The Russell’s viper (Daboia siamensis) is a medically important venomous snake in Myanmar. Next-generation sequencing (NGS) shows potential to investigate the venom complexity, giving deeper insights into snakebite pathogenesis and possible drug discoveries. mRNA from venom gland tissue was extracted and sequenced on the Illumina HiSeq platform and de novo assembled by Trinity. The candidate toxin genes were identified via the Venomix pipeline. Protein sequences of identified toxin candidates were compared with the previously described venom proteins using Clustal Omega to assess the positional homology among candidates. Candidate venom transcripts were classified into 23 toxin gene families including 53 unique full-length transcripts. C-type lectins (CTLs) were the most highly expressed, followed by Kunitz-type serine protease inhibitors, disintegrins and Bradykinin potentiating peptide/C-type natriuretic peptide (BPP-CNP) precursors. Phospholipase A₂, snake venom serine proteases, metalloproteinases, vascular endothelial growth factors, L-amino acid oxidases and cysteine-rich secretory proteins were under-represented within the transcriptomes. Several isoforms of transcripts which had not been previously reported in this species were discovered and described. Myanmar Russell’s viper venom glands displayed unique sex-specific transcriptome profiles which were correlated with clinical manifestation of envenoming. Our results show that NGS is a useful tool to comprehensively examine understudied venomous snakes.

Despite the advancements in targeted therapy for BRAFV600E-mutated metastatic colorectal cancer (mCRC), the development of resistance to BRAFV600E inhibition limits the response rate and durability of the treatment. Better understanding of the resistance mechanisms to BRAF inhibitors will facilitate the design of novel pharmacological strategies for BRAF-mutated mCRC. The aim of this study was to identify novel protein candidates involved in acquired resistance to BRAFV600E inhibitor vemurafenib in BRAFV600E-mutated colon cancer cells using an integrated proteomics approach. Bioinformatic analysis of obtained proteomics data indicated actin-cytoskeleton linker protein ezrin as a highly ranked protein significantly associated with vemurafenib resistance whose overexpression in the resistant cells was additionally confirmed at the gene and protein level. Ezrin inhibition by NSC305787 increased anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant cells in an additive manner, which was accompanied by downregulation of CD44 expression and inhibition of AKT/c-Myc activities. We also detected an increased ezrin expression in vemurafenib-resistant melanoma cells harbouring the BRAFV600E mutation. Importantly, ezrin inhibition potentiated anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant melanoma cells in a synergistic manner. Altogether, our study suggests a role of ezrin in acquired resistance to vemurafenib in colon cancer and melanoma cells carrying the BRAFV600E mutation and supports further pre-clinical and clinical studies to explore the benefits of combined BRAF inhibitors and actin-targeting drugs as a potential therapeutic approach for BRAFV600E-mutated cancers.

Functional coupling and comparative genomics analysis have been applied to study functional associations of orthologs of enterococcal cAD1 sex pheromone (P13268) known to be responsible for biofilm formation, conjugative plasmid transfer and spreading of bacterial antibiotics resistance. cAD1 peptide pheromone is released from the membrane lipoprotein with the peptide precursor encoded by a gene cad (tr|C2JQE7). Our analysis of genomic neighbourhood of cad and motifs of the encoded polypeptide and its orthologs suggests a close functional association between cAD1 and ApbE protein (Q82Z24), a FMN insertion and trafficking facilitator. The cad and apbE orthologs were coupled in the genomes and ApbE-specific motifs for FMN covalent attachment were identified in cad-encoded protein sequence and its orthologs. These findings suggest a potential role of FMN-based reductase function of the cAD1 lipoprotein precursor in its processing and release of the active sex pheromone peptide. They may lead to a new approach in prevention of antibiotic resistance spread via targeting sex pheromone processing chaperones or by suppression of the FMN availability and covalent binding. This methods can be also applied to a controlled evolution of bacterial pathogenicity in microbial fuel cells, as the findings suggest the crosstalk between bacterial pathogenicity and bacterial electro-activity.

Russell’s viper (Daboia siamensis) is a medically important snake in Myanmar due to its high morbidity and mortality. The genome of Myanmar Russell’s viper had not been sequenced until recently. Hence, RNA sequencing has been used to predict genes that encode this snake’s toxins. This can lead to deeper insights into the pathogenesis of envenoming and potential drug discovery. Venom glands were dissected from four adult D. siamensis specimens (two males and two females) provided by a local Myanmar snake farm. The mRNA was extracted and sequenced on the Illumina HiSeq platform, then assembled de novo using the Trinity software. Candidate toxin genes were identified using the Venomix pipeline, and their expression levels were calculated using RSEM software. The identified toxin candidates were aligned with previously described venom proteins using Clustal Omega. Candidate venom transcripts were classified into 23 toxin gene families, which included 53 unique transcripts identified as full-length sequences. Among them, 28 full-length sequences represented the eight newly identified toxin gene families in D. siamensis, including neprilysin (2), cystatin (5), waprin (1), vipericidin (1), veficolin (1), endothelial lipases (9), vespryn (ohanin) (8), and three-finger toxins (1). Their expression levels were found to be moderate to low (TPM = 1.49 to 213.37). The majority of the toxin candidates resembled typical elapid toxins, which usually exhibit neurotoxic activities and tissue damage. A smaller proportion of candidate toxin transcripts were predicted to display antimicrobial activity and anti-metastatic effects. Our results suggest their functional activities. They should be studied further for potential therapeutic applications.

In Myanmar, Russell’s viper (Daboia siamensis) bite is a significant public health problem. In this study, we expend upon our previous RNA-sequencing approach to characterize candidate toxin genes encoding D. siamensis toxins. The mRNA was extracted from Myanmar Russell’s viper venom glands. The RNAseq was performed using Illumina next-generation sequencing. Subsequently, candidate toxin transcripts were recognized by the Venomix pipeline. This study focused on 29 unique cDNA sequences representing eight newly identified venom gene families with low-to-moderate expression levels. These transcripts represented 0.088% of the total number of transcripts in the dataset. The translated protein sequences were analyzed for their conserved motifs and domains to predict their functions. They were neprilysins (bioactive peptide inactivators), cystatins (protease inhibitors with anti-metastatic activities), waprin and vipericidin (antimicrobial peptides), veficolin (platelet and complement activation), vespryns and three-finger toxins (elapid toxin homologs causing neurotoxic activity and tissue damage), and endothelial lipases (unknown function). Their functional activities should be further investigated for potential therapeutic applications, for example, in cancer or antibiotic-resistant infections.