Efeito do estresse luminoso sobre Crotalaria spectabilis (Fabaceae) e seu inseto herbívoro, a mariposa Utetheisa ornatrix (Erebidae:Arctiinae)

The Plant Stress Hypothesis predicts that stressed plants are more attacked by herbivorous insects. In this work, we investigated the influence of light stress on Crotalaria spectabilis Roth (Fabaceae) and on its main herbivore, the moth Utetheisa ornatrix (L., 1758) (Erebidae: Arctiinae). Specifically, we verified whether plants stressed by shading differ from non-stressed plants in terms of productivity, morphological characteristics and water percentage. We also evaluated the performance of moths in stressed and non-stressed plants. Seeds were sown in pots. When the plants reached 50 cm in height, they were randomly divided into two groups: stressed plants (treatment group) and non-stressed plants (control group). The stressed plants were covered by a black mesh, providing 50% of shading. Eight characteristics of stressed and non-stressed C. spectabilis plants were evaluated: height, fresh and dry aerial biomass, number of pods and seeds, leaf hardness, number of trichomes, leaf area, specific leaf mass and percentage of leaf water. Moths were raised individually on leaves of stressed and non-stressed plants and we obtained the larval survival, larval development time, pupal weight and female fecundity. The non-stressed plants had significantly higher percentage of water in the leaves, greater fresh aerial biomass and a higher number of trichomes than the stressed plants. The survival rate was 98% for larvae raised on leaves from stressed plants and 92% on leaves from nonstressed plants. The larval developmental time was significantly shorter and the weight of female pupae significantly higher in non-stressed plants than in stressed plants. Thus, the Plant Stress Hypothesis was only corroborated by two tested variables: number of trichomes (lower in stressed plants) and larval survival (higher in stressed plants). Trichomes are among the main types of plant defenses against herbivory and reducing their number on leaves would make stressed plants more susceptible to attack by moth larvae, a fact corroborated by a greater larval survival. One of the possible explanations for the lack of corroboration of the Plant Stress Hypothesis for most of the variables tested is that other characteristics can be changed under stress conditions, such as the concentration of secondary compounds.A hipótese do estresse da planta prevê que as plantas estressadas são mais atacadas por insetos herbívoros. Neste trabalho, investigamos a influência do estresse luminoso em Crotalaria spectabilis Roth (Fabaceae) e em seu principal herbívoro, a mariposa Utetheisa ornatrix (L., 1758) (Erebidae: Arctiinae). Especificamente, verificamos se as plantas estressadas por sombreamento diferem das plantas não estressadas em termos de produtividade, características morfológicas e porcentagem de água. Também avaliamos o desempenho das mariposas em plantas estressadas e não estressadas. As sementes foram semeadas em vasos. Quando as plantas atingiram 50 cm de altura, foram divididas aleatoriamente em dois grupos: plantas estressadas (grupo de tratamento) e plantas sem estresse (grupo controle). As plantas estressadas foram cobertas por uma malha preta, proporcionando 50% de sombreamento. Foram avaliadas oito características de plantas estressadas e não estressadas de C. spectabilis: altura, biomassa aérea fresca e seca, número de vagens e sementes, dureza foliar, número de tricomas, área foliar, massa foliar específica e porcentagem de água foliar. As mariposas foram criadas individualmente em folhas de plantas estressadas e não estressadas. Obtivemos a sobrevivência larval, o tempo de desenvolvimento larval, o peso pupal e a fecundidade das fêmeas As plantas não estressadas apresentaram porcentagem significativamente maior de água nas folhas, maior biomassa aérea fresca e um maior número de tricomas do que as plantas estressadas. A taxa de sobrevivência foi de 98% para larvas criadas em folhas de plantas sob estresse e 92% em folhas de plantas sem estresse. O tempo de desenvolvimento larval foi significativamente menor e o peso das pupas femininas significativamente maior em plantas sem estresse do que em plantas estressadas. Assim, a hipótese de estresse em plantas foi corroborada apenas por duas variáveis testadas: número de tricomas (menor nas plantas estressadas) e sobrevivência larval (maior nas plantas estressadas). Os tricomas estão entre os principais tipos de defesa das plantas contra a herbivoria e a redução do seu número nas folhas tornaria as plantas estressadas mais suscetíveis ao ataque de larvas de mariposas, fato corroborado por uma maior sobrevivência larval. Uma das possíveis explicações para a falta de corroboração da hipótese de estresse de planta para a maioria das variáveis testadas é que outras características podem ser alteradas sob condições de estresse, como a concentração de compostos secundários

