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Aird SD, Aggarwal S, Villar-Briones A, Tin MMY, Terada K, Mikheyev AS. Snake venoms are integrated systems, but abundant venom proteins evolve more rapidly. BMC Genomics 2015; 16:647. [PMID: 26315097 PMCID: PMC4552096 DOI: 10.1186/s12864-015-1832-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 08/07/2015] [Indexed: 12/19/2022] Open
Abstract
Background While many studies have shown that extracellular proteins evolve rapidly, how selection acts on them remains poorly understood. We used snake venoms to understand the interaction between ecology, expression level, and evolutionary rate in secreted protein systems. Venomous snakes employ well-integrated systems of proteins and organic constituents to immobilize prey. Venoms are generally optimized to subdue preferred prey more effectively than non-prey, and many venom protein families manifest positive selection and rapid gene family diversification. Although previous studies have illuminated how individual venom protein families evolve, how selection acts on venoms as integrated systems, is unknown. Results Using next-generation transcriptome sequencing and mass spectrometry, we examined microevolution in two pitvipers, allopatrically separated for at least 1.6 million years, and their hybrids. Transcriptomes of parental species had generally similar compositions in regard to protein families, but for a given protein family, the homologs present and concentrations thereof sometimes differed dramatically. For instance, a phospholipase A2 transcript comprising 73.4 % of the Protobothrops elegans transcriptome, was barely present in the P. flavoviridis transcriptome (<0.05 %). Hybrids produced most proteins found in both parental venoms. Protein evolutionary rates were positively correlated with transcriptomic and proteomic abundances, and the most abundant proteins showed positive selection. This pattern holds with the addition of four other published crotaline transcriptomes, from two more genera, and also for the recently published king cobra genome, suggesting that rapid evolution of abundant proteins may be generally true for snake venoms. Looking more broadly at Protobothrops, we show that rapid evolution of the most abundant components is due to positive selection, suggesting an interplay between abundance and adaptation. Conclusions Given log-scale differences in toxin abundance, which are likely correlated with biosynthetic costs, we hypothesize that as a result of natural selection, snakes optimize return on energetic investment by producing more of venom proteins that increase their fitness. Natural selection then acts on the additive genetic variance of these components, in proportion to their contributions to overall fitness. Adaptive evolution of venoms may occur most rapidly through changes in expression levels that alter fitness contributions, and thus the strength of selection acting on specific secretome components. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1832-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Steven D Aird
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Shikha Aggarwal
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan. .,University School of Environment Management, Guru Gobind Singh Indraprastha University, Sector 16C, Dwarka, New Delhi, 110078, India.
| | - Alejandro Villar-Briones
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Mandy Man-Ying Tin
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan.
| | - Kouki Terada
- Okinawa Prefectural Institute of Health and the Environment, Biology and Ecology Group, 2003 Ozato, Ozato, Nanjo-shi, Okinawa, 901-1202, Japan.
