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Many gram-negative bacterial pathogens employ type III secretion systems for infectious processes. Chlamydiae are obligate intracellular bacteria that encode a conserved type III secretion system that is likely requisite for growth. Typically, genes encoding type III secretion systems are located in a single locus; however, for chlamydiae these genes are(More)
Borrelia burgdorferi spirochetes can circumvent the vertebrate host's immune system for long periods of time. B. burgdorferi sensu stricto and B. afzelii, but not B. garinii, bind the complement inhibitor factor H to protect themselves against complement-mediated opsonophagocytosis and killing. We found that factor H binding and complement resistance are(More)
Lyme disease is a tick-borne infection that can lead to chronic, debilitating problems if not recognized or treated appropriately. Borrelia burgdorferi, the causative agent of Lyme disease, is maintained in nature by a complex enzootic cycle involving Ixodes ticks and mammalian hosts. Many previous studies support the notion that B. burgdorferi(More)
Chlamydia spp. are obligate intracellular bacterial pathogens that alternate between two metabolically and morphologically distinct developmental forms, and differentiation depends on transcriptional regulation. Genome sequencing of Chlamydia trachomatis revealed an ORF, CT630 (chxR), whose amino acid sequence contains a winged helix-turn-helix motif(More)
Chlamydia trachomatis is maintained through a complex bi-phasic developmental cycle that incorporates numerous processes that are poorly understood. This is reflective of the previous paucity of genetic tools available. The recent advent of a method for transforming Chlamydia has enabled the development of essential molecular tools to better study these(More)
Chlamydia are obligate intracellular bacterial pathogens that cause a variety of diseases. Like many Gram-negative bacteria, they employ type III secretion systems (T3SS) for invasion, establishing and maintaining their unique intracellular niche, and possibly cellular exit. Computational structure prediction indicated that ORF CT584 is homologous to other(More)
In previous studies we have characterized the cp32/18 loci in Borrelia burgdorferi 297 which encode OspE and OspF orthologs and a third group of lipoproteins which possess OspE/F-like leader peptides (Elps). To further these studies, we have comprehensively analyzed their patterns of expression throughout the borrelial enzootic cycle. Serial dilution(More)
Serum resistance, an important virulence determinant of Borrelia burgdorferi sensu lato strains belonging to the Borrelia afzelii and B. burgdorferi sensu stricto genotypes, is related to binding of the complement inhibitor factor H to the spirochete surface protein outer surface protein E (OspE) and its homologues. In this study, we show that the(More)
Borrelia burgdorferi differentially expresses many of the OspE/F/Elp paralogs during tick feeding. These findings, combined with the recent report that stable B. burgdorferi infection of mammals occurs only after 53 h of tick attachment, prompted us to further analyze the expression of the OspE/F/Elp paralogs during this critical period of transmission.(More)
Neonates face a high risk of infection because of the immaturity of their immune systems. Although the transplacental transfer of maternal antibodies to the fetus may convey improved postnatal immunity, this transfer occurs late in gestation and may fail to prevent in utero infection. Both fetal immunization and in utero exposure to antigen can result in a(More)