01. Universidade Federal Rural de Pernambuco - UFRPE (Sede)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/1
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Resultados da Pesquisa
Item Elaboração de um banco de imagens para a calibragem de um sistema semiautomático de contagem de ovos de Aedes aegypti(2022-05-27) Barbosa, Victor Araújo; Oliveira, Cláudia Maria Fontes de; Melo, Danielle Cristina Tenório Varjal de; http://lattes.cnpq.br/5037178667054052; http://lattes.cnpq.br/4031844994058757; http://lattes.cnpq.br/0644953966825218Entomological surveillance is an important strategy to know the occurrence of Aedes aegypti in the environment, and plan actions to control this mosquito. For this, one of the tools that can be adopted are the ovitraps, which are sensitive instruments for detecting A. aegypti in the environment, in addition to having a low cost and requiring little maintenance. However, counting the eggs obtained through these traps has been a laborious job, since each oviposition substrate can contain hundreds or thousands of eggs, which are manually counted with the aid of a magnifying glass by a trained professional. Operator fatigue and limited visualization of the substrate regions by the magnifying glass, as well as egg overlap, are factors that can lead to counting errors and make obtaining entomological data more time consuming. With that in mind, egg counting techniques from images have been studied, aiming to optimize the work, but still in an incipient way. Thus, this work sought to establish criteria for egg counting through image processing. For this, an image bank was created, with 40 specimens, of two types of oviposition substrates, one in wood (M) and another in fabric (T), having different densities of eggs. These substrates were submitted to manual counting and later their images were used for tests in digital processing. As a result, we observed better responses to processing on tissue substrates (T), with no statistical difference (p=0.1091) between manual and semi-automatic counting, whereas the results for the group (M) showed a statistical difference (0.00133 ) among the counting methods, verified through the Mann-Whitney statistical test. In addition, we were able to establish criteria for possible improvements in obtaining images that may favor processing. We therefore consider that establishing better conditions of focus, lighting and drying of the oviposition substrates to obtain the images can considerably improve the result for the two materials worked, requiring further tests.Item Atividade larvicida do extrato celular e de lectina extraídos de Chlorella vulgaris frente larvas em L4 de Aedes aegypti(2020-11-11) Silva, Maria Laura da; Bezerra, Raquel Pedrosa; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/0330489267196523Dengue, chikungunya and zika are viral diseases caused by the transmitting agent Aedes aegypti. According to data from the World Health Organization (WHO), the numbers of cases of these infections are increasing, the main method of prevention being the use of chemical insecticides to combat the vector, which has provoked resistance in the populations. The search for insecticides extracted from natural sources has been an alternative, thus, microalgae appear as a new possibility because they present biodegradable and non-toxic bioactives. Therefore, this research aimed to use the cell extract and Chlorella vulgaris lectin on A. aegypti to investigate larvicidal activity and inhibition on trypsin in the fourth larval stage (L4). The biomass of C. vulgaris was grown in Bold's Basal Medium. The biomass was concentrated and resuspended in a proportion of 10% w / v in 0.1 M Tris-HCl-NaCl buffer, pH 7.5 for the preparation of the cell extract by magnetic stirring for 9h and later performed hemagglutinating activity. Lectin was purified using anionic chromatography (DEAE-Sephadex) and Superdex 75 molecular exclusion. Cell extract at concentrations of 3.13% to 100%, and lectin from 25 to 200 μg mL-1, were applied to the larvae A. aegypti L4 during the 72-hour period following WHO recommendations. The cell extract showed an LC50 value with 3 hours (LC50 = 43.50%) and 24 hours (LC50 = 10.62%). While lectin showed LC50 at 24 hours (164.2 μg mL-¹), 48 hours (125.3 μg mL-¹) and 72 hours (106.5 μg mL-1). To observe the mechanism of action of intestinal trypsin, the LC50 of the cell extract containing 260 μg ml-1 of protein was applied to the fourth stage of A. aegypti larvae. Upon reaching the fourth stage, the larvae were incubated with the microalgae cell extract for a total period of 10 hours, and every 2 hours trypsin activity was performed. It was observed that the longer the cell extract treatment time with the larvae, the greater the reduction in intestinal extract trypsin activity. There was a 34.93% reduction in activity from the initial time with 2 hours to the final time with 10 hours. Thus, the present study using the cell extract, as well as the lectin isolated from C. vulgaris, appears as a new larvicidal potential of A. aegypti.Item Análise da atividade larvicida de hidrazidas contendo anéis do 1,2,4-oxadiazol e estudo das alterações morfo-histológicas em larvas de Aedes aegypti L. (Diptera, Culicidae)(2018-08-15) Nascimento, Jéssica da Silva; Oliveira, Lourinalda Luiza Dantas da Silva Selva de; Navarro, Daniela Maria do Amaral Ferraz; http://lattes.cnpq.br/6866049887225410; http://lattes.cnpq.br/7013867423178814The control of Aedes aegypti is now a major public health challenge because it’s responsible for important arboviruses such as: Dengue, Chikungunya, Zika and Urban Yellow Fever. In this work, we propose a study of the structure-activity relationship of 15 hydrazides against A. aegypti larvae, aiming to identify structural characteristics responsible for the larvicidal activity of the compounds. Fourth instar larvae were submitted to the compounds for 48 hours at different concentrations and then the LC50 was determined. Of the studied compounds, 9 presented considerable potential in the control of A. aegypti (LC50 <100ppm). The compound identied as HCBA presented greater larvicidal activity when compared to the others (LC50 = 20.63ppm) and aroused interest in understanding its mechanism of action. Larvae in the 4th instar were submitted to HCBA (20.63ppm), where they remained for 24 hours. The larvae that reached sublethal state were collected, xed in formoline, included in resin, sectioned, the blades stained by toluidine blue and analyzed by light microscopy. The morphohistological changes of the larvae submitted to the treatment were: high vacuolization in the cytoplasm and disorganization of the epithelium. These results demonstrate that the P-Cloro (HCBA) compound may be effective in controlling A. aegypti for promoting changes at the mesenteric level.