Masahiro Tomita
Terumo
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Publication
Featured researches published by Masahiro Tomita.
Nature Biotechnology | 2003
Masahiro Tomita; Hiroto Munetsuna; Tsutomu Sato; Takahiro Adachi; Rika Hino; Masahiro Hayashi; Katsuhiko Shimizu; Namiko Nakamura; Toshiki Tamura; Katsutoshi Yoshizato
We describe the generation of transgenic silkworms that produce cocoons containing recombinant human collagen. A fusion cDNA was constructed encoding a protein that incorporated a human type III procollagen mini-chain with C-propeptide deleted, a fibroin light chain (L-chain), and an enhanced green fluorescent protein (EGFP). This cDNA was ligated downstream of the fibroin L-chain promoter and inserted into a piggyBac vector. Silkworm eggs were injected with the vectors, producing worms displaying EGFP fluorescence in their silk glands. The cocoons emitted EGFP fluorescence, indicating that the promoter and fibroin L-chain cDNAs directed the synthesized products to be secreted into cocoons. The presence of fusion proteins in cocoons was demonstrated by immunoblotting, collagenase-sensitivity tests, and amino acid sequencing. The fusion proteins from cocoons were purified to a single electrophoretic band. This study demonstrates the viability of transgenic silkworms as a tool for producing useful proteins in bulk.
Biochimica et Biophysica Acta | 2001
Masahiro Hayashi; Masahiro Tomita; Katsutoshi Yoshizato
Collagen has been utilized as a natural biomaterial because of its high biocompatibility, adhesiveness to cells and tissues, and biodegradability. The present study developed a recombinant technology to confer a mitogenic activity on type III collagen by fusing it to epidermal growth factor (EGF) at the collagens N-terminus. The chimeric protein of EGF-collagen was synthesized in insect cells by the baculovirus-insect cell expression system. The fusion protein was shown to hold the triple helical conformation of collagen and the mitogenic activity of EGF. It was also demonstrated that the chimeric protein can be immobilized on tissue culture dishes as a fibrous form and in collagen fibrils without abolishing the original mitogenic activity of EGF. This fusion protein can be utilized as a biocompatible, biodegradable, and adhesive fibrous mitogen for a variety of purposes in the area of tissue engineering.
Parasitology Research | 1999
Koichi Koyama; Hidekazu Tamauchi; Masahiro Tomita; Takashi Kitajima; Yoichi Ito
Abstract Immune responses in resistant BALB/c mice infected with the murine nematode parasite Trichuris muris were examined. Following the establishment of infection, worm burdens of T. muris were expelled by BALB/c mice by day 21 postinfection (p.i.). Specific immunoglobulin G1 (IgG1) antibodies to T. muris excretory/secretory (E/S) antigens were detected in sera from infected mice, though specific IgG2a antibodies were not observed during infection. Ig-producing cells increased in the mesenteric lymph nodes (MLN) of infected mice on days 7, 14, and 21 p.i., with the greatest increase in numbers of IgG- and IgA-producing cells occurring on day 14. Marked increases in the relative percentages of B220+ and surface Ig+ (sIg+) cells were observed in the MLN of infected mice on days 14 and 21 p.i. Furthermore, cellular expansion of the MLN in infected mice resulted in an increase in the absolute numbers of B220+ and sIg+ cells. The levels of interleukin 2 (IL-2), IL-4, and interferon-γ (IFN-γ) detected in the supernatants from concanavalin A-stimulated MLN cells of infected mice were higher than those found in normal mice. Consequently, the expulsion of T. muris in resistant BALB/c mice was concomitant with cytokine production and B-cell activation in the MLN of infected mice. These results suggest the involvement of B-cell responses in protective immunity to T. muris infection.
Biochimica et Biophysica Acta | 1996
Morimichi Mizuno; Takashi Kitafima; Masahiro Tomita; Yoshinori Kuboki
In this study, we purified C-terminal propeptide of type I collagen (PICP) from the conditioned medium of osteoblastic MC3T3-E1 cells by chromatographic and Agarose gel extraction procedures. PICP was confirmed to be present in bone by Western blotting using a specific antibody, and was proved to be synthesized by osteoblasts with metabolic labeling. PICP promoted cell-attachment of osteoblastic MC3T3-E1 cells. We conclude that PICP is synthesized by osteoblasts and stored in bone, and that it plays a role in the maintenance of bone cells on bone matrix.
Biotechnology and Bioengineering | 2004
Masafumi Yamamoto; Masafumi Yamao; Hiroshi Nishiyama; Shinya Sugihara; Sumiharu Nagaoka; Masahiro Tomita; Katsutoshi Yoshizato; Toshiki Tamura; Hajime Mori
Journal of Biochemistry | 1997
Masahiro Tomita; Takashi Kitajima; Katsutoshi Yoshizato
Journal of Biochemistry | 1999
Masahiro Tomita; Katsutoshi Yoshizato; Takashi Ritajima
Archive | 2001
Katsutoshi Yoshizato; Masahiro Tomita; Tsutomu Satou; Hajime Mori; Toshiki Tamura; Takahiro Adachi; Hiroto Munetsuna
Archive | 2005
Masahiro Tomita; Katsuhiko Shimizu; Shingo Ogawa; Rika Hino; Masashi Iizuka; Takahiro Adachi; Katsutoshi Yoshizato
Archive | 2005
Masahiro Tomita; Katsuhiko Shimizu; Shingo Ogawa; Rika Hino; Masashi Iizuka; Takahiro Adachi; Katsutoshi Yoshizato