Browsing by Author "Yesilbas, Ayse"

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Investigation of Hematopoietic Precursor Cells in the Peripheral Blood Tissue of Van Fish (Alburnus Tarichi, Güldenstädt, 1814)
(Pleiades Publishing Inc, 2026) Yesilbas, Ayse; Oguz, Ahmet Regaib
The Van fish (Alburnus tarichi, G & uuml;ldenst & auml;dt, 1814) is an anadromous teleost species that has adapted to the saline and alkaline waters of Lake Van. Between the months of April and July, the fish migrate for breeding to the freshwater streams that flow into Lake Van. The aquatic habitats affect many physiological parameters of the fish, including blood values such as the morphological structure and count of blood cells. Exogenous factors like temperature and oxygen levels of the aquatic environment trigger the release of hormones involved in hematopoiesis. In this study, hematopoietic precursor cells in the peripheral blood tissue of fish sampled from the alkaline and saline waters of Lake Van and freshwater streams during the breeding migration were histologically examined. According to the findings, a difference was observed in the number of precursor cells between the lake and stream locations (P < 0.05). Fish sampled from the stream contained a higher number of precursor cells compared to those from the lake. The examination of peripheral blood tissue revealed that erythroblasts and myelocytes were present in greater numbers. It was noted that neutrophil myelocytes were more numerous than monocyte and lymphocyte precursor cells. Basophil precursor cells were rarely observed in the peripheral blood. However, platelet precursor cells were not found in the peripheral blood tissue. As a result, it was noted that exogenous factors in the aquatic environment trigger hematopoiesis in the peripheral blood tissue of the Van fish and increase the number of precursor cells.
Investigation of Some Hormones Affecting Osmoregulation of Lake Van Fish (Alburnus Tarichi) During Reproductive Migration
(Wiley, 2022) Yesilbas, Ayse; Oguz, Ahmet Regaib
Lake Van is one of the largest soda lakes in the world. The extreme characteristics of the lake greatly limit the animals living there. Lake Van fish (Alburnus tarichi Guldenstadt, 1814) is the only vertebrate species that has adapted to this environment. Lake Van fish migrate to freshwater every year to breed, after which, they return to the lake environment. The fish are exposed to different aquatic environments during migration. The endocrine mechanisms involved in the physiological changes during this migration are not studied in this species, yet. In this study, water and serum sodium, potassium and chloride levels in the lake, downstream and upstream to which Lake Van fish are exposed during reproductive migration were determined. Circulating cortisol, free triiodothyronine, free thyroxine, insulin-like growth factor-I, growth hormone and prolactin levels were also investigated. It was observed that the water ion levels decreased in the freshwater localities when compared to the lake localities, and the serum Na+ and Cl- levels decreased in upstream1 and upstream2, K+ levels stayed at a certain level in all localities. It was determined that the hormone levels differed in the upper regions of the river (upstream1 and upstream2), where spawning was completed, from the lake environment, where reproductive migration began. Results indicate that the studied hormones had direct and indirect effects on osmoregulation in the Lake Van fish with the physiological tendency to keep osmotic homeostasis, as occurs in other teleost species.
Investigation of the Therapeutic Effect of Melatonin on Deltamethrin Applied Mouse Primary Hepatocyte Culture
(Taylor & Francis Ltd, 2025) Kaval Oguz, Elif; Oguz, Ahmet Regaib; Ozok, Necati; Alkan, Zehra; Ergoz Azizoglu, Burcu; Orgi, Elif; Yesilbas, Ayse
ObjectiveIn recent years, it has been known that the melatonin hormone, secreted from the pineal gland, possesses significant antioxidant activity. This study explores the therapeutic effect of melatonin on the deleterious effects of deltamethrin, a pyrethroid pesticide extensively used worldwide, including in T & uuml;rkiye, on mouse liver cells.MethodsHepatocytes from Balb/C mice were isolated using a two-stage perfusion method, resulting in over 85% live hepatocytes. The isolated cells were cultured with different doses of deltamethrin (1 and 10 mu M) and melatonin (100 mu M) for 24 and 48 hours. At the conclusion of the culture period, hepatocytes were extracted at the 24th and 48th hours, and Malondialdehyde (MDA), Total Antioxidant Capacity (TAC), Total Oxidation Status (TOS), and DNA damages (8-hydroxy-2'-deoxyguanosine (8-OHdG)) were examined.ResultsWhile an increase in MDA, TOS, and DNA damage was observed in the deltamethrin-administered groups of hepatocytes, a decrease in TAC level was noted. It was determined that the applied deltamethrin had no effect on cell viability throughout the application period.ConclusionFurthermore, it was observed that melatonin, when administered concurrently with deltamethrin, reduced the toxic effect of deltamethrin. This study suggests that melatonin has a protective effect against deltamethrin-induced damage in mouse hepatocyte cells.