Endogenous metabolism of Polyporus sulfureus. : Utilization of exogenous carbohydrates and fatty acids

A strain of Polyporus sulfureus from the collection at the University of Missouri at Rolla was used in this investigation. Organisms of this genus have been reported to produce eburicoic acid in good yield and this was confirmed for the organism used in this study by the isolation and identification of eburicoic acid from the mycelium. Growth studies of this organism showed that 4% malt extract is a better medium than synthetic media containing asparagine, nitrate or nitrate plus 0.5% yeast extract as nitrogen sources. An examination of the pH of the culture medium led to the conclusion that regardless of whether or not the medium was buffered good growth of the organism caused a decrease in the pH of the medium. Eburicoic acid present in the mycelium of this organism did not account for this decrease in the pH of the medium. Conventional manometric techniques were used for the respiratory studies. Substrates labeled with ¹⁴C were used as a supplement to this technique. Results from these experiments indicated that this organism cannot utilize glucose directly as an energy source. Acetate and succinate stimulated oxygen uptake of the mycelium of this organism whereas pyruvate inhibited it. The reason for pyruvate inhibition of respiration in this organism is not known but certain possible causes are discussed. The R.Q. value for P. sulfureus was about 0.8. This suggested that an endogenous storage material of the oxidation state of lipid was bing utilized rather than carbohydrates. Results from work with ¹⁴C labeled glucose indicated that the pentose cycle in this organism had preference over the glycolytic pathway --Abstract, page ii-iii

A WENO Algorithm of the Temperature and Ionization Profiles around a Point Source

We develop a numerical solver for radiative transfer problems based on the weighted essentially nonoscillatory (WENO) scheme modified with anti-diffusive flux corrections, in order to solve the temperature and ionization profiles around a point source of photons in the reionization epoch. Algorithms for such simulation must be able to handle the following two features: 1. the sharp profiles of ionization and temperature at the ionizing front (I-front) and the heating front (T-front), and 2. the fraction of neutral hydrogen within the ionized sphere is extremely small due to the stiffness of the rate equations of atom processes. The WENO scheme can properly handle these two features, as it has been shown to have high order of accuracy and good convergence in capturing discontinuities and complicated structures in fluid as well as to be significantly superior over piecewise smooth solutions containing discontinuities. With this algorithm, we show the time-dependence of the preheated shell around a UV photon source. In the first stage the I-front and T-front are coincident, and propagate with almost the speed of light. In later stage, when the frequency spectrum of UV photons is hardened, the speeds of propagation of the ionizing and heating fronts are both significantly less than the speed of light, and the heating front is always beyond the ionizing front. In the spherical shell between the I- and T-fronts, the IGM is heated, while atoms keep almost neutral. The time scale of the preheated shell evolution is dependent on the intensity of the photon source. We also find that the details of the pre-heated shell and the distribution of neutral hydrogen remained in the ionized sphere are actually sensitive to the parameters used. The WENO algorithm can provide stable and robust solutions to study these details.Comment: 24 pages, 7 figures, accepted in New Astronom

Poly[[[silver(I)-μ-1,4-bis­[(imidazol-1-yl)meth­yl]benzene-κ2 N 3:N 3′-silver(I)-μ-1,4-bis­[(imidazol-1-yl)meth­yl]benzene-κ2 N 3:N 3′] 4,4′-diazenediyldibenzoate] dihydrate]

In the title compound, [Ag2(C14H14N4)2](C14H8N2O4)·2H2O, each of the two unique Ag+ ions is two-coordinated by two N atoms from two different 1,4-bis­[(imidazol-1-yl)meth­yl]benzene ligands in an almost linear fashion [N—Ag—N = 170.34 (10) and 160.25 (10)°]. The 4,4′-diazenediyldibenzoate anions do not coordinate to Ag. O—H⋯O hydrogen bonds stabilize the crystal structure

A WENO Algorithm for the Radiative Transfer and Ionized Sphere at Reionization

We show that the algorithm based on the weighted essentially nonoscillatory (WENO) scheme with anti-diffusive flux corrections can be used as a solver of the radiative transfer equations. This algorithm is highly stable and robust for solving problems with both discontinuities and smooth solution structures. We test this code with the ionized sphere around point sources. It shows that the WENO scheme can reveal the discontinuity of the radiative or ionizing fronts as well as the evolution of photon frequency spectrum with high accuracy on coarse meshes and for a very wide parameter space. This method would be useful to study the details of the ionized patch given by individual source in the epoch of reionization. We demonstrate this method by calculating the evolution of the ionized sphere around point sources in physical and frequency spaces. It shows that the profile of the fraction of neutral hydrogen and the ionized radius are sensitively dependent on the intensity of the source.Comment: Elsart Latex file, 20 pages, 8 figures included, accepted for publication in New Astronom

Production of FMDV virus-like particles by a SUMO fusion protein approach in Escherichia coli

Virus-like particles (VLPs) are formed by the self-assembly of envelope and/or capsid proteins from many viruses. Some VLPs have been proven successful as vaccines, and others have recently found applications as carriers for foreign antigens or as scaffolds in nanoparticle biotechnology. However, production of VLP was usually impeded due to low water-solubility of recombinant virus capsid proteins. Previous studies revealed that virus capsid and envelope proteins were often posttranslationally modified by SUMO in vivo, leading into a hypothesis that SUMO modification might be a common mechanism for virus proteins to retain water-solubility or prevent improper self-aggregation before virus assembly. We then propose a simple approach to produce VLPs of viruses, e.g., foot-and-mouth disease virus (FMDV). An improved SUMO fusion protein system we developed recently was applied to the simultaneous expression of three capsid proteins of FMDV in E. coli. The three SUMO fusion proteins formed a stable heterotrimeric complex. Proteolytic removal of SUMO moieties from the ternary complexes resulted in VLPs with size and shape resembling the authentic FMDV. The method described here can also apply to produce capsid/envelope protein complexes or VLPs of other disease-causing viruses