Natural products are words and messages in a global communication system of species interactions. They have a special meaning and will effect an answer, which is not constant, but depends on the given situation. We are just beginning to understand this language of nature, to compile the vocabulary and to decipher the grammar.
Natural products are weapons and defence systems, attractants and repellents, or simply communication signals which are important for the survival of species. Development of bacterial resistance to antibiotics is a logical and unavoidable response to environmental effects, which we can only overcome by a better understanding of the 'microbial conversation'. As a consequence, the investigation of ecological interactions and a continuous and efficient search for new natural products with potential application in medicine is a steady and indispensable task. However, since the number of natural products is limited, every newly isolated product will diminish the chances to find further hits. And every re-isolated known compound is an avoidable loss of time and money.
Two techniques are widely applied to overcome these problems. The first one is activity-directed high throughput screening, which is an expensive and fully automated, mainly industrial process; the other one is the so-called chemical screening. We are using a third technique, a type of dragnet search, where we compare easily accessible data of isolated and purified compounds with comprehensive databases of more than 50,000 marine and microbial natural products, AntiBase or MarinLit. Comparison of sub-structures, NMR, MS, and UV data allows a very fast decision as to whether a given natural product is already known or not, which enables us to save time and resources, avoid frustration, and to concentrate on the really new topics.
This presentation will explain modern dereplication techniques using MS/MS, 2D NMR and database methods. The procedure will be highlighted by some simple and some very complex examples from our ongoing research on marine bacteria.
Professor Laatsch (University of Gott) was invited to Swinburne under the Board of Research Visiting Professor Grant Scheme, and this lecture was presented as part of the PVC(R) Visiting Professor Lecture Series.