bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immobilization of Erythrocytes by Radiation Polymerization of Glass-Forming Monomers at Low Temperatures
Authors: Yoshii Fumio , Kaetsu Isao , Yamada Akio 
Published: August 2018

Abstract
The immobilization of erythrocyte as the whole cell without hemolysis was studied. It found that erythrocyte could be treated and immobilized stably by radiation polymerization of specific monomers having high viscous and long oxyethylene units chain such as methoxypolyethylene-glycol methacrylate (M-23G) and polyethyleneglycol dimethacrylate (14G). Irradiation dose without hemolysis was limited less than 1 × 105 r and a comonomer system consisting of M -23G-14G, 1:1 and small quantity of glutaraldehyde (GA) was the optimum carrier composition. The functional properties of the immobilized erythrocyte was also investigated. It was found that the immobilized cell could be carried out carbon monoxide-oxygen gas exchange effectively and reversibly so as in the intact cell. The immobilized erythrocyte also showed the catalase activity just as in the intact cell. The stability of erythrocyte increased greatly by the immobilization for standing at low and room temperatures and hardly hemolyzed in non-isotonic medium such as pure water. It was observed in scanning electron microscope that the immobilized erythrocyte had a hollow disk shape same as in intact cell and covered with a thin polymer layer.
High Perform ance Liquid Chrom atographie Analysis o f Steroidal Saponins from Avena sativa L
Authors: Kesselmeier J. , Strack D. 
Published: August 2018

Abstract
Reversed phase high performance liquid chromatography offers an efficient and rapid method for analysis of steroidal saponins. Crude extracts from primary leaves of Avena sativa and isolated etioplasts therefrom have been resolved into four saponins (avenacosides) using a water-acetonitrile gradient system on RP-8 and monitoring the column effluent at 200 nm with an UV-detector. Detectability was found to be in the range of 50 ng avenacoside B and the detector response was linear up to 8 μg tested. The described method is applicable to studies on localization and physiology of Avena saponins during development of the primary leaf.
Is there an Equilibrium between A scorbic and Dehydroascorbic Acids ?
Authors: Kalus Werner H. , Filby William G. 
Published: August 2018

Abstract
The previously reported interaction between ascorbate monoanion and dehydroascorbic acid yielding semidehy-droascorbic acid has been shown to be therm odynamically unfeasible and non-existent. No evidence for radical formation in the reinvestigation of the reaction using ESR spectroscopy under careful exclusion of air could be found. Our results show that the detection of the free radical in earlier studies resulted from the reaction of ascorbate with traces of oxygen and/or metals.
Radiation D am age to Polypeptides and Proteins in the Solid State, II* Radiolysis of Poly-ʟ-Glutamic Acid
Authors: Söylemez T. , Baumeister W. , Herbertz L. M. 
Published: August 2018

Abstract
For the transformation of glutamic acid into α-amino-butyric acid upon irradiation a decarboxylation mechanism involving the formation of CO2 has been proposed previously. Here we present further experimental evidence in favour of this mechanism. A dditionally the formation of CO as a decarboxylation product has been detected; a radical anion mechanism for its formation is proposed.
Life Cycle of Sarcocystis between Poikilothermic Hosts. Lizards are Intermediate Hosts for S. podarcicolubris sp. nov, Snakes Function as Definitive Hosts
Authors: Matuschka Franz-Rainer 
Published: August 2018

Abstract
The role of the Western Whip snake Coluber viridißavus was demonstrated as a definitive host for Sarcocystis podarcicolubris sp. nov. of the Italian Wall lizard Podarcis sicula and the Tyrrhenian Wall lizard Podarcis tiliquerta. Sporocysts (9.58 x 6.94 μm) of S. podarcicolubris from a naturally infected snake C. viridißavus were fed to a Sarcocystis free lizard P. sicula and via arthropods Musca domestica to another Sarcocystis free lizard P. tiliquerta. About 3-4 months later sarcocysts could be detected in both lizards. The cysts measured 90-130 μm × 450-550 μm. The cyst wall had 2.5-3 μm long villus like protrusions. The sausage-shaped bradyzoites measured circa 7.7 × 2 μm. Refeeding of the experimentally infected lizards to the snake led to a renewed shedding of sporocysts after a prepatency of 12 -15 days.
Incorporation of [14C]Phenylalanine and [14C] Cinnamic Acid into Leaf Pieces and Mesophyll Protoplasts from Oat Primary Leaves for Studies on Flavonoid Metabolism at the Tissue and Cell Level
Authors: Proksch Margareta 
Published: August 2018

