Stereospecificity and electrogenicity of amino acid transport in Riccia fluitans

In the aquatic liverwort Riccia fluitans, membrane depolarization (_m), change in membrane conductance (g_m), and current-voltage (I-V) characteristics in the presence of different amino acids as well as the uptake of ¹⁴C-labeled amino acids were measured. L-isomers of the tested amino acids generate larger electrical effects (_m, g_m) than D-isomers, and the I-V characteristics show that the positive electrical inward-current of 20 mA m^-2 generated by 0.5 mM D-serine is only about 50% of the current generated by adding 0.5 mM L-serine. Whereas - and -amino acids rapidly depolarize the membrane to the same extend, with -aminobutyric acid (-AB) and dipeptides no significant electrical effects have been measured. The uptake kinetics of ¹⁴C-labeled amino acids display three components: (I) A saturable high-affinity component with K_s-values of 48 M D-alanine, 12 M -aminoisobutyric acid (AIB), 9 M L-alanine, 8 M L-proline, and 6 M L-serine, respectively; (2) an apparently linear low-affinity component, and (3) an also linear but unspecific component at concentrations >20 times the given K_s-value. Uptake of ¹⁴C-labeled AIB can be inhibited competitively by all tested neutral amino acids, the L-isomers being more effective than the D-isomers, as well as by ammonium or methylamine. Vice versa, AIB competitively inhibits uptake of L-serine and L-alanine. It is concluded that an uncharged stereospecific carrier for the investigated amino acids exists in the plasmalemma of Riccia fluitans. Accumulation ratios of about 50 suggest secondary active transport driven by a transmembrane electro-chemical gradient (mainly _m) which is generated by the electrogenic proton pump. It is suggested that this carrier binds to the amino group forming either a charged binary complex with positively charged amines (Felle 1980), or an uncharged complex with -AB or dipeptides, whereas electrogenic transport of - and -amino acids is mediated by a ternary carrier complex, probably charged by a proton.Symbols and Abbreviations _m membrane potential (mV) - E_co equilibrium potential (mV) of the transport system - g_m membrane (slope) conductance (Sm^-2) - g_m change in g_m - I-V curve current-voltage curve - AIB -aminoisobutytric acid - -AB -aminobutyric acid     

Receptor‐Ck regulates giardia encystation process

The study addressed to resolve the mechanism involved in cholesteroldependent regulation of giardia encystation process, revealed that (a) the trophozoites have the ability to express genes coding for receptorC_k and sterol element binding protein (SREBP); (b) inhibition of cholesterol dependent activation of receptorC_k results in the upregulation of CWP1 gene expression leading to encystation process. Based upon these findings, we propose that receptorC_k dependent signalling is responsible for the regulation of giardia encystation process by cholesterol.     

Ortstreue, Altersaufbau und Mortalit?t einer Population des Baumpiepers(Anthus t. trivialis)

Zusammenfassung 1. Von den in einer intensiv untersuchten Population des Baumpiepers in Nordbelgien beringten Nestlingen kehrten 24 junge und 3 junge zurück. 12 von 17 farbberingten Jungvögeln stammten dabei aus Erstbruten.2. 6 und die beiden waren Heimatansiedler, 1 Fremdansiedler, 6 geburtsortstreu und 2 Geburtsorts-Rücksiedler.3. Die mittlere Entfernung des Revieres vom Geburtsnest betrug bei den geburtsortstreuen 184±118 m, bei den anderen 818±368 m.4. Alte zeigen größere Umsiedlungsentfernungen als alte .5. Einjährige haben in der Population einen sehr hohen Anteil.6. 79 % der und 50 % der kehrten wieder in die Population zurück.7. Die Population umfaßte durchschnittlich 42 Brutpaare. Der Anteil an ledigen Altvögeln betrug 7 %. Die Siedlungsdichte erreichte einen Wert von 3,6 Brutpaaren pro 10 ha (ohne Gewässer).8. Angaben zu Paartreue, Paarauflösung, Bigynie und Paarbildung werden mitgeteilt.9. Aus den Rückkehrzahlen errechnet sich eine durchschnittliche Mortalität der jungen von etwa 65 %, eine Lebenserwartung von einem Jahr und ein Durchschnittsalter von 1,5 Jahren.10. 2,5 % der gelegten Eier bzw. 4,6 % der ausgeflogenen Jungvögel erbrachten brutreife Rückkehrer.11. Für alte errechnet sich eine Mortalität von 47,5 %, für alte von 66,7 % und eine Lebenserwartung von 1,6 bzw. 1,0 Jahren.12. Zum Erhalt der Population müssen jährlich etwa 46 % der ausgeflogenen Jungvögel bis zum nächsten Jahr überleben.13. Die untersuchte Population ist durchschnittlich aus 4,6 % geburtsortstreuen Jungvögeln, 41,3 % fremden Jungvögeln, 37,4 % ortstreuen Altvögeln und 16,7 % unbekannter Altvögel zusammengesetzt.