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology Graduate University, Tancha 1919-1, Onna-son, Kunigami-gun, Okinawa-ken, 904-0412, Japan. .,Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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Gomes A, Choudhury SR, Saha A, Mishra R, Giri B, Biswas AK, Debnath A, Gomes A. A heat stable protein toxin (drCT-I) from the Indian Viper (Daboia russelli russelli) venom having antiproliferative, cytotoxic and apoptotic activities. Toxicon 2007; 49:46-56. [PMID: 17055549 DOI: 10.1016/j.toxicon.2006.09.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 09/09/2006] [Accepted: 09/12/2006] [Indexed: 10/24/2022]
Abstract
A heat stable 7.2kDa protein toxin (drCT-I) has been purified and crystallized from Indian Daboia russelli russelli venom (Roy Choudhury et al., 2006. Acta Cryst. F Struct Biol Cryst Commun, 62(Pt. 3), 292). The N-terminal (first 20) amino acid sequence of drCT-I was LKCNKLVPLFYKTCPAGKNL, which showed sequence homology to cytotoxins isolated from Naja venom. drCT-I has been evaluated for anticancer activity against EAC cells in vivo and human leukemic cells (U937, K562) in vitro. drCT-I (125 microg/kg, i.p/day for 10 days) significantly decreased EAC cell count, cell viability (p<0.001) and significantly increased the survival time of tumour bearing mice (T/C% 178.64, p<0.01) in comparison to untreated tumour bearing control. drCT-I, produced dose and time-dependent inhibition of U937 and K562 cell growth and had an IC50 of 8.9 and 6.7 microg/ml respectively after 24h treatment. The reduced MTT values after drCT-I treatment indicated its cytotoxic nature, which supported its antiproliferative action. Scanning electron microscopy and confocal microscopy in U937 and K562 cells after drCT-I treatment indicated certain features of apoptosis such as membrane blebbing, perforations, nuclear fragmentation. The induction of apoptosis was further confirmed by phosphatidylserine externalization observed using annexinV-FITC/PI staining and flow cytometric analysis. drCT-I brought about apoptosis by G1 phase arrest of the cell cycle. The effect of drCT-I on normal human peripheral blood mononuclear cell (PBMNC) viability and cytotoxicity was studied in culture and was found to be lower than that on U937 and K562 cells. Thus both in vivo and in vitro experimental results suggested that drCT-I possessed anticancer potential.
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Affiliation(s)
- Antony Gomes
- Laboratory of Toxinology and Experimental Pharmacodynamics, Department of Physiology, University of Calcutta, 92 A. P. C. Road, Kolkata 700 009, India.
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Abstract
Many experimental studies have been carried out using snake venoms for the treatment of animal tumors, with controversial results. While some authors have reported an antitumor effect of treatment with specific snake venom fractions, others have reported no effects after this treatment. The aim of this study was to evaluate the effect of Bothrops jararaca venom (BjV) on Ehrlich ascites tumor (EAT) cells in vivo and in vitro. In the in vivo study, Swiss mice were inoculated with EAT cells by the intraperitoneal (i.p.) route and treated with BjV venom (0.4 mg/kg, i.p.), on the 1st, 4th, 7th, 10th, and 13th days. Mice were evaluated for total and differential cells number on the 2nd, 5th, 8th, 11th and 14th days. The survival time was also evaluated after 60 days of tumor growth. In the in vitro study, EAT and normal peritoneal cells were cultivated in the presence of different BjV concentrations (2.5, 5.0, 10.0, 20.0, 40.0, and 80 microg) and viability was verified after 3, 6, 12 and 24 h of cultivation. Results were analyzed statistically by the Kruskal-Wallis and Tukey tests at the 5% level of significance. It was observed that in vivo treatment with BjV induced tumor growth inhibition, increased animal survival time, decreased mortality, increased the influx of polymorphonuclear leukocytes on the early stages of tumor growth, and did not affect the mononuclear cells number. In vitro treatment with BjV produced a dose-dependent toxic effect on EAT and peritoneal cells, with higher effects against peritoneal cells. Taken together, our results demonstrate that BjV has an important antitumor effect. This is the first report showing this in vivo effect for this venom.
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Affiliation(s)
- Reinaldo J da Silva
- Departamento de Parasitologia, Instituto de Biociências, Universidade Estadual Paulista - UNESP, Botucatu, São Paulo, Brasil
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Omori-Satoh T, Izumi N, Yamanaka T, Kawaguchi S, Takahashi M, Takano S, Sadahiro S, Kondo S, Kondo H. Purification and characterization of cytotoxic factors in the venom of the Okinawa habu (Trimeresurus flavoviridis). Toxicon 1986; 24:1045-53. [PMID: 3105121 DOI: 10.1016/0041-0101(86)90131-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Two cytotoxic factors in the venom of Okinawa habu (Trimeresurus flavoviridis), a crotalid, have been purified and characterized. They had cell monolayer-disrupting activity against cells cultivated in vitro, but no proteolytic, hemorrhagic or direct hemolytic activity nor lethal toxicity. They were heat labile acidic proteins (isoelectric points 5.2 and 5.4) having similar molecular weights (approx. 14,000) and amino acid compositions. They were indistinguishable immunologically.
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