Die Bedeutung der “feedback”-Hemmung der Threonin-Desaminase für die Synthese von Valin und Leucin

Zusammenfassung In Arthrobacter Stamm 23 führte die durch Mutation verursachte allosterische Unempfindlichkeit der Threonin-Desaminase zur dereprimierten Bildung der Enzyme im Isoleucin-Valin-Leucin-Biosyntheseweg. Derepression erfolgte auch, wenn Wildtypzellen in Gegenwart von -Ketobuttersäure inkubiert wurden. In beiden Fällen wurde Isoleucin überproduziert und ins Kulturmedium ausgeschieden. Wie aus Wachstumsexperimenten hervorging, verursachte der Überschuß an -Ketobuttersäure im Medium primär einen Valin- und Leucin-Mangel, der zu einer vorübergehenden Wachstumshemmung führte. Durch die dereprimierte Bildung der Enzyme im Isoleucin-Valin-Biosyntheseweg konnte die Wachstumshemmung überwunden werden.Der vorübergehende Hemmeffekt der -Ketobuttersäure ließ sich auf eine Konkurrenz der Substrate am ersten gemeinsamen Enzym im Isoleucin-Valin-Biosyntheseweg, der Acetohydroxysäure-Synthase, zurückführen. Wegen des niedrigen K _m-Wertes für -Ketobuttersäure wird dieses Substrat vom Enzym bevorzugt umgesetzt. Durch gaschromatographische Bestimmungen der Acetoin- und Acetyläthylcarbinol-Bildung in Enzymtests mit variierten Substrat-Konzentrationen konnte nachgewiesen werden, daß relativ geringe Konzentrationen an -Ketobuttersäure genügen, um die -Acetolacetat-Bildung vollständig zu unterdrücken. Diese Ergebnisse erklären die durch -Ketobuttersäure verursachte vorübergehende Wachstumshemmung bei Bakterien.

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The effect of the feedback inhibition of threonine deaminase on valine-leucine biosynthesis

In Arthrobacter strain 23 the allosteric insensitivity of threonin deaminase caused by mutation resulted in derepressed formation of the enzymes of the isoleucine-valine-leucine pathway. Derepression was also observed, when wild type cells were incubated in the presence of -oxobutyrate. In both cases isoleucine was overproduced and excreted. As growth experiments indicated the excess of -oxobutyrate in the medium caused endogenous valine and leucine deficiency and a transient inhibition of growth. Derepressed formation of the isoleucinevaline biosynthetic enzymes resulted in relief of growth inhibition.The transient inhibitory effect of -oxobutyrate has been traced back to substrate competition at the first enzyme common to the isoleucine and valine pathway, acetohydroxy acid synthase. Due to the low K _m of the enzyme for -oxobutyrate this substrate is preferentially converted. As proven by gaschromatographical measurements of acetoin and acetylethyl carbinol produced in enzyme (acetohydroxy acid synthase) assays with varied substrate concentrations, relatively low concentrations of -oxobutyrate are able to suppress the formation of -acetolactate completely. These results explain the transient inhibitory effect of -oxobutyrate on the growth of bacteria.

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Abkürzungen -KBS -Ketobuttersäure - FAD Flavin-adenin-dinucleotid - AHS Acetohydroxysäure - IPM Isopropylmalat - TPP Thiaminpyrophosphat     

Über den Einfluß von Gibberellinsäure auf Blüten-und Doldenbildung beim Hopfen (Humulus lupulus L.)

Zusammenfassung Die Behandlung der drei Hopfensorten Saazer, Hüller Anfang und Hallertauer mit Gibberellinsäure ergab eine Verminderung des 1000-Doldengewichtes, aber eine Zunahme der Dolden je Pflanze.Beim Hüller Anfang und beim Hallertauer nahm der Gehalt an Alpha-Säuren durch die Behandlung ab; bei der Saazer Sorte blieb er gleich bis auf die Dosierung 10 ppm, 2 x, wodurch eine Erhöhung eintrat.Bei der Handbonitierung der Dolden ergab sich eine Wertminderung besonders hinsichtlich Zapfenwuchs, Lupulingehalt und Feinheit des Aromas, wozu beim Hüller Anfang noch eine starke Doldenverlaubung hinzukommt.Die Entwicklungsdauer der ganzen Pflanze wird unter dem Einfluß von Gibberellinsäure in die Länge gezogen, so daß die Doldenreife verzögert wird. Aus frühen und mittelfrühen werden dadurch mittelfrühe bzw. späte Hopfensorten.Die weibliche Blüte wird in ihrer Ausbildung teilweise gehemmt; im Extremfall führt dies zu einer Unterdrückung aller Blütenorgane mit der Tendenz zur Rückführung des Blütenstandes in den ursprünglichen beblätterten Laubsproß. Die Kreuzungssorte Hüller Anfang reagierte außerdem mit der Bildung monözischer Blütenstände. Die Entstehung der Monözie wird diskutiert.Die unterschiedlichen Reaktionen auf die Gibberellinsäurebehandlung bei den einzelnen Sorten sind auf die verschiedenen Entwicklungszustände zum Zeitpunkt der Behandlung zurückzuführen.

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The influence of gibberellic acid on the flower and cone development in hop (Humulus lupulus L.)

