title: Extracellular polysaccharide production by thraustochytrid protists.
abstract: Four strains of marine stramenopilan protists, the thraustochytrids, were studied for their ability to produce extracellular polysaccharides (EPSs). Observations by light and scanning electron microscopy revealed the production of a matrix of EPS around groups of cells in stationary cultures. EPS in shake culture filtrates ranged from 0.3 to 1.1 g/L. EPS production, which was studied in greater detail in 2 isolates, SC-1 and CW1, increased with age of cultures, reaching a peak in the stationary phase. Anion exchange chromatography yielded a single fraction of the EPS of both species. The EPS contained 39% to 53% sugars, besides proteins, lipids, uronic acids, and sulfates. Molecular weight of the EPS produced by SC-1 was approximately 94 kDa, and that of CW1, 320 kDa. Glucose formed the major component in the EPS of both isolates-galactose, mannose, and arabinose being the other components. Cultures of both isolates survived air-drying up to a period of 96 hours, suggesting a role for EPS in preventing desiccation of cells.
authors.affiliation: National Institute of Oceanography, Dona Paula, Goa, 403 004, India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Jain
authors.forename: Seshagiri
authors.initials: S
authors.lastname: Raghukumar
authors.forename: R
authors.initials: R
authors.lastname: Tharanathan
authors.forename: N B
authors.initials: NB
authors.lastname: Bhosle
mesh_terms: D000818:Animals; D002244:Carbon / Q000378:metabolism; D002852:Chromatography, Ion Exchange; D056890:Eukaryota / Q000378:metabolism* / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011134:Polysaccharides / Q000096:biosynthesis / Q000302:isolation & purification*; D013045:Species Specificity
chemical_list: D016326:Extracellular Matrix Proteins; D011134:Polysaccharides; D002244:Carbon