bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Subcellular Distribution of Calcium in the Visual Cells of Crayfish, Observed with the Combined Oxalate-Pyroantimonate Technique, Depends on Extracellular Calcium
Authors: Jarminowski Hans 
Published: August 2018

1. With the combined oxalate-pyroantimonate method we determined the subcellular distribution of calcium in the photoreceptor cells of the crayfish Orconectes limosus.
2. The calcium antimonate deposits were identified with the electron microscope. Energydispersion X -ray analysis verified that the electron dense deposits contained calcium and antimony.
3. Calcium antimonate deposits were found in the submicrovillar cisternae, mitochondria, multivesicular bodies, and pigment granules, as well as in the cytoplasm .
4. The calcium deposits in the cytoplasm of the retinula cell and in the pigment granules were reduced after incubation of the retinae in a solution with a lowered calcium concentration and even more after we permeabilized the plasma membrane with the saponin β-escin.
5. We suppose that the calcium -storing pigment granules participate in the regulation of the cytosolic calcium concentration of the crayfish photoreceptor cells.
Notes: External Flavonoids of Three Species of Viguiera, Section Hypargyrea (Asteraceae)
Authors: Wollenweber Eckhard , Dörr Marion , Roitman James N. , Schilling Edward 
Published: August 2018

Abstract
The flavonoid aglycones excreted by aerial parts of three Viguiera species have been analyzed. One of them is a rare natural product. So far unpublished NMR data are reported for three flavones. Each species of V. sec­tion Hypargyrea exhibits a distinctive flavonoid profile based on different patterns of methoxylation, but the taxonomic section as a whole is not characaterized by any distinctive characters of its flavonoid chemistry.
Xanthine Oxidase and Xanthine Dehydrogenase from an Estivating Land Snail
Authors: Hermes-Lima Marcelo , Storey Kenneth B. 
Published: August 2018

Abstract
During arousal from estivation in land snails. Otala lactea, active metabolic functions are restored within minutes and oxygen consumption increases dramatically. During the transition from the hypoxic conditions of estivation to normoxia it is possible that xanthine oxidase (XO ) in hepatopancreas contributes to the observed lipid peroxidation. Using a fluorometric assay that is based on the oxidation of pterin, the activities and some properties of XO and XO+XDH (sum of XO and xanthine dehydrogenase activities) were measured in hepatopancreas extracts. Km values for pterin for XO and X O +XDH were 9 and 6 μm, respectively, and the Km of XDH for methylene blue was 5 μm . Both XO +XDH and XO activities were inhibited by allopurinol (I50 = 2 μm ) , pre-incubation at 40 °C, and by 5 min H2O2 pre-exposure. Inclusion of azide in the reaction promoted a rise of approximately 70-fold in the inactivation power of H2O2 due to inhibition of high endogenous catalase activity. The /so for H2O2 of XO +XDH and XO activities in the presence of azide was 0.04 and 0.11 mM , respectively. Unlike the situation for mammalian XO. a previous reduction of O. lactea XO (by pterin) was not necessary to make the enzyme susceptible to H2O2 effects. Interestingly, methylene blue partially prevented both heat- and H20 2-induced inactivation of XO +XDH activity. These data indicate that the formation of an enzyme-methylene blue complex induces protection against heat and oxidative damage at the FAD-active site. Both XO and XO +XDH activities were significantly higher in snails after 35 days of estivation compared with active snails 24 h after arousal from dormancy. The ratio of XO /(XO +XDH) activities was also slightly increased in estivating O. lactea (from 0.07 to 0.09; P < 0.025). XO activity was 0.03 nmol · min-1 · mg protein-1 in estivating snails. Compared with hepatopancreas catalase, XO activity is probably too low to contribute significantly to the net generation of oxyradicals, and hence to peroxidative damage. Rather, the low potential of XO to induce oxidative stress may constitute an adaptive advantage for O. lactea during arousal periods
Action of Hypochlorous Acid on Polymeric Components of Cartilage. Use of 13C NMR Spectroscopy
Authors: Schiller Jürgen , Arnhold Jürgen , Arnold Klaus 
Published: August 2018

