Optical imaging of physiological functions in transparent animals
PD Dr. Ralph Pirow, Universität Münster
Plenarvortrag DZG-Tagung, Münster 2006
Sauerstoffmangelsituationen in der Umwelt können eindrucksvolle physiologische
Veränderungen bei Tieren hervorrufen. Beim Wasserfloh Daphnia magna führen
solche Bedingungen zu einer vielfachen Erhöhung der Hämoglobinkonzentration in
der Hämolymphe. Die Transparenz dieser Tiere macht es möglich, die
physiologischen Konsequenzen des "Rotwerdens" mit Hilfe von optischen Methoden
näher zu untersuchen.
Abstract of the presentation at the DZG-meeting:
One of the challenges of modern biology is to understand how proteins, protein networks, cells, tissues and organs interact at different levels of biological organization to establish complex body functions. A mechanistic understanding of these hierarchically structured, dynamic systems depends not only on analytical concepts and methodologies but also on the technology to obtain quantitative information on key systems parameters, often in high spatial and/or temporal resolution. Recent advances in electronics, optics, microscopy, computer sciences, and chemistry have made it possible to retrieve such information by choosing animal models which are distinguished by a high level of transparency. The present paper shows how the application of optical techniques has advanced our understanding of the homeostatic capabilities of the zooplankter Daphnia spp., which has become a model organism of evolutionary and ecological functional genomics. The methodical survey includes the spectral imaging of pH and Hb oxygen saturation in the animal´s circulatory fluid, phosphorescence lifetime imaging of oxygen partial pressure distributions, the evaluation of NADH fluorescence intensity as an indicator of the tissue oxygenation state, and digital motion analysis of biological pumps and moving fluids. These data are brought into quantitative relationships based on fundamental laws of physics and chemistry, and computer-aided modelling and simulation is used to comprehend the functioning of homeostatic systems which enable Daphnia to cope with environmental oxygen and acid stress.