bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and Characterization of Flavonol Converting Enzymes from Mentha piperita Plants and from Mentha arvensis Cell Suspension Cultures
Authors: Frey-Schröder Gudrun , Barz Wolfgang 
Published: August 2018

Abstract
Peroxidases from several plants, including horseradish peroxidase, were capable of converting flavonols to the corresponding 2,3-dihydroxyflavanones in presence of H2O2 . Contrastingly, protein extracts from Mentha piperita plants and Mentha arvensis cell suspension cultures perform ed the same enzymatic step in absence of H2O2 , but only with quercetin, not with kaempferol. H2O2-independent, quercetin converting enzymes were isolated and purified from these extracts, and they could be classified in two groups according to the extent of stimulation of the enzyme reaction by H2O2 . Enzymes from group I were stimulated by exogenous H2O2 , and they resembled horse­ radish peroxidase in several aspects. They possessed IAA oxidase activity, but quercetin was the preferred substrate. Enzymes from group II from the plants appeared to be a distinctly different set of enzymes. They were not stimulated by H2O2 , but required molecular oxygen and converted only 3,3′,4′-trihydroxyflavones under aerobic conditions. Also, they showed no Soret-bands and possessed no IAA oxidase activity. These proteins appear to be a new class of enzymes participating in the first step of flavonol degradation in plants.
On the Oligomycin-Sensitivity and Subunit Composition of the ATPase Complex from Rhodospirillum rubrum
Authors: Miiller Hans Werner , Baltscheffsky Margareta 
Published: August 2018

Abstract
Two alternative procedures for isolation of the oligomycin-sensitive ATPase complex (E. C. 3.6.1.3) from R. rubrum chromatophores are compared with respect to ease, rapidity, and yield.
The inhibitory effect of oligomycin on the membrane-bound Ca2+ -ATPase activity is increased during storage of the chromatophores, whereas the effect of oligomycin on the membrane-bound Mg2+ -ATPase activity does not change within a week.
Oligomycin-sensitivity of the solubilized ATPase complex depends on the isolation procedure.
The enzyme complex consists of at least nine different polypeptides with the apparent molecular weights of (1) 67,000, (2) 60,000, (3) 56,000, (4) 35,000, (5) 22,000, (6) 20,000, (7) 17,000, (8) 12,000, (9) 11,000. The polypeptides 2 - 4, 7, and 8 represent subunits of coupling factor 1.
The Molecular Weight of rRNA Precursor Molecules and Their Processing in Higher Plant Cells
Authors: Seitz Ursula , Seitz Ulrich 
Published: August 2018

Abstract
Actively dividing callus cells of higher plants (Petroselinum crispum, Daucus carota, Acer pseudoplatanus) were used to detect the primary gene product of rDNA in vivo. Parsley and carrot cells were labelled with [32P] orthophosphate. Under non-denaturing conditions, in both cases only one high molecular weight rRNA precursor was present on polyacrylamide gels. Its molecular weight did not exceed 2.5 × 106 dalton. Under denaturing conditions, 2.0 - 2.1 × 106 dalton were determined on formamide gels. This rRNA precursor was already present after a labelling period of 5 -10 min. In parsley cells labelled mature rRNA (25S and 18S) arrived in the cytoplasm 45 min after onset of incubation.
In Acer pseudoplatanus incubated with [3H] uridine two rapidly labelled components did emerge from polyacrylamide gels without formamide; their molecular weights were 2.3 and 3.2 - 3.4 × 106 dalton. After electrophoresis in formamide, the larger component disappeared, thus indicating that it would be an intermolecular aggregate of different for the existence of rRNA precursors exceeding the molecular weight of 2.5 × 106 dalton.
Density-Dependent Growth Adaptation Kinetics in 3T 3 Cell Populations Following Sudden [Ca2+] and Temperature Changes. A Comparison with SV40-3T3 Cells
Authors: Bosch Jürgen van der , Sommer Ilse , Maier Heinz , Rahmig Willy 
Published: August 2018

