bluuebunny/crossref_metadata_2025_split huggingface dataset:
Different Expression of Esterase Variants in Rat Hepatic and Hepatom a-Derived Cell Lines Detected by Electrophoresis
Authors: Afify Adel S. , Yamazaki Yoshimitsu , Kageyama Yu-ichi , Yusa Shiro , Ogawa Yoshikatsu , Okada Tomoko , Okuno Hiroaki 
Published: August 2018

Abstract
Esterases in nine rat hepatic and hepatoma-derived cell lines and normal rat liver homogenate were detected by polyacrylamide gel electrophoresis coupled with active staining with a-naphthyl acetate or butyrate as a substrate. The esterase band patterns of the non-cancerous and oncogene-transformed cell lines were alike, but different from those of hepatoma cell lines and normal rat liver homogenate. The former groups of cells might have completely lost the characteristics of rat liver parenchymal cells, or else they might have their origin at cells other than liver parenchyma. The esterase patterns of the hepatoma cell lines (e.g., McA-RH7777) and the normal rat liver highly resembled with each other, exemplifying the slight biochemical deviation of cancer from normal cells. However, two-dimensional electrophoretogram for the McA-RH7777 cell line showed a prominent esterase spot {p/ 6.0-Mr 110 kDa) that was lacking in the normal liver. This result indicates that there is invariably some change in esterase expression between the cancer cells and the normal liver cells
Cytochemical Localization of Guanylate and Adenylate Cyclase in Photoreceptor Cells of the Fly
Authors: Schraermeyer Ulrich , Stieve Hennig , Rack Michael 
Published: August 2018

Abstract
In photoreceptor cells of invertebrates light triggers an enzyme cascade in which the phos-phoinositide pathway is crucially involved. Likewise, there is growing evidence of an impor­ tant role of cyclic nucleotides, too. To localize these enzymes able to catalyze the formation of cGM P and cAMP, the spatial distribution of guanylate cyclase (EC 4.6.1.2) and adenylate cyclase (EC 4.6.1.1) was determined in photoreceptor cells of the fly. In photoreceptor cells of the blowfly (Calliphora erythrocephala), the electron dense reaction product of guanylate cyclase was found within the phototransducing region, the rhabdomeral microvilli and in the mitochondria. Staining was also observed throughout the cytoplasm of the microvilli. With the same cytochemical method, reaction product for adenylate cyclase was found on the tips of the photosensory membrane, and not in the cytoplasm of the rhabdomeral microvilli. The results presented here further argue for an important role of one or possibly two cyclic nucleotides in the photoreceptor cells, and possibly in the process of phototransduction of in­ vertebrates.
The Oxygen Sensitivity of Nitrogenase in Rhodobacter capsulatus: Repression and Inactivation
Authors: Klein Gesine , Jahn Andreas , Steindorf Astrid , Klipp Werner , Oelze Jürgen 
Published: August 2018

Abstract
In chemostat cultures of Rhodobacter capsulatus, growing aerobically in darkness, in situ nitrogen fixation occurred at significantly lower oxygen concentrations than the acetylene reduction activity of nitrogenase, as determined with samples from the culture under opti­ mum assay conditions. In contrast to nitrogenase of cultures growing diazotrophically at low oxygen, nitrogenase present in inactive form at the higher oxygen concentrations could not be activated to fix nitrogen by increasing i.) the energy supply by illuminating the cultures, ii.) the supply of cells with electron donor and iii.) cellular respiration. These results suggest that oxygen controls cellular nitrogen fixation directly rather than indirectly by interfering with the general metabolism. On this basis, the sensitivity toward oxygen of nif gene expression as well as of nitrogenase polypeptide accumulation was studied. The nifH promoter was active up to about 40% air saturation, exhibiting a biphasic sensitivity to oxygen, i.e. steep decreases in activity between 1 to 2% and between 10 to about 20% air saturation. A similar behaviour was observed with respect to cellular levels of both polypeptides of component 1 (Rc1) of nitrogenase, which were accumulated up to about 20% air saturation. Component 2 (Rc2) was less oxygen-sensitive than Rc1, its steady state level reached a maximum at 2% air saturation. A sudden increase in the ambient oxygen concentration, i. e. oxygen stress, revealed that, in vivo, nitrogenase was fairly stable against oxygen damage. Modification of Rc2 by ADP-ribosylation occurred under ammonium shock conditions, regardless of whether the cells fixed nitrogen or not. But it was not observed with cultures growing aerobically in the dark at steady state or under oxygen stress. Results obtained with mutant W107I of R. capsulatus lacking the modifying/demodifying enzymes supported the conclusion that modifi­ cation of Rc2 was not required for the inactivation of nitrogenase by oxygen.
Isolation, Characterization, and Substrate Specificity of the Plasma Membrane ATPase of the Halophilic Archaeon Haloferax volcanii
Authors: Steinert Kerstin , Bickel-Sandkötter Susann 
Published: August 2018

