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Understanding Biological Roles of Venoms Among the Caenophidia: The Importance of Rear-Fanged Snakes.
Integr Comp Biol 2016; 56(5):1004-1021IC

Abstract

Snake venoms represent an adaptive trophic response to the challenges confronting a limbless predator for overcoming combative prey, and this chemical means of subduing prey shows several dominant phenotypes. Many front-fanged snakes, particularly vipers, feed on various vertebrate and invertebrate prey species, and some of their venom components (e.g., metalloproteinases, cobratoxin) appear to have been selected for "broad-brush" incapacitation of different prey taxa. Using proteomic and genomic techniques, the compositional diversity of front-fanged snakes is becoming well characterized; however, this is not the case for most rear-fanged colubroid snakes. Because these species consume a high diversity of prey, and because venoms are primarily a trophic adaptation, important clues for understanding specific selective pressures favoring venom component composition will be found among rear-fanged snake venoms. Rear-fanged snakes typically (but not always) produce venoms with lower complexity than front-fanged snakes, and there are even fewer dominant (and, arguably, biologically most relevant) venom protein families. We have demonstrated taxon-specific toxic effects, where lizards and birds show high susceptibility while mammals are largely unaffected, for both Old World and New World rear-fanged snakes, strongly indicating a causal link between toxin evolution and prey preference. New data are presented on myotoxin a, showing that the extremely rapid paralysis induced by this rattlesnake toxin is specific for rodents, and that myotoxin a is ineffectual against lizards. Relatively few rear-fanged snake venoms have been characterized, and basic natural history data are largely lacking, but directed sampling of specialized species indicates that novel compounds are likely among these specialists, particularly among those species feeding on invertebrate prey such as scorpions and centipedes. Because many of the more than 2200 species of colubroid snakes are rear-fanged, and many possess a Duvernoy's venom gland, understanding the nature of their venoms is foundational to understanding venom evolution in advanced snakes.

Authors+Show Affiliations

School of Biological Sciences, University of Northern Colorado, 501 20th St, Greeley, CO 80639-0017, USA stephen.mackessy@unco.edu.School of Biological Sciences, University of Northern Colorado, 501 20th St, Greeley, CO 80639-0017, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27639275

Citation

Mackessy, Stephen P., and Anthony J. Saviola. "Understanding Biological Roles of Venoms Among the Caenophidia: the Importance of Rear-Fanged Snakes." Integrative and Comparative Biology, vol. 56, no. 5, 2016, pp. 1004-1021.
Mackessy SP, Saviola AJ. Understanding Biological Roles of Venoms Among the Caenophidia: The Importance of Rear-Fanged Snakes. Integr Comp Biol. 2016;56(5):1004-1021.
Mackessy, S. P., & Saviola, A. J. (2016). Understanding Biological Roles of Venoms Among the Caenophidia: The Importance of Rear-Fanged Snakes. Integrative and Comparative Biology, 56(5), pp. 1004-1021.
Mackessy SP, Saviola AJ. Understanding Biological Roles of Venoms Among the Caenophidia: the Importance of Rear-Fanged Snakes. Integr Comp Biol. 2016;56(5):1004-1021. PubMed PMID: 27639275.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Understanding Biological Roles of Venoms Among the Caenophidia: The Importance of Rear-Fanged Snakes. AU - Mackessy,Stephen P, AU - Saviola,Anthony J, Y1 - 2016/09/17/ PY - 2016/9/18/pubmed PY - 2018/4/12/medline PY - 2016/9/18/entrez SP - 1004 EP - 1021 JF - Integrative and comparative biology JO - Integr. Comp. Biol. VL - 56 IS - 5 N2 - Snake venoms represent an adaptive trophic response to the challenges confronting a limbless predator for overcoming combative prey, and this chemical means of subduing prey shows several dominant phenotypes. Many front-fanged snakes, particularly vipers, feed on various vertebrate and invertebrate prey species, and some of their venom components (e.g., metalloproteinases, cobratoxin) appear to have been selected for "broad-brush" incapacitation of different prey taxa. Using proteomic and genomic techniques, the compositional diversity of front-fanged snakes is becoming well characterized; however, this is not the case for most rear-fanged colubroid snakes. Because these species consume a high diversity of prey, and because venoms are primarily a trophic adaptation, important clues for understanding specific selective pressures favoring venom component composition will be found among rear-fanged snake venoms. Rear-fanged snakes typically (but not always) produce venoms with lower complexity than front-fanged snakes, and there are even fewer dominant (and, arguably, biologically most relevant) venom protein families. We have demonstrated taxon-specific toxic effects, where lizards and birds show high susceptibility while mammals are largely unaffected, for both Old World and New World rear-fanged snakes, strongly indicating a causal link between toxin evolution and prey preference. New data are presented on myotoxin a, showing that the extremely rapid paralysis induced by this rattlesnake toxin is specific for rodents, and that myotoxin a is ineffectual against lizards. Relatively few rear-fanged snake venoms have been characterized, and basic natural history data are largely lacking, but directed sampling of specialized species indicates that novel compounds are likely among these specialists, particularly among those species feeding on invertebrate prey such as scorpions and centipedes. Because many of the more than 2200 species of colubroid snakes are rear-fanged, and many possess a Duvernoy's venom gland, understanding the nature of their venoms is foundational to understanding venom evolution in advanced snakes. SN - 1557-7023 UR - https://www.unboundmedicine.com/medline/citation/27639275/Understanding_Biological_Roles_of_Venoms_Among_the_Caenophidia:_The_Importance_of_Rear_Fanged_Snakes_ L2 - https://academic.oup.com/icb/article-lookup/doi/10.1093/icb/icw110 DB - PRIME DP - Unbound Medicine ER -