Vibrio tetraodonis subsp. pristinus subsp. nov., isolated from the coral Acropora cytherea at Palmyra Atoll,and creation and emended description of Vibrio tetraodonis subsp. tetraodonis subsp. nov

Strain OCN044^T was isolated from the homogenised tissue and mucus of an apparently healthy Acropora cytherea coral fragment collected from the western reef terrace of Palmyra Atoll in the Northern Line Islands and was taxonomically evaluated with a polyphasic approach. The morphological and chemotaxonomic properties are consistent with characteristics of the genus Vibrio: Gram-stain-negative rods, oxidase- and catalase-positive, and motile by means of a polar flagellum. Strain OCN044^T can be differentiated as a novel subspecies based on 21 differences among chemotaxonomic features (e.g., fatty acids percentages for C_12:0 and C_18:1 ω7c), enzymatic activities (e.g., DNase and cystine arylamidase), and carbon sources utilized (e.g., L-xylose and D-melezitose) from its nearest genetic relative. Phylogenetic analysis and genomic comparisons show close evolutionary relatedness to Vibrio tetraodonis A511^T but the overall genomic relatedness indices identify strain OCN044^T as a distinct subspecies. Based on a polyphasic characterisation, differences in genomic and taxonomic data, strain OCN044^T represents a novel subspecies of V. tetraodonis A511^T, for which the name Vibrio tetraodonis subsp. pristinus subsp. nov. is proposed. The type strain is OCN044^T (=?LMG 31895^T?=?DSM 111778^T).

     

Virtual ligand screening of α-glucosidase: Identification of a novel potent noncarbohydrate mimetic inhibitor

5-Thiazoleacetamide derivatives of AR122 and AR125 were screened as α-glucosidase inhibitors by in silico high-throughput screening from commercial drug-like small compound libraries. Inhibition of α-glucosidase with AR122 and AR125 is time dependent: with no preincubation, AR122 and AR125 are relatively moderate inhibitors, but interestingly, after a 120 min incubation, they were 50-fold more potent (AR122: IC(50)=2.47 μM and AR125: IC(50)=27.1 μM). Plots of ln [residual α-glucosidase activity %] versus preincubation time show a pseudo-first order kinetics for both inhibitors. Through dialysis of enzyme-inhibitor complexes, no activity recovery was shown. These results suggest that AR122 and AR125 constitute a new class of noncarbohydrate mimetic inhibitor with an irreversible mechanism.     

Tumor antigen occurs in N-glycan of royal jelly glycoproteins: honeybee cells synthesize T-antigen unit in N-glycan moiety

In our previous paper (Kimura, Y., et al., Biosci. Biotechnol. Biochem., 67, 1852-1856, 2003), we found that a complex type N-glycans containing beta1-3 galactose residue occurs on royal jelly glycoproteins. During structural analysis of minor components of royal jelly N-glycans, we found complex type N-glycans bearing both galactose and N-acetylgalactosamine residues. Detailed structural analysis of pyridylaminated oligosaccharide revealed that the newly found N-glycan had a complex type structure harboring a tumor marker (T-antigen) unit: Galbeta1-3GalNAcbeta1-4GlcNAcbeta1-2Manalpha1-6 (Galbeta1-3GalNAcbeta1-4GlcNAcbeta1-2Manalpha1-3) Manbeta1-4GlcNAcbeta1-4GlcNAc. To our knowledge, this may be the first report of the presence of the T-antigen unit in the N-glycan moiety of eucaryotic glycoproteins.     

