Comportamento alimentar, ritmo de atividade forrageadora e material capturado por Mischocyttarus cassununga Von Ihering, 1903 (Hymenoptera, Vespidae)

-Mischocyttarus cassununga é uma vespa eusocial de fundação independente, que possuí o ninho constituído por um único favo descoberto e preso ao substrato por um pedúnculo Apesar de ser uma espécie de ampla distribuição no ambiente urbano M. cassununga carece de mais estudos sobre sua biologia e ecologia comportamental. Este trabalho teve como objetivo analisar a atividade forrageadora de M. cassununga, correlacionando a atividade de busca de recursos com os fatores climáticos durante as fases de pré e pós-emergência nas diferentes estações do. O estudo foi conduzido no município de Juiz de Fora- MG entre os meses de Julho/2007 e Junho/2008. Foram realizadas 240 horas de observação, sendo 120 em 12 colônias de pré e 120 em 12 colônias de pós-emergência. Cada colônia foi observada por 10 horas (7 às 17h). E os indivíduos que saíam e retornavam do forrageio foram contabilizados. Ainda, foram registrados dados sobre a temperatura (°C), velocidade do vento (m/s), luminosidade (LUX) e umidade relativa do ar (%). Durante a estação fria e seca (julho/setembro e abril/ junho), tanto na pré quanto na pós-emergência verificou-se correlação siguinificativa entre número de saídas das forrageadoras e temperatura (r=0,6689; p<0,0001; r=0,6483; p<0,0001), umidade (r=-0,5203; p<0,0001; r=-0,4989; p<0.0001) e luminosidade (r=0,5940; p<0,0001; r=0,5219; p<0,0001), respectivamente. Já na estação quente e úmida (outubro/dezembro e janeiro/ março) houve correlação somente com a temperatura ( r = 0,4070 e p= 0,0013 e r = 0,3667 p=0,0039. Estes resultados revelaram que a espécie estudada apresentou padrões diferentes de forrageamento na estação quente e úmida se comparados ao descrito na literatura. Tal fato pode ser conseqüência das alterações climáticas durante as estações

Plants of Achillea millefolium L. grown under colored shading nets have altered secondary metabolism

Here we evaluate the effect of quality and quantity of light on growth and secondary metabolism of Achillea millefolium L. plants. Plants were cultivated under either full light or colored shading nets (blue, red or black). Analyzes were performed after eight weeks of shading and two and four weeks after the removal of the nets. Plants grown under nets presented lower dry weight of leaves and flowers. In addition, the synthesis of phenols and flavonoids decreased in leaves and flowers of shaded plants. On the other hand, the blue net increased the content of essential oil yield in leaves. The concentration of the majority of the compounds analyzed in the essential oil increased when using the black net. Farnesol and chamazulene were the most plenteous compounds in the oil of leaves and flowers in all conditions. Overall, these results indicate that different compounds respond differently to specific light lengths in A. millefolium plants. Thus, the photoselective treatments should be directed to the production of the target metabolite.(Plantas de Achillea millefolium L. crescidas sob sombreamento com malhas coloridas possuem alterações no metabolismo secundário). O efeito da qualidade e quantidade de luz no crescimento e metabolismo secundário foram avaliados em plantas de Achillea millefolium L.. As plantas foram cultivadas sob luz plena ou sob redes coloridas (azul, vermelho e preto) e avaliadas após oito semanas de sombreamento e após duas e quatro semanas da retirada das redes. Plantas sombreadas apresentaram menores valores de matéria seca de folhas e flores. Além disso, a síntese de fenóis e flavonóides diminuiu em folhas e flores de plantas sombreadas. Por outro lado, a rede azul aumentou o teor de óleo essencial nas folhas. A concentração da maioria dos compostos analisados no óleo essencial das plantas aumentou quando se utilizou a rede preta. Farnesol e chamazuleno foram os compostos mais abundantes no óleo essencial de folhas e flores em todas as condições. De forma geral, esses resultados demonstram como os compostos secundários respondem diferentemente à qualidade da luz em plantas de A. millefolium. Assim, os tratamentos fotosseletivos devem ser direcionados para a produção do metabólito de interesse

Quinolines: microwave-assisted synthesis and their antifungal, anticancer and radical scavenger properties

An efficient method for the synthesis of quinolines using microwave irradiation was developed providing 28 quinolines with good yields. The reaction procedures are environmentally friendly, convenient, mild and of easy work-up. Quinolines were evaluated for their antifungal, anticancer and antioxidant properties and exhibited high activities in all tests performed.Centro de Investigación y Desarrollo en Ciencias Aplicada

Toxicity of arsenic and role of nitric oxide in alleviating the damage caused in Spirodela intermedia W. Koch (Lemnaceae)

