@article{HoppeSebald1980, author = {Hoppe, J. and Sebald, Walter}, title = {Amino acid sequence of the proteolipid subunit of the proton-translocating ATPase complex from the thermophilic bacterium PS-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62754}, year = {1980}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{HoppeSchairerSebald1980, author = {Hoppe, J. and Schairer, H. U. and Sebald, Walter}, title = {The proteolipid of a mutant ATPase from Escherichia coli defective in H\(^+\)-conduction contains a glycine instead of the carbodiimide-reactive aspartyl residue}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62769}, year = {1980}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{HoppeSchairerSebald1980, author = {Hoppe, J. and Schairer, HU and Sebald, Walter}, title = {Identification of amino-acid substitutions in the proteolipid subunit of the ATP synthase from dicyclohexylcarbodiimide-resistant mutants of Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47374}, year = {1980}, abstract = {The amino acid sequence of the proteolipid subunit of the A TP synthase was analyzed in six mutant strains from Escherichia coli K 12, selected for their increased resistance towards the inhibitor N,N'-dicyclohexylcarbodiimide. All six inhibitor-resistant mutants were found to be altered at the same position of the proteolipid, namely at the isoleucine at residue 28. Two substitutions could be identified. In type I this residue was substituted by a valine resulting in a moderate decrease in sensitivity to dicyclohexylcarbodiimide. Type II contained a threonine residue at this position. Here a strong resistance was observed. These two amino acid substitutions did not influence functional properties of the ATPase complex. ATPase as well as A TP-dependent proton-translocating activities of mutant membranes were indistinguishable from the wild type. At elevated concentrations, dicyclohexylcarbodiimide still bound specifically to the aspartic acid at residue 61 of the mutant proteolipid as in the wild type, and thereby inhibited the activity of the ATPase complex. It is suggested that the residue 28 substituted in the resistant mutants interacts with dicyclohexylcarbodiimide during the reactions leading to the covalent attachment of the inhibitor to the aspartic acid at residue 61. This could indicate that these two residues are in close vicinity and would thus provide a first hint on the functional conformation of the proteolipid. Its polypeptide chain would have to fold back to bring together these two residues separated by a segment of 32 residues.}, subject = {Biochemie}, language = {en} } @article{SirenKarppanen1980, author = {Sir{\´e}n, Anna-Leena and Karppanen, H.}, title = {Influence of analgesic antipyretics on the central cardiovascular effects of clonidine in rats}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48640}, year = {1980}, abstract = {No abstract available}, subject = {Prostaglandine}, language = {en} } @incollection{Hommers1980, author = {Hommers, Wilfried}, title = {Information processing in children's choices among bets}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44169}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1980}, abstract = {Children's information processing of risky choice alternatives was investigated in two studies without using verbal reports. In Study 1, the ability to integrate the probabilities and the payoffs of simple bets was examined using the rating scale methodology. Children's choices among three of those simple bets were recorded also. By cross-classifying the children's choice and rating behavior it was shown that a three-stage developmental hypothesis of decision making is not sufficient. A four-stage hypothesis is proposed. In Study 2, the influence of enlarging the presented number of alternatives from two to three and the influence of the similarity of the alternatives on children's choice probabilities was examined with those bets. Children's choice behavior was probabilistic and was influenced only by enlarging the presented number of alternatives. These results suggest that a Bayesian approach, based on two probabilistic choice models, should not be applied in order to analyze children's choice behavior. The functional measurement approach is, as was demonstrated in Study 1, a powerful implement to further the understanding of the development of decision making.