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Old Pole (old + pole)

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Life Sciences100%

Selected Abstracts

Tsr,GFP accumulates linearly with time at cell poles, and can be used to differentiate ,old' versus ,new' poles, in Escherichia coli

MOLECULAR MICROBIOLOGY, Issue 6 2008
Liyan Ping
Summary In Escherichia coli, the chemotaxis receptor protein Tsr localizes abundantly to cell poles. The current study, utilizing a Tsr,GFP fusion protein and time-lapse fluorescence microscopy of individual cell lineages, demonstrates that Tsr accumulates approximately linearly with time at the cell poles and that, in consequence, more Tsr is present at the old pole of each cell than at its newborn pole. The rate of pole-localized Tsr accumulation is large enough that old and new poles can always be reliably distinguished, even for cells whose old poles have had only one generation to accumulate signal. Correspondingly, Tsr,GFP can be reliably used to assign new and old poles to any cell without use of information regarding pole heritage, thus providing a useful tool to analyse cells whose prior history is not available. The absolute level of Tsr,GFP at the old pole of a cell also provides a rough estimate of pole (and thus cell) age. [source]

MukB colocalizes with the oriC region and is required for organization of the two Escherichia coli chromosome arms into separate cell halves

MOLECULAR MICROBIOLOGY, Issue 6 2007
Olessia Danilova
Summary The circular Escherichia coli chromosome is organized by bidirectional replication into two equal left and right arms (replichores). Each arm occupies a separate cell half, with the origin of replication (oriC) at mid-cell. E. coli MukBEF belongs to the ubiquitous family of SMC protein complexes that play key roles in chromosome organization and processing. In mukBEF mutants, viability is restricted to low temperature with production of anucleate cells, reflecting chromosome segregation defects. We show that in mukB mutant cells, the two chromosome arms do not separate into distinct cell halves, but extend from pole to pole with the oriC region located at the old pole. Mutations in topA, encoding topoisomerase I, do not suppress the aberrant positioning of chromosomal loci in mukB cells, despite suppressing the temperature-sensitivity and production of anucleate cells. Furthermore, we show that MukB and the oriC region generally colocalize throughout the cell cycle, even when oriC localization is aberrant. We propose that MukBEF initiates the normal bidirectional organization of the chromosome from the oriC region. [source]

Tsr,GFP accumulates linearly with time at cell poles, and can be used to differentiate ,old' versus ,new' poles, in Escherichia coli

MOLECULAR MICROBIOLOGY, Issue 6 2008
Liyan Ping
Summary In Escherichia coli, the chemotaxis receptor protein Tsr localizes abundantly to cell poles. The current study, utilizing a Tsr,GFP fusion protein and time-lapse fluorescence microscopy of individual cell lineages, demonstrates that Tsr accumulates approximately linearly with time at the cell poles and that, in consequence, more Tsr is present at the old pole of each cell than at its newborn pole. The rate of pole-localized Tsr accumulation is large enough that old and new poles can always be reliably distinguished, even for cells whose old poles have had only one generation to accumulate signal. Correspondingly, Tsr,GFP can be reliably used to assign new and old poles to any cell without use of information regarding pole heritage, thus providing a useful tool to analyse cells whose prior history is not available. The absolute level of Tsr,GFP at the old pole of a cell also provides a rough estimate of pole (and thus cell) age. [source]

Is Escherichia coli getting old?

BIOESSAYS, Issue 8 2005
Conrad L. Woldringh
Whether or not bacteria divide symmetrically, the inheritance of cell poles is always asymmetrical. Because each cell carries an old and a new pole, its daughters will not be the same. Tracking poles of cells and measuring their lengths and doubling times in micro-colonies, Stewart et al.1 observed that growth rate diminished in cells inheriting old poles and concluded that these cells are susceptible to aging. Here, their results are compared with studies on the variabilities of length and age at division. It is argued that the decreased growth rate in old pole cells falls within the expected variation and may therefore be sufficiently far from a catastrophe-like cell death through aging. BioEssays 27:770,774, 2005. © 2005 Wiley Periodicals, Inc. [source]