bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Role of Branched-Chain Amino Acids in Protein Turnover of Skeletal Muscle. Studies in vivo with L-Norleucine
Authors: Schott Klaus-Joachim , Gehrmann Jochen , Potter Ulla , Neuhoff Volker 
Published: August 2018

Abstract
1. The effect of ʟ-norleucine, an isomer of leucine, on protein metabolism in vivo was studied in suckling rats. Rats were injected subcutaneously with various doses of ʟ-norleucine (0.5 and 5.0 μmol/g body wt.) every 12 h from 3 to 15 days post partum. Protein concentration, amino acid concentrations, and incorporation of [3H]tyrosine into protein were analyzed in liver, muscles of thigh and small intestine. Amino acid concentrations and insulin levels in serum were also measured.
2. At 5 days of age, norleucine induced an increase in protein concentration of skeletal muscle with an increased incorporation of [3H]tyrosine into protein indicating an accelerated protein synthesis. Changes in protein metabolism were paralleled by alterations in the amino acid pattern of this tissue.
3. When protein concentration and protein synthesis were increased in skeletal muscle, protein concentration of small intestine was decreased, accompanied by elevated levels of amino acids in tissue. Protein synthesis of small intestine was not altered by the norleucine treatment. The results suggest a close interrelationship between skeletal muscle and small intestine with respect to protein turnover.
4. The effects of norleucine were less pronounced at 10 and 15 days of age, which indicates a metabolic adaptation to the treatment.
5. Alterations in amino acid concentrations of tissue due to changes in protein metabolism were not uniform but tissue-specific.
6. Current concepts for explaining the effects of branched-chain amino acids (BCAA) on protein turnover in skeletal muscle are based on the assumption that the BCAA or leucine alone might become rate-limiting for protein synthesis in muscle under catabolic conditions. The amino acid analogue norleucine, however, cannot replace any of the BCAA in protein. Additionally, norleucine affected protein metabolism in highly anabolic organisms.
Therefore, the present thoughts on this issue appear to be incomplete.
Regression of the Time-Keeping Ability in Carabid Beetles by Phylogenetic Adaptation to Cave Conditions
Authors: Martin Wolfgang , Weber Friedrich 
Published: August 2018

Abstract
Locomotor activity patterns of six cavernicolous carabid species representing the course of regressive evolution have been investigated under constant conditions. The analysis establishes new relationships between the circadian structure of the activity patterns observed under constant conditions (LL and D D) and the phylogenetic adaptation to cave conditions. This is due to the mathematical method used for investigating the activity patterns, i. e. the Wigner-Ville spectrum that enables the evaluation of nonstationarities. It overcomes the hypothesis of stationarity which was the base of previous examinations. The new method delivers a more refined gradual decrease of the stability of the circadian pattern of activity in cavernicolous beetles than could be achieved by classical periodogram analysis. It is also shown that the locomotion patterns of extremely evolved troglobitic clearly deviate from a purely signal-free (white noise) structure. Possible time­keeping mechanisms that may cause the measured stabilities and regressive lines of possible evolutionary development are discussed.
Comparison of pH Changes and Elicitor Induced Production of Glyceollin Isomers in Soybean Cotyledons
Authors: Osswald Wolfgang F. , Zieboll Sigrid , Elstner E. F. 
Published: August 2018

Abstract
During the incubation of soybean cotyledons with Pmg-elicitor for 22 hours the pH of the diffusion droplets increases from 7.2 to 8.3. This pH-shift is a precondition for the formation of the typical red colour of the diffusion droplet. After inhibiting the pH-shift by the use of 100 mм phosphate or Tris buffer instead of 10 mм buffer as solvent for the elicitor, the red colour is no longer formed with the exeption of 100 mM Ammediol buffer. However, the normal pattern of pterocarpan induction can be measured in the absence of the red colour in the diffusion droplet. Tris and Ammediol buffers exhibited a smaller pterocarpan induction as compared to phosphate buffer as solvent for the Pmg-elicitor.
Isoneorautenol and Other Pterocarpan Phytoalexins from Calopogonium mucunoides
Authors: Ingham John L. , Tahara Satoshi 
Published: August 2018

