Abstract: | The sulpholipids of three species of freshwater and marine diatomNitzschia palae Kutz, Navicula muralis Lewin and Navicula incertaGrün, have been investigated under various culture conditions.The plant sulpholipid, sulphoquinovosyl diglyceride, was predominantlysynthesized in the light rather than in the dark while the unknownsulpholipids, designated as U1 and U2, were produced more inthe dark than in the light. It was found that cells starvedof carbon or sulphate utilized their sulpholipid reserve assources of these materials. Generally, cultures incubated inthe light and bubbled with air (with or without CO2) showeda high level of incorporation of 36S into sulpholipids. In culturesbubbled with oxygen-free nitrogen the incorporation of tracerwas very small. The photosynthetic and respiratory inhibitors,DCMU and DNP appreciably reduced the amount of tracer incorporatedinto the sulpholipids. |