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M Hidaka

Publications and source records attributed to M Hidaka.

At least 37 records · Page 2Linked to original sources
PubMed2000

A hydrogen peroxide-forming NADH oxidase that functions as an alkyl hydroperoxide reductase in Amphibacillus xylanus.

The Amphibacillus xylanus NADH oxidase, which catalyzes the reduction of oxygen to hydrogen peroxide with beta-NADH, can also reduce hydrogen peroxide to water in the presence of free flavin adenine dinucleotide (FAD) or the small disulfide-containing Salmonella enterica AhpC protein. The enzyme has two disulfide bonds, Cys128-Cys131 and Cys337-Cys340, which can act as redox centers in addition to the enzyme-bound FAD (K. Ohnishi, Y. Niimura, M. Hidaka, H. Masaki, H. Suzuki, T. Uozumi, and T. Nishino, J. Biol. Chem. 270:5812-5817, 1995). The NADH-FAD reductase activity was directly dependent on the FAD concentration, with a second-order rate constant of approximately 2.0 x 10(6) M(-1) s(-1). Rapid-reaction studies showed that the reduction of free flavin occurred through enzyme-bound FAD, which was reduced by NADH. The peroxidase activity of NADH oxidase in the presence of FAD resulted from reduction of peroxide by free FADH(2) reduced via enzyme-bound FAD. This peroxidase activity was markedly decreased in the presence of oxygen, since the free FADH(2) is easily oxidized by oxygen, indicating that this enzyme system is unlikely to be functional in aerobic growing cells. The A. xylanus ahpC gene was cloned and overexpressed in Escherichia coli. When the NADH oxidase was coupled with A. xylanus AhpC, the peroxidase activity was not inhibited by oxygen. The V(max) values for hydrogen peroxide and cumene hydroperoxide reduction were both approximately 150 s(-1). The K(m) values for hydrogen peroxide and cumene hydroperoxide were too low to allow accurate determination of their values. Both AhpC and NADH oxidase were induced under aerobic conditions, a clear indication that these proteins are involved in the removal of peroxides under aerobic growing conditions.

Amino Acid Sequence↗
PubMed2000

Early development of zooxanthella-containing eggs of the corals Pocillopora verrucosa and P. eydouxi with special reference to the distribution of zooxanthellae.

Some hermatypic corals spawn eggs that contain zooxanthellae. We followed development of zooxanthella-containing eggs of two such species, Pocillopora verrucosa and P. eydouxi. We also documented changes in the distribution pattern of zooxanthellae during development. Oocytes of both species took up zooxanthellae 3 to 4 days before spawning. At first, zooxanthellae were evenly distributed in oocytes, but they later moved to the hemisphere that contained the germinal vesicle. After fertilization, early cleavage events were holoblastic, progressing by furrow formation. The first cleavage furrow started at the hemisphere that contained zooxanthellae, dividing the zooxanthellate complement of the zygote about equally into the two blastomeres. The second division divided each blastomere into one zooxanthellae-rich cell and one with few zooxanthellae. With continued cell division, blastomeres containing zooxanthellae moved into the blastocoel. The blastocoel disappeared at about 5 h after the first cleavage, and the central region of the embryo was filled with cells containing either zooxanthellae or lipid droplets, forming a stereogastrula. Our results suggest that only blastomeres that had been determined to develop into gastrodermal cells receive zooxanthellae during cleavage. This determination appears to take place, at the latest, by the second cell division at the four-cell stage.

Animals↗
PubMed2000

[Measurement of fecal proteins in inflammatory bowel disease--usefulness as an activity index].

