and even single nucleotide polymorphisms in one or more of these genes could result in differential lactic acid sensitivity. Lacking full genome sequences for all of the strains used, however, precludes us from investigating this hypothesis. Regardless, by pH 3, all strains displayed diminished growth kinetics and failed to carbonate Cauldron (Fig. 3 and data
not shown), so terminal acidic shock likely has a common genetic or physiological determinant in these strains.