Summary The treatment of the three hop-varieties Saazer, Hüller Anfang and Hallertauer with gibberellic acid caused a decrease of the 1000-cone weight, but an increase in cones of each plant.With Hüller Anfang and Hallertauer there was a decrease in -acid content, in the Saazer variety it remained equal, only when it was treated by the dosage 10 ppm, times two, an icrease in -acid content resulted.The organoleptic valuation of the cones showed a decrease in quality especially in respect to cone size, Jupulin content and delicacy of aroma. In the Huller Anfang variety a high percentage of cock hops resulted also.Under the influence of gibberellic acid the development of the hop plant is prolonged, so that the ripening of cones is retarded. Early and middle-early varieties thus become middle-early and late varieties.The female flower is somewhat retarded in development; in the extreme case this leeds to complete suppression of all flower parts and a tendency to reduce the female inflorescence to the original leaf shoot. Moreover, the hybrid variety Hüller Anfang formed monoecious plants. The origin of monoecious plants is discussed.The different reactions to treatment with gibberellic acid of the several varieties are caused by the differing stages of plant development at the time of treatment.

     

Genotype-environment interaction for awn development in isogenic lines of barley

Summary Awn length of four isogenic lines of barley differing by two genes for awn development (A andB) and their short iinkage blocks was evaluated at a wide range of plant densities (0.002 to 3.345 m²/plant) for two years. Awn development was reduced at high plant density. The quarter-awned genotype (aaBB) became phenotypically awnless (aabb) at high plant density. Similar results were obtained each year and the genotype x plant density effect was the major portion of the genotype-environment interaction variance. Additive ( _A , _B ) and additive x additive ( _AB ) gene effects were computed for each plant density for lateral and central floret awn length. For lateral awns _AB was not affected, but _A and _B increased with decreased plant density. In contrast, for central awns _A and _AB decreased and _B increased with decreased plant density.Central floret awns measured at each spike node showed that high plant density reduced awn development most in the lower half of the spike. This is the zone of most rapid awn differentiation and since culm elongation and spike growth rates were greatly increased by high plant density, it was suggested that rapid growth invoked a stress on awn development and differentially altered the expression ofA andB.

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Zusammenfassung An 4 isogenen Gerstenlinien, die sich durch zwei Gene für Grannenbildung (A undB) und entsprechende kurze Kopplungsblocks unterscheiden, wurde zwei Jahre lang die Länge der Grannen bei verschiedener Standdichte (0,002 bis 3,345 m² je Pflanze) untersucht. Bei dichtem Bestand ergab sich eine Beeinträchtigung der Grannenbildung, der viertelbegrannte Genotyp (aaBB) wurde phänotypisch grannenlos (aabb). Die Ergebnisse stimmten in beiden Jahren überein, der Effekt Genotyp x Standdichte hatte den Hauptanteil an der Interaktionsvarianz Genotyp: Umwelt. Additive ( _A , _B ) und additive x additive ( _AB ) Genwirkungen wurden bei jeder Standdichte für die Grannenlänge der Seiten-und Mittelährchen errechnet. Bei den seitlichen Grannen wurde _AB nicht beeinflußt, aber _A und _B erhöhten sich mit abnehmender Standdichte. Im Gegensatz dazu gingen bei den mittleren Grannen _A und _AB zurück, während für _B bei abnehmender Standdichte ein Ansteigen festzustellen war.Messungen der mittleren Grannen jeder Ähre zeigten, daß hohe standdichte der Pflanzen die Grannenbildung am meisten in der unteren Hälfte der Ähre reduzierte. Das ist die Zone, in der sich die Grannen am schnellsten differenzieren, und da die Halm- und Ährenwachstumsraten durch hohe Standdichte stark gesteigert wurden, scheint das schnelle Wachstum auf die Grannenentwicklung hemmend einzuwirken und die Manifestierung vonA undB unterschiedlich abzuändern.

     

Vitalfärbung mit Derivaten des Phenothiazins

Zusammenfassung Zellkulturen wurden vergleichend mit Handelsfarbstoffen und gereinigten Farbstoffen aus der Phenothiazingruppe (Thionin und seine methylierten Homologe — Azurfarbstoffe — bis zum Methylenblau vitalgefärbt.Granuläre Farbstoffspeicherung wird erst dann beobachtet, wenn im zweifach aminosubstituierten Phenothiazin (Thionin) mindestens zwei Methylgruppen gegen Protonen an den Aminogruppen ausgetauscht worden sind, wie dies bei Azur A der Fall ist.Dieser Befund läßt sich nur bei Verwendung gereinigter Farbstoffe erheben. Die hier verwendeten Handelsfarbstoffe Azur C sind in solchem Ausmaß mit höher methylierten Homologen vermischt, daß deren Effekt eine Eignung des Azur C zur granulären Farbstoffspeicherung vortäuscht. Gereinigtes Azur C ist dazu jedoch ungeeignet.Phasenoptisch erscheint die mit Azur A, Azur B und Methylenblau erreichte Farbstoffspeicherung mehr vakuolär als granulär. Die vom jeweils verwendeten Farbstoff induzierten vakuolären Einschlüsse zeigen morphologische Eigenheiten.Die Befunde werden diskutiert, unter besonderer Berücksichtigung der mit den kationischen Farbstoffen vermutlich reagierenden anionischen zellulären Bestandteilen.

