Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 6: Physics of Cells II
BP 6.3: Vortrag
Montag, 26. März 2012, 15:45–16:00, H 1028
The Mechanobiology of Physarum polycephalum — •Christina Oettmeier1,2, Erik Bernitt1,2, and Hans-Günther Döbereiner1,2 — 1Institut für Biophysik, Universität Bremen, 28334 Bremen — 2Mechanobiology Institute, National University of Singapore, 117411 Singapore
We characterize the mechanobiological properties of P. polycephalum. This amoeboid slime mold can reach large sizes and is one single, multinuclear cell. By using microplasmodia, we introduce a reliable and reproducible system for the study of network formation and individual cell motility. Microplasmodia are a special growth form, quasi-spherical in shape and 200-500 microns small. Created by cultivation in shaking culture, they exhibit the same actin-myosin based oscillations as the large plasmodia. We monitor cell dynamics in different ways: First, by observing area oscillations with bright-field microscopy, whereby the spatio-temporal dynamics of focal area and contour could be analyzed. Fast oscillations with a period of 1-2 min as well as a superimposed slow oscillation with a period of about 20 min were found. The second method, calcium imaging with the ratiometric dye Fura-2-AM, was used to clarify the correlation between biochemical signalling and contractions. These correlate with a low local calcium concentration, corresponding to Physarum’s calcium-inhibited actin-myosin interaction. Third, the viscoelastic properties were investigated using a microindentation setup. In conclusion, we have shown that microplasmodia are very well suited to study the mechanobiology of Physarum due to the reliability, robustness and precision of the system.