Determining Effect of Growth Medium on the Shape and Position of Daughter Chromosomes and on Sporulation in Bacillus subtilis

Dawes, Ian W.; Kay, D.; Mandelstam, J.

doi:10.1038/230567a0

Cited by 44 publications

(28 citation statements)

References 8 publications

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“…As mentioned above, virtually all cell pairs observed (84%) showed similar states of development. The synchronization of sporulation in sister cells has been reported previously but in relation to relatively late events, from septation onwards (9). In this study, we found strong synchronization even when examining early, relatively transient events.…”

Section: Discussionsupporting

confidence: 57%

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Characterization of cell cycle events during the onset of sporulation in Bacillus subtilis

Hauser

Errington

1995

J Bacteriol

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To elucidate the process of asymmetric division during sporulation of Bacillus subtilis, we have measured changes in cell cycle parameters during the transition from vegetative growth to sporulation. Because the propensity of B. subtilis to grow in chains of cells precludes the use of automated cell-scanning devices, we have developed a fluorescence microscopic method for analyzing cell cycle parameters in individual cells. From the results obtained, and measurements of DNA replication fork elongation rates and the escape time of sporulation from the inhibition of DNA replication, we have derived a detailed time scale for the early morphological events of sporulation which is mainly consistent with the cell cycle changes expected following nutritional downshift. The previously postulated sensitive stage in the DNA replication cycle, beyond which the cell is unable to sporulate without a new cell cycle, could represent a point in the division cycle at which the starved cell cannot avoid attaining the initiation mass for DNA replication and thus embarking on another round of the cell cycle. The final cell cycle event, formation of the asymmetric spore septum, occurs at about the time in the cell cycle at which the uninduced cell would have divided centrally, in keeping with the view that spore septation is a modified version of vegetative division.Under starvation conditions, Bacillus subtilis undergoes a differentiation process that culminates with the release of a dormant endospore. The first overt morphological event in this process is the formation of a polar division septum positioned quite differently from the centrally located septum of the vegetative cell. Asymmetric septation generates two compartments of unequal size, a large one, the mother cell, and a smaller one, the prespore. The morphology of cells during the asymmetric division process (20, 21) and the common requirements for cell division genes, such as ftsZ (4), divIC (27), and divIB (3), suggest that spore septum formation is a modified form of vegetative division.Although a great deal is known about the nature of the nutritional signals controlling the switch from vegetative growth to sporulation (22) and about the changes in transcription that accompany and direct the differentiation of prespore and mother cell (15), little is known about how the cell cycle is modified at the onset of sporulation. The starting material for sporulation is apparently a cell containing two fully replicated chromosomes, one destined for the spore and the other remaining in the mother cell (2,19,37,41,46). Consequently, when sporulation is initiated after a period of relatively rapid growth and thus dichotomous replication, the cell must undergo a complex transition to a state in which two completed, nonreplicating chromosomes are present. In order for this to occur, it seems likely that ongoing rounds of replication must be completed and new rounds avoided, but how this reorganization of the cell cycle is achieved has not been elucidated.Two lines of evidence, obt...

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Section: Discussionsupporting

confidence: 57%

“…Firstly, pairs of sister cells tend to be at the same developmental stage of sporulation (9), suggesting that they initiated sporulation simultaneously. This could obviously be a consequence of sister cells being synchronized with respect to the cell cycle, having been the products of the same division.…”

mentioning

confidence: 99%

Characterization of cell cycle events during the onset of sporulation in Bacillus subtilis

Hauser

Errington

1995

J Bacteriol

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“…9). Previous work has shown that sporulation can only occur when the chromosome is in a particular stage of replication (31,32). It will be interesting to see the importance of the replication state on the final bifurcation of the differentiation pathways.…”

Section: Discussionmentioning

confidence: 99%

Bet-hedging and epigenetic inheritance in bacterial cell development

Veening

Stewart

Berngruber

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

309

330

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Upon nutritional limitation, the bacterium Bacillus subtilis has the capability to enter the irreversible process of sporulation. This developmental process is bistable, and only a subpopulation of cells actually differentiates into endospores. Why a cell decides to sporulate or not to do so is poorly understood. Here, through the use of time-lapse microscopy, we follow the growth, division, and differentiation of individual cells to identify elements of cell history and ancestry that could affect this decision process. These analyses show that during microcolony development, B. subtilis uses a bet-hedging strategy whereby some cells sporulate while others use alternative metabolites to continue growth, providing the latter subpopulation with a reproductive advantage. We demonstrate that B. subtilis is subject to aging. Nevertheless, the age of the cell plays no role in the decision of its fate. However, the physiological state of the cell's ancestor (more than two generations removed) does affect the outcome of cellular differentiation. We show that this epigenetic inheritance is based on positive feedback within the sporulation phosphorelay. The extended intergenerational ''memory'' caused by this autostimulatory network may be important for the development of multicellular structures such as fruiting bodies and biofilms.aging ͉ Bacillus subtilis ͉ bistability ͉ sporulation

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“…They showed that there is a sensitive period in the cell cycle during which sporulation can be initiated. Once cells pass this window of opportunity, they must traverse another cycle before being capable of initiation, irrespective of their nutritional status (Dawes et al, 1971;Dunn et al, 1978;. For many years the nature of the regulatory mechanisms responsible for coupling of the initiation of sporulation with cell cycle progression remained unclear.…”

Section: Asymmetry and The Determination Of Cell Fatementioning

confidence: 99%

From spores to antibiotics via the cell cycle

Errington

2010

Microbiology

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Spore formation in Bacillus subtilis is a superb experimental system with which to study some of the most fundamental problems of cellular development and differentiation. Work begun in the 1980s and ongoing today has led to an impressive understanding of the temporal and spatial regulation of sporulation, and the functions of many of the several hundred genes involved. Early in sporulation the cells divide in an unusual asymmetrical manner, to produce a small prespore cell and a much larger mother cell. Aside from developmental biology, this modified division has turned out to be a powerful system for investigation of cell cycle mechanisms, including the components of the division machine, how the machine is correctly positioned in the cell, and how division is coordinated with replication and segregation of the chromosome. Insights into these fundamental mechanisms have provided opportunities for the discovery and development of novel antibiotics. This review summarizes how the bacterial cell cycle field has developed over the last 20 or so years, focusing on opportunities emerging from the B. subtilis system.

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Determining Effect of Growth Medium on the Shape and Position of Daughter Chromosomes and on Sporulation in Bacillus subtilis

Cited by 44 publications

References 8 publications

Characterization of cell cycle events during the onset of sporulation in Bacillus subtilis

Characterization of cell cycle events during the onset of sporulation in Bacillus subtilis

Bet-hedging and epigenetic inheritance in bacterial cell development

From spores to antibiotics via the cell cycle

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