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K Kitamoto

Publications and source records attributed to K Kitamoto.

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

Characterization of a novel fungal protein, p15, which induces neuronal differentiation of PC12 cells.

In our previous paper, we reported that a 15 kDa protein (p15) produced by a fungus, genus Helicosporium, enhanced NGF-induced neurite outgrowth from PC12 cells. Here we further characterized the actions of p15. The complete amino acid sequence of p15 was determined and it was shown to be a hydrophilic protein composed of 118 amino acid residues with two intramolecular disulfide bridges. p15-induced neurite outgrowth was blocked by the depletion of extracellular Ca(2+) in the culture medium and was significantly inhibited by L-type Ca(2+) channel inhibitor nicardipine. p15 stimulated Src kinase and MAPK activities, and neurite outgrowth was not observed in srcDN2, a dominant negative c-src(K295R)-expressing cell line, and was significantly reduced in RasN17-expressing cells. These results suggest that p15 stimulates neurite outgrowth through the potentiation of L-type Ca(2+) channels, thereby activating the Src-Ras-MAPK cascade.

Amino Acid Sequence↗
PubMed1999

Insertion analysis of putative functional elements in the promoter region of the Aspergillus oryzae Taka-amylase A gene (amyB) using a heterologous Aspergillus nidulans amdS-lacZ fusion gene system.

Expression of the Taka-amylase A gene (amyB) of Aspergillus oryzae is induced by starch or maltose. The A. oryzae amyB gene promoter contains three highly conserved sequences, designated Regions I, II, and III, compared with promoter regions of the A. oryzae glaA encoding glucoamylase and the agdA encoding alpha-glucosidase. To identify the function of these sequences within the amyB promoter, various fragments containing conserved sequences in the amyB promoter were introduced into the upstream region of the heterologous A. nidulans amdS gene (encoding acetamidase) fused to the Escherichia coli lacZ gene as a reporter. Introduction of the sequence between -290 to -233 (the number indicates the distance in base pairs from the translation initiation point (+1)) containing Region III significantly increased the expression of the lacZ reporter gene in the presence of maltose. The sequence between -377 to -290 containing Region I also increased the lacZ activity, but its maltose inducibility was less than that of Region III. The sequence between -233 to -181 containing Region II had no effect on the expression. These results indicated that Region III is most likely involved in the maltose induction of the amyB gene expression.

Amidohydrolases↗
PubMed1999

Hypoalbuminemia accelerates erythrocyte membrane lipid peroxidation in chronic hemodialysis patients.

BACKGROUND: Persistent hypoalbuminemia is a long-term poor prognostic factor in chronic hemodialysis patients. PATIENTS AND METHODS: We investigated the correlation between the degree of peroxidation of erythrocyte membrane lipids, erythrocyte alpha tocopherol content, erythrocyte glutathione peroxidase activity and serum albumin concentration in twelve patients with uremia not undergoing hemodialysis and fifteen patients on maintenance hemodialysis. RESULTS: The glutathione peroxidase activity in erythrocytes was higher in patients of uremia not undergoing hemodialysis than in chronic hemodialysis patients. A significant negative correlation was observed between the erythrocyte alpha tocopherol content and the degree of erythrocyte membrane lipid peroxidation in chronic hemodialysis patients. There was a statistically significant difference in the degree of erythrocyte membrane lipid peroxidation between patients with chronic hemodialysis-associated hypoalbuminemia and chronic hemodialysis patients having normal serum albumin levels. CONCLUSION: This study suggested that serum albumin inhibits peroxidation of erythrocyte membrane lipids and that hemodialysis induces recovery of serum reductivity. We conclude that persistent hypoalbuminemia worsens the serum antioxidant activity in chronic hemodialysis patients and may contribute to increased oxidative cell damage.

Erythrocyte Membrane↗
PubMed1998

Improvement of promoter activity by the introduction of multiple copies of the conserved region III sequence, involved in the efficient expression of Aspergillus oryzae amylase-encoding genes.

