Pseudorutile-leucoxene-quartz ores of Timan ‒ a new genetic type of titanium raw materials: prospects for industrial development

The two largest deposits of Russia – Yaregskoye and Pizhemskoye belong to the same genetic type; hydrothermal-metamorphic indigenous deposits. They are located in the same Timan structure at a distance of no more than 230 km from each other. According to the total approved reserves and forecast resources of titanium dioxide, they are approaching 60% of the all-Russian and will form the basis of industrial titanium raw materials used in Russia in the near future. In the interests of technological mineralogy, morphological features, internal structure, chemical composition of grains of the two main titanium mineral phases ‒ leucoxene and pseudorutile, TiO2 polymorphs, as well as the composition of mineral microinclusions in these phases have been studied in detail. The compositions of all mineral phases in polished preparations of leucoxene and pseudorutile were analyzed by SEM-EDS method at the Institute of Geology and Geochronology of the Precambrian of the RAS, 147 chemical analyses were obtained at the point (3 µk) and many images of polished grains of anatase, leucoxene and pseudorutile were scanned over the area (20×20 µk). In the leucoxene grains themselves, 12 mineral phases were diagnosed and characterized in the form of inclusions: pseudorutile, rutile, anatase, quartz, hydromuscovite-illite, kaolinite, siderite, zircon, xenotime, pyrite, florencite, monazite and kularite. TiO2 polymorphs are verified by Raman spectroscopy and X-ray diffraction analysis. New evidence has been obtained that the transformation of ilmenite into leucoxene occurs hydrothermally through intermediate phases ‒ Fe-rutile and pseudorutile; the enlargement of rutile crystals in the leucoxene grain itself is shown; the presence of secondary crystals of siderite, florencite and others inside the studied grains

MicroRNA-134 regulates poliovirus replication by IRES targeting

Abstract Global poliovirus eradication efforts include high vaccination coverage with live oral polio vaccine (OPV), surveillance for acute flaccid paralysis, and OPV “mop-up” campaigns. An important objective involves host-directed strategies to reduce PV replication to diminish viral shedding in OPV recipients. In this study, we show that microRNA-134-5p (miR-134) can regulate Sabin-1 replication but not Sabin-2 or Sabin-3 via direct interaction with the PV 5′UTR. Hypochromicity data showed miR-134 binding to Sabin-1 and 3 but not Sabin-2 IRES. Transfection of a miR-134 mimic repressed translation of Sabin-1 5′UTR driven luciferase validating the mechanism of miR-134-mediated repression of Sabin-1. Further, site directed mutagenesis of the miR-134 binding site in Sabin-1 IRES relieved miR-134-mediated repression indicating that these regulatory molecules have an important role in regulating the host gene response to PV. Binding of miR-134 to Sabin-1 IRES caused degradation of the IRES transcript in a miR-134 and sequence specific manner. The miR-134 binding site was found to be highly conserved in wild type PV-1 as well as EV71 strains indicating that miR-134 may regulate function of these IRES sequences in circulation

Non-coding RNAs as regulators of embryogenesis

Non-coding RNAs (ncRNAs) are emerging as key regulators of embryogenesis. They control embryonic gene expression by several means, ranging from microRNA-induced degradation of mRNAs to long ncRNA-mediated modification of chromatin. Many aspects of embryogenesis seem to be controlled by ncRNAs, including the maternal–zygotic transition, the maintenance of pluripotency, the patterning of the body axes, the specification and differentiation of cell types and the morphogenesis of organs. Drawing from several animal model systems, we describe two emerging themes for ncRNA function: promoting developmental transitions and maintaining developmental states. These examples also highlight the roles of ncRNAs in ensuring a robust commitment to one of two possible cell fates