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Y Koizumi

Publications and source records attributed to Y Koizumi.

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

Role of intracellular esterases in the production of esters by Acetobacter pasteurianus.

Esters are the major flavor compounds produced by Acetobacter sp. during vinegar production. The two genes encoding the esterases in the bacteria were disrupted, and the effects of the disruptions studied. When cultured in the presence of ethanol, the est1 gene-disrupted mutant (DE1K) did not produce any ethyl acetate or isoamyl acetate. However, the disruption of est2 did not affect the ester production. Ethyl acetate production by N-23 (pME122P) and DE1K (pME122P), which contain est1, was 1.7-fold higher than that by the wild type, N-23. On analyzing the relationship between ethyl acetate production and the extracellular ethanol and acetic acid concentrations, we found that the highest amount of ethyl acetate was produced when the molar ratio of ethanol and acetic acid was 1:1. These results indicate that the ester production by Acetobacter sp. is mostly catalyzed by the intracellular esterase, esterase-1, with ethanol and acetic acid used as the substrates.

Journal Article↗
PubMed2000

A permease exhibiting a dual role for lysine and biotin uptake in Saccharomyces cerevisiae.

Among Saccharomyces cerevisiae strains each defective in one of 11 amino acid permeases, a lysine permease disruptant (DK) exhibited about 2-fold reductions in maximum cell density and fermentation ability compared to the parent in a synthetic medium. These unusual properties of DK were found to result from the requirement of biotin for growth, in contrast to the parent whose growth was not dependent on external biotin. The rate of 14C-labeled biotin uptake and the intracellular free biotin content of DK were 2-2.5 fold lower than in the parent. We suggest that lysine permease in S. cerevisiae has the ability to transport both lysine and biotin.

Journal Article↗
PubMed2000

Peroxynitrite production by TNF-alpha and IL-1beta: implication for suppression of osteoblastic differentiation.

To determine the roles of nitric oxide (NO) and its metabolite, peroxynitrite (ONOO(-)), on osteoblastic activation, we investigated the effects of a NO donor [ethanamine, 2, 2'-(hydroxynitrosohydrazono)bis- (dNO)], an O(-2) donor (pyrogallol), and an ONOO(-) scavenger (urate) on alkaline phosphatase (ALPase) activity and osteocalcin gene expression, which are indexes of osteoblastic differentiation. dNO elevated ALPase activity in the osteogenic MC3T3-E1 cell line. The combination of dNO and pyrogallol reduced both ALPase activity and osteocalcin gene expression. Because both indexes were recovered by urate, ONOO(-), unlike NO itself, inhibited the osteoblastic differentiation. Furthermore, treatment with a combination of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) was found to yield ONOO(-) as well as NO and O(-2). The reductions in ALPase activity and osteocalcin gene expression were also restored by urate. We conclude that ONOO(-) produced by TNF-alpha and IL-1beta, but not NO per se, would overcome the stimulatory effect of NO on osteoblastic activity and inhibit osteoblastic differentiation.

Alkaline Phosphatase↗
PubMed2000

Effects of lipid composition on the transcorneal penetration of liposomes containing disulfiram, a potential anti-cataract agent, in the rabbit.

We previously demonstrated that topical treatment with disulfiram (DSF) prevented the development of cataracts in sodium selenite-injected rat pups. In biological systems, DSF is rapidly reduced to diethyldithiocarbamate (DDC), a potent antioxidant. In this study, we investigated the effect of altering the lipid composition of liposomes containing DSF on the transcorneal transit of DDC. Liposomes containing DSF were prepared with various molar ratios of dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC) and cetylpyridinum chloride (CPC) by reverse-phase evaporation. Liposomes with a DMPC to DPPC molar ratio of 5:5, examined by differential scanning calorimetry, had the highest enthalpy of transition and the presence of one molar ratio of CPC further enhanced the enthalpy value. The addition of bovine serum albumin or a homogenate of rabbit cornea to the incubation buffer resulted in the release of DDC, but not DSF from the liposomes. The amount of DDC present in the aqueous humor of rabbit eyes following topical administration increased with increase in DMPC to DPPC ratios and was also enhanced by the addition of CPC to the liposomes. The results of this study suggest that liposome formulations are effective for transcorneal drug delivery of anticataract agents such as DSF. DSF in liposomes consisting of DMPC, DPPC, and CPC with a molar ratio of 8:2:1 may be a potential drug formulation for the prevention and/or treatment of cataracts.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1999

Cloning and characterization of ethanol-regulated esterase genes in Acetobacter pasteurianus.

