β2-Adrenoceptor activation by zinterol causes protein phosphorylation,contractile effects and relaxant effects through a cAMP pathway in human atrium

Evidence from ventricular preparations of cat, sheep, rat and dog suggests that both ₁-adrenoceptors (₁AR) and ₂-adrenoceptors (₂AR) mediate positive inotropic effects but that only ₁AR do it through activation of a cAMP pathway. On the other hand, our evidence has shown that both ₁ AR and ₂ AR hasten relaxation of isolated human myocardium consistent with a common cAMP pathway. We have now investigated in the isolated human right atrial appendage, a tissue whose -AR comprise around 2/3 of ₁AR and 1/3 of ₂AR, whether or not ₂AR-mediated effects occur via activation of a cAMP pathway. We carried out experiments on atria obtained from patients without advanced heart failure undergoing open heart surgery. To activate ₂AR, we used the ₂AR-selective ligand zinterol. Experiments were carried out on paced atrial strips (1 Hz) and tissue homogenates and membrane particles. Zinterol caused positive inotropic and lusitropic (i.e. reduction of t_1:2 of relaxation) effects with EC₅₀ values of 3 and 2 nM, respectively. The zinterol-evoked effects were unaffected by the AR-selective antagonist CGP 20712A (300 nM) but blocked surmountably by the ₂AR-selective antagonist ICI 118551 (50 nM) which reduced both EC₅₀ values to 1 M. Zinterol stimulated adenylyl cyclase activity with an EC₅₀ of 30 nM and intrinsic activity of 0.75 with respect to (–)-isoprenaline (600 M); the effects were resistant to blockade by CGP 20712A (300 nM) but antagonised surmountably by ICI 118551 (50 nM). Zinterol bound to membrane PAR labelled with (–)-[¹²⁵I] cyanopindolol with higher affinity for ₂AR than for - 1 AR; the binding to ₂AR but not to - BAR was reduced by GTPyS (10 M). In the presence of CGP 20712A (300 nM) (–)-isoprenaline (400 M); (to activate both ₁AR and ₂AR maximally) and zinterol (10 M); increased contractile force 3.4-fold and 2.5-fold respectively and reduced relaxation tut by 32% and 18% respectively. These effects of (–)-isoprenaline and zinterol were associated (5 min incubation) with phosphorylation (pmol P/mg supernatant protein) of troponin I and C-protein to values of 8.4 ± 2.0 vs 12.4 ± 2.3 and 10.1 ± 2.5 vs 8.6 ± 1.6 respectively. (–)-Isoprenaline and zinterol also caused phosphorylation of phospholamban (1.8 ± 0.3 vs 0.4 ± 0.1 pmol P/mg respectively) specifically at serine residues. We conclude that in human atrial myocardium activation of both ₁AR and ₂AR leads to cAMP-dependent phosphorylation of proteins involved in augmenting both contractility and relaxation.     

Gene expression changes induced by bismuth in a macrophage cell line

We have investigated the effect of bismuth by autometallography, cell viability, TUNEL assay and microarray analysis of a macrophage cell line. The cells accumulate bismuth in their lysosomes in a time- and dose-dependent manner. Cell viability assays show a significant decrease in the number of viable cells related to both bismuth concentrations and exposure time. TUNEL assays after 12 h and 24 h at a bismuth-citrate concentration of 50 M revealed the presence of 30% and 70% TUNEL-positive cells, respectively, compared with 8% in the controls. We have analysed gene expression profiles for cells exposed to 50 M bismuth-citrate and for untreated controls at 12 h and 24 h by microarray analysis, which confirmed that bismuth is a powerful metallothionein inducer. A number of glycolytic enzymes are induced by bismuth, suggesting that bismuth is able to induce hypoxia-like stress. BCL2/adenovirus E1B 19-kDa-interacting protein 3 (Bnip3) has been suggested as a regulator of hypoxia-induced cell death independent of caspase-3 activation and cytochrome c release. Bnip3 is up-regulated indicating the involvement of Bnip3 as a possible mechanism for bismuth-induced cell death. Differences have been noticed in cell viability and in the modification of the mRNA expression levels at 12 and 24 h. Only 13 genes are modified at both these times, suggesting a time-dependent molecular cascade in which bismuth-exposed cells enter a dormant stage with mRNA down-regulation being followed by cell death of susceptible cells. This study was supported by the Aarhus University Research Foundation, Aase og Ejnar Danielsens Fond and Direktør Jacob Madsen og Hustrus Fond.     

