Change of substrate specificity by polyamines of ribonucleases which hydrolyze ribonucleic acid at linkages attached to pyrimidine nucleotides.

The activities of ribonucleases (RNase HS and RNase A), which hydrolyze ribonucleic acid at linkages attached to pyrimidine nucleotides were stimulated by polyamines, while the activities of ribonucleases (RNase T₁ and RNase M), which attack ribonucleic acid at linkages attached to purine nucleotides were not influenced by polyamines. In the presence of polyamines, the cleavage of C_5′-O-P linkages adjacent to cytosine nucleotide was stimulated, while the cleavage of C_5′-O-P linkages adjacent to uracil nucleotides was inhibited slightly. The effect of polyamines on the activities of ribonucleases occured through the binding of the polyamines to nucleic acid.     

Phosphorylation of mononucleotides and formation of cytidine 5''-diphosphate-choline and sugar nucleotides by respiration-deficient mutants of yeasts.

Respiration-deficient mutants (Rho-, petite) of Saccharomyces carlsbergensis were obtained by treatment with trypaflavin (euflavine). Dried cells of these mutants phosphorylated mononucleotides to their triphosphates and further formed not only cytidine 5'-diphosphate-choline, but also sugar nucleotides, such as uridine 5'-diphosphate-glucose, guanosine 5'-diphosphate-mannose, etc. The activities were the same or slightly greater than those of the wild strain. These results showed that energy (adenosine 5'-triphosphate) necessary for phosphorylation of mononucleotides was sufficiently supplied by the glycolysis system.     

Different binding sites for the neuropeptide Y Y1 antagonists 1229U91 and J-104870 on human Y1 receptors

The peptidic Y1 antagonist 1229U91 and the non-peptidic antagonist J-104870 have high binding affinities for the human Y1 receptor. These Y1 antagonists show anorexigenic effects on NPY-induced feeding in rats, although they have completely different structures and molecular sizes. To identify the binding sites of these ligands, we substituted amino acid residues of the human Y1 receptor with alanine and examined the abilities of the mutant receptors to bind the radio-labeled ligands. Alanine substitutions, F98A, D104A, T125A, D200A, D205A, L215A, Q219A, L279A, F282A, F286A, W288A and H298A, in the human Y1 receptor lost their affinity for the peptide agonist PYY, but not for 1229U91 and J-104870, while L303A and F173A lost affinity for 1229U91 and J-104870, respectively. N283A retained its affinity for 1229U91, but not for PYY and J-104870. Y47A and N299A retained their affinity for J-104870, but not for PYY and 1229U91. W163A and D287A showed no affinity for any of the three ligands. Taken together, these data indicate that the binding sites of 1229U91 are widely located in the shallow region of the transmembrane (TM) domain of the receptor, especially TM1, TM6 and TM7. In contrast, J-104870 recognized the pocket formed by TM4, TM5 and TM6, based on the molecular modeling of the Y1 receptor and J-104870 complex. In conclusion, 1229U91 and J-104870 have high affinities for Y1 receptors using basically different binding sites. D287 of the common binding site in the TM6 domain could be crucial for the binding of Y1 antagonists.     

Profile of a nonylphenol-degrading microflora and its potential for bioremedial applications

Nonylphenol (NP) is an important intermediate in the production of various commercial and industrial materials, but is also known as a ubiquitous pollutant in urban aquatic environments. We recently studied the NP-degrading activities of microflora in several aquatic environments, and found a notable degrading activity for wastewater from a sewage treatment plant in Tokyo. This result led us to isolate NP-degrading microbes and identify biodegradation products. Using conventional plate culture techniques and molecular biological methods, Pseudomonas and Sphingomonas species, which are known for their degradation activities of many aromatic compounds, have been isolated. But it has also been found that Sphingomonas sp. (S-strain) is necessary and sufficient for the degradation of NP. Although the role of Pseudomonas sp. (P-strain) remains unclear, P-strain seems to provide some co-nutrients for the growth of S-strain. The degradation products were analyzed by GC/MS and NMR. More than 95% of NP was degraded within 10 days and aromatic compounds other than NP were not found, suggesting that the phenolic part of NP was completely degraded. We also examined the potential of S-strain for bioremedial applications. S-strain cells immobilized on chitosan or alginate beads retain their NP-degrading activity in flask-scale experiments. Furthermore, the chitosan-bound cells in a lab-scale bioreactor have been found to be persistent for repeated use, suggesting that S-strain is applicable to the treatment of NP-contaminated wastewater.     

