It has been repeatedly shown earlier that some fish of a given batch reveal motion sickness (a kinetosis) at the transition from 1 g to microgravity. In the course of parabolic aircraft flight experiments, it has been demonstrated that kinetosis susceptibility is correlated with asymmetric inner ear otoliths (i.e., differently weighed statoliths on the right and the left side of the head) or with genetically predispositioned malformed cells within the sensory epithelia of the inner ear. Hitherto, the threshold of gravity perception for inducing kinetotic behaviour as well as the relative importance of asymmetric otoliths versus malformed epithelia for kinetosis susceptibility has yet not been determined. The following experiment using the ZARM drop-tower facility in Bremen, Germany, is proposed to be carried out in order to answer the aforementioned questions. Larval cichlid fish (Oreochromis mossambicus) will be kept in a camcorder-equipped centrifuge during the microgravity phases of the drops and thus receive various gravity environments ranging from 0.1 to 0.9 g. Videographed controls will be housed outside of the centrifuge receiving 0 g. Based on the videorecordings, animals will be grouped into kinetotically and normally swimming samples. Subsequently, otoliths will be dissected and their size and asymmetry will be measured. Further investigations will focus on the numerical quantification of inner ear supporting and sensory cells as well as on the quantification of inner ear carbonic anhydrase reactivity. A correlation between (1) the results to be obtained concerning the g-loads inducing kinetosis and (2) the corresponding otolith asymmetry/morphology of sensory epithelia/carbonic anhydrase reactivity will further contribute to the understanding of the origin of kinetosis susceptibility. Besides an outline of the proposed principal experiments, the present study reports on a first series of drop-tower tests which were undertaken to elucidate the feasibility of the proposal (especially concerning the question, if some 4.7 s of microgravity are sufficient to induce kinetotic behaviour in larval fish).

中文翻译：

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确定在鱼类中引起动能的重力阈值：落塔实验。

先前已经反复表明，某些给定批次的鱼在从1 g到微重力的转变过程中会出现晕车（运动病）。在抛物线飞机飞行实验过程中，已经证明运动病易感性与不对称内耳耳石（即头部左右两侧重量不同的吻合石）或感觉上皮细胞内遗传易位畸形细胞有关。内耳的 迄今为止，尚未确定重力诱导的动能行为的阈值以及不对称耳石与畸形上皮对动能易感性的相对重要性。以下是使用位于德国不来梅的ZARM落塔式设施进行的实验，为了回答上述问题，建议进行本发明。幼鱼丽鱼科鱼（莫桑比克罗非鱼）将在液滴的微重力阶段保持在装有便携式摄录机的离心机中，并因此接受0.1至0.9 g的各种重力环境。录制的控件将容纳在0 g离心机的外部。根据录像，将动物分为运动样本和正常游泳样本。随后，将解剖耳石，并测量其大小和不对称性。进一步的研究将集中在内耳支持和感觉细胞的数值量化以及内耳碳酸酐酶反应性的量化上。（1）将获得的有关引起g负荷的动反应的结果与（2）相应的耳石不对称性/感觉上皮的形态/碳酸酐酶反应性之间的相关性将进一步有助于对动反应易感性的理解。除了拟议的主要实验的大纲外，本研究报告还进行了第一批落塔试验，以阐明该建议的可行性（特别是关于这个问题，如果大约4.7 s的微重力足以引起动能学行为在幼鱼中）。