Intraspecies variation in the venom of the rattlesnake Crotalus simus from Mexico: Different expression of crotoxin results in highly variable toxicity in the venoms of three subspecies
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2013-07Author
Castro, Edgar Neri
Lomonte, Bruno
Gutiérrez, María del Carmen
Alagón Cano, Alejandro
Gutiérrez, José María
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The composition and toxicological profile of the venom of the rattlesnake Crotalus simus in
Mexico was analyzed at the subspecies and individual levels. Venoms of the subspecies C. s.
simus, C. s. culminatus and C. s. tzabcan greatly differ in the expression of the heterodimeric
neurotoxin complex ‘crotoxin’, with highest concentrations in C. s. simus, followed by C. s.
tzabcan, whereas the venom of C. s. culminatus is almost devoid of this neurotoxic PLA2. This
explains the large variation in lethality (highest in C. s. simus, which also exerts higher
myotoxicity). Coagulant activity on plasma and fibrinogen occurs with the venoms of C. s.
simus and C. s. tzabcan, being absent in C. s. culminatus which, in turn, presents higher
crotamine-like activity. Proteomic analysis closely correlates with toxicological profiles, since
the venom of C. s. simus has high amounts of crotoxin and of serine proteinases, whereas the
venomof C. s. culminatus presents higher amounts of metalloproteinases and crotamine. This
complex pattern of intraspecies venom variation provides valuable information for the
diagnosis and clinicalmanagement of envenoming by this species in Mexico, as well as for the
preparation of venom pools for the production and quality control of antivenoms.
Biological significance
This study describes the variation in venomcomposition and activities of the three subspecies
of Crotalus simus fromMexico. Results demonstrate that there is a notorious difference in these
venoms, particularly regarding the content of the potent neurotoxic phospholipase A2 complex
‘crotoxin’. In addition, other differences were observed regarding myotoxic and coagulant
activities, and expression of the myotoxin ‘crotamine’. These findings have implications in, at
least, three levels: (a) the adaptive role of variations in venom composition; (b) the possible
differences in the clinical manifestations of envenomings by these subspecies in Mexico; and
(c) the design of venom mixtures for the preparation of antivenoms effective in the
neutralization of the venoms of the three subspecies.
External link to the item
10.1016/j.jprot.2013.05.024Collections
- Microbiología [1170]