Nanoplastic debris, resulted from runoff and weathering breakdown of macro- and microplastics, represents an emerging concern for marine ecosystems. The aim of the present study was to investigate disposition and toxicity of polystyrene nanoparticles (NPs) in early development of sea urchin embryos (Paracentrotus lividus). NPs with two different surface charges where chosen, carboxylated (PS-COOH) and amine (PS-NH2) polystyrene, the latter being a less common variant, known to induce cell death in several in vitro cell systems. NPs stability in natural seawater (NSW) was measured while disposition and embryotoxicity were monitored within 48 h of postfertilization (hpf). Modulation of genes involved in cellular stress response (cas8, 14-3-3ε, p-38 MAPK, Abcb1, Abcc5) was investigated. PS-COOH forms microaggregates (PDI > 0.4) in NSW, whereas PS-NH2 results are better dispersed (89 ± 2 nm) initially, though they also aggregated partially with time. Their respectively anionic and cationic nature was confirmed by ζ-potential measurements. No embryotoxicity was observed for PS-COOH up to 50 μg mL(-1) whereas PS-NH2 caused severe developmental defects (EC50 3.85 μg mL(-1) 24 hpf and EC50 2.61 μg mL(-1) 48 hpf). PS-COOH accumulated inside embryo's digestive tract while PS-NH2 were more dispersed. Abcb1 gene resulted up-regulated at 48 hpf by PS-COOH whereas PS-NH2 induced cas8 gene at 24 hpf, suggesting an apoptotic pathway. In line with the results obtained with the same PS NPs in several human cell lines, also in sea urchin embryos, differences in surface charges and aggregation in seawater strongly affect their embryotoxicity.

We applied independent species concepts to clarify the phylogeographic structure of the ascidian Ciona intestinalis, a powerful model system in chordate biology and for comparative genomic studies. Intensive research with this marine invertebrate is based on the assumption that natural populations globally belong to a single species. Therefore, understanding the true taxonomic classification may have implications for experimental design and data management. Phylogenies inferred from mitochondrial and nuclear DNA markers accredit the existence of two cryptic species: C. intestinalis sp. A, genetically homogeneous, distributed in the Mediterranean, northeast Atlantic, and Pacific, and C. intestinalis sp. B, geographically structured and encountered in the North Atlantic. Species-level divergence is further entailed by crossbreeding estimates. C. intestinalis A and B from allopatric populations cross-fertilize, but hybrids remain infertile because of defective gametogenesis. Although anatomy illustrates an overall interspecific similarity lacking in diagnostic features, we provide consistent tools for in-field and in-laboratory species discrimination. Finding of two cryptic taxa in C. intestinalis raises interest in a new tunicate genome as a gateway to studies in speciation and ecological adaptation of chordates.anatomy ͉ Ciona intestinalis ͉ cryptic species ͉ gamete compatibility ͉ phylogenetics

Astaxanthin is a carotenoid with powerful antioxidant and anti-inflammatory activity produced by several freshwater and marine microorganisms, including bacteria, yeast, fungi, and microalgae. Due to its deep red-orange color it confers a reddish hue to the flesh of salmon, shrimps, lobsters, and crayfish that feed on astaxanthin-producing organisms, which helps protect their immune system and increase their fertility. From the nutritional point of view, astaxanthin is considered one of the strongest antioxidants in nature, due to its high scavenging potential of free radicals in the human body. Recently, astaxanthin is also receiving attention for its effect on the prevention or co-treatment of neurological pathologies, including Alzheimer and Parkinson diseases. In this review, we focus on the neuroprotective properties of astaxanthin and explore the underlying mechanisms to counteract neurological diseases, mainly based on its capability to cross the blood-brain barrier and its oxidative, anti-inflammatory, and anti-apoptotic properties.

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