When the abaxial epidermis was peeled from 5 to 6 day old oat primary leaves, and 3 cm segments were floated on radioactive phenylalanine or cinnamic acid solutions, more than 90 per cent of the radioactivity was incorporated within 3 to 7 h depending on the developmental stage of the leaf. C-glycosylflavones were labelled within 15 min and radioactivity in these compounds increased for several hours. Pulse labelling and pulse chase experiments with either phenylalanine or cinnamic acid, unequivocally demonstrate that oat flavones are stable end products of metabolism. However, this procedure does not distinguish between sequential biosynthesis of various flavones and their interconversion. Cinnamic acid was more efficiently (ca. 20 x) converted into oat leaf flavones than was phenylalanine, when the precursor was fed to leaf pieces, and flavones recovered from mesophyll protoplasts. Different labelling patterns were obtained with whole leaf segments and protoplasts which apparently reflect differences in tissue specific flavone biosynthesis of mesophyll and epidermis.
Isolated mesophyll protoplasts incubated with [14C]cinnamic acid synthesize 14C-labelled flavones characteristic of the mesophyll, as well as several unidentified phenylpropanoid derivatives not found in the intact tissue. Data suggest that photosynthetically active mesophyll cells are a main site of tissue specific flavone biosynthesis
Partition of Phylloquinone Kx between Digitonin Particles and Chlorophyll-Proteins of Chloroplast Membranes from Nicotiana tabacum
Authors: Interschick-Niebler E. , Lichtenthaler H. K. 
Published: August 2018

The partition of phylloquinone (vitamin K1), of chlorophylls a and b and of the two main carotenoids, β-carotene and lutein, in subthylakoid particles (digitonin treatment) and chlorophyll protein complexes (sodium dodecylsulfate polyamide-gel electrophoresis) isolated from tobacco chloroplasts (Nicotiana tabacum L.) is described.
1. The “light particle” fractions (S 90 000, S 150 000) of digitonin fragmented chloroplasts are enriched in CP I and contain a higher proportion of phylloquinone, chorophyll a and β-carotene as compared to whole chloroplasts. This is visualized by high values for the ratio a/b (6 -8) and for β-carotene/lutein (1.7) as well as about 3 mol of K1 per 100 mol of total chlorophyll.
The “heavy digitonin particle” fraction (10 000 x g sediment), in turn, contains a higher proportion of chlorophyll b and lutein, but a lower level of phylloquinone than whole chloroplasts.
2. The chlorophyll a-protein CP I of pigmentsystem I, isolated by preparative gel electrophoresis using 0.5% and 4% SDS, is characterized by a stable level of phylloquinone (1 mol K1 per 100 mol of total chlorophyll), high chlorophyll a/b ratios (7 -10) and high values for β-carotene/lutein (~ 6.0).
The light-harvesting chlorophyll a/b-protein LHCP of photosystem II (chlorophyll a/b = 1.1 - 1.5, β-carotene/lutein = < 0.1) contains either low amounts of phylloquinone (0.5% SDS) or only trace amounts of K1 (4% SDS).
The free pigment fraction (FP) contains at 0.5% SDS 57% of the total phylloquinone of thylakoid membranes. At 4% SDS the K1 amount in the free pigment fraction increases to 84%.
3. The phylloquinone partition studies in digitonin particles and SDS chlorophyll proteins indicate that there exist at least two localization sites for phylloquinone K1 in the photosynthetic membrane. The CP I complex and a second site, presumably near photosystem II (CPa?)
Radioactively Labelled Phytic Acid from Maturing Seeds of Sinapis alba
Authors: Blaicher F. Michael , Mukherjee Kumar D. 
Published: August 2018

