Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use

Derivatives of quinoxalin-2-one are interesting compounds with potential pharmacological activity. From this point of view, understanding of their electrochemical behavior is of great importance. In the present paper, a mechanism of electrochemical reduction of quinoxalin-2-one derivatives at mercury dropping electrode was proposed. Pyrazine ring was found to be the main electroactive center undergoing a pH-dependent two-electron reduction process. The molecule protonization of nitrogen in the position 4 precedes the electron acceptance forming a semiquinone radical intermediate which is relatively stable in acidic solutions. Its further reduction is manifested by separated current signal. A positive mesomeric effect of the nonprotonized amino group in the position 7 of the derivative III accelerates the semiquinone reduction yielding a single current wave. The suggested reaction mechanism was verified by means of direct current polarography, differential pulse, cyclic and elimination voltammetry, and coulometry with subsequent GC/MS analysis. The understanding of the mechanism was applied in developing of analytical method for the determination of the studied compounds

The Expanding Menagerie of Prunus-Infecting Luteoviruses

Members of the genus Luteovirus are responsible for economically destructive plant diseases worldwide. Over the past few years, three luteoviruses infecting Prunus trees have been characterized. However, the biological properties, prevalence, and genetic diversity of those viruses have not yet been studied. High-throughput sequencing of samples of various wild, cultivated, and ornamental Prunus species enabled the identification of four novel species in the genus Luteovirus for which we obtained complete or nearly complete genomes. Additionally, we identified another new putative species recovered from Sequence Read Archive data. Furthermore, we conducted a survey on peach-infecting luteoviruses in eight European countries. Analyses of 350 leaf samples collected from germplasm, production orchards, and private gardens showed that peach-associated luteovirus (PaLV), nectarine stem pitting-associated virus (NSPaV), and a novel luteovirus, peach-associated luteovirus 2 (PaLV2), are present in all countries; the most prevalent virus was NSPaV, followed by PaLV. The genetic diversity of these viruses was also analyzed. Moreover, the biological indexing on GF305 peach indicator plants demonstrated that PaLV and PaLV2, like NSPaV, are transmitted by graft at relatively low rates. No clear viral symptoms have been observed in either graft-inoculated GF305 indicators or different peach tree varieties observed in an orchard. The data generated during this study provide a broader overview of the genetic diversity, geographical distribution, and prevalence of peach-infecting luteoviruses and suggest that these viruses are likely asymptomatic in peach under most circumstances.This study was funded by the European Union through the Horizon 2020 Marie Skłodowska-Curie Actions Innovative Training Network (H2020 MSCA-60 ITN) project “INEXTVIR” (grant agreement number 813542). The ChLVA research part was financed by the Academy of Sciences of the Czech Republic (RVO60077344). The plant indexing biological tests conducted by CTIFL were funded by INTERFEL (fresh fruit and vegetable interprofessional association). D. Safarova and M. Navratil received support from the Ministry of Agriculture of the Czech Republic, National Agency for Agricultural Research (project QK1920124). M. Glasa and D. Mihálik received support from the Slovak Research & Development Agency (project APVV-18-0005)Peer reviewe

Expressed sequence tags in cancer genomics

International audienceExpressed sequence tag (EST) databases are a well established and continuously growing source to study gene expression, alternative splicing, genome sequences, gene-associated polymorphisms and sequence homologies through bioinformatic approaches. Here, we examine recent efforts to identify and characterize cancer genes and tumor markers using ESTs. Limitations of EST mining strategies and directions for future research are also summarized

Complete genome sequence of a novel bromovirus infecting elderberry (<em>Sambucus nigra L.</em>) in the Czech Republic.

The genus Bromovirus currently contains six species whose members have relatively narrow host ranges. In the present work, a new bromovirus infecting elderberry (Sambucus nigra L.) is reported. dsRNA was purified and sequenced by next-generation sequencing, and with minimal additional completion by Sanger sequencing, the full tripartite genome was obtained. RNA1 is 3241 nt long and contains ORF1 (1a protein), RNA2 is 2810 nt long and contains ORF2 (2a protein), and RNA3 is 2244 nt long and contains ORF3a (movement protein) and ORF3b (coat protein, CP), separated by an intercistronic poly(A) stretch. Proteins 1a and 2a showed highest sequence identity (69.9% and 69.4%) to the corresponding proteins of melandrium yellow fleck virus. The coat protein showed highest sequence identity (67.9%) to that of brome mosaic virus. The genome shows a typical bromovirus organisation comprising of all the conserved protein domains within the genus. Phylogenetic analysis supports the assignment of this virus as a new member of the genus Bromovirus, for which the name "sambucus virus S" (SVS) is proposed

Molecular characterization of a novel Aureusvirus infecting elderberry (<em>Sambucus nigra</em> L.).

A novel virus infecting elderberry was identified by high-throughput Illumina sequencing of double strand RNAs isolated form elderberry leaves. The complete genome sequence obtained (4512 nucleotides in length) shows an organization typical for aureusviruses, with five open reading frames (ORFs) and the typical ORF1-RT expression by the readthrough of an amber stop codon. The analysis of the RNA-dependent RNA polymerase (RdRp) and coat protein (CP) sequences showed the highest identity (respectively 75.7% and 55%) with the corresponding amino acid sequences of Pothos latent virus. These two values, below the species demarcation criteria for the genus, indicate that the detected virus is a new member of genus Aureusvirus, family Tombusviridae, with the proposed name Elderberry aureusvirus 1 (ElAV1). A survey confirmed the wide distribution of ElAV1 in elderberry in the Czech Republic. Phylogenetic analyses of RdRp and CP sequences showed distinct microevolution of geographically separated isolates, with a tendency for isolates coming from close localities or from the same region to cluster together but heterogeneity of viral populations down to a local scale was also observed. The symptomatology of the new virus is not fully clear, but many infected trees were either asymptomatic or showed mild chlorotic mosaics. More severe symptoms, potentially impacting yields of flowers or berries, were observed in plants with mixed infections of ElAV1 and other elderberry viruses. Further efforts are now needed to determine ElAV1 prevalence outside the Czech Republic and to unravel its epidemiology