Advance and application of CRISPR/ Cas9 mediated genome editing technique on pathogenic microorganism / 中国人兽共患病学报

Clustered regularly interspaced short palindromic repeats (CRISPR) is an acquired immune system existing in archaea and bacteria with the long-term process of evolutionary.CRISPR/Cas9 gene editing system is a new type of gene editing technology developed based on the system.CRISPR/Cas9 is a more efficient method for gene targeting than the previous methods.It has been successfully applied for gene-modified of eukaryotes since 2012,but the reports about pathogenic microorgaisms are rarely.Here,the research progress in the structure,mechanism of CRISPR/Cas9 system and its applications on pathogenic microorgaisms is reviewed.

Mycobacterium vaccae induces a strong Th1 response that subsequently declines in C57BL/6 mice

Mycobacterium (M.) vaccae is a fast-growing species of saprophytic bacteria that is widely distributed. To understand the host immune responses induced by M. vaccae isolated from bovine submaxillary lymph nodes, C57BL/6 mice were infected with reference strain M. vaccae Bacillus Calmette-Guérin (BCG) and isolated M. vaccae using intraperitoneal injections. Comparison of the bacterial replication and organ pathology between M. vaccae and M. vaccae BCG revealed that M. vaccae was more malignant than M. vaccae in mice. We also demonstrated that serum from the M. vaccae-infected mice contained a higher expression level of gamma-interferon (IFN-γ), tumor necrosis factor alpha, monocyte chemoattractant protein-1, interleukin (IL)-4, IL-12, IL-10 and transforming growth factor beta than did the other groups, especially after week 4. Furthermore, when the numbers of CD3⁺CD4⁺IFN-γ⁺ and CD3⁺CD4⁺IL4⁺ cells in the infected mice were observed by flow cytometry, we found that a powerful T helper 1 (Th1) response was induced by M. vaccae infection, which was associated with the emergence of CD3⁺CD4⁺IFN-γ⁺ cells. However, the Th1 response declined over time, which was associated with appearance of the CD4⁺CD25⁺FoxP3⁺ and CD4⁺CD25⁺CD152⁺Treg cell reaction. In addition, a strong Th2 response was found. Finally, we found that M. vaccae infection increased the production of type I IFNs, which was associated with a reduced Th1 response.

Assembly and components of the type III secretion system of Salmonel l a / 中国人兽共患病学报

Salmonella is the main food-borne pathogen that causes food poisoning and gastroenteritis in human and ani-mals .The type III secretion system in Salmonella has played an important role in the invasion of host cell .In recent years ,the research of the composition ,assembly and related pathogenesis of Salmonella T3SS have made some progress .This article re-views the composition and assembly of Salmonella type III secretion system ,which could provide further study the pathogene-sis of Salmonella and also the new strategies and methods toward the treatment and prevention of Salmonella infections .