, 2007). Most venom peptides that modulate the activity of ion channels elute between 35 and 45% acetonitrile, while higher molecular mass proteins, including enzymes, elute at higher acetonitrile concentrations (Horni et al., 2001; Guette et al., 2006; Estrada et al., 2007). For this reason, and based on the present mass spectrometry mapping, two main venom component groups were separately collected: the fraction of low molecular mass (LMMF) from 10 to 45 min (0–35% ACN), and protein fraction (PF) from 45 to 74 min (35–74% ACN). The molecular GSI-IX research buy mass distribution profile of the A. paulensis

venom components was trimodal, differently from the bimodal profile obtained for the venom of 55 spiders’ species

by Escoubas and Rash (2004), in which most of the compounds (57.8%) had between 3500 and 4500 Da, and a lower amount (6.9%) was in a secondary distribution, 6500–7000 Da. The ions m/z 601.4 and 729.6, found in abundance in A. paulensis venom, correspond to those observed in the venom of Lasiodora parahybana (m/z 601.38 and 729.35), in juveniles (4 years old), adults (8 years) and older spiders (14 years), being considered as biomarkers ( Guette et al., 2006). Skinner et al. (1990) partially characterized these two acylpolyamines, named Apc600 http://www.selleckchem.com/products/Adriamycin.html and Apc728, from the venom of the tarantula Aphonopelma chalcodes. Despite the reputation of spiders, there are few reports of bites by these animals, most of them result in mild to severe pain, itching and increased sensitivity, which may persist for several hours after the bite, swelling, redness, joint stiffness and swelling of limbs, burning and cramping. In more severe cases, strong cramping and muscle spasms which can last several hours can also be observed. The pain after

the bite may be due to a combination of mechanical damage due to large chelicerae, low pH venom (usually close to 5) and effect of biogenic amines (serotonin and histamine), adenosine and ATP (Escoubas and Rash, 2004). These spiders are traded as pets and world widely kept and bred in captivity (de Haro and Jouglard, 1998), so accidents can potentially occur with some frequency. Isoconazole As far as we know, there are no reports of human deaths caused by accidents with Theraphosidae spiders worldwide. On the other hand, some studies have demonstrated significant toxicity of Theraphosidae venoms in various animals, including rats, mice, cats, birds and dogs (Bucherl, 1971; Bettini and Brignoli, 1978; Atkinson, 1993). There are several reports of canine and feline fatalities provoked by Australian theraphosid spiders, such as Selenocosmia spp. ( Robinson and Griffin, 1985; Raven, 2000). There are few quantitative studies reporting the toxicity of the spider venom.