Borrelia burgdorferi Requires the Alternative Sigma Factor RpoS for Dissemination within the Vector during Tick-to-Mammal Transmission

PLoS Pathogens

Christian H. Eggers¹  Star M. Dunham-Ems²  Melissa J. Caimano²  Justin D. Radolf² 

[1] Department of Biomedical Sciences, Quinnipiac University, Hamden, Connecticut, United States of America;Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, United States of America

关键词: Nymphs;    Spirochetes;    Blood;    Larvae;    Basement membrane;    Borrelia burgdorferi;    Mammals;    Regulons;   

DOI  :  10.1371/journal.ppat.1002532

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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 disulfide reductase, which among other functions, provides NAD+ for glycolysis. Our data suggest that spirochetes default to an RpoS-independent program for round body formation upon sensing that the energetics for transmission are unfavorable.

【 授权许可】

CC BY