SPNConverter

SPNConverter is a Java-based plug-in for Cytoscape that automates the preparation of biological networks for dynamic simulation with the Signaling Petri Net (SPN) simulator bundled in BioLayout Express3D. It was written by Jennifer E. Dent, Xinyi Yang, and Christine Nardini at the CAS-MPG Partner Institute for Computational Biology, and published as an application note in Bioinformatics (29(19):2507-2508, 2013). The code is distributed under the GNU General Public License v3 through the Cytoscape App Store, though the store listing no longer offers a working download of the aging plug-in.

Functionally the tool is a narrowly-scoped format converter. It takes a curated pathway map in Systems Biology Markup Language (SBML), typically authored in Cytoscape or in CellDesigner (see CellDesigner), and emits a GraphML file (GraphML) suitable for the SPN simulator. Its distinguishing step is not merely a syntactic translation: the SPN model requires an explicit "transition gate" node inserted between every pair of interacting molecules, and the output is expressed in a modified Edinburgh Pathway Notation rather than plain node-edge GraphML. Historically these transition gates had to be added by hand, which is tedious and error-prone on the large maps SPN is designed to run, so automating the transformation is the plug-in's principal contribution.

The purpose of the SPN simulator itself is to reveal trends in molecules' activity levels in response to an external stimulus, offering a coarse dynamic view of signaling without the detailed kinetic rate constants that a full stochastic or ODE model would demand. SPNConverter therefore acts as a bridge between static topological analysis, where a pathway is treated as a fixed graph, and dynamic simulation, letting researchers move an existing SBML/CellDesigner curation into a simulatable form with a single conversion.

The main limitations are scope and longevity. SPNConverter is not a general graph-interchange utility: it targets one specific downstream simulator and one flavor of GraphML, so it is of little use outside the SPN/BioLayout workflow, and general SBML-to-graph needs are better served by tools such as cy3sbml or SBFC. It was built against the Cytoscape 2.x plug-in API, predating the modern Cytoscape 3 app architecture, and it does not perform kinetic simulation on its own. For discrete Petri-net execution inside Cytoscape, the later PetriScape plug-in is a more actively maintained alternative.