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  • gene expression
  • stability
  • Springer  (50)
  • American Meteorological Society
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  • 2000-2004
  • 1995-1999
  • 1990-1994  (50)
  • 1965-1969
  • 1990  (50)
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  • 1
    Digitale Medien
    Digitale Medien
    Vergleich der biologischen Aktivität und Stabilität von Menadion und Menadiol bei Hühnerküken (1990)
    Springer
    European journal of nutrition 29 (1990), S. 219-228 
    Details
    ISSN: 1436-6215
    Schlagwort(e): Vitamin K ; Menadion ; Menadiol ; Bioverfügbarkeit ; Stabilität ; Geflügel ; vitamin K ; menadione ; menadiol ; bioavailability ; stability ; poultry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft , Medizin
    Beschreibung / Inhaltsverzeichnis: Summary A bioassay of vitamin K is described, based on the prothrombin clotting time of 3-week-old, vitamin-K-depleted, and cumatetralyl-sensitized male broiler chicks, using a homologous thrombokinase preparation. With this test it could be shown that the diacetate and dibutyrate esters of menadiol are vitamin-K-active. The bioactivity of menadione from these menadiolesters amounted to about 70 % of the standard menadione from a coated menadione sodium bisulfite (Dohyfral). Menadiol seems to be temperature-resistant under such conditions, whereby two uncoated MSB preparations lost about 60 % of their activity.
    Notizen: Zusammenfassung In einem biologischen Testverfahren an Cumatetralyl sensibilisierten Küken konnte in 3 Versuchen anhand des Parameters Thromboplastinzeit mit homologer Thrombokinase gezeigt werden, da\ Menadioldiacetat und Menadioldibutyrat Vitamin-K-wirksam sind. Die biologische Wirksamkeit von Menadion aus diesen Menadiolestern betrug ca. 70 % der Menadionaktivität aus gecoatetem Menadionbisulfit (Dohyfral®). Im Gegensatz zu 2 ungeschützten MSB-Präparationen, welche bei Wärmebelastung ca. 60 % ihrer ursprünglichen Wirkung verloren, waren die Menadiolester temperaturstabil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02023079
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  • 2
    Digitale Medien
    Digitale Medien
    A bifurcation analysis of the nonlinear parametric programming problem (1990)
    Springer
    Mathematical programming 47 (1990), S. 117-141 
    Details
    ISSN: 1436-4646
    Schlagwort(e): Bifurcation ; singularity ; parametric programming ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract The structure of solutions to the nonlinear parametric programming problem with a one dimensional parameter is analyzed in terms of the bifurcation behavior of the curves of critical points and the persistence of minima along these curves. Changes in the structure of the solution occur at singularities of a nonlinear system of equations motivated by the Fritz John first-order necessary conditions. It has been shown that these singularities may be completely partitioned into seven distinct classes based upon the violation of one or more of the following: a complementarity condition, a constraint qualification, and the nonsingularity of the Hessian of the Lagrangian on a tangent space. To apply classical bifurcation techniques to these singularities, a further subdivision of each case is necessary. The structure of curves of critical points near singularities of lowest (zero) codimension within each case is analyzed, as well as the persistence of minima along curves emanating from these singularities. Bifurcation behavior is also investigated or discussed for many of the subcases giving rise to a codimension one singularity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01580856
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  • 3
    Digitale Medien
    Digitale Medien
    The spectral accuracy of a fully-discrete scheme for a nonlinear third order equation (1990)
    Springer
    Computing 44 (1990), S. 187-196 
    Details
    ISSN: 1436-5057
    Schlagwort(e): 65M10 ; Spectral method ; stability ; stability threshold
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur numerischen Lösung einer nichtlinearen Differentialgleichung dritter Ordnung, herrührend aus einem Strömungsproblem bei Gasteilchen, wird ein zeitdiskreter Pseudo-spektral-Algorithmus vorgeschlagen. Stabilität und Konvergenz des neuen Differenzenverfahrens werden analysiert. Numerische Vergleiche mit bestehenden Differenzenschemata sprechen klar zugunsten des neuen Verfahrens.
    Notizen: Abstract A time-discrete pseudospectral algorithm is suggested for the numerical solution of a nonlinear third order equation arising in fluidization. The nonlinear stability and convergence of the new scheme are analyzed. Numerical comparisons with available finite-difference methods are also reported which clearly indicate the superiority of the new scheme.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02262215
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  • 4
    Digitale Medien
    Digitale Medien
    Bifurcations in parametric nonlinear programming (1990)
    Springer
    Annals of operations research 27 (1990), S. 343-369 
    Details
    ISSN: 1572-9338
    Schlagwort(e): Bifurcation ; singularities ; continuation ; parametric nonlinear programming ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik , Wirtschaftswissenschaften
    Notizen: Abstract Bifurcation and continuation techniques are introduced as a class of methods for investigating the parametric nonlinear programming problem. Motivated by the Fritz John first-order necessary conditions, the parametric programming problem is first reformulated as a closed system of nonlinear equations which contains all Karush-Kuhn-Tucker and Fritz John points, both feasible and infeasible solutions, and relative minima, maxima, and saddle points. Since changes in the structure of the solution set and critical point type can occur only at singularities, necessary and sufficient conditions for the existence of a singularity are developed in terms of the loss of a complementarity condition, the linear dependence constraint qualification, and the singularity of the Hessian of the Lagrangian on a tangent space. After a brief introduction to elementary bifurcation theory, some simple singularities in this parametric problem are analyzed for both branching and persistence of local minima. Finally, a brief introduction to numerical continuation and bifurcation procedures is given to indicate how these facts can be used in a numerical investigation of the problem.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02055201
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  • 5
    Digitale Medien
    Digitale Medien
    Queues with service times and interarrival times depending linearly and randomly upon waiting times (1990)
    Springer
    Queueing systems 6 (1990), S. 335-351 
    Details
    ISSN: 1572-9443
    Schlagwort(e): State-dependent service and interarrival times ; Lindley equation ; recursive stochastic equations ; stability ; stochastic comparisons ; normal approximations ; scheduling arrivals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We consider a modification of the standardG/G/1 queue with unlimited waiting space and the first-in first-out discipline in which the service times and interarrival times depend linearly and randomly on the waiting times. In this model the waiting times satisfy a modified version of the classical Lindley recursion. We determine when the waiting-time distributions converge to a proper limit and we develop approximations for this steady-state limit, primarily by applying previous results of Vervaat [21] and Brandt [4] for the unrestricted recursionY n+1=C n Y n +X n . Particularly appealing for applications is a normal approximation for the stationary waiting time distribution in the case when the queue only rarely becomes empty. We also consider the problem of scheduling successive interarrival times at arrival epochs, with the objective of achieving nearly maximal throughput with nearly bounded waiting times, while making the interarrival time sequence relatively smooth. We identify policies depending linearly and deterministically upon the work in the system which meet these objectives reasonably well; with these policies the waiting times are approximately contained in a specified interval a specified fraction of time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02411482
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  • 6
    Digitale Medien
    Digitale Medien
    Netwon interpolation at Leja points (1990)
    Springer
    BIT 30 (1990), S. 332-346 
    Details
    ISSN: 1572-9125
    Schlagwort(e): 65D05 ; polynomial interpolaton ; Newton form ; stability ; Leja points ; ordering of interpolation points
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract The Newton form is a convenient representation for interpolation polynomials. Its sensitivity to perturbations depends on the distribution and ordering of the interpolation points. The present paper bounds the growth of the condition number of the Newton form when the interpolation points are Leja points for fairly general compact sets K in the complex plane. Because the Leja points are defined recursively, they are attractive to use with the Newton form. If K is an interval, then the Leja points are distributed roughly like Chebyshev points. Our investigation of the Newton form defined by interpolation at Leja points suggests an ordering scheme for arbitrary interpolation points.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02017352
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  • 7
    Digitale Medien
    Digitale Medien
    Sur l'instabilite de certaines positions d'equilibre relatif dans le probleme des n corps (1990)
    Springer
    Celestial mechanics and dynamical astronomy 49 (1990), S. 219-231 
    Details
    ISSN: 1572-9478
    Schlagwort(e): n-body problem ; stability ; relative equilibrium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Beschreibung / Inhaltsverzeichnis: Abstract We prove in this paper the instability, for all n ⩾ 4, of the configurations of relative equilibrium in the n-body problem where the n bodies submitted to newtonian mutual attractions are at the vertices of a regular polypon with n sides. For this proof we show that the equations of variations projected to the n bodies plan P have at least two conjugate characteristic exponents with a strictly positive real part; while these equations projected to an orthogonal axis to P have some solutions with secular terms.
