The Muscini flies of the world (Diptera, Muscidae): identification key and generic diagnoses

Flies of the tribe Muscini (Diptera, Muscidae) are worldwide in distribution and are represented by some 350 species in 18 genera. The present study provides an identification key and diagnoses for all the genera of world Muscini: Biopyrellia Townsend, Curranosia Paterson, Dasyphora Robineau-Desvoidy, Deltotus Seguy, Hennigmyia Peris, Mesembrina Meigen, Mitroplatia Enderlein, Morellia Robineau-Desvoidy, Musca Linnaeus, Myiophaea Enderlein, Neomyia Walker, Neorypellia Pont, Polietes Rondani, Polietina Schnabl & Dziedzicki, Pyrellia Robineau-Desvoidy, Pyrellina Malloch, Sarcopromusca Townsend, Ziminellia Nihei & de Carvalho. Most infrageneric taxa are also represented, namely, the sub-genera of Dasyphora and Morellia. Comments on phylogeny support (whenever pertinent) and the major references containing revisions and regional identification keys to species are provided for each genus and subgenus.

Defect centre responsible for production of 110 degrees C TL peak in quartz

110 degrees C thermoluminescence (TL) peak in quartz is well known due to its pre-dose effect, which is used in dating technique. The generally accepted mechanism for the production of this peak is based on Ge impurity contained in quartz. Its role is to substitute for Si in SiO(4) tetrahedron and under irradiation gives rise to [GeO(4)/e(-)](-) electron centre. Heating for TL read out liberates electron that recombines with hole in [AlO(4)/h]degrees or [H(3)O(4)/h]degrees centres emitting photon. The investigation, carried out on blue quartz, green quartz, black quartz, pink quartz, red quartz, sulphurous quartz, milky quartz, alpha quartz and synthetic quartz, has shown that the 110 degrees C TL peak in all these varieties of quartz has no correlation with the respective Ge content. Electron paramagnetic resonance (EPR) measurements on any of these varieties of quartz revealed a signal with g(1) = 2.0004, g(2) = 1.9986 and g(3) = 1.974 and this signal does not appear to correspond to any known EPR signals in alpha quartz. Furthermore, isothermal decay measurements are carried out on the above mentioned EPR signal and 110 degrees C TL peak in alpha, blue and green quartz. A close correlation has been observed in the decay behavior. A new mechanism is proposed based on an interstitial O(-) centre. (C) 2009 Elsevier Ltd. All rights reserved.

First chemoenzymatic synthesis of organoselenium amines and amides

A series of organoselenium amines have been synthesized and submitted to the enzymatic kinetic resolution by acetylation mediated by CAL-B (Novozym 435) to give the corresponding chiral amides in an enantiomerically pure form. After evaluating the appropriate lipase, solvent, temperature,and lipase/substrate ratio in the kinetic resolution, the chiral organoselenium amides were obtained with enantiomeric excess of up to 99%. (C) 2008 Elsevier Ltd. All rights reserved.

Docking and molecular dynamics simulation of quinone compounds with trypanocidal activity

In this work, two different docking programs were used, AutoDock and FlexX, which use different types of scoring functions and searching methods. The docking poses of all quinone compounds studied stayed in the same region in the trypanothione reductase. This region is a hydrophobic pocket near to Phe396, Pro398 and Leu399 amino acid residues. The compounds studied displays a higher affinity in trypanothione reductase (TR) than glutathione reductase (GR), since only two out of 28 quinone compounds presented more favorable docking energy in the site of human enzyme. The interaction of quinone compounds with the TR enzyme is in agreement with other studies, which showed different binding sites from the ones formed by cysteines 52 and 58. To verify the results obtained by docking, we carried out a molecular dynamics simulation with the compounds that presented the highest and lowest docking energies. The results showed that the root mean square deviation (RMSD) between the initial and final pose were very small. In addition, the hydrogen bond pattern was conserved along the simulation. In the parasite enzyme, the amino acid residues Leu399, Met400 and Lys402 are replaced in the human enzyme by Met406, Tyr407 and Ala409, respectively. In view of the fact that Leu399 is an amino acid of the Z site, this difference could be explored to design selective inhibitors of TR.