Abstract
Isolated membranes of the moderate halophilic bacterium Haloferax volcanii are able to hydrolyze ATP via an ATPase, which needs the presence of Mg2+ or Mn2+, high concentra­ tions of NaCl, a pH value of 9, and high temperatures with an optimum at 60 °C. We have not found any phosphatase activity in the preparations. We developed a purification method for the isolated enzyme with an enrichment factor of 90. SDS-gel electrophoresis of the partially purified enzyme of Haloferax volcanii showed putative ATPase subunits of 63, 51, 37, and 12 kDa. N-ethylmaleimide (NEM) a specific inhibitor for V-ATPases, which alkylates cysteines, inhibited the enzyme slightly. Binding of tritiated NEM to the isolated ATPase fractions resulted in labelling of the 63 and 51 kDa peptides. Using PCR with degenerate oligonucleotides, we could clone and sequence a gene cluster encoding the Aj part of the halophilic ATPase. The described genes are organized in an operon in the order D. C, E, B, A , named alphabetically according to their decreasing size. The deduced products of 64.5, 52, 38.7, 22, and 11.6 kDa confirm the results of the partial purification of the ATPase. Biochemical characterization of the Haloferax volcanii ATPase gave the following results: In presence of Mn2+ higher rates of ATP hydrolysis could be observed than in presence of Mg2+, but free manganese ions inhibited the enzyme activity of the ATPase. Calculation of the true concentrations of the complex between ATP and the respective divalent metal ion led to determination of Michaelis-Menten constants for ATP in the hydrolysis direction of 1 mм in presence of MgCl2 and 0.24 mм in presence of MnCl2. Sodium chloride concentrations in the molar range induce changes in K M by a factor of about 10. The enzyme is specific for ATP; other nucleotides including GTP and ADP are competitive inhibitors of ATP hy­ drolysis.
Toxicity of Palicourea marcgravii: Combined Effects of Fluoroacetate, N-methyltyramine and 2-Methyltetrahydro-β-carboline
Authors: Kemmerling Wilhelm 
Published: August 2018

