Does salinity variation increase synergistic effects of triclosan and carbon nanotubes on Mytilus galloprovincialis? Responses on adult tissues and sperms

The use of carbon nanotubes (CNTs) is rapidly increasing and several scientific studies have addressed their toxicological properties. However, only a very small number of publications have deal with the interaction between CNTs and other molecules. Triclosan (TCS) is an antibacterial agent used in personal care and household products. Commonly detected in aquatic ecosystems, there is a strong evidence that aquatic biota is sensitive to this compound. Aside from emergent pollutants, aquatic organisms are continuously subjected to abiotic variations including salinities. Therefore, the main goal of the present study was to better understand how physio-chemical interactions of CNTs with TCS under different salinity levels (37, 28 and 19) affect the mussel species Mytilus galloprovincialis through the evaluation of biochemical alterations on gametes (sperms) and adult tissues, providing more ecologically relevant information on organisms' responses. The results showed toxicological effects in terms of sperm metabolic activity and intracellular reactive oxygen species production as well as cellular damage and alteration of metabolic capacity at the adult's stage when exposed to both contaminants acting alone and in combination, under tested salinities. Moreover, when the mussels were exposed to the combination of both contaminants, they showed major toxic impacts on both assessed biological levels (adult tissues and sperms) especially under control salinity. This suggests that toxicity upon mixture exposure compared to single-substance exposure may impair mussels' populations, affecting reproduction success and growth.publishe

The Culturable Mycobiota of Sediments and Associated Microplastics: From a Harbor to a Marine Protected Area, a Comparative Study

Fungi are an essential component of marine ecosystems, although little is known about their global distribution and underwater diversity, especially in sediments. Microplastics (MPs) are widespread contaminants worldwide and threaten the organisms present in the oceans. In this study, we investigated the fungal abundance and diversity in sediments, as well as the MPs, of three sites with different anthropogenic impacts in the Mediterranean Sea: the harbor of Livorno, the marine protected area "Secche della Meloria"; and an intermediate point, respectively. A total of 1526 isolates were cultured and identified using a polyphasic approach. For many of the fungal species this is the first record in a marine environment. A comparison with the mycobiota associated with the sediments and MPs underlined a "substrate specificity", highlighting the complexity of MP-associated fungal assemblages, potentially leading to altered microbial activities and hence changes in ecosystem functions. A further driving force that acts on the fungal communities associated with sediments and MPs is sampling sites with different anthropogenic impacts

Il serpulide Ficopomatus enigmaticus (Fauvel, 1923) come organismo modello per test ecotossicologici

Ficopomatus enigmaticus [Favel, 1923] è un polichete serpulide di origine incerta, a vita sessile capace di costruire grandi colonie calcaree. E’ una specie diffusa in zone tropicali e temperate, tipica di acque salmastre come ambienti estuarili e lagunari. E’ una specie molto comune lungo i litorali italiani, il motivo di una così vasta diffusione come specie aliena è probabilmente da riferirsi alla sua naturale resistenza ad ampie variazioni di temperatura (tra 0° - 35° C), pH (tra 4 - 9) e salinità (5 - 55psu), può quindi comparire in ambienti portuali, lagunari e in zone interessate dall’apporto di acque dolci. L’optimum per la riproduzione si ha ad una salinità compresa tra 10-35psu e una temperatura non più alta di 18°C. F. enigmaticus è una specie dioica a fecondazione esterna, il ciclo riproduttivo dura circa 30 giorni e inizia con la produzione di larve planctoniche planctotrofiche (trocofore). Una volta raggiunto lo stadio di larva competente si insediano sul substrato dove raggiungono la maturità sessuale. Grazie a queste caratteristiche F. enigmaticus potrebbe essere un ottimo candidato come organismo modello per test ecotossicologici sia di acque marine che salmastre. I principali punti di forza sono rappresentati da: • ampia valenza ecologica, che si traduce in una resistenza ad ampie variazioni delle condizioni ambientali (salinità, temperatura, pH); • ampia distribuzione in tutto il bacino del Mediterraneo, pur non essendo una specie endemica; • facile reperibilità degli organismi, che colonizzano ambienti facilmente accessibili (moli, banchine portuali, ecc.); • possibilità di stabulazione in laboratorio; • rapidità di esecuzione del saggio (24-48 h); • ciclo vitale relativamente breve (20-30 gg); • emissione dei gameti tutto l'anno; • possibilità di compensare la carenza di rappresentatività dei policheti, e degli anellidi in generale, in materia di saggi biologici. A tale scopo sono stati condotti saggi ecotossicologici su spermi (test di spermiotossicità) ed embrioni (test di sviluppo larvale) con quattro tossici di riferimento rappresentati da rame, cadmio, sodio dodecilsolfato (SDS) e 4-n-nonilfenolo (NP), utilizzando come endpoint la percentuale di uova fecondate nel primo caso e la percentuale di sviluppo larvale corretto (trocofora correttamente sviluppata) nell’ ultimo caso. E' stato inoltre valutato l'effetto della salinità (5-10-15-30psu) alle diverse condizioni. Per ogni sostanza di riferimento, ad ogni salinità selezionata, è stato valutato il parametro ecotossicologico EC50 ed i valori ottenuti sono stati poi confrontati con i dati di letteratura ottenuti con differenti organismi (es. Paracentrotus lividus, Hydroides elegans) ai fini di una valutazione comparativa della sensibilità del test ai tossici impiegati

