Tracy Rosser

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Recent transposon mutagenesis studies with two enterohemorrhagic Escherichia coli (EHEC) strains, a sero- type O26:H- strain and a serotype O157:H7 strain, led to identification of a putative fimbrial operon that promotes colonization of young calves (1 to 2 weeks old). The distribution of the gene encoding the major fimbrial subunit present in O-island 61(More)
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a human pathogen that can cause gastrointestinal disease with potentially fatal consequences as a result of systemic Shiga toxin activity. Cattle are the main reservoir host of EHEC O157 and interventions need to be developed that prevent cattle colonization or limit shedding of the organism from this(More)
The sequence of two enterohaemorrhagic Escherichia coli (EHEC) O157:H7 strains reveals the possession of at least 16 fimbrial gene clusters, many of the chaperone/usher class. The first part of this study examined the distribution of these clusters in a selection of EHEC/EPEC (enteropathogenic E. coli) serotypes to determine if any were likely to be unique(More)
Non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 is the primary Shiga toxin-producing E. coli (STEC) serotype associated with human infection. Since 1988, sorbitol-fermenting (SF) STEC O157:NM strains have emerged and have been associated with a higher incidence of progression to hemolytic-uremic syndrome (HUS) than NSF STEC O157:H7. This study(More)
Escherichia coli O26 and O157 have similar overall prevalences in cattle in Scotland, but in humans, Shiga toxin-producing E. coli O26 infections are fewer and clinically less severe than E. coli O157 infections. To investigate this discrepancy, we genotyped E. coli O26 isolates from cattle and humans in Scotland and continental Europe. The genetic(More)
Three fluorescein-labeled lectins were shown to bind differentially to cell surfaces in different epithelial layers of rat oral mucosa regardless of the age or the site of origin of the tissue. Griffonia simplicifolia (GS-1-B4), specific for alpha-D-galactosyl end groups, labeled basal cells only; Ulex europeus (Ulex 1) specific for alpha-L-fucosyl groups(More)
Oral epithelial atypia and foci of acantholytic dyskeratosis (FAD) were investigated in 54 rats treated with the carcinogen 0.5% (w/v) 4-nitroquinoline-N-oxide in propylene glycol and in 18 rats treated with propylene glycol only. The palate of each animal was painted 3 times weekly for up to 9 months and rats were killed at monthly intervals. A gradual(More)
Ulex europeus (Ulex 1) has been used to study the expression of cell surface alpha-L-fucose on oral epithelial cells of normal human mucosa, white lesions and carcinomas. In normal tissue and in 11 of 12 specimens of non-specific keratoses (leukoplakia), Ulex 1 stained epithelial spinous cells only. In 16 specimens of oral lichen planus, Ulex 1 labelled(More)
Major histocompatibility complex (MHC) class I antigenic expression was examined on epithelial cell surfaces in normal oral mucosa, non-specific oral keratoses, dysplastic epithelium adjacent to carcinomas and in invasive tumour islands of squamous cell carcinomas, using antibodies to HLA-A,B,C shared determinant antigen and beta 2 microglobulin (beta 2m).(More)
Cell surface glycoconjugates were investigated in a rat model of oral chemical carcinogenesis. The lectins Griffonia simplicifolia (GS-I-B4; specific for alpha-D-galactosyl end groups) and Ulex europeus (UEA-I; specific for alpha-L-fucosyl groups) were examined microspectrofluorimetrically in the oral epithelium of rats painted with the carcinogen(More)