RESUMO -Este trabalho teve como objetivo a avaliação das características anatômicas e fisiológicas de aguapé (Eichhornia crassipes) em resposta ao estresse por arsênio. As plantas de aguapé foram cultivadas em solução nutritiva hidropônica de Hoagland em casa de vegetação sob cinco concentrações de arsênio: 0,0; 0,25; 0,5; 1,0; e 2,0 mg L -1 por período de 20 dias. As plantas demonstraram aumento na taxa fotossintética, na condutância estomática, na transpiração e na relação Ci/Ca, bem como na atividade de todas as enzimas do sistema antioxidante, com maior atividade nas folhas em relação às raízes nos tratamentos contendo arsênio. As características anatômicas das folhas das plantas sob as maiores concentrações de arsênio mostraram aumento na densidade estomática, no índice estomático e na espessura do parênquima esponjoso. A anatomia radicular não evidenciou alterações decorrentes da intoxicação por arsênio e modificações nas características do xilema e floema, porém não houve prejuízos à sua estrutura e função. Dessa forma, o estresse por intoxicação pelo arsênio, nas concentrações testadas, não é evidente nas plantas de E. crassipes, e os mecanismos de tolerância são relacionados com modificações na anatomia e fisiologia das plantas.Palavras-chave: Eichhornia crassipes, anatomia ecológica, sistema antioxidante, fotossíntese.ABSTRACT -This work aimed to evaluate the anatomical and physiological characteristics of Eichhornia crassipes in response to arsenic stress. Plants of E. crassipes were grown in Hoagland hydroponic nutritive solution under greenhouse conditions at five arsenic levels: 0.0, 0.25, 0.50, 1.0 and 2.0 mg L -1 during 20 days. The plants showed an increase in photosynthetic rate, stomatal conductance, transpiration and Ci/Ca rate, as well as in the activity of all the enzymes in the antioxidant system, with higher activity in the leaves than in the roots, in all the treatments with arsenic. The anatomical characteristics observed on the leaves of the plants under higher arsenic levels showed an increase in stomatal density, stomatal index and spongy parenchyma thickness. Root anatomy showed no toxic evidences at any arsenic level; changes in the xylem and phloem characteristics were exhibited by the roots in the arsenic treatments, but no damage was caused to its structure and function. Thus, stress caused by arsenic intoxication at the levels tested, is not evident on E. crassipes plants, and the mechanisms of tolerance of E. crassipes are associated to anatomical and physiological changes.

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This study aimed at verifying the lead tolerance of water hyacinth and at looking at consequent anatomical and physiological modifications. Water hyacinth plants were grown on nutrient solutions with five different lead concentrations: 0.00, 0.50, 1.00, 2.00 and 4.00 mg L -1 by 20 days. Photosynthesis, transpiration, stomatal conductance and the Ci/Ca rate were measured at the end of 15 days of experiment. At the end of the experiment, the anatomical modifications in the roots and leaves, and the activity of antioxidant system enzymes, were evaluated. Photosynthetic and Ci/Ca rates were both increased under all lead treatments. Leaf anatomy did not exhibit any evidence of toxicity effects, but showed modifications of the stomata and in the thickness of the palisade and spongy parenchyma in the presence of lead. Likewise, root anatomy did not exhibit any toxicity effects, but the xylem and phloem exhibited favorable modifications as well as increased apoplastic barriers. All antioxidant system enzymes exhibited increased activity in the leaves, and some modifications in roots, in the presence of lead. It is likely, therefore, that water hyacinth tolerance to lead is related to anatomical and physiological modifications such as increased photosynthesis and enhanced anatomical capacity for CO 2 assimilation and water conductance.

The great majority of nosocomial fungal infections, especially fungemias, are caused by yeasts, mostly of the genus Candida. In addition, such infections may be associated with intravascular catheters. In this study, 80 yeast strains were isolated from hospitalized children, being 59 from blood cultures and 21 from vascular catheter cultures. The prevalent species in both blood and catheter was C. parapsilosis (32.2% and 48.9%, respectively), followed by C. albicans (16.9% and 28.6%, respectively). Concerning enzyme production, 78.8% of the 80 isolates presented strong proteolytic activity but 78.8% showed no phospholipase activity. We also detected two prevalent "killer" biotypes: 511 and 888. Additionally, in five patients, it was possible to observe that the yeast species, "killer" biotype and proteolytic and phospholipase activity of blood and catheter were similar. In view of this, we suggest a transmission of nosocomial yeast infection from catheter to blood.

