The mechanism of folding and membrane insertion of integral membrane proteins, including helix bundle and beta-barrel proteins is not well understood. A key question is whether folding and insertion are coupled or separable processes. We have used the beta-barrel outer membrane protein A (OmpA) of Escherichia coli as a model to study the kinetics of folding and insertion into dioleoylphosphatid...

Abstract Spotted fever group rickettsiae, mainly maintained and transmitted by ticks, are important etiological agents of (re)emerging zoonotic diseases worldwide. It is great significance to investigate spotted rickettsiae in ticks different areas for the prevention control rickettsioses. In this study, a total 305 were collected from wild domestic animals Chongqing, Guizhou, Yunnan, Guangxi p...

The cloning and sequencing of the Brucella abortus major 25-kDa outer membrane protein (OMP) is reported. The 25-kDa (group 3) OMP has been proposed, on the basis of amino acid composition, to be the counterpart of OmpA (D. R. Verstraete, M. T. Creasy, N. T. Caveney, C. L. Baldwin, M. W. Blab, and A. J. Winter, Infect. Immun. 35:979-989, 1982). However, the amino acid sequence predicted from th...

A Chlamydophila psittaci species-specific real-time PCR targeting the rDNA ribosomal spacer was developed as well as a genotype-specific real-time PCR targeting the Cp. psittaci outer membrane protein A (ompA) gene. The SYBR Green-based species-specific real-time PCR detected Cp. psittaci genotypes A to F, and the recently discovered E/B genotype. The genotype-specific real-time PCR could easil...

ompA, and htrA); 11 of these ticks were from the patient’s dogs. In all properties where ticks were collected, at least 1 was PCR positive. Thus, we detected R. parkeri in half (4/8) of investigated households. All the sequences generated for the ompA and htrA genes showed 100% identity to sequences from the Rickettsia parkeri strain Portsmouth (GenBank accession no. CP003341.1). We deposited i...

Bacterial overgrowth in the stomach may occur under conditions of diminished or absent acid secretion. Under these conditions, secretion of the hormone gastrin is elevated. Alternatively, bacterial factors may directly stimulate gastrin. Consistent with this hypothesis, we found that mice colonized for 2 months with a mixed bacterial culture of opportunistic pathogens showed an increase in seru...

We determined that the putative upstream promoter of the long transcript (P1) of ompA, the gene encoding the major outer membrane protein of Chlamydia trachomatis L2, is recognized in vitro by the major sigma factor of chlamydiae, sigma 66. We found no evidence that the putative downstream promoter of the short ompA transcript (P1) is functional in vitro. RNase protection of guanylyltransferase...

Introduction: Acinetobacter baumannii is associated with hospital-acquired infections. Outer membrane protein A of A.baumannii (AbOmpA) is a well-characterized virulence factor which has important roles in pathogenesis of this bacterium. Methods: Based on our PCR-sequencing of ompA gene in the clinical isolates, AbOmpA protein can be categorized into two types, named here type-1 and type-2. We ...

granulocytic ehrlichiosis in Europe: clinical and laboratory findings for four patients from Slovenia. Use of CRH/he Lyme disease mouse model for the recovery of a Spanish isolate of Borrelia garinii from erythema migrans lesions. To the Editor: Five species of tick-associated rickettsiae have been identified in China; of these, three are human pathogens and two are of unknown pathogenicity (1)...

BACKGROUND The small RNA (sRNA) MicA has been shown to post-transcriptionally regulate translation of the outer membrane protein A (OmpA) in Escherichia coli. It uses an antisense mechanism to down-regulate OmpA protein synthesis and induce mRNA degradation. MicA is genomically localized between the coding regions of the gshA and luxS genes and is divergently transcribed from its neighbours. Tr...