Publications

phosphate sequestration by glycerol and its effects on photosynthetic carbon assimilation by leaves.	glycerol induced a limitation on photosynthetic carbon assimilation by phosphate when supplied to leaves of barley (hordeum vulgare l.) and spinach (spinacia oleracea l.). this limitation by phosphate was evidenced by (i) reversibility of the inhibition of photosynthesis by glycerol by feeding orthophosphate (ii) a decrease in light-saturated rates of photosynthesis and saturation at a lower irradiance, (iii) the promotion of oscillations in photosynthetic co2 assimilation and in chlorophyll flu ...	1988	24220742
import of peroxisomal hydroxypyruvate reductase into glyoxysomes.	a new procedure was used to purify the peroxisomal matrix enzyme hydroxypyruvate reductase (hpr) from green leaves of pumpkin (cucurbita pepo l.) and spinach (spinacia oleracea l.). monospecific antibodies were prepared against this enzyme in rabbits. immunoprecipitation of hpr from watermelon (citrullus vulgaris schrad.) yielded a single protein with a subunit molecular weight of 45 kda. immunohistochemical labeling of hpr was found exclusively in watermelon microbodies. isolated polyadenylated ...	1988	24220768
role of plastidial acyl-acyl carrier protein: glycerol 3-phosphate acyltransferase and acyl-acyl carrier protein hydrolase in channelling the acyl flux through the prokaryotic and eukaryotic pathway.	in order to investigate whether the relative activities of the plastidial acyl-acyl carrier protein (acp):glycerol 3-phosphate acyltransferase (ec 2.3.1.15) and acyl-acp hydrolase play a role in controlling the acyl flux through the prokaryotic and eukaryotic pathway, we determined these enzymic activities in stroma fractions from 16:3- and 18:3-plants using glycerol 3-phosphate and labelled acyl-acp as substrates. several factors were examined which might influence the activities within plastid ...	1988	24220947
chloroplast dna evolution in potato (solanum tuberosum l.).	a deletion specific to chloroplast (ct) dna of potato (solanum tuberosum ssp. tuberosum) was determined by comparative sequence analysis. the deletion was 241 bp in size, and was not flanked by direct repeats. five small, open reading frames were found in the corresponding regions of ctdnas from wild potato (s. tuberosum ssp. andigena) and tomato (lycopersicon esculentum). comparison of the sequences of 1.35-kbp haeiii ctdna fragments from potato, tomato, and tobacco (nicotiana tabacum) revealed ...	1991	24221153
coarse control of sucrose-phosphate synthase in leaves: alterations of the kinetic properties in response to the rate of photosynthesis and the accumulation of sucrose.	it has been investigated whether diurnal rhythms of sucrose-phosphate synthase (sps) are involved in controlling the rate of photosynthetic sucrose synthesis. extracts were prepared from spinach (spinacia oleracea l.) and barley (hordeum vulgare l.) leaves and assayed for enzyme activity. the activity of sps increased in parallel with a rising rate of photosynthesis, and was increased by feeding mannose and decreased by supplying inorganic phosphate. in leaf material where sucrose had accumulate ...	1988	24221478
fractional control of photosynthesis by the qb protein, the cytochrome f/b 6 complex and other components of the photosynthesic apparatus.	in order to obtain information on fractional control of photosynthesis by individual catalysts, catalytic activities in photosynthetic electron transport and carbon metabolism were modified by the addition of inhibitors, and the effect on photosynthetic flux was measured using chloroplasts of spinacia oleracea l. in thylakoids with coupled electron transport, light-limited electron flow to ferricyanide was largely controlled by the qb protein of the electron-transport chain. fractional control b ...	1988	24226408
effect of high light intensities on oxygen evolution and the light activation of nadp-malate dehydrogenase in intact spinach chloroplasts.	the factors limiting the photosynthetic carbon metabolism of intact spinach (spinacia oleracea l.) chloroplasts after a high-light pretreatment have been studied. photosynthetic co2 fixation was decreased and became more sensitive to the inhibitory effect of the cyclic-electron-flow inhibitor, antimycin a. depending on the extent of photoinhibition, changing the balance of linear to cyclic electron flow by adding oxaloacetate and antimycin a either did not relieve, or partially relieved the phot ...	1988	24226683
chalcone synthases from spinach (spinacia oleracea l.) : i. purification, peptide patterns, and immunological properties of different forms.	the two chalcone-synthase forms from leaves ofspinacia oleracea l. were purified to apparent homogeneity. antibodies were raised against both proteins in rabbits. the specificity of the antibodies was tested using immunotitration, immunoblotting, and immunoelectrophoresis techniques. the antibodies exhibited exclusive specificity for chalcone synthase and did not discriminate between the two antigens. the homodimeric chalcone synthases had the same subunit molecular weight but differed in their ...	1988	24226691
chalcone synthases from spinach (spinacia oleracea l.) : ii. immunofluorescence and immunogold localization.	the distribution of the two chalcone synthases in leaves ofspinacia oleracea l. was studied at both the tissue and the subcellular level using immunofluorescence and immunogold techniques. neither technique differentiated between the two enzyme forms. the chalcone synthases are located in the upper and the lower epidermis and to a minor extent in the subepidermal layers. traces of the two enzyme forms may be present in the residual mesophyll. this distribution is independent of leaf age. a simil ...	1988	24226692
non-photochemical quenching of chlorophyll a fluorescence in isolated chloroplasts under conditions of stressed photosynthesis.	non-photochemical quenching of chlorophyll a fluorescence after short-time light, heat and osmotic stress was investigated with intact chloroplasts from spinacia oleracea l. the proportions of non-photochemical fluorescence quenching (q n ) which are related (q e ) and unrelated (q i ) to the transthylakoid proton gradient (δph) were determined. light stress resulted in an increasing contribution of q ito total q n.the linear dependence of q. eand δph, as seen in controls, was maintained. the me ...	1987	24227329
calcium binding by spinach stromal proteins.	calcium binding to spinach (spinacia oleracea l.) stromal proteins was examined by dual-wavelength spectrophotometry using the metallochromic indicator tetramethylmurexide. the data are consistent with the existence of at least two, probably independent, classes of binding sites. the total number of binding sites varied between 90-155 nmol·mg(-1) protein with "average" binding constants of 1.1-2.7·mm(-1). both mg(2+) and la(3+) inhibited calcium binding competitively, with "average" inhibitor co ...	1987	24227335
α-1,4-glucan phosphorylase forms from leaves of spinach (spinacia oleracea l.) : ii. peptide patterns and immunological properties. a comparison with other phosphorylase forms.	peptide patterns and immunological properties of the cytoplasmic and chloroplastic α-1,4-glucan phosphorylase (ec 2.4.1.1) from spinach leaves have been studied and were compared with those of phosphorylases from other sources. the two spinach leaf phosphorylases were immunologically different; a limited cross-reactivity was observed only at high antigen or antibody concentrations. peptide mapping of the two enzymes resulted in complex patterns composed of more than 20 fragments; but no peptide ...	1986	24232025