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Vital staining with phenothiazine derivativesComparative application of commercial and purified dyes

Summary In a comparative study cells grown in monolayer have been vitally stained with commercial dye samples and dyes purified by thin layer chromatography and column chromatography. The dyes used were derivatives of amino-substituted phenothiazine (thionine to methylene blue).Granular storage of dyes has been observed only after the protons of the amino groups had at least been substituted by two methyl groups, as represented by the compound azure A.This observation is based on the use of purified dyes. Commercial samples of azure C are mixed with fractions of the higher methylated homologues of thionine to a degree that these impurities imply suitability of azure C for intracytoplasmic granular storage. Purified azure C, however, does not induce formation of cytoplasmic vacuoles.In the phase contrast microscope, inclusions formed under the influence of azure A, azure B and methylene blue exhibit a more vacuolar than granular appearance. There are morphologic differences, between vacuoles formed under the influence of the respective dyes.The observations are discussed with special regard to the anionic cellular constituents supposed to react with the cationic dyes.

Die Arbeit wurde mit Unterstützung der F. Hoffmann-La Roche und Co. AG., Basel, durchgeführt.     

Synaptische Strukturen und Elementargranula in der Neurohypophyse des Meerschweinchens

Zusammenfassung Die Ultrastruktur des Nucleus infundibularis tuberis, der Zona interna, der Zona externa und des Hypophysenhinterlappens von Meerschweinchen wird beschrieben. Vergleichende Beobachtungen an den Nervenfasern der genannten Gebiete zeitigen folgende Ergebnisse:Die Axone der Zona interna und des Hypophysenhinterlappens enthalten gleichgeartete, große neurosekretorische Elementargranula (1,400 Å). Die Axonquerschnitte im Bereich des Nucleus infundibularis tuberis und der Zona externa weisen Granula gleichen Kalibers (800 Å) auf und lassen damit auf einen funktionell-morphologischen Zusammenhang des Nucleus infundiburis und der Zona externa schließen. Ob die kleinen Elementargranula das morphologische Substrat der sogenannten releasing factors darstellen oder ob es sich um adrenerge Axone und Endigungen mit typischen Katecholamingranula handelt, ist nicht zu klären.Es wird unterschieden zwischen echten Synapsen und synapsenähnlichen Kontakten. Nur erstere zeigen alle klassischen Synapsenmerkmale. Ihnen sind im Bereich der Neurohypophyse axosomatische und interaxonale Synapsen zuzuordnen. Zona externa und Hypophysenhinterlappen stellen neurohämale Kontaktzonen dar und zeichnen sich durch gleichartig konstruierte Synapsen aus. Neben interaxonalen Synapsen treten vor allem neurokapilläre Kontakte in den Vordergrund. In der Zona externa sind die Tanyzyten synaptisch mit Axonen verknüpft, so wie im Hypophysenhinterlappen die Pituizyten synaptische Verbindungen mit Nervenfasern eingehen. Die synapsenähnlichen Bildungen im Verlauf und an den Enden der Axone können somit neurokapillärer, neurotanyzytärer und neuropituizytärer Natur sein. Sie enthalten neben den synaptischen Vesikeln auch meist kleine oder große Elementargranula. Die ähnliche Morphologie der synaptischen Bildungen in der Zona externa und im Hinterlappen läßt einen gleichgearteten Inkretionsmechanismus beider neurohypophysärer Abschnitte vermuten. Tanyzyten und Pituizyten könnten dabei eine Überträgerfunktion ausüben. Eine rezeptorische Funktion der Tanyzyten wird gleichfalls diskutiert.Die Drüsenzellen der Pars intermedia der Hypophyse sind durch direkte neuroglanduläre Kontakte mit den Neuronen des Hypothalamus verknüpft. Die Axone stülpen sich hierbei tief in das Zytoplasma der Drüsenzellen ein. Es entstehen dadurch beim Meerschweinchen drei nervöse Endigungsformen, die Synapsen ausbilden: 1. Endigungen, die nur synaptische Vesikel enthalten; 2. Endigungen mit synaptischen Vesikeln und kleinen Granula; 3. Endigungen mit synaptischen Vesikeln und großen Granula.Zwischen den Drüsenzellen der Pars infundibularis der Adenohypophyse sind ebenfalls Axonquerschnitte zu beobachten. Es handelt sich dabei entweder um vegetative Faserbündel oder Nervenfasern mit kleinen Granula wie in der Zona externa (800 Å).

