Bimodal length frequency distribution in 0+aged masu salmon,Oncorhynchus masou,in a natural stream of southern Hokkaido

The frequency distribution of the fork length of 0⁺ aged masu salmon,Oncorhynchus masou, changed from unimodal to bimodal distribution in autumn of the years from 1982 to 1984 in the Mogusa River of southern Hokkaido, Japan. The bimodal distribution consists of two (upper and lower) modal groups. These two groups resulted from a difference in growth rate of 0⁺ aged individuals in autumn. Fish belonging to the upper modal group are assumed to be potential 1⁺ smolts. Whether 0⁺ aged parr transform into smolt or remain as parr in the following spring may be related to the growth rate of fish in the first autumn.     

Saponins can cause the agglutination of phospholipid vesicles

The interaction of saponins with phospholipid vesicles was investigated by means of liposomal agglutination or a precipitation assay. Ginsenoside-Rc, which has an α-l-arabinofuranose residue at the non-reducing terminus, exhibited remarkable agglutinability toward egg yolk phosphatidylcholine vesicles, while other saponins lacking this characteristic sugar residue showed less or no agglutinability. The molar ratio of ginsenoside-Rc to egg phosphatidylcholine in the aggregates was estimated to be 0.4–0.5 by a precipitation assay using ¹⁴C-labeled egg phosphatidylcholine vesicles. The agglutination was inhibited by p-nitrophenyl α-l-arabinofuranoside but not by p-nitrophenyl β-d-glucopyranoside or arabinogalactan. The results indicated that the α-l-arabinofuranose residue in ginsenoside-Rc should be important for the expression of the agglutinability. The agglutinability of ginsenoside-Rc toward lipid vesicles depended on both the polar head groups and fatty acyl chains of phospholipids. Egg yolk phosphatidylcholine vesicles were strongly agglutinated by ginsenoside-Rc, although sphingomyelin, phosphatidylethanolamine, phosphatidic acid and phosphatidylserine were less agglutinated. The agglutinability of ginsenoside-Rc was effective for phosphatidylcholines with short or unsaturated fatty acyl chains. The results suggested that the interaction of ginsenoside-Rc with phospholipid membranes should be affected not only by the chemical structure of the phospholipid but also by the membrane fluidity.     

UDP-GalNAc : GalNAc-mucin α-N-acetylgalactosamine transferase activity in human intestinal cancerous tissues

GalNAc transferase activities of 6 human intestinal cancerous tissues were examined using bovine submaxillary gland mucin and its desialylated derivative, asialomucin, as acceptors. A Triton X-100 extract of these tissues was used as an enzyme source. All the tissues examined had GalNAc transferase that catalyzes the transfer of GalNAc from UDP-GalNAc to serine or threonine residues of the polypeptide chain. One of 6 specimens showed in addition UDP-GalNAc:GalNAc-mucin α-GalNAc transferase activity, synthesizing a disaccharide unit, GalNAcα→ GalNAc, when asialomucin was used as an acceptor. This carbohydrate structure was deduced on the basis of results of gel filtration, exoglycosidase digestion, and high-voltage paper electrophoresis.GalNAc transferaseHuman intestinal cancerous tissueBovine submaxillary gland mucin O-Glycosidically linked sugar chain     

Cloning of the Escherichia coli gene for the stringent starvation protein

Summary In order to clone the Escherichia coli gene for the stringent starvation protein (SSP), we determined its N-terminal sequence as well as the sequence of two peptide fragments obtained by cyanogen bromide cleavage of the protein. We then chemically synthesized four sets of oligodeoxyribonucleotide mixtures that represented possible codon combinations for parts of these amino acid sequences. The synthetic oligonucleotides were labelled with ³²P at their 5-termini and used as hybridization probes to detect DNA fragments containing the complementary sequences. Genomic Southern hybridization of E. coli chromosomal DNA gave up to ten DNA fragments hybridizing with each probe but only a few hybridized with two or more of the probes. The latter fragments were coloned in pBR322. By determining partial base sequences with a rapid method and examining proteins encoded by the DNA fragments, we were able to show that we had isolated a clone containing the complete SSP structural gene.Abbreviations SSP stringent starvation protein - PTH phenylthiohydantoin     

Flavonoid glycosides of the roots of Glycyrrhiza uralensis

The structure of a flavanone glycoside from the roots of Glycyrrhiza uralensis has been confirmed as 4′-O-[β-d-apio-d-furanosyl-(1 → 2)-β-d-glucopyranosyl]liquiritigenin. In addition, two known flavonoid glucosides, ononin (a minor component) and liquiritin (a major component), were isolated from the same extract.     

