At the root of the wood wide web: self recognition an nonself incompatibility in mycorrhizal networks.

Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts living in the roots of 80% of land plant species, and developing extensive, below-ground extraradical hyphae fundamental for the uptake of soil nutrients and their transfer to host plants. Since AM fungi have a wide host range, they are able to colonize and interconnect contiguous plants by means of hyphae extending from one root system to another. Such hyphae may fuse due to the widespread occurrence of anastomoses, whose formation depends on a highly regulated mechanism of self recognition. Here, we examine evidences of self recognition and non-self incompatibility in hyphal networks formed by AM fungi and discuss recent results showing that the root systems of plants belonging to different species, genera and families may be connected by means of anastomosis formation between extraradical mycorrhizal networks, which can create indefinitely large numbers of belowground fungal linkages within plant communities

Quale insegnamento dalla "epopea" dell'amianto?

What lessons can be drawn from the “epic history” of asbestos? How this emblematic case can help the reflection on prevention in the workplace? The subjects of primary prevention, risk management, laws and regulation protecting safety and health in the workplace are discussed from different points of view, such as history of medicine, epidemiology, occupational and preventive medicine, labour law, organization theory, science methodology. These collected papers are aimed at proposing prevention strategies allowing to avoid mistakes and pitfalls like the ones that characterized the history of asbestos

Neustonic microplastics in the Southern Adriatic Sea. Preliminary results.

Neustonic micro-plastic abundance and polymeric composition were determined after a cruise conducted in the Southern Adriatic Sea between May 9th and 17th 2013. Plankton samples were collected using a Neuston net (200 µm mesh size) which sampled the first 50 cm of the sea surface at a speed of ~2 kts for 5-6 minutes. Samples were then stored in ethanol 70% and in the laboratory micro-plastics were hand-picked using a dissecting stereomicroscope, counted, weighed and split into 7 different size classes. On a subset of collected particles (> 0.7mm) FT-IR analyses were performed to characterize the polymeric composition of the items. All 29 surface tows contained plastic particles of various typologies (e.g. filaments, fragments, thin plastic films), colours and sizes. A total of 5940 plastic particles were collected during the survey, the vast majority of which were hard plastic fragments (78.5%) or synthetic fibers and filaments (19.2%). Most particles were white (27.8%), transparent (22.5%) or black/grey (21.4%). 98.2% of all the particles were < 5 mm and plastic abundance markedly increased with decreasing size (i.e. 52.8% of all the particles were smaller than 0.5 mm), indicating very high fragmentation rates. Overall, an average concentration of 1.05 ± 1.13 particles/m2 and 442.88 ± 1145.96 g/km2 was observed throughout the study area, with micro-plastic densities ranging from 0.10 particles/m2 to a maximum of 4.86 particles/m2. FT-IR analyses indicated polyethylene as the predominant polymer (41%), followed by polyester and paint (12%), polypropylene (10%), polystyrene and polyimide (5%), polyammide (3%), paraffin (4%) and 1% bioplastic (i.e. polycaprolactone). In addition, 7% of the items were characterized as non-plastic materials (i.e. minerals, cellulose and cotton fabric), suggesting a potential bias when visually sorting for micro-plastics. On the whole, very high levels of plastic pollution have been found in our study area. Despite any clear geographical pattern in plastic distribution was identified, the conspicuous spatial heterogeneity in plastic abundances and polymeric compositions seem to confirm the existence of multiple pollution sources insisting on the Adriatic Sea

Changes in soil aggregation and glomalin-related soil protein content as affected by the arbuscular mycorrhizal fungal species Glomus mosseae and Glomus intraradices.

