In the field of functional biology where users rely on different heterogeneous data sources and applications the problem of interoperability and integration is of immense importance. In this paper, we outline our approach which addresses this demands with a client-side integration platform. This componentbased and dynamically adaptable client platform supports integration of service-specific Interaction Components. These components are loosely coupled encapsulating heterogeneous biological data as well as method services and are realized as extended JavaBeans. A mediator framework is developed, in order to provide an opportunity to integrate previously unknown data models and web services as well as new local software tools. Instead of building a canonical data schema, the different data models are mapped to a generic data representation. A partial semantic integration is achieved by a composition of several basic transformation steps. These are realized in an extensible set of Mediator Components. Such components can be described by XML-based languages or within Java directly.