Novel glycosylated mycosporine-like amino acids with radical scavenging activity from the cyanobacterium Nostoc commune

Mycosporine-like amino acids (MAAs) are UV absorbing pigments, and structurally distinct MAAs have been identified in taxonomically diverse organisms. Two novel MAAs were purified from the cyanobacterium Nostoc commune, and their chemical structures were characterized. An MAA with an absorption maximum at 335 nm was identified as a pentose-bound porphyra-334 derivative with a molecular mass of 478 Da. Another identified MAA had double absorption maxima at 312 and 340 nm and a molecular mass of 1050 Da. Its unique structure consisted of two distinct chromophores of 3-aminocyclohexen-1-one and 1,3-diaminocyclohexen and two pentose and hexose sugars. These MAAs had radical scavenging activity in vitro; the 1050-Da MAA contributed approximately 27% of the total radical scavenging activities in a water extract of N. commune. These results suggest that these glycosylated MAAs have multiple roles as a UV protectant and an antioxidant relevant to anhydrobiosis in N. commune. © 2011 Elsevier B.V. All rights reserved

A Particle Simulation for the Axisymmetric Pulsar Magnetosphere: II. the case of dipole field

The main issue of the pulsar magnetosphere is how the rotation power is converted into both particle beams which causes pulsed emissions, and a highly relativistic wind of electron-positron plasmas which forms surrounding nebulae shining in X-rays and TeV gamma-rays. As a sequel of the first paper (Wada & Shibata 2007), we carried out a three dimensional particle simulation for the axisymmetric global magnetosphere. We present the results of additional calculations, which are higher resolution model and higher pair creation rate cases, and a detailed analysis for the solution. We confined to demonstrate the cases of low pair creation rate, i.e., the magnetic field is fixed dipole. The radiation drag of the plasma is taken in a form with the curvature radius along the dipole magnetic field. The electrostatic interactions are calculated by a programmable special purpose computer, GRAPE-DR (Makino et al 2007). Once pair creation is onset in the outer gaps, the both signed particles begin to drift across the closed magnetic field due to radiation drag, and they create outflow. Eventually, the steady magnetosphere has outer gaps, both signed outflow of plasma and a region in which the electric field is dominant extending from the equator. In the steady state, the magnetic field made by magnetospheric current is comparable to the dipole magnetic field outside of several light radii from the star. In much more pair creation rate model, the effect of modification of the magnetic field will bring about modification of the outflow of the plasma, requiring further study with higher pair creation rate model in a subsequent paper.Comment: 18 pages, 12 figures, accepted for publication in MNRA

Infrared Spectroscopy of 15 Radio Galaxies at 2<z<2.6

Near-infrared spectra of 15 high-redshift radio galaxies (HzRGs) located at $2<z<2.6$ were obtained by the OH Airglow Suppressor spectrograph mounted on the Subaru telescope. The UV-optical line ratio diagnostic diagrams indicate that half of the observed HzRGs have extended emission-line regions with low metal abundance, photoionized by a flat-continuum active galactic nucleus such as a quasar. We also found two probable correlations between radio and rest-optical parameters: (1) HzRGs with massive hosts tend to have a redder rest-optical continuum, and (2) HzRGs with smaller radio sizes also show a redder optical continuum. On the basis of the correlations, the nature of HzRGs at $2<z<2.6$ is discussed.Comment: 23 pages, 7 figures, Corrected typos and style. Accepted for publication in ApJ (November 20, 2003

In vitro antifungal activity of Cassia fistula L. against selected pathogenic water molds

Water mold infections in both cultured and wild aquatic animals, caused by members of the genera Saprolegnia, Achlya, and Aphanomyces, have widely occurred worldwide.  Outbreaks in aquatic creatures, especially in aquacultural facilities and fish hatcheries are common problem. Cassia fistula L. has been used as medicinal plant for broad purposes including for fungal infectious diseases remedy, but efficacy against water molds is still not apparently known. The present study was aimed to investigate in vitro antifungal activity of C. fistula stem-bark alcoholic extracts against the selected pathogenic water molds isolated from fish. The results showed that the C. fistula extract was capable to kill hyphae and zoospores of Saprolegnia paracitica NJM 8604 and S. diclina NJM 0005 at levels ranging from 1,000-4,000 microg/mL evidently within 24 h-exposure, while, a level of 500 microg/mL was sufficient to kill the both stages of Aphanomyces invadans NJM 9701. In addition, the antifungal activity of C. fistula absolute alcoholic extract comparing to 50% aqueous alcoholic extract were seemingly not different. Conclusively, the C. fistula stem-bark extracts, both absolute and 50% aqueous alcoholic extractions, were effectively able to inhibit growth and kill the 3 strains of pathogenic water molds by affect throughout the 2 important, zoospore and hyphal, stages