987 resultados para organic species


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A new species of eriophyoid mite, belonging in the genus Abacarus Keifer (Eriophyidae), causing damage to sugarcane, Saccharum officinarum L. (Poaceae), in Costa Rica is illustrated and described. Abacarus doctus n. sp. is the only eriophyoid species recorded so far with a tibial seta (l`) on the second pair of legs, an unexpected characteristic observed for the first time in the superfamily Eriophyoidea. Remarks on the phylogenetic and taxonomical aspects related to the presence of this seta are presented. Damage symptoms caused by this mite are presented as well as a key for Abacarus species described from sugarcane. In addition, the need to apply biosecurity procedures during sugarcane germplasm exchange to avoid dissemination of the new mite species is discussed.

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A new genus and two new species of eriophyoid mites in the family Diptilomiopidae associated with Spondias mombin L. (Anacardiaceae), namely Solivagus n. gen. alpha n. sp. and Davisella spondias n. sp., are described. In addition, a new species of Eriophyidae associated with Eugenia uniflora L. (Myrtaceae), namely Dichopelmus ibapitanga n. sp., is described and Aculus pitangae Boczek & Davis, also from E. uniflora, is redescribed including a description of the male, and its classification is discussed. All material studied was collected in the State of Pernambuco, Northeastern Brazil.

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In this paper we present the description of five new species of tetranychid mites collected in south Tunisian oasis areas. These are: Bryobia alveolata sp. nov., Aplonobia crispipilis sp. nov., Petrobia (Petrobia) carthagensis sp. nov., Petrobia (Petrobia) pseudotetranychina sp. nov. and Tetranychus (Tetranychus) atriplexi sp. nov. The notion of dorsal tubercles used to separate the sub-genera Tetranychina from Petrobia sensu stricto and Mesotetranychus among the genus Petrobia is also discussed.

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This work studied the radiation resistance of Listeria monocytogenes and Salmonella species and the effect of irradiation on leaf flavonoid content and sensory acceptability of minimally processed arugula. Immersion in ozone-treated water reduced the analyzed microorganisms by 1 log. L. monocytogenes and Salmonella were not isolated from samples. Samples of this vegetable were inoculated with a cocktail of Salmonella spp. and L. monocytogenes and exposed to gamma irradiation. D-10 values for Salmonella ranged from 0.16 to 0.19 kGy and for L. monocytogenes from 0.37 to 0.48 kGy. Kaempferol glycoside levels were 4 and ca. 3 times higher in samples exposed to 1 and 2 kGy, respectively, than in control samples. An increase in quercetin glycoside was also observed mainly in samples exposed to 1 kGy. In sensory evaluation, arugula had good acceptability, even after exposure to 2 and 4 kGy. These results indicate that irradiation has potential as a practical processing step to improve the safety of arugula.

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Microcystins (MC), a family of heptapeptide toxins produced by some genera of Cyanobacteria, have potent hepatotoxicity and tumor-promoting activity. Leukocyte infiltration in the liver was observed in MC-induced acute intoxication. Although the mechanisms of hepatotoxicity are still unclear, neutrophil infiltration in the liver may play an important role in triggering toxic injury and tumor development. The present study reports the effects of MC-LA, MC-YR and MC-LR (1 and 1000 nM) on human and rat neutrophils functions in vitro. Cell viability, DNA fragmentation, mitochondrial membrane depolarization and intracellular reactive oxygen species (ROS) levels were measured by flow cytometry. Extracellular ROS content was measured by lucigenin-amplified chemiluminescence, and cytokines were determined by ELISA. We found that these MC increased interleukin-8 (IL-8), cytokine-induced neutrophil chemoattractant-2 alpha beta (CINC-2 alpha beta) and extracellular ROS levels in human and rat neutrophils. Apart from neutrophil presence during the inflammatory process of MC-induced injury, our results suggest that hepatic neutrophil accumulation is further increased by MC-induced neutrophil-derived chemokine. (c) 2008 Elsevier Ltd. All rights reserved.

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The Kluyveromyces marxianus strains CBS 6556, CBS 397 and CBS 712(T) were cultivated on a defined medium with either glucose, lactose or sucrose as the sole carbon source, at 30 and 37A degrees C. The aim of this work was to evaluate the diversity within this species, in terms of the macroscopic physiology. The main properties evaluated were: intensity of the Crabtree effect, specific growth rate, biomass yield on substrate, metabolite excretion and protein secretion capacity, inferred by measuring extracellular inulinase activity. The strain Kluyveromyces lactis CBS 2359 was evaluated in parallel, since it is the best described Kluyveromyces yeast and thus can be used as a control for the experimental setup. K. marxianus CBS 6556 presented the highest specific growth rate (0.70 h(-1)) and the highest specific inulinase activity (1.65 U mg(-1) dry cell weight) among all strains investigated, when grown at 37A degrees C with sucrose as the sole carbon source. The lowest metabolite formation and highest biomass yield on substrate (0.59 g dry cell weight g sucrose(-1)) was achieved by K. marxianus CBS 712(T) at 37A degrees C. Taken together, the results show a systematic comparison of carbon and energy metabolism among three of the best known K. marxianus strains, in parallel to K. lactis CBS 2359.

