No abstract

Oxytropis and Astragalus represent one of the largest angiosperm genera complexes. Although phylogenetic studies of this complex exist, the evolutionary relationships among Astragalus and Oxytropis species sharing similar habitats in the Old World have not been studied in detail. The phylogenetic relationships among 13 Oxytropis and 56 Astragalus species native to Turkey were inferred from nucleotide sequence variations in the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast maturase-like protein (matK) gene regions. In addition to our samples, 36 Oxytropis ITS and 6 Oxytropis matK sequences were retrieved from GenBank and included in the analysis. Phylogenies derived from a maximum likelihood analysis of the sequences indicated that Oxytropis and Astragalus genera are more likely monophyletic. However, the results suggest that New World Oxytropis species did not evolve by a single adaptive radiation in the genus, but rather from different Old World lineages. The genetic divergence between genera was less when the matK region was analyzed. Although the Oxytropis species did not show high genetic diversity, one subcluster of the genus was always distinctly separated in both trees. This subcluster was formed by the species Oxytropis engizekensis Duman & Vural and O. persica Boiss., which are also regarded as synonyms in regard to several morphological characters of the genus.

No abstract

To stop the COVID-19 pandemic due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which caused more than 2.5 million deaths to date, new antiviral molecules are urgently needed. The replication of SARS-CoV-2 requires the RNA-dependent RNA polymerase (RdRp), making RdRp an excellent target for antiviral agents. RdRp is a multi-subunit complex composed of 3 viral proteins named nsp7, nsp8 and nsp12 that ensure the ~30 kb RNA genome’s transcription and replication. The main strategies employed so far for the overproduction of RdRp consist of expressing and purifying the three subunits separately before assembling the complex in vitro. However, nsp12 shows limited solubility in bacterial expression systems and is often produced in insect cells. Here, we describe an alternative strategy to co-express the full SARS-CoV-2 RdRp in E. coli, using a single plasmid. Characterization of the purified recombinant SARS-CoV-2 RdRp shows that it forms a complex with the expected (nsp7)(nsp8)2(nsp12) stoichiometry. RNA polymerization activity was measured using primer-extension assays showing that the purified enzyme is functional. The purification protocol can be achieved in one single day, surpassing in speed all other published protocols. Our construct is ideally suited for screening RdRp and its variants against very large chemical compounds libraries and has been made available to the scientific community through the Addgene plasmid depository (Addgene ID: 165451).