OBJECTIVE: Cloning of ipaJ gene from Salmonella pullorum C79-13, and identification of expressed IpaJ protein as an immunogen of the pathogen. METHODS: With suppression subtractive hybridization (SSH) between Salmonella pullorum strain C79-13 (tester) and Salmonella enteritidis strain 50041 (driver), three subtracted fragments PEA3, PE31 and PE44 showed high homology with ipaJ in plasmid pSFD10 of Salmonella choleraesuis C500. The three subtracted sequences were spliced together into the whole sequence of ipaJ in Salmonella pullorum. Then the ipaJ gene was amplified from Salmonella pullorum by polymerase chain reaction (PCR) and cloned into prokaryotic expressive vector pET-30a(+). Western-blot was used to identify it as an immunogen. The distribution of the gene was also detected in Salmonella pullorum isolates. RESULTS: The ipaJ gene cloned from Salmonella pullorum was 840 bp, and the expressed fusion protein was 37 kDa. Specific reaction was found between Salmonella pullorum positive serum and expressed protein by Western-blot assay, confirming its identification as an immunogen of Salmonella pullorum. The PCR results showed that the gene exists in all Salmonella pullorum strains. CONCLUSION: The ipaJ gene from Salmonella pullorum was first reported and cloned, and the expressed IpaJ protein was confirmed as an immunogen of Salmonella pullorum.
OBJECTIVE: Cloning of ipaJ gene from Salmonella pullorum C79-13, and identification of expressed IpaJ protein as an immunogen of the pathogen. METHODS: With suppression subtractive hybridization (SSH) between Salmonella pullorum strain C79-13 (tester) and Salmonella enteritidis strain 50041 (driver), three subtracted fragments PEA3, PE31 and PE44 showed high homology with ipaJ in plasmid pSFD10 of Salmonella choleraesuis C500. The three subtracted sequences were spliced together into the whole sequence of ipaJ in Salmonella pullorum. Then the ipaJ gene was amplified from Salmonella pullorum by polymerase chain reaction (PCR) and cloned into prokaryotic expressive vector pET-30a(+). Western-blot was used to identify it as an immunogen. The distribution of the gene was also detected in Salmonella pullorum isolates. RESULTS: The ipaJ gene cloned from Salmonella pullorum was 840 bp, and the expressed fusion protein was 37 kDa. Specific reaction was found between Salmonella pullorum positive serum and expressed protein by Western-blot assay, confirming its identification as an immunogen of Salmonella pullorum. The PCR results showed that the gene exists in all Salmonella pullorum strains. CONCLUSION: The ipaJ gene from Salmonella pullorum was first reported and cloned, and the expressed IpaJ protein was confirmed as an immunogen of Salmonella pullorum.