Fecal alpha 1-antitrypsin (alpha 1-AT), alpha 2-macroglobulin (alpha 2-M), lysozyme (Lz), and lactoferrin (Lf) levels were measured in 73 samples from 32 patients with ulcerative colitis (UC), 52 samples from 21 patients with Crohn's disease (CD), and 41 samples from 21 healthy volunteers. According to three degree of bowel activity, the UC patients were divided into 4 groups and the CD patients were divided into 2 groups. Fecal alpha 1-AT levels were measured by latex agglutination and the other protein parameters by ELISA. All protein levels, except alpha 1-AT, rose as the degree of activity increased. The fecal protein markers alpha 2-M, LZ, and Lf had significantly higher positive rates than the serum inflammatory markers and activity index in the moderate and severe UC groups, and alpha 2-M and Lf had significantly higher rates in the CD (+) group. Based on these findings measurement of fecal levels on alpha 2-M, LZ, and Lf appeared to be useful activity markers for UC, and alpha 2-M and Lf for CD.

Adult↗
PubMed2000

A novel type of factor XI deficiency showing compound genetic abnormalities: a nonsense mutation and an impaired transcription.

We studied a 29-year-old Japanese male patient with factor XI deficiency; we also studied his parents and one sibling. Factor XI coagulation activity and antigen levels were extremely low (less than 1% of normal level) in both the patient and his brother, and they were half the normal levels in both parents. Sequence analysis of all 15 exons and the exon-intron boundaries of the factor XI gene amplified by polymerase chain reaction revealed a nonsense mutation in exon 8 (Gln263-->Stop). Although the parents are first cousins, the mutation was unexpectedly heterozygous in all the family members except the father, who showed the homozygous wild type, indicating that this mutation alone was not sufficient to account for the factor XI deficiency. To explore the genetic abnormality in the father, we analyzed allele-specific expression of the platelet factor XI gene using reverse transcription-polymerase chain reaction and subsequent restriction enzyme digestion. As a result, gene expression from only one allele was severely impaired in the father. This result implies an additional mutation in some regulatory element of the factor XI gene from paternal inheritance. We concluded that the factor XI deficiency of the patient was caused by compound heterozygous genetic abnormalities.

Adult↗
PubMed2000

Two cases showing clonal progression with full evolution from aplastic anemia-paroxysmal nocturnal hemoglobinuria syndrome to myelodysplastic syndromes and leukemia.

We report 2 paroxysmal nocturnal hemoglobinuria (PNH) patients who were initially diagnosed with aplastic anemia and sequentially developed PNH, myelodysplastic syndromes (MDS), and leukemia. Flow cytometry and cytogenetic analysis showed the initial appearance and expansion of PNH clones, gradual replacement of PNH clones by MDS clones with monosomy 7, and then expansion of MDS clones or their subclones with additional chromosomal abnormalities. In relation to these developments, expression increased of the Wilms' tumor gene WT1, a marker for leukemic progression. These patients not only shared bone marrow failure but also might have harbored a hematopoietic environment favorable for the emergence of abnormal clones leading to leukemogenesis.

Adult↗
PubMed1999

Conditional requirement for the Flk-1 receptor in the in vitro generation of early hematopoietic cells.

Genetic studies in mice have previously demonstrated an intrinsic requirement for the vascular endothelial growth factor (VEGF) receptor Flk-1 in the early development of both the hematopoietic and endothelial cell lineages. In this study, embryonic stem (ES) cells homozygous for a targeted null mutation in flk-1 (flk-1 (-/-)) were examined for their hematopoietic potential in vitro during embryoid body (EB) formation or when cultured on the stromal cell line OP9. Surprisingly, in EB cultures flk-1 (-/-) ES cells were able to differentiate into all myeloid-erythroid lineages, albeit at half the frequency of heterozygous lines. In contrast, although flk-1 (-/-) ES cells formed mesodermal-like colonies on OP9 monolayers, they failed to generate hematopoietic clusters even in the presence of exogenous cytokines. However, flk-1 (-/-) OP9 cultures did contain myeloid precursors, albeit at greatly reduced percentages. This defect was rescued by first allowing flk-1 (-/-) ES cells to differentiate into EBs and then passaging these cells onto OP9 stroma. Thus, the requirement for Flk-1 in early hematopoietic development can be abrogated by alterations in the microenvironment. This finding is consistent with a role for Flk-1 in regulating the migration of early mesodermally derived precursors into a microenvironment that is permissive for hematopoiesis.