    Notizen: Resumé On démontre dans cet article l'instabilité, pour tout n ⩾ 4, des configurations d'équilibre relatif dans le problème des n corps, oú les n corps soumises aux attractions newtonniennes mutuelles se trouvent aux sommets d'un polygone régulier de n cotés. La preuve consiste à montrer que les équations aux variations, projetées sur le plan P des n corps, possèdent au moins deux exposants caractéristiques complexes connugués dont la parr'e réelle est strictement positive; alors que ces equations projetées sur un axe orthogonal à P possèdent des solutions ayant des termes séculaires.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00049414
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  • 8
    Digitale Medien
    Digitale Medien
    The dynamics of solar sails with a non-point source of radiation pressure (1990)
    Springer
    Celestial mechanics and dynamical astronomy 49 (1990), S. 249-264 
    Details
    ISSN: 1572-9478
    Schlagwort(e): Solar sails ; radiation pressure ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The form of the solar radiation pressure on a heliocentric orbiting solar sail is obtained for a finite angular sized and limb darkened solar disk by the use of the radiation pressure tensor. It is found that the usual inverse square variation of the solar radiation pressure is modified by the finite angular size, and to a lesser extent by the solar limb darkening. The actual magnitude of the modification is in itself small, except at close heliocentric distances. However, its existence has implications for the dynamical stability of solar sails both in parked and circular orbital configurations and for the accuracy of trajectory calculations, particularly for sails in the inner solar system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00049416
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  • 9
    Digitale Medien
    Digitale Medien
    The influence of a flood event on phytoplankton succession (1990)
    Springer
    Aquatic sciences 52 (1990), S. 330-344 
    Details
    ISSN: 1420-9055
    Schlagwort(e): Flood ; phytoplankton succession ; reversion ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of the August 1987 River Reuss flood event on the phytoplankton biocoenosis in Lake Uri (Urnersee, part of Lake Lucerne, Switzerland) was investigated firstly by comparing biological, chemical and physical data sampled before the event with equivalent data sampled after the event; and secondly by comparing the phytoplankton succession in 1987 with that occurring in the “floodfree” year 1989. As a consequence of the flood, the physical and chemical environment of the phytoplankton was found to have undergone a change which resulted in an alteration in the composition of the phytoplankton community. The phytoplankton community existing previous to the flood event, which had been dominated byTabellaria fenestrata sensu Husted 1930 (K-strategist), was replaced by a biocoenosis characterized mainly by various species of flagellates, which represent a typical spring successional stage (r-strategists). After the externally-imposed perturbation, the return to stable physical and chemical conditions was followed by the re-establishment of the successional stage which had existed before the flood (termed “reversion” by Reynolds, 1980).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00879761
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  • 10
    Digitale Medien
    Digitale Medien
    Developmental changes of aldehyde dehydrogenase isozymes in human livers: Mitochondrial ALDH2 isozyme is expressed in fetal livers (1990)
    Springer
    Cellular and molecular life sciences 46 (1990), S. 747-750 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Aldehyde dehydrogenase ; developmental changes ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Previous reports suggested that the major cytosolic aldehyde dehydrogenase (ALDH1) was present in fetal and infant livers, but the major mitochondrial isozyme (ALDH2) was absent or severely diminished. Re-examination by means of starch gel electrophoresis followed by enzyme activity staining, and by means of dot blot immuno-hybridization of liver samples with known genotypes of theALDH 2 locus, indicated that bothALDH 1 andALDH 2 genes are expressed in fetal and infant livers. In addition, ALDH4 isozyme was also observed. The results imply that a fetus with the ‘usual’ homozygousALDH 2 1 /ALDH 2 1 genotype, but not one with the atypicalALDH 2 1 /ALDH 2 2 orALDH 2 2 /ALDH 2 2 , is capable of detoxifying acetaldehyde transferred from the mother.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01939955
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  • 11
    Digitale Medien
    Digitale Medien
    Robust pole assignment for incomplete nonlinear decoupling applied to robots (1990)
    Springer
    Journal of intelligent and robotic systems 3 (1990), S. 259-289 
    Details
    ISSN: 1573-0409
    Schlagwort(e): Nonlinear decoupling ; feedback linearization ; functional analysis ; elastic robots ; robustness ; stability ; pole assignment ; nonlinear systems ; robot control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Maschinenbau
    Notizen: Abstract A robustness analysis and synthesis for incomplete nonlinear decoupling for a class of nonlinear systems is discussed. Rigid and elastic-joint robot models belong to this class. For the elastic case, a transformation facilitates the robustness analysis under a weak assumption. Charts with H 1- and H ∞- norms of closed-loop disturbance transfer functions of the nonlinear-decoupled system are presented for a robust pole assignment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00126073
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  • 12
    Digitale Medien
    Digitale Medien
    The effect of insertion of the maize transposable elementMutator is dependent on genetic background (1990)
    Springer
    Biochemical genetics 28 (1990), S. 9-20 
    Details
    ISSN: 1573-4927
    Schlagwort(e): mutator ; transposable element ; alcohol dehydrogenase ; maize ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract A secondary mutant, derived from an allele of maize alcohol dehydrogenase 1 (Adh1) carrying a Mutator transposable element (Mu1) in its first intron, was reported to exhibit a threefold decrease in ADH enzymatic activity and steady-state RNA levels compared to the original mutant. The original mutant,Adh1-S3034 (abbreviatedS3034), was previously characterized at the molecular level. The derivative, abbreviatedS3034b, has now been cloned; at the DNA sequence level the insertion and surroundingAdh1 sequences are indistinguishable fromS3034. Furthermore, in our lines there is no difference in relative ADH activities between products of the two putative alleles. A comparison of gene expression in heterozygotes obtained by crossing to different tester lines reveals a correlation between the measured decrease in levels of ADH polypeptide produced by the mutant allele and the background in which it is measured; this effect is distinct from any background-related variation in the expression of the progenitor allele. It does not appear to be attributable to alternative patterns of DNA modification. It appears to reflect a background-associated difference in the level of normalAdh1-RNA produced. Thus the previously reported distinction betweenS3034 andS3034b may be due to differences in the extent to which the mutant allele and a given genetic background interact to produce functionalAdh1-RNA.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00554817
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  • 13
    Digitale Medien
    Digitale Medien
    The gene coding for glutamate dehydrogenase inDrosophila melanogaster (1990)
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00554064
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  • 14
    Digitale Medien
    Digitale Medien
    Chemical marker from silk ofYponomeuta cagnagellus (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2203-2216 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Yponomeuta cagnagellus ; caterpillars ; Lepidoptera ; Yponomeutidae ; trail following ; chemical marker ; trail pheromone ; stability ; pheromone secretory site
