research

Currently, we are focusing on the detoxification enzymes in herbivorous insects.  Using various techniques of biochemistry and molecular biology, we are investigating how certain caterpillars can feed a broad range of host plants (generalists) or how other caterpillars are restricted to one or a few related host plants (specialists). Against plant defensive compounds, adapted insects have developed a variety of counter-defense strategies, shaping the intimate insect-plant interactions through the co-evolutionary arms race.  Insect herbivores can cope with a large diversity of toxic secondary metabolites by developing different tactics like behavioral avoidance, rapid excretion, target site mutation, enzymatic detoxification and/or sequestration.

Glycoside conjugation is one of the most important metabolic pathways for detoxification and biotransformation of a number of lipophilic xenobiotics and endobiotics. UDP-glycosyltransferases (UGTs) catalyze the conjugation of a sugar to a lipophilic molecule, generating water-soluble products which are less reactive, easily excretable and stably manageable, therefore protecting the cellular system from being damaged by toxic foreign compounds and regulating internal molecules more easily. We have identified a large collection of UGT genes in various arthropod species. Expanded searches of UGTs revealed the complete absence of UGT genes in Subphylum Chelicerata, except plant-feeding mites which have bacterial UGTs instead.  However, Myriapoda and Crustacea contain UGT genes in their genomes similar to Hexapoda UGTs. Taken together, it suggests that the UGT gene family probably had lost early in the Chelicerata lineage and subsequently re-gained in the herbivorous mites by horizontal gene transfer by unknown mechanisms.  We are searching for UGTs from other arthropod genomes to understand how the multigene family has evolved in arthropods and contributed to their intriguing adaptations. 

• Link to UDP-glycosyltransferase Nomenclature Committee

My research has been focused on the insect neuropeptide signaling system via G protein-coupled receptors (GPCRs), which plays an important role in diverse physiological and behavioral processes in insects. GPCRs represent the single largest family of membrane receptors and the most favorite class of drug targets in the pharmaceutical industry. The invertebrate GPCRs are relatively less known, despite their great potentials as bioactive targets. Neuropeptides, as GPCR ligands, are involved in a variety of pivotal mechanisms in insect physiology by triggering cellular response to GPCR ligands in the cellular membrane. Such bioactive small peptides, including neuropeptides, will give an insight not only on the signaling mechanisms, but also on the development of potential antagonists against the receptors of pest species.