EVZ - Escola de Veterinária e Zootecnia
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Item Caracterização química e biológica de feromônios de Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)(Universidade Federal de Goiás, 2010-08-13) GACHOKA, Kennedy Kiriira; FERRI, Pedro Henrique; http://lattes.cnpq.br/2129799749473005; SILVA, Andrea Caetano da; http://lattes.cnpq.br/1432918585717355; BORGES, Lígia Miranda Ferreira; http://lattes.cnpq.br/2591106734434348Amblyomma cajennense, commonly known as Cayenne tick, is a three-host tick widely distributed in Brazil and in the rest of Latin American countries. Owing to its low host specificity, it plays an important role in the transmission of pathogens in animals and man. Chemical communication is a vital component in tick biology whereby pheromones are largely responsible in the regulation of mating, recognition of sexual partner and copulation. By understanding the behaviour of A. cajennense and the pheromones involved, there exists practical possibility for the use of these substances as an additional method of control thereby reducing the use of acaricides. Based on this, the aims of this work were to quantify and elucidate behaviours induced by pheromones emitted by females A. cajennense as well as identify and characterize qualitatively and biologically the pheromone produced by males. Engorged females were collected from naturally-infested horses for the establishment of laboratory colonies for use in this study. The pheromones were obtained by extraction in hexane and sonication by ultra-sound of fed males and females. The female sex pheromone, 2,6-dichlorophenol (2,6-DCP), was quantified by GC/MS using internal standard and standard addition methods through construction of calibration curves using 5-bromine-4-hydroxy-3-methoxybenzaldehyde and 2,6-DCP, respectively. The male extract was analysed chemically by GC/MS in comparison with standards. As concerns biological tests, glass beads were treated with two femaleequivalents of the female pheromone and 2,6-DCP in an equivalent concentration and exposed to males to observe the induced behaviour(s). Attraction to the male pheromone was evaluated by release of individual unfed, virgin females to three concentrations (1, 5 and 10 male-equivalents) of the extract in olfactometer bioassays. Orientations towards the odour source were analysed by Kruskal-Wallis and displacement angles by Circular Statistics. Aggregation was evaluated by releasing the tick stages in Petri dish bioassays shortly followed by introduction of filter paper strips impregnated with 10 male-equivalents of the extract and recording tick responses on camera. Data analysis was by Chi-square test. Tests for attachment were carried out in vivo in rabbits, Oryctolagus cuniculus, and the released ticks observed in determined intervals between 20min and 24hrs. The data was analysed by Wilcoxon signed-ranked test and Friedman s repeated measures ANOVA. The results indicated that each female emits 2.15 ng ml-1 of pheromone on average. The male extract was positive for benzoic acid, nonanoic acid, salicylic acid, benzaldehyde, 2,6-DCP, limonene and methyl salicylate. The female extract and 2,6- DCP stimulated mounting in up to 80% and 73% of all cases, respectively, confirming that 2,6-DCP alone mediates mounting behaviour in A. cajennense. There was no statistically significant attraction or aggregation in males or females induced by the male pheromone. However, significantly faster and greater attachment was recorded in both. The behavioural responses corresponded with the pheromone s composition. It was concluded that the male pheromone promotes neither attraction nor aggregation but is responsible for faster fixation of A. cajennense adults. The pheromone also contains different proportions and differs from other Amblyomma species as far as the presence or absence of certain components is concerned. The results serve as a first step in advanced studies aimed at development of novel strategies for the management of this species using these pheromones.Item ASPECTOS DA ECOLOGIA QUÍMICA DE Rhipicephalus sanguineus (Latreille, 1806) (ACARI: IXODIDAE) EM DUAS RAÇAS DE CÃES(Universidade Federal de Goiás, 2008-08-15) LOULY, Carla Cristina Braz; BORGES, Lígia Miranda Ferreira; http://lattes.cnpq.br/2591106734434348This study aimed to identify 2,6-dichlorophenol (2,6-DCP) in Amblyomma cajennense and to evaluate its role in A. cajennense and Rhipicephalus sanguineus courtship. Hexanic extract from attractive females was purified by solid phase extraction and the phenol was identified by the single ion monitoring method using GC/MS. In an olfactometer, the responses of A. cajennense and R. sanguineus males to females, control rubber septa or rubber septa impregnated with 2,6-DCP at 50, 500, and 5000 ng, respectively, were studied. 2,6-DCP was identified in A. cajennense extract and the males oriented themselves toward the concentration of 500 ng. These septa and the females were recognized as copula partners. The septa treated with 2,6-DCP did not attract and were not even recognized by the R. sanguineus males, whereas the females were recognized. Due to the presence of 2,6-DCP in A. cajennense and the results of biological bioassays, it was concluded that this compound acts as an attractant and mounting sex pheromone in this tick, but it does not play any role in R. sanguineus courtship.Item Efeitos toxicológicos agudos de extratos de Melia azedarach (MELIACEAE) em ratos (Rattus novergicus), camundongos (Mus musculus) e Artemia salina(Universidade Federal de Goiás, 2010-02-24) PIRES JÚNIOR, Hélio Bernardes; CUNHA, Luiz Carlos da; http://lattes.cnpq.br/6349547031976679; SILVA, Andrea Caetano da; http://lattes.cnpq.br/1432918585717355; BORGES, Lígia Miranda Ferreira; http://lattes.cnpq.br/2591106734434348The revival of research involving botanical insecticides owes itself to the need to make available new products devoid of environmental degradation, with lesser residual affects and development of resistant insects to synthetic products. Phytochemicals from the family Meliaceae have been considered preeminent pesticides. Among the Maliaceae, one of the plants that stands out is Melia azedarach. Diverse studies report the effects of this plant on insects of importance in public health, agriculture and livestock sectors. In spite of M. azedarach being considered a medicinal plant, its use as a natural insecticide needs to be cautious because the plant contains various toxic components to mammals. The objective of this work was to verify the toxicity of extract from unripe fruits of M. azedarach against Wistar rats, Swiss mice and Artemia salina, as well as dermal and ocular irritation in rabbits. Unripe fruits were harvested and processed at the Chemistry Department of UFG. For the acute toxicity test, fruit extracts were administered by gavage at doses of 300 and 2000 mg/kg, in rats and mice of both sexes. For evaluation, animals were observed both for the presence of clinical signs or their death for 14 days after the administration, afterwards all the animals underwent euthanasia and their organs collected for use in histopathology analysis. Data on ration and water consumption, weight gain and weight of the organs were also analysed. Dermal and ocular irritation was evaluated on rabbits using a crude extract on the skin and on the conjunctive sac. The bioassay with A. salina involved eight repeats in the following dilutions, 125, 250, 500 and 1000 μg/ml and an untreated control. The dishes containing the groups were incubated in the dark at 25 ºC and readings taken after 24 hours, by counting the number of surviving individuals. The acute toxicity results obtained demonstrated that the M. azedarach extract did not induce mortality or clinical alteration, just as there was no change in weight gain, ration consumption and organs weight when the treatments and controls were compared. From histopathology analyses, some alterations were detected especially in the liver and lungs, however these lesions were common to the treatments and controls. The assay done in rabbits demonstrated that the extract was not irritative to the skin and eye. The LC50 of the M. azedarach extract was 669 ug/ml, as obtained from the A. salina assay, the extract being considered moderately toxic to this microcrustacean. In spite of these results to have produced evidence that this plant s extract is safe to mammals, further studies such as modes of action of this plant, sub-acute and chronic toxicity assays, effects on specific organisms and on the environment, are necessary towards the definition of this plant as being of low risk to the environment, domestic animals and to man.