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Pseudomonas aeruginosa has been amongst the top 10 'superbugs' worldwide and is causing infections with poor outcomes in both humans and animals. From 202 P. aeruginosa isolates (n = 121 animal and n = 81 human), 40 were selected on the basis of biofilm-forming ability and were comparatively characterized in terms of virulence determinants to the type strain P. aeruginosa PAO1. Biofilm formation, pyocyanin and hemolysin production, and bacterial motility patterns were compared with the ability to kill human cell line A549 in vitro. On average, there was no significant difference between levels of animal and human cytotoxicity, while human isolates produced higher amounts of pyocyanin, hemolysins and showed increased swimming ability. Non-parametric statistical analysis identified the highest positive correlation between hemolysis and the swarming ability. For the first time an ensemble machine learning approach used on the in vitro virulence data determined the highest relative predictive importance of the submerged biofilm formation for the cytotoxicity, as an indicator of the infection ability. The findings from the in vitro study were validated in vivo using zebrafish (Danio rerio) embryos. This study highlighted no major differences between P. aeruginosa species isolated from animal and human infections and the importance of pyocyanin production in cytotoxicity and infection ability.

Laccases are multicopper-oxidases with variety of biotechnological applications. While predominantly used, fungal laccases have limitations such as narrow pH and temperature range and their production via heterologous protein expression is more complex due to posttranslational modifications. In comparison, bacterial enzymes, including laccases, usually possess higher thermal and pH stability, and are more suitable for expression and genetic manipulations in bacterial expression hosts. Therefore, the aim of this study was to identify, recombinantly express, and characterize novel laccases from Pseudomonas spp. A combination of approaches including DNA sequence analysis, N-terminal protein sequencing, and genome sequencing data analysis for laccase amplification, cloning, and overexpression have been used. Four active recombinant laccases were obtained, one each from P. putida KT2440 and P. putida CA-3, and two from P. putida F6. The new laccases exhibited broad temperature and pH range and high thermal stability, as well as the potential to degrade selection of synthetic textile dyes. The best performing laccase was CopA from P. putida F6 which degraded five out of seven tested dyes, including Amido Black 10B, Brom Cresol Purple, Evans Blue, Reactive Black 5, and Remazol Brilliant Blue. This work highlighted species of Pseudomonas genus as still being good sources of biocatalytically relevant enzymes. most laccases, especially bacterial forms [12]. The presence of different metal ions can affect laccase activity, either inducing or suppressing it. Metal ions such as Cu +2 , Ca +2 , Ni +2 , Co +2 , and Mn +2 are generally known to accelerate laccase activity at a remarkable level [13].Due to broad substrate spectrum, laccases have become very attractive for a variety of biotechnological and industrial applications such as organic synthesis; lignin degradation; and bio-product formation for the food, textile, and pharmaceutical industries; remediation of contaminated environments; as well as construction of biosensors and biofuel cells [14][15][16]. During the last decade laccases have been used in decolorization and detoxification of textile effluents [17]. Effluents from the textile industry are usually complex, containing a wide variety of synthetic dyes [18], among which the most common are azo dyes, anthraquinone, triphenylmethane, and indigo dyes [19].In the recent years, development of high-performance recombinant bacterial strains and the possibility of increasing the production of recombinant proteins created new opportunities for the commercial use of laccases, since the production from wild type strains has limitations in growth and product yield, which are not suitable for standard industrial fermentations [20]. The majority of studies on laccases are focused on laccases originated from fungi. Having in mind that industrial processes often require high temperature and pressure, or extremely acidic or alkaline pH, fungal laccases are not the best candidates for such industrial applications since they oper...

Silver(i) complexes with pyridine-4,5-dicarboxylates show significant activity against clinical isolates from the milk of a cow diagnosed with mastitis.