Department of Biology, University of Louisiana at Lafayette , Lafayette, LA 70504-2451 , USA.
Biol Open. 2012 Jun 15;1(6):582-7. doi: 10.1242/bio.2012695. Epub 2012 May 4.
Sea anemones discharge cnidae ('stinging capsules' including nematocysts) to capture prey and to defend themselves. In the present study, we tested the relationship between the force of test probes striking feeding tentacles and discharge of microbasic p-mastigophore nematocysts into the test probes. In seawater alone, the response curve is bimodal with maximal discharge observed at 0.33 and 1.10 millinewtons (mN) and with minimal discharge at 1.50 mN. Upon activating chemoreceptors for N-acetylated sugars, maximal discharge is observed across a broad range of smaller forces from 0.16 to 0.9 mN before decreasing to a minimum at 1.50 mN. Likewise, in the presence of nearby vibrations at key frequencies, maximal discharge is observed over a broad range of smaller forces before decreasing to a minimum at 1.50 mN. It appears that sensory input indicating proximity of potential prey expands the range of small forces of impact that stimulate maximal discharge (i.e. to less than 1.10 mN) but not at larger forces of impact (i.e. at approximately 1.50 mN). Thus, contact by small prey would stimulate maximal discharge, and all the more so if such contact is accompanied by specific odorants or by vibrations at specific frequencies. Nevertheless, anemones would not maximally discharge nematocysts into large animals that blunder into contact with their tentacles.
海葵通过射出刺丝囊（包括刺细胞的“刺丝囊”）来捕捉猎物和自卫。在本研究中，我们测试了测试探针撞击进食触须的力与微碱性 p-游仆虫刺丝囊排入测试探针之间的关系。在海水中单独作用时，响应曲线呈双峰型，最大排放发生在 0.33 和 1.10 毫牛顿（mN），最小排放发生在 1.50 mN。在激活 N-乙酰化糖的化学感受器后，在从 0.16 到 0.9 mN 的较小力范围内，最大排放发生在较宽的范围内，然后在 1.50 mN 处降至最小。同样，在关键频率附近存在振动时，在较小力的较大范围内观察到最大排放，然后在 1.50 mN 处降至最小。似乎表明潜在猎物接近的感觉输入扩大了刺激最大排放的较小冲击力的范围（即小于 1.10 mN），但不适用于较大的冲击力（即约 1.50 mN）。因此，较小的猎物接触会刺激最大排放，如果这种接触伴随着特定的气味或特定频率的振动，效果会更明显。然而，对于误撞到其触须的大型动物，海葵不会将刺丝囊最大程度地排入其中。