Abstract
Maturing seeds of Sinapis alba were incubated with D-[U-14C]glucose, sodium [l-14C]acetate or m>>O[U-14C]inositol in order to prepare radioactively labelled phytic acid with high specific activity. Although each substrate was utilized for the biosynthesis of phytic acid, maximum incorporation of radioactivity into phytic acid was found with rayoinositol. Radiochemical purity of the [U-14C]phytic acid preparations was confirm ed by chromatographic techniques. Such preparations should be useful for the study of interaction of phytic acid with metal ions and proteins and may serve as substrate in the assay of phytase.
Genetic Control of Flavanone 3-Hydroxylase Activity and Flavonoid 3′-Hydroxylase Activity in Antirrhinum majus (Snapdragon)
Authors: Forkmann G. , Stotz G. 
Published: August 2018

Abstract
In flower extracts of defined genotypes of Antirrhinum majus, two different hydroxylases were found catalysing the hydroxylation of naringenin and eriodictyol in the 3-position and of naringenin in the 3′-position. The 3-hydroxylase is a soluble enzyme and belongs according to its cofactor requirement to the 2-oxoglutarate-dependent dioxygenases. Investigations on different genotypes revealed a clear correlation between block of the anthocyanin pathway by recessive alleles of the gene inc and a complete lack of 3-hydroxylase activity. Chemogenetic studies on different genotypes suggested that the 3′-hydroxyl group of the B-ring of flavonoids is introduced at the stage of C15 intermediates. The corresponding 3′-hydroxylase was found to be localized in the microsomal fraction and required NADPH as cofactor. In confirmation of the chemogenetic studies, a strict correlation was found between 3′-hydroxylase activity and the gene eos which is known to control the hydroxylation of flavones, flavonols and anthocyanins in the 3′-position. These results are similar to those previously obtained with Matthioia incana.
Chromophore Content and Molar Absorptivity of Phytochrome in the Pr Form
Authors: Brandlmeier Thomas , Scheer Hugo , Rüdiger Wolfhart 
Published: August 2018

Abstract
Quantitative absorption spectra in the visible and UV region were recorded for denaturated phytochrome (P r) and phytochromobilin peptides in comparison with native Pr. The method was tested with C-phycocyanin from Spirulina platensis. Based on known molar absorptivities for denaturated phycocyanin and suitable model compounds, and on the ratio A620
native/A655-665
degraded = 2.9, ^native was determined to be 102000 m-1 cm-1 for one phycocyanobilin chromophore in native phycocyanin. Likewise, Native was calculated to be 19000 M-1 cm-1. The corresponding ratios for Pr were Anative/Adenatured = 3.4 and Anative/Adegraded = 3.7, this yielded ε665
native = 109000 to 118000 and ε380
native = 36000 M-1 cm-1 for phytochromobilin in native P r. This value corresponds to one phytochromobilin per small phytochrome (60000 D) if data from the literature are corrected for the content of colorless proteins. The latter has been asessed from (i) the purity index (A280/A665) and (ii) the contribution of the phytochromobilin chromophore at 280 nm as derived from model compounds.
X-Ray Crystal Structure Analysis of Factor A (2-Methyladeninyl-cyanocobamide), a Native Vitamin B12-Analogue
Authors: Kopf Jürgen , Deuten Klaus von , Bieganowski Rainer , Friedrich Wilhelm 
Published: August 2018

