Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| influence of antimycin a and uncouplers on anaerobic photosynthesis in isolated chloroplasts. | anaerobiosis depresses the light- and bicarbonate-saturated rates of o(2) evolution in intact spinach (spinacia oleracea) chloroplasts by as much as 3-fold from those observed under aerobic conditions. these lower rates are accelerated 2-fold or more by the addition of 1 mum antimycin a or by low concentrations of the uncouplers 0.3 mm nh(4)cl or 0.25 mum carbonyl cyanide m-chlorophenylhydrazone. oxaloacetate and glycerate 3-phosphate reduction rates are also increased by antimycin a or an uncou ... | 1977 | 16660133 |
| influence of ph upon the warburg effect in isolated intact spinach chloroplasts: ii. interdependency of glycolate synthesis upon ph and calvin cycle intermediate concentration in the absence of carbon dioxide photoassimilation. | the light-dependent synthesis of glycolate derived from fructose 1,6-diphosphate, ribose 5-phosphate, or glycerate 3-phosphate was studied in the intact spinach (spinacia oleracea) chloroplasts in the absence of co(2). glycolate yield increased with an elevation of o(2), ph, and the concentration of the phosphorylated compound supplied. no ph optimum was observed as the ph was increased from 7.4 to 8.5. the average maximal rate of glycolate synthesis was 50 mumoles per milligram chlorophyll per ... | 1977 | 16660122 |
| characterization of starch breakdown in the intact spinach chloroplast. | starch degradation with a rate of 1 to 2 microgram-atom carbon per milligram chlorophyll per hour was monitored in the isolated intact spinach (spinacia oleracea) chloroplast which had been preloaded with (14)c-starch photosynthetically from (14)co(2). starch breakdown was dependent upon inorganic phosphate and the (14)c-labeled intermediates formed were principally those of the embden-meyerhof pathway from glucose phosphate to glycerate 3-phosphate. in addition, isotope was found in ribose 5-ph ... | 1977 | 16660081 |
| chloroplast phosphofructokinase: ii. partial purification, kinetic and regulatory properties. | chloroplast phosphofructokinase from spinach (spinacia oleracea l.) was purified approximately 40-fold by a combination of fractionations with ammonium sulfate and acetone followed by chromatography on deae-sephadex a-50. positive cooperative kinetics was observed for the interaction between the enzyme and the substrate fructose 6-phosphate. the optimum ph shifted from 7.7 toward 7.0 as the fructose 6-phosphate concentration was taken below 0.5 mm. the second substrate was mgatp(2-) (michaelis c ... | 1977 | 16660079 |
| glucose transport into spinach chloroplasts. | the uptake of radioactively labeled hexoses and pentoses into the sorbitol-impermeable (3)h(2)o space (the space surrounded by the inner envelope membrane) of spinach (spinacia oleracea l.) chloroplasts has been studied using silicone layer filtering centrifugation. of the compounds tested, d-xylose, d-mannose, l-arabinose, and d-glucose are transported most rapidly, followed by d-fructose and l-arabinose. the rate of l-glucose uptake is only about 5% of that of d-glucose.the transport of d-gluc ... | 1977 | 16660077 |
| reversal of 3-(3,4-dichlorophenyl)-1,1-dimethylurea inhibition of carbon dioxide fixation in spinach chloroplasts and protoplasts by dicarboxylic acids. | 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu) inhibition of (14)co(2) fixation in isolated intact spinach (spinacia oleracea l.) chloroplasts was reversed (by about 34%) by l-malate but not by oxaloacetate (oaa). however, oaa reversed the dcmu inhibition in spinach protoplasts indicating an extrachloroplastic enzyme requirement. extrachloroplastic oaa reduction was coupled with external dihydroxyacetone phosphate (dhap) oxidation, and the malate formed from such coupling might then enter the ch ... | 1977 | 16660042 |
| effect of light and chilling temperatures on chilling-sensitive and chilling-resistant plants. pretreatment of cucumber and spinach thylakoids in vivo and in vitro. | the effects of chilling temperatures, in light or dark, on the isolated thylakoids and leaf discs of cucumber (cucumis sativa l. "marketer") and spinach (spinacia oleracea l. "bloomsdale") were studied. the pretreatment of isolated thylakoids and leaf discs at 4 c in the dark did not affect the phenazine methosulfate-dependent phosphorylation, proton uptake, osmotic response to sucrose, ca(2+)-dependent atpase activity, or chlorophyll content. exposure of cucumber cotyledon discs and isolated th ... | 1977 | 16659980 |
| inhibition of photosynthesis by azide and cyanide and the role of oxygen in photosynthesis. | cyanide and azide inhibit photosynthesis and catalase activity of isolated, intact spinach (spinacia oleracea) chloroplasts. when chloroplasts are illuminated in the presence of cn(-) or n(3) (-), accumulation of h(2)o(2) is observed, parallel to inhibition of photosynthesis. photosynthetic o(2) evolution is inhibited to the same extent, under saturating light, whether co(2) or phosphoglycerate is present as electron acceptor.the illumination of chloroplasts with cn(-) or n(3) (-) inactivates th ... | 1977 | 16659956 |
| chloroplast glutathione reductase. | glutathione reductase (ec 1.6.4.2) activity is present in spinach (spinacia oleracea l.) chloroplasts. the ph dependence and substrate concentration for half-maximal rate are reported and a possible role in chloroplasts is proposed. | 1977 | 16659940 |
| influence of ph upon the warburg effect in isolated intact spinach chloroplasts: i. carbon dioxide photoassimilation and glycolate synthesis. | the influence of ph upon the o(2) inhibition of (14)co(2) photoassimilation (warburg effect) was examined in intact spinach (spinacia oleracea) chloroplasts. with conditions which favored the warburg effect, i.e. rate-limiting co(2) and 100% o(2), o(2) inhibition was greater at ph 8.4 to 8.5 than at ph 7.5 to 7.8. at ph 8.5, as compared with 7.8, there was an enhanced (14)c-labeling of glycolate, and a decrease of isotope in some phosphorylated calvin cycle intermediates, particularly triose-pho ... | 1977 | 16659887 |