In vitro growth of adult amphibian (Xenopus laevis) hepatocytes and characterization of hepatocyte-proliferating activity in homologous serum

Adult frog (Xenopus laevis) hepatocytes were found to proliferate in a culture medium containing adult homologous serum. Insulin and dexamethasone were required for a net proliferation of hepatocytes. Dose-response analysis showed that a low concentration of serum (greater than or equal to 0.5%) was enough to induce DNA synthesis and mitosis, but a higher concentration (5%) caused certain necrotic changes. Under optimal conditions, there was a two- to threefold increase in nuclei per culture 10 days after serum treatment. Heterologous sera (fetal bovine, calf and chick) showed less proliferative activity. Based on our results, hepatocyte-proliferating activity in adult frog serum is considered to be heat-unstable and acidic protein(s). Thus, adult frog serum may contain hepatopoietin possibly different from well-known growth factors.     

Stability enhancement and circular dichroism spectral anomaly as an indication of non-covalent interactions in histidine- and tyrosine-containing ternary copper(II)—amino acid systems

Visible absorption and CD spectral and potentiometric studies on the His- and Tyr-containing ternary copper(II) complexes Cu(A)(L-B), where A refers to L-His, D-His, or L-Tyr and B to Lys, Tyr, Trp, Phe, Ala, Val, Arg, Glu, Asn, Gln, Ser, or Thr, were made to study ligand-ligand interactions in the complexes. While the CD spectral magnitudes in the d—d region are additive in the absence of side chain interactions and can be estimated from the magnitudes for the ternary systems involving DL-A or DL-B, deviation from the additivity was observed for Cu(L-His)(L-B) (B = LysH, Tyr, Trp, or Phe) and Cu(L-Tyr)(L-Trp). From the stability constants determined at 25 °C and I = 0.1 M (KNO₃), the equilibrium constants, K, for the following hypothetical equilibria were calculated to be large (0.14–0.60) for formation of Cu(L-/D-His)(L-B)(B = Tyr or Trp) and Cu(D-His)(L-Phe) with Cu(en)(L-Ala) as standard: $Cu(A)(L?Ala)+Cu(en)(L?b)\stackrel{K}{?}Cu(A)(L?B)+Cu(en)(L?Ala)$ The positive values indicate the stabilization due to the stacking between the imidazole ring of His and the aromatic side chain of L-B. Solvent dependence of the CD spectra for Cu(L-His)(L-LysH) and Cu(L-His) L-Trp) further supported the existence of the intramolecular electrostatic and hydrophobic interactions.     

Axial ligation of nitrogenous bases to five-coordinate chloro-meso-tetraphenylporphyrinatochromium(III)

The axial ligations of nitrogenous bases to the five-coordinate chloro-meso-tetraphenylporphyrinatochromium(III) [Cr(III)(TPP)(Cl)] were studied in a non-coordinating solvent, dichloromethane (CH₂Cl₂), by spectrophotometric methods. A correlation exists between log K for the axial ligation:

and pK_a for the N-donor ligand. This correlation suggests that ligand to metal σ bonding contributes to the complex formation, rather than does metal to ligand π back-donation.     

On the sexual reproduction ofDictyosiphon foeniculaceus (Phaeophyceae,Dictyosiphonales)

Dictyosiphon foeniculaceus from Sweden and Newfoundland was studied in laboratory culture. Zoids from unilocular sporangia developed into dioecious microscopic filamentous gametophytes which produced uniseriate plurilocular gametangia in low temperatures (0 to 8 °C). Zygotes and unfused isogametes gave rise to filamentous protonemata on which parenchymatous macroscopic sporophytes were formed. Isolates from Sweden and Newfoundland were interfertile. Although formed in culture, genetically unisexual sporophytes were not detected in nature. Female gametes ofD. foeniculaceus produced a sexual pheromone. It was identified as finavarrene, which is also known as the sperm attractant inAscophyllum nodosum.