Project description:Identification of Genes and Genomic Islands Correlated with High Pathogenicity through Tilling Microarray-Based Comparative Genomics in S. suis. Streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. S. suis isolates have been categorized into groups of different levels of pathogenicity, with sequence type (ST) ST1 clonal complex strains having a higher degree of virulence than other STs. However, the genetic basis of the differences in pathogenicity is still poorly understood. In this study, a comprehensive genomic comparison of 31 S. suis strains from different clinical sources with the genome sequence of the high pathogenicity (HP) strain GZ1 was conducted using NimbleGen’s tilling microarray platform.
Project description:Transcriptional profiling of a S. suis 10flpS::spcR mutant strain in which the flpS gene has been disrupted by an insertion of a spectinomycin resistance cassette (spcR). We compared the expression profile of S. suis strain 10 with that of S. suis strain 10flpS::spcR during exponential and stationary growth of the bacterial cells.
Project description:Streptococcus suis is an important emerging worldwide pig pathogen and zoonotic agent with rapid evolution of virulence and drug resistance. Licochalcone A, used in traditional Chinese medicine, exhibits antimicrobial, antioxidant and anti-inflammatory activities. Herein, a whole-genome DNA microarray was used to investigate the global transcriptional regulation of Streptococcus suis 05ZYH33 treated by subinhibitory concentration of licochalcone A. 132 genes were differentially regulated upon liochalcone A treatment, including 78 genes up-regulated and 54 genes down-regulated which included many central biological functions such as metabolism, transcription and translation. We tried to investigate the antimicrobial mechanism of licochalcone A in the aspect of bacterial cell cycle control. Our analysis indicated that licochalcone A might inhibit the growth of S. suis by controlling the replication initiation and cell division through amino acid metabolism.
Project description:To investigate the effect of CodY mutation on the gene expression in Streptococcus suis serotype 2 SC19 strain, we have employed whole genome microarray expression profiling as a discovery platform to identify genes regulated by CodY mutation. DNA microarray analysis was performed using an Agilent custom-designed oligonucleotide microarray. Based upon the whole genome sequence of SC19 , specific 60-mer oligonucleotide probes were designed using eArray (https://earray.chem.agilent.com/earray/), to cover all annotated genes. Probes were printed seven times on microarray slides. Three biological replicates of total RNA from two wild type strains and from two codY mutant strains were amplified and labeled with Cy3-CTP using Low Input Quick Amp Labeling Kit, one-color(Agilent technologies, US), following the manufacturer’s instructions. Labeled cRNA was purified using the RNeasy mini kit (Qiagen). After fragmentation, microarray slides were hybridized with 600 ng Cy3-labeled cRNA. Hybridization was performed at 65 °C for 17 h with rotation at 10 rpm. Microarray slides were washed and scanned by an Agilent Microarray Scanner (G2565BA). Those genes with greater than two-fold change ratios were regarded as differentially expressed genes. codY mutation induced gene expression in Streptococcus suis serotype 2 SC19 was detected in two wild type and two codY mutated strain of Streptococcus suis serotype 2.
Project description:Streptococcus suis is a major swine pathogen that can be transmitted to humans causing severe symptoms. A large human outbreak was described in China, where approximately 25% out of 215 infected humans developed an unusual streptococcal toxic shock-like syndrome (STSLS). Albeit increased expression of inflammatory mediators following infection by the Chinese S. suis strain was suggested as responsible for STSLS case severity, the mechanisms involved are still poorly understood. In this study, we investigated the host innate immune response to infection by either one of 3 strains of S. suis: 89-1591 (Canadian, intermediate virulence), P1/7 (European, high virulence), and SC84 (Chinese, epidemic strain). Using Illumina microarray and validating those results with qPCR and Luminex assay, infected mice showed elevated expression of mainly pro-inflammatory chemokine and cytokine genes. Generally, pro-inflammatory genes were expressed at a higher level in mice infected with S. suis strain SC84 > P1/7 > 89-1591. Interestingly, IFNγ was expressed at much higher levels only in mice infected with the S. suis strain SC84, which could potentially explain some of the STSLS symptoms. IFNγ-KO mice infected with SC84 showed better survival than WT mice while no differences was seen in mice infected with highly virulent P1/7 strain. Overall, our results show an important role of IFNγ in S. suis infections and might explain in part the increased virulence of SC84 responsible for a recent outbreak in China.