RNA helicase DExD/H-box 5 modulates intestinal microbiota in mice.

The RNA helicase DExD/H-box (DDX) family of proteins plays a central role in host cellular RNA metabolism, including mRNA regulation, microRNA biogenesis, and ribosomal processing. DDX5, also known as p68, promotes viral replication and tumorigenesis. However, there have been no studies on the regulation of the intestinal microbiota by DDX family proteins. We constructed DDX5 knockout mice (Ddx5+/-) using CRISPR/CAS9 technology. Subsequently, DDX5 knockout mice were analyzed for PCR products, mRNA levels, protein expression, immunohistochemistry, and histopathological lesions. Fecal (n = 12) and ileum (n = 12) samples were collected from the Ddx5+/- and wild-type (Ddx5+/+) mice. The diversity, richness, and structural separation of the intestinal microbiota of the Ddx5+/- and Ddx5+/+ mice were determined by 16S rRNA sequencing and analysis. Ddx5+/- mice were successfully established, and the ileum had normal morphology, a clear layer of tissue structures, and neatly arranged cupped cells. DDX5 knockout mice did not exhibit adverse effects on the ileal tissue. Microbial diversity and abundance were not significantly different, but the microbial structure of the intestinal microbiota was clustered separately between Ddx5+/+ and Ddx5+/- mice. Furthermore, we found that the relative abundance of Akkermansia and Clostridium_sensu_stricto_1 in the Ddx5+/- mice was significantly lower than in the Ddx5+/+ mice. These analyses indicated specific interactions between the intestinal microbiota and DDX5 protein. Our results indicate that DDX5 has a significant effect on the composition of the intestinal microbiota in mice, suggesting its potential as a promising novel target for the treatment of inflammation and tumorigenesis in the intestine.

Genome sequence of Mycoplasma capricolum subsp. capripneumoniae strain M1601.

Mycoplasma capricolum subsp. capripneumoniae is the causative agent of contagious caprine pleuropneumonia, a devastating disease of goats listed by the World Organization for Animal Health. Here we report the first complete genome sequence of this organism (strain M1601, a clinically isolated strain from China).

Genotyping of Haemophilus parasuis isolated from northwest China using PCR-RFLP based on the ompA gene.

Outer membrane proteins (OMPs) are the major virulent factors of Haemophilus parasuis. PCR-RFLP targeting the ompA gene was conducted to investigate the possibility of genotyping H. parasuis in this study. Fifteen reference strains and 49 isolates from pig farms in northwest China were genotyped by PCR-RFLP with a pair of specific primers. The results indicated that both the 15 reference strains and 49 isolates could be classified into 8 different genotypes by PCR-RFLP, respectively. Seven genotypes including AA, BB, BA, CA, BC, BD and CD existed simultaneously in the reference strains and isolates, but genotype CB only existed in the isolated strains. Interestingly, genotypes BA, CD and CA were only found in diseased pigs and accounted for 38.8%, 22.4% and 18.4% of the isolates, respectively. On the other hand, strains isolated from apparently healthy pigs were classified into genotypes AA, BB, BC and CB. However, the virulent reference serovar 1 strain has an AA genotype, and the fact that nearly all strains from the healthy pigs belonged to serovars classed as virulent suggests that these genotypes might also include virulent strains; therefore, further validation with more field strains is needed. The capability of the RFLP-PCR method based on the ompA gene for genotyping H. parasuis isolates indicates that this method may be a useful tool for epidemiological study.