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Trail following in lepidopterous larvae is often attributed to chemical markers, but only a few clear-cut examples are found in the literature. In this paper evidence is presented for a chemical basis of the trail following behaviour ofYponomeuta cagnagellus. (Lepidoptera: Yponomeutidae) The marker is shown to be very persistent under laboratory conditions and is water soluble. Several possible secretory sites were investigated, and it is concluded that the marker is probably secreted together with the silk from the labial gland. Problems associated with the demonstration of trail markers in caterpillars are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01026931
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  • 15
    Digitale Medien
    Digitale Medien
    The gene coding for glutamate dehydrogenase inDrosophila melanogaster (1990)
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    Details
    ISSN: 1573-4927
    Schlagwort(e): glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02401423
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  • 16
    Digitale Medien
    Digitale Medien
    Changes in alpha-globin gene expression in mice of two alpha-globin haplotypes during development (1990)
    Springer
    Biochemical genetics 28 (1990), S. 445-457 
    Details
    ISSN: 1573-4927
    Schlagwort(e): mouse ; hemoglobin ; embryonic ; adult ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Adult alpha-globin in mice is synthesized in large amounts during development, first in the primitive, nucleated erythrocytes of yolk sac origin and later in the definitive, nonnucleated erythrocytes that differentiate in the fetal liver, spleen, and bone marrow. Isoelectric focusing analysis of hemoglobins of mice with theHba g2 andHba c haplotypes shows that the ratios of alpha chain 1 to chain 5m and alpha chain 1 to chain 4 in adult hemoglobins fromHba g2 andHba c mice, respectively, change between day 11.5 and day 16.5 of gestation in nucleated red cells, while no change occurs in nonnucleated red cells. The percentage ratios of the two different alpha-globin chains are different inHba g2 andHba c mice for EII, EIII, and adult hemoglobin. In nucleated red cells of yolk sac origin, differences and changes in alpha-globin ratios are a composite of changing globin gene transcription and posttranslational competitive affinities among globins to form embryonic and adult hemoglobin tetramers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00554373
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  • 17
    Digitale Medien
    Digitale Medien
    An altered constitutive peptide in sym 5 mutants of Pisum sativum L. (1990)
    Springer
    Plant molecular biology 14 (1990), S. 207-216 
    Details
    ISSN: 1573-5028
    Schlagwort(e): developmental mutant ; gene expression ; nodule formation ; Pisum sativum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mutational analysis of Pisum sativum L. was used to search for constitutive proteins that might function in nodule formation. The sym 5 locus is a mutational hot spot, represented by seven independently derived mutant lines with decreased nodulation. Comparison of two-dimensional polyacrylamide gels of in vitro-translated root RNA showed a consistent difference in the migrational pattern of one peptide. In the nodulating parental cultivar ‘Sparkle’, a 66 kDa peptide had a pI of 5.9. In four of the five tested sym 5 mutants, the 66 kDa peptide had a more acidic pI of 5.8. This 66 kDa peptide is found in lateral root, tap root, and shoot. Its expression was independent of rhizobial inoculation, root temperature, or light.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00018561
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  • 18
    Digitale Medien
    Digitale Medien
    Molecular cloning and sequencing of a cDNA for an auxin-repressed mRNA: correlation between fruit growth and repression of the auxin-regulated gene (1990)
    Springer
    Plant molecular biology 14 (1990), S. 127-136 
    Details
    ISSN: 1573-5028
    Schlagwort(e): auxin action ; cDNA clone ; gene expression ; developmental regulation ; strawberry fruit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A complementary DNA (cDNA) library has been constructed in λgt10 from poly(A)+ mRNA isolated from auxin-deprived strawberry receptacles. By differential plaque filter hybridization, a cDNA (λSAR5) to an auxin-repressed mRNA has been isolated. The expression of the auxin-repressed gene is studied at various stages of normal fruit development and in fruits of variant strawberry genotype using λSAR5 as a probe. Northern analyses of RNA isolated from pollinated and unpollinated fruits of various developmental stages revealed that mRNA corresponding to the λSAR5 clone is repressed during normal fruit development, and the level of λSAR5 mRNA is regulated by endogenous auxin. Furthermore, results with both normal and variant genotype strawberry fruit indicate that there is a positive correlation between growth of strawberry fruit and repression of mRNA corresponding to the λSAR5 clone. The λSAR5 cDNA has been sequenced and is 723 nucleotides in length. The deduced protein has 111 amino acid residues with a molecular mass of 12.5 kDa. The putative polypeptide starts at nucleotide position 20 and ends at 352. The molecular weight of the predicted polypeptide is in agreement with the molecular weight of the in vitro translated polypeptide of hybrid selected mRNA. A comparison of the nucleotide and deduced amino acid sequence of λSAR5 with nucleotide and protein sequences in data banks has not revealed any homology to known proteins.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00018554
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  • 19
    Digitale Medien
    Digitale Medien
    Molecular cloning of cDNAs for auxin-induced mRNAs and developmental expression of the auxin-inducible genes (1990)
    Springer
    Plant molecular biology 14 (1990), S. 643-653 
    Details
    ISSN: 1573-5028
    Schlagwort(e): auxin action ; cDNA clones ; developmental regulation ; gene expression ; strawberry fruit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract By differential hybridization, two auxin-inducible cDNA clones (λSAR1 and λSAR2) have been isolated from a cDNA library constructed to poly(A)+ mRNA from auxin-treated strawberry receptacles. Both the clones have been used as probes to study the expression of the auxin-induced genes in pollinated and unpollinated fruits of various stages of development and in different organs. A high level of auxin-induced mRNAs is found in pollinated fruits as compared to unpollinated fruits of the same age, suggesting that the expression of the auxin-induced genes is developmentally regulated and the level of auxin-induced mRNAs is regulated by endogenous auxin. Furthermore, our data on the expression of λSAR1 and λSAR2 genes in pollinated and unpollinated fruits revealed a positive correlation between growth of strawberry fruit and the induction of mRNA corresponding to the λSAR1 and λSAR2 clones. Ethylene has no effect on the expression of the auxin-induced mRNAs. λSAR1 mRNA is not detected in other parts of strawberry plants whereas λSAR2 mRNA is present in roots. Furthermore, mRNA corresponding to λSAR1 and λSAR2 is not detected in other auxin-responsive plant systems such as pea epicotyls and bean explants.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00016498
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  • 20
    Digitale Medien
    Digitale Medien
    Molecular cloning of a lupin-specific gene from a cDNA library of suspension-cultured cells of Lupinus polyphyllus (1990)
    Springer
    Plant molecular biology 15 (1990), S. 175-176 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Lupinus polyphyllus ; cell culture ; cDNA clone ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00017739
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  • 21
    Digitale Medien
    Digitale Medien
    Prosomes, subcomplexes of untranslated mRNP (1990)
    Springer
