Information processing for the organization of chemotactic behavior ofPhysarum polycephalum studied by micro-thermography

Summary The spatial and temporal pattern of oscillating temperatures on the cell surface of a plasmodial strand ofPhysarum polycephalum was measured with a sensitive thermal image camera. The longitudinal tension of the strand was studied simultaneously. In the absence of chemical stimulation, the phases of the temperature oscillation observed at various portions of the strand were entrained with almost coincidental phase. The temperature and tension oscillation were synchronized, although the phase difference between them was occasionally changed. With local chemical stimulation, the phase of the temperature oscillation advanced in the portion to which the plasmodium would be induced to migrate. The phases between temperature and tension oscillations then became constant. The mechanism by which the plasmodium processes local information of chemical stimulus to global information for the migration is discussed.     

Curcumin attenuates oxidative stress following downhill running-induced muscle damage

Downhill running causes muscle damage, and induces oxidative stress and inflammatory reaction. Recently, it is shown that curcumin possesses anti-oxidant and anti-inflammatory potentials. Interestingly, curcumin reduces inflammatory cytokine concentrations in skeletal muscle after downhill running of mice. However, it is not known whether curcumin affects oxidative stress after downhill running-induced muscle damage. Therefore, the purpose of this study was to investigate the effects of curcumin on oxidative stress following downhill running induced-muscle damage. We also investigated whether curcumin affects macrophage infiltration via chemokines such as MCP-1 and CXCL14. Male C57BL/6 mice were divided into four groups; rest, rest plus curcumin, downhill running, or downhill running plus curcumin. Downhill running mice ran at 22 m/min, −15% grade on the treadmill for 150 min. Curcumin (3 mg) was administered in oral administration immediately after downhill running. Hydrogen peroxide concentration and NADPH-oxidase mRNA expression in the downhill running mice were significantly higher than those in the rest mice, but these variables were significantly attenuated by curcumin administration in downhill running mice. In addition, mRNA expression levels of MCP-1, CXCL14 and F4/80 reflecting presence of macrophages in the downhill running mice were significantly higher than those in the rest mice. However, MCP-1 and F4/80 mRNA expression levels were significantly attenuated by curcumin administration in downhill running mice. Curcumin may attenuate oxidative stress following downhill running-induced muscle damage.     

Preparative density gradient centrifugation of RNA and DNA in cesium sulfateurea mixture

A new procedure is described for a large scale separation and purification of unfixed DNA and RNA from a mixture of partially extracted nucleic acids and lysates of subcellular fractions by centrifugation to equilibrium in cesium sulfate-urea mixture. Optimum conditions are described for the separation and quantative recovery of both RNA and DNA in a pure form. The procedure allows determination of peak buoyant densities of 4–5s RNA, 7–11s mRNA and total cytoplasmic RNA. The procedure also allows fractionation of small molecular weight classes of cytoplasmic RNAs from the 18s and 28s rRNAs.     

Fine structure and function of the gut epithelium of pike eel larvae

The development of the alimentary canal of pike eel, Muraenesox cinereus , that were hatched and reared in the laboratory, was examined. The larvae did not feed on zooplankton or phytoplankton and survived for 10 days. Histological and histochemical investigations showed that the alimentary canal was morphologically and functionally differentiated in 3 days after hatching and before exhaustion of the yolk. The foregut was not functional in absorption. The midgut absorptive cell was characterized by a well-developed lamellar membranous structure in the basal portion of the cytoplasm. Na¹-K¹ ATPase activity was demonstrated on the lamellar membrane of the structure. It suggests that water and solute transport is quite active in the midgut epithelium. Orally administered HRP (horseradish peroxidase) was ingested and intracellularly digested in the hindgut absorptive cells. Some of the HRP was transported, without complete digestion, into tissue spaces under the epithelium. Evidence suggests that pike eel larvae possibly utilize dissolved organic matter, including soluble macromolecules, as their nutrition sources.