Electrolites and Heavy Metals in Coelomic Fluid of Sea Urchin, Arbacia lixula from Adriatic Sea: Biochemical Approach to Ecotoxicological Study

Abstract

The main circulatory medium of echinoderms is the coelomic fluid. Biochemistry of coelomic fluid is very complex and slightly different from seawater. The main aim of this research was to analyse concentration of electrolytes (potassium, calcium, magnesium, chlorine and sodium), heavy metals (lead, chromium, cadmium and cobalt) and iron in coelomic fluid of sea urchin, Arbacia lixula as an indirect indicator of seawater contamination. After precise statistical evaluation it was observed that electrolyte concentrations were; Na 189.20±11.41 mmol/l, Cl 134.06±37.08 mmol/l, Mg 4.24±1.08 mmol/l, Ca 3.04±0.84 mmol/l. Biochemical content of heavy metals in coelomic fluid was; Co 1.292±0.879 ppm, Pb 0.644±0.131 ppm, Cr 0.116±0.055 ppm, Cd 0.031±0.017 ppm and iron 0.259±0.058 ppm, and it depends on the potential accumulation level in the organism. The composition of electrolyte and heavy metal content varies depending on the composition of seawater. Obtained values are within the range of values most commonly found in low polluted areas of the Adriatic sea. Similar models may be applied for monitoring of heavy metal contamination in marine environment. Na 189.20±11.41 mmol/l, Cl 134.06±37.08 mmol/l, Mg 4.24±1.08 mmol/l, Ca 3.04±0.84 mmol/l). Biokemijski sadržaj teških metala je iznosio (Co 1.292±0.879 ppm, Pb 0.644±0.131 ppm, Cr 0.116±0.055 ppm, Cd 0.031±0.017 ppm) i željeza 0.259±0.058 ppm, te je ovisio o stupnju akumulacije u Sažetak Glavni cirkulatorni medij bodljokožaca je celomska tekućina. Celomska tekućina ima složen sastav i različita je od sastava morske vode. Glavni cilj ovog istraživanja bio je analiza koncentracije elektrolita (kalija, kalcija, magnezija, klorida i natrija), teških metala (olova, kroma, kadmija i kobalta) i željeza u celomskoj tekućini morskog ježinca Arbacia lixula, kao neizravnih indikatora onečišćenja morske vode. Nakon precizne statističke analize utvrđeno je da su koncentracije elektrolita iznosile ( organizmu. Sastav celomske tekućine u pogledu koncentracije elektrolita i teških metala varira ovisno o sastavu morske vode. Dobiveni rezultati su u razini vrijednosti koje se mogu naći u područjima s niskim stupnjem onečišćenja u Jadranskom moru. Slični modeli mogu se i ubuduće primijeniti u praćenju onečišćenja teških metala u morskom okolišu. KEY WORDS Adriatic seaArbacia lixula ecotoxicology electrolytes heavy metal KLJUČNE RIJEČI Jadransko more Arbacia lixula ekotoksikologija elektroliti teški metal

Interplay Between Nanoplastics and the Immune System of the Mediterranean Sea Urchin Paracentrotus lividus

“…The observed agglomeration of PS NPs in sea urchin CF can be thus ascribed to osmolarity and ion composition of the CF, which is in balance with the surrounding seawater, since sea urchins are considered osmoconformers, although some sea urchin species can sustain positive gradients for the most relevant ions (Mg 2+ , Ca 2+ , and K + ) in case of reduced salinity (Freire et al, 2011;Santos et al, 2013). Moreover, sea urchin CF contains a wide array of biomolecules, produced by the circulating coelomocytes and having key immune functions (Dheilly et al, 2013;Grassi et al, 2019), which are able to adhere on PS NP surface (protein-corona) (Freire et al, 2011;Marques-Santos et al, 2018;Fočak et al, 2019). Our previous findings showed that a highly abundant protein in sea urchin CF, the TPP, tightly bound onto PS NPs surface (hard corona) and provided a new colloidal behavior to PS NPs regardless of their surface charges.…”

“…While ion composition of sea urchin perivisceral CF can slightly differ from that of external seawater (Freire et al, 2011;Santos et al, 2013), biomolecules secreted by the circulating coelomocytes and microbes inhabiting the fluid, undergo geographical and seasonal fluctuations also as a consequence of their role in several physiological functions including immune defense (Matranga et al, 2005;Branco et al, 2014). Changes in selected ion composition (Na + , other cations and Cl − ) have been already documented in sea urchin CF as an adaptive strategy of intertidal species to counteract variations toward external environmental conditions, such as for instance environmental changes in seawater osmolarity (Freire et al, 2011;Fočak et al, 2019). Moreover, a significant increase in the concentration of specific proteins of sea urchin CF (i.e., the toposome, also known as major yolk protein and other molecules) has been reported during the reproductive cycle both in female and male specimens (Ura et al, 2017).…”