bluuebunny/crossref_metadata_2025_split huggingface dataset:
Histochemical Demonstration of an ATP-Dependent Ca2+-Pump in Bullfrog Myocardial Cells
Authors: Meyer R. , Stockem W. , Schmitz M. , Haas H. G. 
Published: August 2018

Abstract
In the present investigation different finestructural and histochemical procedures were employed to demonstrate normal morphology and Ca2+-transport mechanism in bullfrog atrial myocardium. For normal morphology specimens were fixed in 1% OsO4, 2.5% glutaraldehyde or liquid propane at - 185 °C before they were prepared for conventional embedding and freeze-etching, respectively. Special interest was focussed on the caveolae system, which is composed of single, spherical membrane invaginations (diameter, 85 nm), randomly distributed at the entire cell periphery. The caveolae enlarge the cell surface by 24.5% and occupy 8.5% of the cellular volume. The caveolae membrane contains a few intramembraneous particles with a diameter of 8.4 nm comparable to the size of ATPases as found in other cells.
For histochemistry the specimens were first stabilized by treatment with 50% glycerol, 0.025% glutaraldehyde or 0.15% formaldehyde and then incubated in a medium containing 4 mᴍ CaCl2, 4 mᴍ EGTA, 5 mᴍ MgCl2, 5 mᴍ K2C2O4, 5 mᴍ ATP and 20 mᴍ histidine at pH 7.0. This incubation always succeeded in the formation of electron-dense deposits with elliptical shape, measuring 100 -200 nm in length and 10 -30 nm in diameter. According to X-ray spectra they deliver a characteristic calcium-peak and can be found within two different cellular compartments: in small invaginations of the sarcolemma, i. e. the caveolae-system, and in the intrafibrillar sarcoplasmic reticulum.
The elliptical deposits can be clearly distinguished from round electron-dense granules measuring 16 nm in diameter, which are located within randomly distributed small vesicles and composed of potassium and phosphate. Contrary to the elliptical deposits the round granules are also present in controls and seem to be identical with the so-called atrial granules.
In comparison to observations obtained with the same method in other muscular systems and derived from various control experiments the results of this study favour the existence of an ATP-dependent Ca2+-pumping mechanism in frog atrial muscle bound to both, the sarcoplasmic reticulum and the caveolae system.
Notizen: Effect of Penicillins on the Level of Inorganic Pyrophosphatase in Escherichia coli K 12
Authors: Kukko E. I. , Heinonen J. K. 
Published: August 2018

Abstract
The relative rate of DNA synthesis increases over control level and the synthesis of inorganic pyrophospha­tase is stimulated when cells of E. coli are cultured in the presence of penicillins which inhibit cell division and cause filamentation of the cells. In contrast to that in temperature sensitive cell division mutants filamentation at 42 °C does not change the DNA/cell mass ratio and the synthesis of inorganic pyrophosphatase is not stimulated. This suggests that the change in the synthesis of the enzyme is not correlated with the filamentation but is a consequence of the supernormal DNA/cell mass ratio that appears in the presence of penicillins.
Herbicides which Inhibit Electron Transport or Produce Chlorosis and Their Effect on Chloroplast Development in Radish Seedlings. III. Plastid Pigment and Quinone Composition
Authors: Grumbach K. H. 
Published: August 2018

Abstract
The effect of DCMU, bentazon, amitrole and SAN 6706 on the formation of chloroplast pigments and quinones was investigated using plants that were grown in total darkness or continuous white, red or far-red light.
All herbicides assayed affected the formation of chlorophylls, carotenoids and quinones but DCMU had only minor effects. Like for chlorophylls and carotenoids the formation of quinones was most suppressed in plants grown in the presence of the herbicide in continuous white or red light, but the effect on the formation of quinones was much lower as compared to the pigments. The observation that the biosynthesis of quinones is still maintained in SAN 6706 treated bleached plastids which are lacking chlorophylls and carotenoids indicates that quinones are synthesized at the plastitd envelope and stored in the osmiophilic plastoglobuli.
Amitrole and SAN 6706 induced a strong chlorosis. It was of particular interest that chlorosis was also induced by the photosystem II inhibitor bentazon. DCMU was not effective. The inhibitor concentration for 50% inhibition in the chlorophyll and carotenoid content was 5 × 10-6 ᴍ for SAN 6706,3 × 10-4 ᴍ for amitrole and 10-3 ᴍ for bentazon.
As already reported by others SAN 6706 treated plants accumulated phytoene in large amounts. The highest phytoene content was observed in plants that were grown in the dark. Amitrole treated plants accumulated lycopene. But in addition other carotenoid precursors like phytoene and phytofluene were also accumulated. In contrast to phytoene lycopene was only accumulated in plants that were grown in the light.
Particularly for SAN 6706 and amitrole the expression of the bleaching effect was depending on the light intensity and light quality that was used during plant growth. The herbicide effect ewas predominantly expressed at higher light intensities and after irradiation with red light. The observation that the induction of chlorosis is very sensitive to red light as compared to white or blue light is suggesting that phytochrome is involved in the development of the herbicide toxicity. It also supports that in SAN treated plants chlorophylls are photodecomposed directly by light because of the lack of photoprotecting carotenoids but mainly β-carotene in these plastids. Further support for this was given by the demonstration that SAN treated plants which were grown at very low light intensities turned green and were photosynthetically active.
The Anatomy of the Sarcoplasmic Reticulum in Vertebrate Skeletal Muscle: Its Implications for Excitation Contraction Coupling
Authors: Sommer Joachim R. 
Published: August 2018

