title: Isolation and characterization of low density detergent-insoluble membrane (LD-DIM) fraction from sea urchin sperm.
abstract: The low density detergent-insoluble membrane (LD-DIM) fraction was obtained by a sucrose-density gradient centrifugation from sperm of three sea urchin species, Hemicentrotus pulcherrimus, Strongylocentrotus purpuratus, and Anthocidaris crassispina. These LD-DIM preparations were characterized by enriched glycosphingolipids (GSL) including gangliosides and sulfatide (SLF), having more than 50% of the total amount of GSL present in these sperm. Interestingly, a minor component of H. pulcherrimus sperm (HO3S-->8Neu5Acalpha2-->8Neu5Acalpha2-->6Glcbeta1++ +-->Cer) was shown to be even more enriched in the LD-DIM as revealed by using monoclonal antibody (mAb.3G9) speific to this ganglioside. In addition to the GSL, phosphatidyl-serine (PS) and diacylglcerol (DG) were enriched in the LD-DIM. On the other hand, cholesterol (CL) and sphingomyelin (SM) were not so enriched, which contrasted with the LD-DIM from Madin-Darby canine kidney (MDCK) cells, where CL and SM were reported to be abundant. Because mammalian somatic cell-derived DIMs have been proposed to be associated with functional signal transduction, it seems possible that the ganglioside-enriched LD-DIM in sea urchin sperm can participate in binding to eggs and the subsequent egg activation process. To our knowledge this is the chemical characterization of the LD-DIM fraction of a gametic cell.
authors.affiliation: Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohta
authors.forename: C
authors.initials: C
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Matsuda
authors.forename: M
authors.initials: M
authors.lastname: Toriyama
authors.forename: W J
authors.initials: WJ
authors.lastname: Lennarz
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D002460:Cell Line; D002855:Chromatography, Thin Layer; D003902:Detergents; D004285:Dogs; D005732:Gangliosides / Q000737:chemistry / Q000302:isolation & purification; D008297:Male; D008563:Membrane Lipids / Q000737:chemistry / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D012617:Sea Urchins; D012995:Solubility; D013094:Spermatozoa / Q000737:chemistry*
chemical_list: D003902:Detergents; D005732:Gangliosides; D008563:Membrane Lipids