin is a good substrate of several transglutaminases: possible implication in the pathogenesis of coeliac disease. | deamidation of distinct glutamines in hla-dq2 restricted gliadin epitopes, considered critical in the pathogenesis of coeliac disease (cd), can be mediated by tissue transglutaminase (ttg). to elucidate the possible role of other transglutaminases in cd we investigated whether different mammalian, microbial and vegetable transglutaminases can use gliadin as substrate. | 2002 | 12190095 |
| functional characterization of choline monooxygenase, an enzyme for betaine synthesis in plants. | in plants, the first step in betaine synthesis was shown to be catalyzed by a novel rieske-type iron-sulfur enzyme, choline monooxygenase (cmo). although cmo so far has been found only in chenopodiaceae and amaranthaceae, the recent genome sequence suggests the presence of a cmo-like gene in arabidopsis, a betaine non-accumulating plant. here, we examined the functional properties of cmo expressed in escherichia coli, cyanobacterium, and arabidopsis thaliana. we found that e. coli cells in which ... | 2002 | 12192001 |
| accumulation of heavy metals in water spinach (ipomoea aquatica) cultivated in the bangkok region, thailand. | the aquatic plant water spinach (ipomoea aquatica), either wild or cultivated, is found throughout southeast asia and is a widely consumed vegetable in the region. many of the waters where i. aquatica grows serve as recipients for domestic and other types of wastewater. because these waters contain not only nutrients, but often also a wide variety of pollutants such as heavy metals from various human activities, many people risk intoxication. to estimate the accumulation of lead (pb), cadmium (c ... | 2002 | 12206434 |
| respiratory chain supercomplexes of mitochondria and bacteria. | respiratory chain complexes are fragments of larger structural and functional units, the respiratory chain supercomplexes or "respirasomes", which exist in bacterial and mitochondrial membranes. supercomplexes of mitochondria and bacteria contain complexes iii, iv, and complex i, with the notable exception of saccharomyces cerevisiae, which does not possess complex i. these supercomplexes often are stable to sonication but sensitive to most detergents except digitonin. in s. cerevisiae, a major ... | 2002 | 12206908 |
| crystal structure of oxyb, a cytochrome p450 implicated in an oxidative phenol coupling reaction during vancomycin biosynthesis. | gene-inactivation studies point to the involvement of oxyb in catalyzing the first oxidative phenol coupling reaction during glycopeptide antibiotic biosynthesis. the oxyb gene has been cloned and sequenced from the vancomycin producer amycolatopsis orientalis, and the hemoprotein has been produced in escherichia coli, crystallized, and its structure determined to 1.7-a resolution. oxyb gave uv-visible spectra characteristic of a p450-like hemoprotein in the low spin ferric state. after reductio ... | 2002 | 12207020 |
| enhanced employment of the xanthophyll cycle and thermal energy dissipation in spinach exposed to high light and n stress. | the involvement of the xanthophyll cycle in photoprotection of n-deficient spinach (spinacia oleracea l. cv nobel) was investigated. spinach plants were fertilized with 14 mm nitrate (control, high n) versus 0.5 mm (low n) fertilizer, and grown under both high- and low-light conditions. plants were characterized from measurements of photosynthetic oxygen exchange and chlorophyll fluorescence, as well as carotenoid and cholorophyll analysis. compared with the high-n plants, the low-n plants showe ... | 1997 | 12223645 |
| functional consequences of deletions of the n terminus of the [epsilon] subunit of the chloroplast atp synthase. | the [epsilon] subunit of the chloroplast atp synthase functions in part to prevent wasteful atp hydrolysis by the enzyme. in addition, [epsilon] together with the remainder of the catalytic portion of the synthase (cf1) is required to block the nonproductive leak of protons through the membrane-embedded component of the synthase (cfo). mutant [epsilon] subunits of the spinach (spinacia oleracea) chloroplast atp synthase that lack 5, 11, or 20 amino acids from their n termini ([epsilon]-[delta]5n ... | 1997 | 12223668 |
| the two forms of ribulose-1,5-bisphosphate carboxylase/oxygenase activase differ in sensitivity to elevated temperature. | ribulose-1,5-bisphosphate carboxylase/oxygenase activase often consists of two polypeptides that arise from alternative splicing of pre-mrna. in this study recombinant versions of the spinach (spinacea oleracea l.) 45- and 41-kd forms of activase were analyzed for their response to temperature. the temperature optimum for atp hydrolysis by the 45-kd form was 45[deg]c, approximately 13[deg]c higher than the 41-kd form. when the two forms were mixed, the temperature response of the hybrid enzyme w ... | 1997 | 12223718 |
| a plant chloroplast glutamyl proteinase. | a glutamyl proteinase was partially purified from percoll gradient-purified spinach (spinacia oleracea) chloroplast preparations and appeared to be predominantly localized in the chloroplast stroma. the enzyme degraded casein, but of the 11 synthetic endopeptidase substrates tested, only benzyloxycarbonyl-leucine-leucine-glutamic acid-[beta]-napthylamide was hydrolyzed at measurable rates. in addition, the enzyme cleaved the oxidized [beta]-chain of insulin after a glutamic acid residue. there w ... | 1997 | 12223739 |