Effect of magnetically simulated zero-gravity and enhanced gravity on the walk of the common fruitfly†

School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
Journal of The Royal Society Interface (Impact Factor: 3.92). 01/2012; 9(72):1438-49. DOI: 10.1098/rsif.2011.0715
Source: PubMed


Understanding the effects of gravity on biological organisms is vital to the success of future space missions. Previous studies in Earth orbit have shown that the common fruitfly (Drosophila melanogaster) walks more quickly and more frequently in microgravity, compared with its motion on Earth. However, flight preparation procedures and forces endured on launch made it difficult to implement on the Earth's surface a control that exposed flies to the same sequence of major physical and environmental changes. To address the uncertainties concerning these behavioural anomalies, we have studied the walking paths of D. melanogaster in a pseudo-weightless environment (0g*) in our Earth-based laboratory. We used a strong magnetic field, produced by a superconducting solenoid, to induce a diamagnetic force on the flies that balanced the force of gravity. Simultaneously, two other groups of flies were exposed to a pseudo-hypergravity environment (2g*) and a normal gravity environment (1g*) within the spatially varying field. The flies had a larger mean speed in 0g* than in 1g*, and smaller in 2g*. The mean square distance travelled by the flies grew more rapidly with time in 0g* than in 1g*, and slower in 2g*. We observed no other clear effects of the magnetic field, up to 16.5 T, on the walks of the flies. We compare the effect of diamagnetically simulated weightlessness with that of weightlessness in an orbiting spacecraft, and identify the cause of the anomalous behaviour as the altered effective gravity.

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Available from: F. Javier Medina
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    • "The technique of stable diamagnetic levitation has been described in detail elsewhere, e.g. [5,34,36]. Seedlings and imbibed seeds of Arabidopsis levitated in the same position in the magnet as the water droplet, since the magnetic mass susceptibility of most of the plant tissues is similar to that of water [37]. Under these conditions, the gravitationally-induced stresses on such tissues are expected to be much reduced by diamagnetic levitation [35]. "
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