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Methionine can induce more than a 100% increase in ethylene production by apple tissue slices. The increased amount of ethylene derives from carbons 3 and 4 of methionine. Only post-climacteric fruit tissues are stimulated by methionine, and stimulation is optimum after 8 months' storage. Copper chelators such as sodiu... |
Mitochondrial fractions isolated from pears (Pyrus communis L.) at the climacteric minimum and peak were subjected to sucrose density gradient centrifugation. The distribution of protein and specific activities of 3 enzymes from this mitochondrial fraction were investigated.Cytochrome oxidase specific activity remained... |
Experiments were conducted on Nicotiana tabacum, L. to study the relation in the grana among chlorophylls, carotenoids, and proteins. The effect of iron chlorosis on protein and pigment synthesis was studied at different stages of chlorosis using glycine-U-C(14). Pigments were separated by thin layer chromatography.Chl... |
NAD kinase was exclusively found in the soluble portion of the cell components. The enzyme was purified about 100-fold from sucrose extracts of spinach leaves.Plant NAD kinase catalyzes formation of NADP from NAD, ATP, and Mg(++), but scarcely any formation of NADPH from NADH. NADH was a very potent competitive inhibit... |
Four methods for extracting nucleic acids from lyophilized cotton (Gossypium hirsutum L. cv. Stoneville 62) leaves and roots were compared. They were based on the use of: (I) HC10(4); (II) KOH; (III) a mixture of 90% phenol, Tris (hydroxymethyl) aminomethane buffer, and sodium lauryl sulfate; and (IV) NaCl. (I) extract... |
Changes in free space of banana tissue during ripening were measured using radioisotopes. Free space increased significantly about 44 hours before the onset of, and rose exponentially during the respiratory climacteric. The increase in free space indicates a progressive increase in the proportion of cells which becomes... |
The effect of substrate manganese on tissue manganese levels and activity of the indoleacetic acid (IAA)-oxidase system of cotton (Gossypium hirsutum, L.) was investigated. A sand culture technique was used with 1, 3, 9, 27 and 81 mg manganese (MnSO(4)) per liter nutrient solution applied in various experiments.The fol... |
Experiments were designed to determine the significance of dark CO(2) fixation in excised maize roots, carrot slices and excised tomato roots grown in tissue culture. Bicarbonate-(14)C was used to determine the pathway and amounts of CO(2) fixation, while leucine-(14)C was used to estimate protein synthesis in tissues ... |
Isolated chloroplasts from wheat leaves incorporate radioactive amino acids into protein. Both physiological and biochemical evidence show that contaminating bacteria are not responsible for the activity. Activity is best in plastids from 5-day-old or younger seedlings; a sharp drop usually occurs by day 6 or 7. The sy... |
Hardening of SD (8 and 12 hrs) and LD (18- and 24-hr photoperiods) cabbage plants in stages at temperatures starting with + 5 degrees and ending with - 3 degrees led to the following changes:Soluble protein plus nonprotein N showed a net increase only in the SD plants. In both SD and LD plants, it decreased to a minimu... |
Light-induced modifications in lipoxidase metabolism and chlorophyll formation in the cotyledon of squash (Cucurbita moscata) seedlings were determined. The enzyme activity decreased as light intensity increased, but chlorophyll continued to accumulate long after lipoxidase activity had virtually disappeared. Consideri... |
The increase in respiratory activity in germinating peanut cotyledons has been correlated with an actual increase in mitochondria. Using sucrose gradient centrifugation, it was shown that succinoxidase activity is associated with a well-defined band of cell particulates of uniform density, size and ultrastructure. Duri... |
Ginkgo biloba L. pollen-derived tissue, which is made up of small, friable masses of homogeneous parenchymatous cells, was shown to require boron in the culture medium. If no boron is supplied, growth soon stops. Growth responses to additions of boron were observed up to an optimum level of 0.1 mg of boron per liter.Hi... |
The possibility that leaf abscission might involve a mobilization phenomenon leading to a localized cellular senescence was examined by following dry weight changes, chlorophyll content, and protein levels in proximal and distal tissue of excised pieces of bean petioles from Phaseolus vulgaris L. var. Red Kidney. Nucle... |
