Showing papers in "Plant and Cell Physiology in 1989"

Ascorbate Peroxidase in Tea Leaves: Occurrence of Two Isozymes and the Differences in Their Enzymatic and Molecular Properties

Abstract: Two isozymes of ascorbate (AsA) peroxidase were found in tea leaves, and one of them (AsA peroxidase II) was purified to homogeneity, as judged by polyacrylamide gel electrophoresis. AsA peroxidase II is a monomer with a molecular weight of 34,000 and contains protoheme, but it is not a glycoprotein. The enzyme showed a Soret peak at 409 nm and at 420 nm when oxidized and reduced, respectively, with an a-band at 556 nm. The oxidized enzyme showed two small peaks at 478 nm and 530 nm

Carbohydrate Metabolism in the Developing Endosperm of Rice Grains

Abstract: Etude du metabolisme des hydrates de carbone dans l'albumen de grains de riz (Oryza sativa) en developpement par comparaison des taux d'activite de 33 enzymes majeures entre l'albumen et les feuilles vertes. Les taux de metabolites intermediaires et la localisation des enzymes cle du metabolisme du saccharose et de l'amidon ont ete etudies dans des amyloplastes de grains de riz en developpement, et ont permis de caracteriser la voie de synthese de l'amidon a partir du saccharose

Synechocystis PCC6803 Mutants Defective in Desaturation of Fatty Acids

Abstract: Two mutants, which were defective in desaturation of fatty acids, were isolated from the cyanobacterium, Synechocystis PCC6803, by treating wild-type cells with ethyl methanesulfonate. They were designated as Fad6 and Fad12. Fad6 was defective in desaturation at the Δ 6 position of C 18 fatty acids esterified to the sn-1 position of glycerol moiety in monogalactosyl diacylglycerol and digalactosyl diacylglycerol but not sulfoquinovosyl diacylglycerol and phosphatidylglycerol. Fad12 was defective in desaturation at the Δ 12 position of C 18 fatty acids at the sn-1 position of glycerol moiety in all the lipid classes

Presence of a Na+-activated ATPase in the Plasma Membrane of the Marine Raphidophycean Heterosigma akashiwo

Abstract: Isolement de membranes plasmiques hautement purifiees et d'une ATPase membranaire activee par les ions sodium dans les cellules de Heterosigma akashiwo. Deux formes intermediaires de l'ATPase sont detectees. La premiere forme est phosphorylee en presence d'ions sodium et magnesium et la seconde en presence d'ions magnesium uniquement. La signification physiologique de ces 2 sortes d'ATPases dans la membrane plasmique de cette algue marine est discutee

Quantitative Analysis of Endogenous Gibberellins in Normal and Dwarf Cultivars of Rice

Abstract: Identification et quantification de GA 1 , GA 4 , GA 19 et GA 20 qui sont des gibberellines cles dans la regulation de la croissance du riz

Variations in the Natural Abundance of 15N in Nitrogenous Fractions of Komatsuna Plants Supplied with Nitrate

Abstract: Mesure des variations du δ15N dans les nitrates, aminoacides et fractions azotees residuelles des tissus de Brassica campestris var. rapa se developpant sur des milieux de concentrations en nitrate variables

Cell-Specific Expression of the rolC Gene of the TL-DNA of Ri Plasmid in Transgenic Tobacco Plants :

Abstract: Transgenic tobacco plants possessing a chimeric gene of the promoter region of the Ri plasmid ORF12 gene (rolC) and a structural gene of bacterial β-glycuronidase were obtained

Comparison of Extracellular Polysaccharide Composition, Rhizobitoxine Production, and Hydrogenase Phenotype among Various Strains of Bradyrhizobium japonicum

Abstract: A survey of 51 strains of Bradyrhizobium japonicum was performed with respect to the composition of extracellular polysaccharide (EPS), the production of rhizobitoxine and the hydrogenase phenotype. A good correlation was found among these three different characteristics. Thirty-six strains producing an EPS composed of glucose, mannose, galactose, 4-O-methyl galactose and galacturonic acid did not synthesize rhizobitoxine, whereas 14 strains producing an EPS composed of rhamnose and 4-O-methyl glucuronic acid were all found to synthesize rhizobitoxine. Hydrogen-uptake positive (Hup + ) strains were confined exclusively to the former group of strains which produced an EPS composed of glucose, mannose, galactose, 4-O-methyl galactose and galacturonic acid. These results suggest that the phenotype with respect to rhizobitoxine production and hydrogen uptake is involved in the phylogeny of Bradyrhizobium japonicum as well as in the productivity of nodulated soybeans.

