JaLCDOI 10.18926/47026
FullText URL mfe_36_2_061_066.pdf
Author Yamagiwa, Masashi| Namba, Akitoshi| Akao, Tetsuyuki| Mizuki, Eiichi| Ohba, Michio| Sakai, Hiroshi|
Abstract The crystal proteins produced by Bacillus thuringiensis subsp, israelensis (Bti) and subsp. coreanensis A1519 strain were examined for the cytotoxicity against MOLT-4 and HeLa cells by MTT assay and LDH assay, The A1519 crystal proteins processed by proteinase K exhibited the specific cell-killing activity toward MOLT-4 with little damage to the cell membrane, On the other hand, the Bti crystal proteins processed by proteinase K caused the substantial damage to the cell membrane of both MOLT-4 and HeLa, leading to the cell lysis. The non-digested crystal proteins of both strains exhibited no cytotoxicity, These data suggested that while the Bti crystal proteins caused the colloid-osmotic swelling and cell lysis of MOLT-4 and HeLa, the proteinase K-digested A1519 crystal proteins induced the specific cell death of MOLT-4 through a mechanism other than that of Bti.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2002-03
Volume volume36
Issue issue2
Start Page 61
End Page 66
ISSN 0475-0071
language 英語
File Version publisher
NAID 80015582224
JaLCDOI 10.18926/46981
FullText URL mfe_37_2_067_072.pdf
Author Yamagiwa, Masashi| Sakai, Hiroshi|
Abstract An active form of Cry4A is a heterodimer of the 20- and 45-kDa fragments that are derived from the 130-kDa Cry4A protoxin. To investigate the function of these two fragments, several deletion mutants were constructed and expressed in E.coli as the GST (glutathione-S-transferase) fusion proteins. The results of the bioassay against Culex pipiens larvae showed that the interaction of two fragments of Cry4A was necessary for the toxicity, and that the C-terminal 67 amino acids of the 20-kDa fragment corresponding to the helices α4 and α5 were involved in determining the insecticidal activity. Surprisingly the lack of helix α5 did not affect the toxicity to C. pipiens, suggesting that the role of helix α5 of Cry4A was different from that postulated in the case of Cry4A toxins.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2003-03
Volume volume37
Issue issue2
Start Page 67
End Page 72
ISSN 0475-0071
language 英語
File Version publisher
NAID 80016019143
JaLCDOI 10.18926/46956
FullText URL mfe_38_1-2_097_100.pdf
Author Yamagiwa, Masashi| Hirao, Taichi| Kiyomi, Masaaki| Akao, Tetsuyuki| Mizuki, Eiichi| Ohba, Michio| Sakai, Hiroshi|
Abstract Bacillus thuringiensis subsp. coreanensis A2316 is a newly isolated strain from Yonakunijima Island in Japan. It produces the proteinaceous inclusion body (crystal) which has no insecticidal and hemolytic activities. When the crystal proteins were digested by proteinase K, they exhibited the strong cytotoxicity against human leukemic T cell, MOLT-4. The proteinase K-digested A2316 crystal proteins have little damage upon the cell membrane of MOLT-4, suggesting that the cell death of MOLT-4 was induced through a mechanism other than the colloid-osmotic swelling and cell lysis as caused by hitherto known B. thuringiensis crystal proteins. The 29-kDa polypeptide proved to be an active component of the proteinase K-digested A2316 crystal proteins. EC(50) of the purified 29-kDa polypeptide was 0.0579 μg/ml. The N-terminal amino acid sequence of the 29-kDa polypeptide was identical with that of p29 produced by B. thuringiensis A1519 strain and shared no significant homology with all the known proteins, suggesting that this polypeptide belong to a new family of B. thuringiensis crystal proteins.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2004-03
Volume volume38
Issue issue1-2
Start Page 97
End Page 100
ISSN 0475-0071
language 英語
File Version publisher
NAID 80017001823
Author Sakai, Hiroshi| Yamagiwa, Masashi|
Published Date 2003-08
Publication Title 環境制御
Volume volume25
Content Type Departmental Bulletin Paper
Author Yoshida, Hidenori| Ihoriya, Kazuo| Nagahana, Haruki| Nishihara, Masanobu| Hyodo, Tatsuo| Uchida, Toshiaki| Kimura, Masashi| Takeda, Kou| Fujii, Akinobu| Saito, Daiji| Tanatani, Setsuro| Kita, Toshimasa| Sakai, Hiroshi| Haraoka, Shoichi|
Published Date 1981-06-30
Publication Title 岡山医学会雑誌
Volume volume93
Issue issue5-6
Content Type Journal Article
JaLCDOI 10.18926/15366
FullText URL Mem_Fac_Eng_OU_35_147.pdf
Author Yamagiwa, Masashi| Sakai, Hiroshi|
Abstract The Cry4A toxin is a dipteran-specific insecticidal protein produced by Bacillus thuringiensis subsp. israelensis as a protoxin of 130 kDa. Its active form is a heterodimer of 20- and 45-kDa fragments which is generated by an interhelical cleavage of a 60-kDa intermediate at the position of Gln236 between α5 and α6 helices in domain I. On the other hand, Cry1Aa, which is also produced as a 130-kDa protoxin but toxic to lepidopteran larvae, was processed into the active 60-kDa fragment with no additional cleavage. To investigate the role of the intramolecular cleavage of Cry4A for its insecticidal activity, the loop between α5 and α6 of Cry4A which includes the cleavage site was substituted for the corresponding region of Cry1Aa. The resulting mutant designated GST-60Loop was expressed as a GST-fusion protein. A difference of the processing profile was observed between GST-60 and GST-60Loop in the in vitro digestion assay by trypsin, and the insecticidal activity of GST-60Loop was two-fold lower than that of GST-60. These results suggested that the interhelical cleavage of Cry4A promoted the toxicity against C. pipiens larvae.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 147
End Page 154
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307324