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H Yamagata

Publications and source records attributed to H Yamagata.

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

A comparison of mutation spectra detected by the Escherichia coli lac(+) reversion assay and the Salmonella typhimurium his(+) reversion assay.

Each of the Escherichia coli tester strains in the WP3101P-WP3106P series contains an F' plasmid with a different base substitution mutation within the lacZ gene. Each of the six possible base substitution mutations, therefore, can be assayed with these strains by Lac(+) reversion. We used the strains to characterize the mutational profiles of 21 chemical mutagens, including alkylating agents, base analogs and oxidative compounds. We also assayed the mutagens with Salmonella typhimurium tester strains TA7002, TA7004 and TA7005, which detect A.T-->T.A, G.C-->A.T and G.C-->T.A mutations, respectively, and we compared the sensitivity and specificity of the two systems. Escherichia coli strain WP3102P was more sensitive than the S.TYPHIMURIUM: strains to G.C-->A.T transitions induced by N(4)-aminocytidine, 5-azacytidine, cumene hydroperoxide (CHP), t-butyl hydroperoxide (BHP), N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), methyl methane sulfonate and N-ethyl-N-nitrosourea (ENU), while the reverse was true for G.C-->A.T transitions induced by 2-aminopurine and phosmet. Escherichia coli strain WP3104P, which detects G.C-->T.A transversions, was superior to the S.TYPHIMURIUM: strains in detecting transversions induced by N(4)-aminocytidine, 5-azacytidine, 5-diazouracil, CHP, BHP, ENNG, ENU, 4-nitroquinoline 1-oxide (4-NQO) and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX). Escherichia coli WP3105P was also more sensitive than S. TYPHIMURIUM: to A.T-->T.A transversions induced by N-methyl-N- nitrosourea (MNU), CHP and 4-NQO, but it was less sensitive to those induced by ENNG, ENU and 2-aminopurine. The present results indicate that the E.COLI: Lac(+) reversion system with tester strains WP3101P-WP3106P is as sensitive as the S.TYPHIMURIUM: His(+) reversion system for the detection of specific mutations induced by a variety of direct mutagens.

2-Aminopurine↗
PubMed2000

Molecular cloning and characterization of a cDNA and a gene for subtilisin-like serine proteases from rice (Oryza sativa L.) and Arabidopsis thaliana.

The complete nucleotide sequences of a cDNA (RSP1) that encodes a subtilisin-like serine protease (subtilase) of rice (Oryza sativa L.) and a gene (ASP48) for Arabidopsis subtilase were analyzed. The RSPI cDNA and ASP48 DNA encoded 736- and 757-residue pre-pro-polypeptides including a signal peptide with molecular masses of 78,668 Da and 79,414 Da, respectively. RSP1 is the first known serine protease in rice, and ASP48 is a gene for ara12 cDNA. Sequence comparison and phylogenetic analysis showed that RSP1 is distantly related to all other plant subtilases and ASP48 is closely related to a tomato subtilase, SBT1. The ASP48 gene was found to lack introns. The Arabidopsis subtilase gene appears to consist of a small gene family. The RSP1 was found to be expressed in seed and shoots of seedlings while ASP48 transcripts was found to be accumulated in immature silique and flowers, indicating that both RSP1 and ASP48 are organ-specific and may be involved in the specific proteolytic events that occur during organ development.

Amino Acid Sequence↗
PubMed2000

Efficient production of N-terminally truncated biologically active human interleukin-6 by Bacillus brevis.

cDNAs encoding human interleukin 6 (hIL-6) and its variants lacking the N-terminal Pro and Pro-Val-Pro-Pro, respectively, were expressed in Bacillus brevis by using the signal peptide fusion approach. The presence of Pro at the N-terminus of the mature protein hindered the action of the Bacillus brevis signal peptidase. hIL-6 lacking the N-terminal Pro-Val-Pro-Pro was most efficiently secreted in a biologically active form and accumulated in the culture medium to a level of 200 mg per liter, which is the highest level reported for the bacterial secretion of hIL-6.

Amino Acid Sequence↗
PubMed2000

A modification of Mayer's tannic acid-ferric chloride staining method for demonstrating cellular membranous systems for light microscopy.

To observe cellular membranous systems under a light microscope, we modified Mayer's tannic acid-ferric chloride stain method by adding a treatment with hematoxylin after the original procedure. We used the modified tannic acid-ferric chloride (MTA-Fe) stain method to examine kidneys, liver, heart, trachea, epididymides and other organs of rats and dogs. The MTA-Fe stain clearly demonstrated the basement membrane, brush border, basolateral invaginations and cell processes in the kidneys which enabled easy differentiation of the S1 and S3 segments of proximal convoluted tubules. Our technique also demonstrated hepatic cell membranes and bile canaliculi in the liver, cross striations and longitudinal traveling of myofibrils in the heart, cilia of the epithelial cells in the trachea, and stereocilia and terminal bars in the epididymis. The MTA-Fe stain is a convenient method to visualize cellular membranous systems even for light microscopy. The stain has the advantages of using no toxic materials, simple and easy technique, little variation of staining results, and little fading for several months after staining.