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Site-tenacity, age structure and mortality in a population of the tree pipit(Anthus t. trivialis) in northern Belgium

Summary 1. 24 first year and 3 first year , ringed as nestlings, returned in next years. 12 of 17 colour-ringed birds came from first broods.2. 6 and the 2 were Heimatansiedler, 1 Fremdansiedler, 6 geburtsortstreu and 2 Geburtsorts-Rücksiedler.3. The mean distances between the first territory and the birth nest of the geburtsortstreue and of the other were 818±368 m and 184±118 m respectively.4. Adult showed greater settling distances than adult .5. The percentage of first year was very high.6. 79 % and 50 % returned to their breeding population in next years.7. The mean density of the population was 42 pairs or 3,6 pro 10 ha. Unpaired adults amounted 7 %.8. Data on pair formation, mate-faithfulness and bigyny are treated.9. Calculation of mortality from the data of returned birds yielded a mortality of young of 65 %, a life expectancy of one year and a mean life time of 1,5 years.10. Sexual mature individuals derived from 2,5 % of all eggs laid and from 4,6 % of all youngs fledged.11. The computed mortality of adult is 47,5 % and of adult 66,7 %. The life expectancy is 1,6 and 1,0 years for adult and respectively.12. Allowing for the annual losses of adults a survival rate of first year birds of about 46 % is necessary.13. The mean annual composition of the population should be: 4,6 % geburtsortstreue juveniles, 41,3 % non-autochthonous juveniles, 37,4 % ortstreue adults and 16,7 % unknown adults.

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Mit Unterstützung des Nat. Fonds v. Wetenschappelijk Onderzcek, Brüssel.     

Simultaneous measurement of biogenic amines and their metabolites in rat brain regions after acute administration of and abrupt withdrawal from butorphanol or morphine

Changes in levels of biogenic amines and metabolites were measured using high performance liquid chromatography fitted with an electrochemical detection in various rat brain regions after acute administration of and abrupt withdrawal from continuous intracerebroventricular infusion of butorphanol (a // mixed opioid receptor agonist) or morphine (a -opioid receptor agonist). A single dose of butorphanol (26 nmol/5 l) or morphine (26 nmol/5 l) increased levels of 3,4-dihydroxyphenylacetic acid in the striatum and limbic region and of homovanilic acid in the cortex, striatum, and limbic region. In animals which had been infused with butorphanol (26 nmol/l/hr) or morphine (26 nmol/l/hr) for 3 days, an increase in dopamine turnover was observed. The levels of 3,4-dihydroxyphenylacetic acid was decreased and that of homovanilic acid was increased in the striatum, limbic region, and midbrain immediately after termination of opioid infusion. Both dopamine metabolites (in these areas) were decreased at 2 and 6 hr after butorphanol or morphine withdrawal. Changes in norepinephrine, serotonin, and 5-hydroxyindoleacetic acid levels in some brain regions were observed in the morphine-, but not in butorphanol-dependent rats. These data suggest that the increase and the decrease in dopaminergic activity, but not noradrenergic and serotonergic neurons, in the some brain regions are closely associated with the production of antinociception of and the expression of withdrawal syndrome from butorphanol and morphine, respectively.     

