bluuebunny/crossref_metadata_2025 huggingface dataset:
Potent Free Radical Scavenging Activity of Propol Isolated from Brazilian Propolis
Authors: Basnet Purusotam , Matsuno Tetsuya , Neidlein Richard
Published: August 2018

We evaluated free radical scavenging activity of the water, methanol and chloroform ex­tracts of propolis in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical and xanthine-xanthine oxidase (XOD) generated superoxide anion assay systems. The free radical scavenging activity guided fractionation and chemical analysis led to the isolation of a new compound, propol {3-[4-hydroxy-3-(3-oxo-but-1-enyl)-phenyl]-acrylic acid) from the water extract, which was more potent than most common antioxidants such as vitamin C and vitamin E (α-tocopherol) in these assay systems.
Organic Acid Production by Propionibacterium shermanii: Effect of pH, Temperature and Vitamin-Nitrogen Source
Authors: Quesada-Chanto A. , Schroeder A . G. , Schmid-Meyer A. C. , López J. A. , Silveira M. M. , Jonas R.
Published: August 2018

Production of propionic acid by Propionibacterium shermanii CDB 10014 was enhanced by a pH value of 6.5 and by temperatures in the range 35-37 °C. Depending on the type of yeast extract, succinic acid can be produced in higher proportions, with decreasing propionic acid yields. With respect to propionic acid production, Difco yeast extract has shown the best results when yeast extract preparations from other different suppliers were compared. To replace yeast extract by a cheaper vitamin-nitrogen source, corn-steep liquor was tested. A complete depletion of glucose was achieved, yielding a final propionic acid concentration of over 35 g/l. These results are even better than those obtained with Difco yeast extract and suggest the possibility of an economical process based on corn-steep liquor.
Stimulation of Pancreatic Lipase Activity by Saponins Isolated from Medicago sativa L.
Authors: Sroka Zbigniew , Jurzysta Marian , Tylcz Joanna , Rządkowska-Bodalska Halina
Published: August 2018

Saponins isolated from Medicago sativa L. appeared to stimulate lipolytic activity and did not influence amylolytic or proteolytic activity of Neopancreatinum (extract of pancreatic enzymes: lipase, proteases and amylases). Saponins isolated from the aerial part of Medicago sativa L. were demonstrated to stimulate lipase activity more effectively than saponins sepa­ rated from the root of this plant. When saponins were treated with 0.02 m HC1 at 37 °C for 1 hour their lipase stimulation ability did not change. The saponins stimulated Neopancreatinum lipolytic activity more in­ tensively in the presence of sodium cholate.
Involvement of Cyclic Adenosine Monophosphate in the Regulation of Pupal Color Adaptation of the Butterfly, Inachis io
Authors: Starnecker Gerhard
Published: August 2018

In the butterfly Inachis io, a pupal melanization reducing factor (PMRF) which is located throughout the entire central nervous system controls the intensity of pigmentation of pupal cuticle depending on the background color of the pupation site. PMRF does not only reduce melanization but, in addition, enhances lutein incorporation in a dose-dependent manner to form pupae with yellow color on bright backgrounds.

The present paper reports on the effects on pupal pigmentation caused by cyclic nucleo­ tides and phosphodiesterase (PDE) inhibitors which prevent degradation of cyclic nucleo­ tides. The injection of cAMP did not alter pupal coloration whereas its membrane-permeable analog dibutyryl-cAMP mimicked dose-dependently PMRF activity. Thus, pupae of reduced melanization and, in addition, enhanced yellow coloration were formed. This indicates that an increased intracellular cAMP level is capable of mediating PMRF effect. Also, the injection of the PDE inhibitor isobutylmethylxanthine (IBMX) caused dose-dependently pupae of reduced melanization and enhanced lutein incorporation.

Theophylline (another PDE inhibitor) was only slightly effective (23% inhibition of melanization) at the highest dose compared to IBMX. The injection of cGMP and its analog dibutyryl-cGMP exhibited no melanization reducing effect.

Extracts of abdominal ganglia (AG) which contained PMRF activity caused significantly brighter pupae when injected in combination with IBMX. However, this stimulation by IBMX became no longer effective at higher AG doses. Therefore, the present results are suggestive of an involvement of cAMP as a second messenger in the action of PMRF on pupal color adaptation.
Biotyping of Campylobacter Strains Isolated in Lagos, Nigeria Using the Modified Preston Biotype
Authors: Smith S. I. , Coker A. O. , Olukoya D. K.
Published: August 2018

Fifty-eight Campylobacter strains were isolated from children with diarrhoea at various health centres in Lagos and from healthy chicken. Twenty -nine strains of Campylobacter were isolated from humans, while the same number were isolated from chicken. The strains were biotyped using the modified Preston biotype scheme. The Preston biotyping results have been compared with the results of Penner serotyping. Out of fifty-eight strains studied, the technique identified ten strains (17%) as C. coli, three (5%) as C. lari and fourty-five (78%) as C. jejuni, by the coding system. This technique identified twenty-eight Campylo­ bacter species. This method highlights the usefulness of this technique in the biotyping of local strains, however, when the two schemes are used in combination they give excellent typing results suitable for epidemiological purposes.
Triterpenoids from Acaena pinnatifida R. et P
Authors: Valcic Susanne , Wächter Gerald A. , Montenegro Gloria , Timmermann Barbara N.
Published: August 2018

Eight urs-12-ene triterpenoids, β-sitosterol, (+)-catechin, and apigenin 7-O-glucoside were isolated from the leaves of Acaena pinnatifida R. et P. The triterpenoids were characterized as pomolic acid, pomolic acid-3-acetate, tormentic acid, 2-epi-tormentic acid, euscaphic acid, tormentic acid glucoside, niga-ichigoside F1, and niga-ichigoside F2.
Additional Sulfur Compounds from the Anal Glands of the Striped Polecat, Ictonyx striatus (Mustelidae, Mammalia)
Authors: Wheeler J. W. , Nyalley L. , Davis D. M. , Weldon P. J.
Published: August 2018

