Experimental and Theoretical Cross Sections for Escherichia coli Mutants B, B/r, and B_s-1 after Heavy-Ion Irradiation

Authors

Robert Katz, University of Nebraska-LincolnFollow
Rashidah Zachariah, University of Nebraska-Lincoln

Date of this Version

June 1993

Comments

Published in Radiation Research 134:3 (June 1993), pp. 261–264 Published by the Radiation Research Society; copyright © 1993 by Academic Press, Inc. Used by permission.

Abstract

Data for the inactivation of three Escherichia coli mutants by energetic heavy ions are fitted by the track theory of a one-hit detector in an extended target mode. The respective E₀’s are 46, 36.5, and 12.6 Gy for E. coli B, B/r, and B_s-1, and a₀, the assumed target radius, is 0.5 μm for all three. The parameter E₀, the D₃₇ with γ rays, is measured directly, while a₀ is fitted to the data. It is significant that neither a point target model nor calculations with a₀= 0.2 and 1.0 μm fit the data. Our fitted target radius, a₀, approximates the size of the bacterium. These results raise questions as to why the E. coli mutants are one-hit detectors, and concerning the differences in the E₀’s in relation to a mechanistic interpretation of cell killing.