Alex J Bolton

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Burkholderia pseudomallei and Burkholderia mallei are pathogens responsible for disease in both humans and animals. Burkholderia thailandensis, while phylogenetically similar, is considered avirulent in comparison. These three species exhibit phosphatase activity when grown on media containing chromogenic substrates such as 5-bromo-4-chloro-3-indolyl(More)
The mig gene of Streptococcus dysgalactiae, a major bovine mastitis pathogen, encodes two plasma protein-binding receptors, alpha2-macroglobulin (alpha2-M) and immunoglobulin G (IgG). In this study, the mig gene from one S. dysgalactiae isolate was cloned and expressed in Escherichia coli. The IgG receptor region encoded by mig was conserved in 16 S.(More)
Quantitative experiments on the interaction of Salmonella choleraesuis and Salmonella dublin with porcine and bovine intestinal epithelia yielded no evidence to suggest that host restriction of S. choleraesuis and S. dublin for pigs and calves respectively could be explained in terms of the patterns of intestinal invasion observed in ligated ileal loops in(More)
Ten recent clinical isolates of Salmonella serotype Typhimurium from man that were tested for their invasiveness in rabbit ileal explants in vitro, were compared with Typhimurium strain TML, a well-characterised invasive strain isolated from a case of human gastro-enteritis. Nine of the 10 strains showed invasiveness that was comparable to that of strain(More)
Patterns of invasiveness of Salmonella serotypes Typhimurium, Choleraesuis and Dublin in Caco-2 cells (without centrifugation) were compared with previously published studies of the rabbit ileal invasion assay (RIIA) and (where relevant) a HEp-2 cell invasion assay. Optimal conditions for the use of Caco-2 cell monolayers in bacterial invasion assays were(More)
A gene locus abp was identified immediately upstream of the CAMP factor gene cfu in Streptococcus uberis. An open reading frame capable of coding for a 277-residue protein was identified. On the basis of sequence characteristics, the abp gene product is potentially a polar amino acid and opine binding component of an ATP-binding cassette type (ABC-type)(More)
Salmonella Typhimurium strain GM3, known to be histotoxic for explants of terminal rabbit ileum in vitro, produces similar lesions in vitro when sterile filtrates, obtained from live organisms after interaction with gut explants in vitro, are used and when rabbit ligated ileal loops are challenged with live organisms. Epithelial damage occurs rapidly,(More)
The outer membrane protein OmpX of Enterobacter cloacae shows high amino acid homology with virulence proteins PagC and Rck from Salmonella typhimurium and with Ail from Yersinia enterocolitica. Here we demonstrate a role for OmpX in the invasion of rabbit ileal tissue by E. cloacae. An organ culture system was used for maintenance of rabbit gut tissue(More)
TnphoA transposon insertion mutants of phoN-negative derivatives of Salmonella typhimurium TML (of human gastroenteritic origin) were selected by growing mutagenized recipient bacteria under a variety of growth conditions. Ninety-seven individual mutants, which expressed alkaline phosphatase, were collected and tested for their ability to invade HEp-2(More)
Virulence determinants are inclined to be located on the bacterial surface or secreted into the milieu where they can interact with the host. A system that isolates defined mutations in secreted bacterial products is an invaluable tool for identifying virulence genes. One such system is the phoA gene-fusion approach that takes advantage of the fact that the(More)