Tissue cultures of Nicotiana labacum consisting of green, albino and habituated (normal origin) and teratoma (tomorous origin) were grown under asceptic conditions for 6 to 8 weeks and their extracts were analyzed for phosphatase activity. Comparative enzyme analyses were also made on crude stem extracts of greenhouse-... |
The effects of various light intensities on in vivo increases in activities of phosphoriboisomerase, phosphoribulokinase and ribulose-1, 5-diP carboxylase and on synthesis of chlorophyll were studied in greening leaves of Hordeum vulgare L.Each enzyme was already present in dark-grown plants, but further increases in a... |
There was a 6 to 24-hour lag in the production of anthocyanins in the light after excision of 4-day-old etiolated internodes of Sorghum vulgare variety Wheatland milo. In internodes infiltrated with water, apigeninidin was formed first at 12 to 24 hours and continued to be produced slowly. Luteolinidin was formed sligh... |
Greening of leaves of Phaseolus vulgaris in the presence of chloramphenicol inhibits formation of A) total chloroplast protein, B) an easily extractable fraction removed during isolation of chloroplasts in isotonic media by differential centrifugation, and C) the insoluble lamellar fraction which remains after extracti... |
The kinetics of development of protein-synthesizing capacity in the imbibing wheat embryo, were studied both in vivo and in vitro. During the first 30 minutes of imbibition protein-synthesizing capacity rises rapidly, lagging about 10 minutes behind water uptake. This rise in synthesizing capacity is accompanied by an ... |
Freshly cut disks of beetroot tissue develop high rates of respiration, uptake of phosphate and activity of the enzyme invertase after having been washed for 18 hours in 0.01 m potassium maleate.Incubation of the disks in solutions of indole-3-acetic acid or kinetin completely prevented the development of the higher ac... |
Extracts from roots of Nicotiana tabacum L var. Bottom Special contain oxidative enzymes capable of rapid degradation of indoleacetic acid (IAA) in the presence of Mn(2+) and 2, 4-dichlorophenol. Purification of IAA oxidase was attempted by means of ammonium sulfate fractionation and elution through a column of SE-Seph... |
Previous experiments have revealed a much greater efficiency of ammonium utilization by bean plants (Phaseolus vulgaris L.) when the acidity of the ambient medium was maintained at near-neutral conditions with carbonates or hydroxides. The present investigation, in which (15)N-labeled ammonium was used, permitted an as... |
The ability of Arizona Common and Coastal Bermuda grass [Cynodon dactylon (L.) Pers.] to synthesize amino acids and proteins during water stress was investigated. Amino acids were continually synthesized during the water stress treatments, but protein synthesis was inhibited and protein levels decreased.Water stress in... |
Phenylalanine ammonia-lyase activity was investigated in preparations representing various parts of sweetclover (Melilotus alba Desr.) plants of CuCu and cucu genotypes. In contrast to other plant parts, very young leaves and stems of CuCu plants displayed high phenylalanine ammonia-lyase activity. Initial leaf samples... |
Ethylene stimulated RNA and protein synthesis in bean (Phaseolus vulgaris L. var. Red Kidney) abscission zone explants prior to abscission. The effect of ethylene on RNA synthesis and abscission was blocked by actinomycin D. Carbon dioxide, which inhibits the effect of ethylene on abscission, also inhibited the influen... |
The behavior of exogenously supplied alanine, proline, glutamine, glutamic acid and aspartic acid in isotope competition experiments using cells of Paul's Scarlet Rose grown in the presence of glucose-U-(14)C was examined at higher concentrations than were used in part I of this series.Each amino acid contributes signi... |
The requirements for the transfer of (14)C-phenylalanine from yeast soluble ribonucleic acid to protein in vitro by rice (Oryza sativa L. var. Bluebonnet) ribosomes have been investigated. An absolute requirement for polyuridylic acid, 2-mercaptoethanol, guanosine triphosphate, magnesium, and potassium or ammonium ions... |
By growth experiments in indoleacetic acid-1-(14)C (IAA), and determination of the (14)CO(2) evolved, it has been shown directly that polyphenols synergize IAA-induced growth by counteracting IAA decarboxylation. Sinapic and ferulic acids act like polyphenols. Endogenous polyphenols doubtless exert the same influence i... |
Ascorbic acid oxidase activity in Myrothecium verrucaria extracts resulted in O(2) uptake exceeding 0.5 mole per mole of ascorbic acid and in CO(2) evolution. Measurement of oxidized ascorbic acid at completion of the reaction demonstrated that an average of 10% of the oxidized product disappeared. A comparison of the ... |
