We compared two metabolome profiles of a small centric diatom species, Stephanodiscus hantzschii Grun., grown under conditions with enriched nutrients but different temperatures. This species proliferates in eutrophic rivers during winter. We investigated the population dynamics and internal metabolite changes of Stephanodiscus by performing a simple culture experiment at different temperatures (5 and 15°C). We applied the ¹H nuclear magnetic resonance (NMR) technique to fully grown cells to obtain the metabolite profiles of S. hantzschii. Growth rates were significantly different at different temperature conditions (0.99 ± 0.11 day⁻¹ at 15°C and 0.21 ± 0.12 day⁻¹ at 5°C, n = 10). Characterized metabolites included saturated and unsaturated fatty acids, AXP (including AMP, ADP and ATP), and UDP-glucose and UDP-galactose, all of which are important for energy metabolism. These metabolites were abundant within S. hantzschii cells grown at 15°C but were not prolific in those grown at 5°C. Furthermore, other ¹H NMR spectrum uncovered very little amounts of metabolites. Based on these observations of cell growth rate, although required nutrients were supplied, colder temperatures suppressed population growth through the deactivation of various internal metabolisms. Thus, winter proliferation of this species is opportunistic, implying that survival success led to dominance in freshwater ecosystems with neither resource competition nor grazing pressure.

中文翻译：

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核磁共振在分析冬季硅藻大花代谢特征中的应用

我们比较了在营养丰富但温度不同的条件下生长的小中心硅藻物种Stephanodiscus hantzschii Grun。的两种代谢组谱。在冬季，该物种在富营养化的河流中扩散。我们通过在不同的温度（5和15°C）下进行简单的培养实验，研究了Stephanodicus的种群动态和内部代谢物的变化。我们将¹ H核磁共振（NMR）技术应用于完全生长的细胞，以获得汉氏链球菌的代谢产物谱。在不同的温度条件下，增长率明显不同（15°C时为0.99±0.11天^-1，5 °C时为0.21±0.12天^-1，n  = 10）。表征的代谢产物包括饱和和不饱和脂肪酸，AXP（包括AMP，ADP和ATP）以及UDP-葡萄糖和UDP-半乳糖，所有这些对于能量代谢都很重要。这些代谢物在15°C下生长的汉氏链球菌细胞中含量丰富，但在5°C下生长的细胞中却不丰富。此外，其他¹1 H NMR光谱发现很少的代谢物。基于这些细胞生长速率的观察结果，尽管提供了必需的营养素，但较低的温度通过各种内部代谢的失活抑制了群体的生长。因此，该物种的冬季繁殖是机会性的，这意味着生存成功导致既没有资源竞争也没有放牧压力的淡水生态系统占优势。