Depressive effect of LHRH on the numbers of “synaptic” ribbons and spherules in the pineal gland of diestrous rats

Summary Previous studies have shown that LHRH or LHRH-like substances are present in the pineal gland. In order to investigate whether exogenous LHRH may affect the pineal gland, in the present study the effects of a single dose of LHRH (1 g, i.p.) on pineal synaptic ribbons and spherules as well as serum melatonin levels were examined in diestrous Wistar rats. One hour after the injection both ribbons and spherules exhibited a statistically significant decrease in number. Serum melatonin levels were not affected. It is concluded that humoral feedback mechanisms may exist between the hypothalamus and the pineal gland.Supported by grant Vo 135/7 within the Schwerpunktprogramm Neuroendokrinolgoie of the Deutsche Forschungsgemeinschaft     

Task Relevance Enhances Early Transient and Late Slow-Wave Activity of Distributed Cortical Sources

The primary purpose of these studies was to link together concepts related to attention/working memory and feedforward/feedback activity using MEG response profiles obtained in humans. Similar to recent studies of attention in monkeys, we show early spike-like activity (<200 ms poststimulus), most likely reflecting an early transient excitatory response mixed with feedback influences, followed by slow-wave activity (>200 ms poststimulus) in MEG cortical response profiles evoked by a visual working memory task. We experimentally dissociated the early transient activity from the later sustained activity (predominately feedback) by conducting an auditory size classification task. Words, representing common objects, evoked activity in occipital cortex (presumably due to imagery) even though visual stimuli were not present in this task. The initial spike was absent from the response profile obtained from occipital cortex, leaving only slow-wave activity, thereby allowing us to characterize or profile feedback activity in this situation. Attention or task relevance enhanced the initial spike and slow-wave activity in visually responsive areas. Prefrontal activity, along the superior frontal sulcus, evoked by the working memory task, was active later in time than initial activity in visual cortex and later than the earliest effect of attention modulation in visual cortex.     

Light and electron microscopic study of adenosine triphosphatase activity of anuran tadpole musculature

Summary The histochemical activities of succinic dehydrogenase (SDH) and Ca⁺⁺-activated ATPase (pHs 7.4 and 9.4) were studied in the larval tail musculature of Rana japonica, Rana catesbeiana and Rana ornativentris. The ATPase reaction product was detected by both light and electron microscopy. Red and white muscle fibres, as distinguished by SDH, showed high and low Ca⁺⁺-ATPase reaction, respectively, at pHs 7.4, 9.4 and following preincubation in cold K₂-EDTA solution. The ultrastructural investigation of CA⁺⁺-ATPase reaction at pH 7.4 by the Ca⁺⁺-citrophosphate technique demonstrated electron-dense reaction product in association with A, I and Z bands, intermyofibrillar (SR) compartment and the mitochondrial inner chamber. However, Pb⁺⁺ precipitation technique demonstrated Mg⁺⁺-activated myosin ATPase activity at pH 9.2 ultrastructurally. The present histochemical data suggest that the anuran larval tail red muscle fibres are possible slow, and emphasize a possible lack of correlation between the speed of contraction with their ATPase activity. Moreover, red muscle fibres of the anuran tail musculature are not equivalent to Type I fibres of higher chordates.     

