Specialized metabolites constitute a major antioxidant system involved in plant defence against environmental constraints, such as tropospheric ozone (O3). The objective of this experiment was to give a thorough description of the effects of an O3 pulse (120 ppb, 5 h) on the phenylpropanoid metabolism of sage, at both biochemical and molecular levels. Variable O3-induced changes were observed over time among the detected phenylpropanoid compounds (mostly identified as phenolic acids and flavonoids), likely because of their extraordinary functional diversity. Furthermore, decreases in the phenylalanine ammonia-lyase (PAL), phenol oxidase (PPO), and rosmarinic acid synthase (RAS) activities were reported during the first hours of treatment, probably due to an O3-induced oxidative damage to proteins. Both PAL and PPO activities were also suppressed at 24 h from the beginning of exposure, whereas enhanced RAS activity occurred at the end of treatment and at the recovery time, suggesting that specific branches of the phenolic pathways were activated. The increased RAS activity was accompanied by the up-regulation of the transcript levels of genes like RAS, tyrosine aminotransferase, and cinnamic acid 4-hydroxylase. In conclusion, sage faced the O3 pulse by regulating the activation of the phenolic biosynthetic route as an integrated defence mechanism.

Two fluorescent dyes (CT-tEPhA = 3,3',3''-(nitrilotris(benzene-4,1-diyl))tris(1-(thiophen-2-yl)prop-2-yn-1-one and T-tEPhA = tris(4-(thiophen-2-ylethynyl)phenyl)amine) have been synthesised and characterised in different solvents and in a poly(methyl methacrylate) (PMMA) matrix. In both cases, relatively high Stokes shifts (SS) and quantum yields (QY) have been displayed. Notably, CT-tEPhA based on a mild electron-attracting carbonyl group coupled with the electron-donating amino-centre, shows superior light emitting properties (higher SS, red-shifted emission, QY > 40%) suggesting application in light harvesting systems. Photocurrent measurements of CT-tEPhA/PMMA films yield a maximum optical efficiency of 6.32% that is greater than that of fluorophores with same emission window and comparable to that of red-emitting ones. This efficiency might be improved by extending the push-pull character of CT-tEPhA to cover the maximum efficiency of the Si-based PV cell. Nevertheless, these results clearly support the use of push-pull fluorophores based on the tris(4-ethynylphenyl)amine core in solar collectors.

The study of the interaction of persistent organic pollutants with biosubstrates helps to unravel the pathways for toxicity, however, few mechanistic data are present in the literature for these systems. We analyzed the binding of paraquat (PQ) and diquat (DQ) herbicides to natural calf thymus DNA and a DNA G-quadruplex by spectrophotometric titrations, ethidium bromide exchange tests, viscometry, and melting experiments. The interaction with bovine serum albumin (BSA) protein was studied spectrofluorimetrically at different temperatures. The retention of the targets on positive, negative, and neutral micellar aggregates and liposomes was analyzed by ultrafiltration experiments. Despite some favorable features, PQ and DQ only externally bind natural DNA and do not interact with DNA oligonucleotides. Both herbicides bind bovine serum albumin (BSA). PQ binds BSA mainly according to an electrostatics-driven process. However, ultrafiltration data also show that some hydrophobic contribution participates in the features of these systems. The practical problems related to unfavorable spectroscopic signals and inner filter effects are also discussed. Overall, both herbicides show a low affinity for nucleic acids and weak penetration into liposomes; in addition, the equilibrium constants values found for BSA system suggest optimal conditions for transport in the body.