This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wood, T. H. Search for Related Content PubMed PubMed Citation Articles by Wood, T. H.

 Previous Article  |  Next Article 

J Bacteriol. 1968 December; 96(6): 2077-2084
Copyright © 1968 American Society for Microbiology. All Rights Reserved.

Effects of Temperature, Agitation, and Donor Strain on Chromosome Transfer in Escherichia coli K-12

¹ Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104

ABSTRACT

Recombinant production in Escherichia coli K-12 can be described by three parameters: (i) the distance x of a selected male marker from the donor origin; (ii) the gradient constant k (the probability of interruption of the donor chromosome per unit distance during transfer into a recipient cell); and (iii) the extrapolate number A (the probability that a donor cell will produce a recombinant inheriting the donor marker contiguous with the origin). It is usually assumed that chromosomal distances can be measured by marker entry times, i.e., that the velocity of chromosome transfer v is constant along the chromosome. The dependencies of k, A, x, and v on temperature, agitation during mating, and donor strain were studied. The transfer velocity of the HfrH chromosomal region from the origin to his increases 15-fold between 16 and 43 C, and the chromosomal regions studied have the same temperature dependence that was found for the separate transfer velocities of the O-trp and trp-his regions. These data and radiation studies on chromosome transfer indicate that, at a given temperature, chromosomal transfer velocity varies by less than 10% as the distance of any given region from the origin increases. The gradient constant k is temperature-independent between 20 and 45 C if mating times at different temperatures are inversely proportional to the chromosome velocities; also, k is insensitive to agitation during mating and is not decreased by mating on membrane filters. However, the extrapolate number A is highly temperature-dependent, having its maximum value between 30 and 38 C. These results suggest that the spontaneous interruption of transfer which produces the gradient of transfer is a property of the chromosome itself and not of the fragility of the connection between mating cells.