shiga-like toxin converting phage of enterohemorrhagic escherichia coli strain 933.production of shiga-like toxin (slt) by enterohemorrhagic escherichia coli (ehec) is controlled by phage conversion, and specific phages carry either the slt-i or slt-ii operon. ehec strain 933 produces both slt-i and slt-ii. previous studies demonstrated that the vast majority of phages recovered from strain 993 have hexagonal heads with short tails and encode slt-ii. however, conflicting results were obtained concerning the properties of slt-i converting phages from strain 933. the present stu ...19892671581
cloning of genes for production of escherichia coli shiga-like toxin type ii.genes controlling production of shiga-like toxin type ii (slt-ii) in escherichia coli were cloned from the slt-ii-converting bacteriophage 933w and compared with the shiga-like toxin type i (slt-i) genes previously isolated and described from phage 933j. subcloning analysis identified a region within the 4.9-kilobase ecori fragment of phage 933w that was associated with slt-ii production. experiments with e. coli minicells containing these subclones demonstrated that the 4.9-kilobase ecori fragm ...19872822579
cloning of shiga-like toxin structural genes from a toxin converting phage of escherichia coli.the genes controlling high-level production of shiga-like toxin (slt) in escherichia coli were cloned from the slt converting phage 933j. this phage was isolated from a strain of e. coli that caused a foodborne outbreak of hemorrhagic colitis. the genes that convert normal e. coli to organisms producing high levels of toxin were cloned into the plasmid pbr328 and expressed in e. coli hb101. dna restriction mapping, subcloning, examination of the cloned gene products by minicell analysis, neutral ...19852994228
effects of iron and temperature on shiga-like toxin i production by escherichia coli.iron is known to depress shiga toxin production by shigella dysenteriae 1, and temperature has been shown to regulate several genes required for shigella invasiveness. in this study, the influence of iron and temperature on regulation of a highly related toxin, shiga-like toxin i (slt-i) of enterohemorrhagic escherichia coli, was examined in strains lysogenic for the toxin-converting coliphage 933j and in strains carrying the cloned slt-i genes on a high-copy-number plasmid vector. for compariso ...19883121508
nucleotide sequence analysis of the structural genes for shiga-like toxin i encoded by bacteriophage 933j from escherichia coli.a nucleotide sequence analysis was performed on the shiga-like toxin i genes previously cloned from the escherichia coli bacteriophage 933j. two structural genes designated slt-i a and slt-i b were found to be oriented on a single transcriptional unit with slt-i a preceding slt-i b. a 12 base pair gap separated the in-phase open reading frames of slt-i a and slt-i b. putative ribosome binding sites were identified 5' to both the slt-i a and slt-i b genes. translation of the slt-i nucleotide sequ ...19873333796
two toxin-converting phages from escherichia coli o157:h7 strain 933 encode antigenically distinct toxins with similar biologic activities.escherichia coli o157:h7 strain 933 contains two distinct toxin-converting phages (933j and 933w). the biologic activities and antigenic relationship between the toxins produced by 933j and 933w lysogens of e. coli k-12, as well as the homology of the genes that encode the two toxins, were examined in this study. the 933j and 933w toxins, like shiga toxin produced by shigella dysenteriae type 1, were cytotoxic for the same cell lines, caused paralysis and death in mice, and caused fluid accumula ...19863522426
heterogeneity of the amino-acid sequences of escherichia coli shiga-like toxin type-i operons.pcr was used to amplify approx. 1470-bp segments of dna containing complete shiga-like toxin type i (slti) operons from escherichia coli strains belonging to serotypes o48:h21, o111:h- and ox3:h8. these fragments were cloned and dna sequence analysis identified several variations, as compared with published slti sequences. all three slti genes analysed were more closely related to shiga toxin-encoding genes (sht) of shigella dysenteriae type 1, than to previously published e. coli phage-encoded ...19957883188
identification, characterization, and distribution of a shiga toxin 1 gene variant (stx(1c)) in escherichia coli strains isolated from using sequence analysis of shiga toxin 1 (stx 1) genes from human and ovine stx-producing escherichia coli (stec) strains, we identified an stx1 variant in stec of human origin that was identical to the stx1 variant from ovine stec, but demonstrated only 97.1 and 96.6% amino acid sequence identity in its a and b subunits, respectively, to the stx1 encoded by bacteriophage 933j. we designated this variant "stx1c" and developed stxb(1) restriction fragment length polymorphism and stx(1c)-specif ...200211923370
identification and characterization of a new variant of shiga toxin 1 in escherichia coli ont:h19 of bovine origin.a new variant of shiga toxin 1 (stx1), designated stx1d, which deviates considerably more than any other known variant from stx1 encoded by phage 933j, was identified in an escherichia coli strain, ont:h19, isolated from bovine feces. the complete stx(1) gene of this strain was amplified and sequenced. nucleotide sequence homology with stx(1) from phage 933j was only 91%, resulting in the substitution of 20 amino acids in the a subunit and 7 amino acids in the b subunit of the protein. cell cult ...200312734256
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