Abstract
Vitamin B12-factor A (2-Methyladeninyl-cyanocobamide), Vitamin B12, X-Ray Crystal Structure Analysis The crystal and molecular structure of 2-methyladeninyl-cyanocobamide (factor A) has been determined. This compound crystallizes in space group P21212, with a = 2630.6 (15), b = 2210.6 (13) and c = 1592.1 (9) pm. The structure has been solved by the heavy-atom method and refined by least-squares methods on the basis of 3682 X-ray counter data to R = 0.166 and R w = 0.148. As far as we know, this is the first X-ray-investigation of a purine-corrinoid, which differs from cyanocobalamin (vitamin B12) by containing a purine base instead of 5,6-dimethylbenz-imidazole. The structure analysis of 2-methyladeninyl-cyanocobamide shows unambiguously, that the purine base coordinates with cobalt via N B9. The choice of N B9 as coordinative atom can be ascribed partly (or mainly?) to steric influences, since coordination via N B3, which was also discussed, would presumably lead to severe distortion of the nucleotide loop.
Dryopterin, ein neuartiges C17-Flavan aus Dryopteris filix-mas / Dryopterin, a Novel C17-Flavan from Dryopteris filix-mas
Authors: Karl Christian , Pedersen Peter Alsted , Müller Gerhard 
Published: August 2018

Abstract
Dryopteris filix-mas (L.) Schott, Polypodiaceae, Flavan, Dihydrocoumarin, Lactone From acetone extracts of fresh aerial parts of Dryopteris filix-mas (L.) Schott a flavan-3-ol was isolated. Its structure was elucidated as 5-(3,4-dihydroxyphenyl)-3,3a,4,5-tetrahydro-4,8-dihydro-xy-2H-pyrano[4,3,2-ife]-l-benzopyran-2-one by means of spectroscopic methods including l3C-NMR.
Multifunctional Mode of Action of Substituted Nitrodiphenylethers in Scenedesmus Cells
Authors: Sandmann Gerhard , Lambert Rolf , Böger Peter 
Published: August 2018

Abstract
Nitrodiphenylethers substituted with Cl, CF3, and other comparatively simple substituents are compared with respect to their primary effects on the photosynthetic apparatus. These are direct electron-transport inhibition, energy-transfer inhibition (of ATP synthesis), and pigment bleach­ ing, the latter accompanied by decrease of electron transport activity. Certain substituents and their positions at the diphenylether skeleton can be correlated with a particular influence on these phytotoxic effects. The unicellular alga, Scenedesmus, is an appropriate species to fumisch quantitative data on these primary herbicidal modes of action within a 24-h assay period.
Polymethylated Flavonols of Chrysosplenium americanum I. Identification and Enzymatic Synthesis
Authors: Collins F. W. , De Luca Vincenzo , Ibrahim Ragai K. , Voirin Bernard , Jay Maurice 
Published: August 2018

Abstract
Polymethylated Flavonols, Identification, Enzymatic Synthesis, O-Methyltransferase, Chrysosplenium americanum, Saxifragaceae The major flavonoid constituents of Chrysosplenium americanum (Saxifragaceae) were identified by UV-, NMR-and mass spectroscopy and the analysis of their hydrolytic products. They consisted of two 2'-O-β-D-glucosides of partially methylated 2'-hydroxyquercetin and four 5'-O-β-D-glucosides of partially methylated 6-hydroxyquercetin (quercetagetin).
The O-methyltransferase system of this tissue can catalyse the stepwise O-methylation of quercetin, but not quercetagetin, to its 3,7,4'-triOMe-dervative. It is postulated that the latter compound may serve as a branching-point intermediate in the biosynthesis of the naturally occurring O-methylated flavonols of this tissue.
Interactions between Tryptophan Synthase from Escherichia coli and Derivatives of the Coenzyme Pyridoxal 5'-Phosphate
Authors: Merkl Inge , Balk Hubert , Bartholmes Peter , Jaenicke Rainer 
Published: August 2018

