CHARACTERIZATION OF CELL WALL POLYSACCHARIDES OF THE COENCOCYTIC GREEN SEAWEED BRYOPSIS PLUMOSA (BRYOPSIDACEAE, CHLOROPHYTA) FROM THE ARGENTINE COAST¹

Abstract

Bryopsis sp. from a restricted area of the rocky shore of Mar del Plata (Argentina) on the Atlantic coast was identified as Bryopsis plumosa (Hudson) C. Agardh (Bryopsidales, Chlorophyta) based on morphological characters and rbcL and tufA DNA barcodes. To analyze the cell wall polysaccharides of this seaweed, the major room temperature (B1) and 90°C (X1) water extracts were studied. By linkage analysis and NMR spectroscopy, the structure of a sulfated galactan was determined, and putative sulfated rhamnan structures and furanosidic nonsulfated arabinan structures were also found. By anion exchange chromatography of X1, a fraction (F4), comprising a sulfated galactan as major structure was isolated. Structural analysis showed a linear backbone constituted of 3-linked β-d-galactose units, partially sulfated on C-6 and partially substituted with pyruvic acid forming an acetal linked to O-4 and O-6. This galactan has common structural features with those of green seaweeds of the genus Codium (Bryopsidales, Chlorophyta), but some important differences were also found. This is the first report about the structure of the water-soluble polysaccharides biosynthesized by seaweeds of the genus Bryopsis. These sulfated galactans and rhamnans were in situ localized mostly in two layers, one close to the plasma membrane and the other close to the apoplast, leaving a middle amorphous, unstained cell wall zone. In addition, fibrillar polysaccharides, comprising (1→3)-β-d-xylans and cellulose, were obtained by treatment of the residue from the water extractions with an LiCl/DMSO solution at high temperature. These polymers were also localized in a bilayer arrangement.

Tubular microfossils from ∼2.8 to 2.7Ga-old lacustrine deposits of South Africa: A sign for early origin of eukaryotes?

“…The bacteria reside either on the surface or within the algal cells (Hollants et al, 2011). Most algae, including siphonous varieties, excrete extracellular polymeric substances on their cell surface (Percival and McDowell, 1981;Ciancia et al, 2012). These excreta are densely settled and utilized by a great variety of heterotrophic bacteria (Lachnit et al, 2000;Goecke et al, 2010;Hollants et al, 2010Hollants et al, , 2012.…”

Diversity of Sulfated Polysaccharides From Cell Walls of Coenocytic Green Algae and Their Structural Relationships in View of Green Algal Evolution

“…Conversely, algae comprise of many distantly related groups of organisms, for some of which cell wall structures are better understood than others ( Popper et al, 2011 ; Domozych et al, 2012 ). Particularly, cell wall architecture from green macroalgae of the Ulvophyceae has been investigated in only a few cases ( Lahaye and Robic, 2007 ; Estevez et al, 2009 ; Fernández et al, 2010 ; Ciancia et al, 2012 ; Fernández et al, 2014 ; Fernández et al, 2015 ).…”

“… Possible structure for a fragment containing all the major structural features of sulfated polysaccharides (A) A galactan from Codium species, (B) An homogeneous fraction from Bryopsis plumosa , (C) Galactans from species in the Halimedaceae, (D) Pyranosic arabinan from Codium species, (E) Mannan from Codium species. Structures were proposed by the authors of this review based on the major components detected by Bilan et al, 2007 ; Estevez et al, 2009 ; Ciancia et al, 2012 ; Fernández et al, 2012 ; Fernández et al, 2013 ; Arata et al, 2015 ; Fernández et al, 2015 . …”

“…As far as we know, the only other genus in this suborder for which sulfated polysaccharides have been studied in detail is Bryopsis ( Ciancia et al, 2012 ). From a room temperature water extract, a linear 3-linked b- d -galactan, partially sulfated, mainly on C-6 and partially pyruvylated was isolated from B. plumosa .…”

Multicellularity in green algae: upsizing in a walled complex

“…For example in Codium , sulfated glucuronoxylomannans, glucuronoxylorhamnogalactans and) sulfated xyloarabinogalactans are major cell wall components ( Estevez et al, 2009 ; Fernandez et al, 2010 ). In the related Bryopsis , sulfated galactans and rhamnans are also major wall constituents ( Ciancia et al, 2012 ). In Ulva , a main constituent of the cell wall is ulvan whose backbone structure includes sulfated rhamnose residues linked to uronic acids, resulting in a repeated disaccharide unit β- D -glucuronosyl-(1,4)-α- L -rhamnose 3-sulfate, called aldobiouronic acid ( Lahaye and Robic, 2010 ).…”