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ABSTRACT. The aim of this study was to evaluate the antibacterial and antioxidant activities of essential oil from Chenopodium ambrosioides L. and to determine its secretory structures. The essential oil was extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC/MS and GC-FID. The antioxidant activity was determined by monitoring the reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and by the oxidation of the β-carotene/linoleic acid system. The evaluation of antibacterial activity was performed by the agar cavity diffusion technique using the microorganisms Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella Cholerasuis. The characterization of trichomes was accomplished by Scanning Electron Microscopy (SEM) and histochemical tests with Nadi and Sudan IV reagents. The antioxidant activity demonstrated by the β-carotene/acid linoleic test, with IC 50 = 455.7 μg mL -1 . This oil also presented antibacterial activity for both Gram-negative and Gram-positive bacteria. The minimal inhibitory concentration ranged 62.5 to 250 μL mL -1. The presence of terpenes in the glandular trichomes was observed, suggesting that the essential oil is secreted by these structures.Keywords: natural products, antioxidant assays, antimicrobial, trichomes.Óleo essencial de Chenopodium ambrosioides L.: estruturas secretoras, atividade antibacteriana e antioxidante RESUMO. Objetivou-se neste trabalho avaliar as atividades antibacteriana e antioxidante do óleo essencial de Chenopodium ambrosioides L. e determinar as suas estruturas secretoras. A extração do óleo essencial foi realizada pelo método de hidrodestilação, utilizando o aparelho de Clevenger modificado com duração de 2 horas, sendo, posteriormente, analisado por CG/EM e CG-DIC. A atividade antioxidante foi determinada monitorando-se a redução do radical livre DPPH (2,2-difenil-1-picril-hidrazila) e utilizando o ensaio de oxidação do sistema β-caroteno/ácido linoleico. A avaliação da atividade antibacteriana foi realizada por meio da técnica difusão cavidade em ágar, utilizando os micro-organismos Staphylococcus aureus, Listeria monocytogenes, Escherichia coli e Salmonella Cholerasuis. A caracterização dos tricomas foi realizada por Microscopia Eletrônica de Varredura (MEV) e pelos testes histoquímicos com os reagentes de Nadi e Sudan IV. A atividade antioxidante foi evidenciada pelo teste β-caroteno/ácido linoleico, com CI 50 455,7 μg mL -1. O óleo também apresentou atividade antibacteriana tanto para bactérias Gram-negativas como para Gram-positivas. A concentração mínima inibitória do mesmo variou entre 62,5 e 250 μL mL -1. Constatouse a presença de compostos terpênicos nos tricomas glandulares, inferindo-se que o óleo essencial seja secretado nessas estruturas.Palavras-chave: produtos naturais, ensaios antioxidantes, antimicrobiano, tricomas.

Oil palm cultivation has acquired economic importance due to rising demand for vegetable oils used in food, pharmaceutical, cosmetic and most recently, in biofuel industries. However, the commercial production increase of oil palm is limited by plantlet production, as it primarily uses seeds that require a long germination period and have low germination rates. In this study we evaluated the effect of embryo age (time after pollination), culture media and presence of carbohydrates on in vitro germination of zygotic embryos of oil palm (Elaeis guineensis Jacq.) Manicoré hybrid. Embryos at 80, 90, 100 and 110 days post-anthesis were inoculated in MS medium or modified Y3 medium, with or without 3% sucrose. Media were renewed after 30 days of inoculation, and plantlets were kept for 45 days until collection for histological analyses. The embryos did not germinate in medium without sucrose. Embryos of 100 days post-anthesis in MS medium showed the best result for germination rate (88%), which did not differ statistically from Y3 medium. As for the parameters, 90-day embryos showed better results for number and length of roots in Y3 medium. It was concluded that 90-day embryos cultivated in Y3 medium generate plantlets in better conditions to be transferred to acclimatization.

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