English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Background  The spider family Sicariidae includes two genera,  Sicarius  and  Loxosceles . Bites by  Sicarius  are uncommon in humans and, in Brazil, a single report is known of a 17-year old man bitten by a  Sicarius  species that developed a necrotic lesion similar to that caused by  Loxosceles . Envenomation by  Loxosceles  spiders can result in dermonecrosis and severe ulceration.  Sicarius  and  Loxosceles  spider venoms share a common characteristic,  i.e. , the presence of Sphingomyelinases D (SMase D). We have previously shown that  Loxosceles  SMase D is the enzyme responsible for the main pathological effects of the venom. Recently, it was demonstrated that  Sicarius  species from Africa, like  Loxosceles  spiders from the Americas, present high venom SMase D activity. However, despite the presence of SMase D like proteins in venoms of several New World  Sicarius  species, they had reduced or no detectable SMase D activity. In order to contribute to a better understanding about the toxicity of New World  Sicarius  venoms, the aim of this study was to characterize the toxic properties of male and female venoms from the Brazilian  Sicarius ornatus  spider and compare these with venoms from  Loxosceles  species of medical importance in Brazil.    Methodology/Principal Findings  SDS-PAGE analysis showed variations in the composition of  Loxosceles  spp. and  Sicarius ornatus  venoms. Differences in the electrophoretic profiles of male and female venoms were also observed, indicating a possible intraspecific variation in the composition of the venom of  Sicarius  spider. The major component in all tested venoms had a Mr of 32–35 kDa, which was recognized by antiserum raised against  Loxosceles  SMases D. Moreover, male and female  Sicarius ornatus  spiders' venoms were able to hydrolyze sphingomyelin, thus showing an enzymatic activity similar to that determined for  Loxosceles  venoms.  Sicarius ornatus  venoms, as well as  Loxosceles  venoms, were able to render erythrocytes susceptible to lysis by autologous serum and to induce a significant loss of human keratinocyte cell viability; the female  Sicarius ornatus  venom was more efficient than male.    Conclusion  We show here, for the first time, that the Brazilian  Sicarius ornatus  spider contains active Sphingomyelinase D and is able to cause haemolysis and keratinocyte cell death similar to the South American  Loxosceles  species, harmful effects that are associated with the presence of active SMases D. These results may suggest that envenomation by this  Sicarius  spider has the potential to cause similar pathological events as that caused by  Loxosceles  envenomation. 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 the New World  Sicarius  venoms species.

Venom of the Brazilian Spider Sicarius ornatus (Araneae, Sicariidae) Contains Active Sphingomyelinase D: Potential for Toxicity after Envenomation