Kuśmierska Anna, Spiers Andrew J
School of Science, Engineering and Technology, Abertay University, Bell Street, Dundee DD1 1HG, UK; Department of Industrial Microbiology and Biotechnology, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland.
School of Science, Engineering and Technology, Abertay University, Bell Street, Dundee DD1 1HG, UK.
Int J Evol Biol. 2016;2016:4846565. doi: 10.1155/2016/4846565. Epub 2016 Dec 22.
Adaptive radiation in bacteria has been investigated using Wrinkly Spreaders (WS), a morphotype which colonises the air-liquid (A-L) interface of static microcosms by biofilm formation with a significant fitness advantage over competitors growing lower down in the O-limited liquid column. Here, we investigate several environmental parameters which impact the ecological opportunity that the Wrinkly Spreaders exploit in this model system. Manipulation of surface area/volume ratios suggests that the size of the WS niche was not as important as the ability to dominate the A-L interface and restrict competitor growth. The value of this niche to the Wrinkly Spreaders, as determined by competitive fitness assays, was found to increase as O flux to the A-L interface was reduced, confirming that competition for O was the main driver of WS fitness. The effect of O on fitness was also found to be dependent on the availability of nutrients, reflecting the need to take up both for optimal growth. Finally, the meniscus trap, a high-O region formed by the interaction of the A-L interface with the vial walls, was also important for fitness during the early stages of biofilm formation. These findings reveal the complexity of this seemingly simple model system and illustrate how changes in environmental physicality alter ecological opportunity and the fitness of the adaptive morphotype.
利用皱波扩展菌（WS）对细菌的适应性辐射进行了研究，WS是一种形态类型，通过形成生物膜在静态微观世界的气液（A-L）界面定殖，相对于在氧气有限的液柱中较低位置生长的竞争者具有显著的适应性优势。在此，我们研究了几个影响皱波扩展菌在该模型系统中所利用的生态机会的环境参数。表面积/体积比的操控表明，WS生态位的大小不如占据A-L界面并限制竞争者生长的能力重要。通过竞争适应性测定确定，随着进入A-L界面的氧气通量减少，该生态位对皱波扩展菌的价值增加，这证实了对氧气的竞争是WS适应性的主要驱动因素。还发现氧气对适应性的影响取决于营养物质的可用性，这反映了为实现最佳生长同时摄取两者的必要性。最后，弯月面陷阱是由A-L界面与小瓶壁相互作用形成的高氧区域，在生物膜形成的早期阶段对适应性也很重要。这些发现揭示了这个看似简单的模型系统的复杂性，并说明了环境物理特性的变化如何改变生态机会和适应性形态类型的适应性。