freezing of isolated thylakoid membranes in complex media : iii. differences in the pattern of inactivation of photosynthetic reactions.	chloroplast thylakoid membranes isolated from spinach leaves (spinacia oleracea l. cv. monatol) were subjected to a freeze-thaw treatment in a buffered medium containing 70 mm kcl, 30 mm nano3 and 20 mm k2so4 in different combinations. in the presence of the three predominant inorganic electrolytes, inactivation of photophosphorylation was mainly caused by a decrease in the capacity of the photosynthetic electron transport; release of proteins from the membranes was not manifest and light-induce ...	1986	24232033
characterization and properties of the spinach chloroplast transcriptionally active chromosome isolated at high ionic strength.	the transcriptionally active chromosome (tac) of spinach (spinacia oleracea l.) chloroplasts has been isolated at a high ionic strength, with low mechanical shearing, by glycerol gradient centrifugation. the properties of the tac differ from those previously reported for the tac isolated either from euglena chloroplasts or from spinach using a low-ionic-strength solubilization medium and gel filtration. the high-salt-isolated tac is homogenous in density but not in size and contains fewer weakly ...	1986	24232757
resolution of two molecular forms of sucrose-phosphate synthase from maize, soybean and spinach leaves.	two forms of sucrose-phosphate synthase (ec 2.4.1.14) were resolved from leaves of three species, maize (zea mays l. cv. pioneer 3184), soybean (glycine max (l.) merr., cv. ransom) and spinach (spinacia oleracea l. cv. resistoflay) by hydroxyapatite ultrogel chromatography, using a 75-mm (designated peak 1) and 250-mm (peak 2) k-phosphate discontinuous-gradient elution. rechromatography of the two forms showed that they were not readily interconvertible. the distribution of activity between the ...	1987	24233014
salt treatment induces frost hardiness in leaves and isolated thylakoids from spinach.	frost hardiness of spinach (spinacia oleracea l.) leaves was increased by high concentrations of nacl in the hydroponic culture medium. freezing damage was determined by measurement of slow chlorophyll fluorescence quenching after freezing of leaves. both the osmolality of the leaf sap and forst hardiness of the leaves were linearly correlated with the salt concentration in the hydroponic culture medium. freezing damage occurred, irrespective of the extent of frost hardening, when dehydration of ...	1986	24233734
simulation of in situ freezing damage of the photosynthetic apparatus by freezing in vitro of thylakoids suspended in complex media.	chloroplast thylakoid membranes were isolated from leaves of unhardened and cold-acclimated spinach (spinacia oleracea l.). for freezethaw treatment, the membranes were suspended in complex media composed to simulate the solute concentrations in the chloroplast stroma in the unhardened and hardened states of the leaves. in particular, high concentrations of amino acids were applied for simulating the hardened state. after frost treatment, photosynthetic activities and chlorophyll fluorescence pa ...	1986	24233737
stimulation of photosynthesis by 2% oxygen at low temperatures is restored by phosphate.	the effect of phosphate feeding on the influence of low (2%) oxygen on photosynthetic carbon assimilation has been investigated in leaf discs of spinach (spinacia oleracea l.) at 12°c. the following observations were made. first, after the transition from 20% o2 to 2% o2, the rate of co2 uptake was inhibited at co2 concentrations between about 250 and about 800 μl co2·l(-1). second, phosphate feeding stimulated the rate of co2 uptake in 20% o2 at higher concentrations of co2 (500-900 μl·l(-1)). ...	1986	24233739
the relationship between phosphate status and photosynthesis in leaves : effects on intracellular orthophosphate distribution, photosynthesis and assimilate partitioning.	photosynthesis, assimilate partitioning and intracellular distribution of orthophosphate (pi) in barly (hordeum vulgare l.) leaves were measured in plants grown with either 25, 1 or 0 mmol· 1(-1) nutrient phosphate supply. phosphate deficiency resulted in a significant decrease in the leaf pi, diminished rates of photosynthesis and a decrease in the sucrose/starch ratio in the leaves. changes in the cytoplasmic pi content were relatively small in comparison with the large variations in vacuolar ...	1986	24240306
the relationship between phosphate status and photosynthesis in leaves : reversibility of the effects of phosphate deficiency on photosynthesis.	spinach (spinacia oleracea l.) and barley (hordeum vulgare l.) were grown in hydroponic culture with varying levels of orthophosphate (pi). when leaves were fed with 20 mmol·l(-1) pi at low co2 concentrations, a temporary increase of co2 uptake was observed in pi-deficient leaves but not in those from plants grown at 1 mmol·l(-1) pi. at high concentrations of co2 (at 21% or 2% o2) the pi-induced stimulation of co2 uptake was pronounced in the pi-deficient leaves. the contents of phosphorylated m ...	1986	24240307
the influence of a decrease in irradiance on photosynthetic carbon assimilation in leaves of spinacia oleracea l.	when leaves of spinacia oleracea l. were subjected to a decrease from a saturating to a limiting irradiance, photosynthetic carbon assimilation exhibited a pronounced lag. this comprised a postlower-illumination co2 burst (vines et al. 1982, plant physiol. 70, 629-631) and a slow increase in the rate of carbon assimilation to the new lower steady-state rate. the latter phenomenon was distinguishable from the former because it was present in leaves when photorespiration was inhibited by high conc ...	1986	24240313
α-1,4-glucan phosphorylase forms from leaves of spinach (spinacia oleracea l.) i. in situ localization by indirect immunofluorescence.	antisera were raised against two forms of α-1,4-glucan phosphorylase (ec 2.4.1.1) which had been purified from leaves of spinacia oleracea l. immunoglobulin g preparations were isolated from the antisera, and their specificity was ensured by immunoplobulin g preparations were used for in situ localization of the two phosphorylase forms in spinach leaf thin sections by indirect immuno-fluorescence. both enzyme forms were present in the palisade and spongy parenchyma and in the guard cells, but th ...	1986	24240359
monoclonal antibodies to a higher-plant nitrate reductase: differential inhibition of enzyme activities.	a set of monoclonal antibodies has been raised against nadh-nitrate reductase (nr; ec 1.6.6.1) from spinach (spinacea oleracea l.) leaves. antibodies were screened by enzyme-linked immunosorbent assay and by their ability to inhibit various activities of the enzyme. the six monoclonals selected (afrc mac 74 to 79) are all gamma globulins; four (mac 74 to 77) inhibit all terminal donating activities (nadh-nr; flavin mononucleotide, reduced form (fmnh2)-nr; and methyl viologen, reduced form (mv)-n ...	1985	24240965
effect of temperature on the co2/o 2 specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase and the rate of respiration in the light : estimates from gas-exchange measurements on spinach.	responses of the rate of net co2 assimilation (a) to the intercellular partial pressure of co2 (p i ) were measured on intact spinach (spinacia oleracea l.) leaves at different irradiances. these responses were analysed to find the value of p i at which the rate of photosynthetic co2 uptake equalled that of photorespiratory co2 evolution. at this co2 partial pressure (denoted г), net rate of co2 assimilation was negative, indicating that there was non-photorespiratory co2 evolution in the light. ...	1985	24241146
