Quantitative macromolecular patterns in phytoplankton communities resolved at the taxonomical level by single-cell Synchrotron FTIR-spectroscopy
Quantitative macromolecular patterns in phytoplankton communities resolved at the taxonomical level by single-cell Synchrotron FTIR-spectroscopy
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DOI：
10.1186/s12870-019-1736-8
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发表时间：
2019-04-15
影响因子：
5.3
通讯作者：
Wilhelm, Christian
中科院分区：
文献类型：
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作者：
Fanesi, Andrea;Wagner, Heiko;Wilhelm, Christian
背景资料：关于浮游植物生物量的批量分析的技术限制限制了我们对自然种群中碳通量的理解，因此，限制了对水生生态系统中碳、营养物和能量循环的理解。在这项研究中，我们利用同步辐射红外显微光谱和偏最小二乘回归（PLSr）算法，同时定量蛋白质，脂肪和碳水化合物的含量在单细胞水平上在模拟浮游植物群落（由蓝藻、绿球藻和硅藻组成）在两种温度下生长结果：生成的用于定量细胞大分子的PLSr模型呈现高质量拟合（R-2 >= 0.90）和低预测误差（RMSEP 2-6%干重）。回归系数表明，每种大分子的预测并不完全取决于该化合物对应的光谱特征，而是取决于所有主要大分子库，反映了整体细胞碳平衡的调整。通过核密度估计器研究的单细胞分析表明，大分子的密度分布模式在15 ° C和25 ° C下不同。然而，相当大比例的细胞是生化相同的，因为人口heterogeneity.Conclusions：在这项研究中提出的光谱方法允许在单个浮游植物细胞中的大分子的定量。这种方法表明，人口异质性最有可能确保备份的非驯化细胞，可以迅速利用新的有利的生态位。这一发现可能对浮游植物种群生态学产生重要影响，并表明“平均细胞”概念可能会大大限制我们对水生生态系统中种群动态和生物地球化学循环的理解。
Background: Technical limitations regarding bulk analysis of phytoplankton biomass limit our comprehension of carbon fluxes in natural populations and, therefore, of carbon, nutrients and energy cycling in aquatic ecosystems. In this study, we took advantage of Synchrotron FTIR micro-spectroscopy and the partial least square regression (PLSr) algorithm to simultaneously quantify the protein, lipid and carbohydrate content at the single-cell level in a mock phytoplankton community (composed by a cyanobacterium, a green-alga and a diatom) grown at two temperatures (15 degrees C and 25 degrees C).Results: The PLSr models generated to quantify cell macromolecules presented high quality fit (R-2 >= 0.90) and low error of prediction (RMSEP 2-6% of dry weight). The regression coefficients revealed that the prediction of each macromolecule was not exclusively dependent on spectral features corresponding to that compound, but rather on all major macromolecular pools, reflecting adjustments in the overall cell carbon balance.The single-cell analysis, studied by means of Kernel density estimators, showed that the modes of density distribution of macromolecules were different at 15 degrees C and 25 degrees C. However, a substantial proportion of cells was biochemically identical at the two temperatures because of population heterogeneity.Conclusions: The spectroscopic approach presented in this study allows the quantification of macromolecules in single phytoplankton cells. This method showed that population heterogeneity most likely ensures a backup of non-acclimated cells that may rapidly exploit new favourable niches. This finding may have important consequences for the ecology of phytoplankton populations and shows that the "average cell" concept might substantially limit our comprehension of population dynamics and biogeochemical cycles in aquatic ecosystems.