Two sulfur compounds have been identified in the anal gland secretions of captive-raised adults of the striped polecat (Ictonyx striatus), an African mustelid. 3-Ethyl-1,2-pentanedithiolane was observed in the secretions of an adult male and an adult female. 1,3-Pentanedithiol was observed in the male; this compound has not previously been reported from mustelid anal glands.
Pulvinatal, a Novel Bioactive Metabolite from the Basidiomycete Nidularia pulvinata (Schw.) Fr.
Authors: Becker Uta , Erkel Gerhard , Kocksch Gunter , Anke Timm , Sterner Olov
Published: August 2018

Pulvinatal (1) was isolated from fermentations of Nidularia pulvinata as an inducer of differentiation of HL -60 promyelocytic leukemia cells. Its structure was elucidated by spectroscopic methods. In addition, N. pulvinata was found to produce 2,4,5-trihydroxy-6-methyl-benzenecarbaldehyde (2) and orsellinic acid (3). Pulvinatal exhibits weak antifungal and only marginal cytotoxic activities.
Intracellular Localization of Two Betaine Lipids by Cell Fractionation and Immunomicroscopy
Authors: Department of Chemistry and Biochemistry, University of Bern K. , Department of Chemistry and Biochemistry, University of Bern W. , Faculty of Biology, University of Bielefeld, Germany A.
Published: August 2018

The cellular localization of the betaine lipids diacylglyceryl-N,N,N-trimethylhomoserine (DGTS) and diacylglycerylhydroxymethyl-N,N,N-trimethyl-β-alanine (DGTA) was investi­ gated by a) chemical analysis of subcellular fractions and b) immunochemical methods using specific antisera and either fluorescence microscopy or electron microscopy for detection of the label. A homogenate of Lycopodium annotinum (Pteridophyta) was fractionated by differential and density gradient centrifugation. The particulate fractions obtained were analyzed for chlorophyll, cyt c oxidase, NADH-cyt c reductase and DGTS. Non-plastidial fractions were enriched in DGTS and only minor amounts of this lipid could be attributed to chloroplasts. Anti-DGTS and anti-DGTA sera were produced by immunization of rabbits. The monospecificity of the antisera was examined with cells of Chlamydomonas reinhardtii (Chlorophyceae) containing DGTS, Pavlova lutheri (Haptophyceae) containing DGTA and Ochromonas danica (Chrysophyceae) containing both DGTS and DGTA. Euglena gracilis which is free of betaine lipids, was used as a control. For the test, a FITC-coupled goat anti-rabbit antibody was used and detected by fluorescence microscopy. Thin sections of Ochromonas and Pavlova were incubated first with the anti-lipid sera and subsequently with a gold-coupled anti-rabbit serum and then examined in the electron microscope. With O chro­ monas, anti-DGTS as well as anti-DGTA sera gave an accumulation of gold label in the cytoplasmic space but not in the chloroplasts. Similar results were obtained with Pavlova using anti-DGTA serum. These results describe for the first time the cytochemical localiza­ tion of DGTS and DGTA strongly suggesting both these lipids to be associated mainly with non-plastidial structures.
OH-Radical-Type Reactive Oxygen Species Derived from Superoxide and Nitric Oxide: A Sensitive Method for their Determination and Differentiation
Authors: Hippeli Susanne , Rohnert Ute , Koske Dagmar , Elstner Erich F.
Published: August 2018

Reactive oxygen species are involved in many diseases where the radical species OH . peroxynitrite and the non-radical, hypochlorous acid, play an outstanding role. The formation of OH -type oxidants is essentially confined to a few types of reactions. The most prominent ones are the one-electron reduction of hydrogen peroxide by Fe2+ or Cu+- ions (Fentontype reactions), reaction of hypochlorite with superoxide and finally formation and decay of peroxynitrite (ONOOH), formed from superoxide and NO. In this communication we wish to report on a simple model system allowing to differentiate between these ROS: ethene formation from ACC is only detectable in the presence of hypochlorite (v. Kruedener et al., 1995) and not detectable with Fenton-type oxidants or SIN-1 (3-morpholinosydnonimine, a peroxynitrite generator by releasing sequentially superoxide and NO) at 10 |.im concentrations. On the other hand, ethene formation from KMB is negligible in the presence of hypochlorite but proceeds rapidly with Fenton-type oxidants (4 μᴍ H2O2; 4 μᴍ Fe2+) as well as with 1 μᴍ SIN-1. Stimulation of Fenton-type oxidants and not of SIN-1 by EDTA and characteristic patterns of inhibition by SOD, catalase. hemoglobin and uric acid allow a differentiation between these two potential precursors of OH-radicals. Synthetic ONOOH shows different reaction kinetics as compared to SIN-1. Inhibition of ONOOH-dependent ethene formation by different compounds occurs more or less “random” indicating an unspecific influence of proteins and also small molecules. Comparism of the individual inhibition types of several selected compounds allows a differential analysis as to the generation pathway of the final oxidants, OH- radical or peroxynitrite
Blue Light Mediated Photoreduction of the Flavoprotein NADPH-Cytochrome P450 Reductase. A Förster-Type Energy Transfer
Authors: Müller-Enoch Dieter
Published: August 2018

