The spider family Sicariidae includes three genera,
Hexophthalma,
Sicarius and
Loxosceles. The three genera share a common characteristic in their venoms: the presence of Sphingomyelinases D (SMase D). SMases D are considered the toxins that cause the main pathological effects of
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The spider family Sicariidae includes three genera,
Hexophthalma,
Sicarius and
Loxosceles. The three genera share a common characteristic in their venoms: the presence of Sphingomyelinases D (SMase D). SMases D are considered the toxins that cause the main pathological effects of the
Loxosceles venom, that is, those responsible for the development of loxoscelism. Some studies have shown that
Sicarius spiders have less or undetectable SMase D activity in their venoms, when compared to
Hexophthalma. In contrast, our group has shown that
Sicarius ornatus, a Brazilian species, has active SMase D and toxic potential to envenomation. However, few species of
Sicarius have been characterized for their toxic potential. In order to contribute to a better understanding about the toxicity of
Sicarius venoms, the aim of this study was to characterize the toxic properties of male and female venoms from
Sicarius tropicus and compare them with that from
Loxosceles laeta, one of the most toxic
Loxosceles venoms. We show here that
S. tropicus venom presents active SMases D. However, regarding hemolysis development, it seems that these toxins in this species present different molecular mechanisms of action than that described for
Loxosceles venoms, whereas it is similar to those present in bacteria containing SMase D. Besides, our results also suggest that, in addition to the interspecific differences, intraspecific variations in the venoms’ composition may play a role in the toxic potential of venoms from
Sicarius species.
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