The esterase encoding genes, est1 and est2, were cloned from Acetobacter pasteurianus. Nucleotide sequence analysis of est1 revealed a gene of 954 bp, and est1 coded for an arylesterase with a molecular weight of 34863 Da consisting of 317 amino acids. The est2 gene contained an open reading frame composed of 1221 bp encoding an esterase with a molecular weight of 43389 Da consisting of 406 amino acids. The est1 gene showed some similarity, but the est2 gene showed no significant homology to other esterases reported in various microorganisms. Northern blot analysis of total RNA from A. pasteurianus revealed that transcription of the est1 gene was induced only when the cells were grown in a medium containing ethanol, and suggested that the est1 transcript is monocistronic. In contrast, transcription of the est2 gene was repressed in the presence of ethanol. In the absence of ethanol, expression of the est2-mRNA, capable of encoding a multiple number of proteins, was revealed by Northern blot analysis. In addition, deletion analysis indicated that the 5'-region of the est2 gene contained a cis-acting domain for est2 transcriptional regulation. Analysis of the est1 promoter using the chloramphenicol acetyltransferase gene as a reporter gene showed that the promoter within the 305-bp fragment upstream of the ATG initiation codon was responsible for the transcription in cells grown in the presence of ethanol. Primer extension analysis of est1-mRNA showed that the transcription initiation site was 49 bp upstream from the ATG initiation codon. The results of a gel mobility shift assay indicated that there is a regulatory protein related to est1 regulation, which may have some relation to the ethanol resistance of Acetobacter sp.

Journal Article↗
PubMed1999

Correlation between prevention of cataract development by disulfiram and fates of selenium in selenite-treated rats.

PURPOSE: We found a new pharmacological effect of disulfiram (DSF) against rat pups with cataract induced by selenite injection. The possible reactive mechanism is discussed in this present paper. METHODS: Wistar male and female rats aged 13 and 30 days, and male rats aged 7 weeks were used this present study. Cataract was induced by injection of selenite (19 micromol/kg, s.c.) to 13-day old rats. The lens opacification was monitored by using the slit lamp equipped with an anterior eye segment analysis system (EAS-1000, Nidek). The selenium contents in rat organs were detected fluorimetrically. Liposomes containing DSF (DSF-liposomes) were prepared by the reverse-phase evaporation method. Rat pups were instilled 5 microl of DSF-liposomes into both eyes 4 times per day. Adult rats were administered with DSF suspensions (100 mg/kg) by nasal cannulation. The changes of plasma concentration of diethyldithiocarbamate (DDC), which was a metabolite of disulfiram, were determined by HPLC method. RESULTS: Intraocular treatment with DSF-liposomes prevented the onset of cataract development in rat pups injected with sodium selenite. Treatment with DSF also significantly reduced the selenium contents in plasma at 1 h post-treatment and in the eye at 96 h post-treatment. No significant differences of selenium content in liver and kidney were observed in 13-day old rats instilled with DSF-liposomes or DSF free liposomes. Cataract could not be induced in the 30-days-old rats with the same dose of selenite (19 micromol/kg) and the liver, kidney, and especially eye of the older rats had lower levels of selenium than 13-day old rats. Diethyldithiocarbamate (DDC), an active metabolite of DSF, was decreased in the plasma following a subcutaneous injection of sodium selenite. The selenium concentration in the plasma was decreased by the intranasal administration of DSF suspensions. CONCLUSIONS: Instillation of DSF-liposomes into the eyes of rat pups given a subcutaneous injection of sodium selenite to induce cataracts prevented the formation of cataracts. The mechanism of inhibition may have resulted from a decreased level of selenium in the eyes following the treatment with DSF. On the other hand, as it is known that the cataracts may result from selenite-induced oxidative stress in the lens, DSF and DDC may react as anti-oxidants.