Secondary structure of the entomocidal toxin from Bacillus thuringiensis subsp. kurstaki HD-73

The secondary structure of the toxin fromBacillus thuringiensis subsp.kurstaki (Btk) HD-73 was estimated by Raman, infrared, and circular dichroism spectroscopy, and by predictive methods. Circular dichroism and infrared spectroscopy gave an estimate of 33–40% -helix, whereas Raman and predictive methods gave approximately 20%. Raman and circular dichroism spectra, as well as predictive methods, indicated that the toxin contains 32–40% -sheet structure, whereas infrared spectroscopy gave a slightly lower estimate. Thus, all of these approaches are in agreement that the native conformation of Btk HD-73 toxin is highly folded and contains considerable amounts of both -helical and -sheet structures. No significant differences were detected in the secondary structure of the toxin either in solution or as a hydrated pellet.     

The glycolipid specificity ofErythrina cristagalli agglutinin

The interaction of¹²⁵I-labeledErythrina cristagalli agglutinin (ECA) with neutral glycosphingolipids on thin layer chromatograms was examined by the overlay technique followed by radioautography. The lectin bound topara-globoside with a sensitivity about 10 times higher than to lactosylceramide or globoside, in agreement with the specificity of the lectin forN-acetyllactosamine. The lower limit of detection ofpara-globoside was about 0.66 nmol. The specific binding of ECA to this glycolipid was confirmed by a highly sensitive enzyme-linked lectin assay (ELLA), utilizing the horseradish peroxidase-avidin-biotin system for detection of bound lectin. Overlays of neutral glycosphingolipid extracts from human erythrocyte membranes and from human granulocytes with ECA demonstrated that the lectin can be employed for the detection of small amounts ofpara-globoside in biological materials also in the presence of excess globoside. No staining was obtained when thin layer chromatograms of neutral glycosphingolipid extracts from rabbit erythrocyte membranes were overlayed with¹²⁵I-ECA. Afterin situ treatment of the chromatograms with -galactosidase, the lectin bound to several components, one of which had a mobility corresponding to that of the pentahexosylceramide Gal3Gal4GlcNAc3Gal4Glc1Cer, the major neutral glycosphingolipid of rabbit erythrocytes, thus providing further evidence for the specificity of ECA forpara-globoside.Abbreviations GSL glycosphingolipid(s) - CDH lactosylceramide, Gal4Glc1Cer - CTH trihexosylceramide, Gal4Gal4Glc1Cer - GLOB globoside, GalNac3Gal4Gal4Glc1Cer - PG para-globoside, Gal4GlcNAc3Gal4Glc1Cer - AsG_M1 asialo-G_M1, Gal3GalNAc4Gal4Glc1Cer - FORS Forsmann antigen, GalNAc3GalNAc3Gal4Gal4Glc1Cer - CPH pentahexosylceramide, Gal3Gal4GlcNAc3Gal4Glc1Cer - ECA Erythrina cristagalli agglutinin - SBA soybean agglutinin - PBS phosphate-buffered saline - PVP-40 polyvinylpyrrolidone M.W. 40000 - BSA bovine serum albumin - HRP-avidin horseradish peroxidase conjugated to avidin - ELLA enzyme-linked lectin assay - ELISA enzyme-linked immunosorbent assay - PMNL polymorphonuclear leukocytes - HPTLC high performance thin layer chromatography     

Erörterungen zur definition und anwendbarkeit der begriffe “ultimate factor”, “proximate factor” und “Zeitgeber”

Summary The use of the terms, which have not always been employed uniformly throughout the literature, is discussed and an exact definition is tried. Application of the terms ultimate and proximate factors should not be restricted to annual and circadian periodicities. Instead they should be used for all temporally or spatially restricted processes for which a difference between selecting and regulating mechanisms is to be found. Ultimate factors are environmental factors which in the course of evolution have led, through natural selection, to the relevant restriction. Proximate factors may be defined as those external stimuli which initiate or maintain biological processes under most favourable ecological conditions. The term Zeitgeber finally, should only be used where endogenous circadian or circennial periodicities are synchronized with environmental changes through external factors. In this sense Zeitgeber is merely a special case of proximate factor.

