Bacterial TonB-dependent transducers interact with the anti-σ factor in absence of the inducing signal protecting it from proteolysis.

Competitive bacteria like the human pathogen Pseudomonas aeruginosa can acquire iron from different iron carriers, which are usually internalized via outer membrane TonB-dependent receptors (TBDRs). Production of TBDRs is promoted by the presence of the substrate. This regulation often entails a signal transfer pathway known as cell-surface signaling (CSS) that involves the TBDR itself that also functions as transducer (and is thus referred to as TBDT), a cytoplasmic membrane-bound anti-σ factor, and an extracytoplasmic function σ (σECF) factor.

The Prc and CtpA proteases modulate cell-surface signaling activity and virulence in .

Cell-surface signaling (CSS) is a signal transfer system of Gram-negative bacteria that produces the activation of an extracytoplasmic function σ factor (σ) in the cytosol in response to an extracellular signal. Activation requires the regulated and sequential proteolysis of the σ-associated anti-σ factor, and the function of the Prc and RseP proteases. In this work, we have identified another protease that modulates CSS activity, namely the periplasmic carboxyl-terminal processing protease CtpA.

Clover Root Exudates Favor sp. HR1a Establishment in the Rhizosphere and Promote Phenanthrene Rhizoremediation.

Rhizoremediation is based on the ability of microorganisms to metabolize nutrients from plant root exudates and, thereby, to cometabolize or even mineralize toxic environmental contaminants. sp. HR1a is a bacterial strain able to degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs).

Degradation of phenanthrene by Novosphingobium sp. HS2a improved plant growth in PAHs-contaminated environments.

At the same time that the European Union (EU) policy recommend to direct efforts towards reductions of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and mining residues, there is the need to increase the cultivable areas within Europe to cope with the increasing demands for food and energy crops. Bioremediation is a good technique for the restoration of contaminated soils; however, it has not been used extensively because of the variability of the outcome. This variability is frequently due to a bad establishment of foreign degrading populations in soil.

The pGRT1 plasmid of Pseudomonas putida DOT-T1E encodes functions relevant for survival under harsh conditions in the environment.

Pseudomonas putida DOT-T1E has the capacity to grow in the presence of high concentrations of toluene. This ability is mainly conferred by an efflux pump encoded in a self-transmissible 133 kb plasmid named pGRT1. Sequence analysis of the pGRT1 plasmid revealed several key features.