Project description:Investigation of whole genome gene expression level changes in a B. suis 1330 regA mutant, compared to the wild-type strain. The two-component system RegBA of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency. The mutant strain is affected in long-term persistence in vitro (this study) and in chronic infection in vivo (Abdou, E et al. 2013, Infect.Immun. 81: 2053-61). Using an original “in vitro model of persistence”, we compare large-scale transcriptome of the wild-type and ∆regA strains to identify the RegA-regulon potentially involved in the set-up of the persistence state.
Project description:The macrophage-Brucella interaction is critical for the establishment of a chronic Brucella infection. Smooth virulent B. suis strain 1330 (S1330) prevents macrophage cell death. However, rough attenuated B. suis strain VTRS1 induces strong macrophage cell death. To further investigate the mechanism of VTRS1-induced macrophage cell death, microarrays were used to analyze temporal transcriptional responses of murine macrophage-like J774. A1 cells infected with S1330 or VTRS1.
Project description:We report the identification of new noncoding RNAs in Brucella suis 1330 and that are associated to the chaperone protein Hfq Coimmunoprecipitation using Flag-tagged Hfq as bait
Project description:Brucellosis is one of the most common zoonotic epidemics worldwide. Vaccination against Brucellosis is an important control strategy to prevent the disease in many high-prevalence regions. At present, Brucella vaccine strain S2 is the most widely used vaccine in China. In this study, to uncover the related mechanisms underlie virulence attenuation of S2, we characterized the transcriptional profile of S2 and 1330 infected macrophages by transcriptome analysis. The results revealed that expressions of 440 genes were significantly different between macrophages infected by 1330 and S2. Data analysis showed that in the gene ontology term, the different expressed genes involved in innate immune response, phagoctyosis, recognition, and inflammatory response were significantly enriched. Pathway enrichment analysis indicated that the genes involved in transcriptional misregulation in cancer, staphylococcus aureus infection pathways and NF-kappa B signaling pathway were significantly affected. To reveal the molecular mechanisms related to different expression profiles of infected macrophages, the transcription levels of the different genes between the two bacterial genomes were also detected. In total, the transcription of 29 different genes was significantly changed in either culture medium or infected microphages. The results of current study can be conducive to the promotion of better understanding of the related mechanisms underlie virulence attenuation of S2 and interactions between host cells and brucella strains.
Project description:To explore the role of Brucella BI-1 in Brucella suis S2, we constructed the Brucella BI-1 deletion mutant strain and its complementary strain. We then determined the effect of Brucella BI-1 deletion on the physiological characteristics of Brucella suis S2 and revealed them via integrated transcriptomic and proteomic analyses. Brucella BI-1 deletion altered the membrane properties of Brucella suis S2 and decreased its resistance to acidic pH, H2O2, polymyxin B, and lincomycin. Additionally, deleting Brucella BI-1 led to defective growth, cell division, and viability in Brucella suis S2. In conclusion, our results revealed that Brucella BI-1 is a bacterial cytoprotective protein involved in membrane homeostasis, cell division, and stress resistance in Brucella suis S2.
Project description:The macrophage-Brucella interaction is critical for the establishment of a chronic Brucella infection. Smooth virulent B. suis strain 1330 (S1330) prevents macrophage cell death. However, rough attenuated B. suis strain VTRS1 induces strong macrophage cell death. To further investigate the mechanism of VTRS1-induced macrophage cell death, microarrays were used to analyze temporal transcriptional responses of murine macrophage-like J774. A1 cells infected with S1330 or VTRS1. Murine J774.A1 macrophages were plated in T75 at 8 x 10^6 cells per flask one day prior to infection, and then infected with B. suis S1330 or VTRS1 at a MOI of 200:1. Total RNAs were isolated by TRIzol and further purified using Qiagen RNeasy Mini Kit (Qiagen, Valencia, CA) at 0, 1, 2, 4, 8, 24, and 48 h post infection. The RNA samples were stored at -80 ºC until an Agilent 2100 BioAnalyzer (Agilent Technologies, Palo Alto, CA) was used to assess the concentrations and quality of RNA samples. Total RNA (20 µg) per sample was used for hybridization with Affymetrix mouse GeneChip 430 2.0 array. Preparation of cDNA, hybridization, quality controls and scanning of the GeneChip 430 2.0 arrays were performed according to the manufacturer's protocol (Affymetrix, Santa Clara, CA) .