Ecosystem,open thermodynamic system. The oak forest of Virelles-Blaimont

Summary An attempt is made to apply thermodynamics of irreversible processes to a forest ecosystem. It is assumed to consist of two open subsystems with chemical reactions (living organisms and abiotic environment) included in one closed system. Entropy flow and entropy production are considered taking into account entropy calculation of incoming and outgoing radiant energy. Some figures are given for the oak mixed forest of Virelles-Blaimont for one vegetation period. Estimated values are calculated for the whole biospheric-atmospheric system.The author has to thank Prof. Dr. Ulrich (Göttingen, RAF) for permission to publish this modified version of the contribution which already appeared in the Göttinger Bodenkundliche Berichte30, 131–149 (1974) (Galoux, 1974).He further thanks the Cambridge University Press for use of Figure 17 of Radiation exchange and transfer in forest ecosystem (Galoux, Woodland IBP synthesis volume actually in print, D. E. Reichle, Ed.)     

Eine zwergei-schale vom huhn

Zusammenfassung Es wird die Schale eines Zwergeies vom Huhn beschrieben. Kalkschale und Schalenmembran sind — an der Größe des Eies gemessen —dicker als gewöhnlich, und dazu erwies sich der Aufbau der mucoidreichen Schalenmembran als ungemein dicht. Bei der Entwicklung des Zwergeies setzte zunächst normale Schalenbildung ein, welche die Eisosphäriten, die Kegel und den unteren Abschnitt der Säulen lieferte. Dann aber kam es, vermutlich durch Pberangebot von Kalk, zur massenhaften Bildung von Calcosphäriten, zur Entstehung der Konglomeratschicht. Weiter verlängern sich Einzelkristalle der Konglomeratschicht unter lateraler Wachstumsbeschränkung zu aufrecht stehenden, dicht aneinanderschließenden Stelen Von den Kegeln bis zur Schalenoberfläche treten in allen Schichten Hyalosphariten auf, die als Anzeichen gestörter Schalenentwicklung gelten dürfen. Die Schale des Zwergeies enthält in allen Schichten des Exosphäriten Protoporphyrin, das sich an seiner typischen Rotfluorescenz zu erkennen gibt; insbesondere häuft es sich in der Konglomeratschicht an, bald in den Kalk aufgenommen, bald in unverkalkte organische Substanz zwischen den Kristallen eingebettet. Die zahlreichen Höckerchen des Zwergeies entstehen teils durch lokale Anhäufung von Hyalosphariten, teils aber als Extrusionen.

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Summary The shell of a dwarf-egg from the hen will be described. The calcitic shell and its membrane — in relation to the egg size — are thicker than normally; farther the structure of the shell membrane, reach on mucoid presents an exceeding density. In the development of the dwarf-egg first the normal shell production began, which supplied the eisospherites, the cones and the basal part of the columns. But then, probably effected by an abounded offer of calcite, the formation of numerous calcite spherites began, the conglomerate layer arised. Farther under lateral growth limitation monocrystals of the conglomerate layer lengthened to vertically orientated steles. In all layers of the exospheritic shell hyalospherites appear; they could be concerned as a symptom of disturbed shell formation. The shell of the dwarf-egg contains in all layers of the exospherite protoporphyrin granules, cognoscible by their typical red fluorescence. Especially the porphyrin is accumulated in the conglomerate layer, included in the calcite or embedded in the organic substance between the crystals. The numerous humps of the dwarf-egg arise partly by local aggregation of hyalospherites but partly as extrusions.

     

Translation efficiency mediated by the 5′ untranslated region greatly affects protein production in <Emphasis Type="Italic">Aspergillus oryzae</Emphasis>

We demonstrate that the 5 untranslated region (5UTR) plays an important role in determining translation efficiency in Aspergillus oryzae, using a model -glucuronidase (GUS) expression system. Alterations in the 5UTR resulted in an increase in GUS activity of up to eight-fold, without affecting mRNA levels. Moreover, using the most effective 5UTR construct, we could achieve remarkable intracellular overproduction of GUS protein; and the GUS level reached more than 50% of the total soluble protein. This is the first experimental evidence indicating the feasibility of improving recombinant protein yield by promoting translation initiation in filamentous fungi.     