Abstract
Feeding experiments carried out with cattle and horses could prove the toxic effects of P. marcgravii (Rubiaceae) in all cases. The typical symptoms of “sudden death”, however, are observed in ruminants only. This difference could not be explained so far. A part from fluoroacetate, two more substances also have influence the toxic effects and have been isolated from P. marcgravii for the first time: N-methyltyramine and 2-methyltetra-hydro-β-carboline (2-Me THBC). Structure elucidation of these compounds is mainly accom­ plished by 1H-NM R, 13C-NMR and MS techniques. Due to the small quantity of fluoroacetate (5.4 μg/g plant), the main toxic effect obviously lies in the two discovered substances. In contrast to the slow death of horses (monogastriers), the “sudden death syndrome” of cattle (ruminants) can be explained as a result of the higher resorbility of these two substances in the gastro-intestinal system. Given orally, both substances influence the monoamine oxidase type A (MAO-A): N-methyltyramine acts as a competitive substrate, and 2-Me THBC is one of the most effective MAO-A-inhibitors. Thus, the decomposition of the specific MAO-A-substrates noradrenaline and adrenaline as well as of N-methyltyramine itself is inhibited. The α-and β-receptors of the sympathetic system are stimulated more strongly, which leads to a drastic rise in blood pressure and thereby to a more rapid distribution of fluoroacetate in the body. This results in a reinforced input of fluoroacetate in the cells of especially active organs of the body (heart etc.). Thus, even smaller quantities of fluoroacetate are lethal.
Effect of Mg2+-ATP on Acetylcholinesterase of Electrophorus electricus (L.)
Authors: Matta A. Nery da , Silva C. B. , Hassón-Voloch A. 
Published: August 2018

Abstract
The effect of Mg2+-ATP on purified acetylcholinesterase (AChE) from electric tissue of Electrophorus electricus (L.) was studied. The enzymatic activities were measured with acetylcholine and acetylthiocholine as substrates. The kinetic parameters Vmax, Km and Hill coefficient (nH), for acetylcholine and acetylthiocholine were modified with Mg2+-ATP. It was shown that acetylcholinesterase presents an apparent activation at high concentration of substrates and an inhibition in the presence of Mg2+-ATP at low concentration of acetylcho line and acetylthiocholine. In addition, the data suggest that Mg2+-ATP induced an allosteric modulation of the acetylcholinesterase obtained from Electrophorus electricus (L.), and indi­cate an active adenosine triphosphate participation during cholinergic activity.
Bimodal Effect of Amphiphilic Biocide Concentrations on Fluidity of Lipid Membranes
Authors: Podolak Marian , Man Dariusz , Waga Stanislaw , Przestalski Stanislaw 
Published: August 2018

Abstract
Using the spin label method (ESR) it has been shown that biologically active, amphiphilic compounds (quaternary ammonium salts -AS) containing polar heads with single and double positive charge caused, at low concentrations, decrease fluidity of liposome membranes formed with egg yolk lecithin (EYL). At higher concentrations an increase in fluidity was observed. With compounds having a single positive charge minimum fluidity of membrane structure occurs in the range of 1 to 3%, with compounds containing double positive charge -in the range of 4 -6 % . That effect does not depend on polar head size and length of alkyl chains of the AS used. Analysis of the electrostatic interaction between positive charges and dipole system suggest that at low ion concentrations the binding energy of the system increases, while it decreases at high concentrations. For the model presented, maxi­mum of binding energy of the system occurs at 3% of positive monovalent ions and at 6% of positive divalent ions admixed.
Structure Elucidation of Azotobactin 87, Isolated from Azotobacter vinelandii ATCC 12837*, **
Authors: Schaffner E. M. , Hartmann R. , Taraz K. , Budzikiewicz H. 
Published: August 2018

Abstract
Chromopeptide siderophores (azotobactin 87-1 and -II) were isolated from an iron deficient culture medium of Azotobacter vinelandii ATCC 12837 (=DSM 87). Their structures were elu­ cidated by chemical degradation studies and spectroscopic methods, especially 2D-NMR-tech-niques. Total assignments of 1H-, 13C-, and 15N-resonances based on 2D-HOHAHA-, 1H/13C-HMQC-, 1H /13C-HMBC-, 1H /15N-HMQC/TOCSY-, and 1H/15N-HMBC-experiments are given as well as sequential information derived from 1H/1H-NOESY-, 1H /13C-HMBC-and 1H/ 13N-HMBC-experiments. Both Az 87-1 and Az 87-11 consist of a tetracyclic chromophore -(1S)8,9-dihydroxy-4-oxo-2,3,4,5-tetrahydro-1H,10cH-3a,5,10b-triazaacephenantrylene-1-carb-oxylic acid -and a decapeptide chain linked with the N-terminus to the carboxy group of the chromophore containing also modified, non-proteinogenic amino acids. The sequence L-Ser-D-Ser-L-Hse-Gly-D-threo-OHAsp-Hse-Hse-Hse-D-N5OH-N5-R-Hbu-Om-L-Hse was determined for Az 87-1, while Az 87-11 contains a C-terminal L-Hse-lactone instead. Iron is chelated by the catecholic group of the chromophore, the β-hydroxy aspartic acid, and the hydroxamate function formed by N5-hydroxyornithine and R-β-hydroxybutyric acid.
Effect of Amphiphilic Cationic Compounds on Calcium Ion Desorption from Lecithin Liposome Membranes. Kinetic Studies and Quantum Chemical Calculations
Authors: Kuczera Janina , Chojnacki Henryk , Kral Teresa E. , Przestalski Stanislaw 
Published: August 2018

