title: Humoral opsonins of the tunicate, Pyura stolonifera.
abstract: This study characterizes humoral opsonins from the tunicate, Pyura stolonifera. The predominant opsonic components in P. stolonifera hemolymph were found to be calcium-dependent lectins with broad carbohydrate specificities. The opsonic lectins were purified by carbohydrate affinity chromatography which eluted a complex pattern of proteins ranging in molecular mass from 80 to >200kDa. Reducing and two dimensional SDS-PAGE indicated that the diversity of mature lectins evident under non-reducing conditions resulted from the differential oligomerization of two polypeptide sub-units (35 and 22kDa). In addition to lectin-mediated opsonic activity, hemolymph was also found to contain proteolytically activated opsonins. These data suggest that multiple, possibly interactive opsonic systems co-exist in P. stolonifera.
authors.affiliation: Department of Biological Sciences, Macquarie University, NSW, 2109, North Ryde, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Pearce
authors.forename: R A
authors.initials: RA
authors.lastname: Newton
authors.forename: S V
authors.initials: SV
authors.lastname: Nair
authors.forename: D A
authors.initials: DA
authors.lastname: Raftos
mesh_terms: D000818:Animals; D002241:Carbohydrates; D002846:Chromatography, Affinity; D004492:Edetic Acid; D005434:Flow Cytometry; D006023:Glycoproteins / Q000378:metabolism; D037102:Lectins / Q000302:isolation & purification / Q000378:metabolism*; D009895:Opsonin Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010586:Phagocytes; D011485:Protein Binding; D014561:Urochordata / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D006023:Glycoproteins; D037102:Lectins; D009895:Opsonin Proteins; D004492:Edetic Acid