Gene expression analysis of Xenopsylla cheopis (Siphonaptera: Pulicidae) suggests a role for reactive oxygen species in response to Yersinia pestis infection.
Fleas are vectors for a number of pathogens including Yersinia pestis, yet factors that govern interactions between fleas and Y. pestis are not well understood. Examining gene expression changes in infected fleas could reveal pathways that affect Y. pestis survival in fleas and subsequent transmission. We used suppression subtractive hybridization to identify genes that are induced in Xenopsylla cheopis (Rothschild) (Siphonaptera: Pulicidae) in response to oral or hemocoel infection with Y. pestis. Overall, the transcriptional changes we detected were very limited. We identified several genes that are likely involved in the production or removal of reactive oxygen species (ROS). Midgut ROS levels were higher in infected fleas and antioxidant treatment before infection reduced ROS levels and resulted in higher bacterial loads. An ROS-sensitive mutant strain of Y. pestis lacking the OxyR transcriptional regulator showed reduced growth early after infection. Our results indicate that ROS may limit Y. pestis early colonization of fleas and that bacterial strategies to overcome ROS may enhance transmission.
Department of Microbiology and Molecular Biology, Brigham Young University, WIDB 893, Provo, UT 84602, USA.
SourceJournal of medical entomology 49:2 2012 Mar pg 364-70
Gene Expression Profiling
Reactive Oxygen Species
Real-Time Polymerase Chain Reaction
Sequence Analysis, DNA
Pub Type(s)Journal Article
Research Support, Non-U.S. Gov't