The Dugesia ryukyuensis Database as a Molecular Resource for Studying Switching of the Reproductive System

The planarian Dugesia ryukyuensis reproduces both asexually and sexually, and can switch from one mode of reproduction to the other. We recently developed a method for experimentally switching reproduction of the planarian from the asexual to the sexual mode. We constructed a cDNA library from sexualized D. ryukyuensis and sequenced and analyzed 8,988 expressed sequence tags (ESTs). The ESTs were analyzed and grouped into 3,077 non-redundant sequences, leaving 1,929 singletons that formed the basis of unigene sets. Fifty-six percent of the cDNAs analyzed shared similarity (E-value<1E -20) with sequences deposited in NCBI. Highly redundant sequences encoded granulin and actin, which are expressed in the whole body, and other redundant sequences encoded a Vasa-like protein, which is known to be a component of germ-line cells and is expressed in the ovary, and Y-protein, which is expressed in the testis. The sexualized planarian expressed sequence tag database (http://planaria.bio.keio.ac.jp/planaria/) is an open-access, online resource providing access to sequence, classification, clustering, and annotation data. This database should constitute a powerful tool for analyzing sexualization in planarians

Selective Intracellular Delivery of Ganglioside GM3-Binding Peptide through Caveolae/Raft-Mediated Endocytosis

Glycosphingolipids are major components of the membrane raft, and several kinds of viruses and bacterial toxins are known to bind to glycosphingolipids in the membrane raft. Since the viral genes and pathogenic proteins that are taken into cells are directly delivered to their target organelles, caveolae/raft-mediated endocytosis represents a promising pathway for specific delivery. In the present study, we demonstrated the ability of an artificial pentadecapeptide, which binds to ganglioside GM3, to deliver protein into cells by caveolae/raft-mediated endocytosis. The cellular uptake of a biotinylated GM3-binding peptide (GM3BP)–avidin complex into HeLa cells was observed, and the cellular uptake of this complex was inhibited by an incubation with sialic acid or endocytic inhibitors such as methyl-ß-cyclodextrin, and also by an incubation at 4 °C. These results indicate that the GM3BP-avidin complex bind to GM3 in membrane raft, and are taken into cell through caveolae/raft-mediated endocytosis. The GM3BP-avidin complex was transported into cells and localized around the nucleus more slowly than a human immunodeficiency virus type 1 TAT peptide. Furthermore, the uptake of a green fluorescent protein (GFP) linked with GM3BP into HeLa cells was similar to that of the GM3BP–avidin complex, and the localization of the GM3BP-GFP fusion protein was markedly different with that of the TAT-GFP fusion protein. The uptake and trafficking of GM3BP were distinguished from conventional cell-penetrating peptides. GM3BP has potential as a novel peptide for the selective delivery of therapeutic proteins and materials into cells in addition to being a cell-penetrating peptide

Lanthanide borohydrido complexes for MMA polymerization: syndio- vs iso- stereocontrol

This paper presents an extensive study of the polymerization of MMA with borohydrido lanthanide complexes for the first time. Catalytic systems are made from a lanthanide derivative bearing zero one, or two bulky ligands: substituted cyclopentadienyl (Cp*' = C5Me4nPr, Cp4i = C5HiPr4, CpPh3 = H2C5Ph3-1,2,4), and/or diketiminate ([(p-tol)NN] = [(p-CH3C6H4)N(CH3)C]2CH), in the presence of variable quantities of alkylating agent. With BuLi in apolar medium, highly isotactic polymer (up to 95.6%) is formed. In THF, syndiotactic-rich PMMA is obtained whatever the nature of the cocatalyst (BuLi or MgnBu2). The presence of an electron-withdrawing ligand such as CpPh3 allows high syndioregularity, up to 81.8% at 0 ◦C, together with the highest conversion. There is quite good concordance between calculated and experimental molecular data in THF. Divalent Cp*'2SmII(THF) and (CpPh3)2SmII(THF) are active as single-component initiators; the former affords PMMA 88% syndiotactic at 0 ◦C