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  • 1
    Publication Date: 2018-08-31
    Description: Microplitis demolitor (Hymenoptera: Braconidae) is a parasitoid used as a biological control agent to control larval-stage Lepidoptera and serves as a model for studying the function and evolution of symbiotic viruses in the genus Bracovirus . Here we present the M. demolitor genome (assembly version 2.0), with a genome size of 241 Mb, and a N50 scaffold and contig size of 1.1 Mb and 14 Kb, respectively. Using RNA-Seq data and manual annotation of genes of viral origin, we produced a high-quality gene set that includes 18,586 eukaryotic and 171 virus-derived protein-coding genes. Bracoviruses are dsDNA viruses with unusual genome architecture, in which the viral genome is integrated into the wasp genome and is comprised of two distinct components: proviral segments that are amplified, circularized, and packaged into virions for export into the wasp’s host via oviposition; and replication genes. This genome assembly revealed that at least two scaffolds contain both nudivirus-like genes and proviral segments, demonstrating that at least some of these components are near each other in the genome on a single chromosome. The updated assembly and annotation are available in several publicly accessible databases; including the National Center for Biotechnology Information and the Ag Data Commons. In addition, all raw sequence data available for M. demolitor have been consolidated and are available for visualization at the i5k Workspace. This whole genome assembly and annotation represents the only genome-scale, annotated assembly from the lineage of parasitoid wasps that has associations with bracoviruses (the ‘microgastroid complex’), providing important baseline knowledge about the architecture of co-opted virus symbiont genomes.
    Electronic ISSN: 2160-1836
    Topics: Biology
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Synopsis The enzyme content and the secretory behaviour of normal rat salivary glands were compared with these properties in glands made hypertrophic and hyperplastic by the chronic administration of isoproterenol. The enlarged glands displayed reductions in the concentrations of ribonuclease, deoxyribonuclease and amylase. The secretory behaviourin vivo was similar for all enzymes in both types of glands, but the enlarged glands secreted a lower percentage of their contentin vitro. The reduction in amylase activity was shown by immunological techniques to be due to a reduction in the number of enzyme molecules. The reduction in ribonuclease activity was not due to changes in the level of ribonuclease inhibitors.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-4943
    Keywords: insulin analog ; synthesis ; structure-activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An analog of human insulin, which differs from the parent molecule in that the histidine residue at position 10 of the B chain (B10) is replaced by lysine, has been synthesized and isolated in purified form. This analog, [10-lysine-B] insulin ([Lys10-B] insulin), in stimulating lipogenesis and in radioimmunoassays, exhibited potencies of 14.2% and 14.7%, respectively, as compared to the natural hormone. In insulin receptor binding in rat liver membranes, [Lys10-B] insulin was found to possess a potency of ∼17% compared to insulin. We have shown previously that substitution of the B10 polar residue histidine with the nonpolar leucine results in an analog exhibiting inin vivo assays ∼50% of the activity of the parent molecule. It is speculated that in insulin the relative size of the amino acid residue at B10, rather than its polarity, is the most important factor in maintaining a structure commensurate with high biological activity.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-4943
    Keywords: 5-Hydroxytryptophan ; tryptophan ; insulin analogs ; fluorescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Use of insulin's intrinsic tyrosine absorption and fluorescence to monitor its interaction with the insulin receptor is limited because the spectral properties of the receptor tryptophan residues mask the spectral properties of the hormone tyrosine residues. We describe the synthesis of an insulin analog where A14 tyrosine is replaced by a tryptophan analog, 5-hydroxytryptophan. This insulin is spectrally enhanced since 5-hydroxytryptophan has an absorption band above 300 nm which is at lower energies than the absorption of tryptophan. Steady-state and time-resolved fluorescence parameters indicate that 5-hydroxytryptophan reports the same information about the environment of the A14 side chain as does the corresponding tryptophan-containing insulin. The synthetic hormone is a full agonist compared to porcine insulin, but has slightly reduced specific activity. Consequently, this spectrally enhanced insulin analog will be useful for hormone-receptor interaction studies since it can be observed by both absorption and fluorescence even in the presence of the tryptophan-containing receptor.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-4943
    Keywords: Insulin analogues ; tryptophan analogues of insulin ; structure-activity relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In continuation of our efforts to study the solution structure and conformational dynamics of insulin by time-resolved fluorescence spectroscopy, we have synthesized and examined the biological activity of five insulin analogues in which selected naturally occurring residues in the A-chain have been replaced with the strongly fluorescent tryptophan residue. The potency of these analogues was evaluated in lipogenesis assays in isolated rat adipocytes, in receptor binding assays using rat liver plasma membranes, and in two cases, in receptor binding assays using adipocytes. [A3 Trp]insulin displays a potency of 3% in receptor binding assays in both liver membranes and in adipocytes, but only 0.06% in lipogenesis assays as compared to porcine insulin. [A10 Trp] insulin displays a potency ofca. 40% andca. 