An investigation has been made of the possibility of utilizing the potential energy of the contracted state of corn mitochondria to drive Ca + inorganic phosphate accumulation. Contraction was obtained with succinate or NADH oxidation. In the succinate experiments the mitochondria were contracted in buffered KCl layere... |
There is considerable variation among species in their rate of photorespiration, and photorespiration increases greatly at higher temperatures. The addition of an inhibitor of glycolate oxidase, alpha-hydroxy-2-pyridinemethanesulfonic acid, to tobacco leaf disks at 35 degrees stimulated photosynthetic (14)CO(2) uptake ... |
The copper protein plastocyanin has been found to be an essential component of the photosynthetic electron transport chain of Chlamydomonas reinhardi, and in this paper we describe a method for its isolation and purification from the wild-type strain. In addition, we describe some of its properties and compare them wit... |
The accumulation of reducing sugars in potato tubers exposed to low temperatures occurs with concomitant formation of the enzyme invertase. During the initial period of cold treatment when reducing sugars increase rapidly, invertase formation proceeds until the level of enzyme exceeds that of an endogenous macromolecul... |
Electrophoretic and immunological properties of the soluble root protein complement of 6 Medicago sativa L. genotypes in the cold hardened and non-hardened physiological condition were compared. These 6 genotypes were chosen to represent a range of abilities to survive exposure to subfreezing temperatures when in the c... |
Dense cultures of Chlorella grown under our conditions contain large amounts of chlorophyll on a packed cell basis. Upon dilution the cells are, in effect, put into an environment in which light is not limiting and chlorophyll seemingly in excess (at least temporarily). Thus it is not economical for the cell to produce... |
Leaves of dark-grown corn (Zea mays) were illuminated for periods ranging from 3 minutes to 12 hours. The changes in the activities of ribose-5-phosphate isomerase, ribulose-5-phosphate kinase, and ribulose-1,5-diphosphate carboxylase were followed.The activity of ribose-5-phosphate isomerase did not change significant... |
An acetaldehyde dehydrogenase from germinating peanut cotyledons has been purified and its properties have been studied. At the highest purification achieved the preparation is free of alcohol dehydrogenase activity.The enzyme is specific toward diphosphopyridine nucleotide, and can oxidize a variety of aldehydes. The ... |
There are at least 2 amino pools for leucine and for valine in the soybean hypocotyl, a small protein precursor pool and a large inactive pool. The precursor pool decreased in size during incubation of excised hypocotyls presumably because the cotyledonary sources of amino acids had been removed. The precursor pool was... |
Particulate cell wall polysaccharide synthetase from oat coleoptiles could use either guanosine diphosphate glucose or uridine diphosphate glucose; the latter was a much more effective glucose donor. The neutral polymer derived from uridine diphosphate glucose utilization yielded, after cellulase digestion, mostly cell... |
Excised roots of barley (Hordeum vulgare, var. Campana) were incubated in KCl, K(2)SO(4), CaCl(2), and NaCl solutions at concentrations of 10(-5) to 10(-2)n. Changes in substrate solution pH, cell sap pH, and organic acid content of the roots were related to differences in cation and anion absorption. The pH of express... |
Gibberellic acid enhances the synthesis of alpha-amylase in isolated aleurone layers of barley-seeds (Hordeum vulgare var. Himalaya). In the presence of 20 mm calcium chloride the amount of enzyme obtained from isolated aleurone layers is quantitatively comparable to that of the half-seeds used in earlier studies. Afte... |
The effect of sodium chloride added to root medium of pea seedlings on respiratory activity of tissue segments and on isolated mitochondria was studied. Salinization enhances the respiration of leaves about one-third on a fresh weight, dry weight or protein basis. Roots and stems show only 10 to 15% respiratory stimula... |
Lipoxidase, in the cotyledons of squash (Cucurbita moscata) seedlings grown in the dark, reached its peak activity on the fifth day and then declined to its lowest activity on the eighth day. Under continuous irradiation, the rate of enzyme disappearance was accelerated by red (655 mmu) and was retarded by far-red (735... |