Abstract
Lowered extracellular [Ca2+] causes low growth rates and low stationary cell densities in 3T3 cell cultures as compared to physiological [Ca2+]. Under otherwise constant conditions the extra­ cellular [Ca2+] determines a stable stationary cell density, which can be readied by increase of net cell number or decrease of net cell number, depending on cell density at the time of [Ca2+] adjustment. SV40-3T3 cells do not show this [Ca2+] dependency. At 39 °C 3T3 and SV40-3T3 cell populations show an increased growth rate at low cell densities as compared to cell populations at 35 °C. Approaching the stationary density the growth rate of both cell sorts is reduced faster at 39 °C than at 35 °C, leading to lower stationary cell densities at 39 °C than at 35 °C. A temperature change from 39 °C to 35 °C or in the opposite direction can affect the stationary cell density of 3T3 cell populations only if applied before reduction of growth rate by density-dependent growth-inhibiting principles has taken place.
Notizen: Isolation of Batatasin I from Dioscorea dumetorum Rhizomes
Authors: El-Olemy M. M. , Reisch J. 
Published: August 2018

Abstract
Batatasin I was shown to occur in the fresh rhizomes of poisonous yam (Dioscorea dumetorum Pax.,). It was isolated by column chromatography and identified by chromatographic and spectral evidence. Two other unknown phenanthrenes were shown to occur by thin-layer chromatography.
Notizen: Phytoalexin Production by Species of the Genus Caragana
Authors: Ingham John L. 
Published: August 2018

Abstract
The fungus-inoculated leaflets of 39 Caragana species have been found to variously produce five isoflavonoid phytoalexins including the known pterocarpan derivatives, medicarpin, maackiain, variabilin and pisatin. Small quantities of a previously undescribed C-methylated pterocarpan were obtained from leaflets of C. acanthophylla.
Notizen: Electron Microscopy of Synaptonemal Complexes in Semithin Sections
Authors: Colman Ondina D. , Stockert Juan C. 
Published: August 2018

Abstract
The technique of osmium tetroxide fixation followed by a treatment with p-phenylenediamine was applied to mouse testes in order to analyze pachytene nuclei. Observation of Epon semithin sections (0.25 - 0.5 μm) in conventional elec­tron microscopy revealed the presence of positively stained synaptonemal complexes surrounded by unstained chromatin. The present results show that by using this method a suitable contrast and resolution can be achieved for semithin sections, which facilitates the topographical study of synaptonemal complexes.
Comparison of the Inhibition of Photosynthetic Reactions in Chloroplasts by Dibromothymoquinone, Bromonitrothymol and Ioxynil
Authors: Reimer S. , Link K. , Trebst A. 
Published: August 2018

Abstract
The inhibition of photosynthetic electron flow in broken chloroplasts by dibromothymoquinone and dibromothymohydroquinone (DBMIBH2) is reversed by dithiothreitol (DTT) as well as by serum albumin. The reversal of DBMIBH2 inhibition by DTT shows a time lag, that of DBMIB only, when chloroplasts and DBMIB had been preilluminated. This is to show that chloroplasts reduce DBMIB and that probably DBMIBH2 is the actual inhibitor species.
Bromonitrothymol, ioxynil and related inhibitory phenolic compounds have a different relation­ ship of inhibitory potency to chemical structure than DCMU and the analogous triazinone herbicide metribuzin but nevertheless inhibit photosynthetic electron flow at the same functional site. This is supported by the finding that labelled metribuzin is displaced from the thylakoid membrane by bromonitrothymol and ioxynil indicating identical binding sites. On the other hand inhibition by the phenolic inhibitors bromonitrothymol and ioxynil but not that of DCMU and metribuzin has a time lag of about 4 min.
Fusion of Plant Protoplasts Induced by a Positively Charged Synthetic Phospholipid
Authors: Nagata Toshiyuki , Eibl Hansjörg , Melchers Georg 
Published: August 2018

