105 research outputs found

    Humoral immune response of patients bitten by the snake Bothrops erythromelas

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    INTRODUCTION: Snake envenomings are a health problem in rural areas of tropical and subtropical countries, but little is known regarding the immune response presented by bitten individuals. The IgM production of patients bitten by Bothrops erythromelas snake was analyzed to identify the effectiveness of treatment in this type of envenomation. METHODS: Bothrops erythromelas venom was submitted to electrophoresis and transferred to a nitrocellulose sheet, following incubation with patients' sera. RESULTS: A 38 KDa protein was detected before and 24 h after therapy. CONCLUSIONS: The result suggests that this protein could be used as a marker for individuals envenomed by Bothrops. erythromelas.INTRODUÇÃO: Envenenamentos ofídicos consistem problema de saúde pública em áreas rurais de países tropicais e subtropicais, mas pouco sabe-se sobre a resposta imune apresentada pelos indivíduos picados, por isso a avaliação da produção de IgM por pacientes picados por Bothrops erythromelas identificando a eficácia do tratamento nesse tipo de envenenamento. MÉTODOS: O veneno de Bothrops erythromelas foi submetido a eletroforese e transferido para nitrocelulose, seguindo incubação com soro de pacientes. RESULTADOS: Foi observada proteína de 38KDa antes e 24 horas após o tratamento. CONCLUSÕES: Os resultados sugerem que essa proteína poderia ser utilizada como marcador para indivíduos envenenados pela serpente Bothrops erythromelas

    Adaptive Evolution of the Venom-Targeted vWF Protein in Opossums that Eat Pitvipers

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    The rapid evolution of venom toxin genes is often explained as the result of a biochemical arms race between venomous animals and their prey. However, it is not clear that an arms race analogy is appropriate in this context because there is no published evidence for rapid evolution in genes that might confer toxin resistance among routinely envenomed species. Here we report such evidence from an unusual predator-prey relationship between opossums (Marsupialia: Didelphidae) and pitvipers (Serpentes: Crotalinae). In particular, we found high ratios of replacement to silent substitutions in the gene encoding von Willebrand Factor (vWF), a venom-targeted hemostatic blood protein, in a clade of opossums known to eat pitvipers and to be resistant to their hemorrhagic venom. Observed amino-acid substitutions in venom-resistant opossums include changes in net charge and hydrophobicity that are hypothesized to weaken the bond between vWF and one of its toxic snake-venom ligands, the C-type lectin-like protein botrocetin. Our results provide the first example of rapid adaptive evolution in any venom-targeted molecule, and they support the notion that an evolutionary arms race might be driving the rapid evolution of snake venoms. However, in the arms race implied by our results, venomous snakes are prey, and their venom has a correspondingly defensive function in addition to its usual trophic role

    The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins

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    Snakebite envenoming is a serious and neglected tropical disease that kills ~100,000 people annually. High-quality, genome-enabled comprehensive characterization of toxin genes will facilitate development of effective humanized recombinant antivenom. We report a de novo near-chromosomal genome assembly of Naja naja, the Indian cobra, a highly venomous, medically important snake. Our assembly has a scaffold N50 of 223.35 Mb, with 19 scaffolds containing 95% of the genome. Of the 23,248 predicted protein-coding genes, 12,346 venom-gland-expressed genes constitute the \u27venom-ome\u27 and this included 139 genes from 33 toxin families. Among the 139 toxin genes were 19 \u27venom-ome-specific toxins\u27 (VSTs) that showed venom-gland-specific expression, and these probably encode the minimal core venom effector proteins. Synthetic venom reconstituted through recombinant VST expression will aid in the rapid development of safe and effective synthetic antivenom. Additionally, our genome could serve as a reference for snake genomes, support evolutionary studies and enable venom-driven drug discovery

    Competitive binding assay for glucocorticoids. Influence of experimental conditions on measurement of the affinity of competitive steroids for the receptor.

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    Steroid derivatives for electrophilic affinity labelling of glucocorticoid binding sites: interaction with the glucocorticoid receptor and biological activity.

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