Administration, Intranasal↗
PubMed1999

Identification of the binding region of basic calponin on alpha and beta tubulins.

Calponin is a basic smooth muscle protein capable of binding to actin, calmodulin, tropomyosin, and phospholipids. We have found that the basic calponin interacted with brain tubulin under polymerized and unpolymerized conditions in vitro [Fujii, T., Hiromori, T., Hamamoto, M., and Suzuki, T. (1997) J. Biochem. 122, 344-351]. We examined the calponin-binding site on the tubulin molecule by sedimentation, limited digestion, chemical-cross linking, immunoblotting, and delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometric (DE MALDI-TOF) analyses. Calponin interacts with both the alpha and beta tubulins and only slightly with the tyrosinated and acetylated form of alpha tubulin. The binding of calponin to microtubules was blocked by adding poly(L-aspartic acid) (PLAA) or MAP2. After digestion of microtubule proteins with subtilisin, the amount of calponin binding to alphabetas microtubules was reduced compared to native microtubules, but no further reduction was observed in the case of alphasbetas microtubules. The chemical cross-linked products of calponin and synthesized peptides (KDYEEVGVDSVEGE; alpha-KE) derived from the C-terminal region of alpha tubulin and (YQQYQDATADEQG; beta-YG) and (GEFEEEGEEDEA; beta-GA) from that of beta tubulin were detected by mass spectrometry. One kind of calponin-peptide complex was formed in the presence of alpha-KE or beta-YG, while five complexes (calponin:peptide = 1:1-5) were generated in the presence of beta-GA. Peptides alpha-KE and beta-GA inhibited the binding of calponin to tubulin produced by EDC in a concentration-dependent manner. These findings suggest that basic calponin interacts with both tubulin subunits and that their C-terminal regions, which also contain the binding sites of MAP2, tau, and kinesin, may be involved in calponin-binding.

Amino Acid Sequence↗
PubMed1998

Establishment of a novel cell line (TS-2) of pre-B acute lymphoblastic leukemia with a t(1;19) not involving the E2A gene.

The t(1;19)(q23;p13) translocation involving the E2A gene on chromosome 19p13.3 is a nonrandom translocation that is often seen in childhood pre-B-cell acute lymphoblastic leukemia (ALL). However, recent studies have demonstrated the presence of immunophenotypic and molecular heterogeneity among patients with the cytogenetically identical chromosome translocation. Here we report a novel pre-B ALL cell line, TS-2, with t(1;19) translocation not involving the E2A gene. The breakpoint of t(1;19) in TS-2 was demonstrated to be at 19p13.3, a region indistinguishable from the locus of the E2A gene, by cytogenetic study and fluorescence in situ hybridization. However, rearrangement of the E2A gene was not detected in TS-2 by Southern blot analysis. Moreover, the expressions of PBX1 or E2A/PBX1 fusion genes were not detected by an extensive study with Northern blot analysis and reverse transcription-polymerase chain reaction. These findings suggest that TS-2 may have a genetic abnormality involving uncharacterized gene(s) at 19p13.3 distinct from the E2A gene and, therefore, may be useful for investigating the heterogeneity of molecular pathogenesis in leukemias with t(1;19)(q23;p13) translocation.

Adenovirus E2 Proteins↗
PubMed1998

Improved survival of children with advanced tumors by myeloablative chemotherapy and autologous peripheral blood stem cell transplantation in complete remission.

