School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
J R Soc Interface. 2012 Jul 7;9(72):1438-49. doi: 10.1098/rsif.2011.0715. Epub 2012 Jan 4.
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.
了解重力对生物机体的影响对于未来太空任务的成功至关重要。以前在地球轨道上的研究表明，与在地球上的运动相比，普通果蝇（Drosophila melanogaster）在微重力下走得更快、更频繁。然而，发射前的飞行准备程序和所承受的力使得难以在地球表面实施一种控制，使果蝇经历相同的主要物理和环境变化序列。为了解决这些行为异常的不确定性，我们在基于地球的实验室中研究了 D. melanogaster 在伪失重环境（0g*）中的行走路径。我们使用超导螺线管产生的强磁场对果蝇施加抗磁性力，以平衡重力。同时，另外两组果蝇在空间变化的磁场中暴露于伪超重力环境（2g*）和正常重力环境（1g*）中。与 1g相比，果蝇在 0g中的平均速度更大，在 2g中的平均速度更小。与 1g相比，果蝇在 0g中的平均平方距离随时间的增长更快，在 2g中的增长更慢。我们没有观察到磁场对果蝇行走的其他明显影响，最高可达 16.5 T。我们比较了抗磁性模拟失重与轨道航天器中失重的影响，并将异常行为的原因确定为有效重力的改变。