Abstract
The effect of four amphiphilic cationic compounds that differ in their polar head properties on the kinetics of calcium ion desorption from unilamellar lecithin liposom e membranes has been studied. The compounds under investigation were: N-benzyl-N,N-dimethyl-N-tetradecy-lammonium chloride (BDTA), N-methyl-N-tetradecylmorpholinium bromide (MTM), N-methyl-N-dodecyloxym ethylenem orpholinium chloride (MDOM) and N,N,N-trimethyl-N-te-tradecylammonium bromide (TMTA). Kinetic constants were determined using the three-compartmental analysis for isotopic labels. For the above mentioned compounds electronic structure calculations were performed and point charges and dipole moments of the molecules determined by using quantum chemis­try methods. It was found that the rate of desorption increases with increasing concentration of the compounds studied, and effectiveness of the compounds follows the sequence: BDTA >MTM >TMTA >MDOM . For dipole moments the sequence obtained is somewhat different, namely: BDTA>MTM >MDOM >TMTA. Apparently, the differences in the effectiveness of action of the compounds in the calcium desorption process follow not only from the values of dipole moments of their polar heads but also from the values of point charges on some atoms and from steric properties.
Lipophilic Exudate Constituents of Some Rosaceae from the Southwestern USA
Authors: Wollenweber Eckhard , Henrich Birgit , Mann Karin , Roitman James N. 
Published: August 2018

Abstract
The lipophilic epicuticular material of four shrubby Rosaceae from the Southwestern USA has been studied. They all exhibit triterpene acids as major products. Adenostomci sparsifolium and Cowania mexicana var. glaber, the two species in which glandular structures and a lipophilic excretion are obvious, produce free flavonoid aglycones as well. In Adenostoma, most of these are very rare com pounds. Cowania exhibits some trivial and one rare flavone. In Cercocarpus montanus var. glaber and in Fallugia paradoxa the epicuticular material is devoid of flavonoids.
Species-Specificity of an Elicitor-Active Oligosaccharide, LN-3, to Leguminous Plants
Authors: Tai Akihiro , Kawazu Kazuyoshi , Kobayashi Akio 
Published: August 2018

Abstract
LN-3, a linear pyridylaminated hepta-β-glucoside previously found to show elicitor activity in alfalfa cotyledons, was examined for phytoalexin-inducing activity in pea epicotyl and bean cotyledon assays. LN-3 did not show (+)-pisatin-inducing activity in pea epicotyls. In the bean cotyledon assay, however, the (± )-kievitone content gradually increased with increasing LN- 3 concentration, and reached a maxim um (ca. 17 |ig/g fresh wt) at 100 μ/ml. Half-maximal elicitor activity was seen at ca. 16 μm . After three legumes, alfalfa, pea and bean, were treated with LN-3, the recovery of the rem aining LN-3 or its fragments was examined. Almost 100% of LN-3 or its fragments was recovered from the pea test solution; in contrast, recoveries from alfalfa and bean were only 63.8 and 38.1% , respectively. HPLC and LC-MS analyses of the recovered samples indicated that LN-3 was hydrolyzed to give mono- and/or diglucoside( s) in the alfalfa and the bean solutions, while in the pea experiment a small portion of LN-3 was hydrolyzed to give sugar fragments with different degrees of polymerization < 7.
Radiation-Induced Apoptosis in Thymocytes: pH Sensitization
Authors: Ojeda F. , Skardova I. , Guarda M.I. , Maldonado C. , Folch H. 
Published: August 2018