| evidence for alpha-tocopherol function in the electron transport chain of chloroplasts. | the effect of three different stable radicals-2,2-diphenyl-1-picrylhydrazyl, 1,3,5-triphenyl-verdazyl, and galvinoxyl-was studied in photosystem ii of spinach (spinacia oleracea) chloroplasts. inhibition by the three was noted on dimethylbenzoquinone reduction in presence of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (dbmib) and on silicomolybdate reduction in presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (dcmu) in photosystem ii and on the h(2)o --> methylviologen reaction encompassi ... | 1977 | 16659867 |
| nitrite reduction in reconstituted and whole spinach chloroplasts during carbon dioxide reduction. | nitrite reduction in either whole, isolated spinach chloroplasts (spinacia oleracea l.) or in reconstituted spinach chloroplasts is stimulated by a short period of photosynthetic co(2) fixation in the light prior to nitrite addition. with reconstituted chloroplasts, a similar stimulation can be obtained in nitrite reduction without co(2) fixation by the addition of dihydroxyacetone phosphate or fructose 6-phosphate. specific intermediate metabolites of the photosynthetic carbon reduction cycle m ... | 1977 | 16659813 |
| sulfate and sulfite translocation via the phosphate translocator of the inner envelope membrane of chloroplasts. | the permeability of the inner envelope membranes of spinach (spinacia oleracea) chloroplasts to sulfite and sulfate was investigated in vitro, using the technique of silicone oil centrifugal filtration. the results show that there is a permeability towards both ions, resulting in rates of uptake of about 1.0 (so 3 (2-) ) and 0.7 (so 4 (2-) ) μmol mg chlorophyll(-1) h(-1) respectively (external concentration 2 mmol l(-1)). the rates depend on the external concentration of the anions. anion exchan ... | 1977 | 24420671 |
| subcellular distribution of (35)s-sulfur in spinach leaves after application of (35)so 4 (2-) , (35)so 3 (2-) , and (35)so 2. | (35)so2, (35)so 3 (2-) , and (35)so 4 (2-) , respectively, were applied to leaves of spinacia oleracea l. for 60 min in the light. thereafter, the specific activity was determined in the organelles separated by means of sucrose density gradient centrifugation. in mitochondria and peroxisomes, the specific activity was equally distributed in their protein moieties. after application of (35)so2 or (35)so 3 (2-) , the chloroplast lamellae are characterized by elevated specific activity, which is no ... | 1977 | 24419888 |
| in-vitro interaction between chloroplasts and peroxisomes as controlled by inorganic phosphate. | peroxisomes, whole chloroplasts, mitochondria, and broken chloroplasts of spinach (spinacia oleracea l.), each form 1 band at its typical density, when isolated in sucrose gradients by isopycnic centrifugation in glycylglycine buffer. in potassium-phosphate buffer peroxisomes form a 2nd band at the density of whole chloroplasts. the phosphate effect is half-saturated at a concentration of 10-20 mm. if whole chloroplasts are removed by differential centrifugation before isopycnic centrifugation n ... | 1977 | 24419687 |
| cyclic nucleotide phosphodiesterase from spinacea oleracea l: subcellular distribution and properties [proceedings]. | 1977 | 199507 | |
| photosynthesis by isolated pea chloroplasts: some effects of adenylates and inorganic pyrophosphate. | when added singly to chloroplasts isolated from young pea (pisum sativum) leaves, both inorganic pyrophosphate (ppi) and small quantities (0.2 mm) of adp inhibit photosynthesis, but when added together they cause a marked stimulation. atp (at 0.2 mm) is less inhibitory (or not inhibitory) when added alone, but like adp, stimulates when added in the presence of ppi. this behavior is in marked contrast to that of spinach (spinacia oleracea) chloroplasts which are normally stimulated rather than in ... | 1977 | 16659866 |
| effect of fusicoccin on plant cell cultures and protoplasts. | we have assayed the capacity of the fungal toxin fusicoccin to induce some of its characteristic effects (acidification of the medium, stimulation of k(+), and of 3-o-methyl-d-glucose uptake) in cell suspensions of parthenocissus tricuspidata (siebold et zucc.) planchon, acer pseudoplatanus l. and oryza sativa l., and in protoplast suspensions prepared from leaves of nicotiana tabacum l. and spinacia oleracea l. or from cultures of p. tricuspidata. evidence is presented showing that all tested b ... | 1977 | 24420024 |
| qualitative and quantitative immunofluorescence studies of chloroplast ferredoxin : application to investigations of ferredoxin inheritance in nicotiana hybrids. | antibodies were raised in rabbits against 2fe-2s ferredoxin from n. tabacum l. the antibodies showed partial cross-reactivity in the double diffusion test with ferredoxins from spinacia oleracea l., petunia inflata fries., p. axillaris lam., phaseolus vulgaris l., chlamydomonas remhardii dang. a complete cross-reaction was observed with ferredoxins from five other nicotiana species, thus with this test it was impossible to discriminate between these ferredoxins. therefore the following test was ... | 1977 | 24420666 |
| the effect of temperature on glycollate decarboxylation in leaf peroxisomes. | [1-(14)c]glycollate was oxidised to(14)co2 by peroxisomes isolated from leaves of spinach beet about 3 times as rapidly at 35°c as at 25°c; the rate was further increased with rise in temperature to a maximum at 55°c. these increases are shown to be mainly due to the increased h2o2 available to oxidise glyoxylate non-enzymically as a result of the higher temperature coefficient of glycollate oxidase activity relative to that of catalase. these results are compared with similar increases in the r ... | 1977 | 24425260 |
| [fluorescent properties of b-type ferredoxins]. | fluroescent spectra of six b-type ferredoxins of plant and animal origins were obtained. all investigated proteins do not contain tryptophan. the emission maxima of the native proteins, apoproteins prepared by various methods, and denaturated proteins are compared. the effects of ph, ionic strength and ferricyanide on the ferredoxins fluorescence were studied. "unusual" emission at 340nm noted previously for adrenal ferredoxin was observed for spinach and chenopodium album ferredoxins too. the l ... | 1977 | 19104 |
