Iron-dependent reconfiguration of the proteome underlies the intracellular lifestyle of Brucella abortus.

Brucella ssp. is a facultative intracellular pathogen that causes brucellosis, a worldwide zoonosis that affects a wide range of mammals including humans. A critical step for the establishment of a successful Brucella infection is its ability to survive within macrophages. To further understand the mechanisms that Brucella utilizes to adapt to an intracellular lifestyle, a differential proteomic study was performed for the identification of intracellular modulated proteins. Our results demonstrated that at 48 hours post-infection Brucella adjusts its metabolism in order to survive intracellularly by modulating central carbon metabolism. Remarkably, low iron concentration is likely the dominant trigger for reprogramming the protein expression profile. Up-regulation of proteins dedicated to reduce the concentration of reactive oxygen species, protein chaperones that prevent misfolding of proteins, and proteases that degrade toxic protein aggregates, suggest that Brucella protects itself from damage likely due to oxidative burst. This proteomic analysis of B. abortus provides novel insights into the mechanisms utilized by Brucella to establish an intracellular persistent infection and will aid in the development of new control strategies and novel targets for antimicrobial therapy.

Detection of duck enteritis virus by polymerase chain reaction.

Duck enteritis virus (DEV), a herpesvirus, is the causative agent of duck viral enteritis in free-flying, feral, and domesticated members of the Anatidae family. HindIII-digested DEV DNA was cloned into the plasmid pBluescript, and a 1.95-kb fragment was sequenced. This fragment codes for the 3' region of the DEV homologues of varicella-zoster virus (VZV) open reading frame (ORF) UL6 and the 5' region of VZV UL7. Alignment of the putative peptide fragments for DEV UL6 and UL7 showed a 64% and 37% identity with VZV UL6 and UL7, respectively. Primers located in the highly conserved domain of the UL6 gene were used for a polymerase chain reaction (PCR) assay, which was able to amplify DEV DNA. The PCR assay also amplified DEV DNA from the original outbreak samples and/or after passage in Muscovy duck embryos.