Anti-DNase I polyclonal antibody [HRp]

In the recent years, African swine fever has become the biggest animal health threat to the swine industry. To facilitate quick genetic analysis of its causative agent, the African swine fever virus (ASFV), we developed a simple and efficient method for next generation sequencing of the viral DNA. Execution of the protocol does not demand complicated virus purification steps, enrichment of the virus by ultracentrifugation or of the viral DNA by ASFV-specific PCRs, and minimizes the use of Sanger sequencing. Efficient DNA-se treatment, monitoring of sample preparation by qPCR, and whole genome amplification are the key elements of the method. Through detailed description of sequencing of the first Hungarian ASFV isolate (ASFV_HU_2018), we specify the sensitive steps and supply key reference numbers to assist reproducibility and to facilitate the successful use of the method for other ASFV researchers.

The survival ability of Salmonella enterica serovar Enteritidis in antibacterial egg white is an important factor leading to Salmonella outbreaks through eggs and egg products. In this study, the role of the gene yoaE, encoding an inner membrane protein, in the survival of Salmonella Enteritidis in egg white, and its transcriptional regulation by CpxR were investigated. Quantitative reverse transcription-PCR (RT-qPCR) results showed that the yoaE gene expression was upregulated 35-fold after exposure to egg white for 4 h compared to that in M9FeS medium, and the deletion of yoaE (Delta yoaE) dramatically decreased the survival rate of bacteria in egg white to less than 1% of the wild type (WT) and the complementary strain at both 37 and 20 degrees C, indicating that yoaE was essential for bacteria to survive in egg white. Furthermore, the Delta yoaE strain was sensitive to a 3-kDa ultrafiltration matrix of egg white because of its high pH and antimicrobial peptide components. Putative conserved binding sites for the envelope stress response regulator CpxR were found in the yoaE promoter region. In vivo, the RT-qPCR assay results showed that the upregulation of yoaE in a Delta cpxR strain in egg white was 1/5 that of the WT. In vitro, results from DNase I footprinting and electrophoretic mobility shift assays further demonstrated that CpxR could directly bind to the yoaE promoter region, and a specific CpxR binding sequence was identified. In conclusion, it was shown for the first time that CpxR positively regulated the transcription of yoaE, which was indispensable for survival of Salmonella Enteritidis in egg white. IMPORTANCE Salmonella enterica serovar Enteritidis is the predominant Salmonella serotype that causes human salmonellosis mainly through contaminated chicken eggs or egg products and has been a global public health threat. The spread and frequent outbreaks of this serotype through eggs correlate significantly with its exceptional survival in eggs, despite the antibacterial properties of egg white. Research on the survival mechanisms of S. Enteritidis in egg white will help develop effective strategies to control the contamination of eggs by this Salmonella serotype and help further elucidate the complex antibacterial mechanisms of egg white. This study revealed the importance of yoaE, a gene with unknown function, on the survival of S. Enteritidis in egg white, as well as its transcriptional regulation by CpxR. Our work provides the basis to reveal the mechanisms of survival of S. Enteritidis in egg white and the specific function of the yoaE gene.