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Ich danke den Herren Prof. Dr. J. Aschoff, Dr. E. Gwinner und Dr. K. Hoffmann, Erling-Andechs, und Prof. Dr. D. S. Farner, Seattle, für die kritische Durchsicht des Manuskriptes und viele wertvolle Hinweise und Anregungen.     

Study of Oligosaccharide Specificity of Perch Roe Fucolectin Using Gold-Labeled Neoglycoproteins

The specificity of perch (Perca fluviatilis) roe fucolectin was studied using the protein dot blot technique, followed by detection with colloidal gold–labeled neoglycoproteins bearing human milk oligosaccharides. The strongest binding was noted with the H type 1 pentasaccharide lacto-N-fucopentaose (Fuc1-2Gal1-3GlcNAc1-3Gal1-4Glc); the interaction with the H type 6 trisaccharide 2"-fucosyllactose (Fuc1-2Gal1-4Glc) was weaker. Binding of the perch lectin to the Lewis antigens (associated with tumors and embryonic tissues) was also studied. It was found that the lectin weakly interacted with the hexasaccharide lacto-N-difucohexaose I, Le^b (Fuc1-2Gal1-3[Fuc1-4]GlcNAc1-3Gal1-4Glc), but not with Le^a, Le^c, or Le^x antigens. Thus, the perch roe lectin exhibited pronounced differences in carbohydrate specificity from other fucolectins—a feature that may be used in structural studies and isolation of fucose-containing glycoconjugates.     

“Relatedness” between antibodies —Implications on immunogenetic systems

Summary A serologic model, a mathematical treatment of this model as well as experimental serologic evidence have all made it highly probable that a new type of relatedness between antibodies, (at least assumed to react with antigens within the same immunogenetic system) is a very common phenomenon.It is shown that conventional models assuming monospecific and unrelated base reagents give rise to erroneous assumptions regarding the serologic and genetic aspects of immunogenetic systems if the base reagents are instead related. Thus a relation between antibodies could falsely be interpreted as being instead a relation between antigens on a serologic; genetic or biochemical level.

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Zusammenfassung Die statistische Behandlung eines serologischen Modells und experimentelle serologische Ergebnisse führen zu der Annahme einer häufig vorkommenden neuartigen Beziehung zwischen Antikörpern.Voraussagen über serologische und genetische Aspekte immunogenetischer Systeme können unter der Voraussetzung der hier postulierten Beziehung deshalb zu Irrtümern führen, weil die konventionellen Modelle monospezifische und nicht miteinander in Beziehung stehende Reagentien voraussetzen.

     

A Comparative Analysis of Interhelical Polar Interactions of Various α-Helix Packings in Proteins

One hundred twenty globular proteins and forty five leucine zippers representing all types of packing of long -helices were studied in terms of revealing and comparing their interhelical hydrogen and salt bonds. Many previous studies of leucine zippers and their analogs showed that interhelical interactions between polar groups could impart specificity to packing of an -helix. The current comparison demonstrated that basically, globular proteins and leucine zippers had similar interhelical polar interactions with presumably a similar structural role. However, depending on the packing of -helices, the networks of interhelical polar bonds were shown to be distinct and determined both by physicochemical properties of involved amino acid residues and by the relative positions of hydrophobic and hydrophilic residues on the surface of -helices. The revealed distinction is probably crucial for selecting the unique packing of an -helix.     

Determination of three enzyme polymorphisms in one electrophoretic step on horizontal polyacrylamide gels

Summary A method that allows separation and determination of three enzyme polymorphisms in one polyacrylamide gel is described. Common phenotypes of adenylate kinase, adenosine deaminase and phosphoglucomutase are diagnosed without difficulties. There are small migration differences between PGM isozymes e and d.

