Project description:As vector-borne pathogens transit between the arthropod and vertebrate, adaptation is key for survival as each host varies and initiates unique defense mechanisms. An environmental signal that relapsing fever (RF) and Lyme causing spirochetes detect is the change of temperature between vector and mammal, yet incomplete genomes have hindered progress in understanding the genetic constituents expressed during tick colonization. We conducted a combined transcriptional and genomic sequence analysis to further assemble the ~150 kb linear plasmid (lp150) of Borrelia turicatae, a causative agent of RF borreliosis. Contiguous sequences (contigs), which were originally generated by Sanger sequencing, contained open reading frames (ORFs) identified to be up-regulated by the spirochetes when grown under tick-like conditions compared to the mammal. To aid in assembling the contigs, a PacBio RS I Single Molecule Real-Time DNA sequencing approach was used, given extended nucleotide reads over several thousand base pairs. A 36 kb locus was identified toward the 3‘ end of lp150, and expression of the ORFs was verified in the tick and mammal. We report the most complete version of lp150, and this study indicates that the plasmid likely facilitates vector colonization and establishing early mammalian infection
Project description:Anaplasma phagocytophilum infects a wide variety of host species and causes the diseases granulocytic anaplasmosis in humans, horses and dogs and tick-borne fever in ruminants. The objective of this research was to characterize differential gene expression in wild boar naturally infected with A. phagocytophilum by microarray hybridization using the GeneChip® Porcine Genome Array
Project description:Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus that causes severe clinical symptoms and mortality in humans. Haemaphysalis longicornis tick has been identified as the competent vector for SFTSV transmission. Although antiviral RNA interference (RNAi) in insects has been well documented, the degree to which RNAi contributes to antiviral defense in ticks is still largely elusive. In this study, utilizing arthropod-borne RNA viruses, including SFTSV, we find abundant virus-derived small interfering RNAs (vsiRNAs) are induced in H. longicornis after infection through either microinjection or natural blood-feeding. Furthermore, we identify a Dicer2-like homolog, the core protein of antiviral RNAi pathway, in H. longicornis and knocking down this gene exacerbated virus amplification. To counteract this antiviral RNAi of ticks, viruses have evolved suppressors of RNAi (VSRs). Here, we show that reduced viral replication inversely correlated with the accumulation of vsiRNAs in ticks after infection with recombinant sindbis virus (SINV) expressing heterologous VSR proteins. Elucidating the antiviral RNAi pathway of ticks by model arthropod-borne RNA viruses in vivo is critical to understanding the virus-host interaction, providing a feasible intervention strategy to control tick-borne arbovirus transmission.
