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Y Tanji

Publications and source records attributed to Y Tanji.

At least 37 records · Page 2Linked to original sources
PubMed1999

Evidence for a novel Chlorella virus-encoded alginate lyase.

To clone the genes encoding lysis protein from a Chlorella virus, water samples were collected from 13 aquatic environments located in the Kanto area of Japan. Eight water samples contained plaque-forming viruses on Chlorella sp. NC64A, but no virus was detected in the other five samples. A novel Chlorella virus, CVN1, was isolated from the Inba-numa marsh sample. CVN1 genomic DNA was partially digested and shotgun cloned into pUC118 to identify the genomic region responsible for the lytic phenotype on Chlorella sp. NC64A. A DNA fragment which encoded two ORFs, ORF1 and ORF2, was obtained by antialgal assay. The ORF2 gene product, CL2, consisted of 333 amino acids showing antialgal activity not only on the original host of Chlorella sp. NC64A, but also on the heterogeneous hosts of Chlorella vulgaris C-27 and C. vulgaris C-207. CL2 showed a weak homology (19.8% amino acid identity) to mannuronate lyase SP2 from Turbo cornutus. CL2 in Escherichia coli cells was purified using a nickel chelate column. Lyase activity of purified CL2 on alginic acid was observed in an enzyme assay. The specific activity of purified CL2 was 2.1x10(-2) U mg(-1), the optimum pH for enzymatic activity was 10.5, and Ca(2+) was required for enzyme activity. This is the first report of a Chlorella virus protein with lyase activity.

Alginates↗
PubMed1999

Ovarian carcinoma with fistula formation to the sigmoid colon and ileum: report of a case.

We describe herein an extremely rare case of clear cell type ovarian carcinoma resulting in fistula formation into the colon and intestine. The patient was a 61-year-old woman in whom a large tumor with extravasation from the sigmoid colon was found by barium enema examination. The tumor was preoperatively diagnosed as left ovarian cancer by angiography which showed the tumor feeder arising from the left ovarian and uterine arteries.

Adenocarcinoma, Clear Cell↗
PubMed1999

Structural analysis of a biofilm which enhances carbon steel corrosion in nutritionally poor aquatic environments.

Carbon steel coupons were exposed to nutritionally-poor synthetic wastewater inoculated with activated sludge from a municipal waste water plant. Biofilm formation was observed after one day incubation, and the thickness of the film increased proportionally with the incubation period. Mass loss of the coupons was also proportional to the incubation time, and reached 70.4 (mg/cm2) after incubation for 140 d. The observed mass loss was 5 times as much as that under sterile conditions. To characterize the microbiologically influenced corrosion (MIC) of carbon steel, structural analysis of the biofilm was performed. Rapid decrease in the dissolved oxygen (DO) concentration in the zone near the surface of the biofilm was observed by a microelectrode mounted on a micromanipulator. Heterogeneous distribution of the DO concentration on the surface of the steel plate was observed after multiple analyses. The heterogeneous structure of the biofilm composed of viable cells, inanimate objects, voids and pores was elucidated by confocal scanning laser microscopy. Concentrations of both aerobic bacteria and sulphur-reducing bacteria in the biofilm decreased with the incubation time, indicating that the increase in the biofilm thickness reflected an increase in the density of dead microbial cells or in extracellular polymer accumulation by the microbes. The average roughness of the metal surface observed after 112 d of incubation was +/-7.14 microm, which was 14.1% of the average thickness of the coupons. These observations indicated that uneven distribution of the DO profile and the cell concentration were critical for MIC of the carbon steel.

Journal Article↗
PubMed1999

Enhanced microbial adaptation to p-nitrophenol using activated sludge retained in porous carrier particles and simultaneous removal of nitrite released from degradation of p-nitrophenol.

In order to examine the microbial degradation of p-nitrophenol (PNP) by a mixed culture system and simultaneous removal of nitrite released via the degradation, an activated sludge retained in porous carrier particles and a suspension culture as a control were acclimated to artificial sewage containing PNP as the sole carbon source. The adaptation of microbes retained in porous carrier particles to PNP was faster than that of suspended microbes by more than 20 d. After microbial adaptation to PNP, it was degraded completely without significant accumulation of intermediate metabolites. The PNP degradation activity of the retained microbes was more than 2 times higher than that of the suspended microbes. By increasing the retained microbial concentration, nitrite released from the degraded PNP was removed by denitrification. This research demonstrates that using microbes retained in porous carrier particles is not only effective for reduction of acclimation time but also enables simultaneous removal of the nitrogen compounds resulting from the degradation of nitroaromatics.