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A partial pseudo-ternary phase diagram has been studied for the cethyltrimethylammonium bromide/isooctane:hexanol:butanol/potassium phosphate buffer system, where the two-phase diagram consisting of the reverse micelle phase (L-2) in equilibrium with the solvent is indicated. Based on these diagrams two-phase systems of reverse micelles were prepared with different compositions of the compounds and used for extraction and recovery of two enzymes, and the percentage of enzyme recovery yield monitored. The enzymes glucose-6-phosphate dehydrogenase (G6PD) and xylose redutase (XR) obtained from Candida guilliermondii yeast were used in the extraction procedures. The recovery yield data indicate that micelles having different composition give selective extraction of enzymes. The method can thus be used to optimize enzyme extraction processes. (c) 2007 Elsevier B.V. All rights reserved.

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Feijo, T.S., Cardozo, SX, Daleprane, J.B., Sabaa Srur, A.U.O. & Boaventura, G.T. [Evaluation of the influence of the proteinic quality of the genetically modified and organic soy beans in the growth of two generations of rats Wistar.] Avaliacao da influencia da qualidade proteica da soja geneticamente modificada e organica no crescimento de duas geracoes de ratos Wistar. Revista Brasileira de Medicina Veterinaria, 31(3):139-144, 2009. Programa de Pos-Graduacao em Patologia, Hospital Universitario Antonio Pedro. Centro de Ciencias Medicas, Universidade Federal Fluminense. Rua Marques do Parana, 303, Niteroi, RJ 24030-210, Brasil. E-mail: sergian@ufnj.br Sixty four Wistar rats, male of two consecutive generations determined as F(0) and F(1) were used to study the cumulative effect of two variety soy beans, cultivated with organic seasoning and genetically modified, The animals of each generation were divided into three groups of eight rats each fed on diets consisted of organic soy, soy genetically modified and casein respectively. All the animals received water and the diet ad libitum for period of 28 days. Where the diet consumption and the animals weight were evaluated. After statistic analysis of the results no expressive differences were observed on diet consumption, weight variation, protein efficient ratio and food efficiency ratio on same group of animals in the different generations. On the other hand, significant difference was found on final proteinic retention on animal descendants of the same groups; however of different generations. With this, the supplementation of organic soy with L-cistin provided better avail of this protein in relation to the protein of the soy genetically modified. However, this supplementation did not reveal efficiency in keeping the proteinic employment from one generation to another one, since soy varieties presented better performance on F(0) generation when compared with F(1).

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We have used two different probes with distinct detection properties, dichlorodihydrofluorescein diacetate and Amplex Red/horseradish peroxidase, as well as different respiratory substrates and electron transport chain inhibitors, to characterize the reactive oxygen species (ROS) generation by the respiratory chain in calcium-overloaded mitochondria. Regardless of the respiratory substrate, calcium stimulated the mitochondrial generation of ROS, which were released at both the mitochondrial-matrix side and the extramitochondrial space, in a way insensitive to the mitochondrial permeability transition pores inhibitor cyclosporine A. In glutamate/malate-energized mitochondria, inhibition at complex I or complex III (ubiquinone cycle) similarly modulated ROS generation at either mitochondrial-matrix side or extramitochondrial space; this also occurred when the backflow of electrons to complex I in succinate-energized mitochondria was inhibited. On the other hand, in succinate-energized mitochondria the modulation of ROS generation at mitochondrial-matrix side or extra-mitochondrial space depends on the site of complex III which was inhibited. These results allow a straight comparison between the effects of different respiratory substrates and electron transport chain inhibitors on ROS generation at either mitochondrial-matrix side or extra-mitochondrial space in calcium-overloaded mitochondria.

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We previously demonstrated that conidia from Aspergillus fumigatus incubated with menadione and paraquat increases activity and expression of cyanide-insensitive alternative oxidase (AOX). Here, we employed the RNA silencing technique in A. fumigatus using the vector pALB1/aoxAf in order to down-regulate the aox gene. Positive transformants for aox gene silencing of A. fumigatus were more susceptible both to an imposed in vitro oxidative stress condition and to macrophages killing, suggesting that AOX is required for the A. fumigatus pathogenicity, mainly for the survival of the fungus conidia during host infection and resistance to reactive oxygen species generated by macrophages.