Arbuscular mycorrhizal (AM) fungi are key organisms of the soil/plant system, influencing soil fertility and plant nutrition, and contributing to soil aggregation and soil structure stability by the combined action of extraradical hyphae and of an insoluble, hydrophobic proteinaceous substance named glomalin-related soil protein (GRSP). Since the GRSP extraction procedures have recently revealed problems related to co-extracting substances, the relationship between GRSP and AM fungi still remains to be verified. In this work the hypothesis that GRSP concentration is positively correlated with the occurrence of AM fungi was tested by using Medicago sativa plants inoculated with different isolates of Glomus mosseae and Glomus intraradices in a microcosm experiment. Our results show that (i) mycorrhizal establishment produced an increase in GRSP concentration – compared to initial values – in contrast with non-mycorrhizal plants, which did not produce any change; (ii) aggregate stability, evaluated as mean weight diameter (MWD) of macroaggregates of 1–2 mm diameter, was significantly higher in mycorrhizal soils compared to non-mycorrhizal soil; (iii) GRSP concentration and soil aggregate stability were positively correlated with mycorrhizal root volume and weakly correlated with total root volume; (iv) MWD values of soil aggregates were positively correlated with values of total hyphal length and hyphal density of the AM fungi utilized. The different ability of AM fungal isolates to affect GRSP concentration and to form extensive and dense mycelial networks, which may directly affect soil aggregates stability by hyphal enmeshment of soil particles, suggests the possibility of selecting the most efficient isolates to be utilized for soil quality improvement and land restoration programs

Ecotoxicological risk of microplastics for marine organisms

La presenza di Microplastiche (MP) negli oceani rappresenta una problematica emergente per l’ecosistema marino; è ormai stato dimostrato che le MP possono essere ingerire da diverse specie di organismi, ma non è stata ancora dimostrata la capacità di trasferimento trofico e di accumulo di queste microparticelle, e sono ancora molto carenti le informazioni sui effetti avversi indotti. In questo lavoro di ricerca, il ruolo di alcuni polimeri plastici, come vettori di inquinanti chimici, è stato inizialmente valutato su campioni di macro-plastiche vergini, macro- e micro-plastiche spiaggiate. Tramite esperimenti di laboratorio, sono state invece studiate sia le cinetiche di adsorbimento del pirene e del cadmio in MP di polietilene (PE) e polistirene (PS), che la loro capacità di trasferire i composti adsorbiti ai mitili, Mytilus galloprovincialis. In questi organismi esposti sono stati analizzati diversi effetti a livello molecolare, biochimico e cellulare, incluse le risposte immunologiche, le alterazioni lisosomiali, la proliferazione perossisomiale, le difese antiossidanti, gli effetti neurotossici, genotossici oltre che il profilo di espressione genica. E’ stato inoltre ottimizzato e applicato un nuovo protocollo per l'estrazione e caratterizzazione (FT-IR) delle MP su diverse specie di pesci e invertebrati del Mar Mediterraneo. I livelli di IPA maggiori sono stati misurati nelle micro e macro-plastiche spiaggiate, mentre un efficiente assorbimento delle sostanze chimiche è stato confermato, sia per il PE che PS, con una modalità di adsorbimento tempo e dose-dipendente. Indagini istologiche hanno rivelato la presenza di MP nell’emolinfa, nelle branchie e nei tessuti digestivi dei mitili. Gli IPA adsorbiti sono stati rilasciati dalle MP e accumulati nei tessuti dei mitili che hanno mostrato alterazioni di diversi biomarker sia molecolari che cellulari. Il protocollo di estrazione sviluppato ha permesso di dimostrare la presenza di MP nello stomaco e, per la prima volta, nel fegato di cefali esposti. Studi sul campo hanno evidenziato la presenza di particelle nel 38% degli organismi selvatici analizzati, con una maggior frequenza di MP sotto forma di frammenti e linee, costituiti preferenzialmente da PE, PS e nylon. In conclusione, questa tesi fornisce nuove informazioni sui rischi ecotossicologici delle MP per gli organismi marini oltre che un’importante linea di base sul livello di contaminazione da MP nel biota Mediterraneo.Microplastics (MPs) are a growing but still unexplored environmental concern for marine organisms. Although several species can ingest MPs, a clear evidence of their accumulation pathways, trophic transfer and adverse effects is still lacking. In this thesis, the potential role of MPs as vectors of chemical pollutants was initially evaluated in virgin macroplastics, beached macro- and microplastics; laboratory experiments further characterized adsorbing kinetics of pyrene and cadmium on polyethylene (PE) and polystyrene (PS) MPs, and their capability to transfer adsorbed pyrene to mussels Mytilus galloprovincialis. In these organisms, several molecular, biochemical and cellular effects were analyzed in term of immunological responses, lysosomal alterations, peroxisomal proliferation, antioxidant and neurotoxic effects, genotoxicity and gene expression profile. A new protocol for extraction and FT-IR characterization of MPs in marine organisms was optimized and applied to several species of Mediterranean fish and invertebrates. Load of PAHs was higher in weathered and micron-sized particles, and an efficient adsorption of chemicals was confirmed with a time- and dose-dependent trend for both PE and PS. Histological analyses revealed occurrence of ingested MPs in haemolymph, gills and digestive tissues of mussels. Adsorbed PAHs were desorbed from MPs and bioavailable for mussels that showed many altered several molecular and cellular biomarkers. The developed extraction protocol allowed to demonstrate the presence of MPs in the stomach and, for the first time, in liver of exposed Mugil cephalus. Field studies highlighted the occurrence of MPs in 38% of analyzed wild organisms, mostly represented by fragments and lines, while PE, PS and nylon were the dominant polymers. In conclusion, this thesis provides new insights on the ecotoxicological risks of MPs for marine organisms and an important baseline for assessing the level of MPs contamination in Mediterranean biot