Suitability of cholinesterase of polychaete Diopatra neapolitana as biomarker of exposure to pesticides: In vitro characterization

Cholinesterases of Diopatra neapolitana were characterized for their activity in whole body and different body segments (apical, intermediate, posterior), substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, isoOMPA, BW284C51) and carbamates (carbofuran, methomyl, aldicarb and carbaryl). Results showed that the rate of hydrolysis for acetyl- and propionylthiocholine was higher in the posterior segment than the apical/intermediate segments and whole body. Cholinesterases of D. neapolitana showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was poorly hydrolyzed indicating, together with the absence of inhibition by the specific inhibitor and the absence of reactive bands in native electrophoresis, a lack of an active butyrylcholinesterase, differently than that observed in other Annelida species. The degree of inhibition by selected carbamates of cholinesterase activity with propionylthiocholine as substrate was higher than that observed with ATChI-ChE activity; aldicarb showed the highest inhibitory effect

CHARACTERIZATION OF CHOLINESTERASES IN THE POLYCHAETE DIOPATRA NEAPOLITANA

Cholinesterases of Diopatra neapolitana were characterized for their activity in whole body and different body segments (apical, intermediate, posterior), substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51) and carbamates (carbofuran, methomyl, aldicarb and carbaryl). Results showed that the rate of hydrolysis for acetyl- and propionylthiocholine was higher in the posterior segment than the apical/intermediate segments and whole body. Cholinesterases of D. neapolitana showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was poorly hydrolyzed indicating, together with the absence of inhibition by the specific inhibitor and the absence of reactive bands in native electrophoresis, a lack of an active butyrylcholinesterase, differently than that observed in other Annelida. The degree of inhibition by selected carbamates of cholinesterase activity with propionylthiocholine as substrate resulted higher than that observed with ATChI-ChE activity; aldicarb showed the highest inhibitory effect

The serpulid Ficopomatus enigmaticus (Fauvel, 1923) as candidate organisms for ecotoxicological assays in brackish and marine waters

Ficopomatus enigmaticus is an ubiquitous fouling reef-forming species, easy to sample and recognize, diecious with gamete spawning along different seasons in different salinity conditions. Due to its characteristics it could become a good candidate for the monitoring of both marine and brackish waters. The suitability of F. enigmaticus as a promising model organism in ecotoxicological bioassays was evaluated by a sperm toxicity and a larval development assay. The fertilization rate in different salinity conditions (range 5-35‰) was first assessed in order to detect the salinity threshold within which profitably perform the assays. Afterward copper (Cu2+), cadmium (Cd2+), sodium dodecyl sulfate (SDS) and 4-n-nonylphenol (NP) were used as reference toxicants in exposure experiments with spermatozoids (sperm toxicity assay) and zygotes (larval development assay). A dose-response effect was obtained for all tested toxicants along all salinity conditions except for 5‰ salinity condition where a too low (<30%) fertilization rate was observed. NP showed the highest degree of toxicity both in sperm toxicity and larval development assay. In some cases the results, expressed as EC50 values at 35‰ salinity condition, were similar to those observed in the literature for marine organisms such as the sea urchin (Paracentrotus lividus) and the marine serpulid Hydroides elegans, while the exposure of F. enigmaticus spermatozoids' to Cd2+ and NP resulted in toxicity effects several orders of magnitude higher than observed in P. lividus. Spermatozoids resulted to be slightly more sensitive then zygotes to all different toxicants

Soluble esterases as biomarkers of neurotoxic compounds in the widespread serpulid Ficopomatus enigmaticus (Fauvel, 1923)

The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in Ficopomatus enigmaticus as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of F. enigmaticus were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and in vitro response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from F. enigmaticus showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. In vitro data highlighted the presence of active forms of ChEs and CEs in F. enigmaticus that could potentially be inhibited by pesticides at environmentally relevant concentration.publishe

Adding functions to marine infrastructure: Pollutant accumulation, physiological and microbiome changes in sponges attached to floating pontoons inside marinas

The rate of introduction of man-made habitats in coastal environments is growing at an unprecedented pace, as a consequence of the expansion of urban areas. Floating installations, due to their unique hydrodynamic features, are able to provide great opportunities for enhancing water detoxification through the use of sessile, filtering organisms. We assessed whether the application of sponges to floating pontoons could function as a tool for biomonitoring organic and inorganic pollutants and for improving water quality inside a moderately contaminated marina in the NW Mediterranean. Fragments of two common Mediterranean sponges (Petrosia (Petrosia) ficiformis and Ircinia oros) were fixed to either suspended natural fibre nets beneath a floating pontoon or to metal frames deployed on the sea bottom. We assessed the accumulation of organic and inorganic contaminants in sponge fragments and, in order to provide an insight into their health status, we examined changes in their metabolic and oxidative stress responses and associated microbiomes. Fragments of both sponge species filtered out pollutants from seawater on both support types, but generally showed a better physiological and metabolic status when fixed to nets underneath the pontoon than to bottom frames. P. (P) ficiformis maintained a more efficient metabolism and exhibited a lower physiological stress levels and higher stability of the associated microbiome in comparison with I. oros. Our study suggests that the application of sponges to floating pontoon represents a promising nature-based solution to improve the ecological value of urban environments