Michiko Hori

Asymmetry of Mouth Morph of a Freshwater Goby, Rhinogobius Flumineus

Abstract Morphological analysis of a small freshwater goby, Rhinogobius flumineus, showed a distinct dimorphic asymmetry in the lower jaw. The mouth of each fish opened with a slight but definite distortion toward the right or left side, depending on the individual. Right-opening mouth (dextral) fish had a right lower jaw that was more protruded than the left one, and left-opening (sinistral) fish had a more protruded left lower jaw. No fish had laterally symmetric lower jaws, indicating that the asymmetry was different from ‘fluctuating asymmetry’. These fish used either the right or left side of the mouth when picking up food from the bottom, but neither dextral nor sinistral individuals used one side more frequently than the other side. The mouth asymmetry, however, was related to the stationary posture: dextral fish stayed on the bottom with the line of their bodies curved to the right more frequently than to the left, and vice versa for the sinistral fish. Genetics of the morph phenotype were investigated by observing the frequencies of morphs in F1 under captive breeding. Mouth dimorphism seems to be determined by the Mendelian one-locus-two-alleles system, in which dextrality is dominant over sinistrality and the dominant gene acts as the lethal one when in a homozygote.

Two novel synthetic methods for 1,4-anhydro-α-d-xylopyranose derivatives

Abstract Two novel methods for the syntheses of 1,4-anhydro-3- O -benzyl-2- O -pivaloyl- ( 1 ) and 2- O -acetyl-1,4-anhydro-3- O -benzyl- α - d -xylopyranose ( 2 ), starting materials for synthesizing stereoregular β -( 1 → 5)-xylofuranan by ring-opening polymerization are reported. Both synthetic routes start from d -xylopyranose, involve nine reaction steps, and give approximately 30–35% overall yields. The key reaction in the novel synthetic routes is the intramolecular nucleophilic attack of C-1 oxyanion on the C-5 position of 3- O -benzyl-5- O -( p -toluenesulfonyl)- α - d -xylofuranose ( 10 ), resulting in 1,5-acetal bond formation in high yield. The present synthetic routes enable us to prepare 1,4-anhydro- α - d -xylopyranose derivatives having different substituents at the 2- O - and the 3- O -positions.

Synthesis of d-xylopyranan by the ring-opening polymerization of 3-O-benzyl-α-d-xylopyranose 1,2,4-orthopivalate. Attempts to synthesize a stereoregular polymer

3-O-Benzyl-alpha-D-xylopyranose 1,2,4-orthopivalate (1) was newly synthesized and polymerized under cationic polymerization reaction conditions in order to synthesize stereoregular (1-->4)-beta-D-xylopyranan. Although the polymerization of orthopivalate 1 was carried out under various reaction conditions, a non-stereoregular polymer, but mainly consisting of (1-->4)-beta-xylopyranose units, was obtained. Comparing these results with those of glucose 1,2,4-orthopivalates, it was revealed that not only the substituents in the C-2 and C-3 positions, but also the CH(2)OR group in glucose 1,2,4-orthopivalate, largely contribute to (1-->4)-beta-glucosidic bond formation by the ring-opening polymerization.

Sulfated glycofuranans as inhibitors of melanoma lung metastasis

Chemically synthesized (1 → 5)-β-d-glucofuranan, (1 → 5)-β-d-galactofuranan, (1 → 5)-β-d-xylofuranan, (1 → 5)-α-L-arabinofuranan, natural xylan, and curdlan were sulfated to investigate their inhibitory activities on B16-BL6 lung metastasis and anticoagulant activities. (1 → 5)-β-d-Glucofuranan sulfate, (1 → 5)-β-d-galactofuranan sulfate, xylan sulfate, and curdlan sulfate had binding abilities with B16-BL6 melanoma lysate. The inhibitory activities of sulfated polysaccharides on B16-BL6 lung metastasis selected by heparin binding assay were in the order (1 → 5)-β-d-galactofuranan sulfate > (1 → 5)--β-d-glucofuranan sulfate > xylan sulfate ≫ curdlan sulfate. Furthermore, (1 → 5)-β-d-galactofuranan sulfate, (1 → 5)-β-d-glucofuranan sulfate, and xylan sulfate had not only high inhibitory activity on B16-BL6 lung metastasis but also low anticoagulant activity. The correlation between chemical structure and biological activity is discussed.

Communication: Synthesis of 3-O-Benzyl-β-L-Arabinofuranose 1,2,5-Orthopivalate as a Starting Monomer for Ring-Opening Polymerization

We have studied the ring-opening polymerizations of a variety of glucose orthoester derivatives and found that substituents on the monomer play an important role in stereo- and regioregularity of the resulting polymers.1-3 These substituent effects open the possibility of application to ring-opening polymerizations of other sugar orthoesters to give stereo- and regioregular polysaccharides. Additionally, the ring-opening polymerization of the galactose orthoester derivative4 gave stereoregular (1→5)-β-D-galactofuranan.