Abstract
Hypochlorous Acid, Cartilage, Chondroitinsulphate, Carbon NM R Spectroscopy It is a well known fact that neutrophil-derived hypochlorous acid plays an important role in cartilage destruction during rheumatoid arthritis. It has been shown by 1H NMR spectro­scopy in a previous paper (Schiller et al. (1994), Biol. Chem. Hoppe-Seyler 375, 167-172) that sodium hypochlorite affects primarily the N-acetyl side chains of polymeric carbohydrates of cartilage like chondroitinsulphate and hyaluronic acid. An instable intermediate, likely to be a chloramine, is involved in these processes. The present paper deals with the application of carbon NMR spectroscopy for the study of these degradation processes, because carbon NMR gives the opportunity to detect changes on the single sugar ring carbons. Although it was not possible to prove the involvement of an intermediate, because of its fast hydrolysis, we were able to show that the reaction between sodium hypochlorite and N-acetylglucos-amine affects mainly the side chain, accompanied by of a large excess of sodium hypochlorite leads to under the formation of formiate.
Isolation and Characterization of an Angular- Type Dihydropyranocoumaringlycoside from the Fruits of Ammi visnaga (L.) LAM. (Apiaceae)
Authors: Sonnenberg H. , Kaloga M. , Eisenbach N. , Frömming K.-K. 
Published: August 2018

Abstract
An angular-type dihydropyranocoumaringlucoside, namely, cis-Khellactone-3′-β-D-glucopyranoside (1) was isolated from the fruits of Ammi visnaga (L.) LAM. (Apiaceae). The structure was established on the basis of acid hydrolysis and spectral data
Specifities of Rabbit Antisera to Multiple Antigen (MAP) Peptides
Authors: Chersi Alberto , Modugno Francesca di , Falasca Giuliana 
Published: August 2018

Abstract
Two multiple antigen peptides consisting of 6 and 7 amino acid residues, respectively, plus a 12-residue fragment, used as a control, all linked to a polylysine core, were used as immunogens in rabbits in order to obtain an immune response. Rabbit antisera against such polymers were then tested in ELISA against a panel of antigens in order to analyze the specificites of the resulting antibodies. The responses were different for all three immunogens, being partially or totally directed, for two of the three compounds, including the 12-residue control MAP peptide, against the polylysyl core, which is considered as non immunogenic. The third MAP polymer was practically unable to elicit an immune response
Self-Organized Criticality and Dynamic Instability of Microtubule Growth
Authors: Babinec Peter , Babincová Melánia 
Published: August 2018

Abstract
We have shown that the distribution of lengths of site nucleated microtubules obey an algebraic power law relationship D(s) = As-τ, where D(s) is relative number of microtubules with length 5, A and τ are constants. This relationship indicates the possibility of a self-organized criticality in the dynamic instability of microtubule growth
C-Methyl Flavones from the Leaf Wax of Leptospermum laevigatum (Myrtaceae)
Authors: Wollenweber Eckhard , Roitman James N. 
Published: August 2018

Abstract
Flavonoid aglycones were detected as minor constituents of the leaf wax of the Myrtaceae Leptosperm um laevigatum. They belong to the rarely encountered C-methyl flavonoids. One of them is a new natural product, 5-hydroxy-3,7,3′,4′-tetramethoxy-6-C-methyl flavone.
A Minimum Essential Structure of LN-3 Elicitor Activity in Bean Cotyledons
Authors: Tai Akihiro , Ohsaw Eri , Kawazu Kazuyoshi , Kobayashi Akio 
Published: August 2018

Abstract
A great deal of an elicitor-active oligosaccharide (1.47 g) was obtained from 40 g of poly­ saccharide laminaran with the guidance of elicitor activity in the bean cotyledon assay. Physicochemical means suggested that the oligosaccharide was a β-1,3-and β-1,6-linked triglucoside. This was a partial structure of LN-3, having elicitor activity to alfalfa and bean. The triglucoside exhibited a specific elicitor activity to bean, not to alfalfa and pea. The highly digested hydrolysate containing monom er and dimers as major components did not show elicitor activity in the bean cotyledon assay. The structural feature was essential for elicitation of phytoalexin accumulation in bean cotyledons. These results suggested that this triglucoside had a specific elicitor activity and a minimum elicitor-active entity to bean cotyledons.
Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II
Authors: Gruszecki W. I. , Strzałk K. , Bader K.P. , Radunz A. , Schmid G.H. 
Published: August 2018

