virulence determinants RARP2 and RapL mitigate IFN- signaling in primary human dermal microvascular endothelial cells.

We compared the growth characteristics of a virulent strain (Sheila Smith) to an attenuated stain (Iowa) and a non-pathogenic species () in primary human dermal microvascular endothelial cells (HDMEC). All replicated in Vero cells, however, only the Sheila Smith strain productively replicated in HDMECs. The Iowa strain showed minimal replication over a 24-h period, while lost viability and induced lysis of the HDMECs via a rapid programmed cell death response.

Completed genomes for isolated from ticks and quality controlled for motility phenotype.

Complete genomes of were sequenced with Illumina and PacBio technologies from low-passage isolates from ticks. These isolates were quality controlled for intact , a regulator of actin-based motility that is negatively selected for in culture. The Sheila Smith strain was re-sequenced using the same methodology.

Identification of an autotransporter peptidase of Rickettsia rickettsii responsible for maturation of surface exposed autotransporters.

Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant. Autotransporter translocation to the bacterial outer surface, also known as type V secretion, involves formation of a β-barrel autotransporter domain in the periplasm that inserts into the outer membrane to form a pore through which the N-terminal passenger domain is passed and exposed on the outer surface. Two major surface antigens of Rickettsia rickettsii, are known to be surface exposed and the passenger domain cleaved from the autotransporter domain.

Chlamydia trachomatis suppresses host cell store-operated Ca entry and inhibits NFAT/calcineurin signaling.

The obligate intracellular bacterium, Chlamydia trachomatis, replicates within a parasitophorous vacuole termed an inclusion. During development, host proteins critical for regulating intracellular calcium (Ca) homeostasis interact with the inclusion membrane. The inclusion membrane protein, MrcA, interacts with the inositol-trisphosphate receptor (IPR), an ER cationic channel that conducts Ca.