Porter, David (1984) Protein synthesis during differentiation of 'rhodomicrobium vanniellii' swarmer cells. PhD thesis, University of Warwick.

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Abstract

The role of sequential protein synthesis in the differentiation of Rhodomicrobium vannielii swarmer cells is investigated. The cell division cycle of this organism is discussed and compared with those of other organisms both prokaryotic and eukaryotic. The advantages of using budding bacteria in general and R. vannielii in particular in the study of the control of the cell division cycle is discussed.
Evidence is presented that the obligatory maturation period of the swarmer cell before DNA synthesis begins may be correlated with the prokaryotic I period and the eukaryotic G1 phase. The length of the swarmer cell maturation period is controlled by the availability of light probably acting at the level of energy availability. A computer model based on the hypothesis that swarmer cell maturation is inhibited by low light intensity due to rising optical density as cell numbers increase accurately predicts the increase in the proportion of swarmer cells in late exponential phase.
During the differentiation of synchronised swarmer cells the pattern of protein synthesis shows many qualitative and quantitative changes indicating sequential and periodic synthesis. Some proteins are limited in their distribution to a particular cell type such as the stalked cell or swarmer cell. Protein synthesis continues in the inhibited swarmer cell and a few proteins are specific to this stage of the cell division cycle while many more are specifically synthesised during differentiation. The possible means by which sequential protein synthesis could be controlled are discussed.
An 11.5 K protein, the synthesis of which is specific to the inhibited swarmer cell, is degraded as the cell differentiates when light limitation is removed. This degradation correlates with an increase in ATP levels in the cell. The possible role of the 11.5 K protein is discussed although this is at present speculative. Antibody to this protein has been prepared making purification by affinity chromatography and gene cloning possible lines of future research.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QP Physiology
Library of Congress Subject Headings (LCSH):	Proteins -- Synthesis, Biochemistry, Photosynthetic bacteria, Molecular biology, Cytology, Genetics
Official Date:	October 1984
Dates:	Date Event October 1984 Submitted
Institution:	University of Warwick
Theses Department:	Department of Biological Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Dow, Crawford S.
Sponsors:	Science and Engineering Research Council (Great Britain)
Extent:	xv, 254 leaves : illustrations
Language:	eng

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