Abstract
A newly synthesized phospholipid, 1,2-O-Dipentadecylmethylidene-glycerol-3-phosphoryl-(N-ethyl-amino) -ethanolamine, having positive charge was found to exercise fusion activity on plant proto­ plasts. This phospholipid is not found in cells and has an unusal chemical structure with a dioxolane ring. Some properties of this compound are discussed in relation to phospholipid-induced cell fusion.
Antimicrobial Activity of Quaternary Ammonium Salts of Some Saturated Heterocycloalkyl Amines [1]
Authors: Lacko Ivan , Devínsky Ferdinand , Krasnec Ľudovít , Mlynarčik Dušan 
Published: August 2018

Abstract
N,N-Dialkyl Ammonium Salts of Saturated Heterocyclic Amines, Antimicrobial Activity Antimicrobial activity of N-alkyl-N-dodecylpiperidinium bromides and N-ethyl-N-dodecylheterocycloalkyl ammonium bromides (pyrrolidine, morpholine, perhydroazepine) deter­ mined on grampositive and gramnegative bacteria, yeasts and moulds, presented as minimum inhibition concentration (MIC). Comparison of the effect of change of structure: lenghtening of alkyl chain, change of heterocyclic ring. Change in the lenght of alkyl chain markedly affects the antimicrobial activity, change of heterocyclic ring has no substantial effect. The most active compounds were N-heptyl-and N-hexyl-N-dodecylpiperidinium bromides.
Studies on the Chemistry of Lichens, XIX. New Amino Compounds from Anaptychia fusca and Several Stereocaulon Species
Authors: Solberg Yngve 
Published: August 2018

Abstract
The lichen Anaptychia fusca and several Stereocaulon species have been chemically investigated with regard to their content of unknown ninhydrin-positive com pounds. New aliphatic and alicyclic, amino components isolated from water extracts of these lichen species have been characterised as aminopentitol, am inohexitol and aminocyclitetrol. To our knowledge, this is the first time that com pounds such as these have been found in lichen material. Aminopentitol and amino­ cyclitetrol appear to be characteristic constituents of Anaptychia fusca, whereas aminohexitol has been found in several species of Stereocaulaceae.
γ-Bestrahlte Ribosomen von Micrococcus radiodurans in einem System der zellfreien Proteinsynthese / γ-Irradiated Ribosomes from Micrococcus radiodurans in a Cell-Free Protein Synthesizing System
Authors: Süssmuth Roland , Widmann Annette 
Published: August 2018

Abstract
γ-irradiation inactivation of isolated ribosomes of Micrococcus radiodurans was studied by ex amining poly U directed synthesis of polyphenylalanine. Ribosomes of M . radiodurans did not show significant y-radiation sensitivity up to a dose of approx. 11.6k Gy. Cells of M . radiodurans take up more magnesium than E. coli cells unter the same conditions. The magnesium content of ribosomes of M . radiodurans was 18% higher than that of E. coli ribosomes. A possible relation between Mg2+-content and γ-resistance is discussed.
On the Analysis of Competitive Binding of Various Ligands to Cooperative and Independent Binding Sites of Macromolecules
Authors: Kalbitzer Hans Robert , Stehlik Dietmar 
Published: August 2018

Abstract
The paper deals with the practical evaluation of multiple binding equilibria of macromolecules and different ligands competing for the same binding sites. The necessary formalism is reviewed and set up for the equilibria involving a macromolecule with various classes of independent binding sites and/or a class of cooperative sites and up to three different ligands in competition for them. In particular, it was necessary to extend the Hill approximation to treat simultaneous competition for cooperative as well as independent binding sites, while earlier at­tempts are shown to be inadequate.
Criteria are developed for a qualitative analysis of complex binding patterns using the Scatchard-plot of the experimental data in order to obtain a model of the binding structure and an adequate set of input parameters for the numerical analysis. Numerical examples refer to the binding of calcium and magnesium to the sarcoplasmic reticulum as studied by competitive re­placement of manganese ions [3].
High Sensitivity in CID Mass Spectrometry, Structure Analysis of Pyrolysis Fragments
Authors: Louter G. J. , Stalmeier P. F. M. , Boerboom A. J. H. , Haverkamp J. , Kistemaker J. 
Published: August 2018