Abstract
Following inoculation with the fungus Helm inthosporium carbonum , excised leaflets of the tropical papilionate legume Calopogonium mucunoides have been found to produce isoneorautenol, a new dimethylpyrano-substituted isoflavonoid (pterocarpan) phytoalexin. This compound accumulates together with dem ethylm edicarpin, neodunol, tuberosin, sophorap-terocarpan A, and a sixth highly antifungal isoflavonoid (calopocarpin) characterised as 3,9-dihydroxy-2-(3,3-dimethylallyl)pterocarpan. Chromatographic and spectroscopic examination of ‘hom oedudiol’ (a pterocarpan from N eorautanenia edulis roots previously considered to possess the structure now assigned to calopocarpin) has shown that in reality this substance is identical with sophorapterocarpan A. The systematic relationship of Calopogonium to other genera within the legume tribe Phaseoleae is briefly discussed.
The Regulation of Acetyl Coenzyme A Synthesis in Chloroplasts
Authors: Treede Hans-Jürgen , Heise Klaus-Peter 
Published: August 2018

Abstract
The enzymatic activities of the pyruvate dehydrogenase complex (PDC) and acetyl-CoA synthetase (ACS) have been compared in extracts of plastids isolated from spinach leaves and from both green and etiolated pea seedlings. A ll plastid preparations were shown to be capable of synthesizing acetyl-CoA, not only via acetyl-CoA synthetase, but also via the pyruvate dehydroge­ nase complex, though, with different activities. Both pathways are apparently under metabolic control. Thus, the substrate levels in photosynthetically active spinach chloroplasts appear to favor acetyl-CoA synthesis via ACS (apparent Km for acetate of 0.1 mм) , because calculated stromal pyruvate levels (0.1 m M) appear to limit its formation via the PDC (apparent Km for pyruvate of 0.2-0.3 nм) . In spinach chloroplasts, therefore, the PDC pathway seems to be predominantly involved in providing precursors for branched-chain amino acid biosynthesis (vali­ne, leucine and isoleucine). Acetyl-CoA, synthesized via ACS, may additionally function as an inhibitor of the chloroplast PD C , because, as in mitochondria, relatively low concentrations of the end products NADH and acetyl-CoA strongly inhibit the PD C in chloroplast extracts. On the other hand, comparatively high concentrations of MgATP, a cofactor for ACS, inhibited the PDC complex. The pH optimum of about 8 and the high Mg-requirement distinguishes both enzymes from mitochondrial PDC and reflects an accomodation to stromal conditions in photosynthetically active chloroplasts.
Flavonoid Glycosides from Thymus membranaceus
Authors: Tomás Francisco , Hernández Luis , Barberán Francisco A. T. , Ferreres Federico 
Published: August 2018

Abstract
Thymus membranaceus is an endemism of southeastern Spain, which belongs to section Pseudothymbra of genus Thymus. In this work we have achieved an investigation of the flavonoid glycosides present in the aerial parts of this plant. Among the compounds identified are the rare luteolin-7-0-β-D-xyloside, luteolin-7-0-β-D-[rhamnosyl (1→2)glucoside] and luteolin-7-0-β-D-[xylosyl (1→2)glucoside] previously not known to occur in the Labiatae.
Synthesis of 1,2-Dipalmitoyloxypropyl-3-(2-ammoniumethyl) Phosphinate
Authors: Moschidis Michael C. 
Published: August 2018

