Browsing by Author "Ünal, G."

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Differentiation of Brain Neurosecrotory Cells Depending on Ecdysteroid Content of Haemolymph During 5 Th. Instar Larval Stage of Silkworm, Bombyx Mori
(1999) Parlak, O.; Ünal, G.
In this study, the differentiation in the lateral neurosecretion cells of pars intercerebralis of brain, depending on the different ecdysteroid contents which was determined in the hemolymph of silkworm by radioimmunoassay has been studied using light microscopy. The brains of silkworms in the time of low and high hemolymph ecdysteroid content were fixed in Bouin solution, and the cross sections were stained with PAF after dehidratation. Results shown that the density of fine secretion granulles increased in the cytoplasm of neurosecration cells just before the increase of ecdysteroid content in hemolymph. It was also observed that the ecdysteroid content in hemolynph increased in the following day of excretion.
A Histological Examination of the Sublethal Effects of Methyl Parathion on the Liver, Gills and Gonads of Alburnus Tarichi (Güldenstädt, 1814)
(Hashemite University, 2023) Kankaya, E.; Ünal, G.
Pesticides are chemicals used to control a wide variety of animals and plants. Methyl parathion (MP) is an organic phosphorus insecticide used in agriculture against animal organisms that damage the crop. Pesticides can reach water resources in different ways. May affect non-target organisms such as fish to varying degrees. Since fish is a valuable nutrient in human nutrition, its sustainability is very important. For this reason, sublethal effects of MP on Alburnus tarichi, which is economically important for the Lake Van basin, were studied. This study was carried out to determine the pathological effects of MP on the gonad, gill and liver tissues of Alburnus tarichi. Fish weighing 3‒7 g were used in the study. The semi-static test method was applied. Fish were exposed to 4.28 mg L-1 MP. The bioassay was carried out at 17.9 °C for 30 days. At the end of the test, gonad, gill and liver tissues were removed from the dissected fish for pathological evaluations. In the examinations made, cells with eosinophilic and fat accumulation in the liver, local necrosis and enlarged vessels, and yellow colored structures were determined. Thickened primary lamella, folded secondary lamella and epithelial layer separations were observed in the gills. No pathology was found in ovarian cells. Degeneration in the germ cells in the mitotic phase, interstitial tissue containing eosinophilic cell groups, enlarged follicle lumen and bleeding were observed in the testes that were not in the mitotic phase. As a result, MP is a chronic toxic substance according to histological criteria for Alburnus tarichi. MP should be used in agriculture in a controlled and careful way. © (2023). All Rights Reserved.
Histological Investigation of Gonad Development of Chalcalburnus Tarichi (P., 1811)
(1999) Ünal, G.; Çetinkaya, O.; Elp, M.
In this study, gonad development of Chalcalburnus tarichi, an anadromus, endemic fish species of the Lake Van and its inlets was histologically investigated. During oogenesis, six different development phases were histologically identified: chromatin-nucleolus, perinuclear, cortical alveolar, vitellogenic, ripening and ovulation phases. The diameters of oocytes were determined between 31 to 957 μm until the ovulation phase. According to the investigated sepcimens, vitellogenic phase started onward October and first ovulation was taken place in May-June 36 months and older females. It was found that some unspawned ova remained and formed atretic follicles in ovary after ovulation. Three different development phases were observed during spermatogenesis in testes: as unripened, ripening and ripened. Sperms started to form onward December and were released in May-June by 36 months and older males.
Histological Study of the Organogenesis of the Digestive System and Swim Bladder of the Chalcalburnus Tarichi Pallas, 1811 (Cyprinidae)
(2001) Ünal, G.; Çetinkaya, O.; Kankaya, E.; Elp, M.
The histological development of the digestive system and swim bladder of Chalcalburnus tarichi larvae and their histology in adults were studied under light microscopy. After hatching, the digestive tract is a simple undifferentiated tube. Exogenous feeding started on the 6th day. The yolk sac was absorbed completely on the 9th day. The goblet cells appeared first in the bucco-pharyngeal cavity and oesophagus on the 4th day, in the anterior on the 9th day and in the posterior intestine on the 5th day. The digestive tract was differentiated as the buccal cavity, pharynx, oesophagus post-eosophageal swelling and intestine on the 5th day. At the same time taste buds and pharyngeal teeth also started to form. In the oesophagus, the circular muscle was observed on the 9th day and the longitudinal muscle in one-year-old fish. In the intestine, the circular muscle was observed on the 35th day and the longitudinal muscle in two-year-old individuals. The wall of the digestive tract is composed of epithelial, submucosa, muscle and serosa layers. The liver lobules formed on the 3rd day and the cells began to reserve glycogen on the 10th day. The pancreatic acina formed on the 5th day and the tubular in one-year-old fish. The liver and pancreas ducts opened into the anterior intestine before the exogenous feeding started. The swim bladder was observed as one lobuled on the 4.5th day and two lobuled on the 35th day.
Histology of Corpuscles of Stannius in Lake Van Fish (Alburnus Tarichi Güldenstädt, 1814) (Cyprinidae)
(Blackwell Publishing Ltd, 2021) Kaptaner, B.; Ünal, G.; Doğan, E.; Aykut, H.
In the present study, the location, histology and number of corpuscles of Stannius (Sc), which are endocrine glands associated with the kidneys of teleost fish, were investigated for the first time in Lake Van fish (Alburnus tarichi), an anadromous and endemic inhabiting Turkey's Lake Van Basin. The Sc, which were ovoid or spheroid and white or cream in colour, were found to vary in number between three and five among the examined fish. The glands were located in the caudal part of the kidney, and either partially or completely embedded, and found to be present on both the ventral and dorsal surface of either side of the caudal part of the kidney. The Sc were surrounded by a connective tissue capsule that penetrated and divided the gland into incomplete lobules. Two types of cells were determined in the parenchyma of the gland. Type-I cells were predominant throughout the parenchyma and larger than the second (type-II). In the type-I cells, the cytoplasm was observed as weakly or moderately eosinophilic with haematoxylin and eosin staining and weakly or moderately acidophilic with Mallory's triple staining. In the type-I cells, the cytoplasm exhibited weak to moderate periodic acid-Schiff staining and slight or uniform staining with aldehyde fuchsin. The type-II cells were round, had a darkly stained spherical nucleus and were dispersed among the type-I cells. They displayed no cytoplasmic staining with the abovementioned stains. © 2020 Wiley-VCH GmbH
A Study of the Some Growth Parameters of Barbel (Barbus Plebejus Ercisianus, Karaman, 1971) Living in the Koçköprü Dam Lake Basin-Turkey
(2006) Elp, M.; Çetinkaya, O.; Kankaya, E.; Şen, F.; Ünal, G.
This study was carried out to determine some growth parameters of barbel populations living in the Koçköprü Dam Lake and its inlets between April 2000 and October 2001. The barbel species are shown a widespread distribution in Turkey. The species is native in study area, has economic value and is fished local fishermen. A total of 324 individuals were sampled. The maximum age of individuals was determined as VII, fork length was 33.8 cm and weight was 428.0 g. Females were found larger than males in size. Condition factor values were determined as 1.210±0.009 for males, 1.266±0.017 for females and 1.293±0.030 for juveniles. In overall, condition factor of females was higher than males. Length-weight relationship was determined for whole samples as logW = -1.841+2.934 logL. © 2006 Asian Network for Scientific Information.