bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of Tobacco Leaf Glycolate Oxidase Activity by Chlorogenic Acid and Other Polyphenols
Authors: DE JONG DONALD W. 
Published: April 2006

AbstractGlycolate oxidase extracted from tobacco leaves (Nicotiana tabacum L. cv. NC‐95) and assayed by the 2,6‐dichlorophe‐nolindophenol reduction method was stimulated by chlorogenic acid and other o‐diphenols but not by p‐diphenols such as hydroquinone. Chlorogenic acid also protected the enzyme against certain enzyme antagonists. A novel assay utilizing horseradish peroxidase with the chromogen o‐dianisidine was developed for detecting glycolate oxidase in conjunction with disc electrophoresis. Dissociation of glycolate oxidase into an active monomer during ammonium sulfate fractiona‐tion was confirmed electrophoretically. After electrophoresis, flavin mononucleotide was required for monomer activity whereas chlorogenic acid was inhibitory to enzyme band development.
Simulation of Rhythmic Tree Growth under Constant Conditions
Authors: BORCHERT R. 
Published: April 2006

AbstractThe observed rhythmic growth of trees under relatively uniform environmental conditions has been ascribed by some authors to endogenous factors, by others to slight fluctuations of environmental factors. A model for the simulation of rhythmic growth was developed based on the assumption that endogenous rhythms can result from feedback interaction between two potentially continuous processes, like shoot and root growth, if the slower process is rate limiting for the faster one. Rhythmic growth in trees would be the consequence of feedback mechanisms needed for maintaining a constant shoot: root ratio. Period length of the rhythms depends upon the rates of the growth processes involved. Environmental factors modify period length through affecting growth rates. Growth patterns predicted by the model compare well with growth measurements of tropical trees. The transition from intermittent to continuous growth, as observed under certain conditions, can be simulated by varying a single parameter in the model.
Subcellular Distribution of Basal and Cation‐sensitive ATPases in Roots of Phaseolus vulgaris
Authors: WILKINS J. A. , THOMPSON J. E. 
Published: April 2006

AbstractA smooth microsomal fraction isolated from homogenates of Pbaseolus vulgaris root tissue has been found to possesss a highly active basal ATPase (measured in the absence of added cations). The microsomal membranes also feature a cation‐sensitive ATPase which responds to Mg2+, Na+ and K+, but in a manner that is highly variable with pH. In contrast, membrane fragments prepared by a technique designed to yield purified plasma membrane were capable of little or no hydrolysis of ATP either in the presence or absence of added cations. This suggests that the microsomal activity is a reflection of membrane‐bound ATPase which has been derived from cytoplasmic membranes, possibly the tonoplast, rather than plasma membrane.
Abscisic Acid Inhibition of Gibberellic Acid and Cyclic 3′,5′‐Adenosine Monophosphate Induced α‐Amylase Synthesis
Authors: BARTON K. A. , VERBEEK R. , ELLIS R. , KHAN A. A. 
Published: April 2006

AbstractThe induction of α‐amylase synthesis in barley aleurone by cyclic 3′,5′‐adenosine monophosphate or GA3 was inhibited by abscisic acid. The concentration of ABA required to inhibit α‐amylase induction by the cyclic nucleotide in the extract was one‐fiftieth to one hundredth of that required for GA3‐induced α‐amylase. It is concluded that the effects of ABA on GA3 and cyclic nucleotide induced α‐amylase synthesis in the aleurone are independent and indirect.
Effect of Light, Temperature and Substrate during Spore Formation on the Germinability of Conidia of Colletotrichum falcatum
Authors: SINGH PRITAM 
Published: April 2006

AbstractThis paper presents results on the effect of light, temperature and substrate during spore formation on the germinability of conidia in Colletotrichum falcatum. Light seems to have no effect on the germination of conidia unless the cultures were exposed to a high intensity of light during sporulation, in which case the spores showed a reduced germination and an increased appressoria formation. Conidia produced at temperatures higher than the optimum showed better germination and less appressoria formation than the spores produced at the temperature optimum for the growth and sporulation of the fungus. A similar increase in germination was also observed in conidia obtained from inoculated sugarcane leaves as compared to those produced on culture media.The light type virulent isolates of C. falcatum showed greater sensitivity to all these treatments than the dark type weakly pathogenic isolates.
La dormance embryonnaire chez Taxus baccata: Influence de la composition du milieu liquide sur I'induction de la germination Par
Authors: LE PAGE‐DEGIVRY M. TH. , GARELLO G. 
Published: April 2006

