GENETIC-CHARACTERIZATION OF A NEW APIS-MELLIFERA ESTERASE

A new esterase, denoted esterase-1a (Est-1a), was first identified by starch gel electrophoresis of abdomen extracts from adult drones of Ap is mellifera. This enzyme was developed only with 4-methylumbelliferyl eaters and its inhibition properties suggest that it is an arylestera se. It does not contain reactive sulfhydryl groups and has a monomeric structure. A genetic variant (Est-1a(92)) was detected at an average frequency of 4.2% in drones collected from five apiaries. Genetic link age studies showed no close linkage between the Est-1a locus and the g enetic markers Est-6, Mdh-1 and Hk-1. Esterase-1a activity was observe d in the reproductive and digestive tracts of sexually mature drones, queens and egg-laying workers, suggesting its association with sexual mat maturation. In view of its presence in the egg and its restricted localization in the middle portion of the digestive tract (midgut), th is enzyme may play a proteolytic role in early embryonic development.