Abstract
The sarcoplasmic reticulum in situ is an intricate tubular network that surrounds the contractile material in striated muscle cells. Its topographical relationship to other intracellular components, especially the myofibrils, is rather rigidly mainiained by a cytoskeleton which enmeshes Z line material and sarcoplasmic reticulum and, ultimately, is anchored at the plasmalemma. As a result, the two main components of the sarcoplasmic reticulum, the junctional SR and the free SR, retain their typical location in the A band region and in the I band region, respectively. The junc­tional SR, which is thought to be the site for calcium storage and release for contraction, is, thus, always well within one micron of the regulatory proteins associated with the actin filaments. The junctional SR, a synonym for terminal cisterna applying to both skeletal and cardiac muscle, is generally held to be involved in the translation of the action potential into calcium release, mainly because of the close topographic apposition between the junctional SR and the plasmalemma, especially in skeletal muscle. This attractive structure-function correlation is challenged by the observation that in bird cardiac muscle 80% of the junctional SR is spacially far removed from plas­malemma, the site of electrical activity. This anomalous topography is not in conflict with the notion that translation of the action potential into calcium release may be accomplished by a dif­fusible transmitter substance, e.g. calcium. Any hypothesis dealing with this problem must ac­ count for the anatomy of the bird heart.
Electromechanical Coupling II. The Effect of Perchlorate Upon Excitation-Contraction Coupling in Frog Skeletal Muscle Fibres
Authors: Gomolla Michael , Gottschalk Gernot , Lüttgau Hans-Christoph 
Published: August 2018

Abstract
In single skeletal muscle Fibres perchlorate causes a large shift of the potential dependence of contraction activation to more negative potentials without a corresponding alteration in the kinetics of the inactivation process.
Isolation and Identification of Lathycarpin, a New Pterocarpan Phytoalexin from Lathyrus sativus
Authors: Ingham John L. , Markham Kenneth R. 
Published: August 2018

Abstract
After treatment with the fungus Helminthosporium carbonum or aqueous copper sulphate, excised Lathyrus sativus leaflets produce pisatin and a second isoflavonoid phytoalexin (lathycarpin) identified as (+)-6aR; 11aR-2,3-dimethoxy-6a-hydroxy-8,9-methylenedioxypterocarpan.
New Papaveraceae Alkaloids Including an 7,8-Oxygenated Isoquinoline, the Postulated Precursor of the Cularine Alkaloids
Authors: Blaschke G. , Scriba G. 
Published: August 2018

Abstract
The first 7,8,3',4'-oxygenated benzylisoquinoline, the probable precursor of the cularine alkaloids, has been isolated together with 2 new cularines and 10 other alkaloids from Corydalis claviculata.
Epicuticular Waxes from Leaves and Stems of Jojoba (Simmondsia chinensis [Link] Schneider)
Authors: Gülz Paul-Gerhard , Eich Claudia 
Published: August 2018

Abstract
Epicuticular waxes were extracted with chloroform from air dried Jojoba leaves and stems. These cuticular waxes consisted of homologues of n-alkanes, branched alkanes, alkenes, wax esters, aldehydes, acetates, esters, free long chain fatty acids and alcohols. Both leaves and stems showed the same qualitative and quantitative composition with similar distribution patterns. Very long chain and in most cases saturated compounds are dominating. The composition of epicuticular waxes from Jojoba leaves and stems is quite different from that of Jojoba pericarp and seed coats and demonstrates an organ specific wax composition of different aerial parts of this plant.
3′-Hydroxylation of 4′-Methoxyisoflavones by Fusarium oxysporum f. lycopersici
Authors: Mackenbrock K. , Barz W. 
Published: August 2018

