Capsular polysaccharide production from Zunongwangia profunda SM-A87 monitored at single cell level by atomic force microscopy
Capsular polysaccharide production from Zunongwangia profunda SM-A87 monitored at single cell level by atomic force microscopy
复制标题
通过原子力显微镜在单细胞水平监测 Zunongwangia profunda SM-A87 荚膜多糖的产生
DOI：
10.1016/j.dsr2.2017.08.009
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发表时间：
2018-09-01
影响因子：
3
通讯作者：
Zhang, Yu-Zhong
中科院分区：
文献类型：
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作者：
Li, Kang;Zhao, Long-Sheng;Zhang, Yu-Zhong
许多海洋细菌分泌多糖作为生长策略，结合痕量金属，粘附于固体表面，并在不利条件下生存。因此，由于它们的生物学作用以及潜在的工业应用，它们吸引了广泛的研究兴趣。人们对多糖产生菌的生长动力学进行了大量的研究。过去通常研究生长过程中每个细胞的平均多糖产量。然而，以往的研究大多是在群体水平上进行的，在单细胞水平上的研究并不多见。原子力显微镜（AFM）是研究单个微生物及其胞外多糖的有力工具。利用原子力显微镜（AFM）研究了从深海沉积物中分离到的一株产荚膜多糖（CPS）细菌Zunongwangia profunda SM-A87的生长动力学和CPS产量。Z. profunda SM-A87在10 ℃下表现出缓慢的生长速率，这低于最佳生长温度（30 ℃）。但在10 ℃下的CPS产量远远高于30 ℃。AFM的单细胞成像在两种温度下都显示出杆状细胞形态，但在10 ℃时有时可以观察到丝状细菌。观察到细菌细胞周围的CPS，并且多糖的原纤维缠结成网络。随着培养时间的延长，多糖纤维的长度和胶囊的直径增加。计算两种温度下细菌细胞和每个细胞周围的荚膜多糖的平均体积。单个细菌细胞的平均体积为0.2-0.3 μ m（3），在指数期增加，在稳定期略有下降，但在细菌生长过程中，单个细胞产生的CPS的平均体积增加。CPS产量在10摄氏度的稳定期增加到0.097 +/- 0.051 μ m（3）/细胞，这大于在30摄氏度的产量（0.055 +/- 0.013 μ m（3）/细胞）。我们报告了一种新的方法估计平均细菌多糖产量与原子力显微镜。由于海洋沉积物中含有大量的产多糖细菌，该方法对研究深海产多糖细菌的生物学和生态学作用具有潜在的意义。
Polysaccharides are secreted by many marine bacteria as a strategy for growth, binding trace metals, adhering to solid surfaces, and to survive adverse conditions. Therefore, they have attracted extensive research interest due to their biological roles as well as potential industrial application. Many works have been carried out to study the growth dynamics of polysaccharides producing bacteria. Average polysaccharide production per cell during growth were usually studied in the past. However, most previous works were carried out at the population level, and the research at a single cell level was rare. Atomic force microscopy (AFM) is a powerful tool in studying single microorganisms and their extracellular polysaccharides. Here we investigated the growth dynamics and capsular polysaccharide (CPS) production of a CPS producing bacterium Zunongwangia profunda SM-A87 isolated from deep-sea sediments with AFM. Z. profunda SM-A87 exhibited slow growth rates at 10 degrees C, which was lower than at optimum growth temperature (30 degrees C). But the CPS production at 10 degrees C was much higher than that at 30 degrees C. Single cell imaging with AFM revealed rod like cell morphology at both temperatures, but filamentous bacteria could sometimes be noticed at 10 degrees C. The CPSs surrounding bacterial cells were observed, and the fibrils of polysaccharides entangled into networks. The diameter of the capsules and the length of the polysaccharides fibrils increased as cultivation time increased. The average volume of the bacterial cells and capsular polysaccharides surrounding each cell at both temperatures were calculated. The average volume of a single bacterial cell was 0.2-0.3 mu m(3), and it increased in exponential phase and slightly decreased in stationary phase, but the average volume of CPS produced by single cells increased during bacterial growth. CPS production increased to 0.097 +/- 0.051 mu m(3) per cell at 10 degrees C in stationary phase, which is larger than that produced at 30 degrees C (0.055 +/- 0.013 mu m(3) per cell). We report a novel method of estimating the average bacterial polysaccharide production with AFM. Since polysaccharides-producing bacteria are abundant in marine sediments, this method is potentially useful for studying the biological and ecological role of polysaccharides-producing bacteria from the deep sea in the future.