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  • 1995-1999  (6)
  • 1975-1979  (3)
  • Biochemistry and Biotechnology  (7)
  • Atta sexdens
  • Gene expression
  • 1
    Electronic Resource
    Electronic Resource
    Induction of cardiac angiotensin I-converting enzyme with dietary NaCl-loading in genetically hypertensive and normotensive rats (1995)
    Springer
    Journal of molecular medicine 73 (1995), S. 243-248 
    Details
    ISSN: 1432-1440
    Keywords: Angiotensin I-converting enzyme ; Gene expression ; Sodium chloride ; Heart ; Inbred rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have recently shown that the angiotensin I converting enzyme (ACE) gene is linked to NaCl-loaded blood pressure in the stroke-prone spontaneously hypertensive rat (SHRSP), and that high-NaCl loading selectively stimulates ACE in the aorta of SHRSP but not in normotensive Wistar-Kyoto (WKY) rats. We therefore investigated the relationship between cardiac ACE and the development of hypertension and left ventricular hypertrophy in response to normal- and high-NaCl diet in these rats. ACE mRNA and ACE activity were measured in left ventricular tissue after completion of hemodynamic characterization of the animals. While SHRSP rats increased blood pressure (P〈0.0001) and heart rate (P〈0.005) in response to high NaCl, blood pressure remained unchanged in WKY. Similarly, relative left ventricular weight increased only in SHRSP after high NaCl (P〈0.002). A significant two- to threefold increase of cardiac ACE mRNA and fourfold stimulation of ACE enzyme activity in response to high NaCl was found in both WKY and SHRSP rats (P〈0.005). The induction of ACE gene expression was significantly more pronounced in SHRSP compared to WKY (P〈0.02), whereas no significant strain differences in left ventricular ACE activity were found after either normal- or high-NaCl diet. Thus, arterial blood pressure and left ventricular weight remained unchanged in the WKY rats despite the activation of left ventricular ACE activity after high-NaCl exposure. These results demonstrate that left ventricular ACE activity is equally upregulated in response to high-NaCl in the normotensive and hypertensive strain, independently from the development of hypertension. We conclude that the pretranslational induction of left ventricular ACE with high-NaCl loading may be important both for the regulation of cardiac angiotensins and kinins and for local therapeutic ACE inhibition in the heart during high-salt status.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189924
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The major component of the trail pheromone of the leaf-cutting ant,Atta sexdens rubropilosa forel (1979)
    Springer
    Journal of chemical ecology 5 (1979), S. 187-203 
    Details
    ISSN: 1573-1561
    Keywords: Trail pheromone ; 3-ethyl-2,5-dimethylpyrazine ; leaf-cutting ants ; Atta sexdens ; Atta cephalotes ; foraging ; bait pickup
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The major component of the trail pheromone of the South American leaf-cutting ant,Atta sexdens rubropilosa Forel, is 3-ethyl-2,5-dimethylpyrazine (II). Methyl and ethyl phenylacetate and methyl 4-methylpyrrole-2-carboxylate (I), which is the major component of the trail pheromone ofA. texana (Buckley) andA. cephalotes (L.), were also identified and may be minor components. The pheromone is stored in the poison gland.Atta sexdens sexdens (L.) also responds strongly to the pyrazine, which in large amounts evokes a weak response fromA. texana, A. cephalotes, andAcromyrmex octospinosus (Reich). Foraging workers ofAtta sexdens rubropilosa did not preferentially pick up baits impregnated with the pyrazine. The pyrazine was puffed into the nests ofA. cephalotes, and a particular response called “milling” was noted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00988234
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    An analysis of side chain interactions and pair correlations within antiparallel β-sheets: The differences between backbone hydrogen-bonded and non-hydrogen-bonded residue pairs (1995)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 22 (1995), S. 119-131 
    Details
    ISSN: 0887-3585
    Keywords: antiparallel β-sheet ; twist ; protein folding ; side chain interactions ; branched amino acids ; cystine-rich proteins ; side chain packing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cross-strand pair correlations are calculated for residue pairs in antiparallel β-sheet for two cases: pairs whose backbone atoms are hydrogen bonded together (H-bonded site) and pairs which are not (non-H-bonded site). The statistics show that this distinction is important. When glycine is located on the edge of a sheet, it shows a 3:1 preference for the H-bonded site. Thestrongest observed correlations are for pairs of disulfide-bonded cystines, many of which adopt a close-packed conformation with each cystine in a spiral conformation of opposite chirality to its partner. It is likely that these pairs are a signature for the family of small, cystine-rich proteins. Most other strong positive and negative correlations involve charged and polar residues. It appears that electrostatic compatibility is the strongest factor affecting pair correlation. Significant correlations are observed for β- and γ-branched residues inthe non-H-bonded site. An examination of the structures showsa directionality in side chain packing. There is a correlation between (1) the directionality in the packing interactions of non-H-bonded β- and γ-branched residue pairs, (2) the handedness of the observed enantiomers of chiral β-branched side chains, and (3) the handedness of the twist of β-sheet. These findings have implications for the formation of β-sheets during protein folding and the mechanism by which the sheet becomes twisted. © 1995 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prot.340220205
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Towards meeting the paracelsus challenge: The design, synthesis, and characterization of paracelsin-43, an α-helical protein with over 50% sequence identity to an all-β protein (1996)
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 24 (1996), S. 502-513 
    Details
    ISSN: 0887-3585