Abstract
The interaction of the coenzyme analogues pyridoxal (A), pyridoxine 5'-phosphate (B), pyridoxic acid 5'-phosphate (Q and N-phosphopyridoxyl-L-serine (D) with both the isolated apo β2 subunit and the native < x2 apo β2 bienzyme complex of tryptophan synthase from Escherichia coli has been investigated using enzyme kinetics and CD spectroscopy. A 500-fold molar excess of (A) yields a maximum activation of the a2 apo β2 complex of 12% compared to the native holo bienzyme complex. The corresponding Michaelis constant KM equals 0.16 mM. Compounds (B -D) which lack the reactive carbonyl group in the 4-position cannot act as cofactor during enzymic turnover. However, they are competitive inhibitors with respect to the natural coenzyme pyridoxal 5'-phosphate. The corresponding inhibition constants K\ are for (B): 0.10 mM, (C): 0.03 mM and (D): 0.16 mM.
The CD spectra of the aromatic side chains of both protein species ([@]278nm for the β2 subunit = 26 degr cm2 decimol-1, for the bienzyme complex = 40 degr cm2 decimol-1) remain un­ changed and no measurable dichroic absorption is induced in the visible region at 415 nm upon addition of (A), (at this wavelength productive binding of pyridoxal 5'-phosphate induces a significant extrinsic Cotton effect in the internal aldimine). Reaction with (B) leads to an enhancement of the dichroic amplitude at 278 nm of the isolated β2 subunit {A[6] = 6 degr cm2 decimol-1) and of the a2 β2 complex (zl[0] = 17 degr cm2 decimol-1) respectively. Com­ pound (C) shows no effect in the aromatic region of the β2 subunit, but a decrease in the a2 β2 complex (A[0) = 5 degr cm2 decimol-1). At 315 nm, however, a remarkable extrinsic Cotton effect of + 20 degr cm2 decimol-1 is induced in (Q . Ligand (D) causes a similar increase at 278 nm of A[0] = 14 degr cm2 decimol-1 in both protein species. The given data are discussed on the basis of the mode of binding of the natural coenzyme.
In Vitro Biosynthesis of the Plant Sulpholipid: On the Origin of the Sulphonate Group
Authors: Hoppe Willi , Schwenn Jens D. 
Published: August 2018

Abstract
Biosynthesis of the plant sulpholipid (diacylsulphoquinovosyl glycerol) has been demonstrated in a cell-free assay system from the green alga Chlamydomonas reinhardii CW 15. The sulpholipid was labelled with [35S]sulphate when ATP, Mg2+ and a reductant were provided. Unlabelied cysteic acid failed to suppress the labelling of the sulphonate group in the lipid. Labelling with [35S]PAPS or [35S]sulphite has been studied in a fractionated cell extract. Sulphite as a precursor only required a particulate fraction of the cell while with PAPS the assay had to be complemented with a soluble protein and a thiol compound. [35S]PAPS was incorporated into the diacylsulphoquinovosyl glycerol with a higher specificity than sulphite.
Pyropheophytin a Accompanies Pheophytin a in Darkened Light Grown Cells of Euglena1
Authors: Schoch Siegrid , Scheer Hugo , Schiff Jerome A. , Rüdiger Wolfhart , Siegelman Harold W. 
Published: August 2018

Abstract
Chromatography Light-grown non-dividing cells of Euglena gracilis Klebs var. bacillaris Cori form pheophytin a like pigments from chlorophyll a without loss of viability when they are allowed to incubate in darkness without shaking. This is accompanied by the loss of long-wavelength components in the red absorption band of intact cells. After extraction of these cells with acetone, transfer of the pigments to ether and treatment of the ether solution with dilute acid, two pigments can be separated by high performance liquid chromatography on reverse phase silica gel (RP-8) using methanol: water = 95:5 (v/v) as the eluting solvent: In addition to pheophytin a, the eluate contains an unknown pigment. With increasing times of incubation of the cells in darkness, the proportion of pheophytin a decreases and the proportion of the unknown increases suggesting, that the unknown is formed from pheophytin a. This pigment has been identified as pyropheophytin a. It has the same absorption spectrum as pyropheophytin a (prepared by pyridine pyrolysis of pheophytin a) and contains phytol as the longchain esterifying alcohol. On conversion to the methyl ester, the resulting methyl phorbide is identical with authentic pyromethylpheophorbide a by tic, hplc, absorption, absorption difference and mass spectros­ copy. This is the first report of pyropheophytin a or any pyrochlorophyll derivative from plants or oxygenic plant-like microorganisms where it may serve as an intermediate in chlorophyll degradation.
Mode of Inhibition of Photosynthetic Electron Transport by Substituted Diphenylethers
Authors: Draber W. , Knops H. J. , Trebst A. 
Published: August 2018

