Clostridium difficile is the main cause of antibiotic-associated and chronic diarrhoe and colitis in hospitals and residential care homes for the elderly of the Western World. A therapeutic antibiotic treatment is rarely successful, because competing enteric bacteria are killed and C. difficile can survive due to its ability to form endospores. A specific antibacterial peptide against C. difficile would be a therapeutic breakthrough. Aim of this project is therefore identification and analysis of a novel peptide antibiotic against C. difficile from a human hemofiltrate peptide library of the competence center Ulm Peptide Pharmaceuticals (U-PEP). Positive peptide fractions will be purified together with U-PEP (Dr. Rosenau) to identify the peptide with antibiotic activity. Determination of amino acid sequence, artificial synthesis of the peptide, test of specificity versus Gram-positive and –negative bacteria, and synthesis of variants for increased activity will follow. The mechanism of action of the peptide will be determined by using fluorescence-labelled peptides, microscopy, and fluorescent dyes.

Development of a novel high-throughput purification technique for peptides based on aptamer functionalized particles

Peptide libraries from human origin represent a uniquely rich ressource for active compounds for a variety of purposes. However, screening of those libraries for hit fractions leads to the need of purification down to the single effector peptide. Based on a proteomic approach a technique will be developed to easily create affinity molecules (aptamers) against all peptides within a sample, which are then be used to produce a tool-box of functionalized particles for larger scale purification of singe peptides.

Cell engineering as well as bioprocess development are essential steps to optimise a biopharmaceutical production process. In a novel, innovative approach, components of a human hemofiltration peptide library (U-PEP, Dr. Rosenau) will be used and analyzed in regard to their potential to enhance bioprocess relevant parameters as the improvement in product formation, secretion, proliferation and stability of antibody producing recombinant human CAP®-cell lines (Prof. Hannemann and Dr. Handrick, University of applied Sciences Biberach). The project will be performed in close cooperation with the group of Dr. Rosenau from the U-PEP (University Ulm). Analysis of the molecular mechanisms of action by molecular biology, cell biological and biochemical methods are integral parts of the project.