| modifications induced by benomyl and related compounds into chloroplasts spectral patterns, photosynthetic rates and chlorophyll contents of spinacia oleracea and cucumis melo. | 1977 | 861396 | |
| different molecular forms of d-ribulose-1,5-bisphosphate carboxylase from rhodopseudomonas sphaeroides. | ribulose-1,5-bisphosphate (rbu-p2) carboxylase isolated from rhodopseudomonas sphaeroides 2.4.1.ga was separated into two different forms by deae-cellulose column chromatography. both forms, designated peak i and peak ii have been purified to homogeneity by the criterion of polyacrylamide disc-gel electrophoresis. the peak i carboxylase has a molecular weight of 550,000, while the peak ii carboxylase is a smaller protein having a molecular weight of approximately 360,000. sodium dodecyl sulfate ... | 1977 | 14141 |
| phosphoribulokinase from nitrobacter winogradskyi: activation by reduced nicotinamide adenine dinucleotide and inhibition by pyridoxal phosphate. | co2 fixation by particle-free extracts from nitrobacter winogradskyi increased by addition of reduced nicotinamide adenine dinucleotide (nadh). ribulose-1,5-diphosphate, however, increased co2 fixation, even in the absence of nadh. phosphoribulokinase (ec 2.7.1.19) was the enzyme of nitrobacter extracts that was activated specifically by nadh. pyridoxal-5-phosphate inhibited both co2 fixation and nadh-activated phosphoribulokinase from nitrobacter. however, it did not affect phosphoribulokinase ... | 1977 | 15976 |
| adenosine-5'-phosphosulfate (aps) as sulfate donor for assimilatory sulfate reduction in rhodospirillum rubrum. | crude extracts of rhodospirillum rubrum catalyzed the formation of acid-volatile radioactivity from (35s) sulfate, (35s) adenosine-5'-phosphosulfate, and (35s) 3'-phosphoadenosine-5'-phosphosulfate. an enzyme fraction similar to aps-sulfotransferases from plant sources was purified 228-fold from rhodospirillum rubrum. it is suggested here that this enzyme is specific for adenosine-5'-phosphosulfate, because the purified enzyme fraction metabolized adenosine-5'-phosphosulfate; 3'-phosphoadenosine ... | 1977 | 16577 |
| the stereospecificity of nitrate reductase for hydrogen removal from reduced pyridine nucleotides. | the stereospecificity of the hydrogen removal from reduced pyridine nucleotides catalyzed by nitrate reductase (nadh : nitrate oxidoreductase, ec 1.6.6.1, and nad(p)h : nitrate oxidoreductase, ec 1.6.6.2) was investigated. a high degree of enzyme purification was required to obtain conclusive results. improvements are described for the purification of nitrate reductase from chlorella fusca and from spinach (spinacea oleracea, l.) leaves. the latter enzyme is shown to contain a cytochrome. with h ... | 1977 | 16653 |
| fractionation of inducible alkane hydroxylase activity in pseudomonas putida and characterization of hydroxylase-negative plasmid mutations. | the plasmid-determined inducible alkane hydroxylase of pseudomonas putida resolved into particulate and soluble fractions. spinach reductase and spinach ferredoxin could replace the soluble hydroxylase component. two alkane hydroxylase mutants show in vitro complementation (s. benson and j. shapiro, j. bacteriol., 123: 759-760, 1975): one, alk-7, lacks an active soluble component and the other, alk-181, lacks an active particulate component. together with previous results on a particulate alcoho ... | 1977 | 410794 |
| cf1-dependent restoration of energy-linked reactions reconstituted with a hydrophobic protein from spinach chloroplasts. | 1977 | 142483 | |
| identification of the iron-sulfur center in trimethylamine dehydrogenase. | trimethylamine dehydrogenase [trimethylamine:(acceptor) oxidoreductase (demethylating), ec 1.5.99.7] from a facultative methylotroph bacterium has a molecular weight of 147,000 and contains two types of prosthetic groups, one a covalently bound organic chromophore of uncertain structure and the other containing iron and labile sulfur (s*). the structure of the fe-s* center has been investigated by reactions of the enzyme with sodium mersalyl, o-xylyl-alpha,alpha'-dithiol, and p-methoxybenzenethi ... | 1977 | 265519 |
| preparation and properties of immobilized rubredoxin. | rubredoxin, one of the three protein components of the epoxidation/hydroxylation system of pseudomonas oleovorans was immobilized by attachment to cnbr-activated agarose (sepharose 4b). since this represents the first reported example of the preparation of a water-insoluble derivative of an enzyme of this type, the electron transfer and physical properties of the conjugate were examined in order to allow comparison with those of the soluble enzyme. immobilized rubredoxin exhibits all of the majo ... | 1977 | 849934 |
| membranous modifications in sieve element plasids of spinach affected by the aster yellows disease. | 1977 | 850301 | |
| effects of oxalic acid on availability of zinc from spinach leaves and zinc sulfate to rats. | some effects of dietary oxalic acid on availability of zinc from organic and inorganic sources were assessed. male rats fed zinc-deficient diets with and without added sodium oxalate were orally dosed once with either 65zn-labeled spinach leaves or 65zn-labeled zinc sulfate. spinach plants (spinacia oleracea, var. "winter bloomsdale") were grown in 65zn-labeled nutrient solutions that contained 0.033, 0.131 or 0.262 ppm zinc. increasing zinc supply to the plants increased zinc concentration in t ... | 1977 | 864521 |
| the low temperature magnetic circular dichroism spectra of iron-sulphur proteins. ii. two-iron ferredoxins. | variable temperature magnetic circular dichroism (mcd) spectra of a number of two-iron ferredoxins have been measured. the spectra of fully oxidised spinach and spirulina maxima ferredoxin are independent of temperature between room temperature and 18 k, showing that no contribution to the room temperature mcd spectrum arises from the small population of low-lying excited states originating from the exchange coupling. however, the low temperature mcd spectra of the half-reduced proteins spinach ... | 1977 | 880310 |
