Lipid and fatty acid composition of freshwater cyanobacteria

Abstract

Four species of freshwater cyanobacteria (A&M cyZidricu, Anucystis n&Zans, Nostoc canilta and Nostoc muscorum) contained as major lipid classes monogalactosyldiacylglycerols, digalactosyldiacylglycerols, sulphoquinovosyldiacylglycerols and phosphatidylglycerols. Unlike photosynthetic eukaryotes, cyanobacteria incubated for 7 d in the dark suffered no decrease in the concentrations of these classes, except for N. museorum. Growth, photosynthesis and nitrogen fixation were 3040% lower after dark incubation. The nitrogen-fixing cyanobacteria, Anabaena cyliirdric, N. c d n u and N. museorurn, contained alcohol glycosides and a highly-polar unknown glycolipid at high concentrations. The proportion of these two lipid classes decreased in the dark in N. muscorum alone. Extracts from Anacystis nidulans and N. caninu, and to a lesser extent N. muscorum, contained sterols, whose concentration increased after dark incubation. Anubuenu cylindricu contained considerable concentrations of linolenic acid in its total lipid, which did not decrease on dark incubation, and was not present mainly in monogalactosyldiacylglycerols as in photosynthetic eukaryotes. Palmitoleic acid, which is primarily confined to phosphatidylglycerols in photosynthetic eukaryotes, was distributed among the major lipid classes of N. eanina.

Factors regulating epilithic biofilm carbon cycling and release with nutrient enrichment in headwater streams

“…Terminally branched fatty acids (i15:0 and a15:0) were attributed to heterotrophic bacteria as they are not commonly found in cyanobacteria (Parker et al, 1967;Merritt et al, 1991;Ahlgren et al, 1992). Due to its high concentration in many freshwater cyanobacteria (Sallal et al, 1990;Merritt et al, 1991;Ahlgren et al, 1992), PLFA 16:1x7 was used to track changes in the contribution of cyanobacteria. The relative abundance of these diagnostic PLFA can vary among microbial grouping given that relative phospholipid content varies among microbial groups (e.g., White, 1983;Cooksey et al, 1987;Findlay et al, 1989).…”

Enhanced accumulation of glycogen, lipids and polyhydroxybutyrate under optimal nutrients and light intensities in the cyanobacteriumSynechocystissp. PCC 6803

“…Cyanobacteria also synthesize lipids (LP) that are mainly composed of diacylglycerols (Sallal et al . ; Sheng et al . ) and can be transformed to biodiesel (Sheng et al .…”

Sulfoquinovose synthase – an important enzyme in the N‐glycosylation pathway of Sulfolobus acidocaldarius

“…Although there seems to be a tight correlation between SQDG and phototropic organisms, which implies that SQDG might play an important role for photosynthesis, the presence of SQDG does not always correlate with photosynthetic ability. Thus, some phototrophic bacteria lack or possess only small amounts of SQDG (Sallal et al ., 1990; Merritt et al ., 1991) while non‐photosynthetic organisms like Rhizobium meliloti and the extreme thermoacidophilic Alicyclobacillus acidocaldarius (Wisotzkey et al ., 1992) possesses SQDG (Langworthy et al ., 1976; Cedergreen and Hollingsworth, 1994). Deletion studies revealed that SQDG is important only under certain conditions such as phosphate limitation (Benning et al ., 1993); furthermore, it was recently demonstrated that the UDP‐sulfoquinovose synthase was upregulated under salt stress conditions, implying a important role for maintaining the integrity and stability of the thylakoid membrane under these stress conditions (Xu et al ., 2010).…”