Prevalence and phylogenetic characterization of canine coronavirus from diseased pet dogs in Beijing,China

Dear Editor,Canine coronavirus including canine coronavirus(CCoV)and canine respiratory coronavirus(CRCoV)have been recognized as pathogenic viruses to dogs worldwide,causing enteric and respiratory issues(Buonavoglia et al.,2006).Zoonotic transfer of the viruses from the animal kingdom to humans has been repeatedly observed over the past decade,

Strain heterogeneity,cooccurrence network,taxonomic composition and functional profile of the healthy ocular surface microbiome

Background:There is growing evidence indicating that the microbial communities that dwell on the human ocular surface are crucially important for ocular surface health and disease.Little is known about interspecies interactions,functional profiles,and strain heterogeneity across individuals in healthy ocular surface microbiomes.Methods:To comprehensively characterize the strain heterogeneity,cooccurrence network,taxonomic composition and functional profile of the healthy ocular surface microbiome,we performed shotgun metagenomics sequencing on ocular surface mucosal membrane swabs of 17 healthy volunteers.Results:The healthy ocular surface microbiome was classified into 12 phyla,70 genera,and 140 species.The number of species in each healthy ocular surface microbiome ranged from 6 to 47,indicating differences in microbial diversity among individuals.The species with high relative abundances and high positivity rates were Streptococcus pyogenes,Staphylococcus epidermidis,Propionibacterium acnes,Corynebacterium accolens,and Enhydrobacter aerosaccus.A correlation network analysis revealed a competitive interaction of Staphylococcus epidermidis with Streptococcus pyogenes in ocular surface microbial ecosystems.Staphylococcus epidermidis and Streptococcus pyogenes revealed phylogenetic diversity among different individuals.At the functional level,the pathways related to transcription were the most abundant.We also found that there were abundant lipid and amino acid metabolism pathways in the healthy ocular surface microbiome.Conclusion:This study explored the strain heterogeneity,cooccurrence network,taxonomic composition,and functional profile of the healthy ocular surface microbiome.These findings have important significance for the future development of probiotic-based eye therapeutic drugs.

Genetic and antigenic characterization of recombinant nucleocapsid proteins derived from canine coronavirus and canine respiratory coronavirus in China

To characterize the antigenicity of nucleocapsid proteins(NP) derived from canine coronavirus(CCo V) and canine respiratory coronavirus(CRCo V) in China, the N genes of CCo V(CCo V-BJ70) and CRCo V(CRCo V-BJ202) were cloned from swabs obtained from diseased pet dogs in Beijing and then sequenced. The recombinant NPs(r NPs) were expressed in Escherichia coli and purified by nickel-affinity column and size exclusion chromatography. Sequencing data indicated that the N genes of CCo V-BJ70 and CRCo V-BJ202 belonging to two distinctly different groups were relatively conserved within each subgroup. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) results showed that r NPs of CCo V and CRCo V were expressed efficiently and isolated with a final purity of over 95%. Western blot analysis revealed the r NP from CRCo V could cross-react with mice antisera against human coronavirus(HCo V-229 E, NL63, OC43, HKU1), while r NP of CCo V had cross-reactivity with only anti-sera against viruses belonging to the same group(HCo V-229 E and NL63). In summary, CCo V and CRCo V r NPs were successfully expressed in E. coli and showed antigenic cross-reactivity with antisera raised against human coronaviruses. These findings indicate that further serologic studies on coronavirus infections at the animal-human interface are needed.

Genome reduction of Borrelia burgdorferi:two TCS signaling pathways for two distinct host habitats

Lyme disease is an emerging tick-borne disease in the U.S., Europe, and Asia including China, and has become the most common vector-borne disease in both Europe and North America. Infection is caused by the spirochetal pathogen Borrelia burgdorferi sensu lato, transmitted via tick bites. The clinical manifestations of Lyme disease range from fever and skin lesions （erythema migrans） to multisystem disorders such as arthritis, carditis, and neuroborreliosis （Steere et al., 2004）. Although treatable with antibiotics, the infection is underdiagnosed, and the late stages of Lyme disease are difficult to treat. No commercial vaccine is available. An alternative strategy is to block the transmis- sion of B. burgdorferi. Understanding how B. burgdorferi is maintained in the enzootic cycle is the key for such strategy. B. burgdorferi is maintained in an enzootic cycle con- taining two markedly different hosts, an arthropod vector and a mammalian host （Radolf et al., 2012; Samuels, 2011）. B. burgdorferi must be able to adapt to both distinct host environments. On the other hand, as a non-free living path- ogen, B. burgdorferi has a dramatically reduced genome. Remarkably, B. burgdorferi has evolved in utilizing its limited genomic capabilities to adapt to and survive in these two host environments.