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Both lacZ fusions with the lodAB promoter and quantitative reverse transcription-PCR (qRT-PCR) are utilized to demonstrate the role of the hybrid sensor histidine kinase PpoS in regulating lysine-[epsi]-oxidase (LOD) enzyme activity at the transcriptional level. The insights gained into the mechanisms regulating the synthesis of the antimicrobial protein lysine-[epsi]-oxidase in Marinomonas mediterranea could find significant application in the microbial colonization of the seagrass Posidonia oceanica.

Tannery wastewater is characterized by high and variable concentrations of diverse pollutants, which makes it difficult and costly to treat. In the search for sustainable treatment options for tannery effluents, two pilot-scale horizontal subsurface flow (HSF) constructed wetlands (CW) were built and operated for the treatment of synthetic water of quality similar to that of pre-treated tannery effluents. Five different loading phases were examined with gradual increase of inflow COD, NH4+-N and Cr loads until reaching and exceeding the typical composition of a tannery effluent. High COD and NH4+-N removals were observed (82 and 96%, respectively), and almost complete Cr removal in the outflow, which met the Venezuela national standards for environmental discharge. Plant uptake was measured, but microbial processes appear to be the main ammonium transformation/removal mechanism. Nitrogen, chlorophyll and Cr in the plant aerial parts and roots indicated the capacity of Phragmites sp. to grow and survive even under high loads. The measured heterotrophic bacteria in the substrate and rhizomes indicated the biofilm development and the oxidation of organic matter and nitrogen. Water losses via evapotraspiration were also measured and reached 14%. Overall, the tested CW design proved to be a sustainable and feasible alternative for the treatment of tannery wastewater in tropical climates. Image 109 • Two pilot constructed wetlands for tannery wastewater under tropical climate. • High COD and NH 4 +-N removal (82–96%), complete Cr removal (99%) was found. • Plants assimilate part of nitrogen load, microbial processes remove most of ammonia. • Native plant proved to be tolerant to applied high pollutant loads. • Higher heterotrophic bacteria in the substrate and rhizosphere than outflow. [ABSTRACT FROM AUTHOR]