Abstract
3′-Hydroxylation of isoflavones by Fusarium oxysporum f. lycopersici mainly proceeds with 4′-methoxy-7-hydroxyderivatives; this reaction is used for quantitative conversion of 14C-labelled isoflavones.
Chemistry of Bacteriochlorophyll b: Identification of Some (Photo)Oxidation Products
Authors: Steiner R. , Cmiel E. , Scheer H. 
Published: August 2018

Abstract
Photoreactions of bacteriochlorophyll b have been studied. They all arise from reactions at the Δ8,81 double-bond. The Δ7,8-isomerisation product 3 is formed under anaerobic conditions. Irradiation in the presence of oxygen leads to three products arising from an autoxidation reaction involving singlet oxygen. The structures of two of them (4, 5) have been established from their methylpheophorbides 10 and 11 containing an 8-acetyl and 8-(meth)oxyethyl-substituent, respectively, in addition to the isomerized Δ7,8-double bond.
Electroimmunodiffusion — a Powerful Tool for Quantitative Determinations of Both Soluble and Membrane Bound Chloroplast ATPase, CF1
Authors: Roos Peter , Berzborn Richard J. 
Published: August 2018

1. Electroimmunodiffusion can be used for routine specific quantitative microdeterminations of photosynthetic ATP-synthase. The method has been worked out for samples of both the dissociated (CF1) and the membrane bound enzyme (CF0CF1).
2. Only a monospecific antiserum against CF1 , is required for relative determinations of CF1 in any fraction. If beyond this an absolute determination is intended of either the separated or the membrane bound ATPase, in addition a pure CF1 , is needed for calibration.
3. A varying CF1/chlorophyll ratio between 1/700 and 1/1200 has been found for thylakoids of spinach plants grown under various light intensities.
4. Since the amount of CF1 , was the limiting factor of photophosphorylation capacity in the electron transport system used (PMS), from simultaneous measurement of CF1 , content and photophosphorylation capacity a turn over time of the ATPsynthase of 4 ms /ATP /CF0CF1 could be recalculated.
Increased Binding of [14C]Ioxynil in Unicellular Green Algae under Anaerobiosis and by Addition of Other Phenolic Herbicides or Uncouplers
Authors: Neumann Wiltrud , Laasch Henrik , Urbach Wolfgang 
Published: August 2018

Binding of the phenol-type herbicide ioxynil in intact algal cells is strongly increased under anaerobic conditions. This increase is most pronounced at low concentrations of bound ioxynil (< 3 nmol/mg chlorophyll). The affinity of binding sites is improved, rather than new sites are created.
Other phenol-type herbicijdes, as well as uncouplers like carbonylcyanidechlorophenylhydra- zone. also significantly increase ioxynil binding in algae. Binding of DCMU-type herbicides, however, was not affected.
These results demonstrate high variability of ioxynil binding in algal cells and are discussed in respect of low affinity binding.
Hydroxycinnamoyl Esters of Malic Acid in Small Radish (Raphanus sativus L. var. sativus)
Authors: Brandi Wilfried , Herrmann Karl , Grotjahn Lutz 
Published: August 2018

Abstract
The esters of p-coumaric, ferulic and caffeic acid with malic acid were isolated from leaves, the ester of sinapic acid with malic acid from cotyledons of Raphanus sativus plants via preparative HPLC. The esters were identified by hydrolyses and following capillary GC , by H-NMR and FAB-MS. Their concentrations in leaves and tubers were determined by gradient HPLC on reversed phase material.
Rabbit Antipeptide Antibodies against Restricted Domains of the Histocompatibility Complex
Authors: Chersi Alberto , Houghten Richard A. 
Published: August 2018

The work reported here concerns the specificty of four antibodies elicited by synthetic peptides corresponding to three domains of the HLA-B7 glycoprotein, and one of the β2 microglobulin. One of the four peptides had been previously investigated, but the data obtained by its elicited antibodies were uncomplete.
Of the three HLA-B7 peptides assayed, one was unable to raise an immune response. The other two produced antibodies in good titer that reacted with the antigen peptide, but were unable to recognize antigenic determinants when tested on membrane glycoproteins solubilized from human lymphoblastoid cells. In contract, the antibody elicited by the only fragment from the β2microglobulin recognized the native β2microglobulin molecule as well as HLA/β2m com­plexes, and reacted with intact human cells, as determined by ELISA and by FACS analysis. This peptide, which contains one of the most hydrophylic fragment of the whole molecule, is likely an important antigenic site, since it is also recognized by traditional antisera raised against native β2 microglobulin.
Pistillarin, ein charakteristischer Inhaltsstoff der Herkuleskeule (Clavariadelphus pistillaris) und einiger Ramaria-Arten (Basidiomycetes) / Pistillarin, a Characteristic Metabolite of Clavariadelphus pistillaris and Several Ramaria Species (Basidiomycetes)
Authors: Steglich Wolfgang , Steffan Bert , Stroech Klaus , Wolf Maria 
Published: August 2018