    Molecular biology reports 14 (1990), S. 1-9 
    Details
    ISSN: 1573-4978
    Schlagwort(e): prosomes ; messenger RNP ; intermediate filaments ; heat shock complex ; multicatalytical protease (MCP) ; protein synthesis ; gene expression ; differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract PROSOMES are a novel class of small RNP particles of uniform morphology, but of variable RNA (pRNA) and protein composition (about 650 000 MW; 12 nm diameter in the EM). They were discovered as subcomplexes of free mRNP, tightly attached to inactive mRNA in the cytoplasm. The pRNAs hybridize stably to mRNA. Prosomes associate in vitro to mRNA and inhibit cell free protein synthesis inducing an mRNA structure unable to interact with ribosomes. Many types of prosomes were observed. The individual particle is made up by a variable combination of about 20 characteristic proteins and one or several pRNA. Some prosomal proteins are glycosylated, phosphorylated and, possibly, ADP-ribosylated and are highly conserved in evolution whilst others vary with the species and the mRNA population they are associated to. A protease activity was found associated to prosomes. The function(s) of the prosomes is(are) still unknown. The differential inhibition of in vitro protein synthesis points to a capacity to recognize mRNA and to keep it in an inactive state. The observation with the aid of monoclonal antibodies (pMABs) that prosomes and thus mRNP are attached to the intermediate filaments (IF) raises the question if one of the functions of the IF might be in the topological distribution of mRNA within the cell. Similar to the cytokeratin fibers, the prosome networks bridge neighboring cells at specific positions. — The nucleus also contains some prosomal antigens, located on chromosomes and on the nuclear matrix. Their presence and distribution in the cell compartments varies with the cell type and the prosomal antigen probed. Oocytes contain large amounts of prosomes. In embryonic development, the synthesis of individual prosomal proteins starts progressively after the blastula stage and resumes fully in gastrulation only; cleavage and blastula stage prosomes are thus of maternal origin. The nucleo-cytoplasmic distribution of prosomal antigens changes in embryos, with the stage of development and type of differentiation. In human tissues specific patterns of prosomal antigens were found in function of cell type and differentiation. In view of these data, the hypothesis may be formulated that prosomes are a population of mRNA-linked RNP which includes particles of varying individual composition and hence specificity. Attached to IF sub-networks, specific types of prosomes might accompany families of mRNA in function of the physiological state and the specialisation of given differentiated cell types. The cell-type specific organisation of the IF networks might be related to the messenger RNA complement of a given cell, and to its status of gene expression. The prosomes might thus have a function in controlling the transport, distribution and control of activity of specific mRNAs in the cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00422709
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  • 22
    Digitale Medien
    Digitale Medien
    Cytokinin enhancement of the light induction of nitrate reductase transcript levels in etiolated barley leaves (1990)
    Springer
    Plant molecular biology 14 (1990), S. 585-594 
    Details
    ISSN: 1573-5028
    Schlagwort(e): cytokinin ; gene expression ; mRNA ; nitrate reductase ; transcriptional regulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To investigate the molecular mechanism of cytokinin regulation of nitrate reductase (NR) activity, the influence of benzyladenine (BA) on the level of NR transcript was studied in etiolated barley leaves using a barley NR cDNA as a probe. Northern blot analyses of the levels of NR poly (A)+ RNA indicate that the amount present is proportional to the concentration of BA (2×10-8 to 2×10-4 M) applied to the leaves. Enhancement of NR mRNA by 2×10-5 M BA was clearly detected after 15 minutes of exposure of the leaves to light. The enhancement is cytokinin-specific and adenine is ineffective. Brief treatment with the protein synthesis inhibitor, cycloheximide, inhibited BA-enhanced NR activity but did not inhibit BA-enhanced NR transcript level, thus the enhancement was independent of concurrent protein synthesis. Nuclear runoff transcription studies showed that the enhancement of NR mRNA was at least partially due to increased transcription rates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027504
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  • 23
    Digitale Medien
    Digitale Medien
    Expression of glutamine synthetase genes in roots and nodules of Phaseolus vulgaris following changes in the ammonium supply and infection with various Rhizobium mutants (1990)
    Springer
    Plant molecular biology 14 (1990), S. 549-560 
    Details
    ISSN: 1573-5028
    Schlagwort(e): gene expression ; glutamine synthetase ; leghaemoglobin ; nitrogen metabolism ; Phaseolus vulgaris ; root nodules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this paper we have examined whether the four glutamine synthetase (gln) genes, expressed in roots and nodules of Phaseolus vulgaris are substrate-inducible by ammonium. Manipulation of the ammonium pool in roots, through addition and removal of exogenous ammonium, did not elicit any changes in the abundances of the four mRNAs thus suggesting that the gln genes in roots of this legume are neither substrate-inducible by ammonium nor derepressed during nitrogen starvation. In nodules the effect of the ammonium supply on expression of the gln genes has been examined by growing nodules under argon/oxygen atmospheres, or with a number of Fix- Rhizobium mutants, and following addition of exogenous ammonium. The results of these experiments suggest that the expression of the gln-γ gene, which is strongly induced during nodule development, is primarily under a developmental control. However nitrogen fixation appears to have a quantitative effect on expression of gln-γ as the abundance of this mRNA is about 2 to 4-fold higher under nitrogen-fixing conditions. This effect could not be mimicked by addition of exogenous ammonium and moreover is not specific to the gln-γ gene as mRNA from a leghaemoglobin gene was similarly affected. Taken together these results have failed to find an effect of ammonium on specifically inducing the expression of glutamine synthetase genes in roots and nodules of P. vulgaris.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027500
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  • 24
    Digitale Medien
    Digitale Medien
    Organ-specific modulation of gene expression in transgenic plants using antisene RNA (1990)
    Springer
    Plant molecular biology 15 (1990), S. 39-47 
    Details
    ISSN: 1573-5028
    Schlagwort(e): antisense ; gene expression ; plants ; regulation ; RNA ; transformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have shown leaf-specific inhibition GUS gene expression in transgenic Nicotiana plants using an antisense RNA with a 41-base homology spanning the translation start codon of the gene. GUS was expressed from the nominally constitutive 35S promoter and the antisense RNA was expressed from the light-regulated ca/b promoter of Arabidopsis thaliana. A range of GUS inhibition from 0 to 100% was obtained by screening a small population of transgenic plants and the specific levels of inhibition observed were stably inherited in two generations. An antiGUS ‘gene’ dosage effect was observed in plants which were homozygous for antiGUS. RNA detection results suggest that duplex formation with the 41 base pair antiGUS RNA destabilized the GUS mRNA and that an excess of antisense. RNA was not required. Our results demonstrate the potential of antisense RNA as a strategy for obtaining plant mutants, especially ‘down mutations’ in essential genes where only a short 5′ sequence of the mRNA is required. They also suggest that the ‘position effect’ on gene expression could be used in conjunction with an antisense RNA strategy to provide a versatile approach for crop improvement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00017722
