Experimental results provide evidence that trophic interactions between ciliates and Daphnia are constrained by the comparatively low food quality of ciliates. The dietary sterol content is a crucial factor in determining food quality for Daphnia. Ciliates, however, presumably do not synthesize sterols de novo. We hypothesized that ciliates are nutritionally inadequate because of their lack of ...

The bioaccumulation of estrone by Daphnia magna was determined. Direct uptake via the aqueous medium occurred within the first 16 h. A bioconcentration factor of 228 was established over all temporal periods. Ingestion via Chlorella vulgaris gave a partitioning factor of 24, which may approximate to a biomagnification factor assuming steady state conditions. These preliminary results indicate t...

Recently nanoparticles, particularly silver nanoparticles, are broadly used in industry, hence the contamination of the environment with AgNPs has caused considerable concern. In this study, the toxicity of biosynthetic nanosilver produced by two macroalgae: Sargassum boveanum and Ulva flexuosa extracts were compared with chemical nanosilver in Daphnia magna. Size and quality of nanoparticles e...

In this study, we investigated the kinetic aspects of the microcystin (MC) transfer from Planktothrix rubescens to Daphnia magna by carrying out exposure experiments in small simple mesocosms. We hypothesized that higher fractions of toxic cyanobacteria in the diet of grazers would shift the balance towards a greater than linear, i.e. non-linear accumulation of MC in D. magna. This hypothesis w...

PURPOSE To analyze the long-term effects of exposure to low-dose γ-irradiation on survival and life span in directly irradiated Daphnia magna and their offspring. MATERIALS AND METHODS One-day-old Daphnia magna were exposed to 10, 100 and 1000 mGy of acute γ-rays. The life-span of irradiated and control animals, as well as their non-exposed progeny was analyzed. RESULTS Irradiation at dose ...

It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from di...

Effects of Daphnia magna enriched with cod liver oil (CLO) as a source of highly unsaturated fatty acid (HUFA) on growth, survival, stress resistance, and fatty acid composition of the Persian sturgeon larvae were evaluated. Daphnia enriched for three different time periods (3, 6, and 9 hours) and non-enriched Daphnia were fed to the Persian sturgeon larvae (average weight 61.6±0.4mg) during 14...

Extinction is ubiquitous in natural systems and the ultimate fate of all biological populations. However, the factors that contribute to population extinction are still poorly understood, particularly genetic diversity and composition. A laboratory experiment was conducted to examine the influences of environmental variation and genotype diversity on persistence in experimental Daphnia magna po...

The assumption of the individual effective dose is the basis for the probit method used for analyzing dose or concentration-response data. According to this assumption, each individual has a uniquely innate tolerance expressed as the individual effective dose (IED) or the smallest dose that is sufficient to kill the individual. An alternative to IED, stochasticity suggests that individuals do n...