Abstract
From Clavariadelphus pistillaris and several Ramaria species a bitter substance, pistillarin, has been isolated which is responsible for the green colour reaction of the fruit-bodies with FeCl3. Its structure has been determined as N1,N8-bis(3,4-dihydroxybenzoyl)spermidine (1).
Nickel-Dependent Uptake-Hydrogenase Activity in the Blue-Green Alga Anabaena variabilis
Authors: Almon Helmar , Böger Peter 
Published: August 2018

Abtract
Uptake-hydrogenase activity in the blue-green alga (cyanobacterium) Anabaena variabilis is dependent on the presence of nickel. Nickel depletion leads to an enhancement of net lightinduced hydrogen evolution, which is catalyzed by nitrogenase. Addition of nickel chloride to the culture reverses this effect by stimulating hydrogenase activity. Methylviologen/dithionitedriven hydrogen formation of permeabilized cells is decreased by nickel depletion.
Cell Cycle Kinetics and Metabolism of Ehrlich Ascites Tumor Cells in the Presence of Chloramphenicol as Inhibitor of Mitochondrial Protein Synthesis
Authors: Kroll Werner , Schneider Fr. 
Published: August 2018

In the presence of 150(μ/ml of chloramphenicol, viability (dye exclusion test) of Ehrlich ascites tumor cells is not severely affected within 48 h; however the number of dead cells increases above this concentration; more than 10 mg/ml render all of the cells dye-positive within a culture period of 24 h. With the highest concentration tested (25 mg/ml) cells begin to lose viability 8 h after beginning of treatment.
In the first passage in the presence of the antibiotic, proliferation of the cells is reduced by about 50%; in the second passage cell growth was about 65% that of controls. As is shown by flow cytometric analysis and BrdU-H33258 technique of flow cytometry, the reduction of proliferation in the second passage is caused by retardation of cell cycle progression of about 8 h; in the third passage the cell cycle is delayed by further 8 h as compared to controls. On recultivation in the third passage in the absence of the inhibitor an increase of cell number of about 75% of controls was observed.
Lactate production and glucose uptake of the cells were stimulated by the inhibitor by about 20%; oxygen consumption was 60% that of controls after 24 h; however the ATP/ADP ratio of chloramphenicol treated cells was in the range of controls.
Over a time period of 24 h the incorporation of [2-14C]thymidine is reduced to 34 ± 3%, incorporation of [2-14C]uridine was 88 ± 4% that of controls, incorporation of [U-14C]lysine was not significantly affected by 150 μg/ml of chloramphenicol; the same was found for the uptake of [2-14C]-α-aminoisobutyric acid.
Electron micrographs of chloramphenicol treated cells reveal a high amplitude of swelling of all mitochondria with a translucent appearance of the inner compartment. The mitochondrial membranes remain largely intact but the number of cristae is drastically reduced.
Electron Microscopic Evidence for the Transmembrane Displa cement of Calcium ATPase
Authors: Scales Donald J. , Highsmith Stefan R. 
Published: August 2018

Abstract
Incubation of the Ca2+-ATPase in vanadate solutions leads to the formation of two-dimensional arrays in the sarcoplasmic reticulum membrane. Electron micrographic freeze fracture replicas show depressions on the inner leaflet for the first time. This indicates that the ATPase has moved perpendicular to the plane of the membrane. Our results also suggest that aggregation of the Ca2+-ATPase into the two-dimensional arrays occurs before they move into the membrane. These phenomena were observed as soon as 15 minutes after vanadate was added. The effects of vanadate appear to be completely reversible. When SR was incubated in the vanadate solutions and was then diluted into a buffer containing Ca2+ and ATP, the ATPase activity was normal for up to several hours of incubation and only somewhat reduced after 3 days.
Pressure Induced Shifts in Spectral Properties of Pigment-Protein Complexes and Photosynthetic Organisms
Authors: Brody Seymour Steven , Heremans Karel 
Published: August 2018