}, subject = {Kognitive Entwicklung / Informationsverarbeitung / Kind / Informationsintegration}, language = {en} } @article{Kreft1980, author = {Kreft, J{\"u}rgen}, title = {Reovirus-specific messenger ribonucleoprotein particles from Hela cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47028}, year = {1980}, abstract = {When reovirus-infected Hela cells are incubated at 43°C virus-specific messenger RNA is released ~rom the polysomes. It accumulates free in the cytoplasm as messenger ribonucleoprotem partIcles (mRNPs). The:e part~cles have a sedimentati~n rate of about 50S and a buoyant densIty m CsCI of 1.42 g/cm . ReovIrus mRNPs contam, beSIdes all three size classes of reovirus messenger RNA, the same spectrum of proteins found in the polysomal mRNPs from uninfected cells, plus t~o addi~ional pr?teins with molecular masses of 7000~ d and 110000 d, respectively. Electron mIcroscoPIc exammatlOn of the reovIrus mRNP fractIOn reveals specific Y-shaped structures wIth a total mean length ofO.5Ilm.}, language = {en} } @article{LutzJaggiLuethyetal.1980, author = {Lutz, Werner K. and Jaggi, W. and L{\"u}thy, J. and Sagelsdorff, P. and Schlatter, C.}, title = {In vivo covalent binding of aflatoxin B\(_1\) and aflatoxin M\(_1\) to liver DNA of rat, mouse and pig}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61097}, year = {1980}, abstract = {[\(^{14}\)C] Aflatoxin B\(_1\) (AFB\(_1\)) was isolated from cultures of Aspergillus parasiticus grown on [1-\(^{114}\)C] sodium acetate. Covalent binding of AFB1 to liver DNA of rat and mouse was determined 6-8 h afteroral administration. The effectiveness of covalent binding, expressedas DNA binding per dose in the units of a 'Covalent Binding Index' (CBI), (\(\mu\)mol aflatoxin/mol DNA nucleotides)/(mmol aflatoxin/kg animal), was found to be 10 400 for rats and 240 for mice. These CBI partly explain the different susceptibility of the two species for the incidence of hepatic tumors. The corresponding values for pig liver DN A, 24 and 48 h after oral administration, were found to be as high as 19 100 and 13 300. DNA-binding has not so far been reported for this species although it could represent an appropriate animal model for studies where a human-like gastrointestinal tract physiology is desirable. Aflatoxin M \(_1\) ( AFM\(_1\)) is a metabolite found in the milk of cows that have been fed AFB\(_1\)-contaminated diet. [\(^{14}\)C] AFM\(_1\) was also found to be produced by cultures of A. parasiticus giving a yield of about 0.3\% of the total aflatoxins. A test for covalent binding to rat liver DN A revealed a CBI of 2100 shoWing that AFM\(_1\) must also be regarded as a strong hepatocarcinogen. It is concluded that AFB\(_1\) contaminations should be avoided in dairy feed.}, subject = {Toxikologie}, language = {en} } @article{JaggiLutzLuethyetal.1980, author = {Jaggi, W. and Lutz, Werner K. and L{\"u}thy, J. and Zweifel, U. and Schlatter, C.}, title = {In vivo covalent binding of aflatoxin metabolites isolated from animal tissue to rat-liver DNA}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61101}, year = {1980}, abstract = {Ring-labelled [\(^{14}\)C)aflatoxin B\(_1\) (AFB\(_1\)), prepared by biosynthesis. or generally labelled [\(^3\)H]AFB\(_1\) was administered by oral gavage to young adult male rats. After 6 hr. the liver was removed and two fractions were isolated, namely macromolecules, which contamed about 3 \% of the initial dose of AFB\(_1\) radioactivity. and water-soluble, low-molecular aftatoxin conjugates containing about0·2\% of the administered radioactivity. These two fractions were administered orally to other rats in order to determine the potential of radioactive aftatoxin residues for covalent binding to DNA. Such binding can be used as an indicator for carcinogenic potency. Liver DNA was isolated 9-12 hr after admmistration of the aflatoxin derivatives and in no case was any radioactivity detected on the DNA. It can be deduced on the basis of the limit of detection of radioactivity on the DNA, that macromolecule bound AFB\(_1\) derivatives are at least 4000 times less active than AFB\(_1\) with respect to covalent binding to rat-liver DNA. and that the water-soluble conjugates are at least 100 times less potent than AFB, itself. It is concluded that the carcinogenic risk for humans who consume liver or meat. containing such aflatoxin residues is negligible when compared with the risk from intake of aftatoxins in other food items.