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  • Chemistry  (4)
  • Aspergillus nidulans, recombinant
  • Isamoltane
  • 1
    Electronic Resource
    Electronic Resource
    Biochemical and behavioural effects of isamoltane, a β-adrenoceptor antagonist with affinity for the 5-HT1B receptor of rat brain (1991)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 1-6 
    Details
    ISSN: 1432-1912
    Keywords: Isamoltane ; 5-HT1B Receptors ; 5-HT Autoreceptors ; 5-HT Turnover ; 5-HT Syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The biochemical and behavioural effects of isamoltane, a \-adrenoceptor and 5-HT1B receptor antagonist that has higher affinity for 5-HT1B receptors than for 5-HTIA receptors, on 5-HT neurotransmission in the rat brain were examined. In binding experiments isamoltane was found to be about five times more potent as a ligand for the 5-HT1B receptor than for the 5-HT1A receptor (Ki values 21 and 112 nmol/l, respectively). Isamoltane increased the K+-evoked overflow of 3H from 3H-5-HT loaded slices of rat occipital cortex at 0.1 μmol/l, consistent with inhibition of the terminal 5HT autoreceptor. In vivo, isamoltane significantly increased the concentration of 5-hydroxyindoleacetic acid in hypothalamus and hippocampus indicating an increased 5-HT turnover with a maximal effect at 3 mg/kg s.c. A higher dose produced a less pronounced effect. This effect did not seem to be due to the β-adrenoceptor blocking action of isamoltane since the β-adrenoceptor antagonists, (−)-alprenolol, betaxolol or ICI 118,551 had no significant effects on 5-HT turnover at 5 mg/kg s.c. Isamoltane at 3 mg/kg s.c. induced the wet-dog shake response which was blocked by the tryptophan hydroxylase inhibitor p-chlorophenylalanine. In contrast, the same response induced by the 5-HT2 receptor agonist quipazine was not blocked by pretreatment with p-chlorophenylalanine. The wet-dog shakes evoked by isamoltane and quipazine were blocked by ritanserin, which indicates that 5-HT2 receptors are involved in their expression. These observations indicate that isamoltane, by inhibiting the terminal 5-HT autoreceptors, increased the synaptic concentration of 5-HT to a level that induced a behavioural response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180669
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of cell growth and heterologous glucoamylase production in recombinant Aspergillus nidulans (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 41 (1993), S. 273-279 
    Details
    ISSN: 0006-3592
    Keywords: glucoamylase expression ; Aspergillus nidulans, recombinant ; growth kinetics ; heterologous protein production kinetics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the work, a study of cell growth and the regulation of heterologous glucoamylase synthesis under the control of the positively regulated alcA promoter in a recombinant Aspergillus nidulans is presented. We found that similar growth rates were obtained for both the host and recombinant cells when either glucose or fructose was employed as sole carbon and energy source. Use of the potent inducer cyclopentanone in concentrations greater than 3 mM resulted n maximum glucoamylase concentration and maximum overall specific glucoamylase concentration over 80 h of batch cultivation. However, cyclopentanone concentrations in excess of 3 mM also showed an inhibitory effect on spore germination as well as fungal growth. In contrast, another inducer, threonine, had no negative effect on spore germination even when concentrations of up to 100 mM were used with either glucose or fructose as carbon source. Glucoamylase synthesis in the presence of glucose plus either inducer did not begin until glucose was totally depleted, suggesting strong catabolite repression. Similar results were obtained when fructose was employed, although low levels of glucoamylase were detected before fructose depletion, suggesting partial catabolite repression. The highest enzyme concentration (570 mg/L) and overall specific enzyme concentration (81 mg/g cell) were observed in batch culture when cyclopentanone was the inducer and fructose the primary carbon source. A maximum glucoamylase concentration of 1.1 g/L and an overall specific glucoamylase concentration of 167 mg/g cell were obtained in a bioreactor using cyclopentanone as the inducer and limited-fructose feeding strategy, which nearly doubles the glucoamylase productivity from batch cultures. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260410214
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  • 3
    Electronic Resource
    Electronic Resource
    Theoretical model of the boundary condition at a fluid-porous interface (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 840-846 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An equation for the volume average fluid velocity in a boundary layer region between a fluid and a porous medium is derived. The result is valid for a general anisotropic porous medium subject to the restrictions imposed by the assumptions made in the analysis. The basic equations of motion for an incompressible Newtonian fluid with negligible inertia are used and a linear map Mij from the volume average velocity 〈v〉 into the point velocity v is assumed to exist. Using scaling arguments, an equation for 〈v〉 is found which reduces to the Darcy equation for a point entirely within the porous medium below the boundary region and to the usual Navier-Stokes equation for a point entirely within the fluid above the boundary region. The form of the equation contains two of the terms that were originally hypothesized and tested experimentally by Beavers and Joseph (1967). In particular, the following equation is obtained: \documentclass{article}\pagestyle{empty}\begin{document}$$ \left\langle {v_i } \right\rangle = - \frac{{K_{ij} }}{\mu }\frac{\partial }{{\partial x_j }}\left\langle P \right\rangle + K_{ij} L_{jmk} \frac{\partial }{{\partial x_k }}\left\langle {v_m } \right\rangle + K_{ij} N_{jm} \nabla ^2 \left\langle {v_m } \right\rangle $$\end{document} where the tensors Kij, Ljmk and Njm are mathematically defined in terms of the map Mij.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290520
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  • 4
    Electronic Resource
    Electronic Resource
    Factors affecting the heptane solubility of polypropylene polymers and yarns (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 1839-1852 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The heptane solubility of polypropylene yarns prepared under a variety of experimental conditions from several molecular weight ranges of polymers has been examined. The heptane solubilities of the yarns have been found to vary over a wide range, depending upon the conditions of extrusion during fiber formation and the subsequent degree of orientation of the fibers. The solubility of the yarns increases with higher spinning temperatures presumably as a function of the formation of low molecular weight soluble fractions formed as a result of thermal degradation. A reduction in the solubility occurs as the yarns are oriented either during the winding operation or by subsequent drawing. The reduced solubility has been explained on the basis of increased molecular alignment thereby promoting increased crystallinity as well as the possible entrapment of normally soluble atactic polymer. The fact that the polymer solubility can be decreased by bringing the polymer to a higher state of crystallinity has been shown by annealing studies. The solubilities of the original polymers, therefore, exhibit little correlation with the yarns produced from them. The solubilities of the annealed polymers, however, more closely approach the values obtained for the highly oriented yarns.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080432
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  • 5
    Electronic Resource
    Electronic Resource
    Differential method for the determination of the order of reaction and the rate constants (1982)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 535-541 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is proposed whereby the orders and rate constants for processes obeying the rate law -dA/dt = kAn may be determined. The method is illustrated in two ways. First, simulated data for processes of various orders are treated, and the treatment is shown to be capable of reproducing orders and rate constants to a high degree of accuracy. The factors affecting the accuracy with which n and k can be determined are considered. These are inaccuracy in the determination of concentration values, irregularity of the time intevals between concentration determinations, and the length of those time intervals. It is shown that if concentrations are determined at times that are close together, the effect of the other two factors is small, but if the time intervals are made longer, the errors due to the other two factors affect the calculated values of n and k much more seriously. Second, the method was applied to two homogeneous reactions, of which one was first-order and one was second order, and three heterogeneous reactions, of which one was found by the original workers to be first order, one to be zero order, and one to vary between zero and first order, depending on the initial pressure. The present method gives results in agreement with these conclusions and reproduces the rate constants to within ±5% in all cases.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550140510
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