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Nontyphoidal Salmonella is a bacterial and foodborne pathogen that poses a severe public health threat. However, the genetic diversity of different serogroups of nontyphoidal Salmonella in Guizhou is unknown. This study aimed to obtain the RNA secondary structure of the typical direct repeat sequences, the characteristics of clustered regularly interspaced short palindromic repeats (CRISPR) genotypes, and the genetic diversity of different serogroups of nontyphoidal Salmonella strains. The 342 nontyphoidal Salmonella strains were collected from nine cities (prefectures) of Guizhou province during 2013–2018, serotyped by slide agglutination, and examined the molecular genotypes by CRISPR method. The strains were divided into five serogroups. The dominant serogroup was group B (47.08%), followed by group D1 (36.55%). One hundred and thirty-five CRISPR genotypes were detected with 108 novel spacer sequences amongst 981 unique spacer sequences. The diversity of nontyphoidal Salmonella CRISPR loci was not only the deletion, duplication, or point mutation of spacer sequences but also the acquisition of new spacer sequences to form novel genotypes. The CRISPR genotyping was an effective typing method that could reveal the genetic diversity of different nontyphoidal Salmonella serotypes except for S. Enteritidis. [ABSTRACT FROM AUTHOR]

The genetic modification of cattle has many agricultural and biomedical applications. However, random integration often leads to the unstable or differentially expression of the exogenous genes, which limit the application and development of transgenic technologies. Finding a safe locus suitable for site-specific insertion and efficient expression of exogenous genes is a good way to overcome these hurdles. In this study, we efficiently integrated three targeted vector into the cattle Rosa26 (cRosa26) by CRISPR/Cas9 technology in which EGFP was driven by CAG, EF1a, PGK and cRosa26 endogenous promoter respectively. The CRISPR/Cas9 knock-in system allows highly efficient gene insertion of different expression units at the cRosa26 locus. We also find that in the four cell lines, EGFP was stable expressed at different times, and the CAG promoter has the highest activity to activate the expression of EGFP, when compared with the cRosa26, EF1a and PGK promoter. Our results proved that cRosa26 was a locus that could integrate different expression units efficiently, and supported the friendly expression of different expression units. Our findings described here will be useful for a variety of studies using cattle. [ABSTRACT FROM AUTHOR]