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Zusammenfassung Es wird eine Methode beschrieben, die Trennung und Darstellung von drei Enzympolymorphismen in einem Polyacrylamid-Gel ermöglicht. Die Normtypen der Adenylatkinase, Adenosindeaminase und Phosphoglucomutase sind zweifelsfrei zu differenzieren. Geringe Wanderungsunterschiede ergeben sich zwischen den Zonen e und d der PGM Isoenzyme.

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(Direktor: Prof. Dr. W. Janssen)     

Measurement of proton relaxation rates in proteins

Summary Five different types of experiment are described which make it possible to measure various relaxation rates of selected protons in crowded spectra of macromolecules such as proteins: longitudinal spin-lattice relaxation rates =1/T₁, transverse relaxation rates =1/T₂ measured under conditions of free precession, transverse relaxation rates ¹ _LOCK=1/T₁ measured under conditions of spin-locking, and transverse relaxation rates ^DQC=1/T₂ ^DQC and ^ZQC=1/T₂ ^ZQC of double- and zero-quantum coherences. The surprisingly large discrepancy between the transverse rates ^t and ^t is discussed in detail. To separate overlapping proton signals, the experimental schemes involve one or several magnetization transfer steps, using a doubly selective homonuclear Hartmann-Hahn method. Numerous variants of the basic ideas can be conceived, depending on the extent of signal overlap and on the topology of the networks of scalar couplings. Applications are shown to H and H of Tyr²³, to H, H and H of Cys³⁰, and to H and H of Ala²⁴ in bovine pancreatic trypsin inhibitor (BPTI).     

Cloning and expression of a β-glycosidase gene from Thermus thermophilus. Sequence and biochemical characterization of the encoded enzyme

A 3.2 kilobase pair DNA fragment from Thermus thermophilus HB27 coding for a -galactosidase activity was cloned and sequenced. A gene and a truncated open reading frame orf1 encoding respectively a -glycosidase (tt-gly) and probably a sugar permease were located directly adjacent to each other. The deduced aminoacid sequence of the enzyme Tt-gly showed strong identity with those of -glycosidases belonging to the glycosyl hydrolase family 1. The enzyme was overexpressed in Escherichia coli and was purified by a two-step purification procedure. The recombinant enzyme is monomeric with a molecular mass of 49-kDa. It catalyzes the hydrolysis of -D-galactoside, -D-glucoside and -D-fucoside derivatives. However, the kcat/Km ratio is much higher for p-nitrophenyl--D-glucoside and p-nitrophenyl--D-fucoside than for p-nitrophenyl--D-galactoside. The specificity towards linkage positions of the disaccharides tested decreased in the following order: 1-3 (100%) < 1-2 (71%) < 1-4 (40%) < 1-6 (10%). Tt-gly is a thermostable enzyme displaying an optimum temperature of 88°C and a half life of 10 min at 90°C. It performs transglycosylation reactions at high temperature with a yield exceeding 63% for transfucosylation reactions. On the basis of this work, the enzyme appears to be an attractive tool in the synthesis of fucosyl adducts and fucosyl sugars.     

Triggering and predisposing factors in the “Red” decline syndrome of Norway spruce (Picea abies)

Summary Analysis of 62 mature Norway spruce (Picea abies provenance Viborg) trees growing in a Danish plantation was undertaken along with analysis of their nutrient contents (N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, B and Na), in each of the three youngest needle age classes, from branches of four exposure directions near the tree top. The aim was to investigate if one among the studied possible predisposing factors was also a triggering factor in the 1989 outbreak of the Red Norway spruce decline in Denmark. Neither nutrient imbalance or deficiency, nor excessive N-deposition or salt-stress were indicated as triggering factors in 1989. The Red syndrome, noticeable for the bright red colour of the current-year needles, was found to be an extension of the European type Novel Decline. Red syndrome is similar to previously reported phenomena of top-dying and sub top-dying, in that it had fewer needle age classes and significantly higher contents of mobile cations (and Ca) in the younger needle classes. Tree ring analysis suggested that the Red syndrome was initiated in the early 1980s, when the trees experienced adverse climatic conditions. Because of this long-term development of the Red Norway spruce decline syndrome, it is concluded that a triggering factor is of minor importance relative to the multitude of predisposing factors.     