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Summary The ultrastructure of the nucleus infundibularis tuberis, the inner and outer layer of the median eminence and the posterior lobe of the guinea pig are described. Comparative studies on the nerve fibres of these regions lead to the following conclusions:The axons of the inner layer of the median eminence and of the posterior lobe contain similar types of large, neurosecretory elementary granules (Diameter 1400 Å).The cross-sections of the axons in the area of the nucleus infundibularis tuberis and of the outer layer of the median eminence exhibit the same sized granules (Diameter 800 Å), which points to a functional-morphological relationship between the two. Whether the small elementary granules represent the morphological substrate of the so-called releasing factors, or whether it is a question of adrenergic axons and terminations with typical catecholamine granules, is undecided.A distinction is made between true synapses and synapse-like contacts. Only the former display all the classical characteristics of synapses. To this sort must be classed the axosomatic and interaxonal synapses in the neurohypophysis. The external layer of the median eminence and the posterior lobe are distinguished by neurohaemal contact areas and show similarly constructed synapses. Of particular prominence, besides interaxonal synapses, are neurocapillary contiguities. Just as in the posterior lobe the pituicytes show synaptic connections with nerve fibres, so are the tanycytes in the outer layer of the median eminence in synaptical contact with axons. Thus the synapse-like formations along and at the endings of the axons can be of a neurocapillary, neurotanycytial and neuropituicytial nature. They contain, apart from the synaptic vesicles, mainly small but also large elementary granules. The similar morphology of the synaptic formations in the outer layer of the median eminence and the posterior lobe suggests the existence of a similar mechanism of internal secretion in both these neurohypophysial areas. Tanycytes and pituicytes could exercise a carrier function. A possible receptor-function of the tanycytes is considered.The glandular cells of the pars intermedia of the hypophysis are linked by means of direct neuroglandular contacts with the neurons of the hypothalamus, whereby the axons make deep incursions into the cytoplasm of the glandular cells. In the guinea pig three types of termination can be observed that form synapses: 1. terminations that contain only synaptic vesicles; 2. terminations with small granules; 3. terminations with large granules.Cross-sections of axons can also be observed between the glandular cells of the pars infundibularis of the adenohypophysis. Here they can be identified either as vegetative fibre-bundles or as nerve fibres with small granules, such as occur in the outer layer of the median eminence (Diameter 800 Å).

     

Interaction of poly(ADP-ribose)polymerase with DNA polymerase α

Homogeneously purified poly(ADP-ribose) polymerase (PARP) specifically stimulated the activity of immunoaffinity-purified calf or human DNA polymerase by about 6 to 60-fold. Apparently, poly(ADP-ribosyl)ation of DNA polymerase was not necessary for the stimulation. The effects of PARP on DNA polymerase were biphasic: at very low concentrations of DNA, it rather inhibited its activity, whereas, at higher DNA concentrations, PARP greatly stimulated it. The autopoly(ADP-ribosyl)ation of PARP suppressed both its stimulatory and inhibitory effects. By immunoprecipitation with an anti-DNA polymerase antibody, it was clearly shown that PARP may be physically associated with DNA polymerase . Stimulation of DNA polymerase may be attributed to the physical association between the two, rather than to the DNA-binding capacity of PARP, since the PARP fragment containing only the DNA binding domain showed little stimulatory activity. The existence of PARP-DNA polymerase complexes were also detected in crude extracts of calf thymus.     

Ecological theories and Dutch nature conservation

This paper aims to achieve insight into various ecological theories in the Netherlands which have different, and sometimes opposing, views on the conservation of nature. Interviews, publications and archival research brought to light four separate theories: vitalistic/holistic, dynamic, cybernetic and chaos. Diversity is reached through stability according to vitalistic/holistic and cybernetic theories, but through change and instablility according to the dynamic and chaos theories. These two groups are working apart, and continue to have their own ideas. Prediction of the future is only possible with the vitalistic/holistic and cybernetic theories. Ecologists who adhere to these theories feel responsible and able in different ways to change ecological nature towards desirable end goals. The other two theories, dynamic and chaos, appear to be less activist.     

Lysing of fresh human tumor by a cytotoxic factor derived from autologous large granular lymphocytes independently of other known cytokines

Summary During interaction with autologous tumor cells large granular lymphocytes (LGL) of cancer patients released a soluble cytotoxic factor, termed LGL-derived cytotoxic factor, which mediated lysing of autologous fresh tumor cells. The cytotoxic factor was compared with purified human recombinant cytotoxic cytokines, including tumor necrosis factor (TNF), lymphotoxin (LT), interferon (IFN) , IFN, interleukin-1 (IL-1) and IL-2. The LGL cytotoxic factor exhibited cytotoxicity against autologous and allogeneic fresh human tumor cells in an 18-h⁵¹Cr-release assay, while these target cells were resistant to lysing by any of the recombinant cytokines. Mixtures of recombinant(r) TNF, rLT, rIFN, rIFN, rIL-1 and rIL-2 were still unable to produce cytotoxic effects on fresh human tumor cells. Treatment with monoclonal and polyclonal antibodies directed against rTNF, rLT, rIFN, rIFN, or rIL-1 did not inhibit the cytotoxic activity of LGL-derived cytotoxic factor against fresh human tumor cells. Even a mixture of all the antibodies was incapable of blocking the cytolytic activity of the factor to fresh human tumor cells. Furthermore, intact LGL-mediated lysing of autologous tumor cells was not inhibited by any of the antibodies. These results may indicate that a cytotoxic factor produced by LGL in response to autologous tumor cells mediates lysing of fresh human tumor cells independently of TNF, LT, IFN, IL-1 and IL-2.     

Family studies on the third component of complement (C3), 6h1-antitrypsin polymorphism (locus E1 and E2) in the area of Marburg (Germany)

Summary The polymorphisms of the third component of complement (C3), of ₁ (₁) and of pseudocholinesterase (locus E₁ and E₂) have been investigated in 97 families with 181 children from the area of Marburg. A Mendelian inheritance was observed regarding the segregation of the phenotypes of children in the systems of C3, ₁-at and E₁-locus of pseudocholinesterase.

