Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
Laboratoire de Physiologie Cellulaire et Végétale, UMR5168 CNRS-CEA-INRA-Université de Grenoble Alpes, Institut de Recherche en Science et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cédex 9, France.
Sci Rep. 2017 Jun 19;7(1):3826. doi: 10.1038/s41598-017-03741-6.
Diatoms are a fundamental microalgal phylum that thrives in turbulent environments. Despite several experimental and numerical studies, if and how diatoms may profit from turbulence is still an open question. One of the leading arguments is that turbulence favours nutrient uptake. Morphological features, such as the absence of flagella, the presence of a rigid exoskeleton and the micrometre size would support the possible passive but beneficial role of turbulence on diatoms. We demonstrate that in fact diatoms actively respond to turbulence in non-limiting nutrient conditions. TURBOGEN, a prototypic instrument to generate natural levels of microscale turbulence, was used to expose diatoms to the mechanical stimulus. Differential expression analyses, coupled with microscopy inspections, enabled us to study the morphological and transcriptional response of Chaetoceros decipiens to turbulence. Our target species responds to turbulence by activating energy storage pathways like fatty acid biosynthesis and by modifying its cell chain spectrum. Two other ecologically important species were examined and the occurrence of a morphological response was confirmed. These results challenge the view of phytoplankton as unsophisticated passive organisms.
硅藻是一种在动荡环境中茁壮成长的基本微藻门。尽管已经进行了一些实验和数值研究，但硅藻是否以及如何能从动荡中受益仍然是一个悬而未决的问题。其中一个主要论点是，动荡有利于营养物质的吸收。形态特征，如没有鞭毛、存在刚性外壳和微米大小，支持了动荡对硅藻可能产生的被动但有益的作用。我们证明，在非限制营养条件下，硅藻实际上会对动荡做出积极响应。TURBOGEN 是一种产生自然水平微尺度动荡的典型仪器，用于使硅藻暴露于机械刺激下。差异表达分析，加上显微镜检查，使我们能够研究 Chaetoceros decipiens 对动荡的形态和转录响应。我们的目标物种通过激活脂肪酸生物合成等能量储存途径，并通过改变其细胞链谱来对动荡做出响应。另外两种具有重要生态意义的物种也进行了检查，并证实了形态响应的发生。这些结果挑战了浮游植物是简单被动生物的观点。
