title: Construction of "Toxin Complex" in a Mutant Serotype C Strain of Clostridium botulinum Harboring a Defective Neurotoxin Gene.
abstract: A non-toxigenic mutant of the toxigenic serotype C Clostridium botulinum strain Stockholm (C-St), C-N71, does not produce the botulinum neurotoxin (BoNT). However, the original strain C-St produces botulinum toxin complex, in which BoNT is associated with non-toxic non-hemagglutinin (NTNHA) and three hemagglutinin proteins (HA-70, HA-33, and HA-17). Therefore, in this study, we aimed to elucidate the effects of bont gene knockout on the formation of the "toxin complex." Nucleotide sequence analysis revealed that a premature stop codon was introduced in the bont gene, whereas other genes were not affected by this mutation. Moreover, we successfully purified the "toxin complex" produced by C-N71. The "toxin complex" was identified as a mixture of NTNHA/HA-70/HA-17/HA-33 complexes with intact NTNHA or C-terminally truncated NTNHA, without BoNT. These results indicated that knockout of the bont gene does not affect the formation of the "toxin complex." Since the botulinum toxin complex has been shown to play an important role in oral toxin transport in the human and animal body, a non-neurotoxic "toxin complex" of C-N71 may be valuable for the development of an oral drug delivery system.
authors: Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan. ts200588@nodai.ac.jp.
authors: Tomonori
authors: T
authors: Suzuki
authors: Tokyo International Clinic, 4-18-19 Takanawa, Minato-ku, Tokyo, 108-0074, Japan.
authors: Thomas
authors: T
authors: Nagano
authors: Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, 099-2493, Japan.
authors: Koichi
authors: K
authors: Niwa
authors: Department of Applied Biology and Chemistry, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
authors: Masataka
authors: M
authors: Uchino
authors: Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
authors: Motohiro
authors: M
authors: Tomizawa
authors: Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, 099-2493, Japan.
authors: Yoshimasa
authors: Y
authors: Sagane
authors: Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, 099-2493, Japan.
authors: Toshihiro
authors: T
authors: Watanabe
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001905:Botulinum Toxins / Q000235:genetics* / Q000378:metabolism; D001906:Botulism / Q000382:microbiology; D003014:Clostridium botulinum / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017384:Sequence Deletion
chemical_list: D001426:Bacterial Proteins; D001905:Botulinum Toxins