| solubility properties of fraction i proteins of maize, cotton, spinach, and tobacco. | 1977 | 881498 | |
| formation in vivo of volatile n-nitrosamines in man after ingestion of cooked bacon and spinach. | 1977 | 558518 | |
| partial analysis of the bands seen in circular dichroism spectra of green and blue-green algal cells and thylakoids. | a comparison was made of the circular dichroism (c.d.) spectra of chlorella, euglena, and anacystis cells and thylakoids. analyses of the spectra reveal that these c.d. bands are similar to those observed previously in whole spinach choloroplasts and subchloroplast particles. c.d. spectra of euglena chloroplasts show bands at longer wavelengths than previously reported. from comparisons of circular dichroism spectra and fine structure, it was concluded that: (a) bands seen in circular dichroism ... | 1977 | 16659816 |
| role of orthophosphate and other factors in the regulation of starch formation in leaves and isolated chloroplasts. | starch synthesis in leaves was increased by phosphate starvation or by treatments which decreased cytoplasmic orthophosphate levels (such as mannose feeding). usually less than 30% of the total carbon fixed during co(2) assimilation was incorporated into starch in spinach (spinacia oleracea l.), spinach beet (beta vulgaris), and tobacco (nicotiana tabacum) leaves.in isolated spinach chloroplasts, formation of starch from co(2) was usually less than in leaves. in the absence of significant levels ... | 1977 | 16660011 |
| strong binding of cytochrome c on the envelope of spinach chloroplasts. | yeast cationic ferricytochrome c was able to bind to the spinach (spinacia oleracea) chloroplast envelope with a low affinity (kd = 1.1 mum). the total amount of low affinity binding sites was of the order of 50 nmol cytochrome c mg(-1) protein. we gave the evidence that binding of ferricytochrome c to the envelope was electrostatic and that the envelope membranes were strongly negatively charged. addition of yeast ferricytochrome c to a preparation of intact washed chloroplasts (class i) induce ... | 1977 | 16660017 |
| uptake and utilization of sugar phosphates by anabaena flos-aquae. | the effect of various sugar phosphates on co(2) fixation in anabaena flos-aquae was investigated and found to be very similar to that found for isolated spinach chloroplasts. one exception, glucose 6-phosphate, has a stimulatory effect on co(2) fixation in anabaena but not in isolated chloroplasts.further examination of the role of glucose 6-phosphate metabolism in anabaena indicates that: (a) this sugar phosphate can be taken up; (b) its uptake is greater in the light than the dark; (c) turnove ... | 1977 | 16660103 |
| mn2+-dependent atpase of the envelope of spinach chloroplasts. | 1977 | 235459 | |
| shuttles of artificial electron donors for photosystem i across the thylakoid membrane. | nadp+ reduction in isolated chloroplasts of spinach by photosystem i at the expense of various artificial donor systems is not inhibited by the plastoquinome antagonist dibromothymoquinone. the coupled atp formation in such photoreductions is attributed to an artificial energy conserving site, i. e. a proton liberation during oxidation of the donor at the inner surface of the thylakoid membrane. some donor systems for photosystem i are stimulated by uncouplers whereas others are not. the stimula ... | 1977 | 235177 |
| [thermal inactivation and storage behavior of technologically important enzymes. i. horseradish and spinach peroxidase]. | the thermal inactivation and storage behaviour for horseradish and spinach peroxidases were investigated in defined systems, in spinach also within its natural environment. the inactivation curves of either enzyme show a sharp bend which is clearly visible at low, but not at higher temperatures. the d-values were taken from the inactivation curves. z-values resulting from the d-values were 25.5 degrees c for horseradish peroxidase, 13 degrees c for isolated peroxidase and 18 degrees c for peroxi ... | 1977 | 19887 |
| chloroplast phosphofructokinase: i. proof of phosphofructokinase activity in chloroplasts. | ammonium sulfate fractionation of an extract from the leaves of spinach (spinacia oleracea l.) produced two fractions of phosphofructokinase activity, the first stimulated by inorganic phosphate and the second inhibited by inorganic phosphate. only the second fraction was obtained from similar treatment of an extract of isolated spinach chloroplasts. the two fractions differed distinctly with respect to kinetics for the substrate fructose 6-phosphate. evidence for these two types of phosphofruct ... | 1977 | 16660078 |
| the lignin fraction of plant cell walls. | methods are discussed for determining lignin in plant cell walls. the increase in apparent lignin content that may occur as a result of artifacts produced during food preparation is also discussed. the phenolic components, including lignin, of cell walls separated from 12 vegetable, fruit, and cereal foods are determined. wheat bran, on a fresh weight basis, had a high cell wall content (48.6%) compared with the vegetables and fruit whose contents ranged from 1.0 to 6.0%. wheat bran and spinach ... | 1978 | 707399 |
| nucleotide sequence of cdna for the cytosolic cu/zn-superoxide dismutase from spinach (spinacia oleracea l.). | 1978 | 2395656 | |
| subcellular distribution of steryl ester biosynthesis in spinach leaves. | higher steryl ester biosynthetic activities were obtained with triton x-100-phosphatidylcholine-cholesterol mixed micelles than with tween 80-phosphatidylcholine-cholesterol mixed micelles when incubated with spinach leaf (spinacia oleracea l.) acetone powder preparations. the best incorporation of [4-(14)c]cholesterol into [4-(14)c]cholesteryl ester was obtained with a triton x-100-phosphatidylcholine-cholesterol (10:1:1, w/w) mixed micelle system. this mixed micelle system, however, required 1 ... | 1978 | 16660292 |
