Search results for "Polymer"
showing 10 items of 10504 documents
Double copies of blaKPC-3::Tn4401a on an IncX3 plasmid in Klebsiella pneumoniae successful clone ST512 from Italy
2015
ABSTRACT A carbapenem-resistant sequence type 512 (ST512) Klebsiella pneumoniae carbapenemase 3 (KPC-3)-producing K. pneumoniae strain showing a novel variant plasmid content was isolated in Palermo, Italy, in 2014. ST512 is a worldwide successful clone associated with the spread of bla KPC genes located on the IncFIIk pKpQIL plasmid. In our ST512 strain, the bla KPC-3 gene was unusually located on an IncX3 plasmid, whose complete sequence was determined. Two copies of bla KPC-3 ::Tn 4401a caused by intramolecular transposition events were detected in the plasmid.
Dioxomolybdenum(VI) and -Tungsten(VI) Amino Bisphenolates as Epoxidation Catalysts
2016
Low-cost metallate salts Na2MO4·2H2O (M = molybdenum, tungsten) react with a tridentate amine bisphenol bis(2-hydroxy-3-tert-butyl-5-methylbenzyl)methylamine (H2ONOtBu) under ambient conditions in acidic methanol solutions. The reactions lead to the formation of isostructural dioxo complexes [MO2(ONOtBu)(MeOH)]·MeOH in convenient yields. Spectral data as well as X-ray analyses reveal these complexes to be isostructural. Both compounds were tested as catalysts for epoxidation of olefins using cis-cyclooctene, cyclohexene, norbornene and styrene as substrates and tert-butyl hydroperoxide and hydrogen peroxide as oxidants. The molybdenum complex catalyses selectively the oxidation of cis-cyclo…
Tracking mite trophic interactions by multiplex PCR
2020
Background A thorough knowledge of trophic webs in agroecosystems is essential to achieve successful biological pest control. Phytoseiid mites are the most efficient natural enemies of tetranychid mites, which include several important pests worldwide. Nevertheless, phytoseiids may feed on other food sources including other microarthropods, plants and even other phytoseiids (intraguild predation), which can interfere with biological control services. Molecular gut content analysis is a valuable tool for characterizing trophic interactions, mainly when working on microarthropods such as mites. We have designed new primers for Phytoseiidae, Tetranychidae and Thysanoptera identification and th…
Identification of mycorrhiza-regulated genes with arbuscule development-related expression profile
2004
Suppressive subtractive hybridisation was applied to the analysis of late stage arbuscular mycorrhizal development in pea. 96 cDNA clones were amplified and 81, which carried fragments more than 200 nt in size, were sequence analysed. Among 67 unique fragments, 10 showed no homology and 10 were similar to sequences with unknown function. RNA accumulation of the corresponding 67 genes was analysed by hybridisation of macro-arrays. The cDNAs used as probes were derived from roots of wild type and late mutant pea genotypes, inoculated or not with the AM fungus Glomus mosseae. After calibration, a more than 2.5-fold mycorrhiza-induced RNA accumulation was detected in two independent experiments…
Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping
2011
In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold-drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation…
Poliolefiny i środowisko
2006
Przedstawiono znaczenie, rozwój metod otrzymywania, kierunki zastosowania i perspektywy rozwoju poliolefin (głównie polietylenu i polipropylenu), materiałów dominujących w światowej produkcji i zużyciu tworzyw sztucznych. Scharakteryzowano oddziaływania tych polimerów na środowisko, kolejno w etapie ich wytwarzania, wykorzystywania i utylizacji odpadów poużytkowych.
Single-chain antibodies against a plant viral RNA-dependent RNA polymerase confer virus resistance.
2004
Crop loss due to viral diseases is still a major problem for agriculture today. We present a strategy to achieve virus resistance based on the expression of single-chain Fv fragments (scFvs) against a conserved domain in a plant viral RNA-dependent RNA polymerase (RdRp), a key enzyme in virus replication. The selected scFvs inhibited complementary RNA synthesis of different plant virus RdRps in vitro and virus replication in planta. Moreover, the scFvs also bound to the RdRp of the distantly related hepatitis C virus. T(1) and T(2) progeny of transgenic lines of Nicotiana benthamiana expressing different scFvs either in the cytosol or in the endoplasmic reticulum showed varying degrees of r…
Biochemical and structural analysis of the NS5B RNA-dependent RNA polymerase of the hepatitis C virus.
2000
Hepatitis C virus (HCV), the major causative agent of chronic and sporadic non-A, non-B hepatitis worldwide, is a distinct member of the Flaviviridae virus family. These viruses have in common a plus-strand RNA genome that is replicated in the cytoplasm of the infected cell via minus-strand RNA intermediates. Owing to the lack of reliable cell culture systems and convenient animal models for HCV, the mechanisms governing RNA replication are not known. As a first step towards the development of appropriate in vitro systems, we expressed the NS5B RNA-dependent RNA polymerase (RdRp) in insect cells, purified the protein to near homogeneity and studied its biochemical properties. It is a primer…
Functional properties of a monoclonal antibody inhibiting the hepatitis C virus RNA-dependent RNA polymerase.
2001
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), represented by nonstructural protein 5B (NS5B), has recently emerged as a promising target for antiviral intervention. Here, we describe the isolation, functional characterization, and molecular cloning of a monoclonal antibody (mAb) inhibiting the HCV RdRp. This mAb, designated 5B-12B7, binds with high affinity to a conformational epitope in the palm subdomain of the HCV RdRp and recognizes native NS5B expressed in the context of the entire HCV polyprotein or subgenomic replicons. Complete inhibition of RdRp activity in vitro was observed at equimolar concentrations of NS5B and mAb 5B-12B7, whereas RdRp activities of classica…
Enhancement of hepatitis C virus RNA replication by cell culture-adaptive mutations.
2001
ABSTRACT Studies of the Hepatitis C virus (HCV) replication cycle have been made possible with the development of subgenomic selectable RNAs that replicate autonomously in cultured cells. In these replicons the region encoding the HCV structural proteins was replaced by the neomycin phosphotransferase gene, allowing the selection of transfected cells that support high-level replication of these RNAs. Subsequent analyses revealed that, within selected cells, HCV RNAs had acquired adaptive mutations that increased the efficiency of colony formation by an unknown mechanism. Using a panel of replicons that differed in their degrees of cell culture adaptation, in this study we show that adaptive…