A "successful allele" at Campylobacter jejuni contingency locus Cj0170 regulates motility; "successful alleles" at locus Cj0045 are strongly associated with mouse colonization.

Campylobacter jejuni is an important foodborne pathogen of humans and its primary reservoir is the gastrointestinal (GI) tract of chickens. Our previous studies demonstrated that phase variation to specific "successful alleles" at C. jejuni contingency loci Cj0045 (successful alleles carry 9G or 10G homopolymeric tracts) and Cj0170 (successful allele carries a 10G homopolymeric tract) in C. jejuni populations is strongly associated with colonization and enteritis in C57BL/6 IL-10 deficient mice. In the current study, we strengthened the association between locus Cj0170, Cj0045, and mouse colonization. We generated 8 independent strains derived from C. jejuni 11168 strain KanR4 that carried a Cj0170 gene disruption and these were all non motile. Two randomly chosen strains with the Cj0170 gene disruption (DM0170-2 and DM0170-6) were gavaged into mice. DM0170-2 and DM0170-6 failed to colonize mice while the control strain that carried a "successful"Cj0170 10G allele was motile and did colonize mice. In parallel studies, when we inoculated C. jejuni strain 33292 into mice, the "unsuccessful"Cj0045 11G allele experienced phase variation to "successful" 9G and 10G alleles in 2 independent experiments prior to d4 post inoculation in mice while the "successful" 9G allele in the control strain remained stable through d21 post inoculation or shifted to other successful alleles. These data confirm that locus Cj0170 regulates motility in C. jejuni strain KanR4 and is a virulence factor in the mouse model. The data also support a possible role of locus Cj0045 as a virulence factor in strain 33292 in infection of mice.

Cardiac tissue Doppler and tissue velocity imaging in anesthetized New Zealand white rabbits.

New Zealand white rabbits are commonly used in cardiovascular research. Complete echocardiographic examination of the heart includes the evaluation of tissue Doppler (TDI) parameters, yet normal data are unavailable for rabbits. In addition, tissue velocity imaging (TV) is a potentially useful measure of myocardial function that has not yet been applied to rabbits. Anesthetized New Zealand white rabbits (n = 31) underwent echocardiography to establish the feasibility of performing TDI and TV and establishing corresponding reference values. Standard 2D, M-mode, and Doppler measurements were obtained in all rabbits and showed values comparable to previously published data. Interpretable TDI images were obtained in all 31 rabbits and TV in 24 of 31 rabbits. The values obtained were similar to those seen in healthy cats and are comparable to the values found in adult humans. TDI and TV can easily be added to standard echocardiographic evaluation in rabbits. The values from the current study, obtained in normal rabbits, can be used as reference values to improve characterization of cardiac disease in this species.