The chiral phase HPLC also confirmed that some bacteria contain significant amounts of the PG diastereomer (R,R isomer), the proportion of which gradually increased with increasing growth temperature, suggesting adaptation to environmental change . . Other ions found in the tandem MS spectrum are identical to the ions of nonderivatized 16:0/18:1-PG (standard); see also published paper by Ishioka et al. and Fig. including Table .