Document Type

Article

Publication Title

Molecular Biology and Evolution

Publication Date

3-1991

Volume

8

Issue

3

Disciplines

Biology | Life Sciences

Abstract

A population of Escherichia coli initiated with a single clone developed extensive morphological and physiological polymorphism after being maintained for 773 generations in glucose-limited continuous culture. To understand the mechanisms of adaptation to this environment, total protein patterns of four adaptive clones and of the parent strains were examined by two-dimensional gel electrophoresis. Approximately 20% of the proteins (approximately 160 in absolute numbers) showed significantly different levels of expression in pairwise comparisons of parent and adapted clones. The extent of these changes points to the importance of mutations with regulatory and/or highly pleiotropic effects in the adaptive process. The four evolved clones all expressed fewer proteins than did the parent strain, supporting the hypothesis of energy conservation during evolutionary change. Forty-two proteins that could be assigned to known cellular functions were identified. The changes in some of them indicated that the evolved clones developed different adaptive mechanisms to glucose-limited environment. Changes were observed in the expression levels of proteins associated with translation, membrane composition, shock response, and active transport. A fraction of the changes could not be either explained or predicted from a consideration of the nature of the environment in which the clones evolved.

Keywords

Escherichiu coli, two-dimensional electrophoresis, adaptive changes, identification of pleiotropy

DOI

https://doi.org/10.1093/oxfordjournals.molbev.a040650

Rights

© 1991 by The University of Chicago. All rights reserved.

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