| carbon isotope fractionation by ribulose-1,5-bisophosphate carboxylase from various organisms. | carbon isotope fractionation by structurally and catalytically distinct ribulose-1,5-bisphosphate carboxylases from one eucaryotic and four procaryotic organisms has been measured under nitrogen. the average fractionation for 40 experiments was -34.1 per thousand with respect to the delta(13)c of the dissolved co(2) used, although average fractionations for each enzyme varied slightly: spinach carboxylase, -36.5 per thousand; hydrogenomonas eutropha, -38.7 per thousand; agmenellum quadruplicatum ... | 1978 | 16660363 |
| biosynthesis of ribulose-1,5-bisphosphate carboxylase in spinach leaf protoplasts. | spinach leaf (spinacia oleracea l. var. kyoho) protoplasts sustain protein-synthesizing activity as measured by the incorporation of [(14)c]-leucine into the protein fraction both in the light and in the dark. by the immunoprecipitation of ribulose-1,5-bisphosphate (rup(2)) carboxylase with rabbit antibody raised against the purified spinach enzyme preparation, it was found that approximately 7% of the total radiocarbon incorporated into the protein fraction in the light was in the carboxylase m ... | 1978 | 16660478 |
| preparation and characterization of phospholipid-depleted chloroplasts. | spinach class ii chloroplasts were treated with snake venom phospholipase a2 in the presence of bovine serum albumin, and separated by sucrose-density centrifugation. the treatment yielded phospholipid-depleted chloroplasts which had lost 82.6% of the original phospholipids. about 20% of the phospholipids of chloroplasts were resistant to enzyme attack. these results suggest that phospholipids exist in two states in chloroplast membranes. in spite of considerable phospholipid depletion, the chlo ... | 1978 | 638136 |
| isolation of phosphoglycerate kinases by affinity chromatography. | a variety of sepharose derivatives containing dl-o-phosphorylserine or adenosine nucleotides with different points of attachment, has been synthesized and tested for affinity to phosphoglycerate kinase. the most effective gels contained periodate-oxidized atp or adp bound via the ribose by hydrazone formation to adipoyl-dihydrazo-sepharose. the effect of ph, magnesium and buffer ions on the binding capacity of the atp derivative of sepharose has been examined. optimal elution of phosphoglycerate ... | 1978 | 648532 |
| the intake of nitrate, nitrite and volatile n-nitrosamines and the occurrence of volatile n-nitrosamines in human urine and veal calves. | a hundred samples of total diets, 19 samples of cheese (mainly dutch), a total of 30 samples of muscle, fat liver, kidney, blood and fried meat from experimental veal calves (fed daily with 0.6 or 300 mg of potassium nitrate per kg b.w.) and 14 samples of urine of patients medicated with massive amounts of ammonium nitrate (up to an equivalent of 180 mg potassium nitrate per kg b.w.) have been analysed with gc-tea for their content of the following n-nitrosamines: ndma, ndea, ndpa, ndba, npip, n ... | 1978 | 680737 |
| adsorption of bile salts from aqueous solution by plant fibre and cholestyramine. | 1. adsorption of bile salts by dietary fibre is believed to promote their excretion and hence to reduce the serum cholesterol level in man and experimental animals. 2. we have tested a number of plant fibre fractions and other related materials for their ability to adsorb bile salts from aqueous solution. the "insoluble" plant fractions were from "dry grain" (a residue from brewing), apple, wheat bran, lucerne (medicago sativa), soya beans, mung beans (phaseolus mungo), chick peas (cicer arieti ... | 1978 | 698168 |
| inactivation of ribulosebisphosphate carboxylase by modification of arginyl residues with phenylglyoxal. | phenylglyoxal rapidly and completely inactivates spinach and rhodospirillum rubrum ribulosebisphosphate carboxylases. inactivation exhibits pseudo-first-order kinetics and a reaction order of approximately one for both enzymes, suggesting that modification of a single residue per protomeric unit suffices for inactivation. loss of enzymic activity is directly proportional to incorporation of [14c]phenylglyoxal until only 30% of the initial activity remains. for both enzymes, extrapolation of inco ... | 1978 | 728421 |
| low-molecular-weight (4.5s) ribonucleic acid in higher-plant chloroplast ribosomes. | a species of rna that migrates on 10% (w/v) polyacrylamide gels between 5s and 4s rna was detected in spinach chloroplasts. this rna (referred to as 4.5 s rna) was present in amounts equimolar to the 5s rna and its molecular weight was estimated to be approx. 33 000. fractionation of the chloroplast components showed that the 4.5s rna was associated with the 50 s ribosomal subunit and that it could be removed by washing the ribosomes with a buffer containing 0.01 m-edta and 0.5 m-kcl. it did not ... | 1978 | 743229 |
| evidence for a catalytic function of the coupling factor 1 protein reconstituted with chloroplast thylakoid membranes. | the effects of tentoxin on the atpase activities of coupling factor 1 proteins (cf1) and photophosphorylation with isolated chloroplasts and chloroplasts reconstituted with coupling factor proteins have been examined. 1. the calcium-dependent atpase activities of coupling factors isolated from spinach, lettuce and nicotiana otophora are completely inhibited by tentoxin. the atpase activities of coupling factors isolated from nicotiana tabacum and nicotiana knightiana are not affected by tentoxin ... | 1978 | 147703 |
| analyses of absorption and fluorescence spectra of water-soluble chlorophyll proteins, pigment system ii particles and chlorophyll a in diethylether solution by the curve-fitting method. | absorption and fluorescence spectra in the red region of water-soluble chlorophyll proteins, lepidium cp661, cp663 and brassica cp673, pigment system ii particles of spinach chloroplasts and chlorophyll a in diethylether solution at 25 degrees c were analyzed by the curve-fitting method (french, c.s., brown, j.s. and lawrence, m.c. (1972) plant physiol 49, 421--429). it was found that each of the chlorophyll forms of the chlorophyll proteins and the pigment system ii particles had a correspondin ... | 1978 | 96855 |
