Biomedical subjects

S Hongo

Publications and source records attributed to S Hongo.

At least 19 recordsLinked to original sources

PubMed1992

Immunochemical characterization of rat testicular asparagine synthetase.

We studied immunochemical properties of rat testicular asparagine synthetase. Western blot analysis of testis extract with polyclonal antibody raised against purified asparagine synthetase revealed an immunoreactive band at 62 kDa. The pancreas, brain, thymus, and spleen also showed 62-kDa bands. The intensities of these bands were roughly proportional to the specific activities of the enzyme in these tissues. The antibody showed some degree of cross-reactivity to asparagine synthetases from human, beef, pig, mouse, guinea pig, chicken, and frog, but not carp. But the enzyme from human HL-60 cells and lower vertebrates reacted with the antibody less strongly than enzyme from rats. The N-terminal amino acid sequence of the enzyme, determined by the Edman degradation method, in 10 recovered residues was identical to that of human asparagine synthetase deduced from corresponding cDNA (I.L. Andrulis et al., 1987, Mol. Cell. Biol. 7, 2435-2443). Immunohistochemical staining of the testis showed the presence of asparagine synthetase mainly in Sertoli cells in the seminiferous tubules.

Amino Acid Sequence↗

PubMed1992

Cloning and sequencing of influenza C/Yamagata/1/88 virus NS gene.

It was previously shown that the shortest RNA of influenza C/California/78 virus contains 934 nucleotides and codes for two nonstructural proteins of 286 amino acids (NS 1) and 121 amino acids (NS 2). In this report, we determined the nucleotide sequence of the NS gene of the recently isolated influenza C/Yamagata/1/88 strain by using cloned cDNA derived from the viral RNA. Compared with the NS gene of C/California/78, one nucleotide insertion has occurred in the NS gene of C/Yamagata/1/88. This caused frame shifts of both the NS 1 and NS 2 reading frames, directing the synthesis of the NS 1 and NS 2 proteins consisting of 246 and 182 amino acids, respectively.

Amino Acid Sequence↗

PubMed1992

Protective effect of serum antibody on respiratory infection of influenza C virus in rats.

The effects of serum antibody on the replication of influenza C virus in the nose and lung were evaluated in rats challenged with the virus by the intranasal and endotracheal routes, respectively. Convalescent rat serum administered intraperitoneally prior to infection suppressed virus replication significantly in both the nasal and pulmonary tissues. Resistance achieved was however much greater in the lung than in the nose. Rats with a serum neutralizing antibody titer of 1:800 showed almost complete resistance to pulmonary virus infection, and virus yield from the lung was reduced 10- to 100-fold in animals with the antibody titer of 1:80-160 or less. In contrast, significant decrease in virus shedding from the nose was observed only in animals with a serum antibody titer of 1:800 or greater. The effect of adoptive transfer of monoclonal antibodies (MAbs) to haemagglutinin-esterase (HE) glycoprotein and matrix (M) protein on pulmonary virus replication was also examined. Anti-HE MAbs with neutralization activity prevented virus shedding from the lung almost completely whereas non-neutralizing anti-HE MAb and anti-M Mab showed no inhibitory effect.

Animals↗

PubMed1992

Selection of antigenically distinct variants of influenza C viruses by the host cell.

Five strains of influenza C virus were isolated and passaged in the amniotic sacs of embryonated hens' eggs, or in the HMV-II line of human malignant melanoma cells, and were tested for reactivity with a panel of monoclonal antibodies to the hemagglutinin-esterase (HE) glycoprotein. It was observed with two strains (C/Yamagata/4/88, C/Yamagata/7/88) that the HE of virus passaged in HMV-II cells was antigenically distinguishable from that of virus cultivated in eggs. Virus clones obtained after repeated passages of these two strains in HMV-II cells all showed a significant increase in the ability to replicate in the cell culture compared to clones derived from viruses grown in eggs. No difference was seen, by contrast, in the ability to grow in eggs between HMV-II- and egg-derived virus clones. It was also found that HMV-II-grown viruses but not egg-grown viruses could agglutinate glutaraldehyde-fixed chicken erythrocytes at 23 degrees. These observations, taken together, suggest that isolation and passage of influenza C virus in HMV-II cells sometimes result in selection of antigenically distinct variants which have an advantage in binding to the cell surface receptors. Sequence analyses of the HE genes revealed that compared to egg-grown viruses, HMV-II-adapted variant of the Yamagata/4/88 strain had a single amino acid substitution in the HE molecule at position 283 (Asp----Asn) and that of the Yamagata/7/88 strain had two substitutions at positions 212 (Glu----Lys) and 519 (Asn----Asp).

