Jayathilake Pahala G, Jana Saikat, Rushton Steve, Swailes David, Bridgens Ben, Curtis Tom, Chen Jinju
School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom.
School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
Front Microbiol. 2017 Sep 27;8:1865. doi: 10.3389/fmicb.2017.01865. eCollection 2017.
The production of extracellular polymeric substance (EPS) is important for the survival of biofilms. However, EPS production is costly for bacteria and the bacterial strains that produce EPS (EPS+) grow in the same environment as non-producers (EPS-) leading to competition between these strains for nutrients and space. The outcome of this competition is likely to be dependent on factors such as initial attachment, EPS production rate, ambient nutrient levels and quorum sensing. We use an Individual-based Model (IbM) to study the competition between EPS+ and EPS- strains by varying the nature of initial colonizers which can either be in the form of single cells or multicellular aggregates. The microbes with EPS+ characteristics obtain a competitive advantage if they initially colonize the surface as smaller aggregates and are widely spread-out between the cells of EPS-, when both are deposited on the substratum. Furthermore, the results show that quorum sensing-regulated EPS production may significantly reduce the fitness of EPS producers when they initially deposit as aggregates. The results provide insights into how the distribution of bacterial aggregates during initial colonization could be a deciding factor in the competition among different strains in biofilms.
胞外聚合物（EPS）的产生对生物膜的存活至关重要。然而，EPS的产生对细菌来说成本高昂，并且产生EPS的细菌菌株（EPS+）与不产生EPS的菌株（EPS-）在相同环境中生长，导致这些菌株之间对营养和空间的竞争。这种竞争的结果可能取决于诸如初始附着、EPS产生速率、环境营养水平和群体感应等因素。我们使用基于个体的模型（IbM），通过改变初始定殖者的性质来研究EPS+和EPS-菌株之间的竞争，初始定殖者可以是单细胞形式或多细胞聚集体形式。如果具有EPS+特征的微生物最初以较小的聚集体形式定殖在表面，并且当两者都沉积在基质上时在EPS-的细胞之间广泛分布，它们就会获得竞争优势。此外，结果表明，群体感应调节的EPS产生在最初以聚集体形式沉积时可能会显著降低EPS生产者的适应性。这些结果为初始定殖期间细菌聚集体的分布如何可能成为生物膜中不同菌株间竞争的决定性因素提供了见解。