25% in rat liver receptor binding and lipogenesis assays, respectively. [A13 Trp]insulin displays a potency ofca. 39% in rat liver receptor binding assays, but onlyca. 9% in receptor binding in adipocytes; in lipogenesis assays, [A13 Trp] insulin displays a potency ofca. 12%, comparable to its potency in adipocyte receptor binding assays. [A15 Trp]insulin exhibits a potency of 18% and 9% in rat liver receptor binding and lipogenesis assays, respectively. The doubly substituted analogue, [A14 Trp, A19 Trp] insulin, displays a potency ofca. 0.7% in both rat liver receptor binding assays and lipogenesis assays. These data suggest two major conclusions: (1) the A3 and A15 residues lie in sensitive regions in the insulin molecule, and structural modifications at these positions have deleterious effects on biological activity of the hormone; and (2) [A13 Trp]insulin appears to be a unique case in which an insulin analogue exhibits a higher potency when assayed in liver tissue than when assayed in fat cells.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-4943
    Keywords: insulin analog ; synthesis ; structure-activity studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two analogs of sheep insulin, both differing from the native material by a single amino acid in the A chain, have been synthesized and isolated in highly purified form by procedures developed in this laboratory. In one case, the glutamine residue in position A5 was replaced by leucine ([Leu5-A]); in the other, the tyrosine residue in position A19 was replaced by phenylalanine ([Phe19-A]). The biological behavior of these analogs was compared with natural bovine insulin inin vitro tests and in receptor-binding assays, as well as in radioimmunoassay. In the stimulation of glucose oxidation by rat adipocytes, the analogs gave relative potencies of 30% and 7.8% for [Leu5-A] and [Phe19-A], respectively. Receptor-binding assays in rat liver plasma membranes showed similar behavior for both analogs. In radioimmunoassay, [Leu5-A] displayed a relative potency of 27.9%, while [Phe19-A] showed a relative potency of 19–27%, compared with bovine insulin. At high concentration, both analogs displayed the same maximal activity as bovine insulin, and the dose-response curves are essentially parallel. It is speculated that the interaction between the glutamine residue in position 5 and the tyrosine residue in position 19 of the A chain of insulin are important in maintaining a three-dimensional structure commensurate with high biological activity. The full intrinsic activity of both analogs at high concentrations and the similarity of the potency figures in receptor-binding and glucose-oxidation assays permit the further conclusion that the reduced potency in the latter assay can be ascribed wholly to the reduced binding affinity toward insulin receptors caused by the substitutions made in the analogs. The receptor-analog complexes are fully capable of triggering the next event in the chain leading to the biological response.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-4943
    Keywords: insulin analogue ; insulin-like growth factor ; metabolic assay ; mitogenic assay ; synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An analogue of insulin in which the naturally occurring tyrosine residue in position B16 is replaced by a glutamine residue has been synthesized. Glutamine appears in the corresponding position in the B-domain of the insulin-like growth factors. This analogue displays 9% of the potency of insulin in binding to the insulin receptor from rat liver plasma membranes, 17% in stimulating the conversion of [3-3H] glucose into lipids in rat adipocytes, and 23% in insulin radioimmunoassay, but 40% of the potency of insulin in stimulating DNA synthesis in cultured chick fibroblasts. The analogue is a more potent mitogen than is a hybrid molecule which contains the A-chain of insulin and the entire B-domain sequence of IGF-I.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-4943
    Keywords: Insulin analogue ; insulin-like-growth factor ; peptide synthesis ; receptor binding assay ; lipogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We report the synthesis and biological evaluation of a two-chain, disulfide-linked, insulin-like compound consisting of the B-chain of bovine insulin and an A-chain corresponding to the A- and D- domains of human insulin-like growth factor-I (IGF-I) in which the A-domain amino-acid residues -Phe49-Arg50-Ser51- found in IGF-I have been replaced by -Ala-Gly-Val-, the homologous region of sheep insulin. The compound is indistinguishable from a previously reported compound whose A-chain corresponds to the A- and D-domains of IGF-I without the substitution, in assays for insulin-like activity as well as in assays for growth-promoting activity. We conclude that these A-domain residues do not contribute significantly to the interaction of IGF-I with either insulin or IGF-I receptors.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-4943
    Keywords: IGF-I/insulin hybrid ; growth-promoting activity ; insulin activity ; structure-function relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We have synthesized an insulin-like compound, consisting of the B-chain of bovine insulin and an A-chain corresponding to the A-domain of human insulin-like growth factor-I (IGF-I), in which the isoleucine residue normally present in position 2 of the A-domain of IGF-I has been replaced with glycine. Biological evaluation of the compound indicated that its insulin-like activity (insulin receptor-binding and stimulation of lipogenesis) was 0.2%, and its growth-factor activity (stimulation of thymidine incorporation) was less than 1%, both relative to natural insulin. We conclude that interactions between IleA2 and TyrA19, which are crucial to high biological activity in insulin, are also present in IGF-I, and are equally critical for its biological activity.
    Type of Medium: Electronic Resource
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