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Zusammenfassung 97 Familien mit 181 Kindern aus der Umgebung von Marburg wurden in bezug auf die Polymorphismen der 3. Komponente des Komplements (C3), ₁ (₁) und Pseudocholinesterase (Locus E₁ und E₂) untersucht. Die Aufspaltung in die Kinderphänotypen entspricht bezüglich C3, ₁-at und Pseudocholinesterase Locus E₁ den Mendelschen Regeln.

     

Morphologische und statistische Untersuchungen an Zellkernen von Ratten und Mäusen zur Frage einer cytologischen Geschlechtsdiagnostik

Zusammenfassung An Blutausstrichen und Gewebsschnitten von männlichen und weiblichen Mäusen und Ratten wurde das Vorkommen von geschlechtsspezifischen morphologischen Kernmerkmalen untersucht. Die Kerne der neutrophilen Granulocyten weisen bei beiden Arten keine an den Kernanhängen erkennbare Geschlechtsdifferenz auf. An den Kernen der Parenchymzellen wurde für weibliche und auch für männliche Tiere ein positiver Geschlechtsnachweis auf Grund einer charakteristischen Chromatinverteilung geführt.Wir stimmen dem Vorschlag von Th. Lüers (1957) zu, die Begriffe Geschlechts-bestimmung und Geschlechtsdifferenzierung nur in ihrer ursprünglichen Bedeutung zu verwenden.     

Die ?Stresemannsche Revolution“ in der Ornithologie des frühen 20. Jahrhunderts

Zusammenfassung Erwin Stresemann (1889–1972), Generalsekretär, Präsident und Ehrenpräsident der Deutschen Ornithologischen Gesellschaft (bzw. Deutschen Ornithologen-Gesellschaft) über 50 Jahre, war einer der hervorragendsten Ornithologen des 20. Jahrhunderts. In den 1920er und 1930er Jahren gab er den Anstoß für eine weltweite Transformation der älteren, vorwiegend systematisch-faunistischen Ornithologie zu einem Zweig der modernen Biologie und beeinflusste einen großen Kreis von Zeitgenossen (die Stresemannsche Revolution). Mit seinem maßgeblichen Aves-Band (1927–1934) des Handbuchs der Zoologie und den Dissertationen seiner Schüler entstand durch Verbindungen mit der Genetik, der funktionellen Morphologie, der Physiologie und Ethologie der Vögel eine Neue Biologische Ornithologie.

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The Stresemann Revolution in ornithology during the early 20^th century

Summary Erwin Stresemann (1889–1972), Secretary General, President and Honorary President of the Society of German Ornithologists for 50 years, was one of the outstanding ornithologists of the 20^th century. During the 1920s and 1930s, he initiated the global transformation of the traditional ornithology, which had been primarily systematic and faunistic in scope, into a branch of modern biological science, a New Avian Biology, and influenced a large circle of contemporaries (the Stresemann Revolution). He forged links, directly or indirectly, between ornithology and genetics, functional morphology, physiology and ethology, when he published his seminal volume Aves (1927–1934) in the German Handbook of Zoology, and instigated the theses of a large number of PhD students.

     

The mode of secretion of α-amylase in barley aleurone layers

The involvement of the endomenbrane system of barley (Hordeum vulgare L.) aleurone cells in the secretion of gibberellin-induced hydrolases has been investigated at the biochemical level. Our results show that at least 40–60% of the -amylase activity in homogenates of aleurone layers occurs in a membrane-bound, latent form. The latent -amylase can be assayed quantitatively following disruption of membranes by treatment with Triton X-100, ethanol, sonication, or osmotic shock and shear. The association of -amylase with the membrane is not an artifact arising from homogenization of the tissue, and acid protease is also enriched in the same subcellular fraction as the -amylase. The membrane fraction with which the -amylase is associated has many properties of the endoplasmic reticulum (ER). When membranebound -amylase is prepared in buffers containing 3 mM MgCl₂ two fractions from a sucrose step gradient contain most of the -amylase activity. These fractions are enriched in the ER marker enzyme, NADH-dependent cytochrome-c reductase, and show densities characteristic of smooth and rough ER during subsequent purification on continuous gradients. In step gradients prepared with ethylenediaminete-traacetic-acid-treated membranes, -amylase activity is contained primarily in one fraction having the density of smooth ER. Electron microscopy of the purified fractions is consistent with -amylase being associated with smooth and rough ER. However, it has not been ruled out that the enzyme is also associated with plasma membrane, Golgi membranes, or tonoplast. Examination of the isoenzyme patterns of secreted, of total-homogenate and of membrane-associated -amylases, as well as the results from pulsechase experiments using L-[³H]leucine for labeling of -amylase, are all consistent with the hypothesis that membrane-associated -amylase is an intermediate in the secretory process.Abbreviations CNTPE N-carbobenzoxy-L-tyrosine p-nitrophenylester - Cyt oxidase Cytochrome oxidase - ER endoplasmic reticulum - EDTA ethylenediaminetetraacetic acid - GA₃ gibberellic acid - IDPase inosine diphosphatase - K⁺-ATPase pH 6.5 K⁺-stimulated adenosine triphosphatase - MES 2-(N-morpholino)ethanesulfonic acid - MOPS 3-(N-morpholino)propanesulfonic acid - NADH: Cyt c reductase cyanide-insensitive NADH-linked cytochrome-c reductase - RER rough endoplasmic reticulum - Tris tris-(hydroxymethyl)-aminomethane     