Abstract
In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosynthetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ferent light quality and thylakoids having various levels of xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means of mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and of light-induced oxygen uptake indicate that the de-epoxidation of violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin.
The Light-Stimulated Cytosolic Calcium Transient in Limulus Ventral Nerve Photoreceptors: Two Components in the Rising Phase
Authors: Stommel Georg , Dorlöchter Marlies , Rüsing G abriele , Stieve Hennig 
Published: August 2018

Abstract
1. Light-evoked electrical responses were measured in Limulus ventral nerve photoreceptors simultaneously with changes in the cytosolic free calcium concentration, by means of arsenazo III.
2. It has been shown here for the first time that the rise of the arsenazo signal consists of two phases. Only the slow phase in the rise of the signal depends on the membrane voltage. The reversal potential of the amplitude of this slow rising phase was about +196 mV. After removal of external calcium the reversal potential was about +20 mV.
3. When Na+ in the superfusate was replaced by Li+, the amplitude of the fast rising phase was reduced on the average to 50%, while the slow rising phase was not affected.
4. We conclude that the fast rising phase is caused by release of calcium from internal stores while the slow increase in [Ca2+]i is due to influx across the plasma membrane, possibly through light-activated ion channels.
Bi-and Triflavonoids of Representative Moss Species from Six Different Families
Authors: Zinsmeister Hans Dietmar , Weyand Judith , Voigt Ariane , Seeger Tassilo , Geiger Hans 
Published: August 2018

Abstract
The identity of the bi- and triflavonoids of six moss species from six different families has been proved by NMR. The individual flavonoids are: 3′, 3‴-binaringenin, 5′, 3‴-dihydroxy-amentoflavone, 5′, 3‴-dihydroxyrobustaflavone, campylopusaurone, aulacomniumtriluteolin, philonotisflavone, dicranolomin, and 2, 3-dihydrodicranolomin.
Temperature Dependence of the O2-Oscillation Pattern in the Filamentous Cyanobacterium Oscillatoria chalybea and in Chlorella kessleri
Authors: Burda K , He P , Bader K. P , Schmid G. H 
Published: August 2018

Abstract
Five characteristic discontinuities of the pattern of oxygen evolution have been detected for the filamentous cyanobacterium Oscillatoria chalybea in the temperature range of 0°C to 30°C. The temperatures at which these discontinuities occur are: ≈ 5°C, ≈ 11°C, ≈ 15°C, ≈ 21°C and ≈ 25°C. The calculated initial 5-S state distribution, the miss parameter and the fraction of the fast transition S3 → S0+ O2 are affected. The discontinuities are observed at the same transition temperature also for Chlorella kessleri hence are not specific for the cyanobacterium. Based on these studies it is concluded that the not vanishing oxygen signal under the first flash of a flash train in Oscillatoria cannot have its origin in interactions between oxygen-evolving complexes. A decrease of temperature should slow down the expected charge exchanges, improve the oscillations, thus reduce or lower the first two oxygen amplitudes of the oscillatoria pattern. Lowering of the temperautres improves the oscillations but does not lower the first O2 signal of the pattern.
Human Neutrophil Chemotaxis in Response to Diepoxides of Linolenic Acid
Authors: Scheick C , Spiteller G , Fröhlich W 
Published: August 2018

Abstract
Diepoxides of linolenic acid were found to be chemoattractants. The concentration that produces 50% of maximal chemotaxis was 4.5 10-7 mol/l for human neutrophils when investigated in a chemotaxis test based on the method of spectrophotometric determination of myeloperoxidase activity with buffers containing bovine serum albumin. Leukotriene B4 was used as positive control. The concentration of leukotriene B4 that produces 50% of maximal chemotaxis was 1.8 nmol/l. No chemotactic activity was observed when monoepoxides of linoleic or linolenic acid, diepoxides of linoleic acid or triepoxides of linolenic acid were used. Mono-, di-and triepoxides of polyunsaturated fatty acids were synthesized with meta-chloroperbenzoic acid, separated by TLC and HPLC and identified by GC/MS.
Crystallization of Intact and Subunit L-Deficient Monomers from Synechocystis PCC 6803 Photosystem I
Authors: Jekow Petra , Schubert Wolf-Dieter , Fromme Petra , Kruip Jochen , Chitnis Parag R. , Rögner Matthias , Saenger Wolfram 
Published: August 2018

