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A ten-year search for synchronous cells: obstacles, solutions, and practical applications.

Helmstetter CE - Front Microbiol (2015)

Bottom Line: My effort to use synchronously dividing cultures to examine the Escherichia coli cell cycle involved a 10-year struggle with failure after failure punctuated by a few gratifying successes, especially at the end.In this essay, I recount my personal journey in this obsessive experimental pursuit.That narrative is followed by a description of a simplified version of the "baby machine," a technique that was developed to obtain minimally disturbed, synchronously growing E. coli cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Florida Institute of Technology Melbourne, FL, USA.

ABSTRACT
My effort to use synchronously dividing cultures to examine the Escherichia coli cell cycle involved a 10-year struggle with failure after failure punctuated by a few gratifying successes, especially at the end. In this essay, I recount my personal journey in this obsessive experimental pursuit. That narrative is followed by a description of a simplified version of the "baby machine," a technique that was developed to obtain minimally disturbed, synchronously growing E. coli cells. Subsequent studies with this methodology led to an understanding of the basic properties of the relationship between chromosome replication and cell division. Accordingly, I end this reminiscence with a simple, fool-proof graphical strategy for deducing the pattern of chromosome replication during the division cycle of cells growing at any rate.

No MeSH data available.


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Argonne National Laboratory, 1968. Ole Maaløe facilitating discussion after a presentation by Charles Helmstetter at a Division of Biological and Medical Sciences symposium.
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Figure 2: Argonne National Laboratory, 1968. Ole Maaløe facilitating discussion after a presentation by Charles Helmstetter at a Division of Biological and Medical Sciences symposium.

Mentions: After a few ups and downs, humorously described in Cooper (1997), the relationship between chromosome replication and cell division became obvious. Two papers were then written and published in 1968 (Cooper and Helmstetter, 1968; Helmstetter and Cooper, 1968). The first contained new data on 3H-thymidine incorporation during the cycle of rapidly growing cells, and the second described a “model” to explain the general relationship between replication and division. The writing was a joint effort although I took primary responsibility for the first and Steve for the second. That division of labor proved wise due to Steve's skill at inventive prose. The first paper reflects my traditional, generally accepted writing style, segmented into: Introduction, Methods, Results, and Discussion. Steve simply wrote in a manner he felt was most informative, irrespective of expected norms. I have to believe his compositional skills are one reason the basic ideas in the second paper came across so easily to readers and are so frequently cited. Another reason lies in the presentation of the findings as a “model” when in fact it was primarily a description of our data and not a generalized model. The “model” states that the time for a round of chromosome replication (C) and the time between the end of a round of replication and cell division (D) are constants over a specific range of growth rates. Thus, cell division takes place C + D min after initiation of each round of chromosome replication. Subsequently, the model was extended to include (I), defined as the interinitiation time, i.e., the time required for the cell to achieve the potential to initiate chromosome replication (Helmstetter et al., 1968). Accordingly, in a purely phenomenological sense, E. coli duplication can be described as I + C + D, irrespective of the durations of I, C, and D. Later that same year, Ole Maaløe and I reconnected at Argonne National Laboratory during a presentation of the model (Figure 2).


A ten-year search for synchronous cells: obstacles, solutions, and practical applications.

Helmstetter CE - Front Microbiol (2015)

Argonne National Laboratory, 1968. Ole Maaløe facilitating discussion after a presentation by Charles Helmstetter at a Division of Biological and Medical Sciences symposium.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373376&req=5

Figure 2: Argonne National Laboratory, 1968. Ole Maaløe facilitating discussion after a presentation by Charles Helmstetter at a Division of Biological and Medical Sciences symposium.
Mentions: After a few ups and downs, humorously described in Cooper (1997), the relationship between chromosome replication and cell division became obvious. Two papers were then written and published in 1968 (Cooper and Helmstetter, 1968; Helmstetter and Cooper, 1968). The first contained new data on 3H-thymidine incorporation during the cycle of rapidly growing cells, and the second described a “model” to explain the general relationship between replication and division. The writing was a joint effort although I took primary responsibility for the first and Steve for the second. That division of labor proved wise due to Steve's skill at inventive prose. The first paper reflects my traditional, generally accepted writing style, segmented into: Introduction, Methods, Results, and Discussion. Steve simply wrote in a manner he felt was most informative, irrespective of expected norms. I have to believe his compositional skills are one reason the basic ideas in the second paper came across so easily to readers and are so frequently cited. Another reason lies in the presentation of the findings as a “model” when in fact it was primarily a description of our data and not a generalized model. The “model” states that the time for a round of chromosome replication (C) and the time between the end of a round of replication and cell division (D) are constants over a specific range of growth rates. Thus, cell division takes place C + D min after initiation of each round of chromosome replication. Subsequently, the model was extended to include (I), defined as the interinitiation time, i.e., the time required for the cell to achieve the potential to initiate chromosome replication (Helmstetter et al., 1968). Accordingly, in a purely phenomenological sense, E. coli duplication can be described as I + C + D, irrespective of the durations of I, C, and D. Later that same year, Ole Maaløe and I reconnected at Argonne National Laboratory during a presentation of the model (Figure 2).

Bottom Line: My effort to use synchronously dividing cultures to examine the Escherichia coli cell cycle involved a 10-year struggle with failure after failure punctuated by a few gratifying successes, especially at the end.In this essay, I recount my personal journey in this obsessive experimental pursuit.That narrative is followed by a description of a simplified version of the "baby machine," a technique that was developed to obtain minimally disturbed, synchronously growing E. coli cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Florida Institute of Technology Melbourne, FL, USA.

ABSTRACT
My effort to use synchronously dividing cultures to examine the Escherichia coli cell cycle involved a 10-year struggle with failure after failure punctuated by a few gratifying successes, especially at the end. In this essay, I recount my personal journey in this obsessive experimental pursuit. That narrative is followed by a description of a simplified version of the "baby machine," a technique that was developed to obtain minimally disturbed, synchronously growing E. coli cells. Subsequent studies with this methodology led to an understanding of the basic properties of the relationship between chromosome replication and cell division. Accordingly, I end this reminiscence with a simple, fool-proof graphical strategy for deducing the pattern of chromosome replication during the division cycle of cells growing at any rate.

No MeSH data available.


Related in: MedlinePlus