A genomic fragment containing the hemoglobin gene dmhb4 of Daphnia magna was cloned and its nucleotide sequence determined. Concerning induction under hypoxic conditions, dmhb4 was found to be expressed constitutively with similar mRNA quantities in D. magna bred in either normoxic or hypoxic medium. Southern blot analysis revealed at least six hemoglobin-like sequences in the genome of Daphnia...

Chemicals released into the environment have a potential to affect on various species and evaluation of the impacts on ecosystems including aquatic organisms is urgent issue. In order to evaluate chemical effects on various species, it is important to understand their mode of action. Recent advances in toxicogenomics, the integration of genomics into toxicology is promising for understanding mo...

Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present study, Daphnia magna populations were initiated with different levels of intraspecific competition...

The cellular architecture of the Daphnia compound eye visual system was studied by using computer-aided techniques. All the neurons in one half of the bilaterally symmetric optic ganglion (OG) were reconstructed in three dimensions from serial electron micrographs. The techniques employed were those developed by Levinthal and collaborators (Macagno, Levinthal, and Sobel, Ann. Rev. Biophys. Bioe...

widespread use of pharmaceuticals has resulted in mixture concentrations ranging from mg/l in effluent to µg/l concentrations in surface water. in a 2008 study, 13 pharmaceuticals, ranging in amounts from 0.0028 to 0.1757 µg/l, were identified in the tennessee river, usa and its tributaries. in order to address the need for risk assessment of environmentally relevant pharmaceutical mixtures, da...

Industrial wastes may produce leachates that can contaminate the aquatic ecosystem. Toxicity testing in acute and chronic levels is essential to assess environmental risks from the soluble fractions of these wastes, since only chemical analysis may not be adequate to classify the hazard of an industrial waste. In this study, ten samples of solid wastes from textile, metal-mechanic, and pulp and...