Browsing by Author "Cekic, Zehra Alkan"

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Histological Investigation of Pseudobranch During Reproductive Migration of Van Fish (Alburnus Tarichi, Güldenstädt, 1814)
(Springer, 2025) Cekic, Zehra Alkan
Lake Van is the largest lake in Turkey and one of the few soda lakes in the world. The Lake Van fish (Alburnus tarichi), an endemic carp species, has fully adapted to the soda water in this lake. As an anadromous fish, it migrates from the lake to Freshwater (FW) every year between April-July. During migration, the fish activate osmoregulatory mechanisms to maintain water and salt balance. This study examined the pseudobranch tissues of Lake Van fish from both Lake Van and Karasu Stream. Morphological analysis showed that the pseudobranch, located on both opercular valves, was covered with transparent connective tissue. Histologically, the tissue contained different cell types, including pavement, pillar cells, and erythrocytes. Higher mucous cell density were found in the stream environment, while immunohistochemical (IHC) analysis showed more Na+/K+-ATPase-positive cells in the stream fish. These results suggest that the pseudobranch plays a key role in osmoregulation, helping the fish adapt during migration.
Immunohistochemical Examination of Hsp70, Pcna, 8-Ohdg, Inos and Apoptosis in the Gills of Lake Van Fish (Alburnus Tarichi (Güldenstädt, 1814)) After Esfenvalerate Exposure
(Taylor & Francis Ltd, 2025) Cekic, Zehra Alkan; Orgi, Elif; Oguz, Ahmet Regaib; Otun, Yagmur
Lake Van fish is an endemic carp species adapted to the soda waters of Lake Van. As a result of agricultural and livestock activities around the lake, many environmental pollutants are dumped into the lake as waste. Esfenvalerate is a pyrethroid pesticide used extensively in agricultural areas in the region. In this study, Lake Van fish were exposed to a sublethal dose of esfenvalerate (0.158 mu g/L) for 24, 48, 72, and 96 hours, and their gill tissues were examined immunohistochemically. Histopathological analysis determined that hyperplasia and necrosis occurred in the gill tissue as a result of exposure. Additionally, the heat shock protein 70 (HSP70), proliferating cell nuclear antigen (PCNA), 8-hydroxy-2' -deoxyguanosine (8-OHdG), and nitric oxide synthase (iNOS) positive cells and the number of apoptotic cells were determined by immunohistochemistry in gills of Lake Van fish exposed to esfenvalerate. The density of cells containing HSP70 and PCNA increased at 24 and 48 hours of exposure to esfenvalerate. 8-OHdG occurred in gill tissue as a result of esfenvalerate exposure, and the number of damaged cells increased over time. The number of apoptotic cells and containing the inducible isoform of iNOS increased in the gill tissue as a result of esfevalerate exposure. Overall, it was determined that esfenvalerate had a toxic effect on Lake Van fish gills.