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Borrelia Burgdorferi Requires The Alternative Sigma Factor Rpos For Dissemination Within The Vector During Tick-To-Mammal Transmission, Star M. Dunham-Ems, Melissa J. Caimano, Justin D. Radolf

UCHC Articles - Research

While the roles of rpoSBb and RpoS-dependent genes have been studied extensively within the mammal, the contribution of the RpoS regulon to the tick-phase of the Borrelia burgdorferi enzootic cycle has not been examined. Herein, we demonstrate that RpoS-dependent gene expression is prerequisite for the transmission of spirochetes by feeding nymphs. RpoS-deficient organisms are confined to the midgut lumen where they transform into an unusual morphotype (round bodies) during the later stages of the blood meal. We show that round body formation is rapidly reversible, and in vitro appears to be attributable, in part, to reduced levels of Coenzyme A …