The absorption spectra and the corresponding molar absorption coefficients of the fluorophores umbelliferone, FAD and FMN and of the FAD and FMN containing flavoprotein NADPH-cytochrome P450 reductase of different oxydation-reduction states are documented. Binding spectra of the ligand umbelliferone with the CYP2B1: NADPH-cytochrome P450 reductase-complex were determined by difference spectroscopy. The Scatchard plot of the equilibrium ligand binding shows a high affinity part and a low affinity part of 12 and 34 umbelliferone binding sites per CYP2B1: reductase-complex molecule, respectively The fluorescence excitation and emission spectra of the donor molecule umbelliferone and the acceptor molecules FAD and FMN are given. The fluorescence spectra of the reaction components under test conditions of CYP2B1-dependent 7-ethoxycoumarin-O-deethylase are measured. The excitation energy transfer from the donor umbelliferone (λE=380 nm; λF= 460 nm) to the acceptor molecule FMN (λE=465 nm; λF=525 nm) was examined under assay conditions. The results dem onstrate that a radiationless Förster-type energy transfer takes place in the presence of the CYP2B1: reductase-complex. It turned out that this effect is a function of the protein complex-concentration. The data presented here combined with previously made observations by Müller-Enoch (Müller-Enoch D. (1994), Z. Naturforsch. 49c, 763-771) support the finding that the umbelliferone molecules, n = 12-34, bound per mole of CYP2B1: reductase-complex, transfer their absorbed light energy radiationless to the FAD binding domain. The complex formed containing 12 or 34 molecules of umbelliferone provides absorption coefficient values at λ= 380 nᴍ of 78 and 221 mᴍ-1 · cᴍ-1 , respectively. The Förster-type energy transfer from the donor umbelliferone to the acceptor FAD not only leads to a light activation of the singlet state of FAD but also to a conformational change of the amino acids close to the FAD binding side to favour the encaging of the FAD* triplet state which reacts with the NADPH to form the FADH2 reductase. Due to this process the overall reaction can start with the unquenched excited FAD* triplet state as an interm ediate which is about 30 kJ/mol lower in energy than the dark reaction
Production of OH-Radical-Type Oxidant by Lucigenin
Authors: Heiser Ingrid , Muhr Angelika , Elstner Erich F.
Published: August 2018

In the presence of NADH- reductases (dihydrolipoamide: NAD oxidoreductase E. C.l.8.1.4 from pig heart or from Clostridium kluyveri; frequently also addressed as “diaphorases”) and NADH lucigenin strongly increases ethylene production from a-ketomethylthiobutyrate (KMB) as an indicator for strong oxidants of the OH-radical type. These reactions are further stimulated in the presence of Fe3+ ions. With these NADH- “diaphorases”, the structurally similar poison, paraquat, in the absence or presence of Fe3+ has no effect. With ferredoxin-NADP reductase (E. C.1.18.1.2.), however, paraquat reacts quasi identical to lucigenin. Superoxide dismutase, catalase, free radical- or OH - scavengers such as mannitol, propylgallate, DABCO, and desferal inhibit the reaction whereas EDTA (in the presence or absence of added Fe3+) is stimulatory. From these data we conclude that the superoxide - indicator LUC is redox-active after unspecific coupling to several almost ubiquitory NAD(P)H- reductases catalyzing monovalent oxygen reduction. Lucigenin thus should no longer be used as a “specific” superoxide indicator. This report is in agreement with very recent results by Liochev and Fridovich (Arch. Biochem. Biophys. 337, 115 [1997]) and Vasquez-Vivar et al. (FEBS Lett. 403, 127 (1997).
Anti-Oxidant Mechanisms Involved in Gastroprotective Effects of Quercetin
Authors: Martín M. J. , La -Casa C. , Alarcón-de-la-Lastra C. , Cabeza J. , Villegas I. , Motilva V.
Published: August 2018

The anti-ulcerogenic and anti-oxidant effects of various flavonoids have been frequently reported. We investigated the cytoprotective properties of quercetin, a natural flavone, in gastric mucosal injury induced by 50% ethanol, since in this experimental model the patho­genesis of the lesions has been related with production of reactive oxygen species. The in­volvement of neutrophil infiltration and the capacity of this flavonoid to restrain the oxida­tive process produced in the gastric tissue after ethanol administration were also investigated. Oral pretreatment with the highest dose of quercetin (200 mg/kg), 120 min before absolute ethanol was the most effective anti-ulcer treatment. Thiobarbituric acid reactive substances in the gastric mucosa, an index of lipid peroxidation, were increased by ethanol injury, but the increase was inhibited by the administration of 200 mg/kg of quercetin. This dose also induced a significant enhancement in the levels of mucosal non-protein SH compounds (im­portant anti-oxidant agents) and in glutathione peroxidase activity. Exposure of the gastric mucosa to 50% ethanol induced a significant increase in myeloperoxidase activity, an index of neutrophil infiltration. Flowever, quercetin was not able to modify the increase in enzy­matic activity generated by the necrotizing agent. The activity of superoxide dismutase enzyme involved in several antioxidant processes was also not significantly modified after quer­cetin treatment.

These results suggest that the anti-ulcer activity of quercetin in this experimental model could be partly explained by the inhibition of lipid peroxidation, through decrease of reactive oxygen metabolites. However, the inhibition of neutrophil infiltration or the increase of superoxide dismutase activity does not appear to be involved in gastroprotective effect of this flavonoid.
Thyroid Hormone-Induced Changes in Cytoplasmic and Mitochondrial Proteins of a Teleost
Authors: Tripathi G.
Published: August 2018

