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: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: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:Brucellosis, caused by Brucella spp, is an important zoonotic disease leading to enormous economic losses in livestock and posing great threat to public health worldwide. The live attenuated Brucella suis (B. suis) strain S2 is a safe and effective vaccine, and it is most widely used in animals in China. However, S2 vaccination in animals may raise debates and concerns in terms of safety to primates, particularly human. In this study, using cynomolgus monkey as an animal model, we evaluated the safety of the S2 vaccine strain on primate, in addition, we performed transcriptome analysis to determine gene expression profiling on cynomolgus monkeys immunized with the S2 vaccine. Our results suggested that the S2 vaccine was safe to cynomolgus monkeys. Transcriptome analysis identified 663 differentially expressed genes (DEGs), of which 348 were significantly up-regulated and 315 were remarkably down-regulated. Gene Ontology (GO) classification and KEGG pathway analysis indicated that these DEGs were involved in various biological processes, including chemokine signaling pathway, actin cytoskeleton regulation, defense response, immune system processing, and type I interferon signaling pathway. The molecular functions of the DEGs mainly comprised of 2'-5'-oligoadenylate synthetase activity, double-stranded RNA binding and actin binding. Moreover, the cellular components of these DEGs included integrin complex, myosin II complex and blood microparticle. Our findings alleviate the concerns in safety of the S2 vaccine on primates and provide genetic basis of mammalian host response and gene regulation after vaccination with the S2 vaccine.
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: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:Brucella suis infects macrophages and dendritic cells. Wild boars act as reservoirs and carriers of Brucella suis biovar 2, and there is evidence that wild boar can be the main source of infection for domestic pigs through the venereal route. Transmission through this route could be an important path for disesease dissemination. The result from this study will contribute to the overall understanding of the molecular pathogenic mechanisms involved during Brucella suis infection in European wild boar.