Direct Visualization of Nano-Spinning Process of Cellulose Produced by Acetobacter Xyliman

本文试图直接观察由木醋杆菌生产的纤维素的纳米纺丝过程。所得结果如下：1。利用视频显微镜系统观察了活菌制备的宽约50 nm的带状纤维素组件的纳米纺丝过程。该系统由差干涉对比显微镜、CCD摄像机、图像处理器、视频监视器和盒式录像机组成。粗糙菌落的纺丝速度为3.4 μm/min，光滑菌落的纺丝速度为2.4 μm/min。这种纺丝速度的差异可能是两种菌落产生的纤维素高阶结构不同的原因之一。在4℃条件下，用从xyactobacter ATCC 23769分离的光滑菌落制备了由许多条组成的致密和粗糙的带状纤维素组合，而在28℃条件下，用相同菌落制备了带状组合。2 .在选择区电子衍射（ED）实验中，密集的组装产生了与纤维素II型晶体对应的结晶反射，而在相同的ED条件下，粗糙的组装没有产生结晶反射。未干燥的带状组件在液态丙烷（-179℃）中快速淬火，并通过冷冻转移引入TEM柱。我们尝试用低温透射电镜（JEOL JEM-4000SFX在400kV下工作）拍摄带状组件的图像。然而，嵌入组件的玻璃冰太厚，电子束无法穿透样品。有必要尽量减少样品中水的含量。进一步调查正在进行中。

In this paper we tried to directly observe nano-spinning process of cellulose produced by Acetobacter xylinum. The results obtained are as given below.1. Nano-spinning process of the ribbon-like cellulose assembly with a width of about 50 nm produced by a living bacterium was visualized by a video microscopy system. This system is composed of a differential interference contrast microscope, a CCD camera, an image processor, a video monitor, and a videocassette recorder. The spinning speed measured for a bacterium from rough colony was 3.4 μm/min, and that from smooth colony was 2.4 μm/min. This difference in spinning speed may be one of the reasons why high-order structures of cellulose produced by two types of colonies are different.2. Dense and coarse band-like cellulose assemblies which consist of many strands were produced at 4 ℃, using smooth colonies isolated from Acetobacter xylinum ATCC 23769, whereas ribbon assemblies were produced by the same colonies at 28 ℃. The dense assembly gave crystalline reflections corresponding to the cellulose II type crystal in the selected-area electron diffraction (ED) experiment, while the coarse assembly did not give crystalline reflections under the same ED condition.3. Never-dried ribbon assemblies were rapidly quenched in liquid propane (-179 ℃) and introduced into a TEM column by cryo-transfer. We tried to take images of ribbon assemblies with a cryo-TEM (JEOL JEM-4000SFX operated at 400kV). However, the vitreous ice embedding the assemblies was so thick that electron beams did not penetrate the samples. It is necessary to minimize the content of water in the samples. Further investigation is in progress.