Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115.
Microbiol Spectr. 2015 Apr;3(2):MB-0002-2014. doi: 10.1128/microbiolspec.MB-0002-2014.
The dense aggregation of cells on a surface, as seen in biofilms, inevitably results in both environmental and cellular heterogeneity. For example, nutrient gradients can trigger cells to differentiate into various phenotypic states. Not only do cells adapt physiologically to the local environmental conditions, but they also differentiate into cell types that interact with each other. This allows for task differentiation and, hence, the division of labor. In this article, we focus on cell differentiation and the division of labor in three bacterial species: Myxococcus xanthus, Bacillus subtilis, and Pseudomonas aeruginosa. During biofilm formation each of these species differentiates into distinct cell types, in some cases leading to cooperative interactions. The division of labor and the cooperative interactions between cell types are assumed to yield an emergent ecological benefit. Yet in most cases the ecological benefits have yet to be elucidated. A notable exception is M. xanthus, in which cell differentiation within fruiting bodies facilitates the dispersal of spores. We argue that the ecological benefits of the division of labor might best be understood when we consider the dynamic nature of both biofilm formation and degradation.
细胞在表面的密集聚集，如生物膜中所见，不可避免地导致环境和细胞异质性。例如，营养梯度可以促使细胞分化为各种表型状态。细胞不仅在生理上适应局部环境条件，还分化为相互作用的细胞类型。这允许任务分化，从而分工。在本文中，我们专注于三种细菌物种中的细胞分化和分工：粘细菌、枯草芽孢杆菌和铜绿假单胞菌。在生物膜形成过程中，这些物种中的每一种都分化为不同的细胞类型，在某些情况下导致合作相互作用。细胞类型之间的分工和合作相互作用据说是为了产生一个新兴的生态效益。然而，在大多数情况下，生态效益尚未阐明。一个值得注意的例外是粘细菌，在其生殖体中细胞分化促进孢子的分散。我们认为，当我们考虑生物膜形成和降解的动态性质时，分工的生态效益可能是最好理解的。