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Disproportionation reactions take place in solution of (diacetoxyiodo)benzene (DIB) in acetonitrile in the presence of water, giving iodine(V) and iodine(l) species. This redox reaction is accelerated by the presence of water and by increasing the temperature. Several species of the solution of DIB were identified by high-resolution ESI-MS/MS, which allowed the elucidation of the mechanisms of disproportionation for DIB in gas phase and in solution. Key species in the process are the dimers [PhI(CH)OlPh](+) at m/z 440.8864, [PhI(OAc)OlPh](+) at m/z 482.8947, and [PhI(O)(OAc)OlPh](+) at m/z 498.8887. (C) 2008 Elsevier B.V. All rights reserved.

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Aiming at contributing with the search for neuroactive substances from natural sources, we report for the first time antinociceptive and anticonvulsant effects of some Lychnophora species. We verify the protective effects of polar extracts (600 mg/kg, intraperitoneally), and methanolic fractions of L. staavioides and L. rupestris (100 mg/kg, intraperitoneally) in pentylenetetrazole-induced seizures on mice. Previously, a screening was accomplished, evaluating the antinociceptive central activity (hot plate test), with different extracts of L. rupestris, L. staavioides and L. diamantinana. It was possible to select the possible extracts of Lychnophora with central nervous system activity. Some of the active extracts were submitted to fractionation and purification process and the methanolic fractions of L. rupestris (stem) and L. staavioides (stem), with anticonvulsant properties (100 mg/kg, intraperitoneally), yielded 4,5-di-O-[E]-caffeoylquinic acid. This substance was injected intraperitoneally in mice and showed anticonvulsant effect against pentylenetetrazole-induced seizures at doses of 25 and 50 mg/kg. It has often been shown that seizures induced by pentylenetetrazole are involved in inhibition and/or attenuation of GABAergic neurotransmission. However, other systems of the central nervous system such as adenosinergic and glutamatergic could be involved in the caffeoylquinic acid effects. Further studies should be conducted to verify that the target receptor could be participating in this anticonvulsant property. Although other investigations have reported a series of biological activities from Lychnophora species, this is the first report of central analgesic and anticonvulsant activity in species of this genus.

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In addition to adenosine triphosphate (ATP) production, mitochondria have been implicated in the regulation of several physiological responses in plants, such as programmed cell death (PCD) activation. Salicylic acid (SA) and reactive oxygen species (ROS) are essential signaling molecules involved in such physiological responses; however, the mechanisms by which they act remain unknown. In non-photosynthesizing tissues, mitochondria appear to serve as the main source of ROS generation. Evidence suggests that SA and ROS could regulate plant PCD through a synergistic mechanism that involves mitochondria. Herein, we isolate and characterize the mitochondria from non-photosynthesizing cell suspension cultures of Rubus fruticosus. Furthermore, we assess the primary site of ROS generation and the effects of SA on isolated organelles. Mitochondrial Complex III was found to be the major source of ROS generation in this model. In addition, we discovered that SA inhibits the electron transport chain by inactivating the semiquinone radical during the Q cycle. Computational analyses confirmed the experimental data, and a mechanism for this action is proposed.

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Foragers can improve search efficiency, and ultimately fitness, by using social information: cues and signals produced by other animals that indicate food location or quality. Social information use has been well studied in predator-prey systems, but its functioning within a trophic level remains poorly understood. Eavesdropping, use of signals by unintended recipients, is of particular interest because eavesdroppers may exert selective pressure on signaling systems. We provide the most complete study to date of eavesdropping between two competing social insect species by determining the glandular source and composition of a recruitment pheromone, and by examining reciprocal heterospecific responses to this signal. We tested eavesdropping between Trigona hyalinata and Trigona spinipes, two stingless bee species that compete for floral resources, exhibit a clear dominance hierarchy and recruit nestmates to high-quality food sources via pheromone trails. Gas chromatography-mass spectrometry of T. hyalinata recruitment pheromone revealed six carboxylic esters, the most common of which is octyl octanoate, the major component of T. spinipes recruitment pheromone. We demonstrate heterospecific detection of recruitment pheromones, which can influence heterospecific and conspecific scout orientation. Unexpectedly, the dominant T. hyalinata avoided T. spinipes pheromone in preference tests, while the subordinate T. spinipes showed neither attraction to nor avoidance of T. hyalinata pheromone. We suggest that stingless bees may seek to avoid conflict through their eavesdropping behavior, incorporating expected costs associated with a choice into the decision-making process.