Animals↗

PubMed1992

Location of neutralizing epitopes on the hemagglutinin-esterase protein of influenza C virus.

Neutralization-resistant variants of influenza C/Ann Arbor/1/50 virus were selected with monoclonal antibodies against four different antigenic sites on the hemagglutinin-esterase (HE) glycoprotein, and their HE genes were sequenced to identify amino acid residues important for the integrity of each site. Twelve different amino acid substitutions in a total of 18 antigenic variants were all located on the HE1 subunit. Although variants for antigenic site A-2 had a change at position 367, all substitutions in the variants for sites A-1, A-3, and A-4 occurred in the central region of the HE1 spanning amino acid positions 178 to 283. Furthermore, it was found that many of the substitutions in the variants selected with antibodies to sites A-1 and A-3 were clustered within or near one of the three variable regions revealed previously by comparing amino acid sequences of the HEs among various influenza C isolates (Buonagurio, D. A., Nakada, S., Fitch, W. M., and Palese, P., Virology 146, 221-232, 1985). The antigenic variants were also examined for their ability to agglutinate chicken and human erythrocytes in order to obtain information concerning the receptor-binding site on the HE molecule. The results suggested that the amino acid changes at residues 178, 186, 187, 190, 206, 212, and 226 decreased the hemagglutinating activity whereas those at residues 245, 266, and 283 produced an opposite effect.

Amino Acid Sequence↗

PubMed1992

Antigenic and genetic analyses of eight influenza C strains isolated in various areas of Japan during 1985-9.

Eight strains of influenza C virus isolated in various areas of Japan between January 1985 and January 1989 were compared using monoclonal antibodies to the haemagglutinin-esterase (HE) glycoproteins and by oligonucleotide mapping of total vRNA. Five of six strains isolated during 1986-9 were closely related to one another and also resembled the virus, C/Aichi/1/81, isolated in 1981 in Aichi prefecture. This suggests that the C/Aichi/1/81-related viruses had an epidemiological advantage over any co-circulating viruses at least during that period. One of two 1985 isolates (C/Nara/1/85) was antigenically indistinguishable from the C/Mississippi/1/80 strain though their oligonucleotide patterns were markedly different from each other. This raises the possibility that C/Nara/1/85 may be a recombinant virus which receives its HE gene from the C/Mississippi/1/80-related parent.

Antigens, Viral↗

PubMed1992

Daily intakes of 232Th and 238U in Japanese males.

Diet samples were collected by a duplicate portion method from 31 locations in Japan and were analyzed by inductively coupled plasma mass spectrometry. Average daily intakes per adult male were estimated at 1.7 mBq for 232Th and 8.8 mBq for 238U.

Adult↗

PubMed1991

Translational discrimination of ribosomal protein mRNAs in the early Drosophila embryo.

Most Drosophila mRNAs are actively translated in the early embryo, with the exception of the poorly translated ribosomal protein (r-protein) mRNAs. Two possible mechanisms for this translational discrimination were tested: (1) Translation of r-protein mRNAs is discriminated against by the limited activity of translational initiation factors in the early embryo and (2) translation of r-protein mRNAs is repressed by trans-acting factors that reversibly bind these mRNAs. Exogenously provided initiation factors promoted partial recruitment of r-protein mRNAs into polysomes, suggesting that modulation of initiation factor activity may play a role in the translational discrimination of r-protein mRNAs during embryogenesis. No evidence for involvement of reversibly binding trans-acting factors was obtained, although there are limitations in the interpretation of the latter experiments.

Actins↗

PubMed1991

Antigenic characterization of the nucleoprotein and matrix protein of influenza C virus with monoclonal antibodies.

Monoclonal antibodies against the nucleoprotein (NP) and matrix (M) protein of influenza C virus were prepared and characterized. At least two non-overlapping or partially overlapping antigenic sites were delineated on each of the proteins by competitive binding assays. Western blot analysis showed that two antigenic sites on the M protein were highly resistant to conformational changes whereas two sites on NP were sensitive. No antigenic variation was seen in either the NP or the M protein when the reactivity of monoclonal antibodies with 23 different influenza C strains isolated over a 41 year period was studied by radioimmunoprecipitation and enzyme-linked immunosorbent assay. Immunofluorescence analysis with the monoclonal antibodies revealed that both the NP and M proteins migrated to the cell nucleus during the replication cycle of influenza C virus.