AbstractEmbryo dormancy of Taxus baccata var. fastigiata is eliminated when cultured continuously in nutritive liquid medium. An equivalent percentage of germination is obtained when the embryos are transferred to agar medium after 8 days of liquid culture. There is no morphological development of the embryo during the period in the liquid medium. But we have ascertained that water‐soluble germination inhibitors present in the embryo are leached out into the medium, permitting germination.Germination is totally absent when the embryos are cultured continuously in distilled water, alone or with minerals; incidental in sucrose solution; and maximal when the medium contains sucrose and Ca2+ or K+ ions.The extent of germination on agar medium depends upon the composition of the liquid medium in which the embryos are cultured for the initial 8 days. But this preliminary culture in the liquid medium does not always remove the endogenous inhibitors, irrespective of its composition. This can be achieved only in the presence of sucrose; and this process can be made more effective by the addition of Ca2+ ions.
Utilization of Carbohydrates by Rhynchosporium secalis II. Absorption and Metabolism of Glucose, Galactose and Galacturonic acid
Authors: AYRES P. G. , OLUTIOLA P. O. 
Published: April 2006

AbstractGlucose, galactose and galacturonic acid were taken up at different rates by the fungus Rhynchosporium secalis and were intracellularly converted to other forms of carbohydrate at different rates. These differences explain why, when there is only a single source of nutrient carbon in the growth medium, development of the fungus is greatest when glucose is present and least when galactose is present.Glucose and galactose were taken up by the same mechanism for their uptake showed a reciprocal competitive inhibition. Uptake mechanisms had a high affinity for glucose (apparent Km 2.76 mM) and galacturonic acid (apparent Km 3.10 mM) and a low affinity for galactose (apparent Km 29.67 mM). After uptake, galactose accumulated in the mycelium, whereas glucose and galacturonic acid were rapidly converted to other soluble carbohydrates, principally trehalose and mannitol. The insoluble carbohydrates within the mycelium were little affected by the type of carbohydrate that was supplied to the fungus.
Peptide‐Induced Morphogenesis in the Nematode‐Trapping Fungus Arthrobotrys oligospora
Authors: NORDBRING‐HERTZ BIRGIT 
Published: April 2006

AbstractThe present investigation shows the ability of peptides to induce capture organ formation in Arthrobotrys oligospora when applied in a synthetic low nutrient medium.Under certain conditions casitone was shown to induce capture organ formation. The active principle in casitone was concentrated and purified by alternating procedures of ion exchange chromatography and gel chromatography in pyridine‐acetic acid buffers. Crude casitone solutions were applied to columns of Dowex 50 W‐X2 and eluted stepwise with 0.1–1.0 M pyridine‐acetic acid pH 3.2–5.1. Active portions, free from most acid and neutral amino acids, were further purified on columns of Sephadex G‐10 in 0.1 M pyridine‐acetic acid pH 4.6. Aromatic amino acids and large molecules in the void volume could be separated from an active peptide mixture which was subjected to renewed ion exchange chromatography on Bio‐Rad AG 50 W‐X2. By stepwise and/or gradient elution in 0.1–0.5 M pyridine‐acetic acid pH 3.2 fairly purified peptides were obtained.The composition of the test medium is an important factor in spontaneous capture organ formation. The peptides isolated from casitone induced capture organ formation, when given to the fungus in a synthetic mineral salt medium supplied with thiamin and biotin. Similar effects were obtained with small synthetic peptides in the same concentration (0.1 mg/ml). A large variety of peptides seem to be active when applied in a suitable medium. This was especially true for peptides with Rf > Rfleu on thin layers of cellulose developed with butanol‐acetic acid‐water (4: 1: 1). Of the peptides investigated valyl‐peptides exerted the most drastic effect.
Antibiotic Activity of the Chrysophyte Ochromonas malhamensis
Authors: HANSEN JENS AAGE 
Published: April 2006