A toxicidade do arsênio (As) e seus efeitos no sistema antioxidante enzimático e não enzimático foram analisados em Spirodela intermedia. As plantas, cultivadas em solução nutritiva, pH 6,5, foram expostas a concentrações crescentes de As por 24 horas. Os objetivos deste estudo foram avaliar os efeitos de níveis tóxicos de As sobre a produção de espécies reativas de oxigênio (EROs), o sistema antioxidante enzimático e não enzimático e a morfologia externa das raízes. O acréscimo na concentração de As nas plantas desencadeou danos como aumento na produção de espécies reativas de oxigênio e peroxidação lipídica. Houve aumento linear do ânion superóxido, porém o peróxido de hidrogênio aumentou somente até a concentração de 1,0 mg L-1 de As. Também foi observado incremento no teor de antocianinas e na atividade das enzimas dismutase do superóxido (SOD), peroxidase (POX), peroxidase do ascorbato (APX), peroxidase da glutationa (GPX) e redutase da glutationa (GR). Em contraste, houve pequena queda na atividade da enzima catalase. Foi visualizado alterações micromorfológicas na coifa da raiz. Apesar da redução no teor de peróxido de hidrogênio nas concentrações mais elevadas, a atividade das enzimas antioxidantes não foi suficiente para amenizar os danos, uma vez que a concentração do ânion superóxido e de MDA aumentou linearmente com o acréscimo de As. As alterações micromorfológicas visualizadas na coifa da raiz, provavelmente foram decorrentes do aumento de EROs e consequente aumento da peroxidação lipídica. Em um segundo experimento, óxido nítrico (NO) foi suprido na forma de nitroprussiato de sódio (SNP). As plantas, cultivadas em solução nutritiva, pH 6,5, ½ força iônica, foram expostas a quatro tratamentos, sendo eles controle e As com e sem SNP, permanecendo nessas condições por 24 horas. Avaliou-se a influência do óxido nítrico (NO) sobre o dano de membrana e a atividade das enzimas antioxidativas e produtora de NO. Realizou-se também a detecção de fluorescência in situ desencadeada por NO. Houve aumento no teor de MDA, extravasamento de eletrólitos, enzimas antioxidativas e redutase do nitrato ao comparar o tratamento As (2,0 mg L-1) com As na presença de SNP. Sendo assim, considera-se que o efeito protetor da aplicação de SNP parece ser resultado da reação direta do NO com os EROs. Nas plantas submetidas ao estresse por As, observou-se maior produção de NO, resultado comprovado pela redutase do nitrato e pelo aumento na fluorescência. Quando fornecido na forma exógena, o NO também agiu diretamente na remoção de metabólitos tóxicos gerados em resposta ao As. Assim, verificou-se que o NO, fornecido pelo SNP, ameniza a toxicidade do As sobre o metabolismo de S. intermedia.The toxicity of arsenic (As) and its effects on antioxidant system were analyzed in S. intermedia. Plants treated in nutrient solution, pH 6.5, were exposed to increasing concentrations of As over a period of 24 hours. The objectives of this study were to evaluate the effects of toxic levels of As on production of reactive oxygen species (ROS), the antioxidative system and root external morphology. The increasing concentration of As was accompanied by higher production of reactive oxygen species and lipid peroxidation. There was a linear augmentation in the amount of superoxide anion and an increase in amount of hydrogen peroxide up to a concentration of 1.0 mg L-1 As. Augmentation in the amount of anthocyanins and higher activity of the enzymes superoxide dismutase (SOD), peroxidase ( POX), ascorbato peroxidase (APX), glutathione peroxidase (GPX) and glutathione reductase (GR) was also observed. In contrast, there was a slight decay in catalase activity. Despite the reduction in the concentration of hydrogen peroxide in higher concentrations of As, the activity of antioxidant enzymes was not enough to buffer the damage, since the concentration of superoxide anion and MDA increased linearly with the increase of As. In a second experiment, nitric oxide (NO) was supplied as sodium nitroprusside (SNP). Plants treated in nutrient solution, pH 6.5, ½ ion force, were subjected to four conditions: control (nutrient solution); SNP (15 mg L-1); As (2.0 mg L-1); As + SNP (2.0 and 15 mg L-1, respectively) over a period of 24 hours. It was evaluated the influence of nitric oxide (NO) on membrane damage and activity of antioxidant enzymes and NO production enzyme. In situ fluorescence detection was used to reveal NO presence. There was an increase in MDA content, membrane leakage, activity of antioxidative enzymes and nitrate reductase comparing 2.0 mg L-1 As conditions with As + SNP treatment. Therefore, it is considered that the protective effect of the application of SNP appears reflects direct reaction of NO with ROS. The plants under arsenic stress showed higher NO production, confirmed by the increase in nitrate reductase activity and augmentation in fluorescence levels. When provided exogenously, NO also acted directly in the removal of toxic metabolites generated in response to As. Therefore, it was found that NO, supplied by SNP, buffers As toxicity in S. intermedia.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Salinity-induced accumulation of endogenous H2S and NO is associated with modulation of the antioxidant and redox defense systems in Nicotiana tabacum L. cv. Havana

