UMR7156 Université de Strasbourg/CNRS, Génétique Moléculaire, Génomique et Microbiologie, Département Micro-organismes, Génomes, Environnement, Strasbourg, France.
ISME J. 2012 Jul;6(7):1391-402. doi: 10.1038/ismej.2011.198. Epub 2012 Jan 12.
Euglena mutabilis is a photosynthetic protist found in acidic aquatic environments such as peat bogs, volcanic lakes and acid mine drainages (AMDs). Through its photosynthetic metabolism, this protist is supposed to have an important role in primary production in such oligotrophic ecosystems. Nevertheless, the exact contribution of E. mutabilis in organic matter synthesis remains unclear and no evidence of metabolite secretion by this protist has been established so far. Here we combined in situ proteo-metabolomic approaches to determine the nature of the metabolites accumulated by this protist or potentially secreted into an AMD. Our results revealed that the secreted metabolites are represented by a large number of amino acids, polyamine compounds, urea and some sugars but no fatty acids, suggesting a selective organic matter contribution in this ecosystem. Such a production may have a crucial impact on the bacterial community present on the study site, as it has been suggested previously that prokaryotes transport and recycle in situ most of the metabolites secreted by E. mutabilis. Consequently, this protist may have an indirect but important role in AMD ecosystems but also in other ecological niches often described as nitrogen-limited.
眼虫是一种在酸性水生环境（如泥炭沼泽、火山湖和酸性矿山排水（AMD））中发现的光合原生生物。通过其光合作用代谢，这种原生生物应该在贫营养生态系统的初级生产中发挥重要作用。然而，眼虫在有机物合成中的确切贡献仍不清楚，到目前为止，还没有证据表明这种原生生物会分泌代谢物。在这里，我们结合了原位蛋白组代谢组学方法来确定这种原生生物积累或潜在分泌到 AMD 中的代谢物的性质。我们的结果表明，分泌的代谢物主要由大量氨基酸、多胺化合物、尿素和一些糖组成，但没有脂肪酸，这表明在这个生态系统中存在有选择的有机物贡献。这种产生可能对研究地点存在的细菌群落产生至关重要的影响，因为之前有人提出，原核生物会在原位运输和回收眼虫分泌的大部分代谢物。因此，这种原生生物可能在 AMD 生态系统中以及其他通常被描述为氮限制的生态位中发挥间接但重要的作用。
