Variation in Phospholipid Ester-Linked Fatty Acids and Carotenoids of Desiccated Nostoc commune (Cyanobacteria) from Different Geographic Locations.

Profiles of phospholipid fatty acids and carotenoids in desiccated Nostoc commune (cyanobacteria) collected from China, Federal Republic of Germany, and Antarctica and in axenic cultures of the desiccation-tolerant strains N. commune UTEX 584 and Hydrocoleum strain GOEI were analyzed. The phospholipid fatty acid contents of the three samples of desiccated Nostoc species were all similar, and the dominant compounds were 16:1omega7c, 16:0, 18:2omega6, 18:3omega3, and 18:1omega7c. In comparison with the field materials, N. commune UTEX 584 had a much higher ratio of 18:2omega6 to 18:3omega3 (5.36) and a significantly lower ratio of 18:1omega7c to 18:1omega9c (1.86). Compound 18:3 was present in large amounts in the samples of desiccated Nostoc species which had been subject, in situ, to repeated cycles of drying and rewetting, but represented only a small fraction of the total fatty acids of the strains grown in liquid culture. This finding is in contrast to the data obtained from studies on the effects of drought and water stress on higher plants. Field materials of Nostoc species contained, in contrast to the axenic strains, significant amounts of apocarotenoids and a P384 pigment which, upon reduction with NaBH(4), yielded a mixture of a chlorophyll derivative and a compound with an absorption maximum of 451 nm. A clear distinction can be made between the carotenoid contents of the axenic cultures and the desiccated field materials. In the former, beta-carotene and echinenone predominate; in the latter, canthaxanthin and the beta-gamma series of carotenoids are found.