Following the transition to the L4s, the larvae emerge from the mucosa within 6�C17 days. The parasite undergoes another cuticular moult, subsequently maturing to an adult. The pre-patent period of O. dentatum is,17�C20 days, although longer periods have been observed. Recent transcriptomic studies have provided first insights into the molecular biology of A12B4C3 different developmental stages of O. dentatum, leading to the characterization of a range of structural and functional molecules. In some studies of nematodes, various hydrolases have been identified as key molecules likely to play essential and specific roles in parasite development, cuticle collagen processing and/or moulting processes and thus represent potential drug targets for nematocides. Having available a practical in vitro culture system for O. dentatum provides a unique opportunity to assess the effects of specific and selective inhibitors on protein expression in this parasite. In the present study, we selected inhibitors of the most relevant hydrolase groups involved in the development and moulting of parasitic nematodes, based on their ability to inhibit these processes without AC 4 affecting viability and motility. We investigated the effects of these hydrolase inhibitors on the proteomic profile of O. dentatum during its transition from the L3 to L4 stage using an integrated two-dimensional gel electrophoretic, mass spectrometric and bioinformatic approach, taking advantage of all of the currently available transcriptomic datasets for this parasitic nematode. Drug resistance represents a major concern in the control of parasitic nematodes. Therefore, much research is directed towards the development of new agents in the treatment of nematode infections. Proteins involved in fundamental developmental processes in nematodes represent promising targets for the design of new and selective interventions. Hence, this study aimed at identifying and characterizing proteins involved in the larval development of O. dentatum, a model organism representative of parasitic nematodes of major socioeconomic impact. We applied an integrative approach combining in vitro drug testing with proteomic and bioinformatic analyses to provide first insights into larval development in O. dentatum. To generate a development-inhibited phenotype for O. dentatum, hydrolase inhibitors were selected based on their ability to impede the moulting and development of larvae without affecting their viability and motility. Enzyme inhibitors were tested to cover the most relevant hydrolase classes known to be involved in the highly sophisticated moulting process in various nematode species. Significant inhibition of moulting and development has been described previously in a range of nematodes and could be confirmed in O. dentatum for the three inhibitors, ophenanthroline, sodium fluoride and iodoacetamide.