Nanomaterials are revolutionizing the field of medicine to improve the quality of life due to the myriad of applications stemming from their unique properties, including the antimicrobial activity against pathogens. In this study, the antimicrobial and antibiofilm properties of a novel nanomaterial composed by zinc oxide nanorods-decorated graphene nanoplatelets (ZNGs) are investigated. ZNGs were produced by hydrothermal method and characterized through field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. The antimicrobial activity of ZNGs was evaluated against Streptococcus mutans, the main bacteriological agent in the etiology of dental caries. Cell viability assay demonstrated that ZNGs exerted a strikingly high killing effect on S. mutans cells in a dose-dependent manner. Moreover, FE-SEM analysis revealed relevant mechanical damages exerted by ZNGs at the cell surface of this dental pathogen rather than reactive oxygen species (ROS) generation. In addition, inductively coupled plasma mass spectrometry (ICP-MS) measurements showed negligible zinc dissolution, demonstrating that zinc ion release in the suspension is not associated with the high cell mortality rate. Finally, our data indicated that also S. mutans biofilm formation was affected by the presence of graphene-zinc oxide (ZnO) based material, as witnessed by the safranin staining and growth curve analysis. Therefore, ZNGs can be a remarkable nanobactericide against one of the main dental pathogens. The potential applications in dental care and therapy are very promising.

The Anthropocene is characterized by dramatic ecosystem changes driven by human activities. The impact of these activities can be assessed by different geochemical and paleontological proxies. However, each of these proxies provides only a fragmentary insight into the effects of anthropogenic impacts. It is highly challenging to reconstruct, with a holistic view, the state of the ecosystems from the preindustrial period to the present day, covering all biological components, from prokaryotes to multicellular eukaryotes. Here, we used sedimentary ancient DNA (sedaDNA) archives encompassing all trophic levels of biodiversity to reconstruct the two century-natural history in Bagnoli-Coroglio (Gulf of Pozzuoli, Tyrrhenian Sea), one of the most polluted marine-coastal sites in Europe. The site was characterized by seagrass meadows and high eukaryotic diversity until the beginning of the 20th century. Then, the ecosystem completely changed, with seagrasses and associated fauna as well as diverse groups of planktonic and benthic protists being replaced by low diversity biota dominated by dinophyceans and infaunal metazoan species. The sedaDNA analysis revealed a five-phase evolution of the area, where changes appear as the result of a multi-level cascade effect of impacts associated with industrial activities, urbanization, water circulation and land-use changes. The sedaDNA allowed to infer reference conditions that must be considered when restoration actions are to be implemented.

Surface sediments from Khnifiss lagoon (Morocco) were analyzed to evaluate the contamination degree of the area. Concentrations of V, Cr, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb were determined on samples taken during the summer and the autumn of 2016. On the whole, higher concentrations were found in the summer season. The results revealed the following average concentrations (mg/kg), reported in descending order: Zn (51.7 ± 31.3) > V (38.8 ± 24.7) > Cr (26.6 ± 17.8) > Ni (16.5 ± 5.47) > As (8.50 ± 2.00) > Cu (6.60 ± 3.81) > Pb (6.13 ± 3.46) > Co (3.57 ± 2.09) > Cd (0.16 ± 0.11) > Hg (0.006 ± 0.001). Organic matter showed a positive significant correlation with some trace metals (mainly V, Cr, Co, Zn, Cd, Pb). Three pollution indices were calculated: Enrichment Factor (EF), Index of Geo−accumulation (Igeo), and Pollution Load Index (PLI). Minimal enrichments (for Zn, As, and Cd) were detected at some sampling points. Overall indices showed that the Khnifiss sediments can be classified as not contaminated, and that the trace metals amounts found are ascribable to the geogenic origin. The results of this work can be used as a starting point for further evaluations of trace metals distribution in Moroccan lagoons.

In this investigation, the crystal chemical characterization of one sample of woolly erionite-K (Lander County, NV, USA) was examined after suspension in a FeCl₂ solution, in anaerobic conditions. The aim of this study was to determine the effect of the chemical composition of erionite on its efficiency to bind iron. Inductively coupled plasma (ICP) results showed that the sample bound Fe(II) through an ion-exchange mechanism mainly involving Ca. In addition, chemical and structural data indicated that Fe(II) is fixed at the Ca3 site, six-fold coordinated to water molecules. According to Brunauer–Emmett–Teller (BET) sample surface area the amount of Fe(II) bound by the fibers was comparable with that retrieved for fibrous erionite-Na sample from Rome (OR, USA) for which the ion-exchange process mainly affected Na. This finding provides clear evidence of a strong tendency of Fe(II) to bind to the erionite structure. Furthermore, considering that the woolly erionite-K from Langer County differs markedly from erionite-Na from Rome in the extra-framework cation content, our observations indicate that the Fe binding efficiency is not significantly modulated by the chemical composition. Notably, Fe ion-exchanged and/or accumulated on the fiber surface can generate hydroxyl radicals via the Fenton reaction, thus influencing the potential carcinogenicity of the different erionite species.