Immunoblots were scanned and analysed with ImageQuant software (Molecular Dynamics, CA, USA). Lasiodora sp. crude venom was diluted in distilled water (0.5 mg/ml) and centrifuged (2500 × g, 10 min, 4 °C) to remove insoluble materials. The venom was transferred to Vivaspin centrifugal tubes (GE Healthcare, Chalfont St. Giles, UK) with a buy GSK2118436 50 kDa molecular mass cutoff. After centrifugation (4000 × g, 10 min, 20 °C), the filtrate was put into 30 kDa cutoff tubes. The sample was centrifuged again (4000 × g, 10 min, 20 °C). Then the filtrate from 30 kDa tubes was transferred to 3 kDa cutoff tubes

and centrifuged (4000 × g, 50 min, 20 °C). Finally, the filtrate from 3 kDa tubes was collected and stored at −20 °C prior to analysis. Freeze-dried filtrate from 3 kDa cutoff tube was Selleck Gefitinib resuspended in solution A [0.1% trifluoroacetic acid

(TFA; Sigma-Aldrich) in distilled water]. Filtrate diluted to 10 times the initial volume was fractionated by reversed-phase high pressure liquid chromatography (HPLC) using an analytical C18SP column (C18 small pore; 90 Å, 5 μm, 4.6 × 250 mm; Grace Vydac, Albany, OR, USA), previously equilibrated with solution A. The sample was eluted with a gradient of solution B [0.1% TFA in acetonitrile (ACN; Merck, Darmstadt, Germany)] at a flow rate of 1 ml/min: 0-17.5% B from 10 to 15 min, 17.5-25% B from 15 to 50 min. This chromatographic procedure was monitored by absorbance at 214 nm. A vasodilator activity screening was performed using the peaks eluted in the first step of reversed-phase

chromatography, as previously described (sections 2.4 and 2.5). The absorption spectrum of the vasoactive fraction in ultraviolet (UV, 200-400 nm) was accomplished using spectrophotometer. P-type ATPase Subsequently, the vasoactive fraction from the first step of reversed-phase chromatography was diluted to 5 times the initial volume and applied to a semi-preparative C18SP column (C18 small pore; 90 Å, 5 μm, 10 × 250 mm; Grace Vydac), previously equilibrated with 2% solution B. The gradient of solution B, at a flow rate of 5 ml/min, was: 2-30% B for 75 min, 30-80% B from 75 to 85 min, 80 – 2% B from 100 to 110 min. This second step of reversed-phase chromatography was monitored by absorbance at 214 and 254 nm. All liquid chromatography analyses were performed using a Shimadzu Prominence HPLC (Shimadzu, Kyoto, Japan). The mass spectrometry (MS) analysis was executed by specialists at CEMSA (Centro de Espectrometria de Massas Aplicada, São Paulo, Brazil) using a 3200 QTRAP hybrid triple quadrupole-linear ion trap mass spectrometer equipped with a Turbo Ion Spray source (Applied Biosystems-Sciex, Framingham, MA, USA). The sample was diluted in a 1:1 water/ACN solution and positive-ion mode MS and MS/MS analyses were assayed.