BackgroundCommonly known as blister beetles or Spanish fly, there are more than 1500 species in the Meloidae family (Hexapoda: Coleoptera: Tenebrionoidea) that produce the potent defensive blistering agent cantharidin. Cantharidin and its derivatives have been used to treat cancers such as liver, stomach, lung, and esophageal cancers. Hycleus cichorii and Hycleus phaleratus are the most commercially important blister beetles in China due to their ability to biosynthesize this potent vesicant. However, there is a lack of genome reference, which has hindered development of studies on the biosynthesis of cantharidin and a better understanding of its biology and pharmacology.ResultsWe report 2 draft genomes and quantified gene sets for the blister beetles H. cichorii and H. phaleratus, 2 complex genomes with >72% repeats and approximately 1% heterozygosity, using Illumina sequencing data. An integrated assembly pipeline was performed for assembly, and most of the coding regions were obtained. Benchmarking universal single-copy orthologs (BUSCO) assessment showed that our assembly obtained more than 98% of the Endopterygota universal single-copy orthologs. Comparison analysis showed that the completeness of coding genes in our assembly was comparable to other beetle genomes such as Dendroctonus ponderosae and Agrilus planipennis. Gene annotation yielded 13 813 and 13 725 protein-coding genes in H. cichorii and H. phaleratus, of which approximately 89% were functionally annotated. BUSCO assessment showed that approximately 86% and 84% of the Endopterygota universal single-copy orthologs were annotated completely in these 2 gene sets, whose completeness is comparable to that of D. ponderosae and A. planipennis.ConclusionsAssembly of both blister beetle genomes provides a valuable resource for future biosynthesis of cantharidin and comparative genomic studies of blister beetles and other beetles.

CYP4B1 belongs to the mammalian CYP4 enzyme family and is predominantly expressed in the lungs of humans. It is responsible for the oxidative metabolism of a wide range of endogenous compounds and xenobiotics. In this study, using data from The Cancer Genome Atlas (TCGA) project and the Gene Expression Omnibus (GEO) database, a secondary analysis was performed to explore the expression profile of CYP4B1, as well as its prognostic value in patients with lung adenocarcinoma (LUAD). Based on the obtained results, a significantly decreased CYP4B1 expression was discovered in patients with LUAD when compared with their normal counterparts (p<0.05), and was linked to age younger than 65 years (p = 0.0041), history of pharmaceutical (p = 0.0127) and radiation (p = 0.0340) therapy, mutations in KRAS/EGFR/ALK (p = 0.0239), and living status of dead (p = 0.0026). Survival analysis indicated that the low CYP4B1 expression was an independent prognostic indicator of shorter survival in terms of overall survival (OS) and recurrence-free survival (RFS) in patients with LUAD. The copy number alterations (CNAs) and sites of cg23440155 and cg23414387 hypermethylation might contribute to the decreased CYP4B1 expression. Gene set enrichment analysis (GSEA) suggested that CYP4B1 might act as an oncogene in LUAD by preventing biological metabolism pathways of exogenous and endogenous compounds and enhancing DNA replication and cell cycle activities. In conclusion, CYP4B1 expression may serve as a valuable independent prognostic biomarker and a potential therapeutic target in patients with LUAD.

Background: More than 2500 species belong to the Meloidae family (Coleoptera: Tenebrionoidea), members of which produce the potent defensive blistering agent cantharidin and are commonly known as blister beetles or Spanishflies. Cantharidin has recently been used for cancer therapy. Hycleus cichorii and Hycleus phaleratus have been used in traditional Chinese medicine for more than 2000 years due to their ability to biosynthesize cantharidin. To understand the role of the chemosensory system in beetle evolution, we comparatively analysed the chemosensory receptor families of both blister beetle species and compared them with those of other beetles. Results: We identified 89 odorant receptors (ORs), 86 gustatory receptors (GRs), and 45 ionotropic receptors (IRs) in H. phaleratus and 149 ORs, 102 GRs and 50 IRs in H. cichorii. Nine groups of beetle ORs were recovered, and a similar pattern of ORs in Coleoptera emerged. Two evident expanded clades in Hycleus (Groups 5A and 3) were reconstructed in the phylogenetic tree. Four of eight genes with evidence of positive selection were clustered in the expanded clades of Group 5A. Three, eight and three orthologous pairs of CO 2 , sugar and fructose receptors, respectively, were identified in both blister beetles. Two evident expanded clades of putative bitter GRs in Hycleus were also found, and the GR in one clade had notably low divergence. Interestingly, IR41a was specifically expanded in blister beetles compared to other insects identified to date, and IR75 was also clearly expanded in both blister beetles based on our phylogenetic tree analysis. Moreover, evidence of positive selection was detected for eight ORs, three GRs and two IRs, half of which were from five duplicate clades. Conclusions: We first annotated the chemosensory receptor families in a pair of sister beetle genomes (Meloidae: Hycleus), which facilitated evolutionary analysis of chemosensory receptors between sibling species in the Coleoptera group. Our analysis suggests that changes in chemosensory receptors have a possible role in chemicalbased species evolution in blister beetles. Future studies should include more species to verify this correlation, which will help us understand the evolution of blister beetles.

In humans, RNA editing causes nucleotide substitutions in RNA as compared to the corresponding DNA sequence. Of all 12 possible types of nucleotide substitutions, adenine-toinosine (A-to-I) editing prevails with a clearly defined biological mechanism. In more detail, A-to-I RNA-editing is mediated by adenosine deaminase acting on RNA (ADAR) 1

The Hycleus cichorii and Hycleus phaleratus are two species of medicinal meloids widely distributed in southwest of China. We sequenced an annotated the complete mitochondrial genomes of H. cichorii and H. phaleratus , and the mitogenomes are 15,847 and 16,004 bp in length, respectively. Every mitochondrial genome encodes 13 proteins, 2 ribosomal RNAs, 22 tRNAs, and a control region with the identical arrangement to other beetles. The preliminary phylogenetic analysis with mitochondrial genomes of nine meloid species further confirmed the status of these two species.

Background: Commonly known as blister beetles or Spanish fly, there are more than 1,500 species in the Meloidae family (Coleoptera:Tenebrionoidea) that produce the potent defensive blistering agent cantharidin, which has recently been exploited for cancer therapy. Hycleus cichorii and Hycleus phaleratus are exploited as traditional Chinese medicine over 2,000 years due to their ability to biosynthesize cantharidin. These blister beetles share highly similar environments and ecological niches. To understand the role of the chemosensory system in speciation and evolution in the beetles, we identified the chemosensory gene families in whole genome of both blister beetle comprehensively. Results: We identified 29 OBPs, 10 CSPs, 116 ORs, 80 GRs, and 35 IRs in H. phaleratus and 30 OBPs, 10 CSPs, 191 ORs, 92 GRs and 42 IRs in H. cichorii. The 7 groups of beetles’ ORs were recovered, but a new pattern of ORs in Coleoptera were surfaced, due to lack of whole OR repertoire for comparison to T. castaneum before. The OR number is varied, identified in H. cichorii 64% more than that in H. phaleratus (191 VS 116), which maybe an evolution event between these blister beetle’s speciation. A major Hycleus-specific expansion clade of bitter GRs is evident based on our phylogenetic tree, in which, clustered more than 50% Hycleus-bitter GRs. All the ten clade of beetles’ antennal IR identified in both Hycleus beetles. Interestingly, IR75 and IR41a were obviously expensed compare to other insects. Conclusions: The GR and IR expansion events may promote Hycleus genus evolution. Our data will provide a basis for future species protection and speciation focusing on the blister beetle.