The cellular fatty acid composition of Brucella ovis and Brucella abortus strains was determined by gas-liquid chromatography. Both species were characterized by the presence of fatty acids 16:0, 17:0, 17:0 cyclopropane, 18:0, 18:1, and 19:0 cyclopropane; B. ovis also contained some 15:0. There were differences in the relative proportions of the fatty acids present, and it was possible to diffe...

Brucella abortus, the causative agent of bovine brucellosis, invades and replicates within cells inside a membrane-bound compartment known as the Brucella containing vacuole (BCV). After trafficking along the endocytic and secretory pathways, BCVs mature into endoplasmic reticulum-derived compartments permissive for bacterial replication. Brucella Type IV Secretion System (VirB) is a major viru...

The strategies that allow Brucella abortus to survive inside macrophages for prolonged periods and to avoid the immunological surveillance of major histocompatibility complex class II (MHC-II)-restricted gamma interferon (IFN-gamma)-producing CD4+ T lymphocytes are poorly understood. We report here that infection of THP-1 cells with B. abortus inhibited expression of MHC-II molecules and antige...

The identification of Brucella can be a time-consuming and labor-intensive process that places personnel at risk for laboratory-acquired infection. Here, we describe a real-time PCR assay for confirmation of presumptive Brucella isolates. The assay was designed in a multiplex format that will allow the rapid identification of Brucella spp., B. abortus, and B. melitensis in a single test.

In Brucella abortus, two small RNAs (sRNAs), AbcR1 and AbcR2, are responsible for regulating transcripts encoding ABC-type transport systems. AbcR1 and AbcR2 are required for Brucella virulence, as a double chromosomal deletion of both sRNAs results in attenuation in mice. Although these sRNAs are responsible for targeting transcripts for degradation, the mechanism utilized by the AbcR sRNAs to...

The intracellular pathogen Brucella abortus survives and replicates inside host cells within an endoplasmic reticulum (ER)-derived replicative organelle named the "Brucella-containing vacuole" (BCV). Here, we developed a subcellular fractionation method to isolate BCVs and characterize for the first time the protein composition of its replicative niche. After identification of BCV membrane prot...

In an enzyme-linked immunosorbent assay (ELISA), purified Brucella abortus and Escherichia coli peptidoglycan-linked lipoproteins gave a strong cross-reaction with sera from rabbits hyperimmunized with the heterologous lipoprotein. When smooth E. coli cells were used as ELISA antigens, the immunological cross-reaction was not observed unless the cells were treated to remove lipopolysaccharide a...

The outer membrane (OM) of the intracellular parasite Brucella abortus is permeable to hydrophobic probes and resistant to destabilization by polycationic peptides and EDTA. The significance of these unusual properties was investigated in a comparative study with the opportunistic pathogens of the genus Ochrobactrum, the closest known Brucella relative. Ochrobactrum spp. OMs were impermeable to...

Brucellosis is a costly contagious disease of human, domestic and wild animals. It is a serious health problem in Iran causing significant economic losses therefore, control approaches to prevent its spread are of great importance. In Iran, the species and biovars of virulent Brucella species are still under-reported due to the inadequate diagnostic protocols and insufficient laborator...

Identification of host responses at the gene transcription level provides a molecular profile of the events that occur following infection. Brucella abortus is a facultative intracellular pathogen of macrophages that induces chronic infection in humans and domestic animals. Using microarray technology, the response of macrophages 4 h following B. abortus infection was analyzed to identify early...