The effect of triiodothyronine (T3) on the cytoplasmic and mitochondrial protein contents were studied in the liver and skeletal muscle of a freshwater teleost. The fish exposed to thiouracil for 28 days showed 1.5-2 times reduction in the total protein contents of cytoplasmic and mitochondrial fractions. A single injection of T3 to thiouracil exposed fish caused the earliest induction in the liver and skeletal muscle mitochondrial protein and the skeletal muscle cytoplasmic protein at 12 hr of lapses. However, the initial induction in the cytoplasmic protein of the liver was observed at 3 hr after T3 treatment. The maximum inductions (1.5-3.2 fold) in the cytoplasmic and mitochondrial proteins of the liver and skeletal muscle were obtained at 1 8 -2 4 hr following hormonal administration. Thereafter, the cytoplasmic and mitochondrial protein contents of both the tissues declined to their control levels within 3 6 - 4 8 hr of T3 injection which reflected the half-life and turnover period of the induced proteins. These T3 dependent inductions in the cytoplasmic and mitochondrial proteins of the liver (1 .4 -3 .2 fold) and skeletal muscle (1.8 -2.7 fold) were inhibited by actinomycin D and cycloheximide indicating T3-induced de novo synthesis of the proteins. The induction in the cytoplasmic protein (3 fold) was almost double to that of the mitochondrial protein (1.6 fold) suggesting more synthesis of protein molecules in the cytoplasm for cellular and subcellular activities.
Interaction of Histone H1 with cis-Platinum Modified DNA
Authors: Paneva Elena G. , Spassovska Nadejda C. , Grancharov Konstantin C. , Zlatanova Jordanka S. , Yaneva Julia N.
Published: August 2018

Cis-diamminedichloroplatinum(II) (cis-DDP) is known as an effective anticancer drug. Its therapeutic effect is supposed to be a consequence of the covalent binding to DNA. A number of cellular proteins were found to bind selectively to DNA modified by cis-DDP (but not by its isomer frans-DDP). Here we present our observations on interaction of the linker histone H1 with cis- and trans-DDP modified DNA fragments. The results afford new experimental information about the preferential binding of histone H1 to cis-DDP-distorted DNAs versus trans-DDP modified ones.
Nuclear Magnetic Resonance and Mass Spectrometric Studies on the Action of Proteases on Pig Articular Cartilage
Authors: Schiller Jürgen , Arnhold Jürgen , Arnold Klaus
Published: August 2018

Rheumatic diseases are accompanied by a progradient diminution of the cartilage layer. Unfortunately, degradation mechanisms (role of different enzymes and reactive oxygen spe­cies) are not yet understood. Since nuclear magnetic resonance (NMR) spectroscopy was often used for the investigation of synovial fluids, the aim of the present work was to detect cartilage degradation products upon proteolytic digest of cartilage. Cartilage samples were incubated at 37 °C with phosphate buffer in the absence or pres­ence of different proteases (collagenase, trypsin and papain). Supernatants were subsequently assayed towards their content of carbohydrate and protein degradation products by NMR (1H-and 13C-) and MALDI-TOF mass spectrometry. Intense resonances of relatively mobile N-acetyl side chains (ca. 2.01 ppm) of polysaccha­ rides of cartilage were only detectable on digestion with papain. The appearance of these resonances indicates intense degradation of the core protein of proteoglycan aggregate of cartilage, whereby polysaccharides are released. Additionally, broad resonances at 0.85 ppm arising from collagen degradation products were observed upon the action of all applied proteases. However, glycine as a m arker of exhaustive collagen degradation was only ob­ served, if cartilage was digested by collagenase. Using more vigorous incubation conditions, additionally high-abundant amino acids of collagen (proline, hydroxyproline) could be de­ tected in the 13C-NMR-and the MALDI spectra. The observed differences are correlated with the different selectivities of the applied enzymes. It is concluded that NMR allows the detection of characteristic protein and polysaccharide degradation products. The observed differences may be of some relevance for the diagnosis of rheumatic diseases.
Water Permeability of Hypodermis Isolated from Clivia miniata Roots
Authors: Casado Carolina G. , Heredia Antonio
Published: August 2018

The fine structure and water permeability of hypoder­mis isolated from roots of Clivia miniata have been studied. The hypodermis is composed of five layers of cells arranged in radial rows. The cell walls of these lay­ers consist of primary and tertiary walls and suberized secondary walls which are lamellated. Water perm eabil­ity of the isolates was low, around the value of 10-9 m s-1. This value was found independent of the pH solu­tion and of the ionic exchange capacity of the isolates. Suberin extraction increased water permeability one or­ der of magnitude.
Inhibition of UDP-glucuronosyltransferase by 5'-O-amino Acid and Oligopeptide Derivatives of Uridine: Structure-Activity Relationships
Authors: Naydenova Zlatina G. , Grancharov Konstantin C. , Alargov Dimitar K. , Golovinsky Evgeny V. , Stanoeva Ivanka M. , Shalamanova Liliana D. , Pajeva Ilza K.
Published: August 2018

The inhibitory effect of a series of 5′-O-amino acid and oligopeptide derivatives of uridine on rat liver UDP-glucuronosyltransferase (UGT) activities was investigated using two assay systems. A quantitative structure-activity relationship (QSAR) study was performed. The compounds include a lipophilic residue linked to the nucleoside by a variable spacer. More­ over, half of the derivatives have two spacers linked to the uridine moiety. Compound 1, a serine derivative of isopropylideneuridine, was found to be the most potent inhibitor of both 4-nitrophenol (4-NP) and phenolphthalein (PPh) glucuronidation, with an I50 of 0.45 mᴍ and 0.22 mᴍ , respectively. Kinetic studies with this substance revealed a mixed type of inhibition towards 4-NP and UDP-glucuronic acid, with apparent Ki values of 150 μᴍ and 120 μᴍ , respectively. The dipeptide derivatives 11-14 exhibited a low activity against 4-NP conjuga­ tion. However, a marked suppression of PPh glucuronidation was found with compounds 11 and 13. Generally, compounds with two spacers are more inhibitory against the UGT activi­ties studied. The QSAR analysis outlined the significance of the spacers with a minimum length of 5 atoms and lipophilic residues linked to them for the inhibitory effect of the compounds. The most significant contribution to this effect is given by the six-atom spacer for both, 4-NP and PPh substrates. 4-NP converting UGT isoforms seem to respond more specifically to the inhibitors: a five-atom for the first and a six-atom for the second spacer enhance binding to both 4-NP and PPh conjugating isoenzymes, while a long second spacer contributes to inhibitor binding to UGT isoforms only converting PPh.
The Effect of Prostaglandin E1 on in vitro Transcription of Sperm Chromatin, Isolated from Patients with Azoospermia, Teratospermia and Chronic Prostatitis
Authors: Pironcheva Ganka , Miteva Kremena , Russev George Ch. , Vaisberg Chaika , Zlatarev Stoyan
Published: August 2018

