Showing papers by "Hans-Peter Lenhof published in 2013"

NetworkTrail—a web service for identifying and visualizing deregulated subnetworks

Abstract: Summary: The deregulation of biochemical pathways plays a central role in many diseases like cancer or Parkinsons’s disease. In silico tools for calculating these deregulated pathways may help to gain new insights into pathogenic mechanisms and may open novel avenues for therapy stratification in the sense of personalized medicine. Here, we present NetworkTrail, a web service for the detection of deregulated pathways and subgraphs in biological networks. NetworkTrail uses a state-of-the-art integer linear programmingbased approach for this task and offers interfaces to the Biological Network Analyzer (BiNA) and Cytoscape Web for visualizing the resulting subnetworks. By providing an accessible interface to otherwise hard-to-use command line tools, the new web service enables nonexperts to quickly and reliably carry out this type of network analyses. Availability and implementation: NetworkTrail is a JavaServer Pages-based web service. The algorithm for finding deregulated subnetworks has been implemented in Cþþ. NetworkTrail is available at http://networktrail.bioinf.uni-sb.de/.

PresentaBALL — A powerful package for presentations and lessons in structural biology

Abstract: Structural biology is based on an important observation: the function of a biomolecule is determined by its three-dimensional structure and its physico-chemical properties. Hence, visualization, modeling, and simulation of molecular structures and of their properties are crucial tools of the field. Typically, the graphical interfaces to molecular modeling packages are aimed at domain experts with significant experience and require an extensive learning period. But in many scenarios, such as teaching, presentations, and demonstrations, it would be highly preferable to have an intuitive environment for showcasing molecular functionality. Ideally, it should support simple preparation of the presentations as well as their convenient display. To keep the user interface simple and focused, the environment should be particularly adapted to the processing of molecular structures. Here, we present such a presentation framework, called PresentaBALL, which uses established web technology standards to provide a freely configurable browser-based interface into the extensive modeling and visualization capabilities of the Biochemical Algorithms Library (BALL). The web interface is embedded into BALL's graphical frontend BALLView, and provides complete, interactive access to the loaded molecular data. PresentaBALL enables researchers in biology with basic knowledge in HTML, JavaScript, or Python to easily setup academic tutorials, demonstrations, or scientific presentations and lectures with 3D structure content and interactive workflows. Owing to its flexible design, other modern forms of teaching and presentation, such as massive open online courses (MOOC) can also use PresentaBALL as their core component. PresentaBALL is licensed under the GNU Public License (GPL) and will be made available in BALL/BALLView, starting with the upcoming release (1.5).

Efficient Interpretation of Tandem Mass Tags in Top-Down Proteomics

Abstract: Mass spectrometry is the major analytical tool for the identification and quantification of proteins in biological samples. In so-called top-down proteomics, separation and mass spectrometric analysis is performed at the level of intact proteins, without preparatory digestion steps. It has been shown that the tandem mass tag (TMT) labeling technology, which is often used for quantification based on digested proteins (bottom-up studies), can be applied in top-down proteomics as well. This, however, leads to a complex interpretation problem, where we need to annotate measured peaks with their respective generating protein, the number of charges, and the a priori unknown number of TMT-groups attached to this protein. In this work, we give an algorithm for the efficient enumeration of all valid annotations that fulfill available experimental constraints. Applying the algorithm to real-world data, we show that the annotation problem can indeed be efficiently solved. However, our experiments also demonstrate that reliable annotation in complex mixtures requires at least partial sequence information and high mass accuracy and resolution to go beyond the proof-of-concept stage.