Extracts of pea seedlings (Pisum sativum, variety Alaska) oxidize indole-3-acetic acid to a bacteriostatic compound which has been identified as 3-hydroxymethyloxindole. At physiological pH this compound is readily dehydrated to 3-methyleneoxindole, another bacteriostatic agent. The extracts of pea seedlings also conta... |
Protein and soluble nitrogen distribution in different parts of lettuce seedling was studied in light and darkness and in presence and absence of gibberellic acid. In dark, applied gibberellic acid failed to show any marked effect on the nitrogen changes in lettuce. Light inhibits translocation of nitrogen reserves fro... |
Lignin biosynthesis in excised tissues of Sorghum vulgare variety Wheatland milo incubated in air with and without prior infiltration with H(2)O was presumably limited by H(2)O(2) production and was dependent upon an endogenous substrate, probably starch. In solution culture without shaking, this conversion of endogeno... |
Hydroxy-l-proline-induced inhibition of elongation of Avena coleoptile segments was measured in water and in indole-3-acetic acid. This inhibition was completely reversed by l-proline.Time-sequence experiments revealed that some time had to elapse, or some elongation had to occur, prior to the onset of hydroxyproline i... |
Amylase activity has been studied in disks of hypocotyl of Phaseolus vulgaris L. Although some activity is present in untreated hypocotyls, it is greatly increased when disks are incubated 4 days in water containing kinetin (5 mg/liter). Gibberellic acid and 2,4-dichlorophenoxyacetic acid do not increase this activity ... |
Spherosomes of cotyledons of germinating peanuts (Arachis hypogea L.) were examined by electron microscopy and found to be particles about 1.0 to 2.0 mu in diameter bounded by a limiting membrane. Isolated spherosomes appear similar to spherosomes in situ. The isolated spherosomes are composed of 98.1% total lipids, 0.... |
Kinetin-induced expansion of lettuce (Lactuca sativa) cotyledons and inhibition of root are accompanied by parallel changes in protein nitrogen. However, during its inhibition of the longitudinal growth and water uptake of hypocotyl and pea (Pisum sativum) epicotyl sections kinetin markedly stimulates protein synthesis... |
Ozone was found to inhibit oxidative phosphorylation and oxygen uptake in mitochondria of tobacco leaves (Nicotiana tabacum, L. var. White Gold). The inhibition appeared to occur at both substrate and electron-transport chain levels. The inhibition increased with the length of exposure to ozone, however, the phosphoryl... |
A study has been made of the structural requirements for organic acids that increase the yield of ATP formed by spinach chloroplasts in the dark due to an acid-base transition. Dicarboxylic acids of 4 and 5 carbon atoms with 1 pKa in the range of 4.2 to 4.4 and the second at 5.3 to 5.5 are most effective. A fairly good... |
Three enzymes assumed to mediate CO(2) metabolism in corn root tips, P-enolpyruvate carboxylase, malic dehydrogenase, and the malic enzyme, were extracted to determine their relative specific activities and their partitioning between soluble and particulate fractions. The data indicated that the intracellular location ... |
The possible involvement of nucleic acid and protein synthesis in light-regulated chlorophyll formation by rapidly greening leaves has been studied.Removing leaves from illumination during the phase of rapid greening results in a reduction in the rate of pigment synthesis; cessation occurs within 2 to 4 hours. Etiolate... |
The effects of various inhibitors of nucleic acid and protein synthesis on protochlorophyllide synthesis in dark-grown Phaseolus vulgaris var. Red Kidney have been studied. Actinomycin D, chloramphenicol, and puromycin inhibit the regeneration of protochlorophyllide holochrome (detected as a 650 mmu absorption peak) in... |
A crude proteolytic enzyme preparation which hydrolyzes casein was isolated from the cotyledons of squash seedlings. The presence of ethylene diamine tetraacetate or cysteine did not appreciably affect the activity of the preparation. During the course of germination, the level of proteolytic activity increased in the ... |
Some microscope observations of the protein bodies of the cotyledon cells of the soybean (Glycine max) are described, together with changes in their appearance which occur on germination. Density gradient centrifugation permits the isolation of protein bodies from soymeal. They contain about 70% of the protein of the b... |
