Ken-ichi Nakajima

Learn More
Spider dragline silk is a natural fiber that has excellent tensile properties; however, it is difficult to produce artificially as a long, strong fiber. Here, the spider (Araneus ventricosus) dragline protein gene was cloned and a transgenic silkworm was generated, that expressed the fusion protein of the fibroin heavy chain and spider dragline protein in(More)
We have recently reported that Na(+)/K(+)/2Cl(-) cotransporter isoform 1 (NKCC1) plays an essential role in nerve growth factor (NGF)-induced neurite outgrowth in PC12D cells. On the other hand, it has been reported that dietary flavonoids, such as quercetin, apigenin, and luteolin, stimulate various ion transporters. In the present report, we investigated(More)
This paper reports a preparation method for silk sericin hydrogel using the Sericin-hope silkworm, whose cocoons consist almost exclusively of sericin. Sericin solution, prepared from Sericin-hope cocoons, contains intact sericin and forms elastic hydrogels with the addition of ethanol. The sericin hydrogel can be prepared without crosslinking by chemicals(More)
Weak electric fields guide cell migration, known as galvanotaxis/electrotaxis. The sensor(s) cells use to detect the fields remain elusive. Here we perform a large-scale screen using an RNAi library targeting ion transporters in human cells. We identify 18 genes that show either defective or increased galvanotaxis after knockdown. Knockdown of the KCNJ15(More)
The Na(+)/K(+)/2Cl(-) cotransporter (NKCC) mediates electroneutral transport of 2Cl(-) coupled with Na(+) and K(+) across the plasma membrane, and plays crucial roles in Cl(-) uptake into the cells, homeostasis of cellular Cl(-), and cell volume regulation. However, we have very limited information on the roles of ion transporters in neurite outgrowth in(More)
This paper reports chemical modification of silk sericin in LiCl/dimethyl sulfoxide (DMSO) solvent with 4-cyanophenyl isocyanate. Sericin is a highly hydrophilic protein secreted by Bombyx mori, serving as a protein glue in a cocoon. LiCl/DMSO was found to be a good solvent of sericin and useful for homogeneous modification of its abundant hydroxyl groups(More)
Sentinel lymphadenectomy is a useful way of assessing axillary status and obviating axillary dissection in patients with node-negative breast cancer. However, controversies remain concerning the optimal method to identify the sentinel lymph node (SLN) and detect micrometastases in this lymph node. We reviewed the literature concerning sentinel(More)
The flavonoid 5-glucosides, quercetin 5,4'-di-O-beta-D-glucopyranoside and quercetin 5,7,4'-tri-O-beta-D-glucopyranoside, together with the known quercetin 5-O-beta-D-glucopyranoside, were isolated from the cocoon shell of the silkworm, Bombyx mori. The structures were identified by spectroscopic analysis. These flavonoid glucosides were not present in(More)
In the present study, we investigated the effect of osmolality on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)). An osmotic gradient generated by NaCl with relatively apical hypertonicity (NaCl-absorption-direction) induced a large increase in the G(Na) associated with a small increase in(More)
Intact and fully O[emsp4 ]-sulfonated glycosaminoglycans (GAGs) including chondroitin sulfate, dermatan sulfate, hyaluronan, heparan sulfate and heparin were chemically de-O-sulfonated on their hexosamine C-6 position (6-O[emsp4 ]-desulfonation) using N,O[emsp4 ]-bis(trimethylsilyl) acetamide. 1H NMR spectroscopy and chemical compositional analysis showed(More)