Growth-induced mass flows in fungal networks

Cord-forming fungi form extensive networks that continuously adapt to maintain an efficient transport system. As osmotically driven water uptake is often distal from the tips, and aqueous fluids are incompressible, we propose that growth induces mass flows across the mycelium, whether or not there are intrahyphal concentration gradients. We imaged the temporal evolution of networks formed by Phanerochaete velutina, and at each stage calculated the unique set of currents that account for the observed changes in cord volume, while minimizing the work required to overcome viscous drag. Predicted speeds were in reasonable agreement with experimental data, and the pressure gradients needed to produce these flows are small. Furthermore, cords that were predicted to carry fast-moving or large currents were significantly more likely to increase in size than cords with slow-moving or small currents. The incompressibility of the fluids within fungi means there is a rapid global response to local fluid movements. Hence velocity of fluid flow is a local signal that conveys quasi-global information about the role of a cord within the mycelium. We suggest that fluid incompressibility and the coupling of growth and mass flow are critical physical features that enable the development of efficient, adaptive biological transport networks.     

Determination of the inorganic degradation products sulfate and sulfamate in the antiepileptic drug topiramate by capillary electrophoresis

A capillary electrophoresis (CE) method has been developed as an alternative method for the determination of the inorganic degradation products sulfate and sulfamate in topiramate drug product and drug substance, currently performed by ion chromatography. The anions are separated in a background electrolyte containing potassium chromate and boric acid, followed by indirect UV detection. By adding tetradecyltrimethylammonium bromide to the electrolyte, analysis is performed under co-electroosmotic flow conditions. Variations in injection volumes and migration times are compensated for by use of an internal standard. The validation of the method, which was performed according to ICH guidelines (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use) [1], comprises specificity, accuracy, linearity, precision, sensitivity and robustness. In addition, the results of an actual tablet sample analysis obtained by this CE method are statistically shown to be in close agreement with those obtained by an ion chromatographic method.     

Atx1-like chaperones and their cognate P-type ATPases: copper-binding and transfer

Copper is an essential yet toxic metal ion. To satisfy cellular requirements, while, at the same time, minimizing toxicity, complex systems of copper trafficking have evolved in all cell types. The best conserved and most widely distributed of these involve Atx1-like chaperones and P_1B-type ATPase transporters. Here, we discuss current understanding of how these chaperones bind Cu(I) and transfer it to the Atx1-like N-terminal domains of their cognate transporter.     

Temporal and spatial differences in the emission of calls by pipistrelle bats<Emphasis Type="Italic">Pipistrellus pipistrellus</Emphasis> and<Emphasis Type="Italic">P. pygmaeus</Emphasis>

The number of orientation, feeding and social calls emitted by pipistrelle batsPipistrellus pipistrellus Schreber, 1774 andP. pygmaeus Leach, 1825 was recorded throughout the night at eight different sites. Social calls were unaffected by weather variables, whereas orientation calls and feeding buzzes were both significantly affected by cloud and temperature conditions. The number of emissions of each call type was significantly different between sites, indicating that the bats used different sites for different activities. Significant positive correlations between all three combinations of call types occurred only during the middle of the night, corresponding with the nadir of flying insects. This suggests that bats were engaged in activities other than feeding at this time, such as territory protection or mate attraction.     

Current clinical laboratory practice: investigation of plasma lipids--which tests and when?

Clinical interest in the lipoproteins stems mainly from the association between serum cholesterol concentrations and coronary heart disease. Investigations of lipoproteins should be performed in patients with premature coronary heart disease, with a strong family history of coronary heart disease, or with certain cutaneous stigmata of hyperlipoproteinaemia and when fasting serum samples are seen to be lipaemic. Family studies should be performed in appropriate cases to identify relatives at increased risk of developing coronary heart disease. Patients with conditions known to cause secondary hyperlipoproteinaemia should be investigated if they fall into one of these categories but only after treatment of the underlying condition. Non-specialist laboratories should be able to measure total cholesterol and triglyceride concentrations and high density lipoprotein cholesterol concentrations. Lipoprotein electrophoresis has a limited role in such laboratories and is not necessary as a routine procedure. Specialist laboratories should in addition be able to measure individual lipoproteins and identify apolipoprotein E phenotypes.     

Sickness and Healing: An Anthropological Perspective

Sickness and Healing: An Anthropological Perspective. Robert A. Hahn. New Haven, CT: Yale University Press, 1995 (cloth and paper), viii. 327 pp.