Animals↗
PubMed1999

Comparison of gene structures and enzymatic properties between two endoglucanases from Humicola grisea.

We have cloned two endoglucanase genes (egl3 and egl4) from a thermophilic fungus, Humicola grisea. The coding region of the egl3 gene was interrupted by an intron of 56-bp, and the deduced amino acid sequence of the egl3 gene was 305 amino acids in length and showed 98.4% identity with Humicola insolens EGV. The coding region of the egl4 gene was also interrupted by an intron of 173-bp, which contains 34 TTC repeated sequence units, and the deduced amino acid sequence of the egl4 gene was 227 amino acids in length and showed 61.5% identity with H. grisea EGL3. The typical hinge and the cellulose-binding domain were observed in the C-terminal region of EGL3, but they were not observed in EGL4. In the 5' upstream region of both genes, there were a TATA box or its similar sequence, CAAT motifs, and 6-bp sites which are identical or similar to the consensus sequence for binding a catabolite repressor CREA in Aspergillus nidulans. The egl3 and the egl4 genes were expressed in Aspergillus oryzae, and the translation products were purified. The fusion protein, EGL4CBD, which consists of a catalytic domain of EGL4 and the C-terminal region of EGL3, was also constructed and produced by A. oryzae, and purified. These enzymes showed relatively high activity toward carboxymethyl cellulose (CMC) and could not hydrolyze p-nitrophenyl-beta-D-glucoside and p-nitrophenyl-beta-D-cellobioside. The positive effect of substituting the C-terminal region of EGL4 with that of EGL3 was observed in the hydrolysis of CMC.

Amino Acid Sequence↗
PubMed1999

Neuroendoscopic surgery for specific forms of hydrocephalus.

Neuroendoscopic surgery was used to treat patients with various forms of hydrocephalus with specific pathophysiology, including long-standing overt ventriculomegaly in adulthood (LOVA), isolated unilateral hydrocephalus (IUH), isolated IV ventricle (IFV), disproportionately large IV ventricle (DLFV), isolated rhombencephalic ventricle (IRV), isolated quarto-ventriculomegaly (IQV), dorsal sac in holoprosencephaly (DS), and loculated ventricle (LV). A total of 26 operative procedures were performed, with neuroendoscopic surgery in 22 patients, 12 with unique forms of noncommunicating hydrocephalus and 10 with various types of postshunt isolated compartment. These procedures included III ventriculostomy, aqueductal plasty by both rostral and caudal approaches, foraminal plasty in the foramen of Monro/foramen of Magendie, septostomy, IV ventriculostomy, fenestration of septation in the loculated ventricle, fenestration of arachnoid cyst or cystic tumor obstructing a ventricle with or without tumor removal, and dorsal sac ventriculostomy. The characteristics of the cerebrospinal fluid (CSF) dynamics in the individual specific pathophysiologies were delineated by cardiac-gated cine-mode magnetic resonance imaging (MRI) before and after the endoscopic procedure. The consequent success rate (success = restoration of communication of the CSF pathway in the individual patients) was 19/22 (86.4%). The progression of ventricular dilatation was stopped in 17 of 19 patients (89.5%) in whom the endoscopic procedure was successful (radiologically arrested hydrocephalus). Improvement in the clinical symptoms and signs (clinically arrested hydrocephalus) was obtained in 15 of the patients (68.2% of all patients: 5 with LOVA, 3 with IQV, 5 with IUH and 2 with LV). Seven patients (2 LOVA, 2 IFV, 1 DS, 1 DFLV and 1 IRV) underwent a shunt procedure after the neuroendoscopic procedure(s). The postoperative changes of ventriculomegaly were complicated, reflecting the differences in the brain parenchymal compliance and postoperatively corrected CSF flow dynamics in the major CSF pathway.

Adult↗
PubMed1999

A new experimental model of obstructive hydrocephalus in the rat: the micro-balloon technique.

