Pyocyanin was the first natural phenazine described. The molecule is synthesized by about 95% of the strains of Pseudomonas aeruginosa. From discovery up to now, pyocyanin has been characterised by a very rich and avant-garde history, which includes its use in antimicrobial therapy, even before the discovery of penicillin opened the era of antibiotic therapy, as well as its use in electric current generation. Exhibiting an exuberant blue colour and being easy to obtain, this pigment is the subject of the present review, aiming to narrate its history as well as to unveil its mechanisms and suggest new horizons for applications in different areas of engineering, biology and biotechnology.
The cystic fibrosis transmembrane conductance regulator (CFTR) gene is influenced by the fundamental cellular processes like epithelial differentiation/polarization, regeneration and epithelial–mesenchymal transition. Defects in CFTR protein levels and/or function lead to decreased airway surface liquid layer facilitating microbial colonization and inflammation. The SERPINA1 gene, encoding alpha1-antitrypsin (AAT) protein, is one of the genes implicated in CF, however it remains unknown whether AAT has any influence on CFTR levels. In this study we assessed CFTR protein levels in primary human lung epithelial cells grown at the air-liquid-interface (ALI) alone or pre-incubated with AAT by Western blots and immunohistochemistry. Histological analysis of ALI inserts revealed CFTR- and AAT-positive cells but no AAT-CFTR co-localization. When 0.5 mg/mL of AAT was added to apical or basolateral compartments of pro-inflammatory activated ALI cultures, CFTR levels increased relative to activated ALIs. This finding suggests that AAT is CFTR-modulating protein, albeit its effects may depend on the concentration and the route of administration. Human lung epithelial ALI cultures provide a useful tool for studies in detail how AAT or other pharmaceuticals affect the levels and activity of CFTR.
Toxicological effects of zinc oxide nanoparticle exposure: an in vitro comparison between dry aerosol air-liquid interface and submerged exposure systems