Sedat V. Yerli

Histopathological changes in the livers and kidneys of fish in Sariyar Reservoir, Turkey.

In this study, a total of 180 fish specimens (wels: Silurus glanis-60; common carp: Cyprinus carpio-60; bleak: Alburnus escherichii-60) of ages between one and two were caught at three different stations in Sariyar Reservoir. The histological changes in the livers and kidneys of three different species of fish were detected microscopically and evaluated with quantitative analyses. Also, organochlorine pesticide residues (OCP) have also been determined in the water and sediment samples and in the adipose tissues of fish caught in these stations. Results show that the reservoir was polluted by different kinds of OCP compounds and these chemicals have accumulated in the fish tissues. As a result of these analyses, histopathological changes were observed in the livers and kidneys of fish specimens, such as mononuclear cell infiltration, congestion and nuclear picnosis. Also intra-cytoplasmic cholestasis in their livers and tubular degenerations in the kidneys were observed. The incidences of the histopathological changes in wels and carps were found to be higher than bleak. Furthermore, histopathological changes in fish samples caught from Usakbuku were much more than the samples caught from other stations (Sariyar and Nallihan Bird Paradise Stations). In this study the possible reasons of histopathological changes were evaluated with respect to different fish species and localities and also the findings were evaluated in relation to OCP contamination.

Predicting dominant phytoplankton quantities in a reservoir by using neural networks

The Levenberg–Marquardt algorithm was used to train artificial neural networks to predict the abundance of Cyclotella ocellata Pant. and Cyclotella kützingiana Thwaites using time, depth, temperature, pH, dissolved oxygen, and electrical conductivity as input parameters for the oligo-mesotrophic Kuzgun Dam Reservoir, Turkey. The data were collected in monthly intervals during two ice-free seasons: between April 2000–November 2000 and April 2001–November 2001. To reduce over-fitting of the neural network based models, we employed single hidden layer networks with early stopping of training. Correlation coefficients of neural network predictions with measurements of abundance of Cyclotella ocellata Pant. and Cyclotella kützingiana Thwaites were 0.88 and 0. 86, respectively.

The effects of zeta cypermethrin on the gills of common guppy Lebistes reticulatus.

Effects of lethal and sublethal concentrations 15, 20, 26 and 35 μg/l of zeta cypermethrin on the gills of common guppies (L. reticulatus) were examined by light microscopy during 96 h exposure. The most common changes at all doses of zeta cypermethrin are the lifting of epithelial layer from gill lamellae and some necrosis. Besides the exudation, hyperplasia and the shortening of secondary lamellae were other histopathological effects. The 96 h LC(50) value for zeta cypermethrin to the L. reticulatus was determined 21.35 μg/l.

Systematic evaluation of the genus Alburnus (Cyprinidae) with description of a new species

The genus Alburnus, a member of the Cyprinidae family, includes 43 species that are widely distributed in Europe and the northern part of Western Asia. To date, inter-specific relationships within the genus have not been assessed in detail. The main objective of this research was to assess phylogenetic relationships of the genus and solve taxonomic uncertainties. For this purpose, the mitochondrial gene cytochrome c oxidase subunit I (COI) was selected and analyzed by Bayesian and maximum-likelihood approaches. Inter- and intra-specific genetic distances of the putative species were calculated. In addition, body shape was quantified by landmark-based geometric morphometrics on the available material from Turkey in order to determine whether the emerging patterns of shape are congruent with the COI phylogeny. Our data suggest multiple synonymies within the genus and the addition of a new species, Alburnus kurui sp. n., from the Dalaman River. We conclude that by including this new species and considering the synonymies, the genus Alburnus now comprises 36 species.

Development and characterization of new polymorphic microsatellite loci for Trionyx triunguis(Testudines: Trionychidae) in the Mediterranean Basin

The Mediterranean subpopulation of T. triunguishas been listed by IUCN as critically endangered (European Reptile and Amphibian Specialist Group 1996, category CR C2A). There are very few studies for determination of distribution and population genetics of this species in the world. A total of 13 polymorphic microsatellite loci were isolated from 42 samples of T. triunguisby using biotinylated (GT) 10, (CT) 10, (GATA) 5-enriched library. The range of observed heterozygosities was 0.000-0.833 with a mean of 0.274, and the range of expected heterozygosities was 0.081-0.607 with a mean of 0.374. It was found that four loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni correction analysis. There was no evidence for large allele dropout. Null alleles may be present at ttmed-6, ttmed-8, and ttmed-9 loci, as suggested by the general excess of homozygote for most allele size classes. Designed microsatellite loci could provide a powerful tool for the population structure and conservation genetics studies of the Nile soft-shelled turtle and for captive breeding programs or to detect species illegal trade.