Abstract
The total synthesis of 1,2-dipalmitoyloxypropyl-3-(2-ammoniumethyl) phosphinate, the phosphino-analog of phosphatidyl ethanolamine is described.
The phosphinate analog of phosphatidyl ethanolamine has been prepared by an Arbusov type of reaction between a diacyl-glycerol bromohydrin and 2-bromo-ethylphosphonic acid dimethyl ester for 48 h at 178 °C, followed by a reaction with aq. ammonia to yield the final product.
The product was characterized by elemental analysis, phosphono-phosphorus determinations and IR spectroscopy.
Physicochemical Characterization of Tetraetherlipids from Thermoplasma acidophilum
Authors: Blöcher Detlef , Gutermann Raymund , Henkel Birgit , Ring Klaus 
Published: August 2018

Abstract
By means of differential thermoanalysis, the miscibility of the main polar tetraether lipid of Thermoplasma acidophilum with two ester lipids, dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylglycerol, resp., in the presence of excess water was studied. It is shown that with increasing fraction of tetraether lipid in the mixture, the transition range of dipalmitoyl phosphatidylcholine is broadened and the temperature of the maximum heat flow (Tm) is shifted to lower temperatures; furthermore, the enthaply change (ΔH) of the transition declines. Similar results were obtained with mixtures of tetraether lipid with dipalmitoyl phosphatidylglycerol. It is therefore concluded that the main polar tetraether lipid of Thermoplasma acidophilum , which essentially forms monomolecular layers, is able to form stable common phases with bilayer-forming ester lipids. Miscibility of the tetraether lipid with dipalmitoyl phosphatidylglycerol, which are both monovalent anions at neutral pH, is also observed in the presence of high proton or calcium ion concentrations.
Occurrence and Characteristics of Amino Alcohols and Cyclohexenone. Components of Fungal Mycosporines
Authors: Lemoyne F. , Bernillon J. , Favre-Bonvin J. , Bouillant M. L. , Arpin N. 
Published: August 2018

Abstract
After determination of hydrolysis conditions which allow the best recovery of the mycosporine components (cyclohexenone 1 and the amino alcohols 2 and 3), these compounds have been searched into mycelia of several fungi. In some of them, 1 was unambiguously detected, although in minute quantities, whilst the unknown natural 2 and 3 could not be identified. So, two alternative pathways of mycosporine biogenesis are under investigation.
Studies on Sporopollenin Biosynthesis: The Effect of Inhibitors of Carotenoid Biosynthesis on Sporopollenin Accumulation
Authors: Prahl A.-K. , Springstubbe H. , Grumbach K. , Wiermann R. 
Published: August 2018

Abstract
1. The unequivocal chemical composition of sporopollenin is unknown. Ir was often hypothesized that sporopollenin represents a derivative of carotenoids and/or carotenoid esters. Proceeding from this working hypothesis the influence of inhibitors of carotenoid biosynthesis (DPA, nicotine, Sandoz) on the sporopollenin accumulation was studied in order to test whether an intact carotenoid metabolism is involved.
2. Drastic changes in carotenoid spectra as well as in carotenoid patterns in pollen extracts were used as a “marker” for the uptake and transport of the inhibitors into the anther loculus, the site of sporopollenin biosynthesis. Of the three inhibitors of carotenoid metabolism, DPA, nicotine and Sandoz, only Sandoz appeared to influence carotenoid metabolism in the anthers.
3. After application of Sandoz the sporopollenin accumulation in anthers and pollen was only slightly affected. The amount of sporopollenin after treatment is similar to, or possibly even marginally higher than the control, if dry weight is chosen as reference. If the amount is expressed with respect to one pollen grain, the content is very slightly decreased in the case of pollen from treated plants.
Therefore, it is concluded that severe interference in carotenoid biosynthesis does not result in a subsequent drastic inhibition of sporopollenin biosynthesis.
4. A significant increase of PAL activity under the influence of Sandoz indicates that effects upon phenylpropanoid metabolism are possible.
Effects of Norfloxacin and Rifampicin on Growth and Streptolysin S Production in Hemolytic Streptococci
Authors: Taketo Akira , Taketo Yoriko 
Published: August 2018