metabolite levels in the stroma of spinach chloroplasts exposed to osmotic stress: effects of the ph of the medium and exogenous dihydroxyacetone phosphate.	the levels of stromal photosynthetic intermediates were measured in isolated intact spinach (spinacia oleracea l.) chloroplasts exposed to reduced osmotic potentials. stressed chloroplasts showed slower rates of metabolite accumulation upon illumination than controls. relative to other metabolites sedoheptulose-1,7-bisphosphate (sbp) and fructose-1,6-bisphosphate (fbp) accumulated in the stroma in the stressed treatments. under these conditions 3-phosphoglycerate (3-pga) efflux to the medium was ...	1985	24241148
photoinhibition of photosynthesis under anaerobic conditions studied with leaves and chloroplasts of spinacia oleracea l.	the role of oxygen in the photoinactivation of the photosynthetic apparatus of spinacia oleracea l. was investigated. moderate irradiation (1200 μmol photons m(-2)s(-1)) of spinach leaves in an atmosphere of pure nitrogen caused strong inhibition of subsequently measured net co2 assimilation, whereas considerably less photoinhibition was observed in the presence of low partial pressures (10-20 mbar) of o2. the decrease in activity caused by anaerobiosis in the light was not based on stomatal clo ...	1985	24241150
effects of temperature at constant air dew point on leaf carboxylation efficiency and co2 compensation point of different leaf types.	the effect of temperature on photosynthesis at constant water-vapor pressure in the air was investigated using two sclerophyll species, arbutus unedo and quercus suber, and one mesophytic species, spinacia oleracea. photosynthesis and transpiration were measured over a range of temperatures, 20-39° c. the external concentration of co2 was varied from 340 μbar to near co2 compensation. the initial slope (carboxylation efficiency, ce) of the photosynthetic response to intercellular co2 concentrati ...	1985	24241315
characterization of calcium fluxes across the envelope of intact spinach chloroplasts.	calcium fluxes across the envelope of intact spinach chloroplasts (spinacia oleracea l.) in the light and in the dark were investigated using the metallochromic indicator arsenazo iii. light induces ca(2+) influx into chloroplasts. the action spectrum of light-induced ca(2+) influx and the inhibitory effect of 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (dcmu) indicate an involement of photosynthetic electron transport in this process. the driving force for light-induced ca(2+) influx is most like ...	1985	24241617
initiation and characterization of a cotton (gossypium hirsutum l.) photoautotrophic cell suspension culture.	a heterotrophic cotton (gossypium hirsutum l. cv. stoneville 825) cell suspension culture was adapted to grow photoautotrophically. after two years in continuous photoautotrophic culture at 5% co2 (balance air), the maximum growth rate of the photoautotrophic cell line was a 400% fresh weight increase in eight days. the chl concentration was approximately 500 μg per g fresh weight.elevated co2 (1%-5%) was required for culture growth, while the ambient air of the culture room (600 to 700 ul co2 1 ...	1988	24241763
copy numbers of chloroplast and nuclear genomes are proportional in mature mesophyll cells of triticum and aegilops species.	the possibility of estimating the proportion of chloroplast dna (ctdna) and nuclear dna (ndna) in nucleic-acid extracts by selective digestion with the methylation-sensitive restriction enzyme psti, was tested using leaf extracts from spinacia oleracea and triticum aestivum. values of ctdna as percentage ndna were estimated to be 14.58%±0.56 (se) in s. oleracea leaves and 4.97%±0.36 (se) in t. aestivum leaves. these estimates agree well with those already reported for the same type of leaf mater ...	1986	24241861
inhibition of photosynthetic reactions by light : a study with isolated spinach chloroplasts.	illumination of isolated intact chloroplasts of spinacia oleracea l. for 10 min with 850 w m(-2) red light in the absence of substrate levels of bicarbonate caused severe inhibition of subsequently measured photosynthetic activities. the capacity of co2-dependent o2 evolution and of non-cyclic electron transport were impaired to similar degrees. this photoinactivation was prevented by addition of bicarbonate which allowed normal carbon metabolism to proceed during preillumination. photoinhibitio ...	1985	24249342
development of cytosol and chloroplast aldolases during germination of spinach seeds.	the total activity of aldolase (ec 4.1.2.13) and the activities of cytosol and chloroplast aldolase were determined in seeds, cotyledons, primary leaves and secondary leaves of spinach (spinacia oleracea l., cv. monopa) during germination. total aldolase activity in cotyledons increased from low levels to a low maximum in the dark after one week and to a high maximum in white light after three to four weeks and declined thereafter. the activity in primary and secondary leaves started to rise str ...	1985	24249508
spectrophotometric determination of cu(2+) and monitoring of hg(2+) and ni(2+) in some iranian vegetables using 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione.	recently, 6-(2-naphthyl)-2, 3-dihydro-as-triazine-3-thione (ndtt) was synthesized in laboratory and used successfully for the spectrophotometric determination of nanogram levels of cu(2+) in aqueous solution. this reagent forms a specific red complex with cu(2+) ions after the extraction by chloroform at alkaline ph. the absorption of the complex in the uv region (313 nm) is about 8 times as strong as in the visible one (510 nm). mercury and nickel ions form yellow complexes with ndtt under the ...	2013	24250566
construction and mapping of safflower chloroplast dna recombinants and location of selected gene markers.	dna was isolated and purified from chloroplasts of safflower (carthamus tinctorius l.), digested with hindiii restriction endonuclease, and ligated into the hindiii site of the plasmid puc9. recombinant dnas were isolated from ampicillin resistant white colonies which grew in the presence of the appropriate indicator, digested with hindiii, and then identified by comparison of agarose gel electrophoretic mobilities. hindiii digests of chloroplast dna were used as a standard. such recombinants we ...	1985	24253119
gene expression in cytokinin-and light-mediated plastogenesis of cucurbita cotyledons: ribulose-1,5-bisphosphate carboxylase/oxygenase.	the effects of a cytokinin (n(6)-benzyladenine, ba) and light on plastogenesis have been studied in detached cucurbita cotyledons using the key enzyme of photosynthetic co2 fixation, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubpcase), as an example of a coordinated program of plastid and nucleo-cytoplasmic gene expression. treatment of etiolated cotyledons with either ba in darkness or in light or light alone results in a marked and correlated stimulation of enzyme activity, quantity and ...	1984	24253161
thylakoid membrane stability in drought-tolerant and drought-sensitive plants.	the stress stability of membranes from two drought-tolerant plants (craterostigma plantagineum andceterach officinarum) was compared with that of a drought-sensitive plant (spinacia oleracea) in model experiments. thylakoids from these plants were exposed to excessive sugar or salt concentrations or to freezing. all stresses caused loss of membrane function as indicated by the loss of cyclic photophosphorylation or the inability of the membranes to maintain a large proton gradient in the light. ...	1984	24253553
the co2/o 2 specificity of ribulose 1,5-bisphosphate carboxylase/oxygenase : dependence on ribulosebisphosphate concentration, ph and temperature.	the substrate specificity factor, v cko/vokc, of spinach (spinacia oleracea l.) ribulose 1,5-bisphosphate carboxylase/oxygenase was determined at ribulosebisphosphate concentrations between 0.63 and 200 μm, at ph values between 7.4 and 8.9, and at temperatures in the range of 5° c to 40° c. the co2/o2 specificity was the same at all ribulosebisphosphate concentrations and largely independent of ph. with increasing temperature, the specificity decreased from values of about 160 at 5° c to about 5 ...	1984	24253719
