Jones Joseph F, Velegol Darrell
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Colloids Surf B Biointerfaces. 2006 Jun 1;50(1):66-71. doi: 10.1016/j.colsurfb.2006.04.004. Epub 2006 Apr 27.
Rod-shaped Escherichia coli K12:D21 bacteria were previously found to adhere by their ends (poles) [J.F. Jones, J.D. Feick, D. Imoudu, N. Chukwumah, M. Vigeant, D. Velegol, Appl. Environ. Microbiol. 69 (2003) 6515.]. In the current study we used a Nd:YAG 1064 nm laser trap to quantify the fraction of adherent bacteria and the time scale for the adhesion to occur. For the E. coli studied, 15.9+/-3.4% of the bacteria adhered when presented end-on for 15s to a cleaned glass surface that was not treated for specific interactions. These bacteria were found to adhere either instantaneously (approximately <1s) or not at all, and the adhesion was shown to be independent of power (force) of the laser trap. Additionally, for a given bacterium, either 0 or 1 ends were adhesive, never both ends. It is hypothesized that the end-on adhesion of D21 is related to bacterial polarity that dynamically results from the division process. We studied the reattachment of cells after adhesion and subsequent removal, finding that most bacteria reattach, some at least five times. However, a small fraction of D21 did not reattach after the first removal. Bacterial cells with observable division planes were tested for end-on adhesion; none of the 18 cells studied adhered by either end. On the other hand, we examined 50 daughter cells immediately after division, and four of the cells were adhesive. End-on adhesion is shown to be an important initial adhesion strategy for the E. coli strain via a single end with adhesion occurring instantaneously. Knowledge about adherent nanodomains (here, on one end) on bacteria will lead to better predictions of sticking coefficients and bacteria transport through porous media.
先前发现杆状大肠杆菌K12:D21通过其末端（极）附着[J.F.琼斯、J.D.费克、D.伊莫杜、N.丘库马、M.维让、D.韦勒戈尔，《应用与环境微生物学》69(2003)6515]。在当前研究中，我们使用Nd:YAG 1064纳米激光阱来量化附着细菌的比例以及发生附着的时间尺度。对于所研究的大肠杆菌，当将其末端对着未经过特定相互作用处理的清洁玻璃表面放置15秒时，15.9±3.4%的细菌发生了附着。发现这些细菌要么瞬间（约<1秒）附着，要么根本不附着，并且附着显示与激光阱的功率（力）无关。此外，对于给定的细菌，要么0个末端具有粘附性，要么1个末端具有粘附性，从未有两个末端都具有粘附性的情况。据推测，D21的末端附着与细菌极性有关，而细菌极性是由分裂过程动态产生的。我们研究了细胞在附着并随后被移除后的重新附着情况，发现大多数细菌会重新附着，有些至少重新附着五次。然而，一小部分D21在首次移除后没有重新附着。对具有可观察到分裂平面的细菌细胞进行了末端附着测试；所研究的18个细胞中没有一个通过任何一端附着。另一方面，我们检查了刚分裂后的50个子代细胞，其中有4个细胞具有粘附性。末端附着被证明是大肠杆菌菌株一种重要的初始附着策略，通过单个末端瞬间发生附着。了解细菌上的附着纳米域（此处为一端）将有助于更好地预测粘附系数以及细菌在多孔介质中的传输。
