title: Characterization of the neurotoxin produced by isolates associated with avian botulism.
abstract: Several varieties of birds are affected by type C botulism. We conducted neutralization tests of culture supernatants of isolates from cases of avian botulism. Whereas the toxin produced by isolates derived from mammalian botulism was neutralized only with type C antitoxin, the toxins of all isolates related to avian botulism were neutralized with both type C and D antitoxins. An analysis of nucleotide sequences with several strains revealed that the neurotoxin gene in the isolates from avian botulism comprises two thirds of the type C neurotoxin gene and one third of the type D neurotoxin gene. This indicates that the neurotoxin of avian isolates is a mosaic of type C and D neurotoxins. We prepared three sets of primers to differentiate the gene for the mosaic form from the conserved genes of type C and D neurotoxins. The results of polymerase chain reaction with these primers indicated that all avian botulism-related isolates and specimens possess the gene for the mosaic form of the neurotoxin. The toxins purified from avian and mammalian isolates exhibited the same degree of lethality in mice, but the former showed greater toxicity to chickens than the latter. These results indicate that the mosaic neurotoxin is probably a pathogenic agent causing some forms of avian botulism.
authors.affiliation: Department of Veterinary Science, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Takeda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tsukamoto
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kohda
authors.forename: Miki
authors.initials: M
authors.lastname: Matsui
authors.forename: Masafumi
authors.initials: M
authors.lastname: Mukamoto
authors.forename: Shunji
authors.initials: S
authors.lastname: Kozaki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001715:Bird Diseases / Q000382:microbiology*; D001905:Botulinum Toxins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity*; D001906:Botulism / Q000382:microbiology* / Q000662:veterinary*; D002645:Chickens; D003014:Clostridium botulinum / Q000737:chemistry* / Q000378:metabolism / Q000472:pathogenicity*; D007928:Lethal Dose 50; D051379:Mice; D009500:Neutralization Tests; D017386:Sequence Homology, Amino Acid
chemical_list: D001905:Botulinum Toxins