The cue interaction model of depth perception: a stability analysis

In this paper, we offer a stability analysis of the cue interaction model of depth perception (House (1984)). Depth estimation using stereopsis suffers from the matching problem, the problem of correctly matching the retinal image of a feature in one eye, to its retinal image in the other eye. The Cue Interaction Model overcomes this by using monocular cues to disambiguate between the correct matches and the incorrect matches. Its decision making is based on the concept of cooperation and competition in a neural network. A general class of cooperative and competitive models has been mathematically analysed by Amari and Arbib (1977), with special attention given to equilibrium states and stability. In this paper we adapt their methods to study the above model. In particular, we prove that if the parameters are correctly tuned, the model successfully achieves its goals by suppressing the cues which represent the incorrect matches.Preparation of this paper was supported in part by NIH grant number NS-1 R01 NS24926 from NINCDS     

A model of visual development

There is now abundant evidence that the structure of the mammalian visual cortex is not innately determined but can be altered by visual experiences during a certain period at an early age. A model based on the evidence is proposed that will explain some aspects of the developmental process in the visual cortex. The model self-organizingly forms a simple cell which responds to bars and edges of a certains orientation and retinal position. The total system of the model corresponds to a hyper column which contains a complete cycle of orientational selectiviy. The model has the following three original points. i) A hyper column is finally formed in the model. ii) Most of the cells do not have orientation selectivity in the initial state. iii) It is hypothesized that the orientation continuity of the hyper column is caused by similar orientations of successive input stimuli. The results of computer simulation show that the model has the expected performance.     

Effects of cytokinin types and their concentrations on shoot proliferation and hyperhydricity in in vitro pear cultivar shoots

This study was made to clarify the effects of cytokinin type and their concentrations on shoot proliferation and hyperhydricity in in vitro Pyrus pyrifolia N. (`Hosui' and `Kosui') shoots. The shoots were subcultured in a woody plant medium supplemented with 0.5 M 3-indolyl-butyric acid, 3% (w/v) sorbitol, 0.8% (w/v) agar, and with cytokinins kinetin, 6-benzylaminopurine (BA), N-(2-chloro-4-pyridyl)-N9-phenylurea (CPPU), 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea (TDZ) added at concentrations 0.44, 4.40, 11.0 and 44.0 M. The highest number of shoots was induced by adding BA at concentration 11.0 M, then by 4.4 M BA, in both cultivars. TDZ and CPPU caused greater hyperhydricity in cultured explants than BA and kinetin. `Kosui' was more susceptible to hyperhydricity compared with `Hosui'.     

Model of neural visual system with self-organizing cells

This paper describes a model of a neural visual system of a higher animal, in which the capability of pattern recognition develops adaptively. To produce the adaptability, we adopted self-organizing cells, and with them modeled feature-detecting cells which were discovered by Hubel and Wiesel and whose plasticity was found by Blakemore and Cooper. Combining the self-organizing cells and the learning principle of a Perceptron-type system, we constructed a model of the whole visual system. The model is also equipped with an eye movement control mechanism for gazing, which reduces the number of selforganizing cells required for pattern recognition, thus contributing to their quick self-organization. Computer simulation and an experiment using a hardware simulator showed that self-organizing cells quickly become sensitive to the features often seen and that the resulted system can classify patterns with a rather small number of feature-detecting cells.     