Dosing-time dependent effect of dexamethasone on bone density in rats

AimsWhile glucocorticoids are widely used to treat patients with various diseases, they often cause adverse effects such as bone fractures. In this study, we investigated whether the decrease in bone density induced by glucocorticoid therapy was ameliorated by optimizing a dosing-time.Main methodsRats were administered with dexamethasone (Dex) orally (1 mg/kg/day) for 6 weeks at a resting or an active period. After the end of the treatment, bone density of femur, biomarkers of bone formation and resorption, and other biomedical variables were measured.Key findingsBone density of femur was significantly decreased by the 6-week treatment with Dex, and the degree of decrease in the 14 HALO (hours after light on) dosing group (an active period) was larger than that in the 2 HALO dosing group (a resting period). Although urinary calcium excretion was accelerated by Dex treatment, secondary hyperparathyroidism was not detected. Histomorphometry analysis showed that Dex suppressed bone resorption, which was larger in the 2 HALO than in the 14 HALO groups. These data indicate that Dex equally suppressed bone formation in the 2 and 14 HALO groups, but inhibited bone resorption more in the 2 HALO than in the 14 HALO groups.SignificanceThis study shows that the decrease in bone density induced by Dex was changed by its dosing-time.     

Genetic variation in the capsid region of human astrovirus serotype 4 isolated in Japan

The entire capsid regions of 12 serotype-4 astroviruses from Japan were sequenced and compared with those of other serotypes. Serotype-4 isolates were divided into two new subgroups. The intrasubgroup nucleic acid and deduced amino acid sequences were quite homologous (more than 93%), but slightly less so between subgroups (almost 85%). However, the serotype-4 sequences differed from those of serotypes 1, 2, 3, 5, 6, 7 and 8 (less than 50%). Determining whether these differences significantly alter the epidemiology and antigenicity will require further investigation.     

Closely Linked Polymorphic Markers for Determining the Autosomal Dominant Allele (Cy) in Rat Polycystic Kidney Disease

The Han:SPRD strain is an SD-background strainknown to be a model of polycystic kidney disease (PKD)expressed through an autosomal dominant gene (Cy).However, different genotypes of this strain cannot be identified in the neonatal period. First, toestablish an accurate method of determining thegenotypes (Cy/Cy, Cy/+, +/+) which cause differentdisease progressions, we used polymorphic markers on rat chromosome 5. PCR products of tissue DNAtemplated with D5Rat9 showed distinct patterns onelectrophoresis indicating three genotypes. Second, todetermine whether the same locus plays a major role inexpressing PKD, we performed linkage analyses in a [BN X(BN X Han:SPRD)F₁] backcross. Cy/Cy and Cy/+also caused PKD in a BN background. In this backcross,we discovered that D5Rat11 is located closer to the Cy locus than D5Mgh10, which is regardedas one of the closest loci. We conclude that D5Rat9 andD5Rat11 are useful markers for determining the presenceof the Cy allele, which is regarded as the gene responsible for PKD.     

Generation of polymorphic markers tightly linked to the thymus enlargement loci by phenotype-directed representational difference analysis

To obtain genetic markers linked to a specific genetic locus, genomic subtraction with a DNA pool of backcross or F₂ intercross animals with a specific genotype at the locus is known to be effective. To determine whether the pooling strategy is also effective for isolation of genetic markers linked to a quantitative phenotype that can potentially be controlled by multiple genetic loci, we tested the ability of representational difference analysis (RDA) to isolate genetic markers linked to the thymus enlargement observed in the BUF/Mna (BUF) rat. This is known to be controlled by single major and minor genes, Ten1 and Ten2, on Chromosomes (Chrs) 1 and 13, respectively, both of which have dose effects on the normal WKY/Ncj (WKY) allele. DNA from an inbred WKY rat was used as the tester, and the driver was prepared from a DNA pool of 12 (WKY × BUF)F₁× BUF backcross rats with high thymus ratios (thymus weight/body weight), expected to have dominance of the BUF allele in the responsible loci. By two RDA series with the restriction enzymes BglII and BamHI, respectively, 28 polymorphic markers were isolated, and 8 of them were shown to be linked to Ten1, and one to Ten2. One of the 8 markers linked to Ten1 demonstrated no recombination in 18 rats with high thymus ratios. RDA with a DNA pool based on a quantitative phenotype (phenotype-directed RDA) can thus be considered an efficient approach for direct isolation of polymorphic markers linked to a quantitative trait. Received: 15 April 1997 / Accepted: 8 May 1998