Skip to content Skip to navigation
University of Warwick
  • Study
  • |
  • Research
  • |
  • Business
  • |
  • Alumni
  • |
  • News
  • |
  • About

University of Warwick
Publications service & WRAP

Highlight your research

  • WRAP
    • Home
    • Search WRAP
    • Browse by Warwick Author
    • Browse WRAP by Year
    • Browse WRAP by Subject
    • Browse WRAP by Department
    • Browse WRAP by Funder
    • Browse Theses by Department
  • Publications Service
    • Home
    • Search Publications Service
    • Browse by Warwick Author
    • Browse Publications service by Year
    • Browse Publications service by Subject
    • Browse Publications service by Department
    • Browse Publications service by Funder
  • Help & Advice
University of Warwick

The Library

  • Login
  • Admin

Plasmid segregational stability in 'Escherichia coli'

Tools
- Tools
+ Tools

Jones, Ian Martin (1984) Plasmid segregational stability in 'Escherichia coli'. PhD thesis, University of Warwick.

[img]
Preview
PDF
WRAP_Theses_Jones_1984.pdf - Submitted Version - Requires a PDF viewer.

Download (8Mb) | Preview
Official URL: http://webcat.warwick.ac.uk/record=b3254991~S15

Request Changes to record.

Abstract

The technique of continuous culture has been used to study the segregatlonal stability of plasmids in Escherichia coli in the absence of selective pressure.

Conditions were established that allowed the detection of plasmid-free cells no matter how low their Initial frequency.
Using these conditions the segregational stability of two related multicopy plasmids (pDSII09 and pBR322) was examined.

pDSII09 was found to be stably Inherited throughout 120 generations of nutrient limited growth despite the observation that the plasmid copy number fell 4 to 5 fold during the culture period. By contrast, pBR322 was lost from chemostat culture after a lag of between 30 and 40 generations, a period during which (by analogy with pDSII09) its copy number had fallen about 2 fold.

The functional basis of the differential segregation exhibited by these plasmids was ascribed to the presence (on pDSII09) or absence (on pBR322) of a functional par (partition) signal that ensured the efficient segregation of plasmid molecules into daughter cells at division. Based on this hypothesis, experiments were done to examine the possibility for correction of the defective partitioning of pBR322 by complementation in cis and in trans.

In only two cases (both in cis) was complementation achieved. The first using a previously characterised par function from plasmid pSCIOI and the second using a fragment of plasmid pDSII09 that was considered (by argument) to be the region involved in its observed segregational stability.

Supportive evidence for the existence of partition elements amongst multicopy plasmids is cited, as is confirmatory work since published by other workers. A possible mechanism of par action is discussed.

Chemostat culture has also been used to examine the possibility of plasmid transfer by transformation within the chemostat. This study examined the effects of both growth rate and nutrient limitation on the transformability of Escherichia coli grown in continuous culture. The results obtained are discussed in relation to previously published transformation work using batch grown cells and a possible mechanism of plasmid transformation is suggested.
.

Item Type: Thesis (PhD)
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QR Microbiology
Library of Congress Subject Headings (LCSH): Escherichia coli, Plasmids
Official Date: January 1984
Dates:
DateEvent
January 1984UNSPECIFIED
Institution: University of Warwick
Theses Department: Department of Biological Sciences
Thesis Type: PhD
Publication Status: Unpublished
Supervisor(s)/Advisor: Primrose, S. B.
Sponsors: Science Research Council (Great Britain)
Format of File: pdf
Extent: viii, 164 leaves : illustrations
Language: eng

Request changes or add full text files to a record

Repository staff actions (login required)

View Item View Item

Downloads

Downloads per month over past year

View more statistics

twitter

Email us: wrap@warwick.ac.uk
Contact Details
About Us