Effect of alpha-isopropylmalate on the synthesis of RNA and protein in Neurospora

Summary The leu-3/-IPM (-isopropylmalate) regulatory system, previously shown to control several genes of leucine, isoleucine, valine, and histidine biosynthesis, appears likely to be involved also in the regulation of overall RNA and protein synthesis in Neurospora. Upon addition of -IPM the synthesis of all major species of stable RNA was found to be transiently inhibited by approximately 50%. A similar reduction was observed in overall protein synthesis. The inhibition was dependent in both cases on a functional leu-3 gene product, in conformance with previously established patterns of -IPM dependent gene regulation. The overt resemblance of the phenomenon described here to the stringent response of bacteria is noted but neither the mechanism of inhibition nor the precise role of -IPM in the process has been established.     

Negative complementation of recA protein by recA1 polypeptide: in vivo recombination requires a multimeric form of recA protein

Summary Recombination in vivo was studied in recA ^- heterozygous lacZ merodiploids by performing -galactosidase assays after infection with precA ⁺. Recombination as measured by -galactosidase production was a linear function of pecA ⁺ multiplicity of infection (MOI) when the strain contained a deletion of the chromosomal recA gene. However, when the strain carried a recA1 missense allele, a higher precA ⁺ MOI was required to obtain levels of recombination comparable to the (recA) strain, and the slope of the dose-response curve increased to approximately two. It is proposed that negative complementation occurs in mixed tetramers of wild-type and missense recA polypeptides, and that in vivo recombination is a property of a multimeric form of recA protein.     

Recurrent inversion of visual orientation in the walking fly,Drosophila melanogaster

Summary Movement-induced visual orientation in flies depends largely upon predictable responses which establish simple optomotor balance or complex pseudo search in the appropriate visual environment. Less conspicuous course diverting spontaneous actions of the flies become important in pattern-induced visual orientation. The apparently stochastic spontaneous actions of the houseflyMusca domestica still allow powerful probabilistic predictions of orientation during stationary flight (Reichardt and Poggio 1981). The predominance of non-stochastic spontaneous actions such as body saccades, focussing and shift of visual attention, plasticity of response components etc. in the fruitflyDrosophila melanogaster (Heisenberg and Wolf 1979–1980) accounts for complementary behavioural options which reduce the relevance of probabilistic predictions of orientation in this fly.The conjecture of complementary options is based on a striking antagonism between orientation towards a visual object (fixation), and orientation in the opposite direction (anti-fixation), in the walking fly. Forced choice in a multiple-Y-maze quite definitely elicits fixation in the wild type, and antifixation in the optomotor blind mutantomb ^H31 (Fig. 3). However, these effects cannot be attributed to a continuous predominance of attraction in the wild type and repellence in the mutant. This is shown under comparable conditions of free choice in an arena: The flies of either strain alternate between fixation and anti-fixation of an inaccessible visual object (Fig. 4a), and keep running to and fro between two of these objects in Buridan's paradigm (Fig. 4b, c), even if the objects are not alike (Fig. 4d). The sequence of approach, retreat and transition may be repeated a few thousand times to the point of exhaustion (Fig. 5). The process resembles the recurrent alternation of ambiguous figures such as the Necker cube in human perception. The recurrent transition between competitive objects counteracts the accumulation of spontaneous preferences, and is likely to explain the apparent lack of pattern-discrimination under operant and non-operant conditions of continued free choice inDrosophila. The conspicuous dichotomy of fixation and anti-fixation in the same environment is, as yet, incompatible with the phenomenological theory of visually controlled orientation in larger flies.Abbreviation S.E.M. standard error of the mean     

Methodological problems in evolutionary biology VII. The species plague

Various philosophers and evolutionary biologists have recently defended the thesis that species are individuals rather than sets. A decade of debates, however, did not suffice to settle the matter. Conceptual analysis shows that many of the key terms involved (individuation, evolutionary species, spatiotemporal restrictedness, individual) are ambiguous. Current disagreements should dissolve once this is recognized. Explication of the concepts involved leads to new programs for philosophical research. It could also help biology by showing how extant controversies concerning evolution may have conceptual rather than factual roots.     

