Linear Cell Growth in Escherichia coli

Abstract

Growth was studied in synchronous cultures of Escherichia coli, using three strains and several rates of cell division. Synchrony was obtained by the Mitchison-Vincent technique. Controls gave no discernible perturbation in growth or rate of cell division. In all cases, mean cell volumes increased linearly (rather than exponentially) during the cycle except possibly for a small period near the end of the cycle. Linear volume growth occurred in synchronous cultures established from cells of different sizes, and also for the first volume doubling of cells prevented from division by a shift up to a more rapid growth rate. As a model for linear kinetics, it is suggested that linear growth represents constant uptake of all major nutrient factors during the cycle, and that constant uptake in turn is established by the presence of a constant number of functional binding or accumulation sites for each growth factor during linear growth of the cell.

Variation in precursor pool size during the division cycle of Escherichia coli: further evidence for linear cell growth

“…When increase in cell mass was determined under steady-state growth conditions, as the product of cell volume and buoyant density, the results supported a linear growth model (13). A major difficulty in discriminating among the three models is that they predict only minor differences in cell size throughout the cycle; for example, maximum deviations in cell size predicted by exponential and linear cell growth models are less than 6% (9). Nevertheless, although growth patterns do not differ markedly for exponential, linear, and bilinear cell growth, these models have very different implications for the modes and mechanisms of the regulation of growth during the division cycle.…”

Scaling laws governing stochastic growth and division of single bacterial cells

“…There is evidence that the growth laws for various microorganisms under favorable conditions are exponential (14,(22)(23)(24)(25). However, both linear and exponential growth laws have been previously proposed (26)(27)(28)(29), and it is estimated that a measurement precision of 6% is required to discriminate between these functional forms for cells that double in size during each division period (5). This precision is difficult to achieve in typical single-cell microscopy studies because cell division leads to rapid crowding of the field of view (30).…”

A size-structured model of bacterial growth and reproduction

“…However, the question of whether the cell growth rate can be generally expected to be size-proportional appears to have still not been settled. Based on an extensive set of experiments performed with Escherichia coli and other bacteria, Kubitschek [12][13][14][15] argues that the rate of the increase in size of these bacteria is constant throughout most of the cell cycle. On the other hand, Cooper [5] strongly takes the position that the rate of cell growth is indeed size proportional.…”