Replication Study in a Japanese Population to Evaluate the Association between 10 SNP Loci,Identified in European Genome-Wide Association Studies,and Type 2 Diabetes

AimWe performed a replication study in a Japanese population to evaluate the association between type 2 diabetes and 7 susceptibility loci originally identified by European genome-wide association study (GWAS) in 2012: ZMIZ1, KLHDC5, TLE1, ANKRD55, CILP2, MC4R, and BCAR1. We also examined the association of 3 additional loci: CCND2 and GIPR, identified in sex-differentiated analyses, and LAMA1, which was shown to be associated with non-obese European type 2 diabetes.MethodsWe genotyped 6,972 Japanese participants (4,280 type 2 diabetes patients and 2,692 controls) for each of the 10 single nucleotide polymorphisms (SNPs): rs12571751 in ZMIZ1, rs10842994 near KLHDC5, rs2796441 near TLE1, rs459193 near ANKRD55, rs10401969 in CILP2, rs12970134 near MC4R, rs7202877 near BCAR1, rs11063069 near CCND2, rs8108269 near GIPR, and rs8090011 in LAMA1 using a multiplex polymerase chain reaction invader assay. The association of each SNP locus with the disease was evaluated using a logistic regression analysis.ResultsAll SNPs examined in this study had the same direction of effect (odds ratio > 1.0, p = 9.77 × 10^-4, binomial test), as in the original reports. Among them, rs12571751 in ZMIZ1 was significantly associated with type 2 diabetes [p = 0.0041, odds ratio = 1.123, 95% confidence interval 1.037–1.215, adjusted for sex, age and body mass index (BMI)], but we did not observe significant association of the remaining 9 SNP loci with type 2 diabetes in the present Japanese population (p ≥ 0.005). A genetic risk score, constructed from the sum of risk alleles for the 7 SNP loci identified by un-stratified analyses in the European GWAS meta-analysis were associated with type 2 diabetes in the present Japanese population (p = 2.3 × 10^-4, adjusted for sex, age and BMI).ConclusionsZMIZ1 locus has a significant effect on conferring susceptibility to type 2 diabetes also in the Japanese population.     

Studies on Mold Dextranases

Nine strains capable of producing dextranase were isolated from soil. Among them, a strain belonging to the genus Aspergillus was chosen as the best producer of the enzyme. The mold produced greater amounts of dextranase than those found in some strains in the genus Penicillium, when grown aerobically at 28°C for 5 to 6 days in medium containing 1% dextran, 1% NaNO₃ or polypeptone, 0.2% yeast extracts, 0.4% K₂HPO₄ and small amounts of inorganic salts, pH 8.5. From the comparative taxonomic experiments, the mold used here was identified to be a strain belonging to Aspergillus carneus.     

Induction of Manganese Superoxide Dismutase by Cytokines and Lipopolysaccharide in Cultured Mouse Astrocytes

Abstract: To determine whether cytokines or lipopolysaccharide (LPS) are involved in the induction of superoxide dismutase (SOD) in the nervous system, we examined the effects of these substances on the levels of SOD in cultured mouse astrocytes. Treatment of astrocytes with 10² to 10⁴ U/ml tumor necrosis factor-α for 3 days increased the levels of Mn SOD in a dose- and time-dependent manner to as much as six times the level under nontreated conditions. Treatment with 1.0 µg/ml LPS for 3 days elicited a fourfold increase in levels of Mn SOD, and the effect of LPS was also dose dependent. Furthermore, Mn SOD in astrocytes was induced by a 3-day exposure to interleukin-1α at concentrations of 10² or 10³ U/ml. However, these stimuli had no effect on levels of copper-zinc SOD (Cu/Zn SOD) in astrocytes. By contrast, interferon-γ did not change the levels of either Mn or Cu/Zn SOD in the cells. The results indicate that the selective induction of Mn SOD by cytokines and LPS, which has been observed in nonnervous tissues, may also occur in nervous tissues. The induction of Mn SOD may represent a mechanism for protection of cells from oxidative stress.     

Photosymbiotic ascidians from Pari Island (Thousand Islands,Indonesia)

Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo–West Pacific coral reefs.