Less than 10% of the acid p-nitrophenylphosphatase activity of plant extracts was sedimentable under a variety of conditions including zonal centrifugation. The sedimentable fraction did not show the latency properties characteristic of animal lysosomes. We conclude that, at least operationally, plant acid phosphatase ... |
The uptake of alpha-tocopherol and vitamin K(1) by pea stem sections is described. Vitamin K(1) appears to be stable within the plant tissue and is found distributed in all particulate cell fractions following uptake. Only a small proportion of the tocopherol taken up is recoverable and the majority of the compound app... |
Gibberellic acid (GA) enhances the synthesis of alpha-amylase and ribonuclease in isolated aleurone layers and this process is inhibited by abscisin. Removal of gibberellic acid in mid-course of alpha-amylase production results in a slowing down of alpha-amylase synthesis, suggesting a continued requirement of GA for e... |
Soluble proteins extracted from alfalfa roots of hardy and nonhardy varieties were studied in relation to cold hardiness with polyacrylamide gel electrophoresis and quantitative enzyme analysis. Soluble protein content of alfalfa roots increased during hardening in all varieties. Two new isoenzymes with peroxidase acti... |
Anabaena cylindrica grown with nitrate required higher levels of sodium (0.4 meq/l NaCl) to prevent chlorosis than when grown without combined nitrogen (0.004 meq/l NaCl). Nitrite accumulated in sodium-deficient cultures containing nitrate. Amounts of nitrite similar to those found in deficient cultures when added to n... |
The isotope competition method with glucose-U-(14)C as a carbon source has been used to determine whether or not selected compounds contribute carbon to the biosynthesis of protein amino acids in cells derived from Paul's Scarlet Rose. Of 48 compounds tested, 15 contributed carbon to protein amino acids. The results sh... |
Nutritional and light requirements for growth and synthesis of RNA, DNA, and protein by cotyledons excised from 5-day-old seedlings of Raphanus sativus L. were investigated, and the course of synthesis was followed through the cell cycle. The minimum requirements for a net increase in nucleic acid and protein were suga... |
Enzymes involved in malic acid production via a pathway with 2 carboxylation reactions and in malic acid conversion via total oxidation have been demonstrated in mitochondria of Bryophyllum tubiflorum Harv. Activation of the mitochondria by Tween 40 was necessary to reveal part of the enzyme activities. The temperature... |
The initiation of perithecia in the homothallic ascomycete Sordaria fimicola was completely suppressed, without seriously inhibiting vegetative growth, by growing the fungus on an agar medium containing one of the following additions: 1) 1 mum 5-fluorouracil, 2) 10 to 100 mum 6-azauracil, 8-azaguanine or 8-azaadenine, ... |
Experiments have been performed to investigate whether indoleacetic acid changes the balance between the rates of synthesis of different kinds of proteins. Sub-apical sections of etiolated peas were incubated with (14)C- or (3)H-labeled amino acid, and combined to give dual-labeled tissue. Cell fractions were prepared ... |
Sodium stimulated ATPase activity in the nuclei of the meristematic cells, while potassium stimulated it in the mycorrhizae between root cap cells. The detection of these 2 mutually exclusive cation-stimulated ATPases, which both require magnesium-ATP in equivalents, which have a similar optimum pH of about 5.5, and wh... |
Measurements were made over a 4-day period of the effect of added indoleacetic acid (IAA), puromycin, actinomycin D and 5-fluorodeoxyuridine (FUdR) on growth and the levels of total DNA, RNA, protein and cellulase in segments of tissue at the apex of decapitated etiolated epicotyls of Pisum sativum, L. var. Alaska.The ... |
A cell-free system which synthesizes protein was isolated from ;aged' discs of Jerusalem artichoke tubers. The synthetic activity was largely associated with the fraction containing mitochondria. Preparations from freshly cut tissue were virtually inactive but increasingly active preparations were obtained from discs ;... |
Free hydroxyproline inhibits the formation of protein-bound hydroxyproline from proline to a considerably greater extent than it does the incorporation of proline into protein of auxin-treated Avena coleoptiles. This inhibition is greater in the wall than in the cytoplasmic fraction. In the absence of auxin, free hydro... |
The incorporation of uniformly labeled leucine-(14)C into protein by a chloroplast containing fraction from developing primary leaves of bean is reported. Chloroplasts, obtained from week old plants grown in darkness, and then illuminated with white light for 12 hours, were shown to be the principal sites of incorporat... |