Abstract
Photosystem I monomers from wildtype cells of Synechocystis PCC 6803 and from a mu­ tant deficient in the psaL gene were crystallized. PsaL encodes for the hydrophobic subunit L, which has been proposed to constitute the trimerization domain in the PS I trimer. The absence of subunit L facilitated crystallization of the PS I monomer. The unit cell dimensions and the space group for the crystals from this preparation could be determined to be a = b = 132 Å , c -525 Å, α = β = 90°, y = 120°, the space group is P61 or P65. The results show the potential of using specifically designed deletion mutants of an integral membrane protein for the systematic improvement of crystal structure data.
Photosynthesis and Transpiration in Damaged and Undamaged Spruce Trees
Authors: Wild Aloysius , Sabel Peter , Wild-Peters Lucia , Schmieden Ursula 
Published: August 2018

Abstract
The investigations presented here focus on the CO2/H2O gas exchange in damaged and undamaged spruce trees while using open-air measurements as well as measurements under defined conditions in the laboratory. The studies were performed at two different sites in the Hunsrück and the Westerwald mountains. In the laboratory the CO2/H2O gas exchange was measured on detached branches under controlled conditions in the course of two years. CO2 saturation curves were also generated. In addition CO2 compensation points were deter­ mined employing a closed system. In the natural habitat diurnal course measurements of photosynthesis and transpiration as well as light-saturation curves for photosynthesis were performed. In parallel with the photosynthesis and transpiration measurements, measurements of the water potential were taken at both locations. The photosynthetic capacity and transpiration rate show a typical annual course with pronounced maxima in spring and late summer and minima in summer and winter. The needles of the damaged trees exhibit higher transpiration rates and a distinct reduction in photosyn­ thesis than the needles of the undamaged trees during two seasons. The diurnal course measurements of net photosynthesis and transpiration show a maximum in photosynthesis and transpiration in the afternoon in May and September, but a characteristic midday depression in July. Photosynthesis was markedly lower and transpiration higher in the needles of the damaged trees. The damaged trees show a lower increase in the light and CO2 saturation curves and higher CO2 compensation points as compared to the undamaged trees. The water potential reaches much lower values during the course of the day in needles of the dam­ aged trees. The reduction of the photosynthetic rate on one hand and the increase in transpiration on the other hand result in an extreme lowering of the water use efficiency in photosynthesis. The damage to the thylakoid membranes and to the guard cells obviously results in a pro­ found disturbance of the physiological homeostasis of the needles and could thus lead to premature needle loss.
Interaction of Penicillin G with the Human Erythrocyte Membrane and Models
Authors: Suwalsky M. , Villena F. , Aguilar F. , Sotomayor C. P. 
Published: August 2018

Abstract
Penicillin G (PEN) is a widely used antibiotic whose mechanism of action is related to the interference with the synthesis of bacteria cell wall. In order to evaluate its perturbing effect upon human cell membranes PEN was made to interact with human erythrocytes, isolated resealed human erythrocyte membranes and molecular models. The latter were multibilayers of the phospholipids dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidyl-ethanolamine (DMPE) as well as DMPC large unilamellar vesicles. These studies were per­ formed by scanning electron microscopy, fluorescence spectroscopy and X-ray diffraction methods. The observed results coincide in that PEN did not exert any significant effect upon the structures of the red cell membrane neither on its molecular models. This is in agreement with its reported lack of major toxicity and hem atological reactions.
Optimization of Fast-Fluorescence in situ Hybridization with Repetitive α-Satellite Probes
Authors: Durm Markus , Haar Frank-Martin , Hausmann Michael , Ludwig Horst , Cremer Christoph 
Published: August 2018

Abstract
A rapid FISH (fluorescence in situ hybridization) technique (Fast-FISH) for quantitative microscopy has been recently introduced. For highly repetitive D N A probes the hybridization (renaturation) time and the number of necessary washing steps were reduced considerably by omitting formamide or equivalent denaturing chemical agents. Due to low stringency conditions major and minor binding sites of the probes used showed visible FISH signals well suited for quantitative image-microscopy. The discrimination of minor and major binding sites was possible by automated image-processing. Here, a further, quantitative optimization of the Fast-FISH technique is described that allows to clearly discriminate major and minor binding sites of a-satellite probes by an easy image classification parameter. With respect to the optimization it was necessary to verify two sensitive parameters (hybridization time and temperature) of the given rapid FISH protocol. A s examples the systematic optimization for the two probes D 12 Z 2 (major binding site on the centromere of chromosome 12) and D 8 Z 2 (major binding site on the centromere of chromosom e 8) are shown. The optimal hybridiza­tion conditions concerning rapidness and quality of chromosome morphology were obtained using a hybridization temperature of 70 °C and a hybridization time of 60 min. For these conditions major and minor binding sites were clearly discriminated by the intensity maxi­ mum Smax of the corresponding FISH-spots.
Catecholate Siderophores from Chryseomonas luteola
Authors: Adolphs M. , Taraz K. , Budzikiewicz H. 
Published: August 2018

