Enzimas digestivas do bicho-mineiro do cafeeiro Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae) / Coffee leaf miner's digestive enzymes Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae)

RESUMO

Os insetos possuem diferentes enzimas digestivas que catalisam as reações de hidrólise do alimento consumido e essas se diferenciam entre os insetos de acordo com suas dietas e estado fisiológico. Foram avaliadas as atividades de algumas enzimas digestivas da praga do cafeeiro - Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae) - popularmente conhecida como bicho-mineiro do cafeeiro, para o entendimento de seu processo digestivo. Lagartas do bicho-mineiro do cafeeiro foram coletadas em campo e em casa-de-vegetação. O extrato enzimático utilizado foi obtido pela maceração das lagartas em água (4ºC). Determinaram-se os pH's ótimos e as atividades das enzimas α e β-glicosidases, α-amilase, aminopeptidase, fosfatase alcalina, sacarase, trealase e tripsina, incubando o extrato enzimático do bicho-mineiro do cafeeiro com substratos específicos. A análise dos resultados sugere que o processo digestivo e o ambiente intestinal do bicho-mineiro do cafeeiro sejam similares com o dos demais lepidópteros encontrados na literatura.

ABSTRACT

Insects are fitted with different digestive enzymes that catalyses the food hydrolysis. Those enzymes differ from one insect to another according to their diets and physiological status. In this work, one intended to verify the activities of some digestive enzymes of the coffee leaf miner - Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae) - as a pre-requisite to understand its digest process, since this insect is a major plague in coffee production systems. Coffee leaf miner caterpillars were collected in fields and in greenhouse. The enzyme extract utilized in determining the enzyme activities was obtained through grinding the caterpillars in cold water. The optimum pH and the activities of the enzymes α and β-glucosidases, α-amylase, aminopeptidase, alkaline phosphatase, saccharase, trehalase and trypsin were measured by incubating the enzyme extract with specific substrates. The analysis of the optimum pH's indicated that the digestive process and intestinal environment of this insect are similar to another lepidopterans consulted in the literature.