The samples were homogenized in chloroform:methanol (2:1, v/v). 14C-total lipids were extracted according to Folch et al. (1957), dissolved in 5 mL of toluene–PPO 0.5%, and radioactivity (dpm) was counted. The results were expressed as μmol of 14C-glycine converted into 14C-total lipids·mg− 1 of protein·h− 1 of incubatio