Variation of cytochrome oxidase-I gene and venom proteins of Rhopalurus junceus populations in the Moanicum sector: Pharmacological implications

Abstract

Context: In Cuba, the venom of the endemic scorpion Rhopalurus junceus has been used in traditional medicine for cancer treatment. The genetic variability in populations from distinct origin and differences in the composition of venom –a little explored topic- could influence the pharmacological effects of products used in medical practice. Aims: To characterize the populations of R. junceus from six different districts of the Moanicum sector in northeastern Cuba, taking into account the variations in the sequences of cytochrome oxidase subunit I gene (COI) and peptide masses of venom. Methods: For the genetic characterization, a 658 bp gene fragment of COI was amplified by PCR. The genetic structure of populations was analyzed hierarchically, using an analysis of molecular variance (AMOVA). In proteomic analysis, molecular masses of venom constituents were arranged in increasing order, and different components were considered when masses differed by 2 Da. Results: R. junceus species in the six districts studied in the Moanicum sector belong to different populations. The sequences of COI gene showed high levels of genetic variability, recovering 47 haplotypes (87% unique). The composition of the venom was also significantly different between the districts. The most abundant components presented masses of 3-6 kDa (K+-channel specific peptides) and 6,1-10 kDa (Na+-channel specific peptides). Conclusions: Populations of R. junceus showed high genetic differentiation and a broad intraspecific variation in the venom peptides (3-10 kDa) in six districts of Moanicum sector of Cuba. This richness in scorpion varieties with different toxins profile should be considered for pharmacological applications.