Contrasting leaf and ‘ecosystem’ CO2 and H2O exchange in Avena fatua monoculture: Growth at ambient and elevated CO2

Elevated CO₂ (ambient + 35 Pa) increased shoot dry mass production in Avena fatua by 68% at maturity. This increase in shoot biomass was paralleled by an 81% increase in average net CO₂ uptake (A) per unit of leaf area and a 65% increase in average A at the ecosystem level per unit of ground area. Elevated CO₂ also increased ecosystem A per unit of biomass. However, the products of total leaf area and light-saturated leaf A divided by the ground surface area over time appeared to lie on a single response curve for both CO₂ treatments. The approximate slope of the response suggests that the integrated light saturated capacity for leaf photosynthesis is 10-fold greater than the ecosystem rate. Ecosystem respiration (night) per unit of ground area, which includes soil and plant respiration, ranged from-20 (at day 19) to-18 (at day 40) mol m^-2 s^-1 for both elevated and ambient CO₂ Avena. Ecosystem below-ground respiration at the time of seedling emergence was -10 mol m^-2 s^-1, while that occuring after shoot removal at the termination of the experiment ranged from -5 to-6 mol m^-2 s^-1. Hence, no significant differences between elevated and ambient CO₂ treatments were found in any respiration measure on a ground area basis, though ecosystem respiration on a shoot biomass basis was clearly reduced by elevated CO₂. Significant differences existed between leaf and ecosystem water flux. In general, leaf transpiration (E) decreased over the course of the experiment, possibly in response to leaf aging, while ecosystem rates of evapotranspiration (ET) remained constant, probably because falling leaf rates were offset by an increasing total leaf biomass. Transpiration was lower in plants grown at elevated CO₂, though variation was high because of variability in leaf age and ambient light conditions and differences were not significant. In contrast, ecosystem evapotranspiration (ET) was significantly decreased by elevated CO₂ on 5 out of 8 measurement dates. Photosynthetic water use efficiencies (A/E at the leaf level, A/ET at the ecosystem level) were increased by elevated CO₂. Increases were due to both increased A at leaf and ecosystem level and decreased leaf E and ecosystem ET.     

A novel wheat alpha-amylase gene (alpha-Amy3)

Summary A genomic clone of a wheat -amylase gene (Amy3/33) was identified, on the basis of hybridisation properties, as different from -Amy1 and -Amy2 genes which had been characterised previously. The nucleotide sequence revealed that this gene has the normal sequence motifs of an active gene and an open reading frame interrupted by two introns. The protein sequence encoded by this open reading frame is recognisably similar to that of -amylase from the -Amy1 and -Amy2 genes and there is high sequence homology in all three proteins at the putative active sites and Ca⁺⁺ binding region. In addition, the introns are at positions equivalent to the position of introns in the -Amy1 and -Amy2 genes. However, the sequence was less similar to -Amy1 and -Amy2 than these are to each other. Southern blot analysis showed that the Amy3/33 DNA is one of a small multigene family carried on a different chromosome (group 5) from either the -Amy1 or -Amy2 genes. A further difference from the -Amy1 and -Amy2 genes was the pattern of expression. Amy3/33 was expressed only in immature grains and, unlike the -Amy1 and -Amy2 genes, not at all in germinating aleurones. These data suggested therefore that this gene represents a third type of -amylase gene, not described before, which shares a common evolutionary ancestor with the -Amy1 and -Amy2 genes.     

Structural studies of the glycopeptides of B-chain of cinnamomin – a type II ribosome-inactivating protein by nuclear magnetic resonance

Cinnamomin is a plant type II ribosome-inactivating protein (RIP) isolated from the seeds of Cinnamomum camphora. It consists of two nonidentical polypeptide chains (A- and B-chain) held together through one disulfide linkage. Its A- and B-chain contain 0.3% and 3.9% sugars respectively. The B-chain of cinnamomin was digested by pronase E and then the liberated glycopeptides were separated from non-glycopeptides by gel filtration chromatography on a Bio-Gel P-4 column. Three crude glycopeptides were obtained by continuing chromatography over anion-exchange resin (AG1-X2) in the buffer of 2% pyridine-acetic acid (pH 8.3) with a polygradient elution system. Through further purification by the gel filtration chromatography and HPLC, three major glycopeptides, GP1, GP2 and GP3 were obtained. Mainly by two-dimensional Nuclear Magnetic Resonance (NMR) including TOCSY, DQF-COSY, NOESY, HMQC and HMBC, their primary structures were analyzed as: Man1,3Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4GlcNAc1-(Gly-)Asn-Asn-Thr(GP1), Man1,6(Man1,3)(Xyl1,2)Man1,4GlcNAc1,4(Fuc1,3)GlcNAc1-Asn-Ala-Thr(GP2),Man1,6(Man1,3)Man1,6(Man1,2 Man1,3)Man1,4GlcNAc1,4GlcNAc1-(Ala-)Asn-Gly-Thr(GP3).     

