Novel mutation at the initiation codon in the Norrie disease gene in two Japanese families

We have identified a new mutation of Norrie disease (ND) gene in two Japanese males from unrelated families; they showed typical ocular features of ND but no mental retardation or hearing impairment. A mutation was found in both patients at the initation codon of exon 2 of the ND gene (ATG to GTG), with otherwise normal nucleotide sequences. Their mothers had the normal and mutant types of the gene, which was expected for heterozygotes of the disease. The mutation of the initiation codon would cause the failure of ND gene expression or a defect in translation thereby truncating the amino terminus of ND protein. In view of the rarity and marked heterogeneity of mutations in the ND gene, the present apparently unrelated Japanese families who have lived in the same area for over two centuries presumably share the origin of the mutation.     

Metabolism of non-phenolic diarylpropane lignin substructure model compound by Coriolus versicolor

Abstract A lignin substructure model, 1-(4-ethoxy-3,5-dimethoxyphenyl)-2-(4-ethoxy-3-methoxyphenyl)-propane-1,3-diol(I), was actively metabolized by a white-rot fungus Coriolus versicolor in low nitrogen stationary cultures favouring the ligninolytic activity in the fungus. Cleavage of the dimer I between C_α and C_β of the propanoid side chain was the major degradative reaction by the fungus.     

Enhancement of penicillin acylase activity by cultivating immobilized Kluyvera citrophila

Summary Whole cells of Kluyvera citrophila were immobilized in polyacrylamide gel. The penicillin acylase activity of immobilized whole cells was 60%–70% of native cells. When the immobilized cells were continuously cultivated for 40 h in an aerated fermentor containing peptone medium and were treated with alkali in order to remove -lactamase activity, the immobilized cells produced ampicillin up to 4.4 times faster than noncultivated cells.Ampicillin production was investigated in a column system using these cultivated immobilized whole cells. The cultivated immobilized cells showed excellent performance in continuous ampicillin production.     

A multiplicity of erythrocyte glycolipids of the neolacto series revealed by immuno-thin-layer chromatography with monoclonal anti-I and anti-i antibodies

The thin-layer-chromatography immunostaining procedure was applied to human erythrocyte glycolipids using monoclonal anti-i and anti-I antibodies which are directed against epitopes on linear and branched carbohydrate chains of the neolacto (poly-N-acetyl-lactosamine) series. An examination of native and mild-acid-treated glycolipids from normal adult (I_{adul t} antigen type), neonatal (i_cord) , and I-antigen-deficient adult (i_adult) erythrocytes enabled certain structural inferences to be made as follows: (a) cells of both I and i phenotypes contain a multiplicity of glycolipids of the neolacto series whose backbones consist of 8 or more sugar residues; (b) the octasaccharide backbones are predominantly linear in cells of i phenotype and branched in those of I type; and (c) more complex glycolipids having decasaccharide and larger backbones with both linear and branched sequences occur in erythrocytes of both phenotypes, 0     

Production of itaconic acid by Aspergillus terreus immobilized in polyacrylamide gels

Summary Living Aspergillus terreus cells were entrapped in polyacrylamide gels and employed in both replacement batch and continuous column reactors to produce itaconic acid from glucose.With the replacement batch reactor, maximum itaconic acid productivity was observed under the following conditions: pH 2.50, temperature at 35°C, addition of NH₄H₂PO₄ and MgSO₄·7H₂O. Using the continuous reactor, the maximum itaconic acid yield was 60 mg/h/40 g of gel. The biocatalyst activity or half-life was about 10 days.     

Effects of an inhibitor of glucosylceramide synthase on glycosphingolipid synthesis and neurite outgrowth in murine neuroblastoma cell lines.

1-Phenyl-2-decanolyamino-3-morpholino-1-propanol (PDMP), an effective inhibitor of UDP-glucose:ceramide glucosyltransferase, caused inhibition of cell growth in murine neuroblastoma cell lines. Metabolic labeling of glycosphingolipids with [14C]galactose in NS-20Y, Neuro2a, and N1E-115 cells showed reduced incorporation of radioactivity into gangliosides and neutral glycosphingolipids when threo-PDMP was present in the medium. Treatment of NS-20Y cells with threo-PDMP resulted in a time-dependent decrease in mass levels of gangliosides and neutral glycosphingolipids. After 24 h in the presence of 50 microM threo-PDMP, neutral glycosphingolipid mass was reduced to 32%, where glucosylceramide was the most affected (90% decrease). The ganglioside mass was reduced to 57% of the original content. Neurite outgrowth from neuroblastoma cells in serum-free medium was significantly inhibited by threo-PDMP in a dose-dependent manner. Threo-PDMP also caused retraction of neurites which had been induced to extend in serum-free medium. Pretreatment of cells with GM1 partially restored the ability of NS-20Y cells for neurite outgrowth in the medium containing threo-PDMP. These results suggest a possible role for glycosphingolipids in neurite outgrowth of murine neuroblastoma cells.     

