Biomedical subjects

N Yamano

Publications and source records attributed to N Yamano.

7 recordsLinked to original sources

PubMed2005

Integrated nuclear data utilisation system for innovative reactors.

A five-year research and development project on an integrated nuclear data utilisation system was initiated in 2002, for developing innovative nuclear energy systems such as accelerator-driven systems. The integrated nuclear data utilisation system will be constructed as a modular code system, which consists of two sub-systems: the nuclear data search and plotting sub-system, and the nuclear data processing and utilisation sub-system. The system will be operated with a graphical user interface in order to enable easy utilisation through the Internet by both nuclear design engineers and nuclear data evaluators. This paper presents an overview of the integrated nuclear data utilisation system, describes the development of a prototype system to examine the operability of the user interface and discusses specifications of the two sub-systems.

Computer Graphics↗

PubMed2000

Purification and Characterization of N-Acetylglucosamine-6-phosphate Deacetylase from a Psychrotrophic Marine Bacterium, Alteromonas Species.

A psychrotrophic bacterium, strain Mct-9, which produced an N-acetylglucosamine-6-phosphate deacetylase, was isolated from a deep-seawater sample in the Mariana Trough. The Mct-9 strain was identified as Alteromonas sp. The native enzyme had a molecular mass of 164,000 Da, and was predicted to be composed of four identical subunits with molecular masses of 41,000 Da. The purified enzyme hydrolyzed N-acetylglucosamine (GlcNAc), GlcNAc-6-phosphate, and GlcNAc-6-sulfate. Considering the low K(m) and high k(cat)/K(m) for GlcNAc-6-phosphate, it probably acts as a GlcNAc-6-phosphate deacetylase in vivo. The enzyme was functional in the temperature range of 5 degrees to 70 degrees C and displayed optimal activity at 55 degrees C. The optimal temperature was higher than that of the deacetylase from the mesophilic bacterium Vibrio cholerae non-O1. The characteristics of the GlcNAc-6-phosphate deacetylase from Alteromonas sp. are unique among psychrotrophs and psychrophiles, whose intracellular enzymes are mostly thermolabile.

Journal Article↗

PubMed1997

Cloning and sequencing of the genes for N-acetylglucosamine use that construct divergent operons (nagE-nagAC) from Vibrio cholerae non-O1.

A 7.2-kb genomic DNA fragment containing N-acetylglucosamine-6-phosphate deacetylase gene (nagA) was cloned from the chitinase-producing bacterium Vibrio cholerae non-O1 strain 1148A (IFO 15429). Sequence analysis of the DNA fragment found three other complete open reading frames (ORFs) and the 5' end of an ORF. Amino acid sequences of two ORFs, ORF2 and ORF4, showed similarity with that of NagC, the repressor of nag operons and that of NagE, N-acetylglucosamine-specific transporter II(Nag) of phosphoenolpyruvate transport system of Escherichia coli, respectively. In the presence of N-acetylglucosamine, nagA and ORF2 (nagC) were co-transcribed. ORF4 (nagE), which is upstream from nagAC but is expressed in the opposite direction was also transcriptionally induced in the presence of N-acetylglucosamine. These results indicated that nagE-nagAC existed as divergent operons in V. cholerae non-O1. Unlike E. coli, nagB and nagD were not in the operons.

Acetylglucosamine↗

PubMed1996

Purification and characterization of N-acetylglucosamine 6-phosphate deacetylase with activity against N-acetylglucosamine from Vibrio cholerae non-O1.

An enzyme that deacetylates N-acetylglucosamine to glucosamine from Vibrio cholerae non-O1 was purified to homogeneity by sequential procedures. The native enzyme had a molecular mass of 190,000 Da and was predicted to be composed of four identical subunits with molecular masses of 45,000 Da. The purified enzyme hydrolyzed N-acetylglucosamine, N-acetylglucosamine 6-phosphate, and N-acetylglucosamine 6-sulfate, but not chitin oligosaccharides, and N-acetylgalactosamine. The deacetylase activity was completely abolished by N-ethylmaleimide, p-chloromercuribenzoate, EDTA, and Cu2+. On the other hand, the activity was activated by Co2+. The amino-terminal amino acids of the purified enzyme were sequenced. Among the 22 N-terminal amino acid residues, 12 residues of Vibrio deacetylase were identical with that of Escherichia coli GlcNAc 6-phosphate deacetylase.

Acetylglucosamine↗

PubMed1992

In vivo biotinylation of fusion proteins expressed in Escherichia coli with a sequence of Propionibacterium freudenreichii transcarboxylase 1.3S biotin subunit.

Biotinylation of fusion proteins in E. coli was studied using a sequence of Propionibacterium freudenreichii transcarboxylase 1.3S biotin subunit. As the biotinylation sequence, we examined two sequences: one was of amino acid residues [84-123] of 1.3S, a partial sequence containing a region from a conserved tetrapeptide (Ala-Met-Bct-Met) around the biotinyl lysine (Bct) to the carboxyl terminal; the other was of an almost entire sequence [18-123]. We constructed recombinant plasmids for fusion proteins of beta-galactosidase, of chloramphenicol acetyltransferase, and of alkaline phosphatase. We found the biotinylation in the [18-123] sequence fused to alkaline phosphatase.

Amino Acid Sequence↗

PubMed1990

Essential role of nitric oxide in descending inhibition in the rat proximal colon.

Possible mediators of descending inhibition in the rat proximal colon were studied. Localized distension with a small balloon caused relaxation of the circular muscle on the anal side of the distended region. This relaxation was still observed after the colonic segment had been desensitized to ATP, neurotensin and vasoactive intestinal peptide, so these compounds seem unlikely to mediate descending inhibition. Nitro-arginine inhibited the relaxation induced by the distension, and L-arginine counteracted the effect of nitro-arginine. Nitric oxide, isoamylnitrate and sodium nitroprusside caused relaxation. These results strongly suggest an essential role of nitric oxide in descending relaxation in the rat proximal colon.

Adenosine Triphosphate↗

PubMed1990

Differences in control of descending inhibition in the proximal and distal regions of rat colon.

1. Descending inhibition in the proximal and distal portions of rat colon was studied separately, in vitro. 2. In the proximal colon, localized distension with a small balloon caused three types of response (contraction; relaxation; relaxation, then contraction) of the circular muscle on the anal side of the distended region. 3. Distension caused descending relaxation of circular muscle in all segments of the proximal colon, although for this prostaglandin F2 alpha (PGF 2 alpha) was necessary in some segments to increase muscle tone. 4. Atropine and guanethidine did not inhibit this descending relaxation, but tetrodotoxin did. 5. Hexamethonium inhibited the descending relaxation in 14 of 17 preparations of proximal colon tested, but not in the others. 6. In the distal colon, distension consistently caused an increase in the tone of the circular muscles. Descending relaxation was observed only after development of higher tone. Atropine and guanethidine did not inhibit the relaxation, but tetrodotoxin did. 7. Hexamethonium did not inhibit the descending relaxation in most of the preparations of distal colon examined. 8. AF64A, an inhibitor of choline uptake, inhibited the response mediated by cholinergic neurons in vitro to electrical transmural stimulation of the longitudinal muscle of proximal colon. 9. Treatment of colonic preparations with AF64A in vitro resulted in inhibition of descending relaxation in those of proximal, but not those of distal, colon. 10. The participation of intrinsic cholinergic neurones in the descending neuronal pathway is strongly suggested by the results in the proximal colon, but less so in the distal colon. 11. The tone and spontaneous contractile activity of colonic circular muscles are discussed in relation to their neuronal control.

Animals↗