Abstract
Application of elevated pressure (up to 1200 bars) results in a bathochromic shift of the absorption bands of photosynthetic pigments. The photosynthetic systems studied include: photosystem I particles, chloroplasts, acetone extracts of chloroplasts, AUT particles and light harvesting particles of Rh. sphaeroides, light harvesting particles of R26. Similar spectral changes are observed in all systems. The spectral shifts appear to be associated with pressure-induced changes in the local electric fields of the pigments, rather than changes in the index of refraction of the solvent.
Oxygen Supply of Roots by Gas Transport in Alder-Trees
Authors: Große Wolfgang , Schröder Peter 
Published: August 2018

Abstract
It is generally accepted that oxygen diffuses according to the gradient of its partial pressure from the surface of the plants into the heterotrophic tissues through the inter­cellular spaces. The present experiments show evidence of an additional manifold higher oxygen supply due to a gas transport in leaved as well as leafless trees of Alnus glutinosa (L.) Gaertner. This gas transport is directed from the stems to the roots. It is driven by a thermo-osmotic pressurisation within the air space system of the stems, resulting from temperature gradients up to 3.6 K between the stem and the ambient air following the absorption of light energy by the brownish pigments of the bark. This gas phase phenomena appears to enable the alder-trees to survive and grow in wet soil resulting from a high water table or in waterlogged soil.
Identification and Field Evaluation of a Sex Pheromone of the European Pine Moth
Authors: Priesner E. , Bogenschütz H. , Albert R. , Reed D. W. , Chisholm M. D. 
Published: August 2018

Abstract
The principal component of the female sex pheromone of the European pine moth Dendrolimus pini L. (Lasiocampidae) was identified as (Z ,E)-5 ,7-dodecadienal by capillary gas chromatography, mass spectrometry, single receptor analyses, and field trapping tests. Traps initially baited with 1000 μg of (Z,E)-5,7-dodecadienal (>99%ZE) effectively monitored low D. pini populations over 6 weeks without rebaiting. Captures disappeared upon addition of ≧1% of either (E,Z)-5,7-dodecadienal or (Z,E)-5,7-dodecadienyl acetate, the key stimulants for additional receptor cell types located in male antennal hair sensilla.
Conversion of Dihydroflavonols to Flavonols with Enzyme Extracts from Flower Buds of Matthiola incana R. Br.
Authors: Spribille R. , Forkmann G. 
Published: August 2018

Abstract
Soluble enzyme preparations from flower buds of Matthiola incana catalysed the conversion of dihydrokaempferol to kaempferol and of dihydroquercetin to quercetin. The reaction required 2-oxoglutarate, ascorbate and Fe2+ as cofactors and had a pH-optimum at about 7.0. Highest enzyme activity was already present in the youngest buds followed by a rapid decline during bud and flower development. Furthermore, a substantial correlation was observed between the enzyme activity for flavonol formation and the flavonol content of the buds and flowers.
Studies on the Possible Mechanism of Inactivation of Phenylalanine Hydroxylase by Destructive Oxygen Species
Authors: Fink Rita M. , Elstner Erich F. 
Published: August 2018

Abstract
The enzymic hydroxylation of phenylalanine by phenylalanine hydroxylase (E.C. 1.14.16.1.) in vitro is dependent on the presence of hydrogen peroxide removing processes.
The loss of phenylalanine hydroxylase activity can be prevented to the same extent by catalase as well as the presence of optimized amounts of both peroxidase and superoxide dismutase.
Peroxidase alone exhibited only two third of the maximal protective effect of catalase whereas superoxide dismutase alone was not able to exert any protective influence on phenylalanine hydroxylase. These findings suggest that the termination of phenylalanine hydroxylation in the absence of hydrogen peroxide removing reactions is probably due to destructive oxygen species generated at the active site iron of phenylalanine hydroxylase in the presence of H2O2 and the tetrahydropterin cofactor.
Distribution of the H1 Histone Subfractions in Syrian Hamster Chromatin Fractions
Authors: Modrzejewska Hanna , Gałązka Grażyna , Szemraj Janusz , Panusz Henryk 
Published: August 2018

Abstract
Chromatin from two Syrian hamster tissues: the Kirkman-Robbins hepatoma and the liver, has been separated into soluble (S) and insoluble (P) fractions. Both fractions contain the complete set of five main histones but differ in respect of H1 subfractions. The hepatoma chromatin is known to contain an unusual H1 subfraction, H1 slow [12, 13], probably identical with a similar subfration present in hamster testes. The content of H1 slow in total H1 histone has been estimated for total, S and P chromatin from hamster hepatoma. The values 20.9 ± 7.2, 13.8 ± 1.8 and 26.8 ± 4.2%, respectively, were obtained.