Abstract
Norfloxacin, a nalidixic acid analogue, inhibited streptolysin S (SLS) production when added to young streptococcal culture. DNA synthesis was mainly affected, but increment of cell mass. RNA and protein was also significantly reduced in streptococci treated with norfloxacin. In stationary phase cells and in the washed resting bacteria, the toxin production was resistant to the drug. Pretreatment with norfloxacin did not abolish the cellular capacity to produce SLS. Although extracellular SLS was detectable at log phase of streptococcal growth, enhanced production of the toxin occurred upon cessation of coccal multiplication. In contrast to norfloxacin, lower concentration of rifampicin inhibited SLS production, even added at late log or early stationary phase. Roles of growth phase, medium and carrier in induction of SLS production were analyzed as well.
Mandibular Gland Secretions as Alarm Pheromones in Two Species of the Desert Ant Cataglyphis
Authors: Hefetz Abraham , Lloyd Helen A. 
Published: August 2018

Abstract
Mandibular gland secretion of two Cataglyphis species were chemically analyzed by combined gas chromatography mass spectrometry. The exudates produced by C. bombycina consisted of citronellol and geraniol while that of C. nigra contained only geraniol.
The reaction of both species to the glandular secretions was alarm and recruitment. While the reaction of C. bombycina was strong, that of C. nigra was relatively mild.
A Photoreversible 39 kDalton Fragment from the Pfr Form of 124 kDalton Oat Phytochrome
Authors: Reiff Ulrich , Eilfeld Peter , Rüdiger Wolfhart 
Published: August 2018

Abstract
Limited proteolysis of 124 kdalton oat phytochrome in the Pfr form is described which leads to a photoreversible 39 kdalton fragment. Whereas the absorption maximum of the Pr form is only slightly shifted (from 667 to 660 nm) no long-wavelength band is observed in the Pfr form. A “bleached” (i.e. low absorbing) form appears instead with a broad absorption maximum at 640 nm. This property corresponds with that of a 40.3 kdalton fragment obtained from pea phytochrome by limited proteolysis (Yamamoto and Furuya, Plant and Cell Physiol. 24, 713, 1983). Dark reversion of the bleached form to the Pr form is faster (t1/2 - 101 min) than dark reversion of 118 kdalton or 60 kdalton Pfr. Low temperature spectroscopy of the 39 kdalton fragment showed that the intermediates lumi-R and meta-Ra are formed like in intact phytochrome or 60 kdalton or 114/118 kdalton fragments. It is discussed that limited proteolysis removed that part of the peptide chain which is responsible for the interaction with the Pfr chromophore but that the site for interaction with the chromophore of Pr and the intermediates lumi-R and meta-Ra is still intact.
Potassium and Rubidium Effluxes in Saccharomyces cerevisiae
Authors: Ortega María D . , Rodríguez-Navarro Alonso 
Published: August 2018

Abstract
In growing cells, K+ and Rb+ effluxes followed first order kinetics, took place with slight differences between K+ and Rb+ and were stimulated at acidic pH values. In uncoupled cells and ATP-depleted cells, K+ efflux was higher than Rb+ efflux. In ATP-depleted cells, the effluxes were not stimulated at acidic pH values. Two different K+ effluxes are proposed: (i) the normal efflux, which may be a K+/H+ antiport and does not function in ATP-depleted cells, and (ii) the backward reaction of the uptake system, which can be high in depolarized cells. The role of the normal efflux system in K+ content and pH regulation is discussed.
Differential Regulation of Two Genes Controlling the Biosynthesis of Isovitexin 7-O-Galactoside in Silene Plants
Authors: Steyns Jan M. 
Published: August 2018