AbstractThe effects were studied of extracts from the chrysophyte Ochromonas malhamensis on Staphylococcus aureus, Bacillus megaterium, Bacillus subtilis and Escherichia coli. The extracts contained three different antibiotically active substances, one of which was produced during the extraction. The other two had no effect on E. coli, but inhibited the growth of the three other bacteria.The present experiments show that one of the products increases its antibiotic activity when exposed to visible light, and that its activity is enhanced by boiling the extracts for 5 minutes. The other active substance is not affected by light, but shows increased activity after being boilt for 5 minutes.
Mineral Nutrient Requirements ofVaccinium vitis idaeaandV. myrtillus
Authors: INGESTAD TORSTEN 
Published: April 2006

AbstractThe mineral nutrient requirements ofVaccinium vitis idaeaL. andV. myrtillusL. have been studied. It is found that the optimum nutrient proportions are similar to those of birch seedlings except for a relatively low potassium requirement. The nitrogen sources ammonium and nitrate are both usable at low concentrations. A system with both sources present seems preferable. The ammonium uptake is then much more rapid than the nitrate uptake. The optimum total concentration falls within the low salt range and is about the same as found for birch seedlings, but the sensitivity to high salt concentrations is more pronounced in the Vaccinium species. A very marked characteristic of the nutrient absorption is the rapid calcium uptake. The results are discussed in relation to similar experiments with birch and cucumber seedlings, representing species with a wide or calcareous ecological adaptation.
Properties of the Ribosome‐Bound Peroxidase/IAA‐oxidase of Cabbage Roots
Authors: RAA JAN 
Published: April 2006

AbstractThe ribosomal fraction of cabbage roots contains IAA‐oxidase and peroxidase activity. EDTA dissociates these enzymes from the ribosomal RNA. The IAA‐oxidase of intact ribosomes shows allosteric, whereas that of EDTA disintegrated shows conventional kinetics. Gel electrophoresis separated three peroxidases from the ribosomal RNA.
The Mechanism of Low Temperature Dormancy in Mature Seeds of Syringa Species
Authors: JUNTTILA OLAVI 
Published: April 2006

AbstractThe mechanism of seed dormancy at low temperatures (15‐9°C) was investigated in the seeds of Syringa josikaea, S. reflexa and S. vulgaris. Low temperature dormancy in Syringa species was mainly imposed by endosperm embedding the radicle. Different degrees of embryo dormancy may occur in S. reflexa seeds. In most cases the low temperature dormancy was broken completely by removing the endosperm around the radicle. The endosperm did not seem to contain significant quantities of germination inhibitors, and the results indicate that it prevents germination mainly due to its mechanical resistance. The mechanical resistance of endosperm did not change during chilling or during induction of dormancy by high temperature incubation. The strength of the endosperm decreased rapidly in non‐dormant seeds before visible germination. Similar changes were not observed in dormant seeds. Generally, the strength of the endosperm was lower in the non‐ (or less) dormant species S. josikaea and S. vulgaris than in the more dormant S. reflexa seeds. The growth potential of the embryos, measured as their ability to germinate in osmotic solutions (mannitol or polyethylen glycol 4000), was increased by chilling and by GA3‐treatment. The growth potential of untreated S. josikaea and S. vulgaris embryos was generally higher than that of S. reflexa embryos. Acid ethyl acetate fractions of methanol extracts from embryos of all three species contained substances with GA3‐like activity in the lettuce hypocotyl test. The activity was found at Rf 0.9–1.0 on paper chromatograms run in distilled water. No significant changes in the activity were detected during chilling or prior to visible germination.
Gibberellin‐like Substances in Developing Barley Grain and Their Relation to Dry Weight Increase
Authors: MOUNLA M. A. Kh. , MICHAEL G. 
Published: April 2006

AbstractGibberellin‐like activity of two varieties of barley (Hordeum vulgare L.) at different stages of grain development was determined by barley endosperm bioassay (acid phosphatase bioassay).Activity of the acidic ethyl‐acetate fraction (“free” GAs) in both varieties displayed two maxima, a first maximum at the 9th day and a second one 20 to 21 days after pollination.Activity of the n‐butanol fraction (“bound” GAs) first dropped to a minimum level at the 9th day, then increased to reach a maximum 32 days after pollination, and finally decreased again towards maturity. From the 9th day after pollination, a conversion of “free” GAs to “bound” GAs has probably occurred.From the 12th day after pollination, the curves of rate of dry weight increase and of “free” GAs run nearly parallel, but the latter reached its maximum about 2–4 days earlier than the former.The results indicate that gibberellins may participate in the regulation of the accumulation processes into the barley grain.
Spring Mobilization of Protein Nitrogen in Apple Bark
Authors: TROMP J. , OVAA J. C. 
Published: April 2006