Animals↗

PubMed1990

Decrease in asparagine synthetase activity during cell differentiation of mouse and human leukemia cell lines.

The activity of asparagine synthetase decreased almost 50% during dexamethasone-induced mouse myeloid leukemia M1 cell differentiation. This enzyme activity also declined significantly during differentiation of the human myelogenous leukemic cell lines, HL-60 and U-937, induced by either macrophage culture supernatant or retinoic acid. The decline of asparagine synthetase activity closely paralleled the expression of various maturation markers, but could also be induced by serum starvation. These results suggest that asparagine synthetase or L-asparagine has some biological function in growth regulation of these leukemia cell lines.

Animals↗

PubMed1989

[Evaluation of excised loach skin for studies on transdermal permeation of drugs in vitro].

Transdermal permeation of drug across the excised skin of Asian pond loach (Misgurnus anguillicaudatus Cantor) was studied in vitro. Ten kinds of drugs, D-glucose, L-glucose, sucrose, salicylic acid, cefazolin, urea, antipyrine, naphazoline, propranolol and enviomycin were permeated through the excised loach skin, whereas dextran, a polysaccharide, could not be permeated through the skin. The observed transdermal flux (J), the slope of the line obtained from plots of the cumulative amount of drug permeated vs. time, increased as the drug concentration in the donor compartment solution (50----300 mM), as the temperature of the skin (test solution) increased (4----37 degrees C), or as the molecular weight of compound decreased. These results suggested that the transport of drug across the loach skin was due to the passive diffusion mechanism. The effect of pH on the permeation of drug could not be elucidated since the loach skin was drastically impaired below pH 5.0. The J values of antipyrine and naphazoline varied in proportion to the drug concentration in the donor compartment solution at time zero (C0). The permeability constants (Kp, cm.h-1) of antipyrine and naphazoline were 12.9 x 10(-2) and 9.2 x 10(-2), respectively. However, the J values of salicylic acid and urea were not proportional to C0 in high concentration (300 mM). Probably, these results were related to the irritative effect of salicylic acid or urea on the skin.

Animals↗

PubMed1989

Induction of asparagine synthetase during lymphocyte activation by phytohemagglutinin.

Asparagine synthetase was increased in cultured mouse spleen lymphocytes after stimulation by phytohemagglutinin. After a lag period of about 24h, the enzyme activity level rose sharply by 48h, reached its maximum at 72h, and decreased thereafter. The time course of the change in the enzyme activity was similar to that of the change in the rate of DNA synthesis. From the results that there was no increase of the activity of asparagine synthetase at the time induction of ornithine decarboxylase would occur (6h), it seems unlikely that asparagine synthesized in the cells contributes to the enhancement of ornithine decarboxylase during the activation of lymphocytes. The increase of asparagine synthetase activity was inhibited by cycloheximide and somewhat by actinomycin D, suggesting de novo enzyme synthesis during the stimulation.

Animals↗

PubMed1988

Antisense ribosomal protein gene expression specifically disrupts oogenesis in Drosophila melanogaster.

To assess the functional importance of ribosomal protein rpA1 gene expression during development of Drosophila melanogaster, we have transformed into the fly's genome an antisense rpA1 gene driven by a heat shock promoter. Antisense rpA1 expression severely disrupted oogenesis and produced a "small egg" female-sterile phenotype. The severities of these defects were proportional to the level of antisense rpA1 expression. Anti-rpA1 expression did not affect larval or pupal development. Quantitative RNA analysis suggested that high anti-rpA1 expression results in a general decrease of mRNA in the ovary.

Animals↗

PubMed1986

The functions of oligosaccharide chains associated with influenza C viral glycoproteins. I. The formation of influenza C virus particles in the absence of glycosylation.

