Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan.
Anal Chem. 2013 Aug 6;85(15):7295-301. doi: 10.1021/ac401188f. Epub 2013 Jul 10.
Aggregation of bacterial populations substantially influences their characteristic properties and functions compared with the planktonic counterpart. It is also involved in the initial stages of biofilm development. Many studies have revealed important roles of bacterial aggregation in microbial production and biodegradation. Nevertheless, mechanistic understanding of bacterial aggregation in vivo and at the molecular level is far from complete. Here, we present a noninvasive, label-free Raman microspectroscopic approach to investigate the aggregation and biofilm development of the biotechnologically important Rhodococcus sp. SD-74. We found that the concentration of intracellular carotenoids increases more than 3-fold within 1 week as the biofilm develops. Raman imaging experiments confirmed that the carotenoid accumulation occurs throughout the Rhodococcus sp. SD-74 biofilm. The correlation between the carotenoid Raman intensities and biofilm development found in the present study provides a new means for quantitative, molecular-level assessment of the level of biofilm development, which is not possible with dye staining assay or electron microscopy. Moreover, our results suggest that microbial production of carotenoids in pigmented bacteria such as Rhodococcus sp. SD-74 may potentially be controlled via bacterial aggregation and biofilm formation.
与浮游态相比，细菌聚集体显著影响其特征性质和功能。它还参与生物膜发展的初始阶段。许多研究揭示了细菌聚集在微生物生产和生物降解中的重要作用。然而，细菌在体内和分子水平上聚集的机制理解还远远不够。在这里，我们提出了一种非侵入性、无标记的喇曼微光谱方法来研究生物技术上重要的红球菌 sp. SD-74 的聚集和生物膜发展。我们发现，在生物膜形成的 1 周内，细胞内类胡萝卜素的浓度增加了 3 倍以上。喇曼成像实验证实，类胡萝卜素的积累发生在整个 Rhodococcus sp. SD-74 生物膜中。本研究中发现的类胡萝卜素喇曼强度与生物膜发展之间的相关性为定量、分子水平评估生物膜发展水平提供了一种新的手段，这是染料染色测定或电子显微镜无法实现的。此外，我们的结果表明，在 Rhodococcus sp. SD-74 等色素细菌中微生物生产类胡萝卜素可能可以通过细菌聚集和生物膜形成来控制。
