PCR for detection of cdt-III and the relative frequencies of cytolethal distending toxin variant-producing Escherichia coli isolates from humans and cattle - PubMed (original) (raw)

FIG. 1.

Sensitivities of _cdt_-specific primers. (A) Different concentrations of boiled cell preparations. The isolates in lanes 1 to 6 were amplified with _cdt-I_-specific primers, the isolates in lanes 7 to 12 were amplified with _cdt-II_-specific primers, and the isolates in lanes 14 to 19 were amplified with _cdt-III_-specific primers. The numbers of boiled bacterial cells serving as templates for each lane were as follows: lanes 1, 7, and 14, 1.25 × 105; lanes 2, 8, and 15, 1.25 × 104; lanes 3, 9, and 16, 1.25 × 103; lanes 4, 10, and 17, 1.25 × 102; lanes 5, 11, and 18, 12.5; lanes 6, 12, and 19, 1.25. Lane 13, 100-bp ladder. (B) Different concentrations of extracted DNA preparations. The isolates in lanes 2 to 7 were amplified with _cdt-I_-specific primers, the isolates in lanes 8 to 13 were amplified with _cdt-II_-specific primers, and the isolates in lanes 14 to 19 were amplified with _cdt-III_-specific primers. The amounts of DNA in each lane were as follows: lanes 2, 8, and 14, 500 ng; lanes 3, 9, and 15, 50 ng; lanes 4, 10, and 16, 5 ng; lanes 5, 11, and 17, 0.5 ng; lanes 6, 12, and 18, 0.05 ng. Lanes 7, 13, and 19, negative controls containing water instead of the DNA template used for each PCR; lanes 1 and 20, 100-bp ladders.