We have investigated the influence of Prostaglandin E1 on the in vitro transcription of chromatin, isolated from spermatozoa of patients suffering from different pathologies, leading to infertility, namely, azoospermia, teratospermia and chronic prostatitis. Our studies indicate that prostaglandin E, has a stimulatory effect both on in vitro transcription, on the number of RNA polymerase molecules and the polyribonucleotide elongation rates as compared to sperm chromatin from healthy patients. Tlie results on the incorporation of α-32P-ATP in to RNA in the presence and absence of Prostaglandin E1 correlate well with the data on the number of actively transcribing RNA polymerase molecules and the rate of RNA elongation, which might be due to low levels of prostaglandin E1 in human semen.
Comparing Properties of Brains and Computers
Authors: Stieve Hennig
Published: August 2018

The criterion that pure natural science can only investigate objective phenomena which can be observed by independent observers sets certain limits to pure natural scientific under­ standing of brain functions. It excludes consciousness and feelings since these are only sub­ jectively accessible and alternatives cannot be decided objectively. The limitations of brain research are discussed by comparing the properties of brains and computers. At least for the time being we do not know of any natural scientific -i.e. physical or chemical -method which allows the objective measurement of consciousness, sensations, and emotions.

In addition it is discussed how and in how far our brain understands its surrounding nature.
Active Sensing -Closing Multiple Loops
Authors: König Peter , Luksch Harald
Published: August 2018

In this contribution, it is argued that the prevailing view of the sensory system as an intricate, but passive processor of external information does not capture the full complexity of brain performance. Instead, we try to reinforce a notion that sees the brain as a system embedded within the environment and actively exploring it. We will attempt to emphasize the bidirectional interaction between brain and environment at all levels of processing and at different scales of the system description. This modified approach to the understanding of the brain has profound consequences for experimental investigations, starting with the experimental design and extending into data analysis and interpretation.
Accumulation of Caffeoyl-D-quinic Acids and Catechins in Plums Affected by the Fungus Taphrina pruni
Authors: Fuchs Claus T. , Spiteller Gerhard
Published: August 2018

Plums (Prunus domestica) affected by the fungus Taphrina pruni and healthy ones were harvested in intervals of about four days. Photometric comparison of their methanolic extracts proved that infected fruits contained ten times more compounds with phenolic hydroxyl groups. Further structure elucidation and quantification of these phenolic differences by gas chromatography and gas chromatography / mass spectrometry revealed that the content of caffeoyl-ᴅ-quinic acid isomers and (+)-catechin had changed: The amount of chlorogenic acid and its isomers was increased in infected fruits about 15 times compared to nonaffected ones. Contrary, (+)-catechin content was decreased. Additional photometric assays demonstrated that (+)-catechin reduction is accompanied by a corresponding increase of proanthocyanidins in infected fruits. All the compounds identified in infected plums in increased concentrations had a common structural feature: they were o-diphenols. After oxidation to corresponding o-quinones they are able to add to substances with active hydrogen atoms, e.g. fungal enzymes. Consequently, the accumulation of a high concentration of odiphenols may be a defence response directed towards fungal enzymes.
Complete Sequence of Glycolytic Enzymes in the Mycorrhizal Basidiomycete, Suillus bovinus
Authors: Kowallik Wolfgang , Thiemann Meinolf , Huang Yi , Mutumba Gerard , Beermann Lisa , Broer Dagmar , Grotjohann Norbert
Published: August 2018

Axenic cultures of Suillus bovinus were cultivated in inorganic liquid medium with glucose as a carbon source at 25 °C and continuous supply of oxygen by aeration with compressed air in the dark. Exogenous fructose as sole carbon source yielded about 50% less increase in dry weight than glucose. This resulted from different uptake velocities. Sucrose as sole exogenous carbon source yielded no measurable increase in dry weight.

In glucose cultures, activities of all glycolytic enzymes were found. Maximum specific activities varied largely (from about 60 [fructose 6-phosphate kinase] to about 20 000 [triosephosphate isomerase] nmoles · mg protein-1 · min-1). Apparent Km-values also varied over more than two orders of magnitude (0.035 mᴍ [pyruvate kinase] to 6.16 mᴍ [triosephosphate isomerase]). Fructose 6-phosphate kinase proved to be the fructose 2,6-bisphosphate-regulated type, aldolase the divalent cation-dependent (class II) type and glyceratephosphate mutase the glycerate 2,3-phosphate-independent type of the respective enzymes. Eight of the 10 enzymes exhibited pʜ-optima′ between 7.5-8.0. Triosephosphate isomerase and pyruvate kinase showed highest activities at pʜ 6.5. Regulatory sites within the glycolytic pathway of Suillus bovinus are discussed; fructose 6-phosphate kinase appears to be its main bottle neck.
The Electrophoretic Separation of Curved Cisplatin-Modifled DNA Fragments on Polyacrylamide Gels Is Dependent on the Voltage Gradient
Authors: Yaneva Julia , Zlatanova Jordanka
Published: August 2018