Abstract
The expression of the allelic isovitexin 7-O-glycosylation genes gG (transfer of glucose) and gX (transfer of xylose) was studied in cotyledons, rosette leaves, stem leaves and petals of Silene plants. These studies revealed that gG is expressed in all ontogenetic stages, whereas its allele gX is only expressed in the petals. In the vegetative parts of gX individuals 7-O -xylosylation is replaced by 7-O-galactosylation. The possibility that gX encodes an enzyme activity that catalyzes different reactions in the petals and the vegetative parts resulting in the accumulation of the 7-O-xyloside and the 7-O-galactoside respectively, has been disproved. It is shown that there are two different enzymes catalyzing the biosynthesis of isovitexin 7-O-galactoside. These 7-O -galactosyl-transferase activities differ with respect to heat inactivation, pH optimum , flavone acceptor specificity and Michaelis-Menten enzyme kinetic parameters. The genes controlling these enzyme activities are regulated differentially, with gene O7g (described previously by Steyns et al. [11]), expressed in the cotyledons and the rosette leaves and Xgal in the stem leaves and petals.
Flavin Nucleotide-Dependent 3-Hydroxylation of 4-Hydroxyphenylpropanoid Carboxylic Acids by Particulate Preparations from Potato Tubers
Authors: Boniwell Jeremy M. , Butt Vernon S. 
Published: August 2018

Abstract
Particulate preparations from potato tubers, extracted in 4 mᴍ 2-m ercaptoethanol, catalyze the 3-hydroxylation of 4-hydroxyphenylpropanoid carboxylic acids, including p-coumaric acid and tyrosine, in the presence of NADH (or NADPH) and FAD (or FMN); ascorbate could not substitute for these electron donors. Among a range of 4-hydroxylated C6-C2 and C6-C1 compounds tested, only 4-hydroxyphenylacetic acid and p-cresol were hydroxylated. The hydroxylase was sensitive to KCN and diethyldithiocarbam ate and showed some features of phenolase hydroxylation, but no DOPA oxidase nor chlorogenic acid oxidase activity was exhibited under these conditions. It is suggested that the phenolase complex, which is confined to potato tuber particles, in whole or part catalyzes the hydroxylation.
Properties of Vinorine Synthase — the Rauwolfia Enzyme Involved in the Formation of the Ajmaline Skeleton
Authors: Pfitzner Artur , Polz Leo , Stöckigt Joachim 
Published: August 2018

Abstract
Vinorine synthase, a key enzyme in the formation of the Rauwolfia alkaloid ajmaline and its derivatives, has been isolated from Rauwolfia serpentina cell suspension cultures. The new enzy­me has been 160-fold purified and characterized in detail. The synthase catalyses a single step in the biosynthesis of ajmalan alkaloids by the acetyl-coenzyme A and 16-epi-vellosimine dependent formation of vinorine, which shows the basic ajmaline skeleton. Besides a characteristic substrate specificity the major properties of the enzyme are a relatively high pH optimum (pH 8.5), a temperature optimum of 35 °C, an isoelectric point of pH 4.4, and a relative molecular weight of 31000 ± 8%. The apparent Km values for 16-epi-vellosimine and acetyl-coenzyme A were 19.4 μm and 64 μm resp. for the formation of vinorine. Kinetic data of the catalysed reaction indicate that 17-deacetylvinorine is not involved as a free intermediate during the vinorine biosyn­thesis. Vinorine was proved by in vivo feeding experiments to be the biosynthetic precursor of the alkaloids in the final stages of the ajmaline pathway, vomilenine (21-hydroxyvinorine), 17-O-acetylnorajmaline and 17-O-acetylajmaline.
Partial Purification and Characterization of S-Adenosyl-ʟ-Methionine: Norreticuline N-Methyltransferases from Berberis Cell Suspension Cultures
Authors: Wat Chi-Kit , Steffens Paul , Zenk Meinhart H. 
Published: August 2018