Supramolecular Assembly and Function of Subunits Associated with the Chlorophyll a-b Light-Harvesting Complex II (LHC II) in Soybean Chloroplasts

Abstract: Utilisation de mutants pauvre et deficient en chlorophylle b ainsi que du type sauvage afin de determiner le nombre de complexes collecteurs de lumiere par unite PS II et le nombre de molecules de chlorophylle par complexe collecteur de lumiere

Topological Considerations of the 9-kDa Polypeptide which Contains Centers A and B, Associated with the 14- and 19-kDa Polypeptides in the Photosystem I Complex of Spinach

Abstract: Etude de la topographie du polypeptide de 9 KDa du PSI de l'epinard par des traitements avec des ions alcalins et chaotropiques, par digestions tryptiques et liaisons croisees d'anticorps diriges contre les polypeptides de 9, 14 et 19 KDa de la membrane des thylakoides. Le modele topologique presente ici est en desaccord avec celui presente par Munch et al. en 1988

Stabilization of Soluble Proteins in Vitro by Heat Shock Proteins-Enriched Ammonium Sulfate Fraction from Soybean Seedlings

Abstract: The 70-100% ammonium sulfate fraction of postribosomal supernatant of heat shocked soybean seedlings contained a high percentage of all of the heat shock proteins. The proteins in this fraction were resistant to heat denaturation, as judged by their unpelletability after heat treatment. Moreover, this fraction, when added to the postribosomal supernatant from control (nonheat shocked) seedlings, showed a significant ability to protect the control proteins from heat denaturation. Heated at 55°C, some 50% of the control proteins, which were normally denatured after heat treatment, were protected for at least 1 h when heat shock proteins-enriched fraction was added. The degree of protection was proportional to the amount of heat shock proteins-enriched fraction added. However, when the ammonium sulfate fraction prepared from the seedlings with a heat treatment at 40° C for 3 h followed with a brief heat shock at 45 °C which depleted most of the 15-18 kDa and partial 68-70 kDa, 24 kDa and 22 kDa heat shock proteins was added the effectiveness in preventing heat denaturation was lost. This suggests that the heat shock proteins of 15-18 kDa with those of 68-70 kDa and perhaps 24 kDa and 22 kDa are important for providing the protection from heat denaturation.

Glyoxylate Inhibition of Ribulosebisphosphate Carboxylase/Oxygenase Activation State in vivo :

Abstract: Mesure des taux de ribulosebisphosphate foliaire et de photosynthese afin d'evaluer l'hypothese qu'une diminution en intermediaires du cycle de Calvin induit une rapide inhibition de la photosynthese chez des mutants d'Arabidopsis thaliana pour la photorespiration. Etude in vivo et in vitro de la rubisco

Lipids of Chlamydomonas reinhardtii. Incorporation of [14C]Acetate, [14C]Palmitate and [14C]Oleate into Different Lipids and Evidence for Lipid-Linked Desaturation of Fatty Acids

Abstract: The lipids of Chlamydomonas reinhardtii mainly consist of MGDG, DGDG, SQDG, PG, PE, PI and the betaine lipid DGTS. PC, however, was shown to be strictly absent from this alga (Giroud et al. 1988). The chloroplast lipids are of the prokaryotic, DGTS and PE of the eukaryotic type. Each lipid class is characterized by an individual pattern of molecular species suggesting that fatty acids are desaturated in a lipid-linked process in which the different lipids individually act as substrates for the desaturase(s). In order to provide additional evidence for this process, cells were labelled with 14C-acetate, 14C-palmitate or 14C-oleate and the radioactivity was measured after different times in each lipid class and in their fatty acids and molecular species.

Polyamines and anaerobic elongation of rice coleoptile

Abstract: Description d'une difference dans le metabolisme des polyamines entre des coleoptiles de riz poussant en conditions aerobie et anaerobie. En condition anaerobie, on observe une accumulation de putrescine libre. L'utilisation de putrescine exogene et d'inhibiteurs de la synthese des polyamines a permis de demontrer la necessite de ces substances pour l'elongation des coleoptiles de riz en condition anaerobie

Effects of Leaf Chilling on Thylakoid Functions, Measured at Room Temperature, in Cucumis sativus L. and Oryza sativa L.

Abstract: Le traitement de feuilles de concombre par le froid, a la lumiere et a l'obscurite, est etudie sur les thylakoides isoles. A l'obscurite, la chute de temperature affecte le mecanisme de scission de l'eau dans le PS.2. alors qu'a la lumiere, le froid altere l'ATPase. Dans le cas du riz, les 2 traitements affectent peu les fonctions des thylakoides. Les evolutions de l'oxygene et de la fluorescence ont egalement ete examinees dans des disques de feuilles avant et apres les traitements par le froid, afin de relier des mesures in vivo aux caracteristiques observees in vitro dans les thylakoides

Photosynthetic Determinants of Growth in Maize Plants: Effects of Nitrogen Nutrition on Growth, Carbon Fixation and Photochemical Features

Abstract: Photosynthetic characteristics of mature maize leaves that may be determinants of plant growth. Nitrogen supply was varied to manipulate growth. Specific objectives were to determine whether biomass production was related to carbon exchange rate and/or export rate and whether carbon exchange rate was related to photosynthetic enzyme levels, triose phosphate utilization and/or photochemical capacity as expressed in the functional organization of the photosynthetic unit