Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME) treatment on the reactive oxygen species (ROS) and on the activities of H 2 O 2 scavenging enzymes, such as superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX EC; 1.11.1.1), and guaiacol peroxidase (GPX; EC 1.11.1.7) in Ricinus communis leaves. The activity of CAT and GPX was transient while SOD activity decreased and APX increased after treatment with JAME. In addition, JAME exposure induced ROS accumulation.
BackgroundJatropha gossypiifolia L. (Euphorbiaceae) is a medicinal plant largely used in folk medicine. Teas from the leaves are popularly used as an antithrombotic agent and the branches are frequently employed as a "thick blood" agent. Considering that the anticoagulant activity associated with antioxidant properties could be beneficial for various cardiovascular diseases, this study’s aim is the evaluation of anticoagulant and antioxidant activities of J. gossypiifolia leaves, seeking new therapeutic purposes for this plant.MethodsThe aqueous leaf crude extract (CE) was prepared by decoction and was fractionated by liquid-liquid partition with solvents of increasing polarity. The phytochemical analysis was performed by thin layer chromatography (TLC) and by the spectrophotometric quantification of sugars, proteins and phenolic compounds. The anticoagulant activity was evaluated by prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests. The capacity to act in the fibrinolytic system (fibrinolytic and fibrinogenolytic activities) was also assessed. The antioxidant activity was evaluated by total antioxidant capacity, reducing power, copper chelating activity, iron chelating activity, hydroxyl radical scavenging activity and superoxide radical scavenging assays. The potential toxicity was evaluated using hemolytic assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay on HEK-293 cells.ResultsCE showed significant anticoagulant activity in aPTT test, while no action was observed in PT test, suggesting a preferential action toward the intrinsic and/or common pathway of coagulation. No effect was observed in the fibrinolytic system. Using the aPTT test, it was observed that the residual aqueous (RA) fraction was the most active, being two times more active than CE. RA presented very significant antioxidant activity in all models tested comparable to or even higher than CE. Regarding the safety, CE and RA did not produce significant cytotoxicity in both tests employed. Phytochemical analysis revealed the presence of alkaloids, flavonoids, proteins, tannins, steroids and/or terpenoids and sugars.ConclusionsCE and RA possessed significant anticoagulant and antioxidant activity and absence of cytotoxic effect in vitro, thus showing the potential of the plant, especially RA fraction, as a new source of bioactive molecules for therapeutic purposes, with particular emphasis on the treatment of cardiovascular diseases.
In order to investigate the defense response in castor bean (Ricinus communis) against predators, we analyzed the effect of mechanical wounding upon the phospholipase A 2 (PLA 2 ) activity of leaf extracts. Time course experiments revealed that the highest levels of increased PLA 2 activity (ca. two fold) occurred 15 min and 60 min after injury. The induced activities demonstrated high sensitivity towards aristolochic acid (10 mM), a PLA 2 inhibitor. Based on SDS-PAGE analysis, the PLA 2 activity induced 15 min after wounding migrated with a molecular mass of 40 kDa and was denoted RcPLA 2 I. The protein activity induced 60 min after wounding, RcPLA 2 II, migrated with a molecular weight of 14 kDa. Furthermore its N-terminal sequence shared homology with PLA 2 from elm and rice. The PLA 2 enzymes were purified to near homogeneity by a combination of gel filtration and electro-elution of protein bands after native PAGE. Key words: cellular defense, castor bean, plant signaling, phospholipase A 2 , Ricinus communis Com o objetivo de avaliar a resposta de defesa da mamona (Ricinus communis) contra predadores, analisaram-se as alterações nas atividades de fosfolipases A 2 (PLA 2 ) em extratos de folhas de plantas, submetidas à injúria mecânica após diferentes intervalos de tempo. Observou-se que os níveis dessa enzima aumentaram de forma significativa (cerca de duas vezes) 15 e 60 min após o ferimento. As atividades que foram induzidas foram sensíveis ao ácido aristolóquico (10 mM), um inibidor específico para PLA 2 . A enzima induzida após 15 min foi denominada Rc-PLA 2 I e apresentou uma massa molecular aparente, determinada por SDS-PAGE, de 40 kDa. A proteína induzida após 60 min, RcPLA 2 II, apresentou uma massa molecular de 14 kDa. A seqüência N-terminal parcial da Rc-PLAII mostrou homologia com PLA 2 de arroz e olmo. As fosfolipases foram parcialmente purificadas por associação da cromatografia de filtração em gel, seguida por eluição das bandas que apresentaram atividade enzimática após separação por PAGE não desnaturante.
Performance is one of the most important quality features in a software product. Evaluating software performance is not a trivial task because it requires not only practical knowledge of a test automation tool but also understanding of related theoretical aspects. However, the terminology regarding performance testing is quite inconsistent. In addition, the technical literature provides little information as to how performance requirements should be elicited and documented and how performance tests should be planned, implemented, and executed. This mini-course aims to present a performance testing classification as well as provide hands-on experience ranging from eliciting the performance requirement to testing using the Apache JMeter tool. ResumoO desempenho é uma das características de qualidade mais importantes em um produto de software. Avaliar o desempenho de um software não é uma tarefa trivial, pois requer não apenas conhecimento prático de uma ferramenta de automação de testes mas, também, compreensão dos aspectos teóricos relacionados. No entanto, a terminologia a respeito de testes de desempenho é bastante inconsistente. Além disso, a literatura técnica traz pouca informação a respeito de como requisitos de desempenho devem ser elicitados e documentados e como testes de desempenho devem ser planejados, implementados e executados. Este minicurso apresenta uma classificação sobre testes de desempenho e proporciona uma experiência prática cobrindo desde a elicitação do requisito de desempenho até o seu teste, utilizando a ferramenta Apache JMeter. IntroduçãoO teste de software é um processo relacionado ao desenvolvimento de software que tem como principal objetivo revelar falhas por meio da análise dinâmica de programas [ISO/IEC/IEEE 2013]. Trata-se de uma análise dinâmica porque há a necessidade de
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