}, subject = {Toxikologie}, language = {en} } @article{VivianiDaenikenSchlatteretal.1980, author = {Viviani, A. and D{\"a}niken, A. von and Schlatter, C. and Lutz, Werner K.}, title = {Effect of selected induction of microsomal and nuclear aryl hydrocarbon monooxygenase and epoxide hydrolase as well as cytoplasmic glutathione S-epoxide transferase on the covalent binding of the carcinogen benzo(a)pyrene to rat liver DNA in vivo}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61114}, year = {1980}, abstract = {Groups of four adult male rats [ZUR:SIV -Z] were pretreated with corn oil (control; 2 ml/kg/day i. p. for 3 days), trans-stilbene-oxide (SO; 200 mg/kg/day i. p. for 2 days), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 10 \(\mu\)g/kg i. p. once, 4 days before killing), phenobarbital (PB; 1 gjliter in the drinking water for 8 days), and dieldrin (20 mg/kg/day i. p. for 3 or 9 days). They received an injection of [G-\(^3\)H]benzo(a)pyrene (BaP, 31 \(\mu\)g/kg, 7.4. 10\(^9\) dpm/kg; i. v.) 16 h before killing. In the liver of each rat, five enzymatic activities and the covalent binding of BaP to DNA have been determined. The rnicrosomal aryl hydrocarbon monooxygenase activity (AHM) ranged frorn 75\% of control (SO) to 356\% (TCDD), the nuclear AHM from 63\% (SO) to 333\% (TCDD). Microsomal epoxide hydrolase activity (EH) was induced up to 238\% (PB), nuclear EH ranged from 86\% (TCDD) to 218\% (PB). A different extent of induction was observed in the two compartments. Highest induction of glutathione S-epoxide transferase activity (GST) was found with PB (202\%). The DNA binding of BaP was modulated within 79\% (dieldrin, 9 days) and 238\% of control (TCDD). An enzyme digest of control DNA was analysed by Sephadex LH-20 chromatography. Multiple linear regression analysis with all data expressedas o/o of control yielded the following equation: DNA Binding = 1.49 · Microsomal AHM- 1.07 · Nuclear AHM+ 0.33 · Microsomal EH- 0.52 · N uclear EH+ 0.11 · Cytoplasmic GST + 58.2. From this analysis it is concluded that (1) AHM located in the endoplasmic reticulum is most important in the formation of DNA-binding metabolites, (2) EH in the same compar.tment is not determinative in thls respect nor has it a protective effect, (3) both membrane-bound enzyme activities located in the nucleus may inactivate potential ultimate carcinogens, and ( 4) cytoplasmic GST probably cannot reduce DNA binding due to its subcellular localization.}, subject = {Toxikologie}, language = {en} } @article{ScheerSommervilleMueller1980, author = {Scheer, Ulrich and Sommerville, John and M{\"u}ller, Ulrike}, title = {DNA is assembled into globular supranucleosomal chromatin structures by nuclear contents of amphibian oocytes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39671}, year = {1980}, abstract = {The assembly of DNA into nucleosomal and supranucleosomal chromatin structures has been studied (i) by injection of circular DNA molecules (plasmids) into nuclei of Pleurodeles waltlii oocytes; and (ii) by in vitro incubation of plasmid molecules with the supernatant fraction from oocyte nuclei of Pleurodeles and Xenopus laevis, followed by purification of nucleoprotein structures formed with sucrose gradient centrifugation. [n both types of experiments , spread preparations of the newly assembled and transcriptionally inactive chromatin , examined by electron microscopy , show dense globular higher order (supranucleosomal) packing forms. Under partially relaxing (low salt) preparation conditions granular chromatin subunits of about 30 nm diameter can be seen either as widely spaced particles or in closely packed aggregates. The transcriptionally inactive endogenous chromatin of chromomeres of lampbrush chromosomes is arranged in similar higher order chromatin units. A correlation is found between the sizes of the DN A molecule probes used and the numbers of nucleosomes and higher order globules in the assembled chromatin structures. After prolonged dispersion in low salt buffers , these globular chromatin units unfold into chains of7-12 nucleosomes. The results support the concept that chromatin is arranged , under physiological ion concentrations as they are present in the nucleus , in supranucleosomal units of globular morphology.}, language = {en} }