pyridine nucleotides and redox-charge evolution during the induction of flowering in spinach leaves.	in the long-day plant spinacia oleracea changes in the pool size of pyridine nucleotides have been followed under different photoperiodic conditions. in short days (vegetative state), the dark and light phases of the cycle are characterized by specific reciprocal changes in nad and nadp pool sizes. as a consequence, the ratios of nadh/nad+nadh and nadph/nadp+nadph, which are respectively considered to represent the catabolic and anabolic state of metabolism, also show a characteristic pattern. u ...	1983	24258176
inhibited light activation of fructose and sedoheptulose bisphosphatase in spinach chloroplasts exposed to osmotic stress.	the light activation of fructose-1,6-bisphosphatase (ec 3.1.3.11) and sedoheptulose-1,7-bisphosphatase (ec 3.1.3.37) was inhibited in isolated intact spinach (spinacia oleracea l.) chloroplasts exposed to reduced osmotic potentials. decreases in the velocity and magnitude of light activation correlated with the overall reduction in co2 fixation rates. responses of osmotically stressed chloroplasts to both varying ph and exogeous dihydroxyacetone phosphate (dhap) or 3-phosphoglycerete (pga) were ...	1984	24258369
the uptake of gibberellin a1 by suspension-cultured spinacia oleracea cells has a carrier-mediated component.	the kinetics of the uptake of [(3)h]gibberellin a1 (ga1) by light- and dark-grown suspension-cultured cells of spinacia oleracea (spinach) have been studied. use of nonradioactive ga1 and gibberellic acid (ga3) show that the uptake has a saturable and a nonsaturable component. the nonsaturable component increases as the ph is lowered at a fixed concentration of [(3)h]ga1 and is probably caused by non-mediated diffusion of the uncharged protonated species of ga1. the saturable component is not th ...	1984	24258671
calmodulin-dependent and independent nad kinase activities from cytoplasmic and chloroplastic fractions of spinach (spinacia oleracea l.).	nad kinase activity has been found in a soluble, cytoplasmic fraction and in the chloroplasts prepared from green spinach leaves. a small amount of both the cytoplasmic and the chloroplastic nad kinase activities was retained on a calmodulin-sepharose affinity column. the cytoplasmic nad kinase eluted from the affinity column was found to be enhanced by calmodulin in a ca(2+)-dependent manner. the chloroplastic enzyme which is located exclusively in the stroma and not in the envelope and thylako ...	1982	24259024
ribulose 1,5-bisphosphate carboxylase and phosphoribulokinase in prochloron.	cell-free extracts of prochloron didemni were assayed for ribulose 1,5-bisphosphate (rubp) carboxylase (ec 4.1.1.39) and phosphoribulokinase (ec 2.7.1.19), two key enzymes in the reductive pentose-phosphate cycle. in an rubp-dependent reaction, the production of two molecules of 3-phosphoglycerate per molecule of co2 fixed was shown. phosphoribulokinase activity was demonstrated by the production of adp from ribulose 5-phosphate (ru5p) and atp and by measurement of atp-, ru5p-dependent (14)co2 f ...	1983	24264746
in-vitro degradation of starch granules isolated from spinach chloroplasts.	the initial reactions of transitory starch degradation in spinacia oleracea l. were investigated using an in-vitro system composed of native chloroplast starch granules, purified chloroplast and non-chloroplast forms of phosphorylase (ec 2.4.1.1) from spinach leaves, and α-amylase (ec 3.2.1.1) isolated from bacillus subtilis. starch degradation was followed by measuring the release of soluble glucans, by determining phosphorylase activity, and by an electron-microscopic evaluation following deep ...	1983	24264852
molecular characterization of two glutathione peroxidase genes of panax ginseng and their expression analysis against environmental stresses.	glutathione peroxidases (gpxs) are a group of enzymes that protect cells against oxidative damage generated by reactive oxygen species (ros). gpx catalyzes the reduction of hydrogen peroxide (h2o2) or organic hydroperoxides to water or alcohols by reduced glutathione. the presence of gpxs in plants has been reported by several groups, but the roles of individual members of this family in a single plant species have not been studied. two gpx cdnas were isolated and characterized from the embryoge ...	2014	24269671
chimaeric cp47 mutants of the cyanobacterium synechocystis sp. pcc 6803 carrying spinach sequences: construction and function.	chimaeric mutants of the cyanobacterium synechocystis sp. pcc 6803 have been generated carrying part or all of the spinach psbb gene, encoding cp47 (one of the chlorophyll-binding core antenna proteins in photosystem ii). the mutant in which the entire psbb gene had been replaced by the homologous gene from spinach was an obligate photoheterotroph and lacked photosystem ii complexes in its thylakoid membranes. however, this strain could be transformed with plasmids carrying selected regions of s ...	1996	24271295
purification and identification of the violaxanthin deepoxidase as a 43 kda protein.	violaxanthin deepoxidase (vde) has been purified from spinach (spinacia oleracea) leaves. the purification included differential sonication of thylakoid membranes, differential (nh4)2so4 fractionation, gel filtration chromatography and finally either hydrophobic interaction chromatography or anion exchange chromatography. a total purification of more than 5000-fold compared to the original thylakoids enabled the identification of a 43 kda protein as the vde, in contrast to earlier reported molec ...	1996	24271609
a comparative flash-photolysis study of electron transfer from pea and spinach plastocyanins to spinach photosystem 1. a reaction involving a rate-limiting conformational change.	two mutants of plastocyanin have been constructed by site-directed mutagenesis in spinach and pea to elucidate the binding and electron transfer properties between plastocyanin and spinach photosystem 1. the conserved, surface-exposed tyr-83 has been replaced by phenylalanine and leucine in plastocyanin from both species and the proteins have been expressed in escherichia coli. the reaction mechanism of electron transfer from plastocyanins to photooxidized p700 in photosystem 1 has been studied ...	1996	24271818
the properties of transketolase from photosynthetic tissue.	transketolase (e.c. 2.2.1.1.) has been partially purified from wheat (triticum aestivum, cv. sappo) and spinach (spinacia oleracea) leaves. the fully-active enzyme is a tetramer of relative molecular mass (mr) of 150 kmr requiring thiamin pyrophosphate for maximal activity, and dissociating into a 74 kmr dimer in its absence or in dilute solution. the chloroplastic transketolase (over 75% of the cellular total) is magnesium-stimulated but the cytosolic form is magnesium-insensitive. both chlorop ...	1982	24271866
carbohydrate and carbon metabolite accumulation responses in leaves of ozone tolerant and ozone susceptible spinach plants after acute ozone exposure.	the objective of this study was to determine whether exposure of plants to ozone (o3) increased the foliar levels of glucose, glucose sources, e.g., sucrose and starch, and glucose-6-phosphate (g6p), because in leaf cells, glucose is the precursor of the antioxidant, l-ascorbate, and glucose-6-phosphate is a source of nadph needed to support antioxidant capacity. a further objective was to establish whether the response of increased levels of glucose, sucrose, starch and g6p in leaves could be c ...	1996	24271929
