A reverse transcriptase-related protein mediates phage resistance and polymerizes untemplated DNA in vitro

Reverse transcriptases (RTs) are RNA-dependent DNA polymerases that usually function in the replication of selfish DNAs such as retrotransposons and retroviruses. Here, we have biochemically characterized a RT-related protein, AbiK, which is required for abortive phage infection in the Grampositive bacterium Lactococcus lactis. In vitro, AbiK does not exhibit the properties expected for an RT, but polymerizes long DNAs of ‘random’ sequence, analogous to a terminal transferase. Moreover, the polymerized DNAs appear to be covalently attached to the AbiK protein, presumably because an amino acid serves as a primer. Mutagenesis experiments indicate that the polymerase activity resides in the RT motifs and is essential for phage resistance in vivo. These results establish a novel biochemical property and a non-replicative biological role for a polymerase

Engineering the Campylobacter jejuni N-glycan to create an effective chicken vaccine

Campylobacter jejuni is a predominant cause of human gastroenteritis worldwide. Source-attribution studies indicate that chickens are the main reservoir for infection, thus elimination of C. jejuni from poultry would significantly reduce the burden of human disease. We constructed glycoconjugate vaccines combining the conserved C. jejuni N-glycan with a protein carrier, GlycoTag, or fused to the Escherichia coli lipopolysaccharide-core. Vaccination of chickens with the protein-based or E. colidisplayed glycoconjugate showed up to 10-log reduction in C. jejuni colonization and induced N-glycanspecific IgY responses. Moreover, the live E. coli vaccine was cleared prior to C. jejuni challenge and no selection for resistant campylobacter variants was observed. Analyses of the chicken gut communities revealed that the live vaccine did not alter the composition or complexity of the microbiome, thus representing an effective and low-cost strategy to reduce C. jejuni in chickens and its subsequent entry into the food chain.Peer reviewed: YesNRC publication: Ye

A large and diverse collection of bovine genome sequences from the Canadian Cattle Genome Project

Background: The Canadian Cattle Genome Project is a large-scale international project that aims to develop genomics-based tools to enhance the efficiency and sustainability of beef and dairy production. Obtaining DNA sequence information is an important part of achieving this goal as it facilitates efforts to associate specific DNA differences with phenotypic variation. These associations can be used to guide breeding decisions and provide valuable insight into the molecular basis of traits. Findings: We describe a dataset of 379 whole-genome sequences, taken primarily from key historic Bos taurus animals, along with the analyses that were performed to assess data quality. The sequenced animals represent ten populations relevant to beef or dairy production. Animal information (name, breed, population), sequence data metrics (mapping rate, depth, concordance), and sequence repository identifiers (NCBI BioProject and BioSample IDs) are provided to enable others to access and exploit this sequence information. Conclusions: The large number of whole-genome sequences generated as a result of this project will contribute to ongoing work aiming to catalogue the variation that exists in cattle as well as efforts to improve traits through genotype-guided selection. Studies of gene function, population structure, and sequence evolution are also likely to benefit from the availability of this resource