Effects of simulated weightlessness on fish otolith growth: Clinostat versus Rotating-Wall Vessel
Effects of simulated weightlessness on fish otolith growth: Clinostat versus Rotating-Wall Vessel
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DOI：
10.1016/j.asr.2011.04.014
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发表时间：
2011-09-01
影响因子：
2.6
通讯作者：
Anken, Ralf
中科院分区：
文献类型：
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作者：
Brungs, Sonja;Hauslage, Jens;Anken, Ralf
刺激依赖是感官系统发育的一个普遍特征。先前已有研究表明，超重力会减缓晚期慈鲷（Oreochromis mossambicus）和斑马鱼（Danio rerio）内耳重石（耳石）的生长，而太空飞行期间的微重力则会产生相反的效果，即剑尾鱼（Xiphophorus heleri）和慈鲷后期胚胎的耳石大于1g。这些和相关的研究提出，耳石的生长是通过反馈机制主动调节的，以产生适当的物理容量的测试质量。利用地面技术模拟失重，长期旋转（CR；暴露在一个快速旋转的单轴旋转器上）导致晚期慈鲷鱼的石体大于1g。短期壁血管旋转（WVR，也被认为是一种模拟失重的方法）后，早期斑马鱼胚胎中也发现了比正常大的耳石。这些结果与从太空飞行中获得的剑尾结果基本一致。因此，鱼类内耳耳石的生长似乎是评估特定模拟装置提供的“模拟失重”质量的适当参数。由于CR和WVR在世界范围内使用小型标本模拟地面失重条件，我们被提示以发育中的稚鱼为模式生物直接比较CR和WVR对耳石生长的影响。当耳石原基在耳室（重力感知）和耳囊（听力）内开始钙化时，同时对动物进行CR和WVR；耳石分别是小柱耳石和矢状耳石。随后进行了三次这样的试验，使用了三批不同的鱼。当动物开始孵化时，跑步就停止了。在所有三组实验中，CR导致耳石的生长大于正常耳石，而WVR对这些耳石的生长没有影响。对于矢状体，CR导致三组中有一组结石比正常结石大。其他CR组和所有WVR组对矢状面生长无影响。这些结果清楚地表明，CR而不是WVR可以作为一种模拟失重的装置，以慈鲷为模式生物。由于WVR早前已被证明会影响斑马鱼的耳石生长，动物的生活方式（口繁殖与产卵）似乎相当重要。需要使用各种模拟技术（包括，例如磁悬浮和随机定位）和各种物种进行进一步的研究，以便确定最合适的技术来模拟特定模式生物的失重状态。(c) 2011年cospar。Elsevier Ltd.出版。版权所有。
Stimulus dependence is a general feature of developing sensory systems. It has been shown earlier that the growth of inner ear heavy stones (otoliths) of late-stage Cichlid fish (Oreochromis mossambicus) and Zebrafish (Danio rerio) is slowed down by hypergravity, whereas microgravity during space flight yields an opposite effect, i.e. larger than 1 g otoliths, in Swordtail (Xiphophorus helleri) and in Cichlid fish late-stage embryos. These and related studies proposed that otolith growth is actively adjusted via a feedback mechanism to produce a test mass of the appropriate physical capacity. Using ground-based techniques to apply simulated weightlessness, long-term clinorotation (CR; exposure on a fast-rotating Clinostat with one axis of rotation) led to larger than 1 g otoliths in late-stage Cichlid fish. Larger than normal otoliths were also found in early-staged Zebrafish embryos after short-term Wall Vessel Rotation (WVR; also regarded as a method to simulate weightlessness). These results are basically in line with the results obtained on Swordtails from space flight.Thus, the growth of fish inner ear otoliths seems to be an appropriate parameter to assess the quality of "simulated weightlessness" provided by a particular simulation device. Since CR and WVR are in worldwide use to simulate weightlessness conditions on ground using small-sized specimens, we were prompted to directly compare the effects of CR and WVR on otolith growth using developing Cichlids as model organism. Animals were simultaneously subjected to CR and WVR from a point of time when otolith primordia had begun to calcify both within the utricle (gravity perception) and the saccule (hearing); the respective otoliths are the lapilli and the sagittae. Three such runs were subsequently carried out, using three different batches of fish. The runs were discontinued when the animals began to hatch.In the course of all three runs performed, CR led to larger than normal lapilli, whereas WVR had no effect on the growth of these otoliths. Regarding sagittae, CR resulted in larger than normal stones in one of the three runs. The other CR runs and all WVR runs had no effect on sagittal growth. These results clearly indicate that CR rather than WVR can be regarded as a device to simulate weightlessness using the Cichlid as model organism. Since WVR has earlier been shown to affect otolith growth in Zebrafish, the lifestyle of an animal (mouth-breeding versus egg-laying) seems to be of considerable importance. Further studies using a variety of simulation techniques (including, e.g. magnetic levitation and random positioning) and various species are needed in order to identify the most appropriate technique to simulate weightlessness regarding a particular model organism. (C) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.