We used three types of specialized micro-balloons 0.7-1.35 mm in outer diameter instead of kaolin to develop a reproducible rat model of hydrocephalus with a low experimental mortality. The micro-balloon was inserted 6 mm deep into the cisterna magna via a burr hole immediately behind the lambda. The angle of introduction was 50 degrees. We also set up kaolin-induced hydrocephalic models in 25 rats as controls. The kaolin model revealed 52% mortality with an 80% induction rate of hydrocephalus, while the balloon model showed 9% mortality with a 60% induction rate. Balloon-induced hydrocephalus was maximal at 1 week and tended to decrease after 2-3 weeks. The pathological findings were not different between the two models. We concluded that the micro-balloon model for hydrocephalus is an easily reproducible model with low experimental mortality.

Animals↗
PubMed1999

Molecular cloning and expression of the novel fungal beta-glucosidase genes from Humicola grisea and Trichoderma reesei.

A novel fungal beta-glucosidase gene (bgl4) and its homologue (bgl2) were cloned from the cellulolytic fungi Humicola grisea and Trichoderma reesei, respectively. The deduced amino acid sequences of H. grisea BGL4 and T. reesei BGL2 comprise 476 and 466 amino acids, respectively, and share 73.1% identity. These beta-glucosidases show significant homology to plant beta-glucosidases belonging to the beta-glucosidase A (BGA) family. Both genes were expressed in Aspergillus oryzae, and the recombinant beta-glucosidases were purified. Recombinant H. grisea BGL4 is a thermostable enzyme compared with recombinant T. reesei BGL2. In addition to beta-glucosidase activity, recombinant H. grisea BGL4 showed a significant level of beta-galactosidase activity, while recombinant T. reesei BGL2 showed weak beta-galactosidase activity. Cellulose saccharification by Trichoderma cellulases was improved by the addition of recombinant H. grisea BGL4.

Amino Acid Sequence↗
PubMed1999

Isolation and characterization of the actin gene from the cellulolytic fungus Humicola grisea and analysis of transcription levels of actin and cellulase genes.

An actin gene was isolated from the cellulolytic fungus Humicola grisea. The gene structure, which has 5 introns in the coding region, is similar to those of the so far cloned fungal actin genes. But there are some differences in intron sizes and codon usage. Transcription levels of actin and cellulase genes were also investigated.

5' Untranslated Regions↗
PubMed1999

Inhibitory effect of free sialic acid on complement activation and its significance in hypocomplementemic glomerulonephritis.

The role of free sialic acid on complement activation was investigated. The serum levels of free sialic acid and total sialic acid were measured by previously described methods in 16 patients with acute post-infectious glomerulonephritis (AGN), 27 patients with systemic lupus erythematosus (SLE), 15 patients with persistent hypocomplementemic membranoproliferative glomerulonephritis (MPGN), and 13 healthy controls. A statistical study demonstrated an increased level of free sialic acid in patients with AGN and SLE in which the hypocomplementemia improved throughout the course and a decreased level of free sialic acid in patients with MPGN and SLE in which hypocomplementemia continued throughout the course. The levels of total sialic acid were significantly increased in patients with AGN and SLE and were significantly decreased in patients with MPGN. There was no correlation between the levels of free sialic acid and total sialic acid in patients with AGN, in whom the levels of both total and free sialic acids were increased. To examine the effect of free sialic acid on the complement cascade, lipopolysaccharide (LPS) was incubated with normal human serum (NHS) in the various concentrations of N-acetyl neuraminic acid (NANA), a member of the sialic acid group. The incubation mixtures were examined by enzyme immunoassay using monoclonal anti-iC3b antibody or anti-Bb antibody. Native C3 or Factor B in NHS broke down less following the addition of NANA. To elucidate the role of NANA on the hemolytic function of C3, a rabbit erythrocyte (Ra E) hemolytic assay was carried out. Ra E lysed completely in the presence of R3 with native C3. However, hemolysis occurred to a lesser degree in C3-depleted serum (R3) or R3 with NANA-treated C3. To investigate the influence of NANA on complement components, the levels of complement components were measured in the incubation mixture with various doses of NANA and NHS. The levels of C3 and C5 were significantly decreased after the addition of NANA, even though the levels of Factor H and Factor I were not markedly changed. These data indicate that NANA exerts an influence on the complement components even though it has no effect on the regulatory proteins of complement. Our in vitro findings, together with the in vivo data, suggest that free sialic acid might have an inhibitory effect on the activation of C3 and the following complement cascade, and might also have been responsible for the improvement of hypocomplementemia.