Salinity is one of the abiotic factors that most affect crop growth and production. This study focused on the effect of high salinity on the endogenous levels of the signaling molecules hydrogen sulfite (H2S) and nitric oxide (NO) in Nicotiana tabacum leaves and the extent of these for the biochemically-driven plant tolerance to such abiotic stress. The NaCl treatment for 10 days led to an expressive augment of H2S and NO levels. This increase was correlated with the raise of l-Cys and l-Arg and the induction of l-cysteine desulfhydrase, cyanoalanine synthase, cysteine synthase, nitrate reductase and arginase, enzymes known to be involved in the biosynthesis of H2S or NO. The enzymatic antioxidant system (superoxide dismutase and catalase activity) was boosted and the non-enzymatic antioxidant glutathione was intensively oxidized in leaves upon stress allowing plants to cope with oxidative stress. Lower stomatal conductance was observed in stressed plants in comparison with control ones. Moreover, the high activity of antioxidant enzymes and high rate of glutathione oxidation following salt stress were considerably decreased upon NO or H2S scavenging. Thus, increment in NO and H2S levels and their interplay, along with metabolic and physiological changes, contributed to tobacco survival to extreme salinity conditions

Assimilação de carbono em plantas de soja coinoculadas com azospirillum e submetidas ao alagamento e elevado CO2

O objetivo do trabalho foi avaliar a assimilação de carbono e o crescimento de plantas de soja quando coinoculadas com Azospirillum e cultivadas em ambientes alagados sob alto nível de CO2

Environmental factors on seed germination, seedling survival and initial growth of sacha inchi (Plukenetia volubilis L.)

Abstract: Sacha inchi (Plukenetia volubilis L.) is an Amazon species of elevated agro-industrial potential due the high content of omega-3 and omega-6 in its seeds. Despite of it, little information about its propagation by seeds is currently available. Thus, the aim of this study was to assess seed germination, seedling survival and growth of this species under different conditions of substrate (on paper, between papers and paper roll), light (continuous darkness, 12-h photoperiod and continuous light) and temperature (continuous temperature at 20, 25, 30, 35 and 40 °C). Germination is stimulated by substrates with increased surface contact with the seeds, presence of light and temperatures between 25 and 35 °C. Survival and initial growth of seedlings are favored by vermiculite, continuous light and 30 °C temperature. These conditions allow rapid and uniform germination of seeds and better establishment and development of seedlings. We encourage the propagation of sacha inchi by seeds, since we consider it a feasible technique

Root-hypoxia tolerance in soybean sister-lines plants indicates a better balance in energy use/dissipation and oxidative stress control

Climatic changes are leading to an increased number of flooding year by year which impacts negatively the metabolism of roots and influences the shoot metabolism which leads to a decline in soybean productivity. This can be more drastic when it is cultivated in lowland soils. Our group hypothesized that tolerant sister-line plants have more capacity to cope with oxidative stress due to better management of energy use and dissipation on photosynthesis machinery during root-flooding and recovery conditions, while in sensitive soybean sister-line the impairment of the photosynthetic use and dissipation of energy lead to an unbalanced redox state response. For that, soybean seeds from the same parents, PELBR15- 7015C (flooding tolerant) and PELBR15-7060 (flooding sensitive) were sowed and cultivated in 500 L capacity plastic containers with lowland soil simulating the field management process. At the reproductive stage, the roots were subjected to flooding for 11 days, then drained to analyze reoxygenation (3 d) and recovery (10 d). Tolerant plants have a greater ability to manage root flooding conditions compared to sensitive ones. The ability includes efficient energy use and dissipation, which minimizes the production of reactive oxygen species (ROS) and subsequent cell damage. Conversely, in sensitive sister lines, impaired electron transport chains lead to increased ROS production and damage. Upon reoxygenation and recovery, the tolerant sister lines exhibit a faster metabolism turnover, allowing them to cope more effectively with the stress on leaves and roots. While both sister lines are capable of detoxifying ROS, the tolerant sister line's superior ability to manage energy use and dissipation allows for more stable and rapid control of oxidative stress

An efficient system for in vitro propagation of Bouchea fluminensis (Vell.) Mold. (Verbenaceae)

This study aimed to establish and propagate in vitro plants of Bouchea fluminensis, a medicinal species known in Brazil as gervão-falso ("false verbena"), evaluating the influences of different growth regulators on in vitro multiplication and rooting stages, as well as examining ex vitro acclimatization of rooted plants. Explants were established on Murashige and Skoog medium at half strength of salts and vitamins without growth regulators. For multiplication, the explants were subjected to combinations of 6-benzyladenine (BA; 0, 2.5, 5.0 and 7.5 µM) and α-naphthalene-acetic acid (NAA; 0, 0.2, 0.4 and 0.6 µM). The medium found to induce the greatest number of shoot was that containing 5 µM of BA (NAA-free). For rooting, we evaluated three auxins (NAA, indole-3-acetic acid and indole-3-butyric acid; 0.1, 0.2, 0.3 and 0.4 µM), as well as a control. No differences were observed between the control and the other treatments. The auxin-free medium was deemed the most suitable, because it ensures the lowest cost in the micropropagation procedures. We obtained 100% survival of the acclimatized seedlings, and the plants showed normal vegetative and reproductive development, suggesting that the micropropagation did not alter the biological cycle of this species. The results show the importance and potential of micropropagation for biodiversity conservation of Bouchea fluminensis