the reactivation of nitrate reductase from spinach (spinacea oleracea l.) inactivated by nadh and cyanide: effects of peroxidase and associated systems.	nitrate reductase of spinach (spinacea oleracea l.) leaves which had been inactivated in vitro by treatment with nadh and cyanide, was reactivated by incubation with oxidant systems and measured as fmnh2-dependent activity. ferricyanide, a purely chemical oxidant, produced rapid maximal reactivation (100%) which was 90% complete in less than 3 min. reactivation occurred slowly and less completely (30-75% in 30 or 60 min) when the enzyme was incubated with pure horseradish peroxidase alone, depen ...	1982	24272572
expression of an active spinach acyl carrier protein-i/protein-a gene fusion.	a synthetic gene encoding spinach acyl carrier protein i (acp-i) was fused to a gene encoding the fc-binding portion of staphylococcal protein a. this gene fusion, under the control of the λpr promoter, was expressed at high levels in escherichia coli producing a 42 kda fusion protein. this fusion protein was phosphopantethenylated in e. coli. in vitro the acp portion of the fusion protein was able to participate in acyl acp synthetase reactions, plant malonyl-coa:acp transacylase (mct) reaction ...	1989	24272721
transformation of arsenic species during in vitro gastrointestinal digestion of vegetables.	arsenic is an element widely distributed in the environment, and the diet is the main source of arsenic exposure for most people. however, many of the processes related to steps before intestinal absorption are unknown. this study evaluates the effect of in vitro gastrointestinal digestion on pentavalent arsenic forms [as(v), mma(v), dma(v)] present in various vegetables (garlic, broccoli, asparagus, spinach) after soaking or boiling in aqueous solutions of these species. the results showed that ...	2013	24274313
characterization of maltose biosynthesis from α-d-glucose-1-phosphate in spinacia oleracea. l.	the de novo synthesis of maltose in spinach (spinacia oleracea l.) was shown to be catalyzed by a maltose synthase, which converts two molecules of α-d-glucose-1-phosphate (α-g1p) (km 1.5 mmol l(-1)) to maltose and 2 orthophosphate (pi). this enzyme was purified 203-fold by fractionated ammonium sulfate precipitation and by column chromatography on sepharose 6b. the addition of α-g1p (15 mmol l(-1)) to the isolation buffer is required to stabilize the enzyme activity during the extraction and pu ...	1982	24275923
restriction endonuclease cleavage site map of chloroplast dna from oenothera parviflora (euoenothera plastome iv).	1) more than 50 cleavage sites produced by the restriction endonucleases sal i, pst i, kpn i, sma i and eco ri have been physically mapped on the 47 μm circular dna molecule of the euoenothera plastome iv. this plastome (= plastid genome) is considered to be the phylogenetically oldest of the subsection. 2) the dna molecule is segmentally organized into four regions represented by a large duplicated sequence in inverted orientation whose copies are separated by two single-copy segments. the sing ...	1981	24276512
metabolism and decarboxylation of glycollate and serine in leaf peroxisomes.	the linked utilization of glycollate and l-serine has been studied in peroxisomal preparations from leaves of spinach beet (beta vulgaris l.). the generation of glycine from glycollate was found to be balanced by the production of hydroxypyruvate from serine and similarly by 2-oxoglutarate when l-glutamate was substituted for l-serine. in the presence of l-malate and catalytic quantities of nad(+), about 40% of the hydroxypyruvate was converted further to glycerate, whereas with substrate quanti ...	1981	24276825
glutamate and serine as competing donors for amination of glyoxylate in leaf peroxisomes.	when provided with glycollate, peroxisomal extracts of leaves of spinach beet (beta vulgaris l. cv.) converted l-serine and l-glutamate to hydroxypyruvate and 2-oxoglutarate respectively. when approximately saturating concentrations of each of these amino acids were incubated separately with glycollate, the utilization of serine was greater than that of glutamate. the utilization of glutamate was substantially reduced by the presence of relatively low concentrations of serine in the reaction mix ...	1981	24276826
chlorella chloroplast dna sequence containing a gene for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase and a part of a possible gene for the β' subunit of rna polymerase.	the sequence of a 2782 bp fragment of the chloroplast genome of chlorella ellipsoidea has been determined. the region includes the entire gene (rbcl) for the large subunit (ls) of ribulose-1,5-bisphosphate carboxylase/oxygenase and a sequence (rpoc-like) similar to part of the gene for the subunit of e. coli rna polymerase which is oriented in same direction as rbcl. the arrangement is rpoc-like - 446 bp - rbcl. the rbcl gene codes for a polypeptide of 475 amino acids whose sequence shows 88% ho ...	1988	24277518
transcription study of the genes encoded in the region of the junction between the large single copy and the inverted repeat a of spinach chloroplast dna.	the expression of the psba, trnh-gug and rps19' genes from spinach chloroplasts, coding respectively for the 32 kda protein, the trna(his) (gug), and the putative ribosomal protein cs19', has been studied by cloning, northern hybridization and 3' and 5' s1 mapping experiments.it is demonstrated that the putative transcription termination signal of the psba gene does not function as a rho-independent terminator of transcription in e. coli, whatever its orientation.evidence is presented suggesting ...	1988	24277592
identification of an escherichia coli s1-like protein in the spinach chloroplast ribosome.	antibodies directed against e. coli ribosomal protein s1 were used in immunoblotting assays to search for an s1-like protein in the ribosome of spinach chloroplast. an immunological cross-reaction was reproducibly detected on the blots and inhibition experiments have demonstrated its specificity. the chloroplastic ribosomal protein which has epitopes common to antigenic determinants of the e. coli protein s1 was identified as being protein s2/s3.	1988	24277593
fascioliasis and intestinal parasitoses affecting schoolchildren in atlixco, puebla state, mexico: epidemiology and treatment with nitazoxanide.	the atlixco municipality, puebla state, at a mean altitude of 1840 m, was selected for a study of fasciola hepatica infection in schoolchildren in mexico. this area presents permanent water collections continuously receiving thaw water from popocatepetl volcano (5426 m altitude) through the community supply channels, conforming an epidemiological scenario similar to those known in hyperendemic areas of andean countries.	2013	24278492
synthesis and biological evaluation of 2-hydroxy-3-[(2-aryloxyethyl)amino]propyl 4-[(alkoxycarbonyl)amino]benzoates.	a series of twenty substituted 2-hydroxy-3-[(2-aryloxyethyl)amino]propyl 4-[(alkoxycarbonyl)amino]benzoates were prepared and characterized. as similar compounds have been described as potential antimycobacterials, primary in vitro screening of the synthesized carbamates was also performed against two mycobacterial species. 2-hydroxy-3-[2-(2,6-dimethoxyphenoxy)ethylamino]-propyl 4-(butoxycarbonylamino)benzoate hydrochloride, 2-hydroxy-3-[2-(4-methoxyphenoxy)ethylamino]-propyl 4-(butoxycarbonylam ...	2013	24288475
identification of novel antimicrobial resistance genes from microbiota on retail spinach.	drug resistance genes and their mobile genetic elements are frequently identified from environmental saprophytic organisms. it is widely accepted that the use of antibiotics in animal husbandry selects for drug resistant microorganisms, which are then spread from the farm environment to humans through the consumption of contaminated food products. we wished to identify novel drug resistance genes from microbial communities on retail food products. here, we chose to study the microbial communitie ...	2013	24289541