The effect of a glycosylation inhibitor, tunicamycin (TM) on the replication of influenza C virus was investigated. Incorporation of [3H]-glucosamine into the gp88 glycoproteins of this virus was completely inhibited by TM at the concentrations higher than 0.25 microgram/ml. Under these conditions, the synthesis of internal proteins NP and M was shown in TM-treated cells but the synthesis of gp88 was not. The disappearance of gp88 was however accompanied with the appearance of two new polypeptides with molecular weights of 80,000 (T80) and 76,000 (T76). While T80 was identified by peptide mapping as a host cell protein whose synthesis was enhanced by TM, T76 was shown to correspond to a nonglycosylated form of gp88. Pulse-chase experiments revealed that there was no significant difference in the intracellular stability of T76 and gp88. Although TM depressed the production of infectious progeny virus greater than 100-fold, only a five-fold decrease was observed in the release of noninfectious physical particles, suggesting that glycosylation is not essential for the formation of influenza C virus particles. However, the virions from TM-treated cells had a lower buoyant density in isopycnic sucrose gradients and lacked surface proteins in either glycosylated or nonglycosylated form.

Amnion↗

PubMed1986

The functions of oligosaccharide chains associated with influenza C viral glycoproteins. II. The role of carbohydrates in the antigenic properties of influenza C viral glycoproteins.

The antigenic properties of influenza C viral glycoprotein gp88 were compared with those of its nonglycosylated counterpart T76 synthesized in infected cells treated with tunicamycin. Radioimmunoprecipitation experiments with three different monoclonal antibodies against gp88 revealed that an antibody designated Q-5 precipitated gp88 but not T76, indicating the requirement for glycosylation for the binding of this antibody to gp88. It is unlikely, however, that the antigenic determinant recognized by Q-5 is carbohydrate moiety since the ability of the antibody to bind to gp88 varied depending on the virus strain, and trypsin-treatment of gp88 eliminated its reactivity with Q-5. Gel electrophoretic analysis under nonreducing conditions showed that T76 underwent the formation of disulfide-linked multimers in the absence of reducing agent while gp88 behaved as monomers, suggesting that glycosylation is required for gp88 molecules to attain an appropriate conformation. These observations, altogether, suggests that glycosylation is important in determining the immunological specificity of gp88 presumably by influencing the folding of this glycoprotein.

Amnion↗

PubMed1986

Identity of rat liver mitochondrial asparagine-pyruvate transaminase with phenylalanine-pyruvate transaminase.

Identification of rat liver mitochondrial asparagine-pyruvate transaminase with phenylalanine-pyruvate transaminase has been done. When a mitochondria extract was subjected to isoelectric focusing, the two enzyme activities were identically focused. This procedure and DEAE-Sepharose chromatography revealed multiple forms of the enzyme, in which the main form was purified. In the various purification steps the two enzyme activities appeared in the same fraction. The enzyme of the final preparation step gave a single band in polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. During the purification, a similar increase of the specific activity and yield were obtained in the two activities. Phenylalanine was found to be a competitive inhibitor of asparagine transaminase. These results suggest the identity of the two enzymes.

Animals↗

PubMed1985

Kinetic studies of asparagine synthetase from rat liver: role of Mg2+ in enzyme catalysis.

The kinetic mechanism of asparagine synthetase from rat liver has been studied. The mechanism of the reaction in the presence of high concentrations of total Mg2+ (50 mM) was suggested to be a uni-uni-bi-ter ping-pong-type without abortive complexes; glutamine binds first followed by glutamate release, and aspartate and ATP bind in order followed by ordered release of PPi, AMP, and asparagine. But, it is indicated that in the presence of 0.5-2.0 mM excess Mg2+ over ATP the binding of substrates after the release of glutamate is in a rapid equilibrium system such as ordered Mg2+ and random aspartate-MgATP. Mg2+ was demonstrated to have two roles in the catalysis; to modify the enzyme and to form a complex of MgATP.

Adenosine Triphosphate↗

PubMed1985

Effects of glycosylation on the conformation and antigenicity of influenza C viral glycoproteins.

The antigenicity of influenza C viral glycoprotein gp88 was compared with that of its non-glycosylated counterpart T76 by immunoprecipitation utilizing monoclonal antibodies against gp88. Of the three monoclonal antibodies tested, an antibody designated Q-5 was found to precipitate gp88 but not T76, indicating the requirement for glycosylation for the binding of Q-5 to gp88. However, the antigenic determination recognized by Q-5 did not appear to be carbohydrates since trypsin-treatment of gp88 eliminated its reactivity with this antibody. These results suggest that glycosylation is important in determining the antigenicity of gp88 presumably by influencing the folding of the glycoproteins.

Antibodies, Monoclonal↗