A coenzyme A-independent transacylase is linked to the formation of platelet-activating factor (PAF) by generating the lyso-PAF intermediate in the remodeling pathway

The remodeling pathway for the biosynthesis of platelet-activating factor (PAF) consists of the following reaction sequence: alkylacylglycerophosphocholine----lyso-PAF----PAF. Results presented in this article describe a novel transacylase activity that generates the lyso-PAF intermediate, which can then be acetylated to form PAF. Ethanolamine-containing lysoplasmalogens, 1-acyl-2-lyso-sn-glycero-3-phosphoethanolamine, alkyllysophosphoethanolamine, unlabeled lyso-PAF, 1-acyl-2-lyso-GPC, where GPC is sn-glycero-3-phosphocholine, and choline-containing lysoplasmalogens were all able to stimulate the formation of [3H]lyso-PAF from a [3H]alkylacyl-GPC precursor pool associated with HL-60 cell (granulocytic type) membranes. Other glycerolipids containing free hydroxyl groups (3-alkyl-2-lyso-sn-glycero-1-phosphocholine, lysophosphatidylserine, lysophosphatidylinositol, diacylglycerols, alkylglycerols, and monoacylglycerols), cholesterol, phosphatidylcholine, and phosphatidylethanolamine had no stimulatory effect on the release of [3H]lyso-PAF from the prelabeled membranes under identical incubation conditions. The observed transacylase reaction is directly coupled to PAF production, since the addition of a lysoethanolamine plasmalogen preparation to HL-60 membranes in the presence of [14C]acetyl-CoA stimulated PAF formation; under these conditions the lysoethanolamine plasmalogen was acylated. The transacylase responsible for the release of lyso-PAF from the membrane-associated alkylacyl-GPC was not affected by Ca2+, EGTA, or a known phospholipase A2 inhibitor, p-bromophenacyl bromide. The fact that the unnatural analog of lyso-PAF, lysophosphatidylserine, and lysophosphatidylinositol did not influence transacylase activity, whereas detergents such as deoxycholate and Triton X-100 inhibited the activity, demonstrated the observed stimulatory effects of the choline- and ethanolamine-containing lysophospholipids on the formation of [3H]lyso-PAF from [3H]alkylacyl-GPC were not due to any detergent property of these lysophospholipids. Thus, we conclude a CoA-independent transacylase (possessing phospholipase A2/acyltransferase activities) can be responsible for the formation of the lyso-PAF intermediate in the remodeling route of PAF biosynthesis.     

GCR3 encodes an acidic protein that is required for expression of glycolytic genes in Saccharomyces cerevisiae.

Screening of a mutagenized strain carrying a multicopy ENO1-'lacZ fusion plasmid revealed a new mutation affecting several glycolytic enzyme activities. The recessive single nuclear gene mutation, named gcr3, caused an extremely defective growth phenotype on fermentable carbon sources such as glucose, while growth on respiratory media was almost normal. The GCR3 gene was obtained by growth complementation from a genomic DNA library, and the complemented strains had normal enzyme levels. GCR3 gene was sequenced, and a 99,537-Da protein was predicted. The predicted GCR3 protein was fairly acidic (net charge, -34). The C-terminal region was highly charged, and an acidic stretch was found in it.     

Increase in potential activities of protein phosphatases PP1 and PP2A in lymphoid tissues of autoimmune MRL/MpJ-lpr/lpr mice.

The differential assay conditions for protein phosphatases PP1, PP2A, and PP2C were extensively studied by using crude extracts from mouse lymphoid tissues as enzyme sources. Under these conditions, the protein phosphatase activities were measured in MRL/MpJ-lpr/lpr mice (MRL/lpr mice), autoimmune-prone mice, and MRL/MpJ(-)+/+ mice (MRL/+/+ mice) and C3H/HeJ mice as the controls. In MRL/lpr mice, significant alterations in protein phosphatase activities from those in the control mice were demonstrated. In spleen and liver from MRL/lpr mice, potential activities of PP1 and PP2A were distinctly elevated over those of the control mice. These elevations appeared to be due to accumulation of the abnormal lymphocytes that emerged in MRL/lpr mice. Although the PP1 activity in MRL/lpr lymph nodes was lower than those of normal spleen and thymus, it was greatly increased by Co(2+)-trypsin treatment so that the PP1 activity of MRL/lpr lymph nodes was the highest among those of all the tissues examined. In contrast, PP2C activity showed no remarkable alteration in the autoimmune disease model mice as compared with that in the control mice. These results demonstrated a specific elevation in potency of protein dephosphorylation in the tissues of MRL/lpr mice, suggesting a new explanation for the defect in signal transduction in this disease.     

Alpha-elastin coacervate as a protein liquid membrane: effect of pH on transmembrane potential responses.

A protein liquid membrane composed of coacervated alpha-elastin, a chemical fragmentation product of the biological elastic fiber protein, functioned as an amphoteric liquid ion-exchange membrane. Ionic permselectivities of the alpha-elastin coacervate membrane to a series of metal chlorides were investigated for the concentration-cell systems by the ordinary electrochemical measurements. Effects of pH on the transmembrane potential responses for NaCl, CaCl2, and MgCl2 systems were examined. Only in the Ca(2+)-containing system did potential responses stay at constant levels against the pH changes, whereas in the other systems, increasing pH caused potential changes, indicating an improvement of cationic permselectivity across the alpha-elastin coacervate membrane. It was suggested that the characteristic Ca2+ transport mechanisms across the alpha-elastin coacervate membrane are related in some way to the polypeptide backbone interactions specific and selective to Ca2+ ions.