inhibition of escherichia coli o157:h7 and salmonella enterica on spinach and identification of antimicrobial substances produced by a commercial lactic acid bacteria food safety intervention.	the microbiological safety of fresh produce is of concern for the u.s. food supply. members of the lactic acid bacteria (lab) have been reported to antagonize pathogens by competing for nutrients and by secretion of substances with antimicrobial activity, including organic acids, peroxides, and antimicrobial polypeptides. the objectives of this research were to: (i) determine the capacity of a commercial lab food antimicrobial to inhibit escherichia coli o157:h7 and salmonella enterica on spinac ...	2014	24290643
dark-adapted spinach thylakoid protein heterogeneity offers insights into the photosystem ii repair cycle.	in higher plants, thylakoid membrane protein complexes show lateral heterogeneity in their distribution: photosystem (ps) ii complexes are mostly located in grana stacks, whereas psi and adenosine triphosphate (atp) synthase are mostly found in the stroma-exposed thylakoids. however, recent research has revealed strong dynamics in distribution of photosystems and their light harvesting antenna along the thylakoid membrane. here, the dark-adapted spinach (spinacia oleracea l.) thylakoid network w ...	2014	24296034
photoinhibition of photosystem i electron transfer activity in isolated photosystem i preparations with different chlorophyll contents.	photoinhibition of the light-induced photosystem i (ps i) electron transfer activity from the reduced dichlorophenol indophenol to methyl viologen was studied. ps i preparations with chl/p700 ratios of about 180 (ps i-180), 100 (ps i-100) and 40 (ps i(ha)-40) were isolated from spinach thylakoid membranes by the treatments with triton x-100, followed by sucrose density gradient centrifugation and hydroxylapatite column chromatography. white light irradiation (1.1 × 10(4)μe m(-2) s(-1)) of ps i-1 ...	1996	24301820
freezing injury in cold-acclimated and unhardened spinach leaves : i. photosynthetic reactions of thylakoids isolated from frost-damaged leaves.	spinach plants (spinacia oleracea l.) were frost-hardened by cold-acclimation to 1° c or kept in an unhardy state at 20°/14° c in phytotrons. detached leaves were exposed to temperatures below 0°c. rates of photosynthetic co2 uptake by the leaves, recorded after frost treatment, served as a measure of freezing injury. thylakoid membranes were isolated from frost-injured leaves and their photosynthetic activities tested. ice formation occurred at about-4° to-5° c, both in unhardened and cold-accl ...	1981	24301976
freezing injury in cold-acclimated and unhardened spinach leaves : ii. effects of freezing on chlorophyll fluorescence and light scattering reactions.	leaves from cold-acclimated and from unhardened spinach plants (spinacia oleracea l.) were subjected to a freezing/thawing procedure in which varying minimum temperatures were reached. subsequently, the chlorophyll fluorescence induction signal (kautsky phenomenon) and the light-induced apparent absorbance changes at 535 nm (light-scattering changes indicative of the proton gradient, and absorbance changes induced by the membrane potential) of the leaves were studied to obtain information on the ...	1981	24301977
characterization of the spinach chloroplast genes for the s4 ribosomal protein, trna(thr) (ugu) and trna (ser) (gga).	the map location and nucleotide sequence of the genes for the s4 ribosomal protein (rps4) and for trna(thr) (ugu) (trnt) and trna(ser) (gga) (trns) on spinach chloroplast dna have been determined. rps4 lies approximately 5 kb 3' to atpbe in the large single copy region and is transcribed in the same direction as atpbe. it has a 178 bp leader sequence, a 603 bp coding region and 620 bp 3' tail. the sequence of the coding region is 83% homologous with that of maize rps4 (29) and the deduced amino ...	1986	24302158
an ultrastructural search for lectin-binding sites on surfaces of spinach leaf organelles.	organelles isolated from leaves of spinach (spinacia oleracea l.) were prefixed in glutaraldehyde and then incubated with ferritin conjugates of four lectins - concanavalin a (con a), ricinus communis l. agglutinin, mw 120,000 (rca), soybean agglutinin (sba), and wheat germ agglutinin (wga) - in order to probe their cytoplasmic surfaces for saccharide residues. in each case the major leaf organelles, including microbodies, mitochondria and chloroplast derivatives, failed to exhibit labeling when ...	1981	24302382
adenine nucleotides and energy charge evolution during the induction of flowering in spinach leaves.	changes in adenine nucleotides pool size levels have been investigated in spinach leaves (spinacia oleracea. l. cv. nobel) in order to characterize the transition from the vegetative to the reproductive development. the transient changes reported in this study are the earliest responses observed to date in leaves during photoperiodic induction. these results are discussed in relation to prigogine's theory of systems far from equilibrium.	1981	24302414
effects of freezing on isolated plant mitochondria.	mitochondria isolated from spinach leaves (spinacia oleracea l.) and potato tubers (solanum tuberosum l.) were partly injured when subjected to freezing for 2 to 4 h at-25°c in salt solutions in the absence of cryoprotectants. damage was manifested by the inactivation of respiratory properties and increase in the permeability of the mitochondrial membranes. decrease in respiratory control indicated that the control mechanism of the electron transport chain was influenced by freezing. oxidative p ...	1981	24302422
effects of ph and other factors on the phosphate dependence of photosynthesis in spinach chloroplasts.	chloroplast stromal volume and ph influenced the phosphate (pi)-dependence of photosynthesis of spinach (spinacia oleracea l.) chloroplasts. decreasing the sorbitol concentration in the reaction mixture from 0.35 to 0.25 m, or decreasing the external ph from 8.3 to 7.3, extended the induction period of photosynthesis and decreased both the optimal [pi] and the minimal [pi] required to inhibit o2 evolution completely. at least part of the effect of external ph was attributable to changes in strom ...	1980	24306478
the reactivation of nitrate reductase from spinach (spinacia oleracea l.) inactivated by nadh and cyanide, using trivalent manganese either generated by illuminated chloroplasts or as manganipyrophosphate.	nitrate reductase of spinach (spinacia oleracea l.) leaves which had been inactivated in vitro by treatment with nadh and cyanide, was reactivated by incubation with oxidant systems and measured as fmnh2-dependent activity. reactivation was produced with trivalent manganese compounds represented either by manganipyrophosphate or produced by oxidation of mn(2+) ions in the presence of illuminated chloroplasts and compared with reactivation obtained with ferricyanide. reactivation in the chloropla ...	1980	24306689
organization and nucleotide sequence of the genes for spinach chloroplast trna(glu) and trna (tyr.).	the map location and nucleotide sequence of the genes and flanking regions for trnauuc (glu) (trne) and trnagua (tyr) (trny) from spinach (spinacia oleracea) chloroplast dna have been determined. the genes lie approximately midway between the genes for trnaggu (thr) (trnt) and trnaguc (asp) (trnd) on bamh1 fragment 8b, the arrangement being trnt, 458 bp, trne, 64 bp, trny, 409 bp, trnd. trne and trny are encoded by the same dna strand as trnd and the direction of their transcription is divergent ...	1984	24310516
physical and genetic mapping of safflower chloroplast dna : location of psba, rbcl, atpa and rrna.	a physical map of safflower (carthamus tinctorius l.) chloroplast dna has been generated using sali, psti, kpni and hindiii restriction endonucleases. the circular plastid genome (151 kbp) has the usual inverted repeat. heterologous probes containing psba, rbcl, atpa or rrna structural genes mapped colinearly with spinach and other chloroplast genomes.	1985	24310941
