University of Zagreb. Faculty of Science. Department of Biology.
Abstract
Probavna žlijezda puževa ima ulogu u sintezi i izlučivanju probavnih enzima, preuzimanju i konačnoj probavi hrane, naknadnom unosu hranjivih tvari, detoksikaciji te je važno mjesto za sintezu vitelogenina i spolnih steroidnih hormona. Spojevi poput tributil kositra (TBT) koji se koriste kao protuobraštajne boje na brodovima imaju negativan utjecaj na fiziološke procese pridnenih puževa i izazivaju značajne promjene u građi probavnih žlijezda i spolnih organa. U ovom istraživanju analizirano je 147 jedinki kvrgavog volka (Hexaplex trunculus) prikupljenih sa 7 lokacija u srednjem Jadranu. Vanjskim pregledom spolnih organa zabilježena je pojava imposeksa (razvoj muških spolnih karakteristika u ženki), dok su histološke promjene u tkivu probavne žlijezde analizirane na digitalnim slikama trajnih histoloških preparata, uz upotrebu histomorfometrijskog računalnog programa. Rezultati su pokazali da volci sa svih 7 lokacija imaju histološke promjene u probavnoj žlijezdi, a one su izraženije na uzorcima s lokacija koje su pod većim utjecajem plovnog prometa, poput područja oko luke Split. Pojava imposeksa je zabilježena u 88,5% analiziranih ženki, pri čemu je ustanovljeno da 67,7% ženki ima uznapredovale stadije koji onemogućavaju reprodukciju. Ustanovljena je statistički značajna razlika u površini lumena kanalića između lokacija, te povezanost površine lumena kanalića i različitih stadija imposeksa. Na histološkim preparatima probavne žlijezde uočeno je povećanje lumena kanalića, vakuolizacija tkiva te nekroza stanica epitela kanalića, što upućuje da su organokositreni spojevi u vodama istraživanih lokacija i dalje prisutni u visokim koncentracijama.Hepatopancreas of snails has a role in the synthesis and secreting of the digestive enzymes, taking over and the final digestion of food, the additional taking of nutrients, detoxication and is an important place for the synthesis of vitellogenin and sexual steroid hormones. Compounds like tributyltin (TBT), which are used as antifouling paints for ships, have a negative effect on physiological processes of the bottom-dwelling snails and cause significant changes in the structure of the hepatopancreas and genitals. During this research, 147 banded dye-murex (Hexaplex trunculus) were collected from seven different locations in the central Adriatic Sea. By the examination of the external genitals, the occurrence of the imposex (the imposition of male sex characteristics on female snails) has been noticed, while the histological changes in the hepatopancreatic tissue were analysed by using the digital pictures of the histological slides and with the help of the histomorphometric computer program. The results have shown that the banded dye-murex from all 7 locations have histological changes in the hepatopancreas and these changes are more noticeable on the snails found on the locations where sea traffic is heavier, like the areas near Split harbour. The occurrence of the imposex has been noticed in 88.5 % of the analysed female banded dye-murex and in 67.7% of these females we detected advanced stages of imposex, which prevent reproduction. There is statistically significant difference in the surface of the lumen among locations, and between surface of the lumen and different stages of imposex. On the histological slides of the hepatopancreas, the enlargement/extension of the lumen, the tissue vacuolization and the necrosis of the channel epithelial cells have been noticed. This shows that the concentration of the TBT compounds in the waters of the investigated locations is still high
