Marco Secci

Amino-modified polystyrene nanoparticles affect signalling pathways of the sea urchin (Paracentrotus lividus) embryos

Abstract Polystyrene nanoparticles have been shown to pose serious risk to marine organisms including sea urchin embryos based on their surface properties and consequently behaviour in natural sea water. The aim of this study is to investigate the toxicity pathways of amino polystyrene nanoparticles (PS-NH2, 50 nm) in Paracentrotus lividus embryos in terms of development and signalling at both protein and gene levels. Two sub-lethal concentrations of 3 and 4 μg/mL of PS-NH2 were used to expose sea urchin embryos in natural sea water (PS-NH2 as aggregates of 143 ± 5 nm). At 24 and 48 h post-fertilisation (hpf) embryonic development was monitored and variations in the levels of key proteins involved in stress response and development (Hsp70, Hsp60, MnSOD, Phospho-p38 Mapk) as well as the modulation of target genes (Pl-Hsp70, Pl-Hsp60, Pl-Cytochrome b, Pl-p38 Mapk, Pl-Caspase 8, Pl-Univin) were measured. At 48 hpf various striking teratogenic effects were observed such as the occurrence of cells/masses randomly distributed, severe skeletal defects and delayed development. At 24 hpf a significant up-regulation of Pl-Hsp70, Pl-p38 Mapk, Pl-Univin and Pl-Cas8 genes was found, while at 48 hpf only for Pl-Univin was observed. Protein profile showed different patterns as a significant increase of Hsp70 and Hsp60 only after 48 hpf compared to controls. Conversely, P-p38 Mapk protein significantly increased at 24 hpf and decreased at 48 hpf. Our findings highlight that PS-NH2 are able to disrupt sea urchin embryos development by modulating protein and gene profile providing new understandings into the signalling pathways involved.

GC-ITMS analysis of PAH contamination levels in the marine sea urchin Paracentrotus lividus in Sardinia.

This paper describes the results of a two-year monitoring study examining the pollution of the sea urchin Paracentrotus lividus by polycyclic aromatic hydrocarbons (PAHs) in Sardinia. GC-ITMS analysis of sea urchin gonads showed the presence of 11 and 12 PAHs in the samples of Capo Pecora, and Capitana, respectively. Fluorene, naphthalene and its two degradation products, 1-methyl-naphthalene, and 2-methyl-naphthalene, were detected in all samples analyzed. The ΣPAH residues showed a similar trend over the two-year sampling period. Furthermore, the residues in the first year were slightly higher than in the second year. The information obtained by the multivariate statistical analysis PLS-DA allowed for the determination of samples based on field site and varying habitat types (rocky reef, and Posidonia seabed). The results of this study showed that Posidonia sea urchins are contaminated by high molecular weight PAHs and that Capitana samples are more contaminated due to a higher level of human activity in the area.

Physiologic Responses to Stress and Changes in Atlantic Bluefin Tuna (T. thynnus) Meat Color During Trap Fisheries Capture and Processing in Sardinia (W. Mediterranean)

This study investigated plasma cortisol, lactate, and glucose as descriptors of hematological stressors; while the RGB color model using the percentage of monochromatic channels Red (Rp), Green (Gp), and Blue (Bp) was used for the analysis of muscular tissue of the Atlantic bluefin tuna, Thunnus thynnus. The experimental design provided a comparison of stressors and color channels Before and After the stress state and the analysis of variability of monochromatic channels for Fresh and Frozen specimens collected at three time intervals. Results showed a rapid accumulation of cortisol levels (from 73.3 ± 9.5 to 148.0 ± 21.2 ng/mL), lactate (from 5.7 ± 2.9 to 17.0 ± 2.2 μmol/mL), and glucose (from 83.5 ± 8.0 to 128.6 ± 19.3 mg/dL; p < 0.05). The colorimetric analysis highlighted that this accumulation did not in fact affect the color variability of muscle. Analysis of variance carried out to test the effects of color variability in Fresh samples showed significant differences for Rp, Gp, and Bp channels (p < 0.05), whereas no differences were found in Frozen samples. Highly significant differences (p < 0.001) were found comparing Fresh and Frozen for Rp and Bp, indicating a drop of these channels under diverse treatments.