The following temperature cycle was used for PCR: 95 °C for 2 min, followed by 30 cycles at 94 °C for 40 s, 52 °C for 30 s, and 72 °C for 1 min, with a final

extension at 72 °C for 5 min. To further characterize the distribution of the differential DNA sequences among the 15 A. pleuropneumoniae serotypes, we extracted the genomic DNA of the 16 reference strains using the AxyPrep Bacterial Genomic DNA Miniprep kit (Axygen) and used this DNA for PCR-based identification of the differential sequences in A. pleuropneumoniae serotypes. The genomic differences between the CVCC259 and CVCC261 strains were determined by RDA. The DP3 differential products were analyzed using neutral polyacrylamide gel NVP-BEZ235 research buy electrophoresis, and we detected sequences with sizes of approximately 100–400 bp (data not shown). The RDA products were cloned into the pGEM-T vector and sequenced. On the basis of the results of the blastn analysis and the annotation information in GenBank, eight differential

DNA sequences were identified in the CVCC259 strain and 11 differential DNA sequences were identified in the CVCC261 strain. Southern blotting analysis was performed to confirm whether the differential DNA sequences were derived from the chromosome of each tester. All the 19 differential sequences screened from each tester were able to hybridize with the genomic DNA probe of the tester, thereby yielding 19 blots with strongly positive hybridization. However, there were no hybridization selleck inhibitor blots in the experiment conducted using the 19 tester-specific DNA sequences and the genomic

DNA probe from each driver (Fig. 1). Genomic DNA from the CVCC259 and CVCC261 strains was used as the template for the PCR-based identification of differential DNA sequences. The electrophoresis results showed that all the 19 Southern-hybridization-positive genes were amplified when the genomic DNA of each tester was used as a template, but they were not amplified when the genomic DNA of Florfenicol each driver was used as a template (Fig. 2). The differential DNA sequences were identified using the genomic DNA from the 17 isolates as the template. All the eight differential DNA sequences of the CVCC259 strain were present in the nine isolates of serotype 1, but absent in the eight isolates of serotype 3. All the 11 differential DNA sequences of the CVCC261 strain were present in the eight isolates of serotype 3, but absent in the nine isolates of serotype 1 (data not shown). After confirming the genomic origin of the differential DNA sequences, the eight differential DNA sequences of the CVCC259 strain and the 11 differential DNA sequences of the CVCC261 strain were identified. The nucleotide similarities of these sequences were determined by searches in GenBank, the European Molecular Biology Laboratory database, and DNA databank of Japan. Although the complete genome of the A.