Abstract
Several substituted diphenylethers were found to be effective inhibitors of photosynthetic electron flow in isolated thylakoid membranes from spinach chloroplasts. T heir site of inhibition was localized with artificial acceptor and donor systems. The phenylether of an alkyl substituted nitrophenol is prim arely inhibiting electron flow after plastoquinone function whereas a dinitro-phenylether of a phenyl substituted nitrophenol is inhibiting before plastoquinone function. Therefore certain diphenylethers interfere with plastoquinone function at the oxidation or reduction site, depending on the substitution.
Nonlinear Polarisationoscillations in a Biophysical Model-System I: Internal Dynamics
Authors: Kaiser F. , Szabo Z. 
Published: August 2018

Abstract
To describe a metastable electrical dipole state in a biological system. Fröhlich suggested a nonlinear model potential. In this paper we investigate a system of two such dipoles coupled by a dipole-dipole interaction. M athem atically this model is described by two coupled nonlinear differential equations. In the investigation of the dynamics of the system we distinguish three solution types of the equations of motion.
Die Anfangsphasen des durch Steringlucoside und Indol-3-essigsäure stimulierten Wachstums bei Avenakoleoptilen / Initial Phases of Growth Induced by Sterylglucosides and Indole-3-acetic Acid in Avena Coleoptiles
Authors: Tietz Amo 
Published: August 2018

Abstract
The initial phases of growth induced by sterylglucosides were investigated by means of a high resolution recording technique. Avena coleoptile segments were preincubated with 10-6 M IAA in buffered solution, then the β-vglucosides of sitosterol, stigmasterol, campesterol, and cholesterol respectively were added in the concentration range from 10-7 –10-6 m . It could be demonstrated that the first response to the applied sterylglucosides is a reduction of the growth rate lasting about 15 min, followed by a sharp increase of the growth rate. As the growth response of the coleoptiles after treatment with sterylglucosides is very similar to that observed after application o f IAA alone, it is concluded from the results that sterylglucosides or sterols may also exhibit their primary action at the membrane level, perhaps by influencing microviscosity of the membrane and/or H +-secretion.
Direkte allosterische Wechselwirkung von Sauerstoff und Bicarbonat: N-Acetyl-Ala-Ser-Phe, die N-terminale Sequenz der β-Ketten der Hämoglobine des Nilkrokodils (Crocodylus niloticus) und des Mississippi­ krokodils (Alligator mississippiensis) / Direct Allosteric Interaction of Oxygen and Bicarbonate: N-Acetyl-alanyl-seryl-phenylalanine, N-Terminal Sequence of the β-Chains of the Haemoglobins of Nil Crocodile (Crocodylus niloticus) and Mississippi Crocodile (Alligator mississippiensis)
Authors: Schäfer W. , Braunitzer G. , Stangl A. 
Published: August 2018

Abstract
To elucidate the molecular mechanism of the direct allosteric exchange of oxygen and hydrogen carbonate in the hemoglobins of crocodiles, the N-terminal sequence of the β-chains of the crocodiles of the Nile (Crocodylus niloticus) and of the Mississippi (Alligator mississippiensis) was studied. The N-terminal end of the peptide is blocked. By mass spectrometry the N-terminal sequences of both species were found to be N-acetyl-alanyl-seryl-phenyl-alanine. These data explain the absence of hemoglobin-phojphate interaction, the data are in good agreement with the stereochemistry postulated for allosteric exchange of oxygen and hydrogen carbonate in crocodilian hemo­ globins.