Kreuzungen zwischen Hohltaube und Ringeltaube

Zusammenfassung Die Vorgeschichte und der Verlauf von 8 Bruten eines Hohltauben-Männchens mit einem Ringeltauben-Weibchen (Columba oenas × Columba palumbus), die 16 Eier und daraus 4 lebensfähige Jungvögel (2 , 2 ) ergaben, werden geschildert.Die Bastarde sind nach Größe, Gewicht und Färbung intermediär. Sie haben den grünen Halsschild der Hohltaube, doch tritt der Einfluß der Ringeltaube insgesamt stärker hervor, z. B. in der Färbung der Brust und des Flügels, sowie in der Flügellänge, die etwa die Länge des Ringeltaubenflügels erreicht.Der Balzruf des einzigen männlichen Bastards, der das Jugendalter überlebte (HR₃), klang wie kurrrú oder rruuhg; er hatte keine Ähnlichkeit mit dem der beiden Elternarten. Auch sein Verhalten bei der Balz (Haltung beim Ruf, Beteiligung beim Nest-bau) wich von dem Verhalten männlicher Hohl- und Ringeltauben ab. Er verpaarte sich mit seiner Schwester HR₂. HR₂ trug auf einer flachen hölzernen Unterlage wenige Zweige zusammen und legte ein unbefruchtetes Ei, das es gleich im Stich ließ. Herrn Prof. Dr. Erwin Stresemann zum 70. Geburtstag gewidmet     

Mind Architecture and Brain Architecture

The use of the computer metaphor has led to the proposal of mind architecture (Pylyshyn 1984; Newell 1990) as a model of the organization of the mind. The dualist computational model, however, has, since the earliest days of psychological functionalism, required that the concepts mind architecture and brain architecture be remote from each other. The development of both connectionism and neurocomputational science, has sought to dispense with this dualism and provide general models of consciousness – a uniform cognitive architecture –, which is in general reductionist, but which retains the computer metaphor. This paper examines, in the first place, the concepts of mind architecture and brain architecture, in order to evaluate the syntheses which have recently been offered. It then moves on to show how modifications which have been made to classical functionalist mind architectures, with the aim of making them compatible with brain architectures, are unable to resolve some of the most serious problems of functionalism. Some suggestions are given as to why it is not possible to relate mind structures and brain structures by using neurocomputational approaches, and finally the question is raised of the validity of reductionism in a theory which sets out to unite mind and brain architectures.     

Observations on the reduction of non-activated carboxylates by Clostridium formicoaceticum with carbon monoxide or formate and the influence of various viologens

Crude extracts or supernatants of broken cells of Clostridium formicoaceticum reduce unbranched, branched, saturated and unsaturated carboxylates at the expense of carbon monoxide to the corresponding alcohols. The presence of viologens with redox potentials varying from E ₀=-295 to-650 mV decreased the rate of propionate reduction. The more the propionate reduction was diminished the more formate was formed from carbon monoxide. The lowest propionate reduction and highest formate formation was observed with methylviologen. The carbon-carbon double bond of E-2-methyl-butenoate was only hydrogenated when a viologen was present. Formate as electron donor led only in the presence of viologens to the formation of propanol from propionate. The reduction of propionate at the expense of a reduced viologen can be followed in cuvettes. With respect to propionate Michaelis Menten behavior was observed. Experiments are described which lead to the assumption that the carboxylates are reduced in a non-activated form. That would be new type of biological reduction.Non-standard abbreviations glc Gas liquid chromatography - HPLC high performance liquid chromatography - RP reverse phase; Mediators (the figures in parenthesis of the mediators are redox potentials E ₀ in mV) - CAV²⁺ carbamoylmethylviologen, 1,1-carbamoyl-4,4-dipyridinium dication (E ₀=-296 mV) - BV²⁺ benzylviologen, 1,1-dibenzyl-4,4-dipyridinium dication (E ₀=-360 mV) - MV methylviologen, 1,1-dimethyl-4,4-dipyridinium-dication (E ₀=-444 mV) - DMDQ²⁺ dimethyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-ethylendication (E ₀=-514 mV) - TMV²⁺ tetramethylviologen, 1,1,4,4-tetramethyl-4,4-dipyridinium dication (E ₀=-550 mV) - PDQ²⁺ propyldiquat, 2,2-dipyridino-1,1-propenyl dication (E ₀=-550 mV) - DMPDQ²⁺ dimethylpropyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-propenyl dication (E ₀=-656 mV) - PN productivity number=mmol product (obtained by the uptake of one pair of electrons) x (biocatalyst (dry weight) kg)^-1×h^-1     

