No abstract

SummaryPrimordial germ cells are the precursors of gametes in sexually reproducing organisms. The migration and homing process of primordial germ cells are prone to environmental effects and the endocrine system hormones. One of the environmental pollutants which humans are exposed to is bisfenol A (BPA). BPA which is an endocrine disrupter generally used for making plastics harder. In this study we investigated the effects of low doses of BPA (4 mg/L and 8 mg/L) on primordial germ cells at the zebrafish embryos and larvae. Whole mount in situ hybridization for germ cell marker gene vasa showed that upon exposure to BPA, the primordial germ cell number increased and these cells ectopically localized outside the normal germ cell niche in zebrafish. Migration of primordial germ cells into ectopic locations and morphological changes in these cells were also proved by histological studies. Additionally, results of acridine orange staining to detect apoptotic cells showed that low doses of BPA did not increase apoptosis. Results of the present study showed that low doses of BPA exposure increased the number of primordial germ cells and induced ectopic primordial germ cell localization in the zebrafish embryos. Keywords: Zebrafish, Primordial germ cell, Bisphenol A Düşük Dozlardaki Bisfenol A'nın Zebra Balığı (Danio rerio) Embriyo ve Larvalarında Primordiyal Germ Hücreleri Üzerine Etkisi ÖzetPrimordiyal germ hücreleri, eşeyli üreyen canlılarda gametlerin öncül hücreleridir. Endokrin sistem hormonları ve çevresel etkenler, primordiyal germ hücrelerinin göçünü etkilemektedir. İnsanların maruz kaldığı çevresel kirleticilerden biri de bisfenol A (BPA)'dır. Endokrin sistemde hasar oluşturan biri olan BPA, genellikle plastik sertleştirme işleminde kullanılmaktadır. Bu çalışmada zebra balığı embriyo ve larvalarında düşük dozlardaki (4 mg/L and 8 mg/L) BPA'nın etkileri incelenmiştir. Bir germ hücresi belirteci gen olan vasa ile yapılan whole mount in situ hibridizasyon deneyleri sonucunda BPA'nın primordiyal germ hücre sayısında artışa sebep olduğu ve bu hücrelerin göç yolu dışındaki (ektopik) bölgelerde bulunduğu tespit edilmiştir. Primordiyal germ hücrelerinin ektopik bölgelere göçü ve bu hücrelerdeki morfolojik değişiklikler histolojik çalışmalarla da doğrulanmıştır. Buna ek olarak, düşük dozlarıyla yapılan boyamalarda apoptozisin tespitinde kullanılan akridin turuncusu boyaması sonucunda BPA'nın apoptozisi artırmadığı saptanmıştır. Bu çalışma sonuçları, düşük dozlardaki BPA'nın primordiyal germ hücre sayısını artırdığını ve bu hücrelerin ektopik bölgelere göç etmesine yol açtığını ortaya koymaktadır.

Primordial germ cells (PGCs

Aquatic organisms are exposed to significant amounts of heavy metals and pesticides due to many anthropogenic activities, particularly industrial and agricultural. Heavy metal and pesticide accumulation may cause an increase in Reactive Oxygen Species (ROS) leading to oxidative stress in fish. These environmental toxicants can promote oxidative damage by directly increasing the cellular concentration of ROS and by reducing the cellular antioxidant capacity. This paper reviews the studies on effects of heavy metals and pesticides exposure on the oxidative stress biomarkers and antioxidant defenses of fish.

The use of detergents has become widespread and is growing. The increase in population and use of detergent threatens the life of organisms in the ecosystem. In this study, the histological effects of linear alkyl benzene sulphonic acid on primordial germ cell (PGC) migration and gonad formation in zebrafish were investigated after application of 0.25 0.5 and 1 mg/L of linear alkyl benzene sulphonic acid to embryos. Samples of embryos and larvae were collected for 60 days and the effects of linear alkyl benzene sulphonic acid on PGC migration and gonad development were examined by histological procedures. The localization and migration pathway of PGCs and structures of the gonads were inspected by Periodic Acid Schiff (PAS), alkaline phosphatase, toluidine blue and Best?s carmine staining. Primordial germ cells were observed in ectopic regions and delayed gonadal development and histopathological changes in gonad structures were observed. We concluded that linear alkyl benzene sulfonic acid exposure has a negative effect on the reproduction system of zebrafish.