Are ticks venomous animals?

0430918 - BC 2015 RIV GB eng J - Článek v odborném periodiku
Cabezas-Cruz, A. - Valdés, James J.
Are ticks venomous animals?
Frontiers in Zoology. Roč. 11, JUL 2014 (2014), s. 47. ISSN 1742-9994. E-ISSN 1742-9994
Grant CEP: GA MŠMT(CZ) EE2.3.30.0032
Institucionální podpora: RVO:60077344
Klíčová slova: ticks * venom * secreted proteins * toxicoses * pathogens * convergence
Kód oboru RIV: EB - Genetika a molekulární biologie
Impakt faktor: 3.051, rok: 2014

Introduction: As an ecological adaptation venoms have evolved independently in several species of Metazoa. As haematophagous arthropods ticks are mainly considered as ectoparasites due to directly feeding on the skin of animal hosts. Ticks are of major importance since they serve as vectors for several diseases affecting humans and livestock animals. Ticks are rarely considered as venomous animals despite that tick saliva contains several protein families present in venomous taxa and that many Ixodida genera can induce paralysis and other types of toxicoses. Tick saliva was previously proposed as a special kind of venom since tick venom is used for blood feeding that counteracts host defense mechanisms. As a result, the present study provides evidence to reconsider the venomous properties of tick saliva. Results: Based on our extensive literature mining and in silico research, we demonstrate that ticks share several similarities with other venomous taxa. Many tick salivary protein families and their previously described functions are homologous to proteins found in scorpion, spider, snake, platypus and bee venoms. This infers that there is a structural and functional convergence between several molecular components in tick saliva and the venoms from other recognized venomous taxa. We also highlight the fact that the immune response against tick saliva and venoms (from recognized venomous taxa) are both dominated by an allergic immunity background. Furthermore, by comparing the major molecular components of human saliva, as an example of a non-venomous animal, with that of ticks we find evidence that ticks resemble more venomous than non-venomous animals. Finally, we introduce our considerations regarding the evolution of venoms in Arachnida.
Trvalý link: http://hdl.handle.net/11104/0235577