The levels of ζ, γ, and δ chains in patients with Hb H disease

Summary Details are given of a study of blood samples from 24 patients with Hb H disease from different Mediterranean countries and from the Far East. Four different types of -thal-1 (--) were observed, namely-() ( 20.5-kb deletion);--MED-I ( 17.5-kb deletion);--MED-II (>26.5-kb deletion); and--SEA ( 18-kb deletion, in Orientals only). The -thal-2 was mainly of the deletion type (16 with the 3.7-kb deletion; 1 with the 4.2-kb deletion), while 4 of the 7 patients with a nondeletional type had the five-nucleotide deletion at the donor splice site of the first intron of the 2 gene. All patients had a mild-to-moderate hemolytic anemia; no significant differences in hematology were observed between the groups. Hb A₂ was decreased to about one-third of the normal level. The Hb H formation varied considerably and its quantitation was not always satisfactory. Patients with Hb H disease due to any -thal-1 combined with a nondeletional -thal-2 had the highest Hb H levels and a more marked anemia. The chain production was small and absent in patients with the MED-II type of -thal-1 because this deletion included the and genes. The highest chain levels were present in the four patients with the SEA type of -thal-1. The chain production was increased, particularly in patients with a mutation of C T at position-158 to the ^G globin gene. This chain was primarily present as Hb Bart's (or ₄) and only about 15% was recovered as Hb F or ₂₂. The evaluation of the rate of chains produced in these patients was greatly facilitated by data from one patient who had Hb H disease and a heterozygosity for the ^A-⁺. The low levels of Hb A₂ and of Hb F (relative to Hb Bart's) can be explained by a decreased affinity of chains for and chains as compared with chains in conditions of severe chain deficiency.     

Azoindoxylverfahren zum Hydrolasennachweis

Zusammenfassung Untersucht wird die Eignung verschiedener Azoindoxyl-methoden zum lichtmikroskopisch-histochemischen Nachweis der -N-Acetylglucosaminidase. Die Inkubationsmedien enthalten 0,5 mg N-Acetyl-(5-bromindol-3-yl)--d-glucosaminid (5-Br-3-Indolyl--d-N-acetylglucosaminid; 1 mg gelöst in 0,05 ml Dimethylformamid) in 1 ml 0,1 M Citronensäure-Phosphat-Puffer, pH 4,5 oder 5. Als Simultankuppler werden 0,02 ml Hexazonium-p-rosanilin oder-neufuchsin oder tetrazotiertes BAXD/ml oder 0,5 mg Fast Blue B oder Fast Garnet GBC/ml erprobt. Die besten Resultate liefert unabhängig von Gewebevorbehandlung und Organ hexazotiertes Neufuchsin.Im Vergleich zur Azofarbstoffreaktion mit Naphthol-AS-BI--d-N-acetylglucosaminid und hexazotiertem p-Rosanilin oder Neufuchsin oder tetrazotiertem BAXD liefert speziell die Azoindoxylmethode mit hexazotiertem Neufuchsin bessere oder identische Resultate. Die Indigogen-, Metallsalzund Tetrazoliumreaktion sind dem Azoindoxylverfahren meistens unterlegen; eine Ausnahme macht die Tetrazoliummethode mit BSPT.Beim Azoindoxylverfahren mit Hexazonium-p-rosanilin ist vorteilhaft, daß der Azoindoxylfarbstoff osmiert werden kann, in organischen Solventien und Kunstharzen weitgehend unlöslich ist und deshalb für die ultracytochemische Darstellung der -N-Acetylglucosaminidase in Frage kommt. Unter den übrigen Methoden ist dies nur noch mit der Tetrazoliumreaktion und BSPT der Fall; sein Formazan läßt sich ebenfalls osmieren.Mit hexazotiertem Neufuchsin zur Simultankupplung und 5-Br-3-Indolyl--d-glucosaminid als Substrat kann die -N-Acetylglucosaminidase nach Blockfixation in Form- oder Glutaraldehyd in den Lysosomen zahlreicher Rattenorgane und-gewebe einwandfrei nachgewiesen werden.

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Azoindoxyl methods for the investigation of hydrolasesIII. Histochemical studies of -d-N-acetylglucosaminidase

Summary The suitability of various azoindoxyl procedures for the light microscopical demonstration of -N-acetylglucosaminidase is described. The incubation media tried consist of 0.5 mg N-Acetyl-(5-bromindol-3-yl)--d-glucosaminide (5-Br-3-indolyl--d-N-acetylglucosaminide; 1 mg dissolved in 0.05 ml N,N-dimethylformamide) in 1 ml 0.1 M citric acid phosphate buffer, pH 4.5 or 5. 0.02 ml hexazotized p-rosaniline or new fuchsine/ml or tetrazotized BAXD or 0.5 mg Fast Blue B or Garnet GBC/ml were employed as a coupling reagent. Hexazotized new fuchsine yields the best results independent on the pretreatment of the tissue and the organ investigated followed by hexazonium-p-rosaniline.Compared with the azo dye method using naphthol AS-BI -d-N-acetyl-glucosaminide as a substrate and hexazotized p-rosaniline or new fuchsine or tetrazotized BAXD for simultaneous coupling especially the azoindoxyl technique with the new fuchsine is equivalent or superior. When the indolyl glucosaminide is used in the indigogenic, tetrazolium or metal precipitation method the results are mostly inferior with the exception of the tetrazolium reaction using BSPT.However, the main advantage of the azoindoxyl procedure is that at least the azoindoxyl dye deriving from hexazotized p-rosaniline can be osmificated and withstands treatment with organic solvents and resins. Therefore, the reaction product seems to be suitable for the electron microscopic demonstration of glucosaminidase. Among the other reaction principles this can reliably be achieved only with BSPT as a tetrazolium salt followed by osmification of its formazan.After fixation of blocks of tissue in form- or glutaraldehyde -d-N-acetylglucosaminidase can be localized with 5-Br-3-indoxyl--d-N-acetylglucosaminide as a substrate and hexazotized new fuchsine for simultaneous coupling in the lysosomes of many rat organs.