Five children with neuroblastoma (NB) stage IV and five children with rhabdomyosarcoma (RMS) stage III were treated with myeloablative chemotherapy and autologous peripheral blood stem cell transplantation (MCT/PBSCT) in the state of complete remission (CR) achieved by conventional therapy. PBSCs were collected in CR status using a cell separator with blood access through a double-lumen central venous catheter. PBSCs with 1.9+/-0.8x10(5) of CFU-GM per patient weights (kg) were infused following MCT after a period of conventional therapy for 11.1+/-2.1 or 9.7+/-0.9 months in NB or RMS patients, respectively. Regimen-related toxicity of MCT was tolerable and peripheral white blood cell count recovered beyond 1.0x10(3)/microl 10-12 days after infusion of PBSCs in all patients. All of RMS patients and three of five NB patients survived for an average of 31.6 months (ranged 10.8-58.1). The survival rate of these patients was improved as compared with our historical controls, and presumably, with that of conventional chemotherapy previously reported. Despite a limited number of patients, it appears that MCT/PBSCT may be effective in improving survival by preventing relapse which may occur thereafter if treated with conventional therapy alone. Furthermore, MCT/PBSCT reduced the duration of treatment, as compared with that of conventional chemo-therapy. Therefore, this study may suggest the feasibility and promise of the therapy including MCT/PBSCT for children with advanced stages of NB and RMS.

Antineoplastic Agents↗
PubMed1997

Acute myelogenous leukaemia with t(8;21) translocation of normal cell origin in mosaic Down's syndrome with isochromosome 21q.

We report a 13-year-old girl with Down's syndrome (DS) having a mosaic karyotype of 46,XX/46,XX, -21,+i(21q), who developed acute myelogenous leukaemia (AML) (FAB M1). The t(8;21) translocation generating a AML1/MTG8 chimaeric gene of her blasts was demonstrated by cytogenetic analysis and reverse transcription-polymerase chain reaction. Interestingly, the leukaemic clone with t(8;21) did not have isochromosome 21q, indicating that the blasts were of normal cell origin. These findings suggest that, in older patients with DS, 21 trisomy cells have no greater predisposition to develop AML than normal karyotypic cells.

Adolescent↗
PubMed1997

A case of congenital Listeria septicemia associated with high levels of inflammatory cytokines.

A case of congenital Listeria septicemia is reported. A 2256 g male infant suffering from respiratory and circulatory failure with shock-like symptoms and high levels of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, -6, and -8), was admitted to the Morioka Red Cross Hospital. Listeria monocytogenes was cultured from cord blood, contents from the external ear canal, rectum and stomach. The infant was treated with surfactant replacement as well as conventional therapy. The high levels of interleukin-1 beta decreased with the improvement of the circulatory function, which might have been the major cause of the poor clinical state.

Cytokines↗
PubMed1997

Polyamine content of ordinary foodstuffs and various fermented foods.

Soybeans, tea leaves, and mushrooms were conspicuously rich in spermidine, while oranges contained a large amount of putrescine. Among the fermented foods, soy sauces were rich in putrescine and histamine, while Japanese sake contained plenty of agmatine. These polyamines are thought to be produced from amino acids during fermentation with amino acid decarboxylases formed by the micro-organisms.

Alcoholic Beverages↗
PubMed1997

High efficiency transformation of Bacillus brevis by electroporation.

Various conditions in the Bacillus brevis transformation by electroporation were investigated to increase the efficiency. Competent cell volume and presence of polyethylene glycol 6000 and single stranded DNA on pulsing were critical for the efficiency. As a result, we established the improved method by which 10(7)-10(8) transformants/microgram plasmid DNA could be obtained.

Bacillus↗
PubMed1997

Angiotropic lymphoma diagnosed by muscle biopsy.

On hospitalization, the clinical examination of a 64-year-old female with polyarthralgia and an elevated fever revealed leukocytosis, an increased lactic acid dehydrogenase level, and a positivity for the C-reactive protein. Subsequently, the patient developed muscular pain in the lower limbs. Thus, a muscle biopsy was performed and B-cells with atypia were detected in the arteriolar lumen within the muscle. This led to the diagnosis of angiotropic lymphoma (AL). A combination chemotherapeutic regimen was initiated, and the patient's symptoms disappeared. AL is difficult to diagnose before death, but in this case, muscle biopsy facilitated an early diagnosis and subsequent chemotherapy resulted in the disappearance of the AL. We thus feel this report may be of value.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Changes in DNA copy number in primary gastric carcinomas by comparative genomic hybridization.

