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Entiauspe-Neto OM, Nachtigall PG, Borges-Martins M, Junqueira-de-Azevedo ILM, Grazziotin FG. Highly conserved and extremely variable: The paradoxical pattern of toxin expression revealed by comparative venom-gland transcriptomics of Phalotris (Serpentes: Dipsadidae). Toxicon 2024; 244:107740. [PMID: 38705487 DOI: 10.1016/j.toxicon.2024.107740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/11/2024] [Accepted: 04/27/2024] [Indexed: 05/07/2024]
Abstract
Although non-front fanged snakes account for almost two-thirds of snake diversity, most studies on venom composition and evolution focus exclusively on front-fanged species, which comprise most of the clinically relevant accidents. Comprehensive reports on venom composition of non-front fanged snakes are still scarce for several groups. In this study, we address such shortage of knowledge by providing new insights about the venom composition among species of Phalotris, a poorly studied Neotropical dipsadid genus. Phalotris are known for their specialized venom delivery system and toxic venoms, which can cause life-threatening accidents in humans. We evaluate the venom-gland transcriptome of Phalotris, comparing the following three South American species: P. reticulatus for the Araucaria Pine forests, P. lemniscatus for the Pampa grasslands, and P. mertensi for the Brazilian Cerrado. Our results indicate similar venom profiles, in which they share a high expression level of Kunitz-type inhibitors (KUNZ). On the other hand, comparative analyses revealed substantial differences in the expression levels of C-type lectins (CTL) and snake venom metalloproteinases (SVMP). The diverse set of SVMP and CTL isoforms shows signals of positive selection, and we also identified truncated forms of type III SVMPs, which resemble type II and type I SVMPs of viperids. Additionally, we identified a CNP precursor hosting a proline-rich region containing a BPP motif resembling those commonly detected in viperid venoms with hypotensive activity. Altogether, our results suggest an evolutionary history favoring high expression levels of few KUNZ isoforms in Phalotris venoms, contrasting with a highly diverse set of SVMP and CTL isoforms. Such diversity can be comparable with the venom variability observed in some viperids. Our findings highlight the extreme phenotypic diversity of non-front fanged snakes and the importance to allocate greater effort to study neglected groups of Colubroidea.
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Affiliation(s)
- Omar M Entiauspe-Neto
- Laboratório de Coleções Zoológicas, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil; Programa de Pós-graduação em Biologia Animal, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, CEP 91501-970, Porto Alegre, RS, Brazil.
| | - Pedro G Nachtigall
- Laboratório de Toxinologia Aplicada, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil
| | - Márcio Borges-Martins
- Programa de Pós-graduação em Biologia Animal, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, CEP 91501-970, Porto Alegre, RS, Brazil
| | | | - Felipe G Grazziotin
- Laboratório de Coleções Zoológicas, Instituto Butantan, 05503-900, Av. Vital Brazil, 1500, Butantã, São Paulo, SP, Brazil
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DNA barcodes from snake venom: a broadly applicable method for extraction of DNA from snake venoms. Biotechniques 2018; 65:339-345. [PMID: 30477329 DOI: 10.2144/btn-2018-0096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
DNA barcoding is a simple technique used to develop a large-scale system of classification that is broadly applicable across a wide variety of taxa. DNA-based analysis of snake venoms can provide a system of classification independent of currently accepted taxonomic relationships by generating DNA barcodes specific to each venom sample. DNA purification from dried snake venoms has previously required large amounts of starting material, has resulted in low yields and inconsistent amplification, and was possible with front-fanged snakes only. Here, we present a modified DNA extraction protocol applied to venoms of both front- and rear-fanged snakes that requires significantly less starting material (1 mg) and yields sufficient amounts of DNA for successful PCR amplification of regions commonly used for DNA barcoding. [Formula: see text].
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Suntrarachun S, Chanhome L, Sumontha M. Phylogenetic analysis of the king cobra, Ophiophagus hannah in Thailand based on mitochondrial DNA sequences. ASIAN BIOMED 2017. [DOI: 10.5372/1905-7415.0802.289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Background: Snakes possess adaptive characteristics of morphology that may result in incorrect reconstruction of phylogeny. Molecular approaches have become the major source of new information for advancing our understanding of evolutionary, genetic relationships, and species identification.
Objective: We studied DNA sequences of Ophiophagus hannah in different parts of Thailand and compared them with those of O. hannah from other countries.
Materials and Methods: We studied the mitochondrial NADH dehydrogenase subunit 2 (ND2) and control region (CR) sequences of 12 individuals O. hannah from different localities across Thailand. Phylogenetic analysis of DNA sequences were compared to the published sequences of O. hannah deposited in NCBI GenBank database from other countries.
Results: O. hannah could be categorized into 2 Clades, 5 haplotypes, and 4 localities based on 43 different nucleotide positions from the 736 bp of ND2 and 673 bp of CR. Clade A was haplotype A from southern Thailand. Clade B consisted of haplotypes B, C, D, and E. Haplotype B and C came from northern Thailand. Haplotype D came from western Thailand, while haplotype E was O. hannah from central Thailand. The DNA sequences of Clade B were similar to the sequences of O. hannah in Myanmar and southern China that are already deposited in NCBI GenBank database.
Conclusion: We found a different genotype of O. hannah from southern Thailand and suggest that this may be a new species of O. hannah.
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Affiliation(s)
- Sunutcha Suntrarachun
- Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok 10330, Thailand
| | - Lawan Chanhome
- Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok 10330, Thailand
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