    Keywords: de novo design ; protein structure ; inverse folding ; genetic algorithms ; 1H NMR ; CD ; peptide ; protein folding ; methanol ; ethylene glycol ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In response to the Paracelsus Challenge (Rose and Creamer, Proteins, 19:1-3, 1994), we present here the design, synthesis, and characterization of a helical protein, whose sequence is 50% identical to that of an all-β protein. The new sequence was derived by applying an inverse protein folding approach, in which the sequence was optimized to “fit” the new helical structure, but constrained to retain 50% of the original amino acid residues. The program utilizes a genetic algorithm to optimize the sequence, together with empirical potentials of mean force to evaluate the sequence-structure compatibility. Although the designed sequence has little ordered (secondary) structure in water, circular dichroism and nuclear magnetic resonance data show clear evidence for significant helical content in water/ethylene glycol and in water/methanol mixtures at low temperatures, as well as melting behavior indicative of cooperative folding. We believe that this represents a significant step toward meeting the Paracelsus Challenge.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Efficient biokinetic experimental designs (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 17 (1975), S. 557-570 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Of the experimental methods available for obtaining data to estimate the biological kinetic parameters μm, Ks, and Yeach requires considerable experimental effort, yet often yields somewhat imprecise estimates of the parameters, particularly Ks. Therefore it would be worthwhile to seek ways to get parameter estimates of greater precision using less experimental effort. The precision of parameter estimates is strongly dependent, upon the settings of the independent, variables used in the experiments. This dependence is explained and an attempt made to show how experimental settings can be determined that lead efficiently to precise parameter estimates with minimal effort.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260170408
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  • 6
    Electronic Resource
    Electronic Resource
    Using multiresponse data to estimate biokinetic parameters (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 17 (1975), S. 571-583 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Biokinetic parameters are usually calculated from slopes and intercepts taken from plots of experimental data. One response at an item is plotted and used for parameter estimation. Aside from problems that may be caused by transformations made when the data are plotted, this approach has the weakness of not using all the data simultaneously when there is more than one response. This paper shows how multiresponse biological data can be handled to get parameter estimates that are much more precise than those obtained using conventional methods.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260170409
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  • 7
    Electronic Resource
    Electronic Resource
    Dynamic ultrafiltration model for proteins: A colloidal interaction approach (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 50 (1996), S. 125-135 
    Details
    ISSN: 0006-3592
    Keywords: ultrafiltration ; proteins ; colloidal interactions ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A rigorous dynamic mathematical model for predicting the rate of ultrafiltration of proteins has been developed. The model is based on sophisticated descriptions of the protein-protein interactions within the layer close to the membrane surface which are responsible for controlling permeation rate. Electrostatic interactions are accounted for by a Wigner-Seitz cell approach, including a numerical solution of the nonlinear Poisson-Boltzmann equation. London-van der Waals forces are calculated using a computationally efficient means of approximating screened, retarded Lifshitz-Hamaker constants. Configurational entropy effects are calculated using an equation of state giving excellent agreement with molecular dynamic data. Electroviscous effects are also taken into account. These descriptions of protein-protein interactions are used to develop an a priori model, with no adjustable parameters, that allows quantitative prediction of the rate of filtration of proteins as a function of zeta potential (and hence pH), ionic strength, applied pressure, protein size, and membrane resistance. A comparison with experimental data for the filtration of bovine serum albumin (BSA) shows that the model is in excellent agreement with such data. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Simulated dipeptide recognition by vancomycin (1997)
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 10 (1997), S. 73-87 
    Details
    ISSN: 0952-3499
    Keywords: glycopeptide antibiotics ; free energy perturbation ; molecular dynamics simulation ; molecular recognition ; computer-assisted drug design ; 2D NMR ; simulated annealing ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The antimicrobial activity of vancomycin and related glycopeptide antibiotics is due to stereospecific recognition of polypeptide components in bacterial cell walls. To better understand how these antibiotics recognize polypeptide determinants, we have developed dynamic models of the complexes formed by the vancomycin aglycon and two different dipeptide ligands, Ac-D-ala-D-ala and Ac-D-ala-gly. Molecular dynamics simulations of the two complexes, initially conditioned with distance constraints derived from two-dimensional nuclear magnetic resonance (NMR) studies, are conformationally stable and propagate in a manner consistent with the NMR-derived constraints after the constraints are removed. Free energy calculations accurately predict the relative binding affinity of these two complexes and help validate the simulation models for detailed structural analysis. Although the two ligands adopt similar conformations when bound to the antibiotic, there are clear differences in the configuration of intermolecular hydrogen bonds, the overall shape of the antibiotic, and other structural features of the two complexes. This analysis illustrates how complex structural and dynamic factors interrelate and contribute to differences in binding affinity. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Combinatorial chemistry in the discovery and development of drugs (1995)
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 64 (1995), S. 317-324 
    Details
    ISSN: 0268-2575
    Keywords: array ; combinatorial ; diversity ; library ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Comprehensive review of the tractic and strategies that are available to the drug discovery process using combinatorial techniques.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jctb.280640402
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    Paper (German National Licenses)
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