Maebashi Gunma, Japan
Maebashi Gunma, Japan

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Iizuka T.,Japan National Institute of Agrobiological Science | Sezutsu H.,Japan National Institute of Agrobiological Science | Tatematsu K.-I.,Japan National Institute of Agrobiological Science | Kobayashi I.,Japan National Institute of Agrobiological Science | And 18 more authors.
Advanced Functional Materials | Year: 2013

Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PubMed | Japan National Institute of Agrobiological Science, Gunma Sericultural Technology Center, Gunma University and RIKEN
Type: | Journal: European journal of pharmacology | Year: 2015

Opioids are the most effective and widely used drugs for pain treatment. Morphine is an archetypal opioid and is an opioid receptor agonist. Unfortunately, the clinical usefulness of morphine is limited by adverse effects such as analgesic tolerance and addiction. Therefore, it is important to study the development of novel opioid agonists as part of pain control. The analgesic effects of opioids are mediated by three opioid receptors, namely opioid -, -, and -receptors. They belong to the G protein-coupled receptor superfamily and are coupled to Gi proteins. In the present study, we developed a ligand screening system to identify novel opioid -receptor agonists that measures [(35)S]GTPS binding to cell membrane fractions prepared from the fat body of transgenic silkworms expressing -receptor-Gi1 fusion protein. We screened the RIKEN Natural Products Depository (NPDepo) chemical library, which contains 5848 compounds, and analogs of hit compounds. We successfully identified a novel, structurally unique compound, that we named GUM1, with agonist activity for the opioid -receptor (EC50 of 1.2 M). The Plantar Test (Hargreaves Method) demonstrated that subcutaneous injection of 3mg/kg of GUM1 into wild-type rats significantly extended latency time. This extension was also observed in a rat model of morphine tolerance and was inhibited by pre-treatment of naloxone. The unique molecular skeleton of GUM1 makes it an attractive molecule for further ligand-opioid receptor binding studies.

Zhu Z.,Tokyo University of Agriculture and Technology | Kikuchi Y.,Tokyo University of Agriculture and Technology | Kojima K.,Japan National Institute of Agrobiological Science | Tamura T.,Japan National Institute of Agrobiological Science | And 3 more authors.
Journal of Biomaterials Science, Polymer Edition | Year: 2010

Regenerated silk fibroin fibers from the cocoons of silkworm, Bombyx mori, were prepared with hexafluoro solvents, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) or hexafluoroacetone-trihydrate (HFA), as dope solvents and methanol as coagulation solvent. The regenerated fiber prepared from the HFIP solution showed slightly larger tensile strength when the draw ratio is 1:3 than that of native silk fiber, but the strength of the regenerated fiber with draw ratio 1:3 from the HFA solution is much lower than that of native silk fiber. This difference in the tensile strength of the regenerated silk fibers between two dope solvents comes from the difference in the long-range orientation of the crystalline region rather than that of short-range structural environment such as the fraction of β-sheet structure. The increase in the biodegradation was observed for the regenerated silk fiber compared with native silk fiber. Preparations of regenerated silk fibroin fibers containing spider silk sequences were obtained by mixing silk fibroins and silk-like proteins with characteristic sequences from a spider, Naphila clavipes, to produce drag-line silk in E. coli in the fluoro solvents. A small increase in the tensile strength was obtained by adding 5% (w/w) of the silk-like protein to the silk fibroin. The production of silk fibroin fibers with these spider silk sequences was also performed with transgenic silkworms. Small increase in the tensile strength of the fibers was obtained without significant change in the elongation-at-break. © 2010 Koninklijke Brill NV, Leiden.

Asakura T.,Tokyo University of Agriculture and Technology | Isozaki M.,Tokyo University of Agriculture and Technology | Saotome T.,Tokyo University of Agriculture and Technology | Tatematsu K.-I.,Japan National Institute of Agrobiological Science | And 3 more authors.
Journal of Materials Chemistry B | Year: 2014

Interest in vascular grafts has recently grown because more patients are undergoing procedures that involve these grafts. However, smaller grafts with diameters <6 mm made from conventional biomaterials are associated with a high incidence of thrombosis, and therefore the development of improved materials suitable for small vascular grafts is highly desirable. In this paper, four kinds of recombinant Bombyx mori silk fibroins were prepared using transgenic techniques for use as silk vascular graft with a diameter of <6 mm. The peptide sequence TS(CDPGYIGSRAS)8 derived from the laminin B1 chain or the combination of two kinds of sequences, TS(CDPGYIGSRAS)8 and (TGRGDSPAS)8 derived from fibronectin, was incorporated into the light (L)-chain or the heavy (H)-chain of the silk fibroin. The fractions of the incorporated peptide sequences range from 0.8% to 7.2% by weight in the recombinant silk fibroins. This incorporation causes a very small increase in the random coil fraction of silk fibroin and a decrease in the tensile strength. Compared with native silk fibroin, the adhesive activities of mouse endothelial and smooth muscle cells increase significantly with the recombinant silk fibroin films incorporating only the TS(CDPGYIGSRAS)8 sequence independent of the L- or H-chains. A similar tendency was observed for the high migration activities of the endothelial cells in vitro and also the longer migration distance of the endothelial cell from the anastomotic part of rat abdominal aorta in vivo when this recombinant silk fibroin was used as a coating material for the silk graft. In view of the results, the recombinant silk fibroin incorporating the laminin peptide sequence can be potentially used as a vascular graft material. This journal is © the Partner Organisations 2014.

Saotome T.,Tokyo University of Agriculture and Technology | Saotome T.,Japan Wool Textile Co. | Hayashi H.,Tokyo University of Agriculture and Technology | Tanaka R.,Tokyo University of Agriculture and Technology | And 6 more authors.
Journal of Materials Chemistry B | Year: 2015

Bombyx mori silk fibroin (SF) was successfully used for vascular grafts implanted in rats or dogs. Current transgenic technology can be developed to produce SF with improved properties. In this study, the vascular endothelial growth factor (VEGF) or the repeated fibronectin-derived sequence, TGRGDSPAS, and arginylglycylaspartic acid (RGD) were introduced into the SF heavy chain to improve its properties. A blood compatibility assay was performed to study lactose dehydrogenase (LDH) activity for both transgenic and wild type SF. Growth of human umbilical endothelial cells (HUVECs) showed greater enhancement of cellularization behaviour for the transgenic SF samples (VEGF and RGD) than for the wild type (WT) SF. VEGF SF also showed lower platelet adhesion than the RGD SF and WT SF. An in vivo implantation study supported these in vitro results. In particular, early endothelialisation was observed for VEGF transgenic SF, including the occurrence of native tissue organization at three months after implantation in rat abdominal aorta. © The Royal Society of Chemistry 2015.

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