Search PubMed⌕ Search

Biomedical subjects

G W Jones

Publications and source records attributed to G W Jones.

At least 127 records · Page 7Linked to original sources
PubMed1975

An attempt to identify the intestinal receptor for the K88 adhesin by means of a haemagglutination inhibition test using glycoproteins and fractions from sow colostrum.

The K88 antigen of Escherichia coli specifically adheres to the piglet intestinal cell; a solution of this antigen agglutinates guinea-pig red cells at 4 degrees C. The latter reaction was used as a model of the former, using inhibition of haemagglutination as an index of specific combination with the K88 adhesin. Inhibition was found with mucous glycoproteins and chemical modification of their heterosaccharide residues by mild acid hydrolysis, periodate oxidation or the Smith degradation procedure suggested that the terminal beta-D-galactosyl structure in a heterosaccharide sidechain of a glycoprotein might combine specifically with the K88 adhesin and inhibit haemagglutination. One serum glycoprotein (fetuin), after exposure of its subterminal beta-D-galactosyl residue, also inhibited haemagglutination, but high inhibitory activity was exhibited by some submaxillary glycoproteins in which this structure was absent or not prominent. It was concluded that in some cases inhibition of haemagglutination by glycoprotein was non-specific. No inhibition was found using glycosaminoglycans, glycogen or any simple sugar or glycoside. Sow colostrum was inhibitory but this was associated mainly with its gamma-globulin fraction. Some inhibitory activity was traced to a colostral glycopeptide fraction of low molecular weight but the smaller colostral oligosaccharides were not inhibitory; the composition of these components in sow colostrum is reported.

Alpha-Globulins↗
PubMed1975

Adhesion of enteropathogenic Escherichia coli to pig intestinal brush borders: the existence of two pig phenotypes.

An in-vitro test that demonstrates adhesion of K88-positive Escherichia coli to brush borders prepared from the small intestine of the pig is described. K88-positive E. coli adhered to the brush borders from some pigs ("positive" pigs) but not others ("negative" pigs). The sires of the pigs tested could be placed into two groups, namely, those that sired only "positive" piglets, and those that sired a mixture of "positive" and "negative" piglets. The incidence of the two phenotypes in litters indicated that "positive" and "negative" piglets arose as a result of simple Mendelian inheritance. It is suggested that "negative" pigs could be bred and that they might have a natural resistance to neonatal infection with K88-positive E. coli.

Animals↗
PubMed1972

Role of the K88 antigen in the pathogenesis of neonatal diarrhea caused by Escherichia coli in piglets.

The role of the K88 antigen of Escherichia coli in neonatal diarrhea of piglets was studied by comparing a K88-positive strain with three K88-negative strains derived from the K88-positive strain. K88 antigen was produced by the K88-positive strain in the intestinal tract of gnotobiotic piglets, whereas K88-negative strains did not regain the ability to synthesize K88 antigen. Synthesis of the antigen conferred different colonization characteristics on the four strains; K88-positive bacteria adhered to the mucosa of the small intestine, whereas K88-negative bacteria did not attach and were distributed throughout the lumen. Adhesion of K88-positive bacteria to tissue from the small intestine of gnotobiotic piglets was demonstrated in vitro and was inhibited by antisera that contained K88 antibodies. Attachment did not occur with bacteria grown at 18 C. Adhesion of cell-free K88 antigen was also demonstrated. The K88-positive strain and one of the K88-negative strains were equally virulent in gnotobiotic piglets. In contrast, the K88-positive strain killed 50% of conventionally reared piglets, whereas the K88-negative strain killed only 3%. Adhesion of the K88-positive strain, but not of the K88-negative strain, to the mucosa of the small intestine was demonstrated. Our results show that K88 antigen is responsible for attachment of K88-positive bacteria to the wall of the small intestine, and that adhesion is essential for the virulence of K88-positive bacteria in conventionally reared piglets.

Agglutination Tests↗