The adsorption of chloro-aromatic acids to monomolecular layers of oat squashes is reported in earlier papers but it was not possible by the technique used, to measure unambiguously the adsorption of unsubstituted and 2,6-dichloro-aromatic acids. This has now been achieved by a modification of the earlier method and in... |
A particulate enzyme system from Phaseolus aureus seedlings catalyzes the synthesis of alkali insoluble polysaccharide material from UDP-d-glucose. 80 to 90% of the d-glucose units are joined by beta-1,4 linkages, the remainder being combined by beta-1,3 linkages. It is not known whether the material is a single polysa... |
WHEN ACTINOMYCIN D, PUROMYCIN, STREPTOMYCIN, CHLORAMPHENICOL, AND CYCLOHEXIMIDE, KNOWN INHIBITORS OF PROTEIN SYNTHESIS, WERE APPLIED TO LEAVES OF INTACT SEEDLINGS OR DETACHED LEAVES OF BARLEY PRIOR TO THEIR GREENING, THE SAME GENERAL RESPONSE RESULTED: the light-induced increase in activity of ribulose 1,5-diphosphate ... |
Microsomal fractions isolated from sterile, aged disks of red beetroot incorporate leucine into protein when supplemented with the supernatant fraction, ATP, GTP, and KCl; the incorporation is sensitive to RNase and is not due to bacteria. The microsomal activity is inhibited by puromycin and cycloheximide but is virtu... |
A comparative study was made of the effects of auxin (alpha-naphthalene acetic acid), kinetin (6-furfurylaminopurine) and a mixture of auxin and kinetin applied in vivo on synthesis of RNA and protein and the distribution of such synthesis amongst the subcellular fractions of sections of endocarp from Kentucky Wonder p... |
The uptake of orthophosphate ((32)P) by excised corn roots, Zea mays L. was studied using roots grown on 0.2 mm CaSO(4). Nine concentrations of KH(2)PO(4) from 1 to 256 mum were used at temperatures of 20 degrees , 30 degrees , and 40 degrees . Enzyme kinetic analysis was applied to the data obtained. Two apparent mech... |
The method of evaluating cold injury in woody plants by the use of triphenyl tetrazolium chloride has been refined to eliminate bias associated with visual differentiation between varying degrees of tetrazolium reduction and to predict tissue survival at a later date. An advantage of the method described here is that a... |
Reactions of photosynthetic electron transport and photophosphorylation were studied in preparations from the blue-green alga, Phormidium luridum. Osmotic lysis of protoplasts proved to be a superior technique for the production of cell-free preparations with high enzymatic activity. Such lysed protoplasts sustain high... |
Conidia of Verticillium albo-atrum Reinke and Berthold, collected from shake cultures grown in Czapek broth, were sonified for 4 or 8 minutes or ground frozen in a mortar to obtain cell-free homogenates. These were assayed for certain enzymes associated with respiratory pathways. Malic dehydrogenase was the most active... |
In excised embryos of Fraxinus ornus, the first macroscopic sign of germination is a curvature near the root apex. Histological studies show that this curvature is due to cell elongation on the convex side and is accompanied by cell division. Metabolic changes, manifested by the disintegration of protein bodies and tis... |
The effect of sucrose, Mg(2+) and deoxycholate on the yield of ribosomes from barley leaves was determined and the changes in the amount and the composition of ribosomes during senescence of intact and excised first seedling leaves were examined.The extraction medium containing 20 mm tris-HCl, 0.25 m sucrose, 1 mm MgCl... |
Mevalonate-(14)C was incorporated into (-)-kaurene-(14)C in cell-free extracts of immature pea (Pisum sativum L.) seeds. The identification of (14)C-product as (-)-kaurene was based on: A) comparison with authentic (-)-kaurene on thin-layer and gas-liquid chromatography; and B) oxidation of (14)C-product and (-)-kauren... |
The effects of representative respiratory inhibitors were investigated on the coupled respiration of mung bean mitochondria using succinate and l-malate as substrates. The inhibitors studied were: (I) malonate, (II) amytal and rotenone, (III) antimycin A and 2-n-nonyl-4-hydroxyquinoline N-oxide (NOQNO), and (IV) cyanid... |
During germination of the castor bean all of the contents of the endosperm are ultimately transported to the embryo through the cotyledon or respired. A net loss of nitrogen from the endosperm begins about the fourth day, i.e. at the time when embryo growth and fat breakdown are also beginning. Amino acid analysis of t... |