modulation of glucose-6-phosphate dehydrogenase by nadph, nadp(+) and dithiothreitol at variable nadph/nadp (+) ratios in an illuminated reconstituted spinach (spinacia oleracea l.) chloroplast system.	the light-dependent inhibition of glucose-6-phosphate dehydrogenase (ec 1.1.1.49), the key enzyme of the oxidative pentose phosphate cycle, can be gradually abolished in an illuminated reconstituted spinach chloroplast system by increasing the concentration of nadp(+). the inhibition caused by the effector which was produced by the system in the light is characterized as being of the competitive type with respect to nadp(+). the ki value is 0.070 mm. the addition of nadph to the illuminated reco ...	1980	24311258
chloroplast phenylalanine ammonia-lyase from spinach leaves : evidence for light-mediated regulation via the ferredoxin/thioredoxin system.	phenylalanine ammonia-lyase (pal) from spinach (spinacia oleracea l.) leaves was resolved into three forms by diethyl-aminoethyl(deae)-cellulose chromatography. two forms were found in isolated chloroplasts, and the third form (the major component) was located outside of the chloroplasts. one of the chloroplast forms of the enzyme (designated the regulatory form) was activated by reduced thioredoxin. neither the other chloroplast form nor the extra-chloroplast form showed a response to thioredox ...	1979	24317559
a survey for isoenzymes of glucosephosphate isomerase, phosphoglucomutase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in c3-, c 4-and crassulacean-acid-metabolism plants, and green algae.	two isoenzymes each of glucosephosphate isomerase (ec 5.3.1.9), phosphoglucomutase (ec 2.7.5.1), glucose-6-phosphate dehydrogenase (ec 1.1.1.49) and 6-phosphogluconate dehydrogenase (ec 1.1.1.43) were separated by (nh4)2so4 gradient solubilization and deae-cellulose ion-exchange chromatography from green leaves of the c3-plants spinach (spinacia oleracea l.), tobacco (nicotiana tabacum l.) and wheat (triticum aestivum l.), of the crassulacean-acid-metabolism plants crassula lycopodioides lam., b ...	1979	24317570
clinical efficacy of a herbal dentifrice on dentinal hypersensitivity: a randomized controlled clinical trial.	dentinal hypersensitivity is a common problem and there is a growing interest in herbal based formulations for the treatment of oral diseases. this study was conducted to assess the efficacy of a commercially available novel herbal dentifrice in reduction of dentinal hypersensitivity.	2013	24320906
regio- and stereospecific hydroxylation of various steroids at the 16α position of the d ring by the streptomyces griseus cytochrome p450 cyp154c3.	cytochrome p450 monooxygenases (p450s), which constitute a superfamily of heme-containing proteins, catalyze the direct oxidation of a variety of compounds in a regio- and stereospecific manner; therefore, they are promising catalysts for use in the oxyfunctionalization of chemicals. in the course of our comprehensive substrate screening for all 27 putative p450s encoded by the streptomyces griseus genome, we found that escherichia coli cells producing an s. griseus p450 (cyp154c3), which was fu ...	2014	24334658
effect of edta washing of metal polluted garden soils. part ii: can remediated soil be used as a plant substrate?	in a field experiment on metal contaminated and edta-remediated soil we studied plant performance, mycorrhizal associations and prospects of potential re-use of remediated soil as a garden substrate. two experimental plots of 4 × 1 × 0.3 m were filled, one with remediated and the other with original contaminated soil. selected cultivars were rotated over the course of 16months. pb, zn, cd and micronutrient plant uptake was measured and their phytoaccessibility was analyzed by the dtpa method. pl ...	2014	24342493
the genome of the recently domesticated crop plant sugar beet (beta vulgaris).	sugar beet (beta vulgaris ssp. vulgaris) is an important crop of temperate climates which provides nearly 30% of the world's annual sugar production and is a source for bioethanol and animal feed. the species belongs to the order of caryophylalles, is diploid with 2n = 18 chromosomes, has an estimated genome size of 714-758 megabases and shares an ancient genome triplication with other eudicot plants. leafy beets have been cultivated since roman times, but sugar beet is one of the most recently ...	2014	24352233
using spinach-based sensors for fluorescence imaging of intracellular metabolites and proteins in living bacteria.	genetically encoded fluorescent sensors can be valuable tools for studying the abundance and flux of molecules in living cells. we recently developed a novel class of sensors composed of rnas that can be used to detect diverse small molecules and untagged proteins. these sensors are based on spinach, an rna mimic of gfp, and they have successfully been used to image several metabolites and proteins in living bacteria. here we discuss the generation and optimization of these spinach-based sensors ...	2014	24356773
molecular approaches toward targeted cancer prevention with some food plants and their products: inflammatory and other signal pathways.	in recent years, there has been growing interest in cancer prevention by food plants and their products. although several plant parts have potentials for chemoprevention and other therapeutic use, their molecular mechanisms of action are not always well understood. extensive research has identified several molecular targets that can potentially be used for the prevention and/or treatment of cancer. in this review, we accumulate evidences of modulating abilities of some dietary plants and their p ...	2014	24377653
a practical approach to minimize the interaction of dietary vitamin k with warfarin.	the many interactions between warfarin and other drugs and foods generate great challenges for clinicians and patients in maintaining stable anitcoagulation. interactions due to variable vitamin k content of different dietary items influence the therapy of nearly all patients on warfarin. unfortunately, there is no widely acceptable, patient-friendly strategy for managing such interactions. in this contribution, we propose a practical approach to managing this troublesome interaction, consisting ...	2014	24383939
oxalate content of foods and its effect on humans.	oxalic acid and its salts occur as end products of metabolism in a number of plant tissues. when these plants are eaten they may have an adverse effect because oxalates bind calcium and other minerals. while oxalic acid is a normal end product of mammalian metabolism, the consumption of additional oxalic acid may cause stone formation in the urinary tract when the acid is excreted in the urine. soaking and cooking of foodstuffs high in oxalate will reduce the oxalate content by leaching. the mea ...	1999	24393738
n-substituted 5-amino-6-methylpyrazine-2,3-dicarbonitriles: microwave-assisted synthesis and biological properties.	in this work a series of 15 n-benzylamine substituted 5-amino-6-methyl-pyrazine-2,3-dicarbonitriles was prepared by the aminodehalogenation reactions using microwave assisted synthesis with experimentally set and proven conditions. this approach for the aminodehalogenation reaction was chosen due to its higher yields and shorter reaction times. the products of this reaction were characterized by ir, nmr and other analytical data. the compounds were evaluated for their antibacterial, antifungal a ...	2014	24402198