Polyacrylamide gel electrophoresis has been widely used to study DNA fragments containing sequence-dependent curvature. The anomalous electrophoretic behavior of curved DNA fragments on such gels allows their separation from straight fragments of the same length. Here we demonstrate that polyacrylamide gels can be successfully used to resolve DNA fragments modified at a single site by the antitumor drug cis-diamminedichloroplatinum(II) (cis-DDP, cisplatin) from their unmodified counterparts. However, the resolution strongly depends on the voltage gradient, being completely lost when it drops below a certain threshold level. The param eters of the electric field do not affect separation of ‘normal’ DNA fragments of comparable length.
A New Pyoverdin from Pseudomonas aureofaciens
Authors: Beiderbeck H. , Risse D. , Budzikiewicz H. , Taraz K.
Published: August 2018

From Pseudomonas aureofaciens a new pyoverdin was isolated and its structure was determined by various spectroscopic methods and by partial degradation
Transformation of Aminosteroids into Pharmacologically Active Amides of Phenolic Acids
Authors: Todorova Daniela , Tupova Maria , Zapreva Veneta , Milkova Tsenka , Kujumdjiev Atanas
Published: August 2018

Amides of cinnamic acid derivatives with 3α-and 3β-cholestanylamines, as well as with 3α-and 3β-amino-(2’-aminoethyl)-cholest-5-en were synthesized using dicyclohexylcarbodiimide (DCC) and 1-hydroxy-benzotriazole as efficient additives. Their structure was determined by UV and 1HNMR . 3β-Amino-(2’-aminoethyl)-cholest-5-en, amides of p-hydroxy-cinnamic acid 4 and 9, and N-cholest-5-en-3α-aminoethyl-di-(3’’,-phenyl-trans-2’’-propene)-amide 10 showed moderate antibacterial activity against Staphylococcus aureus
Identification and Cloning of a Gene Locus Encoding Peptide Synthetase of Pseudomonas fluorescens by Two Sets of PCR Primers
Authors: Rajendran Narayanan
Published: August 2018

A chromosomal locus encoding biosynthetic genes for a putative peptide synthetase of Pseudomonas fluorescens was identified and cloned. To achieve this, two sets of degenerated oligonucleotide primers KAGGA:SGTTG and TGD :LGG were used in PCR. These primers were selected based on highly conserved units of known peptide synthetases involved in adenylation and thiolation regions of Bacillus subtilis. The discrete amplified bands from PCR ca. 300 bp for KAGGA:SGTTG and ca. 500 bp for TGD:LGG proved to be integral part of the genomic DNA of P. fluorescens were cloned and sequenced. Sequence alignments of both fragments confirmed the putative peptide synthetase genes in P. fluorescens. The present study describes the identification and cloning of peptide synthetase genes of P. fluorescens, which can be used to identify a genetic locus encoding peptide synthetase in other microbial species
An Incremental Hebbian Learning Model of the Primary Visual Cortex with Lateral Plasticity and Real Input Patterns
Authors: Burger Thomas , Lang Elmar W.
Published: August 2018

We present a simplified binocular neural network model of the primary visual cortex with separate ON/OFF-pathways and modifiable afferent as well as intracortical synaptic couplings. Random as well as natural image stimuli drive the weight adaptation which follows Hebbian learning rules stabilized with constant norm and constant sum constraints. The simulations consider the development of orientation and ocular dominance maps under different conditions concerning stimulus patterns and lateral couplings. With random input patterns realistic orientation maps with ± 1/2-vortices mostly develop and plastic lateral couplings self-organize into mexican hat type structures on average. Using natural greyscale images as input patterns, realistic orientation maps develop as well and the lateral coupling profiles of the cortical neurons represent the two point correlations of the input image used
Arcapitins A - C, First Dammarane-Type Triterpenes from the Convolvulaceae§
Authors: Tofern Britta , Jenett-Siems Kristina , Siems Karsten , Jakupovic Jasmin , Eich Eckart
Published: August 2018

Three new dammarane-type triterpenes, named arcapitin A, B and C, were isolated from the roots of Argyreia capitata (Convolvulaceae). They turned out to be 11α-acetoxydammar-24-ene-20(S)-ol-3-one, damm ar-24-ene-11a,20(S)-diol-3-one and 11a-acetoxydammar-24- ene-3β,20(S)-diol. While the same compounds were also detected in the aerial vegetative parts of this species, their occurrence in a number of other convolvulaceous species could not be confirmed.
Scaling of Some Metabolic Enzymes in Liver of a Freshwater Teleost: An Adaptive Mechanism
Authors: Tripathi Ghanashyam
Published: August 2018

The activities of mitochondrial malate dehydrogenase (mMDH ) and the total mitochondrial proteins increase as a function of body mass in the freshwater catfish, Clarias batrachus. It clearly indicates an increase in energy production in larger- sized individuals for various purposes including prey-predator interactions. The higher activity of lactate dehydrogenase (LDH) in larger fish may indicate more production of lactate for gluconeogenesis in the liver to meet emergency requirements of increased energy demand. However, the activity of cytoplasmic malate dehydrogenase (cMDH) decreases with the increasing body mass of the fish which reflects reduction in NADPH production and, in turn, reduced lipogenesis in liver of larger individuals. Thus, the present observations suggest an adaptive mechanism dealing with the higher energy budget, and reduced synthetic activities (lipogenesis) in the liver of larger-sized freshwater catfish. This type of biochemical scaling might be also supporting other metabolic pathways in order to adjust some physiological functions for survival in the aquatic environment.
The Non-Mevalonate Isoprenoid Biosynthesis of Plants as a Test System for New Herbicides and Drugs against Pathogenic Bacteria and the Malaria Parasite
Authors: Lichtenthaler Hartmut K. , Zeidler Johannes , Schwender Jörg , Müller Christian
Published: August 2018