We examined 33 primary gastric carcinomas using comparative genomic hybridization to detect changes in the DNA copy number and the chromosomal location of these changes. Ninety-four percent (31 of 33) showed 1 or more DNA copy number changes, such as increases at 2p23-p25 (observed in 21% of the total cases), 3q26.3-q27 (24%), 7p15 (24%), 9p22-pter (18%), and 13q22-q34 (21%) and decreases at 1p34.2-p36.2 (18%) and Y (52%). Histological examination indicated that increases at 3q26.1-q26.3 and 7p15 and decreases at 1p36.1-p36. 2 and Y were commonly observed in both differentiated and undifferentiated types. Increases at 3q27, 6q23-q25, and 7cen-p14 and decreases at 1p34.2-p35 and 17p12 were predominantly observed in the differentiated type, and increases at 2p23-pter, 9p22-pter, and 13q31-qter and a decrease at 6p21.3 were predominantly observed in the undifferentiated type. In addition, clinical staging of tumors showed that increases at 2p23-p25, 7p14-p21, 7q31-q32, and 9p22-pter and a decrease at Y were observed in early-stage tumors, whereas increases at 9q32-q33 and 15q26 were observed only in late-stage tumors. Many of the abnormalities detected in this study were not previously reported in gastric carcinomas. Our comparative genomic hybridization results indicate the presence of genetic alterations that may play some important role in the development and progression of gastric carcinomas.

Adult↗
PubMed1995

Reexamination of properties of prophenoloxidase isolated from larval hemolymph of the silkworm Bombyx mori.

Prophenoloxidase in hemolymph of the silkworm (Bombyx mori) was purified by the method of Ashida (Ashida, M. (1971) Arch. Biochem. Biophys. 144, 749-762) with slight modifications to further increase the purity, and its properties were reinvestigated. The purified prophenoloxidase gave two discrete bands in isoelectric focusing-polyacrylamide gel electrophoresis (IEF-PAGE) (pI 4.95 and 4.98) and in native-polyacrylamide gel electrophoresis with 4.5% separating gel. Each band in IEF-PAGE was separated into two bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with mobilities corresponding to 71.5- and 71-kDa polypeptides. In HPLC on octadecyl column the prophenoloxidase preparation gave two well-separated symmetrical peaks (proPO polypeptide I and proPO polypeptide II). The molecular masses of the proPO polypeptides I and II were determined to be 71.5 and 71 kDa in SDS-PAGE and 78,880 and 81,105 Da by matrix-assisted laser desorption ionization mass spectrometry, respectively. Native prophenoloxidase was eluted at a position corresponding to 126-kDa protein in gel permeation chromatography. Amino acid compositions and peptide mappings of proPO polypeptides indicated that both polypeptides differ in their primary structures. These results are discussed in relation to the subunit structure, the presence of bicopper cluster, and the polymorphism of prophenoloxidase in silkworm hemolymph.

Amino Acids↗
PubMed1995

Aberrant progenitors common to megakaryocytic and myeloid cells in a Down's infant with transient abnormal myelopoiesis.

Phenotypic characteristics of blasts were studied in a Down's infant with transient abnormal myelopoiesis (TAM). Two major subpopulations were identified: (1) CD33+CD42b+ cells with platelet peroxidase activity, the commitment of which to megakaryocytic lineage was supported by an increased expression of GATA-1 mRNA; (2) CD33+CD34+CD7+CD4+ cells with immature ultrastructure, which could be either immature megakaryocytic or myeloid cells with aberrant differentiation. Mixed colonies containing megakaryocytes and monocyte/macrophages in the peripheral blood suggested the presence of progenitors common to these subpopulations. These results may indicate that subpopulations of blasts with phenotypic diversity could be derived from aberrant common progenitors to megakaryocytic and myeloid lineages in this patient.

Blotting, Northern↗