The toxicity of Loxosceles spider venom has been attributed to a rare enzyme, sphingomyelinase D, which transforms sphingomyelin to ceramide-1-phosphate. The bases of its inflammatory and dermonecrotic activity, however, remain unclear. In this work the effects of ceramide-1-phosphate on model membranes were studied both by in situ generation of this lipid using a recombinant sphingomyelinase D...

Spider bites are not very common, especially in the Mediterranean area, and those affecting the ocular-palpebral region involving reconstructive surgery are particularly rare. In May 2010, the case of a Caucasian 24-year-old female patient was brought to the attention of the Dermatology Department, University of Cagliari, Italy. The patient reported she woke up feeling an intense pain with itch...

The periodicity of molting and resumption of feeding after molting was investigated in the brown recluse spider, Loxosceles reclusa Gertsch and Mulaik (Sicariidae). Spiders molted almost every hour of the day but there was a tendency to molt more frequently between 8 A.M. and 1 A.M. Spiderlings resumed feeding after 20 hrs post-molt with feeding occuring more frequently around the 43rd hour and...

A variety of refugia were offered to different instars of brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, and a South American recluse spider, L. laeta (Nicolet), to determine whether they preferred certain types of refugia spaces. Variables included (1) crevice widths ranging from 3.2 to 21 mm, (2) horizontal and vertical orientations, and (3) new refugia or refugia that had silk...

An 80-year-old man living in Fréjus in southern France had a cellulitis on the right arm (Figure 1). The patient had no fever, chills, systemic symptoms, or other clinical signs. He felt a slight pain in his arm during the night and while folding his arm, he crushed a spider. The spider’s body was immediately recovered and then identified by an entomologist (Figure 2). This typical skin lesion ...

In view of the widely varying compositions of fixative solutions used for studying spiders, five different fixative formulas were tested for fixing male brown-spider (Loxosceles intermedia) gonad tissues. The brown spider represents a public health problem in Curitiba (Paraná State, Brazil). Morphological study of its gonads may aid in understanding the reproductive strategies of this species, ...

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the nic...

Envenomation by Loxosceles bites is characterized by dermonecrotic and/or systemic features that lead to several clinical signs and symptoms called loxoscelism. Dermonecrotic lesions are preceded by thrombosis of the dermal plexus. Recent studies show that atheromatous plaque is prone to thrombosis due to endothelial cell apoptosis. To the best of our knowledge, there are no reports of microsco...