Investigation of the roles of AgrA and σB regulators in Listeria monocytogenes adaptation to roots and soil.

Little is known about the regulatory mechanisms that ensure the survival of the food-borne bacterial pathogen Listeria monocytogenes in the telluric environment and on roots. Earlier studies have suggested a regulatory overlap between the Agr cell-cell communication system and the general stress response regulator σB. Here, we investigated the contribution of these two systems to root colonisation and survival in sterilised and biotic soil.

Mild Stress Conditions during Laboratory Culture Promote the Proliferation of Mutations That Negatively Affect Sigma B Activity in Listeria monocytogenes.

In , the full details of how stress signals are integrated into the σ regulatory pathway are not yet available. To help shed light on this question, we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (σ). These mutants were tested for acid tolerance, a trait that is known to be under σ regulation, and they were found to display increased acid sensitivity, similar to a mutant lacking σ (Δ).

The σ-dependent regulatory sRNA Rli47 represses isoleucine biosynthesis in through a direct interaction with the transcript.

The facultative intracellular pathogen can persist and grow in a diverse range of environmental conditions, both outside and within its mammalian host. The alternative sigma factor Sigma B (σ) plays an important role in this adaptability and is critical for the transition into the host. While some of the functions of the σ regulon in facilitating this transition are understood the role of σ-dependent small regulatory RNAs (sRNAs) remain poorly characterized.

A Decade-Long Commitment to Antimicrobial Resistance Surveillance in Portugal.

Antimicrobial resistance (AMR) is a worldwide problem with serious health and economic repercussions. Since the 1940s, underuse, overuse, and misuse of antibiotics have had a significant environmental downside. Large amounts of antibiotics not fully metabolized after use in human and veterinary medicine, and other applications, are annually released into the environment.