title: Functional proteomic analyses of Bothrops atrox venom reveals phenotypes associated with habitat variation in the Amazon.
abstract: Venom variability is commonly reported for venomous snakes including Bothrops atrox. Here, we compared the composition of venoms from B. atrox snakes collected at Amazonian conserved habitats (terra-firme upland forest and várzea) and human modified areas (pasture and degraded areas). Venom samples were submitted to shotgun proteomic analysis as a whole or compared after fractionation by reversed-phase chromatography. Whole venom proteomes revealed a similar composition among the venoms with predominance of SVMPs, CTLs, and SVSPs and intermediate amounts of PLA2s and LAAOs. However, when distribution of particular isoforms was analyzed by either method, the venom from várzea snakes showed a decrease in hemorrhagic SVMPs and an increase in SVSPs, and procoagulant SVMPs and PLA2s. These differences were validated by experimental approaches including both enzymatic and in vivo assays, and indicated restrictions in respect to antivenom efficacy to variable components. Thus, proteomic analysis at the isoform level combined to in silico prediction of functional properties may indicate venom biological activity. These results also suggest that the prevalence of functionally distinct isoforms contributes to the variability of the venoms and could reflect the adaptation of B. atrox to distinct prey communities in different Amazon habitats.
  
  
  
  In this report, we compared isoforms present in venoms from snakes collected at different Amazonian habitats. By means of a species venom gland transcriptome and the in silico functional prediction of each isoform, we were able to predict the principal venom activities in vitro and in animal models. We also showed remarkable differences in the venom pools from snakes collected at the floodplain (várzea habitat) compared to other habitats. Not only was this venom less hemorrhagic and more procoagulant, when compared to the venom pools from the other three habitats studied, but also this enhanced procoagulant activity was not efficiently neutralized by Bothrops antivenom. Thus, using a functional proteomic approach, we highlighted intraspecific differences in B. atrox venom that could impact both in the ecology of snakes but also in the treatment of snake bite patients in the region.
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: Leijiane F
authors.initials: LF
authors.lastname: Sousa
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: José A
authors.initials: JA
authors.lastname: Portes-Junior
authors.affiliation: Laboratório de Toxinologia, Instituto Oswaldo Cruz - IOC/FIOCRUZ, Av. Brasil, 4365, 21040-900 Rio de Janeiro, RJ, Brazil.
authors.forename: Carolina A
authors.initials: CA
authors.lastname: Nicolau
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: Juliana L
authors.initials: JL
authors.lastname: Bernardoni
authors.affiliation: Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: Milton Y
authors.initials: MY
authors.lastname: Nishiyama
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: Diana R
authors.initials: DR
authors.lastname: Amazonas
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil.
authors.forename: Luciana A
authors.initials: LA
authors.lastname: Freitas-de-Sousa
authors.affiliation: Programa de Pós-Graduação em Recursos Naturais da Amazônia, Laboratório de Bioprospecção e Biologia Experimental, Universidade Federal do Oeste do Pará - UFOPA, Rua Vera Paz, s/n, 68035-110 Santarém, PA, Brazil.
authors.forename: Rosa Hv
authors.initials: RH
authors.lastname: Mourão
authors.affiliation: Faculdades Integradas do Tapajós/Faculdade da Amazônia - FIT/UNAMA, Rua Rosa Vermelha, 335, 68010-200 Santarém, PA, Brazil.
authors.forename: Hipócrates M
authors.initials: HM
authors.lastname: Chalkidis
authors.affiliation: Laboratório de Toxinologia, Instituto Oswaldo Cruz - IOC/FIOCRUZ, Av. Brasil, 4365, 21040-900 Rio de Janeiro, RJ, Brazil. Electronic address: rhv4u@ioc.fiocruz.br.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Valente
authors.affiliation: Laboratório de Imunopatologia, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil. Electronic address: ana.moura@butantan.gov.br.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Moura-da-Silva
mesh_terms: D000818:Animals; D017837:Bothrops / Q000235:genetics / Q000378:metabolism*; D001938:Brazil; D003435:Crotalid Venoms / Q000096:biosynthesis* / Q000235:genetics; D017753:Ecosystem; D005088:Exocrine Glands / Q000378:metabolism*; D040901:Proteomics; D059467:Transcriptome / Q000502:physiology
chemical_list: D003435:Crotalid Venoms
keywords: Antivenom; Bothrops atrox; Functional proteomics; Snake; Variability; Venom