Role of Sca2 and RickA in the Dissemination of Rickettsia parkeri in Amblyomma maculatum.

摘要: ABSTRACT The Gram-negative obligate intracellular bacterium Rickettsia parkeri is an emerging tick-borne human pathogen. Recently, R. Sca2 and RickA have been implicated in adherence actin-based motility vertebrate host cell infection models; however, the rickettsia-derived factors essential to tick are unknown. Using mutants lacking functional or compare actin polymerization, replication, cell-to-cell spread vitro, similar phenotypes mammalian cells were observed. Specifically, polymerization cultured controlled by two separate proteins a time-dependent manner. To assess role of dissemination host, Rickettsia-free Amblyomma maculatum, natural vector parkeri, was exposed wild-type, rickA::tn, sca2::tn bacteria, individual tissues, including salivary glands, midguts, ovaries, hemolymph, analyzed at 12 h after continued bloodmeal acquisition for 3 7 days postexposure. Initially, ticks wild-type had highest rickettsial load across all organs; loads decreased rickettsiae cleared from ovaries In contrast, parkeririckA::tn parkerisca2::tn comparatively lower loads, but bacteria persisted organs days. These data suggest that while function cells, absence these did not change patterns within vector.