The establishment and continuous subculturing of normal human adult hepatocytes: Expression of differentiated liver functions

The use of normal adult liver hepatocytes in cell culture for biochemical, toxicological and pharmacological studies has been greatly limited owing to the loss of replicative capacity and differentiated liver function. This is contrary to the ability of the liver to regenerate following injury in vivo. This suggests that liver stem or transitional hepatocytes exist that upon proper stimulus divide and differentiate into mature hepatocytes. In this study we report the establishment and culture of hepatocytes from normal human adult liver, which: (1) possess replicative capacity sufficient to subpassage 12–15 times (27–37 cumulative population doublings); (2) can be cryopreserved for subsequent use without loss of replica five capacity; and (3) upon differentiation in culture synthesize albumin and keratin 18 and metabolize benzo[a]pyrene. The ability of these cells to divide or express differentia tedfunctions appears to be due to a number of cellular, biochemical and physical characteristics that are present during the primary establishment and subsequent growth phases of the cell cultures. Disassociation of cells ffom excess liver tissue was best achieved by combining the mechanical action of the Stomacher@ with very low amounts of proteolytic enzymes and EGTA. The cell lines appeared to grow best when established and subpassaged in an rnALPHA medium supplemented with insulin, hydrocortisone, transferrin, epithelial growth factor and fetal bovine serum ® rescreened for human hepatocyte cell growth). The seeding density and cell-cell contact in culture appeared to be important for both cell division and expression of liver function. When cells were seeded at a low density and subpassaged before confluency, the cells continued to divide. Albumin and keratin 18 synthesis occurred primarily in tightly packed cell clusters. When cells were seeded at a high density, near confluency, albumin and keratin 18 synthesis occurred uniformly in all of the cells of the culture and the culture metabolized benzo[a]pyrene to water-soluble metabolites, which covalently bound to cellular DNA. This appearance of liver functions was consistent with the transition of hepatocytes to a terminally differentiated state. Nonhepatic markers, i.e., -fetoprotein, factor VIII and -glutamyl transpeptidase activity were not expressed in cells cultured at either low or high density. Thus, the data presented here indicate that normal human adult liver hepatocytes, once established in culture, can be subpassaged to a high number of population doublings, cryopreserved for later use, and modulated to express differentiated liver functions.bl]References     

Production, purification and identification of fructooligosaccharides produced by β-fructofuranosidase from Aspergillus niger IMI 303386

Aspergillus niger IMI 303386 produced higher levels of intra- and extracellular -fructofuranosidase and inulinase on inulin than on sucrose. Intracellular -fructofuranosidase from sucrose medium catalysed the best transfructosylation reaction. The concentration of fructooligosaccharides (FOS) reached a maximum in 72 h with 25% (w/v) sucrose. The FOS were purified and the main products were kestose and nystose. Inulinase hydrolysed inulin in an exofashion and released mainly fructose.     

Zur Dynamik feiner Pseudopodien von Hochmoor-Amöben

Zusammenfassung Es werden verschiedene Vorgänge an sehr zarten Pseudopodien beschrieben und mit Hilfe der an submikroskopischen Fibrillen (schraubig gebauten Mikrofibrillen und Mikroröhrchen der Elektronenmikroskopie) auftretenden Torsionsspannungen und Rotationen gedeutet.

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On the dynamics of slender pseudopodia of bog amebae

Summary Different processes which occur on very slender pseudopods are described. They are interpreted with the help of torsional forces and revolutions of the submicroscopic fibrils (helical microfibrils and microtubules in electron microscopy).

     

Polygonal inequalities as a key to neuronic equations

Neuronic or decision equations, first proposed as a mathematical model of neural activity, have shown, after their exact, compact solution was found, typical behaviours that make them natural tools for General Systems studies. It is shown here that their mathematical investigation is remarkably furthered by generalizing the triangular inequality to polygonal ones. These permit the immediate computation of the tensorial expansion of linearly separable boolean functions, and exhibit clearly the connection between their continuous and discontinuous aspects.