Mono- and digalactosyldiacylglycerol composition of glaucocystophytes (Glaucophyta): A modern interpretation using positive-ion electrospray ionization/mass spectrometry/mass spectrometry

Abstract

Glaucocystophytes are freshwater algae that possess an almost-intact cyanobacterium, referred to as a cyanelle, as their photosynthetic organelle. Because the cyanelle represents an intermediate state in plastid evolution, glaucocystophytes have been the subject of several studies to characterize the genetics and biochemistry of their cyanelles. However, only a small handful of older studies exist on the composition of their lipids, particularly two major plastid lipids, mono-and digalactosyldiacylglycerol (MGDG and DGDG, respectively), found in all photosynthetic life. Our study has used a modern mass spectrometry approach, namely positive-ion electrospray ionization/mass spectrometry/mass spectrometry, to provide a fresh interpretation of the MGDG and DGDG composition of the species, Cyanophora paradoxa Korshikov and Glaucocystis nostochinearum Itzigsohn, representing two glaucocystophyte genera. We have found that the major forms of MGDG and DGDG (with sn-1/sn-2 regiochemistry) are 20:5/16:0 MGDG, 20:5/20:5 MGDG, 20:5/16:0 DGDG, and 20:5/20:5 DGDG. A comparison of these four forms, along with other more minor forms of MGDG and DGDG, to two examples of cyanobacteria has revealed that glaucocystophytes do not share intact forms of MGDG and DGDG with extant cyanobacteria, but may have maintained certain C16 and C18 cyanobacterial fatty acids.

Mono- and digalactosyldiacylglycerol composition of dinoflagellates. VI. Biochemical and genomic comparison of galactolipid biosynthesis betweenChromera velia(Chromerida), a photosynthetic alveolate with red algal plastid ancestry, and the dinoflagellate,Lingulodinium polyedrum

“…Such genetic proof will be needed to determine whether red algae-derived genes are indeed responsible for synthesizing and incorporating 20:5 into MGDG and DGDG, and should elucidate whether any of the responsible enzymes are targeted to the plastid. It should be noted that 20:5/20:5 MGDG and DGDG have been observed in chlorarachniophytes and glaucocystophytes (Leblond & Roche, 2009;Leblond et al, 2010b). Although these algae are seemingly unrelated to C. velia in terms of plastid ancestry (because chlorarachniophytes have a green algal secondary endosymbiont and glaucocystophytes have a cyanobacterial primary endosymbiont: references are listed by Leblond & Roche, 2009;Leblond et al, 2010b), they may serve as useful systems for future comparison.…”

“…It should be noted that 20:5/20:5 MGDG and DGDG have been observed in chlorarachniophytes and glaucocystophytes (Leblond & Roche, 2009;Leblond et al, 2010b). Although these algae are seemingly unrelated to C. velia in terms of plastid ancestry (because chlorarachniophytes have a green algal secondary endosymbiont and glaucocystophytes have a cyanobacterial primary endosymbiont: references are listed by Leblond & Roche, 2009;Leblond et al, 2010b), they may serve as useful systems for future comparison. The 20:5/16:0 fatty acid combination observed in C. velia, however, could also fit our model illustrated in Fig.…”

Surface Ornamentation of <i>Cyanophora paradoxa</i> (Cyanophorales, Glaucophyta) Cells as Revealed by Ultra-High Resolution Field Emission Scanning Electron Microscopy

“…This alga has been examined extensively as a model organism of primitive phototrophs (e.g. Sato et al 2005, Watanabe et al 2009, Frassanito et al 2010, Leblond et al 2010, Facchinelli et al 2013. Ultrastructural features of C. paradoxa were examined using transmission and scanning electron microscopy (TEM and SEM, respectively) to demonstrate that the cell periphery lacks a cell wall but consists of plasma membrane and flattened vesicles containing a plate just underneath the membrane (Hall and Claus 1963, Mignot et al 1969, Trench et al 1978, Kies 1979, Kugrens et al 1999.…”

Microalgae, a Potential Natural Functional Food Source – a Review

“…It can also produce monounsaturated fatty acids and saturated fatty acids such as oleic acid and palmitic acid, respectively. Phaeodactylum tricornutum is the diatom with a potential for the production of EPA, palmitoleic acid, palmitic acid, hexadecatrienoic acid, and myristic acid [Hu et Leblond et al [2010] observed that four organisms from three genera contained fatty acids, glycolipids, and triacylglycerol, with a dominant fraction of 16:0 and 22:5 ω-3.…”

“…The most important Cyanobacteria used in biotechnology are Spirulina (Arhrospira) platensis, Nostoc Table 1). The eukaryotic microalgae include several divisions: Chlorophyta (green algae) is the largest group, and most are unicellular or fi lamentous freshwater forms; Euglenophyta, which are fl agellated unicells that emerged from a secondary endosymbiosis between algae and a protozoan-like host; Rhodophyta, or red algae, resulting from their phycoerythrin content; Cryptophyta, in which most species are photosynthetically active motile unicells; Dinophyta or Dinofl agellata, which represent a wide group, though some species are not used due to their production of harmful toxins; Prymnesiophyta, also called Haptophyta; Glaucophyta, freshwater algae that possess an almost intact cyanelle as their photosynthetic organelle; Chlorarachniophyta, amoeboid/fl agellated eukaryotes; and Heterokontophyta, composed of the brown algae Phaeophyta, the yellow-green algae Eustimatophyta (or Xanthophyta), the golden algae Chrysophyta, and the Bacillariophyta (or Diatoms) [Duong et al, 2012;Barsanti et al, 2008;Leblond et al, 2010;McFadden et al, 1997].…”