| isolation and characterisation of 14-s rna from spinach chloroplasts. | 14-s rna was purified from spinach chloroplasts. it has a molecular weight of 0.43 . 10(6) and the following nucleotide composition: 20% cmp, 23.9% amp, 24.2% gmp and 31.9% ump. the accumulation of 14-s rna in chloroplasts of cotyledons of dark-grown plants is stimulated by light. conditions are described for the isolation of 14-s rna in the absence of appreciable fragmentation of chloroplast 23-s rrna and the evidence that it represents a distinct type of chloroplast rna is discussed. translati ... | 1978 | 367438 |
| purification and some properties of riboflavin synthetase from bacillus stearothermophilus atcc 8005. | a riboflavin synthetase was purified 51-fold from a thermophilic organism, bacillus stearothermophilus atcc 8005, that grew at 40 to 72 degrees c. some of the properties of the enzyme are: (i) its temperature optimum was 95 degrees c, and the activity was negligible below 40 degrees c; (ii) the arrhenius plot of the initial reaction rates was concave upward, with a break at 65 degrees c, and the apparent activation energies below and above 65 degrees c were 4.2 x 10(4) and 6.7 x 10(4) j/mol, res ... | 1978 | 25043 |
| the role of chloride ion in photosystem ii. i. effects of chloride ion on photosystem ii electron transport and on hydroxylamine inhibition. | 1. chloroplasts washed with cl--free, low-salt media (ph 8) containing edta, show virtually no dcmu-insensitive silicomolybdate reduction. the activity is readily restored when 10 mm cl- is added to the reaction mixture. very similar results were obtained with the other photosystem ii electron acceptor 2,5-dimethylquinone (with dibromothymoquinone), with the photosystem i electron acceptor fmn, and also with ferricyanide which accepts electrons from both photosystems. 2. strong cl--dependence of ... | 1978 | 26390 |
| enzyme reactions of atp studied by positional isotope exchange. | reversible gamma-po3 transfer in atp reactions can be recognized by exchange of 18o from the beta,gamma-bridge position to the beta-p-nonbridge positions: (see article). such intramolecular exchange is less demanding for the detection of the bond cleavage than the usual atp:adp isotope exchange because it does not require dissociation of bound adp from the intermediate complex. acyl phosphate intermediates are indicated for the glutamine synthetase and carbamyl-p synthetase reactions by their ex ... | 1978 | 31305 |
| crystalline reduced nicotinamide adenine dinucleotide phosphate-adrenodoxin reductase from pig adrenocortical mitochondria. essential histidyl and cysteinyl residues of the nadph-binding site and environment of the adrenodoxin-binding site. | pig nadph-adrenodoxin reductase was crystallized from pig adrenocortical mitochondria and its physicochemical properties were investigated. pig nadph-adrenodoxin reductase is a typical flavoprotein. its optical absorption spectrum showed peaks at 272, 377, and 450 nm in the oxidized form. the adrenodoxin reductase contained one fad per mol. the molecular weight was 49,000. the isoelectric points of the adrenodoxin reductase and its complex with adrenodoxin were 5.3 and 4.6, respectively. pig nad ... | 1978 | 32168 |
| electron spin polarization in photosynthesis and the mechanism of electron transfer in photosystem i. experimental observations. | transient electron paramagnetic resonance (epr) methods are used to examine the spin populations of the light-induced radicals produced in spinach chloroplasts, photosystem i particles, and chlorella pyrenoidosa. we observe both emission and enhanced absorption within the hyperfine structure of the epr spectrum of p700+, the photooxidized reaction-center chlorophyll radical (signal i). by using flow gradients or magnetic fields to orient the chloroplasts in the zeeman field, we are able to influ ... | 1978 | 204369 |
| phosphoglycolate phosphatase. purification and properties. | phosphoglycolate phosphatase (ec 3.1.3.18) was purified 1500-fold from field-grown tobacco leaves by acetone fractionation, deae-cellulose and molecular sieve chromatography, and preparative polyacrylamide gel electrophoresis. preparations were judged 90 to 95% homogeneous by chromatography on deae-cellulose, polyacrylamide gel electrophoresis, and by isoelectric focusing. the highest specific activity obtained was 468 mumol of phosphate released/min/mg of protein. the native protein has a molec ... | 1978 | 204630 |
| multiple functions of thioredoxins. | reduced thioredoxins from microbial and plant cells, both of cytoplasmic or chloroplast origin, are interchangeable in stimulating such diverse enzyme activities as ribonucleoside diphosphate reductase (e. coli), paps sulfotransferase (synechococcus), and fructose-1,6-bis-phosphatase (from spinach) in vitro. it is suggested that reduced thioredoxins are unspecific, multifunctional cellular proteins while in contrast the oxidized froms require specific enzymes for their reduction. | 1978 | 212888 |
| regulation of chloroplast photosynthetic activity by exogenous magnesium. | magnesium was most inhibitory to photosynthetic reactions by intact chloroplasts when the magnesium was added in the dark before illumination. two millimolar mgcl(2), added in the dark, inhibited co(2)-dependent o(2) evolution by hordeum vulgare l. and spinacia oleracea l. (c(3) plants) chloroplasts 70 to 100% and inhibited (pyruvate + oxaloacetate)-dependent o(2) evolution by digitaria sanguinalis l. (c(4) plant) mesophyll chloroplasts from 80 to 100%. when mg(2+) was added in the light, o(2) e ... | 1978 | 16660509 |
| [review on nonessential constituents of vegetables. iii. carrots, celery, parsnips, beets, spinach, lettuce, endives, chicory, rhubarb, and artichokes (author's transl)]. | 1978 | 716640 | |
| fixation of o(2) during photorespiration: kinetic and steady-state studies of the photorespiratory carbon oxidation cycle with intact leaves and isolated chloroplasts of c(3) plants. | mass spectrometric techniques were used to trace the incorporation of [(18)o]oxygen into metabolites of the photorespiratory pathway. glycolate, glycine, and serine extracted from leaves of the c(3) plants, spinacia oleracea l., atriplex hastata, and helianthus annuus which had been exposed to [(18)o]oxygen at the co(2) compensation point were heavily labeled with (18)o. in each case one, and only one of the carboxyl oxygens was labeled. the abundance of (18)o in this oxygen of glycolate reached ... | 1978 | 16660647 |