Abstract
Thymocytes were used as a model system to study the effect of microenvironmental pH changes on the radiation-induced apoptosis. We found that the sensitivity of thymocytes toward radiation induced apoptosis is increased by increasing the pH of the incubation me­dium. The major sensitivity change occurs between pH 7 and 8.
In a given cell suspension the results obtained where similar when the apoptosis evaluation was carried out either by counting the picnotic nuclei, or monitoring the fraction of apoptotic nuclei by flow cytometry; both methods show a radiosensitization when the pH value of incubation media rises from 7 to 8. These results may be important when “in vitro” experiments are performed with lymphoid cells, since changes in pH of the media may determine important changes in the results.
Painting of Human Chromosome 8 in Fifteen Minutes
Authors: Durm Markus , Hausmann Michael , Aldinger Klaus , Ludwig Horst , Cremer Christoph 
Published: August 2018

Abstract
The technique of chromosome-in-situ suppression (ClSS)-hybridization (chromosome painting) has now been well established. However, all standard protocols so far require long renaturation times (typically 12 hours and more). Here, we describe a new, extremely fast pro­tocol for chromosome painting using a commercially available, directly fluorescence labelled probe for chro­mosome 8. The hybridization conditions used omit separate preannealing procedures and denaturing chemical agents. The renaturation time required for chromosome painting was reduced to 15 minutes. In addition, most washing steps were eliminated. As a consequence, the entire painting procedure was feasible in less than half an hour.
Preparation of [14C]-Labelled 1,2,3,4,6-Penta-O-Galloyl-β-ᴅ-Glucose and Related Gallotannins
Authors: Rausch Hans , Gross Georg G. 
Published: August 2018

Abstract
[U -14C]-Labelled 1,2,3,4,6-penta-O-galloyl-β-ᴅ-glucose was prepared by photoassimilation of 14CO2 with leaves from staghorn sumac (Rhus typhina) in the presence of the herbicide glyphosate. Extracts of the plant material were partitioned against ethyl acetate and chromatographed on Sephadex LH-20, yielding a series of crude tri-to decagalloylglucoses. The pentagalloylglucose fraction among these was further purified by HPLC to >99% purity and a specific radioactivity of 130 kBq (3.5 μCi) per μmol. The ratio of the radioactivities in the glucose and galloyl moieties, respectively, suggested a uniform labelling pattern of the product.
A New Non-Radioactive Assay of Phytoene Desaturase to Evaluate Bleaching Herbicides
Authors: Sandmann Gerhard , Schneider Christian , Böger Peter 
Published: August 2018

Abstract
A non-radioactive cell-free assay was developed to quantitatively determine inhibition of plant-type phytoene desaturase by bleaching herbicides. An active desaturase was prepared from an appropriately cloned E. coli transformant. Another E. coli transformant was used to produce the required phytoene. Phytofluene and t-carotene, the products of the desaturase reaction, were either determined by HPLC or optical absorption spectra. Enzyme kinetics and inhibition data for the bleaching tetrazole herbicide WL110547 are presented as an example.
Antiulcerogenicity of the Flavonoid Fraction from Erica andevalensis Cabezudo-Rivera
Authors: Reyes M. , Martín C. , Lastra C. Alarcón de la , Trujillo J. , Toro M. V. , Ayuso M. J. 
Published: August 2018

