Controle biológico de Echinostoma Paraensei pelo fungo nematófago Pochonia chlamydosporia

• Ano de defesa: 2014
• Autor(a) principal: Lelis, Rosane Teixeira
• Orientador(a): Araújo, Jackson Victor de
• Banca de defesa: Oliveira, Leandro Licursi de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Medicina Veterinária
• Departamento: Biotecnologia, diagnóstico e controle de doenças; Epidemiologia e controle de qualidade de prod. de
• País: BR
• Palavras-chave em Português: Controle biológico; Fungos nematófagos; Pochonia Chlamydosporia; Echinostoma Paraensei
• Palavras-chave em Inglês: Biological control; Fungi Nematophagous; Pochonia chlamydosporia; Echinostoma Paraensei
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA
• Link de acesso: http://locus.ufv.br/handle/123456789/5182

Echinostoma paraensei is a trematode of the genus Echinostoma that can cause echinostomiasis in humans. The aims of this study were to evaluate the ovicidal activity of the isolates VC1 and VC4 of the nematophagous fungus Pochonia chlamydosporia on solid medium containing 2% water-agar(2% WA) on eggs of E. paraensei, selecting the most efficient isolate (assay A), evaluate the ovicidal effect (destruction of eggs) of most effective isolate on supplemented agar culture media (assay B), and to evaluate the ovicidal capacity of crude enzymatic extract of most effective isolate on E. paraensei eggs (assay C). One thousand eggs of E. paraensei (assay A) were placed in Petri dishes containing 2% WA with one isolate of fungus P. chlamydosporia (VC1 or VC4) grown for 10 days, and without fungus as control. Both the treated and control group consisted of six replicates. After 15 days, approximately one hundred eggs were removed from each dish and classified according to the following parameters: type 1 effect, physiological effect without morphological damage to eggshell, where hyphae are observed attached to the shell; type 2 effect, lytic effect with morphological alteration of embryo and egg shell with hyphal penetration through the shell; and type 3 effect, lytic effect with morphological alteration of embryo and eggshell, in addition to hyphal penetration and internal egg colonization. In assay B, E. paraensei eggs were placed in Petri dishes with different supplemented agar culture media: 2% chitin- agar (2% AC), 2% corn-meal-agar (2% CMA), 2% WA and 2% starch- agar (2% SSA) with isolate VC4 (the most effective); in control group were not used fungus. Each treatment consisted of six replicates. After 25 days, one hundred eggs were removed from each dish and the ovicidal effect was evaluated according to the parameters already mentioned. In assay C, one thousand E. paraensei eggs were poured into Petri dishes with 5 ml of isolate VC4 crude extract constituting the treated group. The control group contained one thousand eggs in 10 ml of distilled water in Petri dishes. Each treatment consisted of six replicates. After 7 days, the total number of E. paraensei eggs present on each dish of the treated and control groups were counted according to the methodology described by Mukhtar and Pervaz. In assay A, there was no difference (p > 0.05) in ovicidal activity among the tested isolates; however, the highest percentage for ovicidal activity (type 3 effect) was demonstrated by the isolate VC4. In assay B, the culture medium starch agar showed the best results for the destruction of the eggs at the end of 25 days of interaction, with a percentage of 46.6%. In assay C, the crude extract of VC4 was effective in the destruction of E. paraensei eggs at the end of 7 days, with a percentage reduction of 53%. Results of in vitro experimental assay A, B and C have shown that P. chlamydosporia (VC1 and VC4) had negative influence on the E. paraensei eggs, and thus can be considered as a potential candidate for the biological control of this helminth.