| 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 |
| effect of high cation concentrations on photosystem ii activities. | the effects of wide concentration ranges of nacl, kcl, and mgcl(2) on ferricyanide reduction and the fluorescence induction curve of isolated spinach (spinacia oleracea) chloroplasts were investigated. concentrations of the monovalent salts above 100 mm and mgcl(2) above 25 mm produced a decrease in the rate of ferricyanide reduction by thylakoids uncoupled with 2.5 mm nh(4)cl which cannot be attributed to changes in the primary photochemical capacity of photosystem ii. salt-induced decreases in ... | 1978 | 16660632 |
| studies on cation-induced thylakoid membrane stacking, fluorescence yield, and photochemical efficiency. | trypsin digestion of photosynthetic membranes isolated from spinach (spinacia oleracea l.) leaves eliminates the cation stimulation of chlorophyll fluorescence. high concentrations of cations protect the fluorescence yield against trypsin digestion, and the cation specificity for this protection closely resembles that required for the stimulation of fluorescence by cations. trypsin digestion reverses cation-induced thylakoid stacking, and the time course of this effect seems to parallel that of ... | 1978 | 16660630 |
| the accumulation of neutral red in illuminated thylakoids. | thylakoids isolated from spinach (spinacia oleracea l.) bind only a small fraction of neutral red in the dark whereas they accumulate large amounts of the protonated dye in their inner space under light. light-induced neutral red uptake depends on the size of the proton gradient across the thylakoid membrane but does not follow the mechanism established for amines. instead, the correlation between ph gradient and neutral red uptake can be predicted quantitatively assuming that protonated neutral ... | 1978 | 718876 |
| freeze-thaw injury to isolated spinach protoplasts and its simulation at above freezing temperatures. | possibilities to account for the mechanism of freeze-thaw injury to isolated protoplasts of spinacia oleracea l. cv. winter bloomsdale were investigated. a freeze-thaw cycle to -3.9 c resulted in 80% lysis of the protoplasts. at -3.9 c, protoplasts are exposed to the equivalent of a 2.1 osmolal solution. isolated protoplasts behave as ideal osmometers in the range of concentrations tested (0.35 to 2.75 osmolal), arguing against a minimum critical volume as a mechanism of injury. average protopla ... | 1978 | 16660588 |
| diurnal oscillation of amylolytic activity in spinach chloroplasts. | chloroplasts isolated from spinach (spinacia oleracea l., cv. vital(r)) plants grown under controlled light/dark and temperature regimes, contained the phosphorolytic and amylolytic pathways for starch breakdown. the latter consists at least of alpha- and beta-amylase and maltase. only low amylolytic activity was observed in chloroplasts isolated during the light phase. in chloroplasts prepared during the dark phase, this activity was almost twice as high. these diurnal oscillations of the amylo ... | 1978 | 16660584 |
| chemical cross-linking of neighboring thylakoid membrane polypeptides. | cross-linking between protein components of whole spinach (spinacia oleracea var. nobel) thylakoids and of photosystem i- and ii-enriched thylakoid fractions has been produced by reaction with the bifunctional imidoester dimethyl-3,3'-dithiobispropionimidate dihydrochloride as well as by the oxidation of intrinsic sulfydryl groups with an orthophenanthrolinecupric ion complex. the mixture of membrane proteins and their cross-linked products has been analyzed by two-dimensional sodium dodecyl sul ... | 1978 | 16660519 |
| identification of an acyl donor in steryl ester biosynthesis by enzyme preparations from spinach leaves. | a pathway for steryl ester biosynthesis in acetone powder preparations from spinach (spinacia oleracea l.) leaves has been elucidated; free sterol and 1,2-diglyceride were the substrates. although animals synthesize cholesteryl esters by three distinct biosynthetic pathways, none of these pathways utilizes 1,2-diglyceride as an acyl donor. phosphatidylcholine, phosphatidic acid, triglyceride, 1,3-diglyceride, 1-monoglyceride, free fatty acid, and fatty acyl-coa were not acyl donors for spinach l ... | 1978 | 16660515 |
| malate and dihydroxyacetone phosphate-dependent nitrate reduction in spinach leaf protoplasts. | isolated spinach (spinacia oleracea l. var. bloomsdale) leaf protoplasts reduced nitrate at rates of 9 micromoles per milligram chlorophyll per hour in light with a 3- to 4-fold stimulation in the presence of hco(3) (-). a similar stimulation of nitrate reduction in the absence of co(2) fixation was obtained by the addition of malate, oxaloacetate (oaa), phospho-3-glyceric acid (pga), or dihydroxyacetone phosphate (dhap). stimulation by malate and dhap was light-independent, while the pga and oa ... | 1978 | 16660489 |
| comparison of photosynthetic activities of spinach chloroplasts with those of corn mesophyll and corn bundle sheath tissue. | bundle sheath and mesophyll chloroplasts from zea mays showed comparable rates of o(2) evolution, which amounted to about half of the rate observed in spinach (spinacia oleracea) chloroplasts.ratios of 4.5, 4.6, and 6.2 mn(2+) atoms per 400 chlorophylls were observed in mesophyll, bundle sheath, and spinach chloroplasts, respectively. these ratios roughly correspond to the observed o(2) evolution rates.rates of electron transport from water to methylviologen (photosystem i and ii) in both types ... | 1978 | 16660469 |
| effects of inhibitors of catalase on photosynthesis and on catalase activity in unwashed preparations of intact chloroplasts. | the catalase activity of unwashed preparations containing intact spinach (spinacia oleracea l.) chloroplasts is inhibited both by cyanide and by azide at concentrations which also cause inhibition of photosynthetic co(2)- dependent o(2) evolution.aminotriazole can also be used to inhibit this contaminant catalase, and in this case inhibition of catalase can be achieved at aminotriazole concentrations which have little effect on the rate of photosynthetic co(2) fixation. aminotriazole may be used ... | 1978 | 16660434 |
