Responses of marine planktonic protists to amino acids: feeding inhibition and swimming behavior in the ciliate Favella sp.
Responses of marine planktonic protists to amino acids: feeding inhibition and swimming behavior in the ciliate Favella sp.
复制标题
海洋浮游原生生物对氨基酸的反应：纤毛虫的摄食抑制和游泳行为。
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Kelley J. Bright
中科院分区：
文献类型：
--
作者：
S. Strom;G. Wolfe;Kelley J. Bright
甲藻Heterocapsa triquetra上的tintinnid Favella sp.的摄食率被一些溶解的游离氨基酸（DFAA）抑制，与抑制成反比的氨基酸侧链的大小。最具抑制性的化合物（缬氨酸、半胱氨酸、脯氨酸、丙氨酸和丝氨酸）在浓度为20 µM时将摄食率降低至对照组的<20%。抑制作用呈剂量依赖性，阈值约为100 mg/kg。200 nM的脯氨酸，并且不依赖于纤毛虫的进食史（良好进食vs饥饿）。抑制发生迅速（暴露后<5分钟），并在去除DFAA后部分可逆。游泳的详细分析并没有揭示一致的变化，在Favella属。行为暴露于抑制性氨基酸。与Favella sp.相反，异养甲藻Gyro- dinium dominans对20 µM DFAAs没有表现出摄食反应，而tintinid Coxliella sp.对Favella sp.中活性氨基酸的子集作出反应，减少了摄食（约为对照率的50%）。我们的发现，沿着一些抑制性化合物在nM浓度下在天然沃茨中的流行，指出了这些氨基酸的信号功能。然而，Favella sp.中的摄食威慑与DFAA的典型引诱剂或刺激作用相反，DFAA的典型引诱剂或刺激作用已被记录用于从细菌到后生动物的生物体。该信号的信息内容尚不清楚，但可能与Favella sp在悬浮摄食期间检测猎物质量有关。
Feeding rates of the tintinnid Favella sp. on the dinoflagellate Heterocapsa triquetra were inhibited by a number of dissolved free amino acids (DFAAs), with inhibition inversely proportional to the size of the amino acid side chain. The most inhibitory compounds (valine, cysteine, proline, alanine, and ser- ine) reduced feeding to <20% of the control rate at a concentration of 20 µM. Inhibition was dose-depen- dent, with a threshold of ca. 200 nM for proline, and did not depend on ciliate feeding history (well-fed ver- sus starved). Inhibition occurred rapidly (<5 min after exposure) and was partially reversible upon removal of DFAAs. Detailed analysis of swimming did not reveal consistent changes in Favella sp. behavior upon exposure to inhibitory amino acids. In contrast to Favella sp., the heterotrophic dinoflagellate Gyro- dinium dominans showed no feeding response to 20 µM DFAAs, while the tintinnid Coxliella sp. exhib- ited reduced feeding (to approximately 50% of control rates) in response to a subset of the amino acids active in Favella sp. Our findings, along with the prevalence of some inhibitory compounds at nM concentrations in natural waters, point to a signaling function for these amino acids. Feeding deterrence in Favella sp. is, however, contrary to the typical attractant or stimula- tory role of DFAAs, which has been documented for organisms ranging from bacteria to metazoans. The information content of the signal remains unclear but may be related to detection of prey quality during sus- pension feeding by Favella sp.