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  • 25
    Digitale Medien
    Digitale Medien
    Expression of a stilbene synthase gene in Nicotiana tabacum results in synthesis of the phytoalexin resveratrol (1990)
    Springer
    Plant molecular biology 15 (1990), S. 325-335 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Nicotiana tabacum ; fungal disease resistance ; groundnut stilbene synthase ; gene expression ; resveratrol synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A gene from groundnut (Arachis hypogaea) coding for stilbene synthase was transferred together with a chimaeric kanamycin resistance gene. It was found to be rapidly expressed after induction with UV light and elicitor in tobacco cells (Nicotiana tabacum). Comparative studies of stilbene synthase mRNA synthesis in groudnut and transgenic tobacco suspension cultures revealed the same kinetics of gene expression. Stilbene synthase specific mRNA was detectable 30 minutes after elicitor induction and 10 minutes after UV irradiation. The maximum of mRNA accumulation was between 2 and 8 hours post induction. 24 hours after induction stilbene synthase mRNA accumulation ceased. Furthermore, in transgenic tobacco plants, the gene was found to be inducible in sterile roots, stems and leaves. Stilbene synthase was demonstrated in crude protein extracts from transgenic tobacco cell cultures using specific antibodies. Resveratrol, the product of stilbene synthase, was identified by HPLC and antisera raised against resveratrol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00036918
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  • 26
    Digitale Medien
    Digitale Medien
    Tissue-specific expression of a cDNA clone from cell suspension cultures ofLupinus polyphyllus (1990)
    Springer
    Plant molecular biology 14 (1990), S. 1055-1056 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Lupinus polyphyllus ; cell culture ; cDNA clone ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00019403
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  • 27
    Digitale Medien
    Digitale Medien
    A tomato cDNA inducible by salt stress and abscisic acid: nucleotide sequence and expression pattern (1990)
    Springer
    Plant molecular biology 15 (1990), S. 695-705 
    Details
    ISSN: 1573-5028
    Schlagwort(e): salt stress ; abscisic acid ; cDNA sequence ; gene expression ; LEA protein sequence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have characterized a new tomato cDNA, TAS14, inducible by salt stress and abscisic acid (ABA). Its nucleotide sequence predicts an open reading frame coding for a highly hydrophilic and glycine-rich (23.8%) protein of 130 amino acids. Southern blot analysis of tomato DNA suggests that there is one TAS14 structural gene per haploid genome. TAS14 mRNA accumulates in tomato seedlings upon treatment with NaCl, ABA or mannitol. It is also induced in roots, stems and leaves of hydroponically grown tomato plants treated with NaCl or ABA. TAS14 mRNA is not induced by other stress conditions such as cold and wounding. The sequence of the predicted TAS14 protein shows four structural domains similar to the rice RAB21, cotton LEA D11 and barley and maize dehydrin genes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00016120
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  • 28
    Digitale Medien
    Digitale Medien
    The delay of transition of a laminar boundary layer over compliant wall (1990)
    Springer
    Acta mechanica Sinica 6 (1990), S. 15-21 
    Details
    ISSN: 1614-3116
    Schlagwort(e): transition ; compliant wall ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract In a previous paper[1], a method has been developed to study the stability characteristics of laminar boundary layers over compliant walls. In this paper, the effect of double layered compliant wall and Kramer type compliant wall on delaying the transition is investigated, and it is shown that there does exist the possibility to delay the transition by applying such compliant walls.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02488453
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  • 29
    Digitale Medien
    Digitale Medien
    Genetic transfer, inheritance, and phenotypic expression of plasmid RP4::Mu cts genes inBacillus cereus (1990)
    Springer
    Bulletin of experimental biology and medicine 109 (1990), S. 389-392 
    Details
    ISSN: 1573-8221
    Schlagwort(e): plasmid ; transception ; transcipient ; segregation ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00839668
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  • 30
    Digitale Medien
    Digitale Medien
    Molecular aspects of egg-laying behavior inAplysia californica (1990)
    Springer
    Behavior genetics 20 (1990), S. 251-264 
    Details
    ISSN: 1573-3297
    Schlagwort(e): egg-laying behavior ; Aplysia ; neuropeptides ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract TheAplysia neuroendocrine system is a particularly advantageous model for cellular and molecular studies because of the relatively small number and large size of its component neurons. In addition, numerous anatomical and physiological studies have resulted in the assignment of behavioral roles to individual identified neurons. Recombinant DNA techniques have been used to isolate the genes that encode the precursors of peptides involved in egg-laying behavior. The comparison of the egg-laying hormone (ELH) gene family within the genusAplysia reveals high homologies in the overall structure of the precursors. A well-conserved tetrabasic residue has been shown to be the first endoproteolytic cleavage site of the precursor, giving rise to two intermediates, which are differentially processed and packaged. Some members of the ELH gene family are expressed specifically in the bag cell clusters or the atrial gland, respectively, providing an opportunity to study control of gene expression at the molecular level.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01067793
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  • 31
    Digitale Medien
    Digitale Medien
    Heterosis in rice hybrids (1990)
    Springer
    Euphytica 49 (1990), S. 243-247 
    Details
    ISSN: 1573-5060
    Schlagwort(e): hybrid rice ; cytoplasmic genetic male sterile line ; fertility restorer ; heterosis ; heterobeltiosis ; standard heterosis ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary One hundred and thirtysix hybrids were developed utilizing four cytoplasmic genetic male sterile lines (V 20A, Zhen Shan 97A, IR 46829A and IR 46830A) and 34 effective restorers. Heterosis, heterobeltiosis and standard heterosis were found to be significant for grain yield and other yield attributing characters in most of the hybrids. The heterosis for grain yield was mainly due to the significant heterosis for the number of spikelets per panicle, test weight and total dry matter accumulation. Interestingly, it was found that most of the higher yielding hybrids were accompanied by significant negative heterosis for harvest index. Hybrids shorter than the shortest parent and earlier than the earliest parent were not observed; hybrids with intermediate to tall plant height having nonlodging habit could be developed. Eighteen hybrids gave more than 20% grain yield than the standard checks. These were evaluated for their stable and consistent yield performance over four seasons. The results on analysis for stability parameters indicated that the hybrids V 20A × Himdhan and Zhen Shan 97A × Mahsuri were stable over environments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00036295
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  • 32
    Digitale Medien
    Digitale Medien
    An approach to determining the ecological effects of seaweed harvesting: a summary (1990)
    Springer
    Hydrobiologia 204-205 (1990), S. 15-16 
    Details
    ISSN: 1573-5117
    Schlagwort(e): community ; disturbance ; harvesting ; population ; recruitment ; seaweed ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040209
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  • 33
