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 Investigação do extrato de cladódios de Cereus jamacaru quanto à composição química, potencial antimicrobiano contra Staphylococcus aureus e efeito larvicida para Aedes aegypti(2023-09-21) Guimarães, Júlia Maria Rodrigues; Pontual, Emmanuel Viana; Alves, João Victor de Oliveira; http://lattes.cnpq.br/0882174483226946; http://lattes.cnpq.br/1777060469196142; http://lattes.cnpq.br/3701748857935689Cereus jamacaru (Cactaceae), mandacaru, is a plant from the Brazilian semi-arid region that has economic importance for livestock farming and use in folk medicine. The use of currently commercialized antibiotics leads to many unwanted effects and has led to the emergence of resistant bacteria, while synthetic insecticides generally have high persistence in the environment and strong non-target toxicity. In this sense, the search for new antimicrobial agents and insecticides has grown. The aim of this work was to investigate the cladode extract of C. jamacaru regarding its chemical composition (presence of lectins, protease inhibitors and secondary metabolites), antimicrobial potential against pathogenic bacteria and larvicidal effect against Aedes aegypti. Cladodes of C. jamacaru were collected in Recife, Pernambuco. The spines were removed and the cladodes were cut into slices and air-dried (28°C, 4 days). Then, the cladodes were crushed and the powder (10 g) was homogenized (28°C, 16 h) with 0.15 M NaCl solution (100 mL) in water, using a magnetic stirrer. The mixture was filtered and centrifuged (3,000 g, 15 min) and the clear supernatant corresponded to cladode extract (CjCE) which was investigated for the presence of lectins using rabbit erythrocytes, protease inhibitor using bovine trypsin (0.1 mg/ mL) and the chromogenic and peptidomimetic substrate BApNA (8 mM), and secondary metabolites by thin layer chromatography. The content of phenolic compounds in CjCE was determined using the Folin-Ciocalteu reagent (10%, v/v) and a gallic acid standard curve, while flavonoids were quantified using the aluminum chloride reagent (20%, m/v) and quercetin as standard. Then, the extract was investigated for antioxidant activity using the DPPH, ABTS and Phosphomolybdenum methods. The antibacterial potential of CjCE was determined using bacterial strains sensitive or resistant to antibiotics by the plate microdilution method. The minimum inhibitory concentration (MIC, lowest concentration of CjCE capable of inhibiting bacterial growth by 50%) was determined. Hemolysis assay by S. aureus was performed using human erythrocytes and the effect of CjCE (128, 64 and 32 µg/mL) on hemolysis was investigated. The larvicidal potential of CjCE (0.40 to 3.5%, m/v) was evaluated by treatment (48 h) of A. aegypti larvae in the third instar (L3). CjCE caused agglutination of rabbit erythrocytes (8 UAH), suggesting the presence of lectins. The extract reduced the hydrolysis of the BApNA substrate by trypsin, indicating the presence of a protease inhibitor. CjCE thin layer chromatography revealed the presence of reducing sugars and qualitative-quantitative analysis showed 40.20±0.97 mgEAG/g of total phenols, among which, 3.36±0.07 mgEAG/g (8, 36%) were flavonoids. CjCE showed relevant oxidant activity, with the ability to scavenge ABTS and DPPH radicals (IC50 of 3,735 µg/mL and 2704.50 µg/mL, respectively), but was not able to cause reduction of phosphomolybdenum. CjCE was toxic only to the Staphylococcus aureus strain (UFPEDA 02), revealing a strong bacteriostatic effect (MIC of 199.09±0.85 µg/mL), and reduced erythrocyte lysis caused by the bacteria by more than 90%, compared to to control. The treatment of L3 of Ae. aegypti with CjCE resulted in dose-dependent mortality (LC50 = 0.68%, m/v). On the other hand, when larvae were treated with CjCE at a concentration 10 times higher than the LC50, the intestinal contents covered by the peritrophic membrane were eliminated in an attempt to eliminate the toxic components of the extract. In conclusion, C. jamacaru cladode extract is a novel antimicrobial agent capable of strongly inhibiting the growth of S. aureus and reducing bacterial toxicity to human erythrocytes. Furthermore, the toxicity to A. aegypti larvae shown here points to the C. jamacaru cladode extract as an interesting starting material for obtaining larvicidal formulations. The antibacterial and insecticidal effects of the extract may be linked to the presence of lectins, protease inhibitors and phenolic compounds.Item Avaliação da variabilidade genética de mosquitos das espécies Aedes aegypti e Culex quinquefasciatus, provenientes de pontos estratégicos da Região Metropolitana do Recife(2022-10-07) Matos, Rafaela Cassiano; Souza Júnior, José Dijair Antonino de; http://lattes.cnpq.br/9268515833435844; http://lattes.cnpq.br/0333341555119539Invasive species such as Aedes (Ae.) and Culex (Cx.) mosquitoes play a relevant role due to their association with the transmission of several arboviruses such as Dengue, Chikungunya and Zika viruses. The complexity in controlling these mosquitoes becomes a challenge when we consider the effects of globalization, the changes climate change and the disorderly processof urbanization in urban centers. Alternative control methods have been developed and implemented to control dispersion and transmission of pathogens by these vectors. Nonetheless,despite all efforts, epidemics show constants. With this, knowing more about the biology of thevector can help in the creation of more effective strategies of control, in order to reduce the populations of these Culicidae and consequently the transmission of arboviruses. That said, in order to evaluate mosquitoes collected at points of entrance of the Metropolitan Region of Recife, this work analyzed the genetic variability of the species Aedes aegypti and Culex quinquefasciatus in four locations, Porto do Recife, Terminal Integrado de Passageiros, Porto de Suape and the Centro de Abastecimento e Logística de Pernambuco. Eggs and immature forms of these Culicidae were collected and later taken to the insectary of the Department of Entomology at IAM, where they completed their development cycle for collection of adults. Females from these populations underwent DNA extraction, followed by PCR amplification ofthe mitochondrial genes Cytochrome C Oxidase subunit I (COI) and NADH subunit 4 (ND4), sequenced and analyzed. The analysis performed for the COI gene revealed low nucleotide diversity ([pi]=0.00174; 0.00016) for both species. As for the ND4 gene, the nucleotide diversitywas (pi) 0.01086 and 0.0000, for the populations of A. aegypti and Cx. quinquefasciatus, respectively. The analysis of the COI and ND4 gene for A. aegypti populations revealed the presence of 5 and 34 haplotypes, respectively, with the H1 and H3 haplotypes being the most frequent, present in 91.48% and 56%. Analysis of the COI and ND4 gene for Cx. quinquefasciatus populations. revealed the presence of four and one haplotype, respectively, with the H1 haplotype being the most frequent for the COI gene, present in 96.04% of the individuals. In view of the results obtained, it was observed that the species A. aegypti is more diverse than the species Cx. quinquefasciatus, in addition, the TIP locality has the highest rates of nucleotide diversity for both species, which may be linked to the multiple introductions of these Culicidae that are promoted by the constant flow of people and transport of different types.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.Item Relatório de Estágio Supervisionado Obrigatório - Laboratório de Aquicultura e Sustentabilidade(2022-05-27) Ramos, Gabriela de Albuquerque; Porto Neto, Fernando de Figueiredo; http://lattes.cnpq.br/1475750525654086; http://lattes.cnpq.br/5708959546281094