The role of the conserved sequence region III in the promoter regions of the amylase-encoding genes amyB, glaA and agdA of Aspergillus oryzae was examined. Introduction of multiple copies of the region III fragment into the agdA promoter resulted in a significant increase in promoter activity at the transcriptional level. This result suggests that the fragment comprising region III consists of one or more cis-acting sequence(s). Moreover, expression of the agdA gene under the control of the improved agdA promoter resulted in efficient overproduction of alpha-glucosidase, even in the presence of glucose. Thus, overexpression of genes controlled by the improved promoter incorporating region III is possible. Interestingly, expression of the amyB and glaA genes in the transformant was strongly repressed. This result suggests that the trans-acting regulatory protein(s) that interact with region III are common to these amylase genes and that the titration of regulatory protein(s) reduced the expression of the amyB and glaA genes.

Amylases↗
PubMed1998

Identification and characterization of porcine NP-190, a novel protein that is specifically expressed in the axonal membrane during the embryonic period.

To identify and analyze the function of proteins expressed in the growth cones, we have screened monoclonal antibodies raised against the preparation of the growth cone particles derived from fetal porcine brains and found a novel neuronal antigen, termed NP-190. Biochemical characterization of NP-190 demonstrated that it was an integral membrane protein with an apparent molecular weight of 190 kDa and that it was mainly expressed in fetal brains. Homologous antigens with molecular weights of 200 and 170 kDa were also identified in the fetal brain extracts of chickens and rats, respectively. Immunoblot experiments of brain extracts from chickens and rats in various stages of development indicated that the expression of NP-190 homologs was developmentally regulated; it began to appear and increased in the embryonic stage, then decreased to very low level in the adult brains. Immunostaining of cultured primary of neurons from the embryonic day 18 rat cerebral cortex demonstrated that rat NP-190 homolog localized in the cell bodies, axons and growth cones, but not in dendrites. Partial amino acid sequence analysis of affinity-purified NP-190 from fetal porcine brains demonstrated that it was a novel protein. These results suggest that NP-190 plays a distinct role in brain development.

Amino Acid Sequence↗
PubMed1998

Balance of activities of alcohol acetyltransferase and esterase in Saccharomyces cerevisiae is important for production of isoamyl acetate.

Isoamyl acetate is synthesized from isoamyl alcohol and acetyl coenzyme A by alcohol acetyltransferase (AATFase) in Saccharomyces cerevisiae and is hydrolyzed by esterases at the same time. We hypothesized that the balance of both enzyme activities was important for optimum production of isoamyl acetate in sake brewing. To test this hypothesis, we constructed yeast strains with different numbers of copies of the AATFase gene (ATF1) and the isoamyl acetate-hydrolyzing esterase gene (IAH1) and used these strains in small-scale sake brewing. Fermentation profiles as well as components of the resulting sake were largely alike; however, the amount of isoamyl acetate in the sake increased with an increasing ratio of AATFase/Iah1p esterase activity. Therefore, we conclude that the balance of these two enzyme activities is important for isoamyl acetate accumulation in sake mash.

Acetyltransferases↗
PubMed1998

Multidrug resistance phenotype conferred by overexpressing bfr2+/pad1+/sks1+ or pap1+ genes and mediated by bfr1+ gene product, a structural and functional homologue of P-glycoprotein in Schizosaccharomyces pombe.

We investigated the mechanism of multidrug resistance conferred by overexpression of bfr2+/pad1+/sks1+ or pap1+ genes of Schizosaccharomyces pombe. Overexpression of bfr2+ did not confer multidrug resistance on a pap1-disrupted strain. In a mutant with bfr1+ (a putative membrane transporter which belongs to the ATP-binding cassette superfamily) disrupted, overexpression of either bfr2+ or pap1+ did not confer multidrug resistance. These findings suggest that bfr1+ acts as the most downstream effector of the multidrug resistance conferred by bfr2+ and pap1+ genes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

S19159, a modulator of neurite outgrowth produced by the ascomycete Preussia aemulans. I. Producing strain, fermentation, isolation and biological activity.