Journal Article↗
PubMed1999

Cloning and expression of a gene encoding the lytic functions of Bacillus amyloliquefaciens phage: Evidence of an auxiliary lysis system.

A bacteriophage specific to Bacillus amyloliquefaciens, a gram-positive bacterium, was isolated from a local sewage treatment center. Using a lysis assay, a gene, lys1521, was isolated and its nucleotide sequence revealed one open reading frame of 375 bp. Homology studies showed amino acid alignment similarity with gene 5A of Bacillus subtilis phages PZA and phi29. Overexpression of the cloned gene yielded a 13 kDa protein corresponding to the predicted gene product. Despite the fact that no significant homology with known cell wall lytic enzymes was apparent, the lytic profile obtained in an in vivo expression assay showed that lys1521 had cell wall hydrolysis activity. This is a significant revelation since the function of the homologous gene 5A product of phage phi29 has been suggested to be required for the in vivo elongation of phage DNA replication. The lys1521 gene could be evidence of the presence in gram-positive bacteriophages of a third lysis gene in addition to the well characterized two-step lysis system.

Journal Article↗
PubMed1998

Antitumor effect of medium-chain triglyceride and its influence on the self-defense system of the body.

Medium-chain triglyceride (MCT), long-chain triglyceride (LCT), and their mixture were compared in reference to both cytotoxic effect against human tumor cells and influence on the immune system. MCT showed more potent cytotoxicity than LCT. Continuous contact with MCT also inhibited the cytotoxic effect of lymphokine-activated killer (LAK) cells much more strongly than LCT. However, there is a discrepancy between the concentration of MCT, or the mixture, that could suppress the growth of tumor cells and the concentration that inhibited the cytotoxicity of LAK cells. Moreover, no damage was observed in PBL or LAK cells or in their cytotoxicity when the cells were incubated with TG for 2 h a day. Thus, short-term contact with TG could inhibit tumor growth while immune system was maintained within normal range. Clinically fine control of the concentration of injected triglycerides, especially MCT, can be expected to provide potent antitumor effect and maintenance of normal immune system.

Antineoplastic Agents↗
PubMed1997

Immunohistochemical Detection of P-glycoprotein in Breast Cancer and Its Significance as a Prognostic Factor.

Overexpression of P-glycoprotein (Pgp) in tumors is one of the major mechanisms which mediates the multidrug resistance (MDR) phenotype. To evaluate the prognostic significance of Pgp in breast cancer, Pgp expression was examined in paraffin-embedded tissue sections of 94 breast cancer specimens by immunohistochemistry. Tissue specimens were obtained by mastectomy without preoperative chemotherapy. UIC2 monoclonal antibody which recognizes an extracellular epitope of human Pgp was employed. Of the 94 breast cancer specimens, 35(37.2%)were positive for Pgp expression. Pgp expression had no correlation with menopausal or hormone receptor status, axillary Iymph node involvement or tumor size. However, a significant correlation was observed between Pgp expression and disease relapse (p=0.0322). Pgp-positive patients showed a significantly shorter disease-free survival period than Pgp-negative patients by the Kaplan-Meier method (p=0.0433). These results suggest that immunohistochemical detection of Pgp in breast cancer tissue may have prognostic value after radical operation.

Journal Article↗
PubMed1997

The N-terminal region of hepatitis C virus-encoded NS5A is important for NS4A-dependent phosphorylation.

We previously showed that two proteins, a 56-kDa protein (p56) and a 58-kDa protein (p58), are produced from the hepatitis C virus (HCV) nonstructural 5A region (NS5A) and that the production of p58 is enhanced by the presence of NS4A (T. Kaneko, Y. Tanji, S. Satoh, M. Hijikata, S. Asabe, K. Kimura, and K. Shimotohno, Biochem. Biophys. Res. Commun. 205:320-326, 1994). Both proteins have phosphorylated serine residues, some of which are located in the C-terminal region. In p58, phosphorylation of serine residues in the central region of HCV NS5A is important for production of p58 in an NS4A-dependent manner. To clarify the mechanism of NS5A phosphorylation, in particular phosphorylation in the central region, phosphorylation of deleted and mutated forms of NS5A was analyzed using a transient protein production system in cultured cells in the presence or absence of NS4A. Association of the NS5A region from amino acids 2135 to 2139 with NS4A was important for NS4A-dependent phosphorylation of NS5A.

