Cell cycle analysis
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| - | + | '''1.Determination of initiation age (a<sub>i</sub>) and C+D''':[[Image:Theoretical_age_distr.jpg|left|200px]] | |
From flow cytometry analysis of cells treated with rifampicin and cephalexin (run-out histogram) the proportions of cells that had not initiated replication at the time of drug action (4-origin-cells, streaked) and cells that had initiated (8-origin-cells) can be estimated.The initiation age (a<sub>i</sub>) can be found from the theoretical age distribution described by this formula, | From flow cytometry analysis of cells treated with rifampicin and cephalexin (run-out histogram) the proportions of cells that had not initiated replication at the time of drug action (4-origin-cells, streaked) and cells that had initiated (8-origin-cells) can be estimated.The initiation age (a<sub>i</sub>) can be found from the theoretical age distribution described by this formula, | ||
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[[Image:C+D_1.jpg|left|250px]] | [[Image:C+D_1.jpg|left|250px]] | ||
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| + | '''2. Determination of the C and D periods:''' | ||
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| + | The C period is found from the ''oriC/terC'' ratio obtained by Southern blot analysis and the generation time (τ): | ||
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| + | '''''oriC/terC''=2<sup>C/τ</sup>''' | ||
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| + | The D period is found from the C+D and C period: | ||
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| + | '''D = (C+D) - C''' | ||
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| + | Example (continues): | ||
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| + | C period calculated from the ''oriC/terC'' ratio: 49 min | ||
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| + | D period = (C+D) – C | ||
| + | D period = 76 min – 49 min = 27 min | ||
Revision as of 10:31, 15 August 2008
Cell cycle analysis of Escherichia coli cells
C period = the time for a round of chromosome replication
D period = the time between the end of a round of chromosome replication and cell division
From flow cytometry analysis of cells treated with rifampicin and cephalexin (run-out histogram) the proportions of cells that had not initiated replication at the time of drug action (4-origin-cells, streaked) and cells that had initiated (8-origin-cells) can be estimated.The initiation age (ai) can be found from the theoretical age distribution described by this formula,
F = 2 - 2((τ-ai)/τ)
where F is the fraction of cells that had not initiated and τ is the generation time, or from the estimated graph of the theoretical age distribution (streaked portion).
The C+D period is estimated from the initiation age (ai), the generation time (τ) and the number of generations spanned per cell cycle.
Example:
4-origin-cells: 23 %
Generation time (τ): 27 min
Initiation age (ai): 5 min
2. Determination of the C and D periods:
The C period is found from the oriC/terC ratio obtained by Southern blot analysis and the generation time (τ):
oriC/terC=2C/τ
The D period is found from the C+D and C period:
D = (C+D) - C
Example (continues):
C period calculated from the oriC/terC ratio: 49 min
D period = (C+D) – C D period = 76 min – 49 min = 27 min