Abstract
Investigations were carried out to determine the antiulcerogenicity of the flavonoid fraction (ethyl acetate extract) of Erica andevalensis Cabezudo-Rivera on gastric ulceration induced by different experimental models. Oral treatment with the ethyl acetate extract and the major flavonoid (myricetin 3-O-ᴅ-galactoside) were found to be effective to prevent gastric ulceration induced by cold-restraint stress in rats . Statistically significant ulcer index values with respect to the control group were observed. Mucus content was not increased although it was accompanied by an increase in proteins and hexosamines. In pyloric-ligated animals flavonoids showed a significant reduction in the number and severity of the ulcers. Under the same conditions acidity did not decrease with the flavonic extract and myricetin 3-O-ᴅ-galactoside significantly as compared to control. Gastric ulcers induced by oral administration of absolute ethanol were reduced by pretreatment with the flavonoid extract of doses from 125 to 250 mg/kg and the isolated flavonoid of 25 mg/kg p.o. However neither the flavonic extract nor the isolated flavonoid induced changes in the amount and glycoprotein content of gastric mucus.
Effects of Fraxetin on Glutathione Redox Status
Authors: Martín-Aragón Sagrario , Benedí Juana M. , Villar Angel M. 
Published: August 2018

Abstract
We have evaluated the effects of an oral treatment of mice with fraxetin (25 mg/kg for 30 days) on the glutathione system (GSH, GSSG, and GSSG/GSH ratio as stress index), glutathione reductase (GR) and glutathione peroxidase (GPx) in liver supernatants from male C57BL/6J mice (18-month old). A significant antioxidant effect in vivo was found under this treatment by a decrease in the GSSG/GSH ratio and an increased activity of GR compared with the control mice. GSSG rate and GSSG/GSH ratio were correlated with the decline of GPx activity. Our results of increased GR activity could be considered as a supercompensation in glutathione redox status that involves a decrease in the accumulation of GSSG, as well as, in GSSG /GSH ratio. Finally, we suggest that this possible mechanism of supercompensation could lead to an enhancement in the average life span.
Surface Lipids of the Silverfish (Lepisma saccharina L.)
Authors: Jacob Jürgen , Raab Gottfried , Hoppe Udo 
Published: August 2018

Abstract
Surface lipids obtained from the silverfish by short-term solvent extraction contain ali­ phatic hydrocarbons, monoester waxes, cholesteryl esters, triglycerides, free cholesterol, and free fatty acids. Together, cholesteryl esters and free cholesterol account for >30% of the total lipids.
As found for other arthropods living in aquatic or moist environments unsaturated homologues predominate among the acidic constituents.
The cuticular lipid composition o f silverfish resembles that of other more primitive arthropod forms such as stoneflies and dragonflies.
The Structure of Preen Gland Waxes from Pelecaniform Birds Containing 3,7-Dimethyloctan-1-ol -an Active Ingredient against Dermatophytes
Authors: Jacob Jürgen , Eigener Ulrich , Hoppe Udo 
Published: August 2018

Abstract
A biologically active principle has been isolated from the uropygial gland secretion of the gannet (Sula bassana) exhibiting growth inhibitory activity for Gram-positive bacteria, yeasts, moulds and, in particular, for dermatophytes.The feather lipids of this species consist of monoester waxes predominantly composed of 3,x-dimethylalkanols esterified with fatty acids belonging to homologous series of 2-and 3-methyl-, 2,x-and 3,x-dimethyl-as well as 2,x,y-and 3,x,y-trimethyl-substituted alkanoic acids. For chemosystematic reasons other pelecani­ form species (Pelecanus crispus, Pelecanus onocrotalus, Phaeton lepturus) and one gaviiform species (Gavia stellata) have also been analysed. The pattern of their preen wax constituents suggest to assume that the Pelecaniformes are polyphyletic with gannets and cormorants being closely related, whereas pelicans and tropic birds are different, both from the former and from each other. Pelicans resemble very much the grebes, while tropic birds seem to be more closely related to the charadriiform, alciform, and possibly to the gaviiform birds.