| activation of chloroplast nadp-linked glyceraldehyde-3-phosphate dehydrogenase by the ferredoxin/thioredoxin system. | nadp-glyceraldehyde-3-p dehydrogenase of spinach (spinacia oleracea) chloroplasts was activated by thioredoxin that was reduced either photochemically with ferredoxin and ferredoxin-thioredoxin reductase or chemically with dithiothreitol. the activation process that was observed with the soluble protein fraction from chloroplasts and with the purified regulatory form of the enzyme was slow relative to the rate of catalysis. the nad-linked glyceraldehyde-3-p dehydrogenase activity that is also pr ... | 1978 | 16660360 |
| light-induced changes of the carotenoid levels in chloroplast envelopes. | the carotenoid content of thylakoids and envelopes isolated from dark-or light-treated spinach (spinacia oleracea l.) chloroplasts was compared. in thylakoids, light induced a decrease of violaxanthin parallel with a stoichiometric increase of zeaxanthin due to violaxanthin deepoxidation. in envelopes, violaxanthin was also decreased and the relative decrease was similar to thylakoids, but zeaxanthin increase was small resulting in an over-all decrease of the amount of envelope carotenoids. when ... | 1978 | 16660330 |
| free flow electrophoresis of chloroplasts. | highly purified intact chloroplasts were isolated from spinach (spinacia oleracea l.) leaves by free flow electrophoresis. morphological and biochemical studies showed that the fraction enriched in intact chloroplasts has a higher protein to chlorophyll ratio and a higher linolenic acid content than the broken organelles of the other fraction. the intact chloroplasts prepared by electrophoresis retained their capacity for co(2) fixation. sodium dodecyl sulfate polyacrylamide gel electrophoresis ... | 1978 | 16660315 |
| low temperature spectral properties of subchloroplast fractions purified from spinach. | spinach (spinacia oleracea l.) chloroplasts solubilized by digitonin were separated into five fractions by sucrose density gradient centrifugation. three of the fractions, f(i), f(ii), and f(iii), corresponding to photosystem i, photosystem ii, and the chlorophyll a/b complex, were purified further by two steps of diethylaminoethyl-cellulose chromatography followed by electrofocusing on an ampholine column. the polypeptide patterns of the fractions were examined by sodium dodecyl sulfate-polyacr ... | 1978 | 16660296 |
| partial characterization of steryl ester biosynthesis in spinach leaves. | acetone powders of a 20,000g pellet fraction from spinach leaves (spinacia oleracea l.) synthesized [4-(14)c]cholesteryl esters when incubated with [4-(14)c]cholesterol. the reaction was inhibited by digitonin. there was a reciprocal relationship between the decline of label in cholesterol and its incorporation into cholesteryl ester, indicating that free cholesterol was the direct precursor for cholesteryl ester biosynthesis. the hydrolysis of cholesteryl [1-(14)c]palmitate into free cholestero ... | 1978 | 16660291 |
| cytokinins in trna obtained from spinacia oleracea l. leaves and isolated chloroplasts. | cytokinin-active ribonucleosides have been isolated from trna of whole spinach (spinacia oleracea l.) leaves and isolated spinach chloroplasts. the trna from spinach leaf blades contained: 6-(4-hydroxy-3-methyl-2-butenylamino)-9-beta-d-ribofuranosylpurine (cis and trans isomers), 6-(3-methyl-2-butenylamino)-9-beta-d-ribofuranosylpurine, and 6-(4-hydroxy-3-methyl-2-butenylamino)-2-methylthio-9-beta-d -ribofuranosylpurine (cis and trans isomers). a method for isolation of large amounts of intact c ... | 1978 | 16660279 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| linoleate and alpha-linolenate synthesis by isolated spinach (spinacia oleracea) chloroplasts. | diacylgalactosylglycerol synthesis was a prerequisite for the incorporation of [1-14c]-acetate into linoleate and alpha-linolenate of isolated spinach (spinacia oleracea) chloroplasts. oleate at position 1 of diacylgalactosylglycerol was desaturated to linoleate and alpha-linolenate both in the light and in the dark. some desaturation of palmitate was also observed after prolonged incubations. | 1979 | 540049 |
| stoichiometry of carbon dioxide release and oxygen uptake during glycine oxidation in mitochondria isolated from spinach (spinacia oleracea) leaves. | mitochondria isolated from spinach (spinacia oleracea) leaves oxidized glycine with a stoichiometry of co2 evolution to o2 uptake of 2 : 1. in the absence of added substrate, the mitochondria exhibited an extremely low endogenous rate of o2 uptake. | 1979 | 534540 |
| on the mechanism of activation by light of the nadp-dependent malate dehydrogenase in spinach chloroplasts. | with intact spinach (spinacia oleracea l. cv. vital r) chloroplasts, the activity of the nadp-dependent malate dehydrogenase after activation by light was 30 micromoles of malate formed per milligram of chlorophyll per hour; an identical rate of o(2) evolution was obtained upon oxaloacetate reduction by the intact plastids. however, when the activity of nadp-dependent malate dehydrogenase was measured subsequently to maximal activation of the enzyme by dithiothreitol (dtt) an average rate of 113 ... | 1979 | 16661046 |
| intracellular localization of beta-aspartate kinase in spinach (spinacea oleracea). | 1979 | 225209 | |
| proline oxidase and water stress-induced proline accumulation in spinach leaves. | spinach (spinacia oleracea l.) leaf discs accumulated free proline when exposed to polyethylene glycol solutions of water potential less than -10 bars. at -20 bars, the accumulation was 11 micromoles per gram original fresh weight in a 24-hour period.when the leaf organelles were separated on a sucrose gradient, a proline oxidase was detected in the mitochondrial fraction. isolated mitochondria were used for the study of the properties of the enzyme which was assayed by both oxygen uptake measur ... | 1979 | 16660761 |
| 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 |
| 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 |