AbstractMobilization of protein nitrogen in the spring was studied in bark of stems of unringed and double stem‐ringed apple rootstocks M.7 given different nitrogen treatments.A ready protein hydrolysis occurred; the proteins contributed the greater part of the storage nitrogen exported to the growing parts. Protein hydrolysis was little affected by the supply of newly absorbed nitrogen. Movement of nitrogen out of the bark between the rings could not be demonstrated. Protein breakdown in the isolated bark sections was slightly reduced.Arginine was the predominant amino acid in the proteins of the trees with a high level of storage nitrogen but was not conspicuous in the low‐nitrogen trees. The protein composition changed little during hydrolysis. Only the share of arginine in the high‐nitrogen trees dropped appreciably. It is suggested that the high‐nitrogen trees possess a special storage protein characterized by a high arginine content.Analysis of the nitrogen fraction of isolated bark sections showed that the composition of the soluble nitrogen was characterized by a high level of asparagine and especially of arginine, and was quite different from the composition of the proteins. The data suggest that the asparagine in particular originated largely from transformation of the various amino acids set free during protein hydrolysis.
Evaluation of UV‐Induced Mutants of Chlorella vulgaris for Single Cell Protein I. The Screening Effect of Cycloheximide and 6‐Methylpurine
Authors: PASSERA CALVINO , FERRARI GIOVANNI 
Published: April 2006

Abstract Chlorella vulgaris was irradiated with UV doses allowing a 0.1 per cent survival. Dark recovery and photoreactivation were carried out either in the presence or in the absence of an inhibitor of protein synthesis. Faster growing and faster greening colonies were selected, and the amino acid composition of the mutant strains were evaluated. Higher growth and photosynthetic rates, higher chlorophyll content and lower respiration rate were shown by all mutants irrespective of the selection procedure. Selection against cycloheximide led to higher protein and RNA, but lower carotenoid content, whereas mutants selected against 6‐methylpurine showed, in addition to a protein and carotenoid increase, a more favourable protein: RNA ratio.
Chlorophyll Formation in the Dark I. Chlorophyll in Pine Seedlings
Authors: BOGDANOVIĆ M. 
Published: April 2006

AbstractIn black pine (Pinus nigra) chlorophyll was first detected two days after planting of the soaked seeds. There was a slight change in the chlorophyll content between two and five days, then a faster chlorophyll synthesis started. The maximum chlorophyll content was found after 15 days of germination. Thereafter the content showed a gradual decrease. The chlorophyll a/b ratio decreased from 10 at two days to 3 after five days. Protochlorophyllide did not accumulate after 6 days of germination.
Chlorophyll Formation in the Dark II. Chlorophyll in Wheat Leaves Transplanted to Pine Megagametophytes
Authors: BOGDANOVIĆ M. 
Published: April 2006

AbstractChlorophyll production in wheat (Triticum vulgare) leaves takes place in the dark when wheat embryos are transplanted to the megagametophytes of black pine (Pinus nigra).The chlorophyll content in the wheat leaves is about half that in black pine cotyledons of the same age.
Effect of Water Stress, Temperature, and Light on Photosynthesis in Alder Seedlings
Authors: HARI PERTTI , LUUKKANEN OLAVI 
Published: April 2006

AbstractSeedlings of Alnus incana (L.) Moench were studied in controlled environmental conditions. Net photosynthetic capacity of four plants simultaneously as well as light, temperature, and atmospheric water pressure deficit were continuously recorded during approximately two months. The potted plants were continuously given known quantities of water.Two different effects of water stress were found in the experimental plants. When sufficient amounts of water had been available to them, photosynthetic CO2 fixation rates largely followed the variation in temperature and light. On the other hand, after prolonged water stress, higher temperatures caused a large decrease in net CO2 uptake even if the plant apparently had sufficient water during the actual measurements. Possible mechanisms for this effect are discussed.Effects of water stress on photosynthesis were studied at a constant temperature as well as in conditions where temperature, light, soil water content, and atmospheric water vapor pressure were allowed to vary in a complex pattern. Mathematical models for expressing net CO2 uptake as a function of environmental variables were constructed for both of these experimental situations. However, only the latter approach clearly demonstrated the fundamental role of temperature in controlling the photosynthesis of plants under water stress.
Mating Reaction in Saccharomyces cerevisiae. IV. Retardation of Deoxyribonucleic Acid Synthesis
Authors: SHIMODA CHIKASHI , YANAGISHIMA NAOHIKO 
Published: April 2006

