IgG antibodies against phospholipase A2 from Crotalus durissus terrificus: cross-reaction with venoms from Bothrops species from Argentina

We examined the ability of IgG anti-crotalic PLA2 to cross-react with Bothrops spp. venoms, from snakes found in the northeast of Argentina. Immunoblotting and ELISA tests showed that IgG anti-crotalic PLA2 recognize antigens of bothropic venoms. Indirect hemolytic activity tests showed that the quantity of antibodies that neutralized 50% of Crotalus durissus terrificus venom (ED50: 2.1 mg IgG anti-crotalic PLA2/100 µg of venom) were also able to neutralize venom from other snakes in the following proportion: 34% of B. alternatus, 18% of B. diporus and 12% of B. jararacussu. Likewise, direct PLA2 activity neutralization tests showed a similar cross-neutralization pattern including 56% of B. alternatus, 29% of B. diporus and 30% of B. jararacussu. In addition, in a myotoxic activity neutralization test, measured by plasma activity of creatine kinase, 35% of B. alternatus venom and 26% of B. diporus venom were neutralized, while no neutralization was detected with B. jararacussu venom. This study presents original data concerning cross-reactions between bothropic venoms from Argentina and IgG anti-crotalic PLA2. Our results suggest that anti-crotalic PLA2 antibodies should not be used to neutralize PLA2 activity of B. alternatus, B. diporus and especially B. jararacussu venoms; nor to enrich commercial antivenoms against these Bothrops species

CD40, autophagy and Toxoplasma gondii

Toxoplasmagondii represents a pathogen that survives within host cells by preventing the endosomal-lysosomal compartments from fusing with the parasitophorous vacuoles. The dogma had been that the non-fusogenic nature of these vacuoles is irreversible. Recent studies revealed that this dogma is not correct. Cell-mediated immunity through CD40 re-routes the parasitophorous vacuoles to the lysosomal compartment by a process called autophagy. Autophagosome formation around the parasitophorous vacuole results in killing of the T. gondii. CD40-induced autophagy likely contributes to resistance against T. gondii particularly in neural tissue

Mechanical properties of Sn-Ag lead-free solder alloys based on the dendritic array and Ag3Sn morphology

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The aim of this experimental investigation is to evaluate the tensile properties of as-cast Sn-Ag alloys as a function of both the resulting secondary dendritic arm spacings and the morphology of the Ag3Sn IMC (intermetallic compound). This comparative experimental investigation was carried out with a view to assess the application of Sn-Ag alloys as alternative solder materials. A directional water-cooled solidification apparatus was used to obtain the as-cast samples. The resulting microstructures, ultimate and yield tensile strengths and elongation of Sn-2 wt.% Ag and Sn-3.5 wt.% Ag alloys were experimentally determined and compared with the corresponding results of the traditional Sn-40 wt.% Pb solder alloy. It was found that the Sn-Ag alloys examined comply with the compromise between compatible mechanical strength and environmental protection. (C) 2013 Elsevier B. V. All rights reserved.562194204Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAE-PEX/Funcamp (Foundation of the University of Campinas, Unicamp)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Cytotoxicity and morphological analysis of cell death induced by Bothrops venoms from the northeast of Argentina

Bothrops snake venoms have been proved toxic to a variety of cell types, in both in vivo and in vitro models. Studies on the pharmacological actions of Bothrops venoms from Argentina are relatively scarce and the direct action of the crude venoms has not been assessed using cell culture models. In this work, we investigated the cytotoxicity of crude venoms from B. alternatus and B. diporus in a skeletal muscle (C2C12) cell line, which is commonly used as a model for studying the myotoxic action of snake venom. Both venoms (1.25-50 µg/mL) induced an early and significant decrease in cell viability. The cytotoxic concentration 50 (CC50), determined three hours after exposure, revealed that B. diporus venom was significantly more cytotoxic (CC50: 2 µg/mL) than B. alternatus (CC50: 5.8 µg/mL). To investigate the cell death mechanism involved, myoblast cells were examined by phase contrast microscopy and after acridine orange and ethidium bromide fluorescence staining, respectively. Our data clearly demonstrated that an apoptotic mechanism mediated this cell line destruction. The current study aimed to provide new information on the cytotoxicity mechanisms of Argentine Bothrops snake venoms on a skeletal muscle cell line