Higher plants and several photosynthetic algae contain the plastidic 1-deoxy-ᴅ-xylulose 5- phosphate / 2-C-methyl-ᴅ-erythritol 4-phosphate pathway (DOXP/MEP pathway) for isoprenoid biosynthesis. The first four enzymes and their genes are known of this novel pathway. All of the ca. 10 enzymes of this isoprenoid pathway are potential targets for new classes of herbicides. Since the DOXP/MEP pathway also occurs in several pathogenic bacteria, such as Mycobacterium tuberculosis, and in the malaria parasite Plasmodium falciparum, all inhibitors and potential herbicides of the DOXP/MEP pathway in plants are also potential drugs against pathogenic bacteria and the malaria parasite. Plants with their easily to handle DOXP/MEP-pathway are thus very suitable test-systems also for new drugs against pathogenic bacteria and the malaria parasite as no particular security measures are required. In fact, the antibiotic herbicide fosmidomycin specifically inhibited not only the DOXP reductoisomerase in plants, but also that in bacteria and in the parasite P. falciparum, and cures malaria-infected mice. This is the first successful application of a herbicide of the novel isoprenoid pathway as a possible drug against malaria.
β-1,3-Glucooligosaccharide Induced Activation of Four Enzymes Responsible for N-p-coumaroyloctopamine Biosynthesis in Potato (Solanum tuberosum cv.) Tuber Tissue
Authors: Matsuda Fumio , Miyagawa Hisashi , Ueno Tamio
Published: August 2018

Potato tuber disks, when treated with laminarin, a β-1,3-glucooligosaccharide from Laminaria digitata, accumulate a hydroxycinnamoyl amide compound, N-p-coumaroyloctopamine (p-CO). The biosynthesis of p -CO was investigated by feeding experiments, in order to show that the precursors of N-p-coumaroyl and octopamine moieties of p-CO are ʟ-phenylalanine and ʟ-tyrosine, respectively. The treatment of potato tuber tissue with laminarin resulted in elevated activities of four enzymes which are putatively involved in p-CO biosynthesis: phenylalanine ammonia lyase (PAL; EC 4.3.1.5), 4-hydroxycinnamic acid:CoA ligase (4CL; EC 6.2.1.12), hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase (THT; EC 2.3.1.110) and tyrosine decarboxylase (TyrDC; EC 4.1.1.25). Among these, the response of TyrDC was specific to laminarin treatment, thus indicating that the regulation of TyrDC activity is critical for the accumulation of p -CO in potato tuber tissue.
Tricarboxylic Acid Cycle Enzymes of the Ectomycorrhizal Basidiomycete, Suillus bovinus
Authors: Grotjohann Norbert , Huangb Yi , Kowallik Wolfgang
Published: August 2018

In crude cell extracts of the ectomycorrhizal fungus, Suillus bovinus, activities of citrate synthase, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarase, and malate dehydrogenase have been proved and analyzed. Citrate synthase exhibited high affinities for both its substrates: oxaloacetate (Km = 0.018 mᴍ) and acetyl-CoA (Km = 0.014 mᴍ) . Aconitase showed better affinity for isocitrate (Km = 0.62 mᴍ) than for citrate (Km = 3.20 mᴍ) . Analysis of isocitrate dehydrogenase revealed only small maximum activity (60 nmol x mg protein-1 x min -1), the enzyme being exclusively NADP+-dependent. Using the artificial electron acceptor dichlorophenol indophenol, activity and substrate affinity of succinate dehydrogenase were rather poor. Fumarase proved Fe2+-independent. Its affinity for malate was found higher ( Km = 1.19 mᴍ) than that for fumarate ( Km = 2.09 mᴍ) . High total activity of malate dehydrogenase could be separated by native PAGE into a slowly running species of (mainly) cytosolic (about 80%) and a faster running species of (mainly) mitochondrial origin. Affinities for oxaloacetate of the two enzyme species were found identical within limits of significance (Km = 0.24 mᴍ and 0.22 mᴍ) . The assumed cytosolic enzyme exhibited affinity for malate (Km = 5.77 mᴍ) more than one order of magnitude lower than that for oxaloacetate. FPLC on superose 12 revealed only one activity band at a molecular mass of 100 ± 15 kDa. Activities of 2-oxoglutarate dehydrogenase and of succinyl-CoA synthetase could not be found. Technical problems in their detection, but also existence of an incomplete tricarboxylic acid cycle are considered. Metabolite affinities, maximum activities and pʜ-dependences of fumarase and of malate dehydrogenase allow the assumption of a reductive instead of oxidative function of these enzymes in vivo.
Self-Organization of Local Cortical Circuits and Cortical Orientation Maps: A Nonlinear Hebbian Model of the Visual Cortex with Adaptive Lateral Couplings
Authors: Burger Thomas , Lang Wolfgang
Published: August 2018

A nonlinear, recurrent neural network model of the visual cortex is presented. Orientation maps emerge from adaptable afferent as well as plastic local intracortical circuits driven by random input stimuli. Lateral coupling structures self-organize into DOG profiles under the influence of pronounced emerging cortical activity blobs. The model’s simplified architecture and features are modeled to largely mimik neurobiological findings.
Thermophysical Properties of Gaseous H2S–N2 Mixtures from First-Principles Calculations
Authors: Hellmann Robert
Published: August 2018

The cross second virial coefficient and three dilute gas transport properties (shear viscosity, thermal conductivity, and binary diffusion coefficient) of mixtures of hydrogen sulfide (H2S) and nitrogen (N2) were determined with high accuracy at temperatures up to 1200 K using statistical thermodynamics and the kinetic theory of molecular gases, respectively. The required intermolecular potential energy surface (PES) for the H2S–N2 interaction is presented in this work, while the H2S–H2S and N2–N2 PESs were reported previously. All three PESs are based on high-level quantum-chemical ab initio (i.e. first-principles) calculations. There is only very limited experimental information available on the second virial coefficients of H2S–N2 mixtures, and there appear to be no experimental data at all for the transport properties. Thus, the present predictions constitute a substantial increase in our knowledge of the thermophysical properties of this system, which are of practical relevance for modeling sour natural gas.
Los primeros años del obispado de León y la influencia de la escolástica
Authors: Sánchez Rangel Oscar
Published: August 2018

