The reaction of the cross-bridged cyclam ligand H2CBC with divalent ytterbium precursors, Yb[N(SiMe3)2]2[L]2 (L = THF or Et2O) or Yb(C5Me5)2(OEt2) afforded polymeric [Yb(CBC)]n (1), as the primary product. In addition, the Yb[N(SiMe3)2]2[L]2 reactions also afforded a small amount of an unusual mixed valence salt containing a trinuclear Yb(III) cluster cation featuring a triply bridging NH group and a mononuclear Yb(II) anion, {[Yb(CBC)]3[μ3-NH]}+ {Yb[N(SiMe3)2]3}− (2). A related cluster containing an iodide counterion, {[Yb(CBC)]3[μ3-NH]}+ I− (3), was also isolated in one case. The structures of salts 2 and 3 were determined by X-ray crystallography. Reaction of [Yb(CBC)]n with p-tolyldisulfide, (C6H4MeS)2, produced burgundy crystals of [Yb(CBC)(S-p-C6H4Me)]n (4). The 1H NMR spectra of 2 suggests that the trinuclear cation remains intact in THF-d8 solution. 相似文献
RNA silencing is a potent antiviral mechanism in plants and animals. As a counter-defense, many viruses studied to date encode one or more viral suppressors of RNA silencing (VSR). In the latter case, how different VSRs encoded by a virus function in silencing remains to be fully understood. We previously showed that the nonstructural protein Pns10 of a Phytoreovirus, Rice dwarf virus (RDV), functions as a VSR. Here we present evidence that another nonstructural protein, Pns11, also functions as a VSR. While Pns10 was localized in the cytoplasm, Pns11 was localized both in the nucleus and chloroplasts. Pns11 has two bipartite nuclear localization signals (NLSs), which were required for nuclear as well as chloroplastic localization. The NLSs were also required for the silencing activities of Pns11. This is the first report that multiple VSRs encoded by a virus are localized in different subcellular compartments, and that a viral protein can be targeted to both the nucleus and chloroplast. These findings may have broad significance in studying the subcellular targeting of VSRs and other viral proteins in viral-host interactions.
DNA barcoding has largely been tested for a wide range of taxa and evidenced as a reliable and rapid molecular tool for species-level identification. The present study lends to generate 156 DNA barcodes, of which 141 belonged to 30 morphologically identified bees from the Indian Himalayan Regions (IHRs). The generated barcode data along with 84 sequences of global database distinctly discriminated all the studied species with sufficient genetic distances and cohesive monophyletic clustering in Bayesian analysis (BA) phylogeny. The species delimitation methods, Automatic Barcode Gap Discovery (ABGD), Bayesian Poisson-Tree-Processes (bPTP), and General Mixed Yule-coalescent (GMYC) yielded 68, 70, and 71 molecular operational taxonomic units (MOTUs) respectively. The present DNA barcode-based examination detected the possible cryptic diversity in two Apis species (A. cerana and A. dorsata), Bombus hypnorum, Lepidotrigona arcifera, and Ceratina sutepensis. The present study also evidenced the species complexes within Bombus albopleuralis and Bombus trifasciatus in the IHRs. The species delimitation methods also detected an additional seven putative species from the IHRs, which were identified up to the genus level. In conclusion, this preliminary effort helps to develop a reliable barcode database of bees from the Indian IHRs to facilitate the future systematics study. These molecular data can be utilized to evaluate the population structures and assist to formulate the effective plans for bee conservation. 相似文献
Root-knot nematode, Meloidogyne incognita is considered as one of the major non-insect pests of crops. The management of these root feeders becomes highly challenging due to a strong host-parasitic relationship. Pochonia chlamydosporia is a nematophagus fungus that colonizes eggs of nematodes. This study aimed to test the efficacy of P. chlamydosporia (NAIMCC-SF0039) against M. incognita. An oil dispersion formulation of P. chlamydosporia was prepared using emulsifiers and vegetable oil. This formulation had a shelf-life of 90 days (3.3 × 108 CFU/mL) at room temperature (28 ± 1 °C). The inhibitory effect of oil formulation was tested against M. incognita by inoculating it on the egg mass. We found that colonization of the gelatinous matrix occurred on the third day of inoculation followed by complete egg parasitization on the seventh day. A greenhouse trial was laid out to evaluate the biocontrol potential of P. chlamydosporia in cucumber (Cucumis sativus). The results showed that the application of talc formulation of P. chlamydosporia at the rate of 1 kg per acre during planting, followed by delivery of 1 L of oil dispersion formulation through drip lines at 30-day intervals caused the highest reduction of nematode infestation. This treatment recorded 67.9 and 57.5% reduction in egg masses and soil nematode population respectively than that of control. 相似文献
In Al-Madinah Al-Munawwarah region, Kingdom of Saudi Arabia, Culex pipiens is considered one of the most common mosquitoes. Owing to their exceptional chemical, physical, biological, and eco-friendly properties, ionic liquids (ILs) have been recently considered promising compounds in managing a variety of organisms. Six aminopyridinium-based IL derivatives were assessed to follow their efficacy against adults of C. pipiens. Mosquitoes were treated with aminopyridinium-based IL derivatives either orally or by spraying. It was observed in the first three days of treatment that the accumulated mortality rates were generally higher in sprayed mosquitoes with IL derivatives than their accumulated mortality rates in orally treated mosquitoes with the same ILs. It was also observed that the accumulated mortalities of sprayed mosquitoes at 0.125 and 0.25 g/L were higher than those in mosquitoes orally treated with the same concentrations. The highest mortality rates were 64 and 80% for sprayed and orally treated mosquitoes, respectively. The mode of action of aminopyridinium-based IL derivatives was tracked, and it is demonstrated to be through the digestive route for orally treated mosquitoes. This is the first study to show the adulticidal effects of aminopyridinium-based ILs in controlling C. pipiens. 相似文献
Figs and fig pollinators are one of the few classic textbook examples of obligate pollination mutualism. The specific dependence of fig pollinators on the relatively safe living environment with sufficient food sources in the enclosed fig syconia implies that they are vulnerable to habitat changes. However, there is still no extensive genomic evidence to reveal the evolutionary footprint of this long-term mutually beneficial symbiosis in fig pollinators. In fig syconia, there are also non-pollinator species. The non-pollinator species differ in their evolutionary and life histories from pollinators. We conducted comparative analyses on 11 newly sequenced fig wasp genomes and one previously published genome. The pollinators colonized the figs approximately 66.9 million years ago, consistent with the origin of host figs. Compared with nonpollinators, many more genes in pollinators were subject to relaxed selection. Seven genes were absent in pollinators in response to environmental stress and immune activation. Pollinators had more streamlined gene repertoires in the innate immune system, chemosensory toolbox, and detoxification system. Our results provide genomic evidence for the differentiation between pollinators and nonpollinators. The data suggest that owing to the long-term adaptation to the fig, some genes related to functions no longer required are absent in pollinators. 相似文献