Abstract
Collision Induced Dissociation (C ID),C ollisional Activation (CA), Pyrolysis, Mycobacterium, Mass Spectrometry An apparatus is described for Collision Induced Dissociation Mass Spectrometry, where es­ sential increase in sensitivity in the detection of the fragment spectrum is obtained by simultaneous detection. Decrease in resolution due to kinetic energy release on dissociation is prevented by post-acceleration of the fragment ions.
The instrument was used to investigate the structure of the mass m/z= 59 com pound in the pyrolysis products of Mycobacterium cells. This mass is a key mass in the pyrolysis mass spectrometric identification of dangerous mycobacterial strains.
Insulin und Glukagon im Blutplasma teilhepatektomierter Ratten / Insulin and Glucagon in the Blood Plasma of Partial Hepatectomized Rats
Authors: Strecker Wolf , Silz Siegfried , Ruhenstroth-Bauer Gerhard , Böttger Ingolf 
Published: August 2018

Abstract
Up to 4 weeks after partial hepatectomy the concentrations of immunoreactive insulin and glucagon in the blood plasma of rats were determined. Furtherm ore we m easured the activity of acid phosphatase in the serum, the concentration of cyclic AMP in liver cells, the activities of acid phosphatase in whole liver cells and in the cytosol of liver cells after partial hepatectomy.
2 h after partial hepatectom y there was a decline of the concentration of insulin in the plasm a to about 13% of the initial value. 12 h after surgery a 5-fold increase of glucagon was found in the plasma. Shortly after this cyclic AMP reached its highest concentration.
The activity of acid phosphatase in the whole liver cells and in the cytosol decreases slightly in the first 24 h after surgery whereas there is an increase of the activity of acid phosphatase in the serum.
Effect of 5-Aza-2′-deoxycytidine on Antibody Formation and DNA Synthesis in Rat Spleen
Authors: Čihák A. , Madar J. , Veselý J. 
Published: August 2018

Abstract
5-Aza-2′-deoxycytidine which is preferentially taken up by the lymphatic tissue and is in­ corporated into D NA strongly affects the ability of the immune system to synthesize IgG anti­ bodies against sheep red blood cells without affecting IgM antibody formation. A single dose of the drug results in a prolonged inhibition persisting 14 days after the secondary immunization. The inhibitory effect is dose-dependent and is maximal when 5-aza-2′-deoxycytidine is given 2 days after sheep erythrocytes. The drug affects the utilization of thymidine for the synthesis of DNA in the spleen; under certain conditions the enhancement of the rate of DNA synthesis in the spleen has been observed.
Separation of Alphavirus Nucleocapsids from Envelope Fragments
Authors: Enzmann P.-J. , Weiland F. 
Published: August 2018

Abstract
Methods for the preparation of alphavirus nucleocapsids and envelope fragments for bio­ chemical, electron microscopical and serological investigations are described. Difficulties which have been encountered previously in attempts to isolate viral nucleocapsids for morphological studies, namely disruption of the fragile particles, have been overcome by treatment with formaldehyde.
A High Potential Iron Sulfur Protein of the Purple Sulfur Bacterium Thiocapsa roseopersicina
Authors: Fischer Ulrich 
Published: August 2018