A modulator of neurite outgrowth, designated S19159, was isolated from the fermentation broth of fungal strain 19159. This fungus was identified as the loculoascomycete, Preussia aemulans (Rehm) von Arx. In the presence of S19159, the number of neurites extending from the cell bodies of cerebral cortical neurons was markedly reduced. The effect of S19159 was observed specifically in neurons from the central nervous system. The compound exhibited similar activities on cultured cortical, hippocampal and cerebeller neurons but was without detectable effect on dorsal root ganglion neurons and PC12 cells.

Animals↗
PubMed1998

[Clinical study on five myeloperoxidase specific anti-neutrophil cytoplasmic antibody (MPO-ANCA) positive Churg-Strauss syndrome cases].

OBJECTIVE: In order to clarify the clinical characteristics of ANCA positive Churg-Strauss syndrome (CSS), ten CSS patients were analyzed. METHODS: ANCA was detected using an immunofluorescence (IF) assay and ELISA. ANCA was measured in both active and inactive stage of the disease. RESULTS: ANCA was present in 5 patients (5/10 : 50%) with active CSS phase and all ANCA patient results showed perinuclear pattern by IF assay and myeloperoxidase specific results by ELISA. Patients with ANCA were older (average age : 58.0) and had higher incidence of renal involvement (4/5 : 80%) than was found with ANCA negative patients (average age; 38.4, no patients with renal involvements). Among 5 patients with ANCA, one had rapidly progressive glomerulonephritis and one had alveolar hemorrhage. Remission was induced for 4 ANCA positive patients by corticosteroid and/or immunosuppressive drug and one required long term maintenance hemodialysis. ANCA titer changed in parallel with disease activity, such as proteinuria, hematuria and alveolar hemorrhage. No significant differences in regard to eosinophilia, serum IgE and CRP titer were found between ANCA positive and negative patients. CONCLUSION: These results strongly indicate that MPO-ANCA may play an important role in the pathogenesis of vascultis, such as renal injury and alveolar hemorrhage in CSS.

Adult↗
PubMed1997

Isolation and characterization of nickel-accumulating yeasts.

We selected three yeast strains that efficiently remove heavy metal ions from aqueous solution. We first screened yeasts that grew in the presence of 2 mM NiCl2 among our stock of wild yeasts, and then selected those that removed Ni most efficiently from aqueous solution. These strains also removed Cu and Zn from aqueous solution and were identified as Candida species. Ni uptake was efficient at pH between 4.0 and 7.0, but less efficient at pH below 3.0. The amount of Ni taken up by the yeast cells was proportional to the initial concentration of NiCl2 below about 4 mM Ni. The cells retained the abilities to remove Ni after treatment with 10 mM EDTA or 1 M HCl for repeated usage, or after heat treatment.

Hydrogen-Ion Concentration↗
PubMed1997

Isolation and characterization of a 230 kDa protein (p230) specifically expressed in fetal brains: its involvement in neurite outgrowth from rat cerebral cortex neurons grown on monolayer of astrocytes.

By screening with monoclonal antibodies (mAbs) raised against growth cone membrane fraction from fetal porcine brains, we have identified a 230 kDa antigen, termed p230. Western blot analysis of extracts from various tissues demonstrated that p230 is specifically expressed in brains, in which its expression is temporally restricted; it was especially prominent in the embryonic and the early postnatal stage, and decreased to subdetectable levels in the adult brain. Further characterization of p230 revealed that it is a peripherally-membrane associated, cell surface protein produced by astrocytes. Neurite outgrowth of E18 rat cerebral cortex neurons cultured on a monolayer of astrocytes was significantly reduced in the presence of anti-p230 polyclonal antibody. Partial amino acid sequences of p230 purified from fetal porcine brains were highly homologous to an extracellular matrix protein, tenascin-C. These lines of evidence suggest that p230, a tenascin-C-like molecule present in fetal porcine brains, plays important roles during early brain development, particularly in growth cone guidance.

Amino Acid Sequence↗
PubMed1997

[MPO-ANCA related vasculitis with pulmonary hemorrhage during propylthiouracil (PTU) therapy].