    Digitale Medien
    Digitale Medien
    Effects of estuarine infauna on sediment stability and particle sedimentation (1990)
    Springer
    Hydrobiologia 190 (1990), S. 263-266 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Sediments ; stability ; sedimentation ; infauna
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Secretions produced by the two estuarine benthic invertebrates Corophium volutator and Nereis diversicolor stabilise sediments by increasing their shear strength, and reduce sedimentation of previously resuspended particles. The secretions consist of 1 to 2 μm threads which bind the particles together. They are used by both species in the production of complex burrow systems in the top 15 cm of sediment. The burrow systems have been demonstrated by a new resin impregnation technique. These results have widespread implications for the stability and erosion of estuarine sediments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008194
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  • 34
    Digitale Medien
    Digitale Medien
    Inducible cellular responses to ultraviolet light irradiation and other mediators of DNA damage in mammalian cells (1990)
    Springer
    Cell biology and toxicology 6 (1990), S. 105-126 
    Details
    ISSN: 1573-6822
    Schlagwort(e): DNA damage ; DNA amplification ; ultraviolet light irradiation ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Both naturally occuring and carcinogen-induced tumors display not only point mutations in cellular oncogenes but also more complex changes in cellular oncogenes and other cellular genes. For this and other reasons, it seems likely that DNA damage in mammalian cells can induce alterations in gene expression that may have both short and long term consequences in the target cell. The purpose of this review is to summarize current available information on inducible responses to UV-irradiation and other mediators of DNA damage in mammalian cells, and to provide some working hypotheses. We have divided these responses into three time frames, immediate (0–12 hours), early (12–48) and late (beyond 48 hours). Immediate responses include the action of DNA repair enzymes, some of which are induced as a consequence of DNA damage, and transient inhibition of DNA synthesis. Within the past few years considerable evidence has accumulated that during this immediate period there is increased expression of certain cellular oncogenes, proteases and proteins whose functions remain to be identified. It is of interest that the expression of some of these genes is also induced by certain growth factors, tumor promoters and heat shock. Alterations in gene expression during the subsequent “early” period (12–48 hrs.) have not been studied in detail, but it is during this period that one can detect increased replication of several types of viruses in cells that harbor these viruses. We have examined in detail the induction of asynchronous polyoma DNA replication (APR) in a rat fibroblast cell line carrying integrated copies of this DNA. We have obtained evidence that UV-irradiation of these cells leads to the synthesis of a 40 kd protein, within the first 1–24 hrs after irradiation, that binds to a specific sequence TGACAACA in the regulatory region of polyoma DNA. We suggest that this protein acts together with other proteins to induce APR and that this serves as a useful model for understanding the mechanisms responsible for amplification of cellular genes, a phenomenon often seen in malignant tumors. Finally, we discuss how the events occurring during the immediate and early periods following DNA damage might lead to late effects in the target cell that are stable and contribute to the genotype and phenotype of some of the progeny of these cells that are destined to become tumor cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00135030
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  • 35
    Digitale Medien
    Digitale Medien
    Neuropeptide gene expression and neural activity: Assessing a working hypothesis in nucleus caudalis and dorsal horn neurons expressing preproenkephalin and preprodynorphin (1990)
    Springer
    Cellular and molecular neurobiology 10 (1990), S. 73-98 
    Details
    ISSN: 1573-6830
    Schlagwort(e): molecular biology of peptidergic neurons ; in situ hybridization ; gene expression ; preproenkephalin ; preprodynorphin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. The working hypothesis that neuropeptide gene expression in a neuron is an indicator of that neuron's physiological activity is discussed. 2. Representative examples from the literature are presented to support the hypothesis. 3. Further, we discuss the regulation of expression of two opioid peptides, preproenkephalin and preprodynorphin, in laminae I and II of the spinal cord and in nucleus caudalis of the trigeminal nuclear complex, where they may play a role in pain modulation. 4. The expression of the opioid peptide genes can be induced by both painful and nonnoxious stimuli in neurons in time-dependent and sensory-specific fashions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00733637
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  • 36
    Digitale Medien
    Digitale Medien
    Prenatal haloperidol alters the expression of DNA polymerases in brain regions of neonate rats (1990)
    Springer
    Cellular and molecular neurobiology 10 (1990), S. 281-289 
    Details
    ISSN: 1573-6830
    Schlagwort(e): haloperidol ; gene expression ; DNA polymerases ; brain development ; mesencephalon ; forebrain ; dopamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. Previous studies have reported a marked reduction in the [3H]thymidine incorporation in forebrain after administration of a dopamine antagonist such as haloperidol. 2. We have investigated the possibility that the expression levels of genes related to DNA metabolism could be altered by haloperidol treatment. 3. By Northern blot analysis, we have studied the steady-state mRNA levels for genes involved in DNA metabolism, in neonate rat mesencephalon and forebrain, after chronic prenatal blockade of dopamine receptors with haloperidol. 4. We found that the expression levels for DNA polymerases alpha and beta were clearly reduced in forebrain by haloperidol treatment. On the contrary, the expression of DNA polymerase beta was increased in mesencephalon. 5. Our results suggest that dopamine receptors occupancy may be a critical factor in controlling cell proliferation during brain development, through a mechanism(s) involving changes in the expression of DNA polymerases.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00734581
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  • 37
    Digitale Medien
    Digitale Medien
    An example of nonlinear toxic mass spreading (1990)
    Springer
    Flow, turbulence and combustion 47 (1990), S. 323-339 
    Details
    ISSN: 1573-1987
    Schlagwort(e): toxic mass spreading ; stability ; bifurcation ; propagation of front
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract A one-dimensional, nonlinear problem of reproductive toxic mass spreading is studied in this paper. The nonlinearity is due to the difference of the reproduction rates in the toxic region and the nontoxic region. Multiple steady state solutions are found and their stability and instability are proved. Due to the instability, there may exist turning points (also called saddle-node bifurcation points), at which an infinitesimal perturbation of some parameters may cause a catastrophic change in the location of the steady state toxic front (the interface of the toxic region and the nontoxic region). For the time dependent case, the propagation of the toxic front is considered. An integral equation is derived to determine the propagation of the toxic front. Some numerical results are found for a specific example.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00386242
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  • 38
    Digitale Medien
    Digitale Medien
    Arbitrary normal stress data and a fluid of differential type (1990)
    Springer
    Rheologica acta 29 (1990), S. 98-102 
