Inhibitors of Cellulase Activities According to the Trophic Group of Termites (Insecta: Isoptera) from Daloa (Côte d'Ivoire)

Abstract

The presence of termites in the cocoa plantations and quarries of Côte d'Ivoire poses a threat to the producers of this sector. Producer yields are insufficient to cover the strong market demand. This situation leads to food insecurity for the population. Knowledge of the specific inhibitory molecules of digestive enzymes of termites is necessary to enhance the effectiveness of insecticides to optimize crop production. The present study was aimed to characterize termite cellulases according to the trophic group. Specifically, the influence of chemical agents on the cellulase activities of four humivorous (Cubitermes fungifaber) and xylophagous termites (Nasutitermes latifrons, Microcerotermes fuscotibialis and Amitermes guineensis) collected in Daloa during the October period was investigated. Thus, the cellulase activities were measured by the spectrophotometric method in the absence and in the presence of the concentrations of 1 and 5 mM of various chemical agents. The chemical agents used behaved differently on cellulase activities. Thus, Cu2+, Pb2+ and EDTA inhibited the cellulase activity of M. fuscotibialis more than 90% at concentrations of 1 and 5 mM, respectively, indicating the presence of a metalloprotein. On the other hand, that of the other two xylophagous species was slightly inhibited. In addition, the cellulase activity of C. Fungifaber was inhibited at the two respective concentrations by Cu2+ at about 70%. In conclusion, Cu2+, pb2+ and EDTA can be used in the formulation of some specific insecticides against humivorous and xylophagous termites.