Crossbands of Caulobacter crescentus Stalks serve as Indicators of Cell Age

Staley, James T.; Jordan, T. L.

doi:10.1038/246155a0

Cited by 37 publications

(32 citation statements)

References 7 publications

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“…Therefore it appears that the stalk is formed only partially in the first bacterial generation starting from the swarmer cell. This interpretation is supported by a previous observation that the stalk formation is a slow process and requires several bacterial generations to attain its maximal length [4,11]. The unique features of Caulobacter morphogenesis are an obligatory transition of the swarmer cell to the stalked cell before cell division and the expression of the polar structures (a stalk, a single flagellum and pili) at the specific time of the cell cycle [5,6,8,12].…”

Section: Methodssupporting

confidence: 64%

Synchronous Cell Differentiation in Caulobacter crescentus

Iba

Fukuda

Okada

1975

Japanese Journal of Microbiology

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The growth of a stalked bacterium, Caulobacter crescentus, has been synchronized easily and reproducibly by a new method. When this bacterium is grown to a late log phase in nutrient broth at 30 C with aeration, swarmer cells are accumulated in the culture to 80% of the whole cell population. When this culture is inoculated into fresh pre-warmed broth at twentyfold dilution, it immediately initiates synchronous cell growth. Simultaneously, synchronous cell differentiation is monitored by the susceptibility of the cells to RNA phage infection. The swarmer cells accumulated in the late log phase of growth possess nearly the same susceptibility to RNA phage infection as those in the early log phase of growth while RNA phage-adsorbing capacity is lower in such swarmer cells. It is suggested that the swarmer cells accumulated in the late log phase of growth have lost some pili.

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Section: Methodssupporting

confidence: 64%

Synchronous Cell Differentiation in Caulobacter crescentus

Iba

Fukuda

Okada

1975

Japanese Journal of Microbiology

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“…3, arrowhead c). The number of crossbands is variable, and it is uncertain whether the number depends on stalk length, stalk age, or neither (30,33). The distance between crossbands is also variable.…”

Section: Resultsmentioning

confidence: 99%

A Caulobacter gene involved in polar morphogenesis

et al. 1990

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At specific times in the cell cycle, the bacterium Caulobacter crescentus assembles two major polar organelles, the flagellum and the stalk. Previous studies have shown that flbT mutants overproduce flagellins and are unable to form chemotaxis swarm rings. In this paper, we report alterations in both the stalk and the flagellar structure that result from a mutation in the flagellar geneflbT. Mutant strains produce some stalks that have a flagellum, produce some stalks that have an extra lobe protruding from their sides, have filaments lacking the 29-kilodalton flagellin, and produce several unusual cell types, including ifiamentous cells as well as predivisional cells with two stalks and predivisional cells with no stalk at all. We propose that flagellated stalks arise as a consequence of a failure to eject the flagellum at the correct time in the cell cycle and that the extra stalk lobe is due to a second site for the initiation of stalk biogenesis. Thus, a step in the pathway that establishes the characteristic asymmetry of the C. crescentus cell appears to be disrupted in flbT mutants. We have also identified a new structural feature at the flagellated pole and the tip of the stalk: the 10-nm polar particle. The polar particles appear as a cluster of -1 to 10 stain-excluding rings, visible in electron micrographs of negatively stained wild-type cells. This structure is absent at the flagellar pole but not in the stalks of flbT mutant predivisional cells.Caulobacter crescentus is a bacterium with a developmentally regulated cell cycle (18,26). During the course of development, the cell morphology undergoes a series of changes. The most striking of these changes is the appearance of two structures on the cell surface, namely, the flagellum and the stalk. The flagellum is composed of an extracellular propeller (the hook-filament complex) and a membrane-bound structure, called the basal body, believed to be part of the motor that rotates the hook-filament complex and thereby allows * Corresponding author. the cell to swim (for a review, see reference 16). The flagellum always forms at one pole of the cell at a specific time in the cell cycle. Later in the cell cycle, the extracellular portion of the flagellum, the hook-filament complex, is ejected into the culture medium (27,32

