Project description:Investigation of a Malagasy endemic plant identified as Symphonia pauciflora Baker (Clusiaceae) for antiproliferative activities against the A2780 ovarian cancer cell line led to the isolation of a new compound identified as 2-(3,3-dimethylallyl)-7-methoxy-l,5,6-trihydroxy-2",2"-dimethylpyrano(6",5":3,4) xanthone (1) and the two known guttiferones A (2) and I (3). The structure elucidation of 1 was based on the analysis of its 1D and 2D NMR and mass spectral data. Compound 1 showed good antiproliferative activity with an IC50 value of 3.8 microM against the A2780 human ovarian cancer cell line, while the known guttiferone analogues (2 and 3) exhibited moderate activities with IC50 values of 8.3 microM and 7.8 microM, respectively.
Project description:Eucalyptus pauciflora (the snow gum) is a long-lived tree with high economic and ecological importance. Currently, little genomic information for E. pauciflora is available. Here, we sequentially assemble the genome of Eucalyptus pauciflora with different methods, and combine multiple existing and novel approaches to help to select the best genome assembly. We generated high coverage of long- (Nanopore, 174×) and short- (Illumina, 228×) read data from a single E. pauciflora individual and compared assemblies from 5 assemblers (Canu, SMARTdenovo, Flye, Marvel, and MaSuRCA) with different read lengths (1 and 35 kb minimum read length). A key component of our approach is to keep a randomly selected collection of ∼10% of both long and short reads separated from the assemblies to use as a validation set for assessing assemblies. Using this validation set along with a range of existing tools, we compared the assemblies in 8 ways: contig N50, BUSCO scores, LAI (long terminal repeat assembly index) scores, assembly ploidy, base-level error rate, CGAL (computing genome assembly likelihoods) scores, structural variation, and genome sequence similarity. Our result showed that MaSuRCA generated the best assembly, which is 594.87 Mb in size, with a contig N50 of 3.23 Mb, and an estimated error rate of ∼0.006 errors per base. We report a draft genome of E. pauciflora, which will be a valuable resource for further genomic studies of eucalypts. The approaches for assessing and comparing genomes should help in assessing and choosing among many potential genome assemblies from a single dataset.