Abstract
Two catecholate siderophores (chrysobactin and chryseomonin) were isolated from an iron-deficient culture medium of Chryseomonas luteola. Their structures were elucidated by chemical degradation studies and spectroscopic methods, especially 2D-NMR techniques, and confirmed by synthesis. Chryseomonin constitutes a novel type of catecholate siderophore.
Does the B820 Subcomplex of the B880 Complex Retain Carotenoids?
Authors: Moskalenko Andrey , Toropygina Olga , Kuznetsova Nina 
Published: August 2018

Abstract
A study is reported on the modification of the B880-RC assembly of Chromatium minutissimum during octyl-β-D -glucopyranoside/dodecyl-β-D -maltoside/Deriphat polyacrylamide gel electrophoresis followed by electroelution with dodecyl-β-D-maltoside and high performance liquid chromatography with octyl-β-D-glucopyranoside according to the method developed by Kerfeld et al. (Biochim. Biophys. Acta 1185, 193-202 [1994a]) for isolation of the B820 subcomplexes of Chromatium purpuratum. The B880-RC assembly of Chromatium minutissimum isolated by electrophoresis was contaminated by the B 800-850 complex. It was further separated into four components, three of which were in agreement with the cited work: (i) colorless contaminations, (ii) the B880-RC assembly, (iii) the B 800-850 complex. In contrast with Kerfeld et al. (1994a), the fourth band was a band of free pigments (Bchl or Bchl-t-carotenoids) which had the same molecular mass as the B820 subcomplex of Chromatium purpuratum.
For comparison, the B880-RC enriched fraction of Rhodospirillum rubrum modified by lyophilization in the presence of octyl-β-D-glucopyranoside with or w ithout carotenoids was separated by high performance liquid chromatography with octyl-β-D-glucopyranoside. The apparent molecular mass of the B820 subcomplex was 30 kD a for the sample without carotenoids and 245 kD a for that with carotenoids.
The common principles of organization of the B880 complex, the interaction of the B 800- 850 complex with the B880-RC assembly, the participation of carotenoids in the stabilization of the B880 complex structure and the ability of different isolation steps to modify the structure of the B880 complex are discussed. It was concluded that there are other explanations for the presence of carotenoids in the B820 subcomplex. Hence, the question of whether the B820 subcomplex retains carotenoids remains open.
On the Determination of the 5-State Distribution in the Kok Model
Authors: Burda K. , Schmid G. H. 
Published: August 2018

Abstract
We use the Markow chain theory to analyze the oscillation pattern of oxygen evolution during water oxidation in photosystem II under short saturating light flashes. We propose a method based on the standard least square deviation (test X2) to determine the number of 5-states in the Kok model. As pointed out by Burda et al. (1995) this information is amongst others important for the interpretation of the role of calcium for oxygen evolution. A specific mathematical representation for a situation when the S4 state is longer living than generally assumed is introduced which requires an explicit extension of the Kok model to five states. The higher stability is modelled by introducing additional decay channels, e.g. a nonvanishing probability for the transition of S3 to the S0 state and a further transition probability for the transition from S3 to S4. Our analysis is extended to the case of damped oscillations of oxygen evolution caused, for example, by the lack of electron acceptor or the short life time of photosystem II particles.
The Exocrinology of the Queen Bumble Bee Bombus terrestris (Hymenoptera: Apidae, Bombini)
Authors: Hefetz Abraham , Taghizadehr Timo , Francke Wittko 
Published: August 2018

Abstract
Chemical analyses are presented of prominent exocrine glands of queen Bombus terrestris including mandibular, labial and hypopharyngeal glands in the head, Dufour’s gland and tarsal glands. A plethora of about 500 substances were identified belonging to various ali­phatic compounds including hydrocarbons, various classes of esters, alcohols, methyl ketones and fatty acids. A group of chiral hydroxy acids and their butanoic acid esters are reported for the first time in bees.