title: False fertilization in sea urchin eggs induced by diabolin, a 120K kelp protein.
abstract: A 120K lectin-like protein was isolated from the kelp Laminaria diabolica (Oni-kombu), with a unique activity to induce false fertilization specifically in the eggs of the sea urchin Hemicentrotus pulcherrimus. The protein designated as "diabolin" rendered the unfertilized egg forms and elevated the fertilization envelope without insemination at 18 nM half-maximally. Those eggs with elevated fertilization envelopes, however, could not enter into normal cleavage or further development, and hence the proliferation of the sea urchin was hindered. Diabolin, thus, by its unique defense mechanism protects the kelp from the predator sea urchin. It was partially sequenced and found to have the highest homology with phytoene dehydrogenase from the plant virus Erwinia uredovora. A question was left to be solved as to how the kelp on the southeast coast of Hokkaido Island could develop the defense mechanism against the sea urchin on Honshu Island separated by Tsugaru Straits.
authors.affiliation: Department of Biochemistry, Tokyo Metropolitan Institute of Gerontology, Japan. nomura@tmig.or.jp
authors.forename: K
authors.initials: K
authors.lastname: Nomura
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D020418:Algal Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004885:Erwinia / Q000201:enzymology; D005306:Fertilization / Q000187:drug effects*; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010063:Ovum / Q000166:cytology / Q000187:drug effects*; D010088:Oxidoreductases / Q000737:chemistry; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D012617:Sea Urchins / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D012624:Seaweed / Q000737:chemistry*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
chemical_list: D020418:Algal Proteins; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C410953:diabolin protein, Laminaria diabolica; D010088:Oxidoreductases; C022398:phytoene dehydrogenase