Animals↗
PubMed1995

Bacterial expression and analysis of cleavage activity of HCV serine proteinase using recombinant and synthetic substrate.

HCV encoding serine proteinase was expressed in E. coli as a fused form with maltose binding protein (MBP) and a six histidine tag. The enzyme was partially purified by using affinity chromatography for these fused peptides. Proteolytic cleavage activity of the partially purified enzyme was detected by means of an assay using both a recombinant protein and a synthetic peptide substrate which had an amino acid sequence corresponding to the most efficient cleavage site in vivo, the NS5A-NS5B junction. The cleavage occurred at the same site that was reported before.

ATP-Binding Cassette Transporters↗
PubMed1995

Expression and processing of putative nonstructural proteins of hepatitis C virus in insect cells using baculovirus vector.

Processing of the putative nonstructural (NS) proteins, p70(NS3), p4(NS4A), p27(NS4B), p58/56(NS5A), and p66(NS5B), of Japanese type hepatitis C virus (HCV) in insect cells was analyzed by using a baculovirus expression system. Products processed by the HCV serine proteinase (Cpro-2) were essentially identical to those found in mammalian cultured cells transiently producing the NS region of the HCV precursor polyprotein. A series of internal and carboxy (C)-terminal deletion experiments coupled with epitope scanning analysis showed that efficient cleavage at the Cpro-2-dependent processing sites, except at the p4(NS4A)/p27(NS4B) site, is not significantly influenced by those mutations. Efficient cleavage at p4(NS4A)/p27(NS4B) required about 40% of the NS5A N-terminal region. Estimation of the processing sites by determination of the N-terminal amino acid sequences of the processed products revealed that all the Cpro-2-dependent cleavages occurred at essentially identical sites to those reported for another HCV genotype, suggesting that Cpro-2 is a possible target for the development of a strain-independent anti-HCV agent.

Amino Acid Sequence↗
PubMed1995

Hepatitis C virus-encoded nonstructural protein NS4A has versatile functions in viral protein processing.

A transient protein expression system in COS-1 cells was used to study the role of hepatitis C virus (HCV)-encoded NS4A protein on HCV nonstructural polyprotein processing. By analyzing the protein expression and processing of a deletion mutant polypeptide, NS delta 4A, which encodes the entire putative HCV nonstructural polyprotein except the region encoding NS4A, the versatile functions of NS4A were revealed. Most of the NS3 processed from NS delta 4A was localized in the cytosol fraction and was degraded promptly. Coproduction of NS4A stabilizes NS3 and assists in its localization in the membrane. NS4A was found to be indispensable for cleavage at the 4B/5A site but not essential for cleavage at the 5A/5B site in NS delta 4A. The functioning of NS4A as a cofactor for cleavage at the 4B/5A site was also observed when 30 amino acids around this site was used as a substrate and a serine proteinase domain of 167 amino acids, from Gly-1049 to Ser-1215, was used as an enzyme protein, suggesting that possible domains for the interaction of NS4A were in those regions of the enzyme protein (NS3) and/or the substrate protein. Two proteins, p58 and p56, were produced from NS5A. For the production of p58, equal or excess molar amounts of NS4A relative to NS delta 4A were required. Deletion analysis of NS4A revealed a minimum functional domain of NS4A of 10 amino acids, from Gly-1678 to Ile-1687.

Amino Acid Sequence↗
PubMed1995

Phosphorylation of hepatitis C virus-encoded nonstructural protein NS5A.

