Anatomical and histological investigation of the pineal gland in the lake van fish (Alburnus tarichi (Güldenstädt, 1814)).

The pineal gland and melatonin secreted from the gland regulate the biological clock and adaptation to seasonal changes, glucose balance, nutrition and locomotor activities. In this study, the pineal gland of the Lake Van fish was examined anatomically and histologically. The melatonin level secreted from the pineal gland was determined in fish plasma sampled from both lakes and streams during reproduction migration. The pineal gland in the Lake Van fish, as in other teleost fish, is located in the head, under the translucent pineal window, which does not contain many pigment cells. The gland consists of pineal vesicle and pineal stalk parts on the dorsal sac in the Lake Van fish. It was determined that the pineal gland showed good vascularity. The presence of pinealocytes and different types of cells in the pineal organ was determined histologically. Pinealocytes were intensely localized in the lumen of the pineal vesicle. The plasma melatonin level increased in fish passing from lake to stream for reproductive migration.

Effects of chlorpyrifos on primary gill cell culture of Lake Van fish (Alburnus tarichi Güldenstaadt 1814).

Lake Van fish (Alburnus tarichi Guldenstadt 1814) is the only fish that can adapt to the extreme conditions (pH 9.8 salinity 0.2% and alkalinity 151.2 meq/L) of Lake Van. In this study, it was aimed to determine the cytotoxic and genotoxic effects of chlorpyrifos (CPF) on Lake Van fish primary gill cell culture. Gill epithelium from Lake Van fish was isolated enzymatically and grown in primary culture on Leibovitz's L-15 medium. After different doses (0.01, 0.1, 1, and 10 µM) of CPF were applied to the gill cells, the total oxidant status (TOS), total antioxidant status (TAS), malondialdehyde (MDA), and DNA damage levels (8-hydroxyguanine (8-OHdG)) were examined at the end of 24 and 48 h. It was determined that the TOS, MDA, and 8-OHdG levels increased in the cells exposed to high doses (1 and 10 µM) of CPF and the TAS was decreased (P < 0.05). It was revealed from this study that CPF administered at a dose higher than 1 µM can cause oxidative stress and DNA damage in the primary gill cell culture of Lake Van fish. In addition, the findings showed that Lake Van fish primary gill cell culture was useful in determining the effects of toxic substances likely to be the contaminants of a lake.

Histopathology and immunohistochemistry of gills of Van fish (Alburnus tarichi Güldenstädt, 1814) infected with myxosporean parasites.

The Van fish are a cyprinid species endemic to Turkey's largest soda lake, Lake Van, and have great economic value because they are a food source. Once a year, the fish take part in reproductive migration to the fresh waters flowing into the lake. The fish migrate from an extreme environment with high salinity (2.2%) and high pH (9.8). These fish are unable to reproduce in this alkaline environment and must migrate to fresh water during their breeding season. The aim of the present study is to report the presence of the myxosporean parasites on the gills and the pathological changes. Changes in gill histopathology, mucocytes, mitochondria-rich cells, expression of Heat Shock Protein 70 (Hsp70), and ATPase (NKA) were observed in the gill tissue. As a result of the histopathological changes in gills, infected fish had abundant plasmodia with different sizes. Plasmodia were found on gill filaments inside white ovoid-shaped structures. It was observed that plasmodia were contained on the primary filament which changed the histological structure of the gill tissue to a large extent. It was determined that the density and size of mucocytes in the infected areas of the gill tissue increased, whereas the number of mitochondria-rich cells decreased. Hsp70, an indicator of stress, was not different between normal and infected fish.

Antioxidant responses and DNA damage in primary hepatocytes of Van fish (Alburnus tarichi, Güldenstadt 1814) exposed to nonylphenol or octylphenol.

Alkylphenols, a nonionic surface-active agent group, such as nonylphenol (NP) and octylphenol (OP) are important endocrine-disrupting chemicals (EDC). In this study, the dose- and time-dependent effects of NP and OP were investigated in the primary hepatocyte culture of Van Fish. In this study, samples were taken at different times and biochemical parameters were studied separately. The effects of the chemicals used on SOD, CAT, GSH-Px, MDA, and 8-OHdG were investigated in hepatocyte culture. The antioxidants SOD and CAT were observed to increase in all groups in the primary hepatocyte cultures at the 24th hour after NP and OP administration, whereas the GSH-Px level was observed to increase with OP at the 24th hour and with NP at the 48th hour. The MDA level was observed to reach its highest value for both chemicals in the 24th hour, and the 8-OHdG level was observed to increase toward the end of the follow-up time, compared to the control group (p < 0.05). In conclusion, different doses of NP and OP were found to induce an increase in the levels of antioxidants and the MDA level in Van Fish primary hepatocyte culture. DNA damage, on the other hand, may be considered to appear after longer-term exposure to NP and OP.