AbstractWhen a and a type haploid cells of Saccharomyces cere‐visiae were mixed and cultured, deoxyribonucleic acid synthesis was retarded but ribonucleic acid and protein syntheses were not. It was found that culture filtrate of a type cells inhibited deoxyribonucleic acid synthesis of a type cells and that of a type cells inhibited that of a type cells. Thus, sex‐specific diffusible substances secreted by opposite mating type cells are thought, at least partly, to be responsible for the retardation of deoxyribonucleic acid synthesis.
Glycolate Metabolism in Eurasian Watermilfoil (Myriophyllum spicatum)
Authors: STANLEY RONALD A. , NAYLOR A. W. 
Published: April 2006

AbstractThe metabolism of glycolate by Eurasian watermilfoil (Myriophyllum spicatum L.), a submersed angiosperm, was studied by feeding radioactive glycolate and glyoxylate and by analysis of glycolate and glycolic acid oxidase. Evidence for operation of the glycolate pathway is given. Glycolic acid oxidase occurs at levels comparable to amounts in species showing photorespiration. This species has a high affinity for CO2 and a possible mechanism for it is described.
Golgi Apparatus Mediated Polysaccharide Secretion by Outer Root Cap Cells of Zea mays. III. Control by Exogenous Sugars
Authors: JONES DANIEL D. , MORRE D. JAMES 
Published: April 2006

AbstractSugars supplied to germinating seedlings of maize (Zea mays L.) regulate the secretion of polysaccharides by the outer cells of the root cap. The polysaccharide secreted by these cells adheres to the root tip as a droplet and the size of the droplet was used to quantitate polysaccharide secretion. The polysaccharide contains glucose, galacrose, and galacturonic acid residues with smaller quantities of mannose, arabinose, xylose, fucose and rhamnose. These sugars supplied to maize seedlings had marked effects on the rate of polysaccharide secretion by root tips. The effects on secretion were independent of the growth rates of the roots. Glucose, fucose and xylose increased droplet size 1.5–2 fold (as did sucrose, maltose, lacrose, fructose and ribose) whereas galactose, arabinose and galacturonic acid were inhibitory. Mannose increased dropler size 5–7 fold.The marked effect of mannose on polysaccharide secretion was due to an increased rate of secretion combined with a longer phase of extrusion of polysaccharide into the forming droplet. The effect of mannose was partially reversed by inorganic phosphate and other sugars (except for fucose which had no effect or promoted secretion in the presence of mannose). In contrast to sucrose, mannose stimulated secretion in a maize variety having a high sugar endosperm (high endogenous sugar). The results suggest that regulation of secretion by mannose is due to an alteration of normal sugar metabolism; whereas stimulation of secretion by sucrose and other sugars may be due to an increased availability of sugars for metabolism.
The Influence of Heat Processing and Mechanical Disintegration on Yeast for Single‐Cell Protein
Authors: MOGREN HAKAN , HEDENSKOG GUDMUND , v. HOFSTEN ANGELICA 
Published: April 2006

AbstractYeast was processed by means of different technical drying procedures, heating in water suspension, and mechanical disintegration. The influence on the ultrastructure, the nutritive value and on the availability of the cell nitrogen‐containing compounds to chemical extractants was studied.On micrographs no cell wall disrupture could be observed after any of the heat treatments. The internal cell structure was affected at the higher temperatures. After drum drying this structure was destroyed to a large extent. The heat treatments increased the nutritive value compared to unheated yeast cells but did not increase the availability of the cell content to chemical extractants. Mechanical disintegration increased both the nutritive value and the availability to chemical extractants.Heat processes and mechanical disintegration give high nutritive value to the yeast. Mechanical disintegration is advantageous when processing steps such as extraction with chemicals are necessary for obtaining specific protein products.