Ontologies have become an important means for structuring knowledge and defining semantic information retrieval systems. Ontology engineering requires a significant effort, and recent researches show that human language technologies are useful means to acquire or update ontologies from text. In this paper we present DYNAMO, a tool based on a Multi-Agent System, which aims at assisting ontologists during the ontology building and evolution processes. This work is carried out in the context of the DYNAMO project. The main novelty of the agent system is to take advantage of text extracted terms and lexical relations together with some quantitative features of the corpus to guide the agents when self-organizing. We exhibit the first experiment of ontology building that shows promising results, and helps us to identify key issues to be solved to the Dynamo system behavior and the resulting ontology.