Thermodynamic analysis of POPs interaction with biosubstrates

Persistent organic pollutants (POPs) as polycyclic aromatic hydrocarbons (PAH), pesticides and herbicides are nowadays ubiquitous [1]. These species are highly lipophilic and all at least suspected of carcinogenic effects [2,3]. However, information on their toxic activity is often related to in vitro/in vivo studies, whereas a detailed analysis of the mechanistic/chemical aspects of the binding to biosubstrates is sometimes missing. To contribute to this field and in the frame of our participation to PNRA (National Antarctic Research Program) we have done some tests on the binding of model targets (two PAHs, two pesticides and two herbicides, Fig. 1) to biosubstrates (natural DNA and bovine serum albumin - BSA). The interaction with micelles and liposomes was also tested, both as to scale the lipophilicity and to get information on the possible accumulation on membranes. The results collected show that the high hydrophobicity of these species turns into very high affinity for DNA. Absorbance and fluorescence titrations suggest complex binding modes that are discussed in relation with the different pollutant/DNA ratio. BSA binding is also found to occur. Ultrafiltration coupled with absorbance spectroscopy enables the percentage of retention (R%) on the micelle/liposome be measured. R% dependence on the molecule and on the type of system (sodium dodecyl sulphate anionic micelles, TritonX-100 neutral micelles, dodecyl trimethyl ammonium chloride positive micelles and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes) is discussed. References: [1] A. Lo Giudice, P. Casella, V. Bruni, L. Michaud, Ecotoxicology 2013, 22, 240-250. [2] H. Yu, Journal of Enviromental Science and Health 2002, 20, 149-183. [3] M.C.R. Alavanja, M.R. Bonner, Journal of Toxicology and Environmental Health B 2012, 15, 238-263

Paraquat e diquat: diffusione in campioni reali ed interazione con biosubstrati di due erbicidi vietati ma con pericolo di persistenza

Il paraquat (PQ) ed il diquat (DQ) sono due erbicidi ampiamente impiegati nel nostro territorio fino alla loro messa al bando da parte della Comunità Europea nel 2007 per il paraquat e nel 2018 per il diquat, quando l’elevata esposizione a tali erbicidi è stata collegata a patologie di insufficienza respiratoria acuta e all’aumentato insorgere del Morbo di Parkinson.Da un punto di vista ambientale, l’analisi della loro persistenza ha purtroppo mostrato come paraquat e diquat ancora siano presenti nelle acque e nel suolo. Da un punto di vista di meccanismo di tossicità, esistono studi in letteratura di interazione con biosubstrati che però fondamentalmente sono limitati al sistema paraquat/DNA. Il presente lavoro nasce dalla nostra partecipazione al National Antarctic Research Program (PNRA) e si sviluppa su due obiettivi. Uno di essi è valutare le interazioni dei due erbicidi con biosubstrati naturali e approfondire lo studio della loro tossicità misurandone la tendenza ad essere adsorbiti su sistemi micellari e liposomi di diversa natura, i quali rappresentano un modello semplificato di membrane biologiche. L’altro è quello di mettere a punto e validare un metodo analitico GC-MS per l’identificazione e quantificazione dei due erbicidi in campioni acquosi reali provenienti dal nostro territorio, per verificare la eventuale presenza persistente di paraquat e diquat nel territorio pisano

Tris-Ethynylphenyl-amine Fluorophores: Synthesis, Characterisation and Test of Performances in Luminescent Solar Concentrators

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 biosynthesis of phenolic compounds is an integrated defence mechanism to prevent ozone injury in Salvia officinalis

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 upregulation 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

Xenotransplantation of pre-pubertal ovarian cortex and prevention of follicle depletion with anti-Müllerian hormone (AMH)

Objective: To determine whether recombinant AMH (rAMH) could prevent post-transplant follicular depletion by acting on the stemness markers Oct-4, Sox2, and NANOG. Materials and methods: This was an experimental study where 12 ovariectomized nude mice were xenotransplanted with vitrified/warmed ovarian cortex obtained from a pre-pubertal girl and Alzet pumps delivering rAMH, or placebo (control), were inserted intra-abdominally. Previously vitrified/warmed ovarian cortex fragments were transplanted after 7 days and then harvested after 14 days from pump placement. We performed real-time RT-PCR analyses, ELISA for AMH, FSH, and estradiol, histologic measurement of ovarian follicles, and immunohistochemistry for Ki67 and TUNEL. The main outcome measures were serum levels and tissue expression of the parameters under investigation and follicle count. Results: Serum AMH, FSH, and estradiol reflected post-ovariectomy profiles and were mildly influenced by rAMH administration. Ovarian cortex expression of AMH, AMH-R2, VEGF, GDF9, Oct-4, and Sox2 was lower in rAMH mice than in controls, while NANOG was upregulated. There was a non-significant decrease in primordial follicles after vitrification-warming, and xenotransplantation further decreased this number. There were lower cell replication and depressed apoptosis in the rAMH group. Conclusions: Administration of recombinant AMH in the peri-transplant period did not protect the initial follicular depletion but decreased apoptosis and cellular activation and regulated stem cell markers\u27 tissue expression. These results aid our understanding of the inhibitory effects of AMH on follicular development and show the benefit of administering exogenous AMH at the time of pre-pubertal ovarian cortex transplant to protect the follicles from pre-activation and premature depletion