Rickettsia is an important pathogenic entity among tick-borne diseases (TBD), which are considered serious emerging public health problems globally. In India, though the widespread distribution of ticks and TBD has been documented, its real burden remains underreported. a preliminary attempt, rickettsial surveillance was carried out in collected from Sirumalai, Eastern Ghats Tamil Nadu, India b...

The avian and human pathogen Chlamydophila (C.) psittaci represents a genetically heterogeneous species. To facilitate epidemiological surveys, more rapid yet highly specific molecular tests are needed. Currently used typing methods, i.e. serotyping and PCR-RFLP, have only limited sensitivity and are incapable of covering the wide spectrum of naturally occurring types of C. psittaci strains. In...

In previous investigations, we have examined the effect of OmpA signal peptide mutations on the secretion of the two heterologous proteins TEM beta-lactamase and nuclease A. During these studies, we observed that a given signal peptide mutation could affect differentially the processing of precursor OmpA-nuclease or precursor OmpA-lactamase. This observation led us to further investigate the in...

Chlamydia trachomatis is the leading cause of bacterial sexually transmitted diseases worldwide. Urogenital strains are classified into serotypes and genotypes based on the major outer membrane protein and its gene, ompA, respectively. Studies of the association of serotypes with clinical signs and symptoms have produced conflicting results while no studies have evaluated associations with ompA...

Our previous work established that DNA is naturally transferable on agar plates through a new transformation system which is regulated by the stationary phase master regulator RpoS in Escherichia coli. In this transformation system, neither additional Ca(2+) nor heat shock is required. Instead, transformation is stimulated by agar. The membrane protein OmpA, a gated pore permeable to ions and l...

Anaplasma phagocytophilum is the tick-transmitted obligate intracellular bacterium that causes human granulocytic anaplasmosis (HGA). A. phagocytophilum binding to sialyl Lewis x (sLe(x)) and other sialylated glycans that decorate P selectin glycoprotein 1 (PSGL-1) and other glycoproteins is critical for infection of mammalian host cells. Here, we demonstrate the importance of A. phagocytophilu...

To the Editor: In response to a recent report that suggested human infection with Rickettsia japonica in northeastern Thailand (1), we phylogenetically reexamined spotted fever group rickettsiae (SFGR) from Thailand. The organism had been isolated from a male Haemaphysalis hystricis tick found on Mt. Doi Suthep, Chiang Mai, northern Thailand, in December 2001. The strain was designated TCM1 and...

Pro-OmpA that is synthesized in vitro can assemble into bacterial inner membrane vesicles in the presence of ATP and NADH. We have purified pro-OmpA to determine which additional soluble proteins are necessary for its membrane assembly. [35S]Pro-OmpA was bound to Sepharose-linked antibody to OmpA, then eluted with 8 M urea and chromatographed on an anion-exchange resin in 8 M urea. This pro-Omp...

The basic biochemical and biophysical principles by which chaperone-bound membrane proteins are targeted to the outer membrane of Gram-negative bacteria for insertion and folding are unknown. Here we compare spontaneous folding of outer membrane protein A (OmpA) of Escherichia coli from its urea-unfolded form and from the complex with its periplasmic chaperone Skp into lipid bilayers. Skp facil...