quantifying the sensitivity of scent detection dogs to identify fecal contamination on raw produce.	consumption of raw produce commodities has been associated with foodborne outbreaks in the united states. in a recent centers for disease control and prevention report outlining the incidence of food-related outbreaks from 1998 to 2008, produce of all kinds were implicated in 46% of illnesses and 23% of deaths. methods that quickly identify fecal contamination of foods, including produce, will allow prioritization of samples for testing during investigations and perhaps decrease the time require ...	2014	24405993
high-frequency oscillations and circadian rhythm of the membrane potential in spinach leaves.	the microelectrode technique was used to follow oscillations in membrane potential in mesophyll cells of spinach (spinacia oleracea l.) during exposure do different photoperiodic conditions. both high-frequency oscillations and circadian variations were observed. the circadian rhythm was imposed on the period of high-frequency oscillation during short days as well as in continuous light: the free-running period was 25.2 h. the average period of high-frequency oscillation increased from 7.64 min ...	1979	24407253
effect of growth regulators and role of roots in sex expression in spinach.	when 7-d-old plantlets of spinach (spinacia oleracea l.) were immersed with their roots for 24 h in 25 mg/l gibberellic acid (ga3), or 15 mg/l 6-benzylaminopurine (6-bap), or 15 mg/l indole-3-acetic acid (iaa), or 10 mg/l abscisic acid (aba) and subsequently grown on long (18-h) days, the ratio of plants with male and female flowers, which in the controls was almost 1:1 (48 and 52%, respectively), was greatly altered. the treatments with 6-bap, iaa and aba raised the percentage of female plants ...	1978	24408104
o2-dependent inhibition of photosynthetic capacity in intact isolated chloroplasts and isolated cells from spinach leaves illuminated in the absence of co2.	when isolated intact chloroplasts or cells from spinach (spinacia oleracea l.) leaves are incubated in the light in the absence of co2, their capacity for subsequent co2-dependent photosynthetic oxygen evolution is drastically decreased. this inhibition is light and oxygen-dependent and can be prevented by addition of bicarbonate. it is concluded that the normal dissipation of photosynthetic energy by carbon assimilation and in processes related to photorespiration is an essential condition for ...	1978	24408108
regulation of photosynthetic electron transport and photophosphorylation in intact chloroplasts and leaves of spinacia oleracea l.	oxygen ist reduced by the electron transport chain of chloroplasts during co2 reduction. the rate of electron flow to oxygen is low. since antimycin a inhibited co2-dependent oxygen evolution, it is concluded that cyclic photophosphorylation contributes atp to photosynthesis in chloroplasts which cannot satisfy the atp requirement of co2 reduction by electron flow to nadp and to oxygen. inhibition of photosynthesis by antimycin a was more significant at high than at low light intensities suggest ...	1978	24408259
cell organelles from crassulacean-acid-metabolism (cam) plants : i. enzymes in isolated peroxisomes.	cell organelles were isolated from the cam plants crassula lycopodioides lam., bryophyllum calycinum salisb. and sedum rubrotinctum r.t. clausen by isopycnic centrifugation in sucrose gradients. the inclusion of 2.5% ficoll in the grinding medium proved to be essential for a satisfactory separation of cell organelles during the subsequent centrifugation. peroxisomes, mitochondria, and whole and broken chloroplasts were at least partially resolved as judged by marker-enzyme-activity profiles. the ...	1978	24408466
localization of adenosine 5'-phosphosulfate sulfotransferase in spinach leaves.	roots of spinach (spinacia oleracea l.) seedlings contained only a very low activity of adenosine 5'-phosphosulfate sulfotransferase compared to the cotyledons. adenosine 5'-phosphosulfate sulfotransferase activity increased about tenfold in cotyledons during greening. preparation of organelle fractions from spinach leaves by a combination of differential and isopycnic density gradient centrifugation showed that adenosine 5'-phosphosulfate sulfotransferase banded with nadp-glyceraldehyde-3-phosp ...	1978	24408467
the role of leaves in sex expression in hemp and spinach.	when shoots of young plants of hemp (cannabis sativa l.) and spinach (spinacea oleracea l.) were cultured as cuttings and allowed to regenerate advenitious roots, ca. 80-85% became female (formed pistillate flowers) regardless of whether the leaves were left on the plants or were cut off (except for the 2-3 uppermost ones) after the beginning of adventitious-root formation. but when the leaves were cut off and the cuttings treated with gibberellic acid (ga3, 25 mg/l) ca. 77-80% of the plants bec ...	1979	24408695
inhibition of photosynthesis and respiration by batatasins.	effects of batatasins i, iii and v, phenolic growth inhibitors occuring in dormant bulbils of dioscorea batatas decne., on photosynthetic reactions of chloroplasts from spinach (spinacia oleracea l.) and on respiration of mitochondria from potatoes (solanum tuberosum l.) were investigated. in chloroplasts, the batatasins effectively inhibited co2-dependent oxygen evolution and electron flow from water to acceptors such as dichlorophenolindophenol, ferricyanide and methylviologen. photosystem-i d ...	1978	24414012
properties and physiological function of a glutathione reductase purified from spinach leaves by affinity chromatography.	glutathione reductase (ec 1.6.4.2) was purified from spinach (spinacia oleracea l.) leaves by affinity chromatography on adp-sepharose. the purified enzyme has a specific activity of 246 enzyme units/mg protein and is homogeneous by the criterion of polyacrylamide gel electrophoresis on native and sds-gels. the enzyme has a molecular weight of 145,000 and consists of two subunits of similar size. the ph optimum of spinach glutathione reductase is 8.5-9.0, which is related to the function it perf ...	1978	24414099
sources of reducing power for nitrate reduction in spinach leaves.	the possible source of nadh, the energy donor for nitrate reductase (ec 1.6.6.1), has been studied using an in vivo assay involving freezing the material (leaves of spinacea oleracea l.) in liquid nitrogen in order to render the tissue permeable to added substrates. glycolysis and the pentose phosphate pathway were capable of generating nadh through glyceraldehyde-3-phosphate dehydrogenase. malate and isocitrate were also capable of generating nadh white other organic acids tested were not, incl ...	1978	24414563
properties and intracellular distribution of two phosphoglucomutases from spinach leaves.	two isoenzymes of phosphoglucomutase from spinach (spinacia oleracea l.) leaves can be separated by ammonium-sulfate gradient solubilization or deae-cellulose ion exchange chromatography. they were designated as phosphoglucomutase 1 and 2, according to decreasing electrophoretic mobility towards the anode at ph 8.9. phosphoglucomutase 1 is localized in the stroma of the chloroplasts, phosphoglucomutase 2 is a cytosolic enzyme as judged from aqueous cell fractionation studies. both isoenzymes hav ...	1978	24414634
effect of phosphon-d on photosynthetic light reactions and on reactions of the oxidative and reductive pentose phosphate cycle in a reconstituted spinach (spinacia oleracea l.) chloroplast system.	phosphon-d (tributyl-2, 4-dichlorobenzylphosphonium chloride), known as an inhibitor of gibberellin biosynthesis, enhances photosynthetic electron transport by up to 200%, with fe(cn) 6 (3-) and nadp(+) being the electron acceptors. maximum stimulation is reached at phosphon-d concentrations around 2-5 μm. at the same time photosynthetic atp formation is gradually inhibited. phosphon-d concentrations over 0.1 mm inhibit electron transport. the uncoupling activity of phosphon-d is manifested by i ...	1978	24414777