73 resultados para TOXIC CYANOBACTERIA

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Water quality of a fish pond used by UNESP, at Jaboticabal, SP, Brazil, for both fishing and irrigation has been evaluated according to certain limnological parameters and to its phytoplankton composition. During the year, four sampling sites were assigned at the pond: P(1)=inlet water in the pond; P(2)=inlet water from a shrimp pond; P(3)=irrigation spot; and P(4)=outlet water (water flowing directly into another pond). The collected data show a water pond with high concentration of nutrients and chlorophyll-a, and high values of electrical conductivity, total hardness and total dissolved solids, proceeding from the above pond. These factors affected substantially some biological parameters, such as chlorophyll-a and phytoplankton. In P(3), whereas class Zygnematophyceae showed the highest specimens richness, with 34.01%, the Chlorophyceae, that had the highest number of genera, comprehended 33.52% of the total number of individuals. The use of the water fish pond for irrigation must be re-evaluated, due to eutrophic conditions of the water, the presence of potentially toxic cyanobacteria, so as the proper management employed.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

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Algae bloom is one of the major consequences of the eutrophication of aquatic systems, including algae capable of producing toxic substances. Among these are several species of cyanobacteria, also known as blue-green algae, that have the capacity to adapt themselves to changes in the water column. Thus, the horizontal distribution of cyanobacteria harmful algae blooms (CHABs) is essential, not only to the environment, but also for public health. The use of remote sensing techniques for mapping CHABs has been explored by means of bio-optical modeling of phycocyanin (PC), a unique inland waters cyanobacteria pigment. However, due to the small number of sensors with a spectral band of the PC absorption feature, it is difficult to develop semi-analytical models. This study evaluated the use of an empirical model to identify CHABs using TM and ETM+ sensors aboard Landsat 5 and 7 satellites. Five images were acquired for applying the model. Besides the images, data was also collected in the Guarapiranga Reservoir, in São Paulo Metropolitan Region, regarding the cyanobacteria cell count (cells/mL), which was used as an indicator of CHABs biomass. When model values were analyzed excluding calibration factors for temperate lakes, they showed a medium correlation (R²=0.81, p=0.036), while when the factors were included the model showed a high correlation (R²=0.96, p=0.003) to the cyanobacteria cell count. The empirical model analyzed proved useful as an important tool for policy makers, since it provided information regarding the horizontal distribution of CHABs which could not be acquired from traditional monitoring techniques.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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1 Nine synthetic amides similar to natural N-piperidine-3-(4,5-methylenedioxyphenyl)-2-(E)-propenainide and N-pyrrolidine-3-(4,5-methylenedyoxiphenyl)2-(E)-propenamide were synthesized and identified by their spectroscopic data.2 the toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leticoagaricus gongylophorus, the symbiotic fungus of the leaf-cutting ants, were determined.3 Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N-pyrrolidine-3(3',4'-methylenedioxyphenyl)-2-(E)-propenamide and N-benzyl-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mu g/mL.4 the completely inhibition (100%) of the fungal growth was observed with N-piperldine-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide and N,N-diethyl-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at concentrations of 50 and 100 mu g/mL and N-pirrolidine-3-(3',4'-methylenedioxyphenyl)-2-(E)-propenamide at a concentration of 100 mu g/mL.5 the possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.

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Studies assessing the characteristics of active ingredients (AIs) of toxic baits for leaf-cutting ants are still scarce, although the need for a delayed action of these compounds on adult workers has been well accepted (mortality <= 15% at 24 h and <= 90% at 21 days). Therefore, we determined the insecticidal action of two AIs used in commercial baits, diflubenzuron and dechlorane, over time in workers, and discussed the control of colonies in relation to the existing literature. Dechlorane presented excellent insecticidal activity with a delayed action at all concentrations tested, although its commercial use has been prohibited due to its organochlorine nature. In contrast, diflubenzuron did not cause significant mortality or symptoms of intoxication, indicating that the successful cases reported with the use of baits containing this AI were in fact due to an accidental contamination with dechlorane. We comment about the ineffectiveness of diflubenzuron on alternative targets, i.e., young forms and the mutualistic fungus, supporting the concept that the AI needs to a have a delayed action on adult workers.

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This work reports the chemical characterization of Eremanthusgoyzensis essential oil and its toxic effect over Brevipalpus phoenicis. The essential oil displayed a major composition of sesquiterpenes (61.87%) including trans-caryophillene (26.81%) and germacrene-D (13.31%). The fumigation test indicated a promising bioactivity over adult B. phoenicis individuals at 24 h (2.03 µL/L of air) and 48 h (1.08 µL/L of air) of exposition. A brief discussion of essential oils composition and their singular role on the toxic effect over B. phoenicis is provided here. Our results may contribute to a new and profitable use of a species of Brazilian flora on agribusiness.

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This pilot study uses concentrations of metals in maternal and cord blood at delivery, in seven selected geographical areas of South Africa, to determine prenatal environmental exposure to toxic metals. Samples of maternal and cord whole blood were analysed for levels of cadmium, mercury, lead, manganese, cobalt, copper, zinc, arsenic and selenium. Levels of some measured metals differed by site, indicating different environmental pollution levels in the regions selected for the study. Mercury levels were elevated in two coastal populations studied (Atlantic and Indian Ocean sites) with mothers from the Atlantic site having the highest median concentration of 1.78 mu g/L ranging from 0.44 to 8.82 mu g/L, which was found to be highly significant (p < 0.001) when compared to other sites, except the Indian Ocean site. The highest concentration of cadmium was measured in maternal blood from the Atlantic site with a median value of 0.25 mu g/L (range 0.05-0.89 mu g/L), and statistical significance of p < 0.032, when compared to all other sites studied, and p < 0.001 and p < 0.004 when compared to rural and industrial sites respectively, confounding factor for elevated cadmium levels was found to be cigarette smoking. Levels of lead were highest in the urban site, with a median value of 32.9 mu g/L (range 16-81.5 mu g/L), and statistically significant when compared with other sites (p < 0.003). Levels of selenium were highest in the Atlantic site reaching statistical significance (p < 0.001). All analysed metals were detected in umbilical cord blood samples and differed between sites, with mercury being highest in the Atlantic site (p < 0.001), lead being highest in the urban site (p < 0.004) and selenium in the Atlantic site (p < 0.001). To the best of our knowledge this pilot investigation is the first study performed in South Africa that measured multiple metals in delivering mothers and umbilical cord blood samples. These results will inform the selection of the geographical sites requiring further investigation in the main study.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A prostaglandina F2a pode ser usada em caes para aumentar o volume do ejaculado em casos de inseminação artificial, criopreservação seminal ou biotecnologias de reprodução. Os efeitos colaterais após a administração da PGF2a, como taquicardia, salivação, emese, diarréia e convulsões geralmente são relacionadas com a dose utilizada. Esse trabalho objetiva relatar a ocorrência de hepatite tóxica aguda após a administração de PGF2a em um cão, e discutir a importância de se utilizar essa droga com cautela nessa espécie.