Ecotoxicological effects of chemical contaminants adsorbed to microplastics in the clam Scrobicularia plana

Although microplastics (MPs) are distributed globally in the marine environment, a great deal of unknowns relating to their ecotoxicological effects on the marine biota remains. Due to their lipophilic nature, microplastics have the potential to adsorb persistent organic pollutants present in contaminated regions, which may increase their detrimental impact once assimilated by organisms. This study investigates the ecotoxicological effects of exposure to low-density polyethylene (LDPE) microplastics (11-13 beta m), with and without adsorbed contaminants (benzo[a]pyrene- BaP and perfluorooctane sulfonic acid-PFOS), in the peppery furrow shell clam, Scrobicularia plana. Environmentally relevant concentrations of contaminants (BaP-16.87 +/- 0.22 mu g g(-1) and PFOS-70.22 +/- 12.41 mu g g(-1)) were adsorbed to microplastics to evaluate the potential role of plastic particles as a source of chemical contamination once ingested. S. plana were exposed to microplastics, at a concentration of 1 mg L-1, in a water-sediment exposure setup for 14 days. Clams were sampled at the beginning of the experiment (day 0) and after 3, 7, and 14 days. BaP accumulation, in whole clam tissues, was analyzed. A multi-biomarker assessment was conducted in the gills, digestive gland, and haemolymph of clams to clarify the effects of exposure. This included the quantification of antioxidant (superoxide dismutase, catalase, glutathione peroxidase) and biotransformation (glutathione-Stransferases) enzyme activities, oxidative damage (lipid peroxidation levels), genotoxicity (single and double strand DNA breaks), and neurotoxicity (acetylcholinesterase activity). Results suggest a potential mechanical injury of gills caused by ingestion of microplastics that may also affect the analyzed biomarkers. The digestive gland seems less affected by mechanical damage caused by virgin microplastic exposure, with the MPs-adsorbed BaP and PFOS exerting a negative influence over the assessed biomarkers in this tissue.JPI Oceans FCT JPIOCEANS/0005/2015 JPI Oceans (BELSPO) JPI Oceans (FWO) JPI Oceans (FORMAS) JPI Oceans (SwAM) FCT UID/MAR/00350/2013info:eu-repo/semantics/publishedVersio

Microplastics as Vectors for Environmental Contaminants : Exploring Sorption, Desorption, and Transfer to Biota

The occurrence and effects of microplastics (MPs) in the aquatic environment are receiving increasing attention. In addition to their possible direct adverse effects on biota, the potential role of MPs as vectors for hydrophobic organic chemicals (HOCs), compared to natural pathways, is a topic of much debate. It is evident, however, that temporal and spatial variations of MP occurrence do (and will) occur. To further improve the estimations of the role of MPs as vectors for HOC transfer into biota under varying MP concentrations and environmental conditions, it is important to identify and understand the governing processes. Here, we explore HOC sorption to and desorption from MPs and the underlying principles for their interactions. We discuss intrinsic and extrinsic parameters influencing these processes and focus on the importance of the exposure route for diffusive mass transfer. Also, we outline research needed to fill knowledge gaps and improve model-based calculations of MP-facilitated HOC transfer in the environment. Integr Environ Assess Manag 2017;13:488–493. © 2017 SETA