Genetic analysis of K88-mediated adhesion of enterotoxigenic Escherichia coli

Kehoe, Michael; Sellwood, R.; Shipley, P L; Dougan, Gordon

doi:10.1038/291122a0

Cited by 74 publications

(61 citation statements)

References 23 publications

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“…The strong correlation between pili and S motility observed by Kaiser (15) suggests a function in cohesion, because the role of pili as attachment organelles has been demonstrated in a variety of pathogenic bacteria (2,9,17,21,23). M. xanthus pili about one cell length long were observed in a tuft at one of the cell poles (15).…”

Section: Discussionmentioning

confidence: 97%

Cell surface properties correlated with cohesion in Myxococcus xanthus

1988

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The gliding behavior of Myxococcus xanthus cells is controlled by two multigene systems, A and S, which encode information for adventurous and social behaviors, respectively. The S system can be genetically disrupted through mutation, such as a dsp mutation, or phenotypically disrupted by treating cells with the diazo dye Congo red (Arnold and Shimkets, J. Bacteriol. 170:5765-5770, 1988). One of the functions controlled by the S system is cell agglutination. Immediately after the induction of agglutination, wild-type cells begin to form aggregates, and within 30 min the cells are packed side-to-side in clumps containing thousands of cells. Changes in the cohesive properties of S+ cells are correlated with changes in the topology of the cell surface observed by electron microscopy. Two types of cell-associated appendages were observed on wild-type cells: thin filaments (ca. 5 nm in diameter), which have been called fimbriae or pili, at one cell pole, and thick, flaccid ifiaments (ca. 50 nm in diameter), referred to as fibrils, at both the sides and tips of cells. Cohesion was correlated with the secretion of the thick fibrils, which coat the cell surface and form an extracellular matrix in which the cells are interconnected. Several lines of evidence suggest that these thick fibrils are involved in cohesion. First, Dsp cells were unable to agglutinate or secrete this extracellular material. Second, wild-type cells which were treated with Congo red neither agglutinated nor secreted the extracellular fibrils. Finally, removal of the Congo red from wild-type cells restored cohesion and also restored production of the thick fibrils. Attempts to estimate the efficiency with which two cells cohered following collision suggested that under optimal conditions, one in three collisions resulted in stable contact. The collision efficiency decreased linearly as the cell density increased, suggesting a cell density-dependent regulation of cohesion. Some aspects of gliding behavior can be explained in terms of an inducer and an inhibitor of S motility.

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Section: Discussionmentioning

confidence: 97%

Cell surface properties correlated with cohesion in Myxococcus xanthus

1988

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“…The cosmid vector pHC79 (5) was used for cosmid cloning. The K88 gene probes were derived from pMKO05 (7). The K99 gene probes were derived from pFK99 (3).…”

Section: Methodsmentioning

confidence: 99%

Cloning of chromosomal DNA encoding the F41 adhesin of enterotoxigenic Escherichia coli and genetic homology between adhesins F41 and K88

Moseley¹,

Dougan²,

Schneider³

et al. 1986

J Bacteriol

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The genetic determinant for production of the adhesive antigen F41 was isolated from a porcine enterotoxigenic Escherichia coli strain by cosmid cloning. The cloned DNA included sequences homologous to those of hybridization probes prepared from the K88 adhesive antigen operon. Transposon insertions which inactivated F41 production mapped to the same region of DNA showing homology with the K88 genes, demonstrating the genetic relatedness of F41 and K88. Hybridization of a K88 gene probe to plasmid and total DNA from the porcine E. coli isolate from which the F41 gene was cloned indicated that F41 is chromosomally encoded by this strain. This observation was extended to other F41-producing animal isolates. A large number of animal E. coli isolates were examined with K88, F41, and K99 gene probes and for mannose-resistant hemagglutination of human group 0 erythrocytes and K88 and F41 antigen production. All K88 and F41 antigen producers possessed genetic homology with the K88 and F41 gene probes. Most, but not all, F41-producing strains possessed homology to the K99 gene probe, reflecting the previously observed association of F41 and K99 antigen production. In the strains examined, homology with the K99 gene probe was plasmid associated, whereas homology with the F41 gene probe was chromosomal. The K88 antigen-producing strains showed no homology with the K99 probe. A number of strains possessed homology with the K88 and F41 gene probes and were mannose-resistant hemaggiutination positive, but did not produce K88 or F41 antigens. This suggests that there are adhesins among animal isolates of E. coil which are genetically related to but antigenically distinct from K88 and F41.Enterotoxigenic Escherichia coli (ETEC) adhere to the epithelium of the small intestine of the host and produce enterotoxins which cause diarrhea. The bacterial proteins of fimbrial structure which cause adherence are called adhesins. Several antigenic types of ETEC adhesins which confer a degree of host species specificity have been described (4). Most ETEC adhesins agglutinate erythrocytes in the presence of mannose, providing a convenient assay for the presence of an adhesin. The hemagglutinating capacity of different adhesins varies with the species source of the erythrocytes. All ETEC adhesin genes which have been located are plasmid encoded (4).The F41 antigen is a recently described fimbrial adhesin of ETEC that are pathogenic for cattle and swine (2, 13). The F41 antigen was first recognized as a second mannoseresistant hemagglutinin produced by ETEC strains which also express the K99 adhesin (14). The F41 antigen is associated with K99-producing ETEC of serogroups 09 and 0101, but has not been reported among K99-producing strains of other serogroups (15). Recently, F41 production has been demonstrated in non-K99-producing strains of ETEC of serogroup 0101 isolated from piglets with diarrhea (15). These strains have been demonstrated to be fully virulent in experimental infections in piglets and calves (1,15,21). This suggests that F4...

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“…The effect of the faeF mutation could be fully restored by introduction of pMKO77 into the FaeF mutant. Plasmid pMKO77 contains the genes faeC-faeF of the K88ac operon (6).…”

Section: Resultsmentioning

confidence: 99%