Open AccessA unique DNA sequence of human enterotoxigenic Escherichia coli enterotoxin encoded by chromosomal DNA
Author(s) -
Imamura Seiji,
Kido Nobuo,
Kato Michio,
Kawase Hidetsugu,
Miyama Akio,
Tsuji Takao
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb10200.x
Subject(s) - biology , enterotoxin , plasmid , escherichia coli , enterotoxigenic escherichia coli , genetics , heat stable enterotoxin , chromosome , dna , microbiology and biotechnology , gene , circular bacterial chromosome
We detected Ent plasmids in 300 strains of human enterotoxigenic Escherichia coli , but one strain, E. coli 240‐3, had neither a small nor a large plasmid and encoded the heat‐labile enterotoxin (LTh(240‐3)) gene on its chromosome. DNA sequences showed that LTh(240‐3) differed by 12 and 14 base pairs from LT (LTh) and LT (LTp) from human H10407 and porcine EWD299 strains, respectively. In deduced precursor toxins, LTh(240‐3), LTh and LTp differed from LTh, LTp and LTh(240‐3) at nine, eight and eleven positions, respectively. These data suggest that although LTh(240‐3) encoded in the chromosome is antigenically similar to LTh, it cannot be grouped with LTh due to differences in its DNA and amino acids sequences.