CELL-WALL OF Lobophora variegata (OCHROPHYTA): EXTRACTION AND BIOCHEMISTRY OF SULFATED POLYSACCHARIDES

Complex cell wall composition of Lobophora variegata (Ochrophyta) rich in sulfated polysaccharides (LvSPs) is few understood. In this study, LvSPs were sequentially extracted and compared on their yield and structural properties. Decumbent morphotype was digested with papain (3 or 24 h) and then LvSPs3h-1→4 or LvSPs24h-1→6 quantified and examined their charge/mass by electrophoreses (agarose/polyacrylamide gels) vs. standard glycosaminoglycans stained with toluidine blue or Stains-All. The structural features were then analyzed by infrared spectroscopy. The results showed that the time impacted on the number and total extraction yield (15.63 ± 3.41 and 30.69 ± 0.42%, w w-1, for LvTSPs3h-1→4 and LvTSPs24h-1→6, respectively, p < 0.05). Chemical analyses reflected marked differences (LvTSPs3h-1→4 vs. LvTSPs24h-1→6) in charge showing a system of heterofucan and alginic acid (<100kDa), but without presenting degradation of the polymers coextracted from the algal cell wall. Therefore, complex wall of L. variegata is rich in acid polysaccharides with 24 h optimal extraction, suggesting a taxonomic adaptation to herbivory, when exposure to enviromental pressure.