Immunotoxicity of polystyrene nanoplastics in different hemocyte subpopulations of Mytilus galloprovincialis

Plastic represents 60-80% of litter in the ocean. Degradation of plastic to small fragments leads to the formation of microplastics (MPs <5mm) and nanoplastics (NPs <1 mu m). One of the most widely used and representative plastics found in the ocean is polystyrene (PS). Among marine organisms, the immune system of bivalves is recognized as suitable to assess nanomaterial toxicity. Hemocyte subpopulations [R1 (large granular cells), R2 (small semi-granular cells) and R3 (small agranular or hyaline cells)] of Mytilus galloprovincialis are specialized in particular tasks and functions. The authors propose to examine the effects of different sizes (50 nm, 100 nm and 1 mu m) PS NPs on the different immune cells of mussels when they were exposed to (1 and 10mg.L-1) of PS NPs. The most noteworthy results found in this work are: (i) 1 mu m PS NPs provoked higher immunological responses with respect to 50 and 100nm PS NPs, possibly related to the higher stability in size and shape in hemolymph serum, (ii) the R1 subpopulation was the most affected with respect to R2 and R3 concerning immunological responses and (iii) an increase in the release of toxic radicals, apoptotic signals, tracking of lysosomes and a decrease in phagocytic activity was found in R1

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions

Data to accompany manuscript: Time for righting in three species of sea urchins

Raw results of time for righting experiment in three sea urchins species from Patagonia and Antarctica performed in situ and in the labTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

The Caligus rogercresseyi miRNome: Discovery and transcriptome profiling during the sea lice ontogeny

Small RNA sequencing in the copepod ectoparasite Caligus rogercresseyi was conducted to evidence putative roles of non-coding RNAs during the sea louse ontogeny. Here, differentially expressed miRNAs and mRNAs for each developmental stage were analyzed in parallel with bioinformatic gene target predictions. Based on sequence analysis, C. rogercresseyi miRNome comprises 673 conserved miRNAs, including precursors, 5′ and 3′ isomiRs. The conserved miRNAs include 40 families found in twelve different arthropods species. The results also showed that C. rogercresseyi miRNome exhibit stage-specific expression patterns, with miRNA-996-4 and miRNA-124 displaying sex-biased expression. Target prediction of these miRNAs identifies possible silencing mechanism of sex-related genes. Furthermore, bantam isomiRs were highly transcribed during the infective stage of copepodid and target prediction using differentially expressed genes in Atlantic salmon infested with sea lice, suggests a putative role of these miRNAs in the host-pathogen interaction. This is the first study reporting a miRNA repertoire in a marine copepod ectoparasite that affects the salmon aquaculture worldwide