El objetivo de este trabajo consiste en explicar algunos rasgos fundamentales que caracterizaron la labor de José de Jesús Díez de Sollano y Dávalos como primer obispo de la diócesis de León, Guanajuato, fundada en 1863. Se destacará que el obispo se concentró en la revitalización de la vida parroquial y en la organización del Seminario Conciliar del obispado de León, que se convirtió en un centro muy activo para la difusión de la escolástica. Esto último se debía a que Díez de Sollano fue un protagonista del proceso de renovación que tuvo la filosofía de Tomás de Aquino en México en el siglo XIX, que se conoció como neotomismo. Más tarde, el seminario y la curia de León rechazaron y obstaculizaron la enseñanza del positivismo en esa ciudad, por lo que el trabajo contribuye a reflexionar acerca de las variaciones locales que tuvo su expansión en México.
La memoria como configuración de mundo en El reino de Celama, de Luis Mateo Díez
Authors: Sánchez Pineda Ernesto
Published: August 2018

En el presente trabajo, se hace un acercamiento a la novela de Luis Mateo Díez, El reino de Celama, para ver el papel que tiene la memoria en su configuración. Para ello, las tres novelas de las que se compone El reino… (El espíritu del páramo, La ruina del cielo y El Oscurecer) se analizan tomando en cuenta la presencia constante de la literatura oral en la escritura, la fragmentación del relato, el recuerdo y, obviamente, la memoria. Las teorías de otros investigadores, así como las propias reflexiones metaliterarias y literarias de Mateo Díez, permiten ir asentando el funcionamiento de la memoria en esta novela. Con la misma intención, hay aproximaciones a otras obras que se configuran de manera similar, pues el espejeo de espacios, funciones, personajes, también arroja luz al concepto que aquí se analiza como configurador de mundo.
La prensa habanera: refugio de los intelectuales desterrados durante la Revolución Mexicana, 1910-1920
Authors: García Rodríguez Salvador
Published: August 2018

Resumen: el presente trabajo tiene como principal objetivo bosquejar la labor de los intelectuales desterrados durante la Revolución Mexicana en las revistas culturales y los periódicos cubanos más representativos de la segunda década del siglo XX. Se trata de un tema apenas analizado en los estudios históricos y siempre desde su aspecto político. Basado en el rescate de textos hasta la fecha desconocidos, se reconstruye el itinerario de los escritores nacionales en los medios habaneros durante los momentos más álgidos de la lucha armada. En un primero apartado, el trabajo ofrece un panorama general de los exiliados en Cuba, para posteriormente enfocarse en las figuras de Federico Gamboa y Luis G. Urbina.
The Art of Referencing as an Often Overlooked Aspect of Scientific Literacy: Study of a Classroom Intervention
Authors: Rehorek Susan J. , Dafoe Nicole J.
Published: August 2018

Scientific literacy is a complex topic that is often cited, but rarely fully defined. Teaching scientific literacy often focuses solely on scientific reading and writing. However, to be scientifically literate, one must also be able to distinguish between credible and non-credible sources of information. Such ability involves a thorough knowledge of referencing and the peer-review process. To incorporate such issues into the teaching of a specific aspect of scientific literacy, a two-part module was developed with one module focusing on each of the aforementioned topics. Pre-tests and post-tests assessed the efficacy of within-module assignments in terms of increasing student knowledge and confidence in understanding scientific literacy. Following completion of the modules, students were involved in a project that required the writing a scientific paper. Statistically significant gains were observed in student confidence after student completion of the module-specific assignments. Similar findings occurred in knowledge of basic formatting and peer-review after completion of the written paper. The timing in which gains occurred suggests that procedural learning occurred prior to declarative learning. Thus, a multistep process appears effective in explaining a complex topic such as scientific literacy to undergraduate students.
Fasting decreases plasma FGF21 in obese subjects and the expression of FGF21 receptors in adipose tissue in both lean and obese subjects
Authors: Nygaard Eva B , Ørskov Cathrine , Almdal Thomas , Vestergaard Henrik , Andersen Birgitte
Published: August 2018

Fibroblast growth factor 21 (FGF21) is a metabolic regulator of energy and lipid metabolism. FGF21 is highly expressed in liver while FGF21 receptors (beta-klotho (KLB) and FGFR1c) are highly expressed in white adipose tissues (WATs). Plasma FGF21 has been shown to be increased after 7–10 days of fasting but oppositely plasma FGF21 is also increased in obesity. The aim of this study was to measure the effect of 60 h of fasting on plasma FGF21 levels in obese and lean subjects and to determine the gene expression ofKLBandFGFR1cin the subcutaneous WAT before, during and after 60 h of fasting. Eight obese (BMI >30 kg/m2) and seven lean subjects (BMI <25 kg/m2) were fasted for 60 h and blood samples were taken at time 0 and after 12, 36 and 60 h of fasting. A biopsy from the subcutaneous WAT was taken at time 0, 12 and 60 h of fasting. FGF21 was measured in plasma by an ELISA and mRNA expression ofKLBandFGFR1cwas measured in WAT by quantitative PCR (qPCR). The fast significantly decreased plasma FGF21 in obese subjects while no change in plasma FGF21 was observed in lean subjects. Interestingly,KLBwas significantly decreased in WAT in response to fasting in both lean and obese subjects indicating a potential important adaptive regulation ofKLBin response to fasting.