    Details
    ISSN: 1435-1528
    Schlagwort(e): Fluid of differential type ; normal stresses ; thermodynamic consistency ; Trouton viscosity ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Abstract A fairly simple generalization of the grade 2 fluid is described. However, unlike the grade 2 fluid, this fluid of differential type can accomodate extremely general viscometric data and still be consistent with commonly held ideas of energy dissipation and stability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01331804
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  • 39
    Digitale Medien
    Digitale Medien
    On the stability of crystal growth (1990)
    Springer
    Journal of statistical physics 59 (1990), S. 73-101 
    Details
    ISSN: 1572-9613
    Schlagwort(e): Crystal growth ; stability ; Markov process ; ergodicity ; transience ; null recurrence ; dynamic reversibility ; surface roughness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We investigate properties of solid-on-solid models for crystal growth, involving general microscopic rates of capture of atoms by the crystal surface and of escape of atoms. The rates in this Markov process influence the stability of the growing surface. We prove, for various different ranges of the rate parameters, stability (i.e., ergodicity) and instability (i.e., nullity) of the growth process. Symmetry properties of the process, such as reversibility, dynamic reversibility, and reflection invariance, are proved or disproved under various conditions. We give a measure of surface smoothness that distinguishes between stable and unstable growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01015564
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  • 40
    Digitale Medien
    Digitale Medien
    Different regulation of mid-size neurofilament and N-myc mRNA expression during neuroblastoma cell differentiation induced by retinoic acid (1990)
    Springer
    Cellular and molecular neurobiology 10 (1990), S. 459-470 
    Details
    ISSN: 1573-6830
    Schlagwort(e): neuroblastoma ; differentiation ; gene expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. Neuroblastoma (NB) is an unusual neuroectodermal tumor showing a high degree of spontaneous regression. NB cells can be induced to differentiatein vitro by various agents. Cell differentiation results in morphological changes characteristic of the mature neuronal phenotype, including outgrowth of neuritelike structures with several interconnections. 2. Recent experiments indicate that morphological differentiation of NB cells is associated with changes in expression of N-myc, c-myc, and c-myb oncogenes and synthesis of neurofilament proteins. However, little is known about the transcription of neurofilament genes during differentiation. 3. We have analyzed the expression of both the N-myc oncogene and mid-size neurofilament (NF) genes in the LAN-1 human NB cell line, cultured in the presence of retinoic acid (RA). Continuous treatment with RA induced morphological differentiation within 5–6 days. The transcription of N-myc was down-modulated within 24 hr of the initial exposure to RA. The mid-size NF mRNA was increased at this time. The expression of N-myc was not modified in serum-deprived LAN-1 cells, indicating that N-myc transcription is unaffected by the arrest of the cells in the G1 phase. 4. We conclude that new synthesis of mid-size NF mRNA and a decrease in N-myc transcription precedede novo formation of neurite-like processes and morphological cell differentiation of neuroblastoma cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00711187
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  • 41
    Digitale Medien
    Digitale Medien
    Stability of linearly constrained convex quadratic programs (1990)
    Springer
    Journal of optimization theory and applications 64 (1990), S. 43-53 
    Details
    ISSN: 1573-2878
    Schlagwort(e): Convex quadratic programming ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper establishes a simple necessary and sufficient condition for the stability of a linearly constrained convex quadratic program under perturbations of the linear part of the data, including the constraint matrix. It also establishes results on the continuity and differentiability of the optimal objective value of the program as a function of a parameter specifying the magnitude of the perturbation. The results established herein directly generalize well-known results on the stability of linear programs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00940021
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  • 42
    Digitale Medien
    Digitale Medien
    On the boundedness and the stability properties of solution of certain fourth order differential equations (1990)
    Springer
    Applied mathematics and mechanics 11 (1990), S. 881-887 
    Details
    ISSN: 1573-2754
    Schlagwort(e): nonlinear differential equations of the four order ; boundedness ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Mathematik , Physik
    Notizen: Abstract This paper investigates equation (1) in two cases: (i)P≡0, (ii)P(≠0) satisfies ¦P (t,x,y,z,w)¦⩽(A+¦y¦+¦z¦ + ¦w¦)q(t)., where q(t) is a nonnegative function of t. For case (i) the asymptotic stability in the large of the trivial solution x=0 is investigated and for case (ii) the boundedness result is obtained for solutions of equation (1) These results improve and include several well-known results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02014354
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  • 43
    Digitale Medien
    Digitale Medien
    Stability of Gonadorelin and Triptorelin in Aqueous Solution (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 1253-1256 
    Details
    ISSN: 1573-904X
    Schlagwort(e): gonadorelin ; triptorelin ; stability ; aqueous solution ; buffers ; pH–rate profile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The influence of pH, temperature, various buffer species at different concentrations, and ionic strength on the stability of gonadorelin and triptorelin in aqueous solution has been studied using stability-indicating high-performance liquid chromatographic methods. The degradation behavior of both peptides is similar. The maximum stability of both peptides was shown to be at an approximate pH of 5.0. Acetate has the most favorable effect on stability, while phosphate causes higher degradation. Varying the concentration of acetate buffer does not affect the degradation behavior of the peptides. A higher phosphate concentration in buffer solutions causes higher degradation, however. The ionic strength of buffer solutions has no significant influence on stability. Solutions of gonadorelin and triptorelin, respectively, buffered with acetate (0.1 M, pH 5.0) with 3% (w/v) mannitol as an additive show a predicted t 90% of 9.0 years and 7.7 years at 20°C, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015981704133
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  • 44
    Digitale Medien
    Digitale Medien
    Drug-Excipient Incompatibility Studies of the Dipeptide Angiotensin-Converting Enzyme Inhibitor, Moexipril Hydrochloride: Dry Powder vs Wet Granulation (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 379-383 
    Details
    ISSN: 1573-904X
    Schlagwort(e): incompatibility screen ; moexipril ; stability ; solid state
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The drug-excipient incompatibility screen for moexipril hydrochloride (1) using various isothermal stress methods is reported herein. It was found that most of the commonly used fillers, disintegrants, lubricants, glidants, and coating agents were incompatible with 1 in dry powder mixtures; moisture and basic (or alkalizing) agents were determined to be the dominant destabilizing factors. In wet granulations, basic agents, however, were found to suppress drug degradation even in the presence of moisture. Supported by the product distribution studies, the stabilization is proposed to involve the neutralization of the acidic drug by the basic excipients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015871406549
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  • 45
