The sub-lethal effects and tissue concentration of the human pharmaceutical atenolol in rainbow trout (Oncorhynchus mykiss).

Atenolol is a highly prescribed anti-hypertensive pharmaceutical and a member of the group of β-blockers. It has been detected at concentrations ranging from ng L(-1) to low μg L(-1) in waste and surface waters. The present study aimed to assess the sub-lethal effects of atenolol on rainbow trout (Oncorhynchus mykiss) and to determine its tissue-specific bioconcentration. Juvenile rainbow trout were exposed for 21 and 42 days to three concentration levels of atenolol (1 μg L(-1) - environmentally relevant concentration, 10 μg L(-1), and 1000 μg L(-1)). The fish exposed to 1 μg L(-1) atenolol exhibited a higher lactate content in the blood plasma and a reduced haemoglobin content compared with the control. The results show that exposure to atenolol at concentrations greater than or equal to 10 μg L(-1) significantly reduces both the haematocrit value and the glucose concentration in the blood plasma. The activities of the studied antioxidant enzymes (catalase and superoxide dismutase) were not significantly affected by atenolol exposure, and only the highest tested concentration of atenolol significantly reduced the activity of glutathione reductase. The activities of selected CYP450 enzymes were not affected by atenolol exposure. The histological changes indicate that atenolol has an effect on the vascular system, as evidenced by the observed liver congestion and changes in the pericardium and myocardium. Atenolol was found to have a very low bioconcentration factor (the highest value found was 0.27). The bioconcentration levels followed the order liver>kidney>muscle. The concentration of atenolol in the blood plasma was below the limit of quantification (2.0 ng g(-1)). The bioconcentration factors and the activities of selected CYP450 enzymes suggest that atenolol is not metabolised in the liver and may be excreted unchanged.

Supramolecular Polymers in DNA Nanotechnology

Creation of biocompatible functional materials is an important task in supramolecular chemistry. In this contribution, we report on noncovalent synthesis of DNA-grafted supramolecular polymers (SPs). DNA-grafted SPs enable programmed arrangement of oligonucleotides in a regular, tightly packed one-dimensional array. Further interactions of DNA-grafted SPs with complementary DNA strands leads to the formation of networks through highly cooperative G-C blunt-end stacking interactions. The structural changes in the polymeric core enable to monitor spectroscopically the stepwise formation of networks. Such stimuli-responsive supramolecular networks may lead to the development of DNA-based smart materials.

Broad Concerns about Nanotechnology Patents: Symptoms and Diagnosis

We discuss the concerns that the patenting activity in the new nanotechnologies could blur the line between what is considered a discovery and what can be considered as an invention. We find that the nature of nanotechnology products, research, and the development agendas in science and engineering fields that include biomimetics pose a challenge to the present practice of including chemicals as eligible patent subject matter. After revisiting the historical development of patent law and noting its divergence from the developments in science and technology, we introduce the distinction between simple and complex machines as these relate to chemistry and nanotechnology. This distinction poses the question of what is the logical category of inventions that fall within patentable subject matter given that patent law was conceived to cover simple machines, not complex ones.