When applications of certain purines and pyrimidines enhanced the development or maintenance of cold hardiness, the content of water-soluble, trichloroacetic acid-precipitable protein and nucleic acids and tissue pH were higher in treated plants than in controls. The reverse was generally true when the treated plants w... |
Primary and secondary metabolites of inorganic nitrogen metabolism were evaluated as inhibitors of nitrate reductase (EC 1.6.6.1) induction in green leaf tissue of corn seedlings. Nitrite, nitropropionic acid, ammonium ions, and amino acids were not effective as inhibitors of nitrate reductase activity or synthesis. In... |
The senescence of excised discs of primary leaves of Phaseolus vulgaris, L., var. Red Kidney was followed by measuring the net breakdown of protein and chlorophyll. The chemical growth regulators indoleacetic acid, 2,4-dichlorophenoxy-acetic acid, gibberellic acid, kinetin, and 6-benzylaminopurine were relatively ineff... |
Serine transhydroxymethylase (EC 2.1.2.1) has been purified 46-fold from cauliflower (Brassica oleracea var. botrytis L.). The enzyme was completely dependent on the presence of tetrahydrofolic acid for the conversion of serine to glycine. The addition of pyridoxal phosphate gave a large increase in the reaction rate. ... |
A 2-step, 1-dimensional thin-layer chromatographic procedure for isolating indoleacetic acid (IAA) was developed and utilized in investigations of the biosynthesis of IAA from tryptophan-(14)C in cell-free extracts of pea (Pisum sativum L.) shoot tips. Identification of a (14)C-product as IAA was by (a) co-chromatograp... |
Isolated Phaseolus mitochondria will swell spontaneously in buffered KCl and contract with an oxidizable substrate or ATP + Mg(2+). The conditions under which the mitochondria are swollen affect subsequent contraction, substrate oxidation and ion accumulation, but not their oxidative phosphorylation ability. Bovine ser... |
Helminthosporium victoriae toxin, which affects only hosts of the toxin-producing fungus, causes loss of electrolytes from roots, leaves, and coleoptiles of treated plants. Root hair cells lost the ability to plasmolyze after 20 minutes exposure to toxin in solution; comparable resistant cells retained plasmolytic abil... |
Gibberellic acid (GA(3)) induces invertase activity within 6 hours in Avena stem segments that are incubated in the dark at 23 degrees . The maximum amount of promotion is about 5 times that of invertase activity in untreated segments. GA(3) causes significant promotion of invertase activity at concentrations as low as... |
Selective inhibitors were used to study the connection between nucleic acid synthesis and indoleacetic acid (IAA) induction of cell enlargement. Actinomycin D (act D) and azaguanine (azaG) almost completely inhibit IAA-induced growth in aged artichoke tuber disks when they are added simultaneously with IAA. In contrast... |
It has been shown previously that an increase in ribulose diphosphate carboxylase activity occurs upon brief illumination of leaves of dark-grown Zea mays plants; an increase in ribose 5-phosphate isomerase occurs after prolonged illumination. Both of these responses to illumination are inhibited by chloramphenicol.The... |
Malic enzyme was found in both bean rust and cat stem rust uredospores. In bean rust uredospores it was shown to catalyze the formation of pyruvic acid from l-malic acid and to synthesize malic acid from pyruvic acid and CO(2). The malic enzyme from bean rust uredospores was specific for NADP and dependent on manganous... |
Roots and shoots of corn seedlings (Zea mays L. var. Dixie 18) germinated in trifluralin (alpha,alpha,alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) solutions are characterized by radial enlargement of the cortical cells and by multinucleate cells in the meristematic regions. Trifluralin inhibits elongation of A... |
Abscission zone tissue of citrus was shown to have a higher rate of protein synthesis than tissue distal or proximal to it, based on the incorporation of leucine-1-(14)C. The proximal tissue had the slowest rate of protein synthesis. As the tissue approached abscission, the rate of synthesis in the abscission zone decr... |
The light induced synthesis of phenylalanine ammonia-lyase in disks cut from potato tubers is very sensitive to cycloheximide. Synthesis is inhibited 50% in disks cultured on 5 mum cycloheximide instead of water and almost completely in disks aged in the presence of 10 mum inhibitor. Inhibition is irreversible. Fresh d... |
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