Synergism between baltergin metalloproteinase and Ba SPII RP4 PLA(2) from Bothrops alternatus venom on skeletal muscle (C2C12) cells

Acute muscle damage, myonecrosis, is one of the main characteristics of envenoming by Bothrops genus. In this in vitro study we investigated the role of a metalloproteinase (baltergin) and an acidic phospholipase A(2) (Ba SPII RP4) in the cytotoxicity exhibited by Bothrops alternatus venom. Baltergin metalloproteinase purified from the venom exerted a toxic effect on C2C12 myoblast cells (CC50: 583.34 mu g/mL) which involved morphological alterations compatible with apoptosis/anoikis. On the contrary, the most abundant PLA(2) isolated from this venom did not exhibit cytotoxicity at times and doses tested. However, when myoblasts were treated with both enzymes together, synergic activity was demonstrated. Neutralization of the venom with specific antibodies (IgG anti-baltergin and IgG anti-PLA(2)) confirmed this synergism. (C) 2011 Elsevier Ltd. All rights reserved.592338343Secretaria General de Ciencia y Tecnica [PI B013-2010]Agencia de Promocion Cientifica y Tecnologica, FonCyT, y SGCyT UNNE [PICTO 2007-00143]Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CONICET)Secretaria General de Ciencia y Tecnica [PI B013-2010]Agencia de Promocion Cientifica y Tecnologica, FonCyT, y SGCyT UNNE [PICTO 2007-00143

Isolation and functional characterization of a new acidic PLA(2) Ba SpII RP4 of the Bothrops alternatus snake venom from Argentina

An acidic protein with phospholipase A(2) activity was purified to homogeneity from the venom of the Northeast Argentinian viperid Bothrops alternatus by two chromatographic steps: a conventional gel filtration on Sephadex G-75 and reversed phase on C18 HPLC column. A molecular mass of 14185.48 Da was determined by mass spectrometry, displaying a homodimer conformation. The kinetic assay demonstrated a catalytically active phospholipase A(2) in correspondence with Asp49 PLA(2) group. The enzyme designated Ba SpII RP4 contains an amino acid composition of 121 residues and a calculated theoretical pI value of 4.88. Amino acid sequence alignments with other Bothrops PLA(2) revealed a high degree of homology sequence (90-56%). Ba SpII RP4 did not show myotoxic activity upon muscular fibers at doses up to 100 mu g i.m. route injection or lethal response when it was i.p. injected at the hightest dose of 200 mu g. This toxin generates slight biological activities like paw edema inflammation and a delay in the clotting time, although Ba SpII RP4 exhibited catalytic activity. The primary amino acid sequence, determined a quadruple-time of flight (Q-TOF) hybrid mass spectrometer Q-TOF Ultima from Micromass (Manchester, UK) equipped with a nano Zspray source operating in a positive ion mode and tandem mass spectrum, an ESI/MS mass spectrum (TOF MS mode) "de novo amino acid sequencing", also provides more database about the small group of the non-myotoxic PLA(2)s isolated up to the present. (C) 2010 Elsevier Ltd. All rights reserved.5616474Consejo Nacional de Investigaciones Cientificas y Tecnologicas - CONICET [PIP 6298]Secretaria General de Ciencia y Tecnica [PI 051-06]Universidad Nacional del Nordeste (UNNE), ArgentinaConsejo Nacional de Investigaciones Cientificas y Tecnologicas - CONICET [PIP 6298]Secretaria General de Ciencia y Tecnica [PI 051-06