Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary.
Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, H-6726 Szeged, Hungary.
Cells. 2023 May 19;12(10):1430. doi: 10.3390/cells12101430.
The growth of bacterial populations has been described as a dynamic process of continuous reproduction and cell death. However, this is far from the reality. In a well fed, growing bacterial population, the stationary phase inevitably occurs, and it is not due to accumulated toxins or cell death. A population spends the most time in the stationary phase, where the phenotype of the cells alters from the proliferating ones, and only the colony forming unit (CFU) decreases after a while, not the total cell concentration. A bacterial population can be considered as a virtual tissue as a result of a specific differentiation process, in which the exponential-phase cells develop to stationary-phase cells and eventually reach the unculturable form. The richness of the nutrient had no effect on growth rate or on stationary cell density. The generation time seems not to be a constant value, but it depended on the concentration of the starter cultures. Inoculations with serial dilutions of stationary populations reveal a so-called minimal stationary cell concentration (MSCC) point, up to which the cell concentrations remain constant upon dilutions; that seems to be universal among unicellular organisms.
细菌群体的生长被描述为一个不断繁殖和细胞死亡的动态过程。然而，这与现实相去甚远。在营养充足、生长中的细菌群体中，不可避免地会进入静止期，而这并不是由于积累的毒素或细胞死亡造成的。群体在静止期花费的时间最多，此时细胞的表型从增殖型转变，并且只有一段时间后菌落形成单位（CFU）减少，而不是总细胞浓度。由于特定的分化过程，细菌群体可以被视为一种虚拟组织，其中指数期细胞发育为静止期细胞，最终达到不可培养的形式。营养物质的丰富度对生长速度或静止细胞密度没有影响。世代时间似乎不是一个常数，而是取决于起始培养物的浓度。用静止期群体的连续稀释液接种揭示了所谓的最小静止细胞浓度（MSCC）点，在该点以下，细胞浓度在稀释时保持不变；这似乎在单细胞生物中是普遍存在的。