Abstract
Thiocapsa roseopersicina, High Potential Iron Sulfur Pro­ tein (HIPIP), Phototrophic Bacteria High potential iron sulfur protein (HIPIP) from the purple sulfur bacterium Thiocapsa roseopersicina was isolated in the oxidized and reduced form by DEAE-and Sephadex column chromatography (best purity index A 282 nm red/A 385 nm red. = 3.78). The enzyme contains non-heme iron and acid-labile sulfide in an equimolar ratio. The enzyme shows no aconitase activity.
Method for the Selective 2′-O-Substitution of Nucleosides
Authors: Sauer C. , Schwabe U. 
Published: August 2018

Abstract
This paper presents a new method for selective reactions of predetermined sugar hydroxyls of nucleosides. Suc-cinylated nucleosides were investigated as examples for the use of the cyclic phosphate group for protecting purposes. Starting from cyclic AMP the 2′-O-group was selectively succinylated yielding 93% 2′-O-succinyl cyclic AMP. The cyclic phosphate was enzymatically dephosphorylated in a one step procedure under neutral conditions and 2′-O -succinyl adenosine containing a small amount of the 3′-O-isomer was produced in 91% yield. When establishment of equilibrium of the 2′-O-and 3′-O-isomers was allowed, 54% yield of crystallized 3′-O-succinyl adenosine was prod­ uced. The results suggest that the easily accessible cyclic monophosphates are good protecting groups for the pro­ duction of nucleoside derivatives, especially at the 2′-O-position under neutral conditions.
Tectorigenin, a Phytoalexin of Centrosema haitiense and Other Centrosema Species
Authors: Markham K enneth R. , Ingham John L. 
Published: August 2018

Abstract
A phytoalexin isolated from the fungus-inoculated leaflets of Centrosema haitiense, C. pubescens (3 accessions) and C. virginianum has been identified as 5,7,4′-trihydroxy-6-methoxy-isoflavone (tectorigenin). This compound is variously accompanied by other isoflavones includ­ ing the previously described phytoalexin, cajanin (5,2′,4′-trihydroxy-7-methoxyisoflavone). Sub­ stantial quantities of aesculetin were obtained when C. haitiense leaves were submerged for 48 h in water or fungal spore suspensions. The taxonomic position of Centrosema within the legume tribe Phaseoleae is discussed.
Enzymatic Preparation of 14C-Labeled Phytoene, Squalene, and Geranylgeranyl Pyrophosphate from [2-14C]Mevalonic Acid
Authors: Sandmann Gerhard , Hilgenberg Willy , Böger Peter 
Published: August 2018

Methods are described for an enzymatic preparation of 14C-labeled terpenoids. With a cell-free system of a white mutant of Phycomyces blakesleeanus (Mucoraceae) [14C]squalene and [14C- cis]phytoene can be synthesized from [2-14C]mevalonate. The application of norflurazon, a phenyl- pyridazinone herbicide, helps to increase the yield of squalene. Furthermore, the liquid endosperm of Echinocystis lobata (Cucurbitaceae) was used for the formation of either [14C(-)]kaurene from [14C]mevalonic acid or [14C-/ra/w]geranylgeranyl pyrophosphate in the presence of Amo 1618.
The hydrocarbons formed were purified by alumina-column chromatography and preparative thin-layer chromatography (TLC). Geranylgeranyl pyrophosphate was separated by DE-column chromatography followed by TLC.
Effects of ʟ-Methionine-S-sulfoximine on Growth and Glutathione Synthesis in Tobacco Suspension Cultures
Authors: Rennenberg Heinz , Uthemann Rolf 
Published: August 2018

