Ferah Sayim

Toxic effects of anatoxin-a on testes and sperm counts of male mice.

Anatoxin-a, a potent neurotoxin, is one of a number of toxins produced by cyanobacteria especially some strains of Anabaena. Toxic cyanobacteria are found worldwide in inland and coastal water environments. The present study was performed to evaluate the toxicity of anatoxin-a on testes and sperm counts of male mice. The animals of the treatment groups were administered with 50, 100 and 150microg/kg/day anatoxin-a for seven consecutive days by intraperitoneal (i.p.) route. Although there were no significant changes in body weight gain, and absolute and relative testes weights, absolute and relative weights of cauda epididymis reduced significantly in the 100 and 150microg/kg groups when compared with control group. The number of sperm count in cauda epididymis was reduced dose dependently in all treatment groups compared with control animals. Anatoxin-a caused dose-dependent histopathological changes in the testes of mice such as degenerations in seminiferous tubules, intercellular disassociation of spermatogenetic cell lines, sloughing of germ cells into tubular lumen, vacuolisation in Sertoli cells and loss of germ cells. The epithelial thickness of seminiferous tubules decreased significantly in all treatment groups in a dose-dependent manner.

Embryonic development of the tree frog, Hyla arborea

A staged series with time data and original photographs of the embryonic development of the tree frog, Hyla arborea are presented, following Gosner’s generalized table. To contribute to species specific embryological studies of anurans, the external features of development of this species were described. Duration of embryonic development, from fertilization to 25th stage, is about 9 days at 20 ± 1 °C. Cleavage is holoblastic and unequal. Unlike the typical anuran development, neurular rotation was not observed in stage 15 or in any other stages. Other developmental stages resulted in a normal-looking. Embryos of H. arborea hatched at stage 20 or 21, which varied individually. Hatching occurred in the 4th or 5th day after fertilization. The mean total length of hatchlings was calculated as 6.38 mm. The mean size of ovum was estimated 1.4 mm in diameter.

Reproductive ecology and body size-fecundity relationships of the Green Toad,Pseudepidalea viridis(Laurenti, 1768), in the Kocaçay Stream, İzmir, Turkey: (Amphibia: Anura)

Abstract We studied the breeding biology of the Green Toad, Pseudepidalea viridis (Laurenti, 1768), in the 2007–2008 breeding seasons at Kocaçay Stream. The breeding period began in early February and lasted approximately two months. The median of the breeding seasons was calculated as 5tMarch for the entire study period 2007–2008. The average clutch size was 14,594 eggs and this value was higher than in other conspecific populations from Denmark, Israel and Italy. Clutch size and clutch mass were significantly correlated with female body size, but single egg mass and egg diameter were not. A negative significant correlation was seen between clutch size and egg diameter.

Some water chemistry parameters of breeding habitats of the Caucasian salamander, Mertensiella caucasica in the Western Lesser Caucasus

Selection of breeding habitat plays a fundamental role in the reproductive success of urodeles and anurans. We studied the influence of water chemistry variables on the selection of a specific water resource as breeding habitat in Mertensiella caucasica. To determine the influence of water chemistry parameters on their habitat selection, we surveyed a total of 45 small river, streams and brooks in the Western Lesser Caucasus (northeastern Turkey and southwestern Georgia). The water samples taken from these localities were analyzed for 14 chemical variables and the results submitted to multiple logistic regression analysis in order to evaluate the influence of these parameters on the presence or absence of the species in the localities. Of these parameters, chloride concentration influenced the breeding habitat selection of Mertensiella caucasica significantly.