Abstract
Two new N-methyltransferases (NMT-I and NMT-II) were found to occur in Berberis vulgaris cell suspension cultures. One of these enzymes (NMT-I) was partially purified (100-fold) and characterized. This enzyme is specific for tetrahydrobenzylisoquinoline alkaloids and S-adenosyl-ʟ-methionine serves as the methyl donor. The apparent molecular weight of the enzyme is 68,000. The pH optimum of the enzyme is 7.6, the temperature optimum 35 °C. Apparent KM values for (R)-tetrahydropapaverin as substrate were 0.2 mᴍ and for SAM 0.04 mᴍ. The preparation of the same type of enzyme from B. wilsoniae var. subcaulialata was utilized as an efficient enzymatic system for the synthesis of stereochemically pure (R)-as well as (S)-reticuline labelled with tritium or 14C at the N-CH3 group. Enzymes catalyzing this type of reactions are named S-adenosyl-ʟ-methionine: norreticuline N-methyltransferases.
Green Algae (Scenedesmus obliquus) Contain Three Thioredoxins of Regular Size
Authors: Langlotz Petra , Wagner Wolfgang , Follmann Hartmut 
Published: August 2018

Abstract
A comprehensive thioredoxin profile of Scenedesmus obliquus has been established by chromatography of heat-stable protein extracts on five different ion exchange, gel permeation, and affinity chromatography columns and using three different assay systems including homolo­gous S. obliquus ribonucleotide reductase, chloroplast fructose-bis-phosphatase, and NADP malate dehydrogenase. Four different thioredoxins were purified to homogeneity. Besides the large chloroplast thioredoxin f described previously, the algae contain three proteins of molecular weight 12,000 designated thioredoxin I, II, and III. They bind specifically to antibodies against E. coli thioredoxin. Chloroplast-free mutant algae (strain C-2A′) lack thioredoxin f but contain all three regular thioredoxins. Species I and II have very similar amino acid composition and enzyme-stimulating activities. They are considered cytoplasmic thioredoxins which serve as hydrogen donors in algal deoxyribonucleotide biosynthesis. Thioredoxin III is of low activity towards all the presently tested enzymes and its physiological role remains unknown; its role as a glutaredoxin could be excluded. All non-photosynthetic plant cells analyzed so far (mutant algae, seeds, and roots) contain a set of three regular-size thioredoxins.
Changes in Levels of Cellular Constituents in Suspension Culture of Catharanthus roseus Associated with Inorganic Phosphate Depletion
Authors: Ukaji Toshiko , Ashihara Hiroshi 
Published: August 2018

Abstract
Changes in growth and the level of various cellular constituents were monitored for 96 h after transfer of stationary phase cells of Catharanthus roseus to fresh complete (“+Pi”) or phosphate deficient (“-Pi”) Murashige-Skoog medium. In the cultures transferred to “+Pi” medium, cell number and fresh weight increased rapidly after an initial lag period, while little or no increase in cell number or fresh weight was observed in cultures transferred to “-Pi” medium. The levels of ATP, glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), RNA and protein, increased in the cultures in “ + Pi” medium, while the levels of free amino acids decreased. In contrast, we found a decrease in the levels of ATP, G6P and F6P and an increase in the levels of free amino acids in the cultures in “-Pi” medium. Appreciable DNA synthesis was observed only in cells growing in “+Pi” medium, at 72 h after cell transfer. The rate of RNA synthesis in the “+Pi” culture was generally higher than that in the “-Pi” culture. The levels of ethanol soluble-phenolic compounds increased transiently in the cells grown in both media just after cell transfer, but the level in the “+Pi” culture decreased progressively with cell division.
The metabolic role of inorganic phosphate in metabolism of Catharanthus roseus cells is discussed.
C9 Aliphatic Aldehydes: Possible Sex Pheromone from Male Tropical West African Shield Bug, Sphaerocoris annulus
Authors: Gough A. J. E. , Games D. E. , Knight D. W. , Olagbemiro T. O. 
Published: August 2018

Abstract
By gas chromatography-mass spectrometry, 1H NMR , and synthesis of authentic standards, the secretion from the abdominal dorsal scent gland of male adults of Sphaerocoris annulus has been found to contain a mixture of C9 aliphatic aldehydes: nonanal (3%), (Z)-4-nonenal (13%), (E)-4,8-nonadienal (23%) and (Z)-4,8-nonadienal (56%). A further component was tentatively iden­tified as 8-nonenal (5%).