RT Journal Article SR Electronic(1) A1 Onoda, T. A1 Oshima, A.YR 1988 T1 Effects of Ca2+ and a Protonophore on Growth of an Escherichia coli L-Form JF Microbiology, VO 134 IS 11 SP 3071 OP 3077 DO https://doi.org/10.1099/00221287-134-11-3071 PB Microbiology Society, SN 1465-2080, AB The influence of Ca2+ ions on the growth of an l-form (NC7) derived from Escherichia coli K12 was investigated. In a medium containing NaCl as osmotic stabilizer 1 mm-Ca2+ was required for optimal growth of the l-form, while with KCl as osmotic stabilizer, in a medium containing 0·1 or 1·0 mm-Ca2+, optimium growth was observed at 32 and 37°C, respectively. When the l-form, growing exponentially at 32 C in medium containing KCl and 0·1 mm-Ca2+, was shifted to 37 C growth was strikingly suppressed. In contrast, the suppression of growth in the presence of 1·0 mm-Ca2+ at 32°C was relieved when the culture was shifted to 37°C. When the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP), at a final concentration of 10 m, was added to a medium containing NaCl and sucrose as osmotic stabilizers, together with 10 mm-glucose, the parent strain could grow exponentially. In contrast, growth of the l-form was completely stopped by 10 m-CCCP under the same conditions. In the presence of 20 m-CCCP, the l-form accumulated more than twice as much 45Ca as in the absence of the protonophore. Thus, it is suggested that growth of the l-form NC7 is coupled to the protonmotive force. Possible mechanisms for the coupling of calcium to growth of the l-form are discussed., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-134-11-3071