Adaptation of Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) on genotoxic stress

Antropogeno djelovanje na okoliš između ostalog uključuje i onečišćenje, odnosno ispuštanje raznih anorganskih i organskih tvari u okoliš. Utjecaj onečišćenja na organizme može se najranije zamijetiti na molekularnoj i staničnoj razini. Mjerenja oštećenja DNA su od posebne važnosti za određivanje stresa uzrokovanog onečišćenjem i procjenu okolišnog rizika. U svrhu analize intenziteta genotoksičnog djelovanja detektirana su oštećenja DNA u hemocitima vrste Mytilus galloprovincialis iz nativnih i kavezno izlaganih populacija na postajama Pula - luka, Ičići, Limski kanal, Rijeka - luka, brodogradilište u Sjevernom Jadranu, Split - luka, Marina, Trogir - marina, Adriavinil, Zadar Borik, Zadar – marina, Gruž - luka, Mali Ston, Ston, NP Mljet u jesen 2013. i proljeće 2014. godine, te izlaganjem dagnji s postaja Gruž i Marina bakru u mesokozmos eksperimentu. Za ovo istraživanje korištena je metoda komet-testa. Utjecaj onečišćenja na okoliš procijenjen je iz literaturnih podataka te kemijskih analiza metala u tkivu dagnji. Uzorkovane populacije pokazale su nizak do umjeren stupanj utjecaja onečišćenja. Najveće odstupanje pokazale su dagnje s postaja Gruž i Pula, za koje je izmjeren i značajno najviši genotoksični utjecaj. Analiza oštećenja DNA kavezno izlaganih jedinki pokazala je blago snižen integritet DNA u odnosu na kontrolnu postaju Marina, no jedino su jedinke s postaje Gruž imale statistički značajnu razliku. Sezonske fluktuacije na istraživanim postajama čine interpretaciju kemijskog onečišćenja vrlo kompleksnom, što se može zaključiti iz dobivenih podataka. Rezultati mezokozmos eksperimenta pokazali su veće oštećenje DNA kod dagnji s onečićene postaje. Ovo istraživanje naglašava važnost razumijevanja ekoloških faktora (salinitet, temperatura, pH) u interpretaciji dobivenih podataka. Nadalje, adaptacija populacija na lokalno onečišćenje može igrati veliku ulogu u dobivenim rezultatima.Anthropogenic effect on the environment includes pollution, i.e. emission of various inorganic and organic substances into the ecosystem. The earliest effect of pollution on the organisms can be detected on the molecular and cell levels. Studies of genotoxicity biomarkers such as DNA damage are of great importance for understanding pollution related stress and environmental risk assessment. The genotoxic effect was studied on the Mytilus galloprovincialis haemocytes using comet assay. Native populations were sampled in fall 2013. and in spring 2013 on the locations: Pula - harbour, Ičići, Lim Bay, Rijeka - harbour, shipyard in the northern Adriatic, Split - harbour, Marina, Trogir - marina, Adriavinil, Zadar Borik, Zadar – marina, Gruž - harbour, Mali Ston, Ston, NP Mljet. In addition, population Marina was cage exposed on six sites in transplant experiment, and populations Gruž and Marina were exposed to copper in mesocosm experiment. The pollution effect on the mussel populations was estimated by literature data and chemical analysis of heavy metals in the mussel tissue. These results indicated low to moderate level of pollution. DNA damage analysis in native populations did not show significant difference between all of the control and polluted stations. The biggest aberration was seen in the mussels from the locations Gruž and Pula, which had the highest genotoxic effect. DNA damage analysis in transplanted populations showed slightly decreased DNA integrity in respect to the control station Marina, and statistical significance was reached only for mussels exposed at site Gruž. Mesocosm experiment showed higher DNA damage in mussels from polluted site. Seasonal fluctuations of environmental conditions at the study sites make interpretation of pollution effect complex, as seen especially in the variability of the results on DNA damage. These investigations further stress the importance of understanding the effects of natural factors (salinity, temperature, pH) for the interpretation of the data obtained. In addition, adaptation and acclimatisation of populations to local pollution may play a role in some of the response patterns observed