Animals↗
PubMed1999

[Three cases of pregnancy in primary glomerulonephritis with successful outcomes in spite of severe histological findings].

When women with kidney disease wish to have children, concerns are raised about the adverse effect on their renal function. Although the situation is less clear in regard to the effects, there is general agreement that a moderately severe decrease in renal function, especially in the presence of significant hypertension, reduces the chance of conception, and a successful outcome of gestation. On the other hand, several reports maintain that in most patients, pregnancy does not change the natural history of glomerular disease. Accordingly, we reported successful cases in whom renal function remained preserved. The three cases suffered from different types of glomerulonephritis (GN) and percutaneous renal biopsies were conducted before pregnancy. All biopsy specimens were examined by light and immunofluorescence microscopy, and were diagnosed as IgA nephropathy, sclerosing GN and membranoproliferative GN, respectively. Since severe histological findings were found and their data worsened (serum creatinine > 1.3 mg/dl, 24-hr creatinine clearance < 70 ml/min), their chance of having children appeared low. However, as we did not observe deterioration of clinical findings and hypertension over the ten-year follow-up, we allowed conception resulting in the birth of normal children. Thus we should mention the relatively favourable courses of nephropathy in some patients with GN, particularly in patients with stable renal disease and normal blood pressure, it should not be considered an indication for termination. It is important to observe the status of glomerular disease for as long as possible.

Adult↗
PubMed1999

[Catalase (CAT)].

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Catalase↗
PubMed1998

Expression trapping: identification of novel genes expressed in hematopoietic and endothelial lineages by gene trapping in ES cells.

We have developed a large-scale, expression-based gene trap strategy to perform genome-wide functional analysis of the murine hematopoietic and vascular systems. Using two different gene trap vectors, we have isolated embryonic stem (ES) cell clones containing lacZ reporter gene insertions in genes expressed in blood island and vascular cells, muscle, stromal cells, and unknown cell types. Of 79 clones demonstrating specific expression patterns, 49% and 16% were preferentially expressed in blood islands and/or the vasculature, respectively. The majority of ES clones that expressed lacZ in blood islands also expressed lacZ upon differentiation into hematopoietic cells on OP9 stromal layers. Importantly, the in vivo expression of the lacZ fusion products accurately recapitulated the observed in vitro expression patterns. Expression and sequence analysis of representative clones suggest that this approach will be useful for identifying and mutating novel genes expressed in the developing hematopoietic and vascular systems.

Animals↗
PubMed1998

Overproduction of recombinant Trichoderma reesei cellulases by Aspergillus oryzae and their enzymatic properties.

We have established an expression system of Trichoderma reesei cellulase genes using Aspergillus oryzae as a host. In this system, the expression of T. reesei cellulase genes were regulated under the control of A. oryzae Taka-amylase promoter and the cellulase genes were highly expressed when maltose was used as a main carbon source for inducer. The production of recombinant cellulases by A. oryzae transformants reached a maximum after 3-4 days of cultivation. In some cases, proteolysis of recombinant cellulases was observed in the late stage of cultivation. The recombinant cellulases were purified and characterized. The apparent molecular weights of recombinant cellulases were more or less larger than those of native enzymes. The optimal temperatures and pHs of recombinant cellulases were 50-70 degrees C and 4-5, respectively. Among the recombinant cellulases, endoglucanase I showed broad substrate specificities and high activity when compared with the other cellulases investigated here.

Aspergillus oryzae↗