Poliol de ácido oléico como matéria prima para obtenção de poliuretanas

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Vertical Distribution of Leaves and Stems on the Sward and Forage Intake by Lambs in Tifton-85 Pasture

Sward characteristics affect the performance of grazing livestock, especially for the youngest animals. The aim of this study was to evaluate the relationship between the vertical distribution of leaves and stems on the sward and the forage intake parameters of lambs in four sheep meat production systems grazing a Bermudagrass (Cynodon dactylon) cv. Tifton-85 pasture

Performance of cryptococcal antigen lateral flow assay in serum, cerebrospinal fluid, whole blood, and urine in HIV-infected patients with culture-proven cryptococcal meningitis admitted at a Brazilian referral center

Cryptococcal meningitis is the most common cause of opportunistic meningitis in HIV-infected patients in Brazil and causes unacceptable high mortality rates. In this study, HIV-infected patients with a first episode of culture-proven cryptococcal meningitis in cerebrospinal fluid (CSF) were prospectively included in order to evaluate sensitivity of cryptococcal antigen (CrAg) lateral flow assay (LFA) in serum, CSF, whole blood (fingerstick), and fresh urine. In addition, HIV-infected patients with other neurological confirmed diseases were included in order to evaluate the specificity of CrAg LFA in serum. Twenty patients with cryptococcal meningitis were included and in 19 of them, CrAg LFA in CSF, serum, and whole blood were positive (95% sensitivity). In 18 patients, India ink test was positive in CSF (90% sensitivity), and in 16 cases, CrAg LFA was positive in urine (80% sensitivity). Thirty-six HIV-infected patients with other neurological diseases had negative results of CrAg LFA in serum (100% specificity). In conclusion, CrAg LFA in serum, CSF, and whole blood showed high sensitivity and specificity. Whole blood CrAg LFA seems to be a good and reliable strategy to improve AIDS-related cryptococcal meningitis diagnosis in Brazil

A triple-blinded crossover study to evaluate the short-term safety of sweet manioc starch for the treatment of glycogen storage disease type Ia

BACKGROUND: Glycogen storage disease type 1a (GSD Ia) is characterized by severe fasting hypoglycemia. The clinical management includes the administration of uncooked cornstarch (UCCS). Although such a diet approach is effective in achieving euglycemia, its impact on the quality of life of patients should be considered. In vitro analyses suggest a longer release of glucose when using sweet manioc starch (SMS). METHODS: We compared the efficacy and safety of the administration of SMS and UCCS during a short-fasting challenge in patients with GSD Ia in a randomized, triple-blind, phase I/II, cross-over study. GSD Ia patients aged ≥ 16 years and treated with UCCS were enrolled. Participants were hospitalized for two consecutive nights, receiving UCCS or SMS in each night. After the administration of the starches, glucose, lactate and insulin levels were measured in 1-h interval throughout the hospitalization period. The procedures were interrupted after 10 h of fasting or in a hypoglycemic episode ( 25 kg/m(2)) participated in the study. The average fasting period was 8.2 ± 2.0 h for SMS and 7.7 ± 2.3 h for UCCS (p = 0.04). SMS maintained euglycemia for a greater period over UCCS. Increased lactate concentrations were detected even in absence of hypoglycemia, not being influenced by the different starches investigated (p = 0.17). No significant difference was found in total cholesterol, HDL, triglycerides and uric acid levels in both arms. None of the patients showed severe adverse events. CONCLUSIONS: SMS appears to be non-inferior to UCCS in the maintenance of euglycemia, thus emerging as a promising alternative to the treatment of GSD Ia

Impacto da troponina I na avaliação de dor torácica aguda

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Estado e agricultores familiares: uma análise interpretativa sobre o desenvolvimento rural no Sul de Minas Gerais.

Este trabalho procurou identificar como os atores sociais vinculados à agricultura familiar (lideranças de produtores familiares, profissionais de ciências agrárias, autoridades municipais, pesquisadores e professores universitários) interpretam o papel do Estado para o desenvolvimento dessa categoria na região sul de Minas Gerais. Com relação à coleta de dados, utilizou-se a técnica "focused interview". Os entrevistados foram seledonados pelo método não-probabilístico de amostragem por julgamento. Os resultados revelaram que a interpretação feita pelos entrevistados aproxima-se mais da perspectiva do Estado patrimonialistaburocrático autoritário, tendo em vista que os depoimentos dos entrevistados corroboram com a reprodução das relações de dependência dos agricultores familiares em relação ao Estado. Por outro lado, alguns atores reconhecem a necessidade de mecanismos que incentivem a participação social, no entanto, salientaram que a mobilização dos produtores familiares na região ainda é incipiente e desarticulada