Two proteins, a 56-kDa protein (p56) and a 58-kDa protein (p58), are produced from the hepatitis C virus (HCV) nonstructural region 5A (NS5A). Recently, we found that both proteins are phosphorylated at serine residues and that p58 is a hyperphosphorylated form of p56. Furthermore, hyper-phosphorylation depends on the production of an intact form of the HCV NS4A protein. To clarify the nature of NS5A phosphorylation, pulse-chase analysis was performed with a transient protein production system in cultured cells. The study indicated that basal and hyperphosphorylation of NS5A occurred after proteolytic production of NS5A was complete. In an attempt to identify the location of the hyperphosphorylation sites in p58, proteins with sequential deletions from the C-terminal region of NS5A and with mutations of possible phosphorylated serine residues to a neutral amino acid, alanine, were constructed. The deleted or mutated proteins were then tested for hyperphosphorylation in the presence of the NS4A product. Here, we report that serine residues 2197, 2201, and/or 2204 are important for hyper-phosphorylation. Important sites for basal phosphorylation were identified in the region from residues 2200 to 2250 and in the C-terminal region of the NS5A product. A subcellular localization study showed that most of the NS5A products were localized in the nuclear periplasmic membrane fraction.

Amino Acid Sequence↗
PubMed1995

The N-terminal region of hepatitis C virus nonstructural protein 3 (NS3) is essential for stable complex formation with NS4A.

Hepatitis C virus proteins are produced by proteolytic processing of the viral precursor polyprotein that is encoded in the largest open reading frame of the viral genome. Processing of the nonstructural viral polyprotein requires the viral serine-type proteinase present in nonstructural protein 3 (NS3). The cleavage of the junction between NS4B and NS5A is mediated by NS3 only when NS4A is present. NS4A is thought to be a cofactor that enhances the cleavage efficiency of NS3 in hepatitis C virus protein-producing cells. Stable NS3-NS4A complex formation required the N-terminal 22 amino acid residues of NS3. This interaction contributed to stabilization of the NS3 product as well as increased the efficiency of cleavage at the NS4B/5A site. The N-terminal 22 amino acid residues fused to Escherichia coli dihydrofolate reductase also formed a stable complex with NS4A. NS3 derivatives which lacked the N-terminal 22 amino acid residues showed drastically reduced cleavage activity at the NS4B/5A site even in the presence of NS4A. These data suggested that the interaction with NS4A through the 22 amino acid residues of NS3 is primarily important for the NS4A-dependent processing of the NS4B/5A site by NS3.

Base Sequence↗
PubMed1995

Processing of the hepatitis C virus precursor protein.

Proteins of hepatitis C virus (HCV) are produced from a polyprotein precursor by post-translational processing. Production of HCV proteins was analyzed with in vitro translation, as well as plasmid-based transient gene expression, in mammalian cell lines. A minimum of three different processing pathways yielded at least 10 viral proteins from the polyprotein precursor. One pathway depended on signal protease processing, and the other two pathways utilized viral proteinases. The signal peptidase cleaved the viral structural proteins, and two viral activities broke up the viral nonstructural proteins. With staggered cleavages, the signal peptidase produced two E2 products from the E2 region, gp70 type A and type B, differing in the C-terminal structure. Two viral proteinases partially overlapped in the N-terminal region of NS3; the functional amino acid residues required for those two activities differed. Most of the processed viral proteins bound together; some of the associated proteins were membrane bound.

Amino Acid Sequence↗
PubMed1995

Processing of hepatitis C virus precursor polyprotein.

To elucidate the possible involvement of hepatitis C virus protein in the development of hepatocellular carcinoma. viral proteins produced from the largest open reading frame of the viral genome were analyzed. The function of each protein in virus replication was also examined. Virus proteins are produced by proteolytic cleavage by cellular and virus encoded proteinases. One of the viral proteins is a phosphoprotein, and the degree of phosphorylation is regulated by another viral protein. This regulation of phosphorylation may play an important role in modulating the proliferation of virus-infected cells.

Genome, Viral↗
PubMed1994

Production of two phosphoproteins from the NS5A region of the hepatitis C viral genome.

Hepatitis C virus produces about 12 viral proteins by proteolytic cleavage of the viral polyprotein precursor produced from the largest open reading frame in the viral genome. We have analyzed the production of viral nonstructural proteins with an in vivo transient expression system using COS-1 cells. Two proteins, a 56-kDa protein and a 58-kDa protein, were produced from the nonstructural region 5A (NS5A), which has the potential to produce a 49 kDa protein. We showed that these proteins are phosphorylated at the serine residues. The presence of the two proteins was reflected by different degrees of phosphorylation. Moreover, the hyper-phosphorylation of p58 was shown to depend on the presence of NS4A, another hepatitis C virus protein.

Animals↗