Role of plasmid- and chromosomally encoded Hha proteins in modulation of gene expression in E. coli O157:H7.

H-NS and Hha belong to the nucleoid-associated family of proteins and modulate gene expression in response to environmental stimuli. Genes coding for these proteins can be either chromosomally or plasmid-encoded. In this work, we analyse the regulatory role of the Hha protein encoded in the virulence plasmid of the enterohemorrhagic Escherichia coli O157:H7 (Hha(pO157)).

Integration host factor alleviates H-NS silencing of the Salmonella enterica serovar Typhimurium master regulator of SPI1, hilA.

Coordination of the expression of Salmonella enterica invasion genes on Salmonella pathogenicity island 1 (SPI1) depends on a complex circuit involving several regulators that converge on expression of the hilA gene, which encodes a transcriptional activator (HilA) that modulates expression of the SPI1 virulence genes. Two of the global regulators that influence hilA expression are the nucleoid-associated proteins Hha and H-NS. They interact and form a complex that modulates gene expression.

Dengue virus infections: comparison of methods for diagnosing the acute disease.

Background: The control of dengue depends solely on the control of the insect vector and efficient diagnosis of human cases as no vaccines or specific treatments are currently available. Existing diagnostic methods for suspected clinical cases are complicated by the short duration of viraemia and by serological cross-reactivity with epitopes from other flaviviruses.

Objectives: To evaluate PCR-based tests (nested reverse transcription (RT)-PCR and real-time RT-PCR) for the detection and serotyping of dengue virus and compare the results with those obtained with a widely used immunological test (IgM antibody capture ELISA-MAC-ELISA).