Journal of Toxins http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Effect of Temperature on Production of Ochratoxin A by Aspergillus niger in Orange Juice Tue, 28 Jan 2014 10:44:18 +0000 http://www.hindawi.com/journals/jtox/2014/947806/ This challenging study was carried out to evaluate the temporal production of ochratoxin A (OTA) by Aspergillus niger ATCC 16404 and wild type A. niger AM at different temperatures in fresh squeezed orange juice (Citrus sinensis [L.] Osbeck cv Tarocco). Each strain, inoculated into the filtered orange juice, was incubated at 4°C, 20°C, and 26°C for 28 days. In the juice, at 26°C and 20°C, the concentration of A. niger ATCC 16404 increased by more than 2 log10 up to the 21st day. At 4°C it remained constant. The microbial load of A. niger AM decreased at all temperatures. At 26°C, the maximum OTA accumulation found was 3.44 ng/mL on the 21st day for A. niger ATCC 16404 and 8. 44 ng/mL on the 7th day for A. niger AM. The OTA synthesis seemed to be an intrinsic strain-dependent mechanism. A. niger ATCC 16404 produced OTA in accordance with the higher temperatures and the biomass concentrations, whereas A. niger AM produced the toxin at all temperatures regardless of its biomass. These results showed that fresh orange juice contaminated with Aspergillus niger aggregate strains may contain OTA levels. Andreana Marino, Caterina Fiorentino, Francesca Spataro, and Antonia Nostro Copyright © 2014 Andreana Marino et al. All rights reserved. Convulsive and Neurodegenerative Effects in Rats of Some Isolated Toxins from the Tityus bahiensis Scorpion Venom Thu, 24 Oct 2013 13:38:32 +0000 http://www.hindawi.com/journals/jtox/2013/501876/ Despite Tityus bahiensis being one of the most dangerous scorpions in Brazil, there are few studies about the effects of its venom, which acts mainly on the central nervous system. Previous studies demonstrated the convulsive ability of this venom. The present work aimed to study the hippocampal effects in rats of some toxins isolated from pool V, which induces a pronounced epileptogenic effect. The pool was separated by reverse-phase HPLC, and the peaks with higher yield (Tb V-1, V-5, V-24, V-27, and V-28) were used in the experiments. Cannulae and electrodes were implanted in the hippocampus of male Wistar rats (240–250 g). The animals were divided into six groups that received intracerebral injection of toxin solution (1 or 2 μg/μL) or Ringer solution (control group), and they were submitted to behavioral, electrographic, and histological analysis. All toxins studied evoked electrographic and behavioral epileptic-like activity to different degrees. Moreover, the toxins V-1, V-24, and V-28 caused significant neuronal loss in CA4 ipsi- and contralateral hippocampal areas. These results suggest that toxins from T. bahiensis scorpion, when injected into the hippocampus, are able to act directly on the central nervous system inducing convulsive and neurodegenerative effects. Luciene Toshie Takeishi Ossanai, Geane Antiques Lourenço, Ivo Lebrun, Ana Leonor Abrahão Nencioni, and Valquiria Abrão Coronado Dorce Copyright © 2013 Luciene Toshie Takeishi Ossanai et al. All rights reserved. Biochemical and Pharmacological Characterization of TLBbar, a New Serine Protease with Coagulant Activity from Bothrops barnetti Snake Venom Wed, 31 Jul 2013 16:10:50 +0000 http://www.hindawi.com/journals/jtox/2013/207170/ A thrombin-like enzyme named TLBbar was isolated from Bothrops barnetti snake venom and its biochemical and pharmacological characteristics were determined. TLBbar was purified using size exclusion chromatography and reverse phase HPLC, showing molecular mass of 28750.7 Da determined by mass spectrometry. TLBbar serine protease is basic (pI 7.4) and its structure shows similarity with other serine proteases of snake venom. Optimal proteolytic activity was at 37°C and pH 8; this activity was strongly inhibited by PMSF and Leupeptin, however; heparin, and soybean trypsin inhibitor (SBT-I) were ineffective. Kinetic studies on BApNA chromogenic substrate have revealed that TLBbar presents a Michaelis-Menten kinetics, with values of and of 0.433 mM and 0.42 nmol/min, respectively. TLBbar showed high clotting activity upon bovine and human plasma, presenting IC of 125 and minimum dose coagulant (MDC) of 2.23 μg/μL. TLBbar cleavages the Aα chain of bovine fibrinogen, with maximal efficiency at 30–40°C in the presence of calcium after two hours incubation; this fibronogenolityc activity was inhibited by PMSF and Leupeptin, confirming its classification in the group of serine proteases. In addition, TLBbar is capable of aggregating platelets in the same way that thrombin in concentrations of 2.5 μg/μL. Magaly Alejandra Brousett-Minaya, Paulo Aparecido Baldasso, Salomón Huancahuire-Vega, and Sérgio Marangoni Copyright © 2013 Magaly Alejandra Brousett-Minaya et al. All rights reserved. Purification and Characterization of a Nonenzymatic Neurotoxin from Hippasa partita (Lycosidae) Spider Venom Gland Extract Thu, 13 Jun 2013 09:35:51 +0000 http://www.hindawi.com/journals/jtox/2013/720150/ India is a habitat for nearly one thousand four hundred forty-seven species of spiders under three hundred and sixty-five genera and sixty families. Our initial survey on toxic bite by spider revealed severe edema, itching, acute pain, and hemorrhage following tissue necrosis, which are the general symptoms of envenomation, but there are no reports of mortality. Significantly, Hippasa partita spider, commonly called “funnel web spider,” which is endemic in hilly regions of the Western Ghats is responsible for envenomation. In this study, a nonenzymatic neurotoxin has been purified from H. partita venom gland extract. Gel filtration and ion exchange chromatography were used to purify the toxin into homogeneity as shown by SDS-PAGE, RP-HPLC, and MALDI-TOF. Neurotoxin is devoid of enzymatic activities but causes intense neurotoxic symptoms. Neurotoxin is found to inhibit the twitch response of sciatic nerve gastrocnemius muscle preparation and is found to be postsynaptic in action. Neurotoxin is devoid of coagulant activity, edema, and hemorrhage and is nonlethal to mice (up to 5 mg/kg body weight). In conclusion, a neurotoxin, which is a principle agent in whole venom responsible for induced neurotoxic symptoms, has been purified and characterized. S. Nagaraju and K. Kemparaju Copyright © 2013 S. Nagaraju and K. Kemparaju. All rights reserved. Anthrax Lethal Toxin Inhibits the Production of Proinflammatory Cytokines Wed, 27 Mar 2013 11:21:04 +0000 http://www.hindawi.com/journals/jtox/2013/476909/ In previous studies, we have found that anthrax lethal toxin (LeTx) induces apoptosis in both murine macrophages and human peripheral blood mononuclear cells (PBMCs). In this study, we further report that bacterial cell wall (CW) components of Bacillus (B.) anthracis are powerful inducers of proinflammatory cytokines from the PBMCs. These effects are deprived when the LeTx is present. The major causative element for this suppression is lethal factor (LF) rather than protective antigen (PA). These results indicate that the roles of LeTx in anthrax pathogenesis, particularly its effects on cytokine production, should be reevaluated as our findings and other reports are controversial to the conventional concept. Aiguo Wu, Joseph Shiloach, Darya Alibek, Lydia Yue Li, Christopher Bradburne, and Ken Alibek Copyright © 2013 Aiguo Wu et al. All rights reserved.