We described a case of pulmonary hemorrhage associated with myeloperoxidase-antineurophil cytoplasmic antibodies (MPO-ANCA) without renal involvement during propylthiouracil (PTU) treatment. A 36-years old female was admitted to our hospital because of progressive dyspnea with hemosputum after flu-like symptom and episcleritis. She had been receiving PTU for three years to Graves' disease. On admission her chest Xp showed bilateral massive infiltrative shadow and bronchofiberscopy demonstrated pulmonary hemorrhage. MPO-ANCA and anti-thyroperoxidase antibodies were positive, but she had normal urinalysis and normal renal function. After withdraw of PTU, pulmonary hemorrhage disappeared. But 15 days later pulmonary hemorrhage recurred associated with high MPO-ANCA titer. Corticosteroid bolus therapy and oral cyclophasphamide administration improved pulmonary hemorrhage, and MPO-ANCA titer also decreased. It is suggested that MPO-ANCA and PTU might be closely related to the pathogenesis of pulmonary hemorrhage in this case.

Adult↗
PubMed1996

Self-setting, bioactive, and biodegradable TTCP-DCPD apatite cement.

Tetracalcium phosphate-dicalcium phosphate dihydrate self-setting apatite cement mixed with low-crystallized seed hydroxyapatite is similar to the host bone in degree of crystallinity. The bonding strength of this cement with hydroxyapatite-coated titanium rods was twice that with noncoated titanium and four times that with stainless steel. Histologically, TTCP-DCPD apatite cement incorporated into the tibia of rabbits were degraded, absorbed, and replaced by the normal body trabeculae rapidly. The mechanical strength of the cement disk intercalated into a gap made in the rabbit tibiae increased to 73% of that of the normal tibia at 10 weeks concurrently with the decrease in bone mineral density of the disk toward that of the normal tibia, in which bony replacement of the disk was observed also histologically. These bioactive and biodegradative characters of this cement are due to the similarity of its degree of crystallinity to that of the host bone, and could expand its clinical applications.

Animals↗
PubMed1996

A self-setting TTCP-DCPD apatite cement for release of vancomycin.

Vancomycin (VCM), a methiciline-cefem resistant Staphylococcus aureus (MRSA)-specific antibiotic, was incorporated in a self-setting tetracalcium phosphate (TTCP)-dicalcium phosphate dihydrate (DCPD) apatite cement that hardened isothermally into a hydroxyapatite (HAP) phase with crystallinity similar to that of host bone. Effective release of VCM into PBS lasted for 2 weeks from cements containing 1% VCM and for longer than 9 weeks from cements containing 5% VCM. The rate of release of VCM differed between cements with different crystallinities as well as between the two dissolution media, PBS and simulated body fluid. Mean concentration of VCM in the bone marrow tissue released from cements containing 5% VCM was 20 times the minimum inhibitory concentration 3 weeks after implantation in bone. Direct contact with new bone was observed with the cements containing 1% VCM. Slow delivery of VCM from a self-setting TTCP-DCPD apatite cement with low crystallinity could be used to treat MRSA osteomyelitis.

Animals↗
PubMed1996

Deletion analysis of promoter elements of the Aspergillus oryzae agdA gene encoding alpha-glucosidase.

The nucleotide sequence of a 1.5-kb fragment of the promoter region of the Aspergillus oryzae agdA gene encoding alpha-glucosidase was determined. A comparison with the promoter regions of other Aspergillus amylase genes indicated that there are three highly conserved sequences, designated Regions I, II and III, located at -670 nt, -596 nt and -544 nt relative to the start codon, respectively. The function of these consensus sequences in the agdA promoter was investigated by deletion analysis of a promoter fusion with the Escherichia coli uidA gene, using the niaD homologous-transformation system. Deletion of the upstream half of Region III (IIIa; -544 to -529) resulted in a more than 90% reduction in GUS activity and abolished maltose induction, suggesting that Region IIIa is a functionally essential element for high-level expression and maltose induction. Deletion of Region I and the downstream half of Region III (IIIb; -521 to -511) resulted in a significant reduction in GUS activity, but did not affect maltose induction. This suggested that these two elements most likely contain sequences involved in efficient expression in cooperation with Region IIIa. In addition, deletion of a 340-bp region between Region IIIb and the putative TATA box resulted in a 2-fold increase in activity.

Aspergillus oryzae↗