Abstract
Tobacco cells grown photoheterotrophically with high ammonium and sulfate concentrations are able to cope with small amounts of methionine-sulfoximine. The observed methionine-sulfoximine tolerance of tobacco suspensions is due to an extracellular glutathione and an intra­ cellular glutamine reservoir, both reservoirs are considerably reduced by treatment with methionine-sulfoximine concentrations that do not affect the growth of the cells. In tobacco suspension cultures grown with nitrate as sole nitrogen source that do not contain high amounts of glutathione and glutamine, growth inhibition by methionine-sulfoximine can be prevented by addition of these substances to the growth medium. These data indicate that synthesis of glutathione and glutamine are both inhibited by mentionine-sulfoximine; furthermore they show evidence that - in contrary to animal cells -the whole glutathione molecule is taken up by tobacco cells. Synthesis of glutathione from the consisting amino acids is inhibited by methionine-sulfoximine in crude cell homogenates to a similar extent than observed in tobacco suspensions in vivo; therefore, the activity, and not the amount of enzymes of glutathione syn­ thesis seems to be reduced by treatment with methionine-sulfoximine. As tobacco suspensions are able to recover from methionine-sulfoximine treatment with respect to accumulation of glutathione in the medium as well as with respect to growth, detoxication of methionine-sulf­ oximine has to be assumed.
Sinapine Esterase. II . Specificity and Change of Sinapine Esterase Activity During Germination of Raphanus sativus
Authors: Strack Dieter , Nurmann Gerhild , Sachs Gesine 
Published: August 2018

Abstract
Following a 20 to 24 h lag-phase after sowing, the onset of both rapid degradation of sinapine (sinapolycholine) and rapid increase in sinapine esterase activity in cotyledons of Raphanus sativus was observed. After 2 days of germination maximal enzyme activity was reached and declined in subsequent germination stages as rapidly as it had appeared. Esterases, active against indophenyl acetate, showed highest activity in dry seeds, declining to more than 50% between the 1st and 3rd day of germination.
Starch gel electrophoresis showed that all protein extracts contained a multiplicity of esterases, active against α-naphthyl acetate. When gels were incubated with sinapine, one new band appeared, stainable with diazotized ρ-nitroaniline. This band represents sinapine esterase activity. Tests for substrate specificity towards cinnamic acid choline esters showed highest enzyme activity with sinapine.
Studies on the occurrence of sinapine esterase in other Brassicaceae revealed that the enzyme activity coincides with the occurrence and degradation of sinapine.
In vivo und in vitro Hydroxylierung von Androgenen in Ratten nach Leberschädigung und Nahrungskarenz / In vivo and in vitro hydroxylation of testosterone and dihydrotestosterone in rats after liver damage and starvation
Authors: Wenzel Martin , Lemm Ursula 
Published: August 2018

The in vivo C-2-hydroxylation of testosterone and 5-dihydrotestosterone in rats was measured by labilisation of tritium as HTO after injection of [1α, 2α-T]testosterone or [1 α, 2α-T]5α-dihy- drotestosterone (radiospirometry).
After experimental liver damage caused by CCl4 or after starvation for 60 h the hyroxylation of the androgens decreased. Similar results were gained by measuring the C-2-hydroxylation of testosterone, 5 α-dihydrotestosterone and estradiol.
Modulation of Amino Acid Transport in Rat Liver Slices by Tissue Preincubation
Authors: Ehrhardt Volker 
Published: August 2018

In rat liver slices, a prolonged preincubation resulted in a stimulation of AIB and alanine uptake. The increase of transport of both amino acids can be ascribed to a reduction of Kt without an alteration of Vt.
The enhancement of transport seems to be restricted to the A mediation as indicated by the findings that only the Na+-dependent, MeAIB-inhibitable portion of AIB transport was increased by the prolonged preincubation, and, furthermore, that the uptake of cysteine, a specific substrate for system ASC in liver cells, was not affected.
The effect of an extended preincubation on AIB transport was abolished by the addition of high concentrations of AIB and alanine to the preincubation medium. Several other amino acids tested did not affect the increase of AIB transport.
The observed stimulation of transport seems not to be due to the derepression of the synthesis of transport proteins, as cycloheximide and 5-azacytidine did not block the increase of AIB uptake.
The enhancement of amino acid transport does not appear to be a result of a release from transinhibition since the uptake of alanine was markedly enhanced after 3 h of preincubation while the alanine concentrations in the incubated liver slices did not change significantly.