    Digitale Medien
    Digitale Medien
    Synthesis, Characterization, and in Vitro Stability of Chitosan-Methotrexate Conjugates (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 418-421 
    Details
    ISSN: 1573-904X
    Schlagwort(e): chitosan-methotrexate (CMTX) macromolecular conjugate ; drug delivery ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015887910184
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  • 46
    Digitale Medien
    Digitale Medien
    Analytical Approaches to the Study of Monoclonal Antibody Stability (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 1234-1241 
    Details
    ISSN: 1573-904X
    Schlagwort(e): monoclonal antibodies ; stability ; decomposition ; characterization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The stability of two purified monoclonal antibodies, MN12 and WT31, was investigated. The monoclonal antibodies were incubated for 32 days at different pH values (ranging from 3.0 to 10.0) at 4 and 37°C. Various analytical methods were used to assess changes in physicochemical properties of the proteins. The monoclonal antibodies were more susceptible to degradation at 37°C than at 4°C. At low pH irreversible precipitation occurred. Decomposition of the proteins was enhanced at increasing pH values in the alkaline range. This was concluded from mouse IgG-specific and antigen-specific enzyme-linked immunosorbent assays, flow cytometry, analytical gel permeation chromatography, sodium dodecyl sulfate–polyacrylamide gel electrophoresis, isoelectric focusing, and immunoblotting. No substantial change in the apparent affinity constant of MN12 was observed, as determined by an affinity enzyme-linked immunosorbent assay. Fluorescence spectra, fluorescence polarization values, and fluorescence quenching parameters of MN12 and WT31 were not substantially affected, indicating that no major irreversible conformational changes had occurred. It was concluded that each of the techniques used has only limited value for stability assessment of monoclonal antibodies and, hence, that the application of several analytical techniques is essential to gain insight into monoclonal antibody stability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015925519154
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  • 47
    Digitale Medien
    Digitale Medien
    Effect of Cyclodextrin Derivatives on Indomethacin Stability in Aqueous Solution (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 484-490 
    Details
    ISSN: 1573-904X
    Schlagwort(e): cyclodextrines ; cyclodextrin derivatives ; indomethacin ; stability ; 1H-NMR.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The effect of various cyclodextrins (CD) and cyclodextrin derivatives on indomethacin stability in phosphate buffer, pH 7.4, was investigated. The influence of CD-ring size, type of substituent, degree of substitution, substitution pattern, and influence of CD concentration were monitored. The indomethacin complex in solution was studied by 1H-NMR spectroscopy to develop a molecular inclusion model. The most favorable ring size for the stabilization of indomethacin was the β-CD. The β-CD derivatives inhibited the hydrolysis of indomethacin more effectively than the parent CD. Among the studied CD derivatives, those with lipophilic substituents, such as ethyl or methyl, were superior to those with hydrophilic substitutents. The more hydroxyl groups of the glucose moiety are substituted, the better is the stabilizing effect. Further, the p-chlorobenzoic part of the indomethacin molecule is included in the CD channel.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015860531565
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  • 48
    Digitale Medien
    Digitale Medien
    Chemical Stability of Pentostatin (NSC-218321), a Cytotoxic and Immunosuppressant Agent (1990)
    Springer
    Pharmaceutical research 7 (1990), S. 452-460 
    Details
    ISSN: 1573-904X
    Schlagwort(e): pentostatin ; nucleoside ; hydrolysis ; pK a ; hairy cell leukemia ; immunosuppressant ; adenosine deaminase inhibitor ; stability ; formulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Pentostatin, an unusual nucleoside of natural origin, has been used for the treatment of hairy cell leukemia, as an immunosuppressant agent, and as an inhibitor of adenosine deaminase. The studies of the physicochemical properties and solution stability of pentostatin (1) are important to the development of a parenteral formulation for extensive preclinical and clinical testing. Pentostatin displayed apparent pK a values at 25 ± 0.1°C and ionic strength of 0.15 M of 2.03 ± 0.03 and 5.57 ± 0.14 (spectrophotometric) and 5.50 ± 0.02 (potentiometric) for N1 and the amidine nitrogen in the seven-membered ring, respectively, which are the most likely protonation sites. The rates of degradation of pentostatin were determined as a function of pH, buffer concentration, and temperature. In the pH range 1.0–4.0, pentostatin undergoes acid-catalyzed glycosidic cleavage leading to the formation of the base compound, 2, and 2-deoxyribose. A carbonium ion mechanism in which C–N bond cleavage was the rate-determining step was consistent with the data. In the pH range 6.5–10.5, the imine bond at C5 position in pentostatin is hydrolyzed to form the corresponding formamide. Pentostatin hydrolysis in this pH range was independent of pH. At pH 〉11, pentostatin decomposes to nonchromophoric products probably through multiple-step base-catalyzed hydrolytic mechanisms. Pentostatin appears to be quite stable after reconstitution of a lyophilized experimental dosage form. Care must be taken if pentostatin is extensively diluted with 5% dextrose in water, as pentostatin stability is compromised at pH values less than 5.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1015852329748
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  • 49
    Digitale Medien
    Digitale Medien
    Generalized fractional programming: Optimality and duality theory (1990)
    Springer
    Journal of optimization theory and applications 66 (1990), S. 149-159 
    Details
    ISSN: 1573-2878
    Schlagwort(e): Lagrangian functions ; optimal multipliers ; perturbation functions ; stability ; convexity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract The generalized fractional programming problem with a finite number of ratios in the objective is studied. Optimality and duality results are established, some with the help of an auxiliary problem and some directly. Convexity and stability of the auxiliary problem play a key role in the latter part of the paper.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00940538
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  • 50
    Digitale Medien
    Digitale Medien
    Regularization and stability of the constraints in the dynamics of multibody systems (1990)
    Springer
    Nonlinear dynamics 1 (1990), S. 459-475 
    Details
    ISSN: 1573-269X
    Schlagwort(e): Regularization ; stability ; constrained multibody systems ; dynamics of multibody systems ; non-holonomic ; singularity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In the analysis of multibody dynamics, we are often required to deal with singularity problems where the constraint Jacobian matrix may become less than full rank at some instantancous configurations. This creates numerical instability which will affect the performance of the mechanical system. A modification procedure of the constraints when they vanish or become linearly dependent is proposed to regularize the dynamics of the system. A distinction between the asymptotic stability due to the representation of the constraints (at the velocity and acceleration level), and the one due to the singularity is discussed in full in this paper. It is shown that Baumgarte technique could be extended to accommodate the representation of the constraints in the neighborhood of singularity. A two link planar manipulator undergoing large motion and passing through a singular configuration is used to illustrate the proposed stability technique.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01856949
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