Derivation of 13C chemical shift surfaces for the anomeric carbons of oligosaccharides and glycopeptides using ab initio methodology

The dependence between the anomeric carbon chemical shift and the glycosidic bond , dihedral angles in oligosaccharide and glycopeptide model compounds was studied by Gauge-Including Atomic Orbital (GIAO) ab initio calculations. Complete chemical shift surfaces versus and for d-Glcp-d-Glcp disaccharides with (11), (12), (13), and (14) linkages in both - and -configurations were computed using a 3-21G basis set, and scaled to reference results from calculations at the 6-311G^** level of theory. Similar surfaces were obtained for GlcNAcThr and GlcNAcSer model glycopeptides in - and -configurations, using in this case different conformations for the peptide moiety. The results obtained for both families of model compounds are discussed. We also present the determination of empirical formulas of the form ¹³C=f(,) obtained by fitting the raw ab initio data to trigonometric series expansions suitable for use in molecular mechanics and dynamics simulations. Our investigations are consistent with experimental observations and earlier calculations performed on smaller glycosidic bond models, and show the applicability of chemical shift surfaces in the study of the conformational behavior of oligosaccharides and glycopeptides.     

Anxiety disorders in Japan: A Review of The Japanese literature on Shinkeishitsu and taijinkyōfushī

As culture-bound syndromes, Japanese shinkeishitsu (constitutional neurasthenia) and taijinkyfush (anthropophobia) have received considerable attention in the Japanese literature. While these disorders are viewed as diagnostically distinct from Western psychiatric categories, recent studies by the Japanese suggest some affinity with Western social phobias, depression, and schizophrenia. The paper reviews this literature and offers suggestions for further cross-cultural research.This paper was accepted for publication prior to the compilation of Volume 13, No. 2, Neurasthenia in Asian Cultures. Consequently it does not refer to the papers in that volume, several of which are very relevant to the discussion in this paper.     

The tryptic peptide composition of the beta chains of hemoglobins A and B of the domestic cat (Felis catus)

Summary The tryptic peptides from the ^A and ^B chains of cat hemoglobins A and B have been isolated and the amino acid compositions determined. Differences between the two chains were found in two peptides,T-1 (GlySer) andT-14 (AsnSer and LysArg). The GlySer and LysArg substitutions are placed at-1 and-144 respectively from earlier work, and the third substitution, AsnSer at-139 is suggested from this work. In addition, the presence of a blocked amino terminus in ^B has been confirmed. Tentative sequences constructed by homology with known-chain structures suggest the occurrence of substitutions at _{1 1} contacts in ^A and ^B that may be functionally significant. There are at least 18 differences in amino acid composition between cat ^A and dog-chains and 22 differences between cat ^A and normal adult human-chains.     

Mitoseablaufstörungen

Zusammenfassung Die bei Fibroblasten- und Tumorzellen in vitro nach Einwirkung von -Methyl-oxy--phenyl--anisyl-propionitril (I) bzw. -Methyl--oxy--phenyl--anisylpropylamin (II) unter dem Bild der Sternmitosen beobachtete Metaphasearretierung läßt sich ganz allgemein durch eine Entwicklungsstörung der Zentralspindel bei erhaltener Funktionsfähigkeit der Chromosomenspindelfasern deuten. Herrn A. Mayer und Frau L. Döring danke ich für Hilfe bei der Herstellung der Mikrophotographien.Die Untersuchungen wurden mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft durchgeführt.     

Determination of the apparent K mfor oxygen of Beneckea natriegens using the respirograph technique

The affinity for oxygen of the marine bacterium Beneckea natriegens was mesured using the Respirograph technique of Degn and Wohlrab. Values between 0.15 and 0.25 M oxygen were obtained for the apparent K _mfor oxygen regardless of the nature of the respiratory substrate. These values are an order of magnitude lower than those previously reported for B. natriegens using the conventional closed oxygen electrode system.