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“…Staley and Jordan (32) concluded that the addition of a band occurred during or shortly after cell division. The statistical analysis reported here implies even more narrowly that in reproducing populations, the new band is added while the cell is constricted.…”

Section: Discussionmentioning

confidence: 99%

“…On the basis of studies of developing swarmer populations and of stalked cells growing attached to a solid substrate through 19 generations, Staley and Jordan (32) proposed that the stalk bands were added at regular intervals during stalk outgrowth, with one band appearing during each reproductive cycle completed by the cell. The bands would then serve as indicators of cell age by reflecting the number of cell cycles that had been completed by a cell since the generation in which the cell was a swarmer.…”

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confidence: 99%

Caulobacter and Asticcacaulis stalk bands as indicators of stalk age

Poindexter

Staley

1996

J Bacteriol

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The prosthecae (stalks) of dimorphic caulobacters of the genera Caulobacter and Asticcacaulis are distinguished among such appendages by the presence of disk-like components known as stalk bands. Whether bands are added to a cell's stalk(s) as a regular event coordinated with the cell's reproductive cycle has not been settled by previous studies. Analysis of the frequency of stalks with i, i ؉ 1, i ؉ 2, etc. bands among more than 7,000 stalks of Caulobacter crescentus revealed that in finite (batch) cultures (in which all offspring accumulate), the proportion of stalks with i ؉ 1 bands was regularly 50% of the proportion of stalks with i bands. This implied that the number of bands correlated with the number of reproductive cycles completed by a stalked cell. In chemostat-maintained perpetual cultures, the proportion was greater than 50% because stalked cells, with their shorter reproductive cycle times, contributed a larger proportion of offspring to the steady-state population than did their swarmer siblings. In Asticcacaulis biprosthecum cells, which bear twin prosthecae, the twins on a typical cell possessed the same number of bands. For both genera, stalk bands provide a unique morphological feature that could be employed in an assessment of age distribution and reproductive dynamics within natural populations of these caulobacters.Stalked bacteria that divide asymmetrically and produce one motile and one stalked cell at each reproductive event were first described by Henrici and Johnson (8) on the basis of observations of cells attached to glass slides that had been submerged in a freshwater lake. Leifson (12) later detected a single flagellum at the pole of the motile cell by light microscopy of stained cells, and Houwink (9) provided electron micrographs of dividing cells, each with two distinctly different appendages, the stalk at one pole and the flagellum at the other; Houwink also detected the presence of bands in Caulobacter stalks. Bands are visible within ultrathin sections of both Caulobacter and Asticcacaulis stalks (15,17,23,25); they are structurally integrated into the concentric layers of membranes and peptidoglycan of the stalk and are disorganized by lysozyme. Isolated bands are seen as disks composed of concentric rings (5,10,27). A similar disk of rings has been described by Coulton and Murray (1, 2) as the structure embedded in the outer membrane of Aquaspirillum cells through which the flagellum emerges from the cell surface.The initial stages of stalk development can be studied in synchronously developing swarmer populations, although synchrony deteriorates after the first generation (4, 6, 29, 33). On the basis of studies of developing swarmer populations and of stalked cells growing attached to a solid substrate through 19 generations, Staley and Jordan (32) proposed that the stalk bands were added at regular intervals during stalk outgrowth, with one band appearing during each reproductive cycle completed by the cell. The bands would then serve as indicators of cell age by reflect...

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Crossbands of Caulobacter crescentus Stalks serve as Indicators of Cell Age

Cited by 37 publications

References 7 publications

Synchronous Cell Differentiation in Caulobacter crescentus

Synchronous Cell Differentiation in Caulobacter crescentus

A Caulobacter gene involved in polar morphogenesis

Caulobacter and Asticcacaulis stalk bands as indicators of stalk age

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