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Dive into the research topics where Masahiro Murata is active.

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Featured researches published by Masahiro Murata.


Biochemical and Biophysical Research Communications | 1989

Identification of the two types of specific receptor for activin/EDF expressed on Friend leukemia and embryonal carcinoma cells.

Sigeru Kondo; Makoto Hashimoto; Yuzuru Etoh; Masahiro Murata; Hiroshiro Shibai; Masami Muramatsu

Activin and inhibin are polypeptide factors which control the release of follicle stimulating hormone(FSH) from pituitary cells. The recent finding that erythroid differentiation factor(EDF) is identical to activin showed the multifunctional feature of this protein. To identify the specific receptor for activin, the binding of 125I-labeled activinA was investigated for a number of culture cell lines. Friends leukemia cell, which can be differentiated by activin, and embryonal carcinoma(EC) cells(PCC3, P19 and F9), were found to express 3500-20,000 per cell of activin receptors. Scatchard plot analysis of the binding data shows that the receptors on those cells could be divided into two groups with different Kd values. The Kd values of high and low affinity receptors are 0.15-0.4 nM and 1.5-3.0 nM respectively. The proportion of the number of the high and low affinity receptors was varied in each cell. Inhibin was able to compete for activin binding to both types of receptors, although the binding affinity was about 50-200 fold lower than that of activinA. Transforming growth factor-beta had no binding ability to the activin receptors.


Biochemical and Biophysical Research Communications | 1988

Expression of erythroid differentiation factor (EDF) in Chinese hamster ovary cells

Masahiro Murata; Kazuya Onomichi; Yuzuru Eto; Hiroshiro Shibai; Masami Muramatsu

Plasmid DNA containing EDF subunit cDNA and mouse dihydrofolate reductase (DHFR) cDNA was transfected into CHO DHFR- cells by the calcium-phosphate method. DHFR positive transformants secreted recombinant EDF (r-EDF) constitutively in an active form and accumulated it in the conditioned medium. Furthermore, cells which were resistant to methotrexate (MTX : 0.5 microM) secreted r-EDF up to 1 microgram/ml. r-EDF was identical to natural EDF (n-EDF) produced by human acute monocytic leukemia cell line, THP-1, as regards its dimeric structure and a biological activity.


Journal of Fermentation Technology | 1988

Large-Scale Production of Erythroid Differentiation Factor (EDF) by Gene-Engineered Chinese Hamster Ovary (CHO) Cells in Suspension Culture

Masahiro Murata; Yuzuru Eto; Hiroshiro Shibai

Abstract From Chinese hamster ovary (CHO) cells which were producing Erythroid Differentiation Factor (EDF) in a culture medium, anchorage-independent cells, named as CHO-SPN, were produced by repeated cultivating in a suspension system. The growth time and maximum cell density of the CHO-SPN cells were 48 h and 7.8×10 5 viable cells/ml. CHO-SPN cells accumulated 8,000 units/ml (corresponding to 4 mg/ml) of EDF in 4d. After 20 cycles of culture, CHO-SPN cells still possessed the same EDF productivity and the same growth kinetics. Furthermore, in an appropriate dissolved oxygen concentration and pH controlled culture system, the growth time and cell density became 24 h and 1×10 6 viable cells/ml. The critical level of dissolved oxygen for cell growth was 0.015 atm. The maximum oxygen demand was 3.3×10 −9 mole of O 2 /ml/min. Fetal bovine serum (FBS) was indispensable for cell growth. However, a FBS-free medium (ASF201) was available for maintenance of the CHO-SPN cells, and EDF production occurred in the same medium.


International Immunopharmacology | 2005

Development and validation of a novel IL-10 deficient cell transfer model for colitis.

Yuka Ikenoue; Tomoyuki Tagami; Masahiro Murata


Archive | 2003

NEW PHENYLALANINE DERIVATIVES

Nobuyasu Suzuki; Toshihiko Yoshimura; Hiroyuki Izawa; Kazuyuki Sagi; Shingo Makino; Eiji Nakanishi; Masahiro Murata; Takashi Tsuji


Archive | 2004

Phenylpropionic acid derivatives

Akira Chiba; Kazuyuki Sagi; Toshihiko Yoshimura; Tatsuya Okuzumi; Hiroyuki Izawa; Masahiro Murata


Archive | 1999

Gliotoxin derivatives and anticancer agent comprising the same

Chika Mukai; Koji Ohsumi; Ryusuke Nakagawa; Toshihiko Yoshimura; Yuka Kanayama; Yoko Obayashi; Kenichi Kaida; Yasuyo Suga; Masahiro Murata


Agricultural and biological chemistry | 1988

Structural and biological identity of recombinant EDF (erythroid differentiation factor) with natural EDF

Tomoko Tsuji; Masahiro Murata; Kazuya Onomichi; Yuzuru Eto; Hiroshiro Shibai


Archive | 2006

Method for estimating immunostimulant activity of a polysaccharide

Tetsuya Suga; Yasuyo Suga; Masahiro Murata


Archive | 1997

Novel antitumor compounds and process for producing the same

Yoko Obayashi; Toshihiko Yoshimura; Yuka Ikenoue; Ryosuke Fudo; Masahiro Murata; Toshihiko Ando

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