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...

Background: The intrinsic heterogeneity determination in Brucella Lipopolysaccharide (LPS) is important for explaining its chemicalnature and biological behavior. This is significant for practical purposes, since LPS is the most relevant antigen during infectionand vaccination.Objectives: The purpose of the present study was to compare biochemical and immunological differences of LPS and lipid ...

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...

A vector for the expression of foreign antigens in the vaccine strain Brucella abortus S19 was developed by using a DNA fragment containing the regulatory sequences and the signal peptide of the Brucella bcsp31 gene. This fragment was cloned in broad-host-range plasmid pBBR4MCS, resulting in plasmid pBEV. As a reporter protein, a repetitive antigen of Trypanosoma cruzi was used. The recombinant...

1. Comparison of the infections of chick embryos by the chorio-allantoic route indicates that Bacterium tularense and Brucella suis, abortus, and melitensis exhibit varying degrees of facultative intracellular parasitism. Pasteurella pestis is adapted to rapid proliferation and spread in the intercellular fluids. 2. In the early stages of infection Bacterium tularense has a marked affinity for ...

A colony blot enzyme-linked immunosorbent assay was developed for the rapid identification of smooth Brucella species, i.e., Brucella abortus, B. melitensis, and B. suis. Bacterial colonies from plates were blotted onto nitrocellulose disks, lysed by immersion in chloroform, and reacted with BRU 38, a rat monoclonal antibody with specificity for the O side chain of B. abortus. Reaction with ant...