Animals↗
PubMed2000

[A very elderly autopsy case of cecal cancer with pulmonary lymphangitis carcinomatosa].

A 91-year-old man was admitted with colliquative diarrhea, anorexia and weight loss. He had a history of healed tuberculosis, hypertension and atherosclerotic abdominal aortic aneurysms. On admission, shortness of breath without cough, exertional dyspnea, and ascites were also noticed. His chest X-ray and CT showed almost normal findings in the lung fields except for calcified old pleurisy. Since laboratory tests revealed thrombocytopenia, low fibrinogen, and increased CA19-9. DIC induced by an unknown cancer was diagnosed. He died on the eighth day due to progressive respiratory failure which did not respond to oxygen therapy. Autopsy revealed that he had a poorly differentiated adenocarcinoma in the cecum complicated with pulmonary lymphangitis carcinomatosa. Lymphangitis should be considered in the case of unexplained progressive respiratory failure developing in patient with cancer, even in the absence of X-ray findings.

Adenocarcinoma↗
PubMed2000

[A case of amyopathic dermatomyositis with rapidly progressive interstitial pneumonia].

We report here a case of interstitional pneumonia (IP) associated with amyopathic dermatomyositis (DM). In August, 1998, a 53-year-old Japanese man was admitted to our hospital because of fever, polyarthritis and erythematous heliotrope eruption and Gottron's sign without any symptom of myositis. Serum CK level and EMG were normal. Jo-1 antibody was negative. Chest computed tomography (CT) revealed IP at both lung base areas. The patient was diagnosed as amyopathic DM with IP. When IP rapidly progressed, methylprednisolone pulse therapy and oral high dose prednisolone were not effective. High-dose intravenous cyclophosphamide seemed to be transiently effective, but oral cyclosporine A was not effective. The patient was died of respiratory failure in October 1998. During the course, we measured serum levels of LDH, sIL-2 R, s-ICAM-1 and KL-6, KL-6 could be a sensitive parameter of IP activity.

Antigens↗
PubMed1999

Heterogeneity and differential expression under hypoxia of two-domain hemoglobin chains in the water flea, Daphnia magna.

Hemoglobin (Hb) purified from the water flea, Daphnia magna, reared under hypoxia was analyzed by two-dimensional gel electrophoresis. The Hb was shown to be composed of six major subunit chain species (designated as DHbA to DHbF). The NH2-terminal amino acid sequences of DHbA, DHbB, DHbC, and DHbF are different from one another, indicating that at least four Hb genes are present in D. magna. The NH2-terminal amino acid sequences of DHbD and DHbE are the same as those of DHbA and DHbB, respectively. The six Hb chains were also found in the animal reared under normoxia in small amounts and with altered composition; the extent of decrease under normoxia was higher in the amounts of DHbC, DHbD, and DHbF than those of others. These results indicate that the Hb genes are differentially regulated by the ambient oxygen concentration. Four Hb genes constituting a cluster in the order, dhb4, dhb3, dhb1, and dhb2, were found on the chromosome of D. magna. The complete nucleotide sequences of the dhb1, dhb2, and dhb3 genes and their cDNAs showed that the genes have a seven-exon, six-intron structure. The structure consists of an intron separating an exon encoding a secretory signal sequence, two large repeated regions of a three-exon, two-intron structure that encode each a domain containing a heme-binding site, and an intron bridging the two repeated regions. The deduced amino acid sequences of the gene products showed higher than 79% identity to one another and showed unique features conserved in D. magna Hb chains. The analysis also suggested that DHbB (or DHbE), DHbF, and DHbC are encoded by the dhb1, dhb2, and dhb3 genes, respectively.

Amino Acid Sequence↗
PubMed1999

Mutation spectra of chemical mutagens determined by Lac+ reversion assay with Escherichia coli WP3101P-WP3106P tester strains.

We previously reported the development of mutation-specific Escherichia coli B tester strains WP3101 to WP3106 from strain WP2uvrA. In this study we constructed their pKM101-containing derivatives WP3101P to WP3106P, and further isolated their rfa derivatives WP4101-WP4106 and WP4101P-WP4106P. The six kinds of F' plasmids (lacI-, lacZ-, proAB+), each of which carries a different lacZ allele, contained in the above strains were originally derived from E. coli K-12 strains CC101-CC106. All the tester strains show Lac- and Trp- phenotype. Assays for transitions and transversions are based upon Lac+ reversion of a specific mutation located within the lacZ gene on an F' plasmid. The trpE65(ochre) allele in the same strains enables them to be used for Trp+ reversion assays as well. In the present paper, we evaluated the sensitivity, specificity, and usefulness of the newly developed tester strains. Strains WP3101P-WP3106P were highly sensitive to determine mutational profile of heterocyclic amines with S9 mix-mediated metabolic activation and most of the oxidative mutagens and free radical generators tested. Every type of base-pair substitutions induced by 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) or 5-diazouracil were detected in strains WP3101P-WP3106P, while A:T-->C:G and G:C-->A:T mutations induced by MeIQ, and A:T-->C:G, G:C-->A:T, and G:C-->C:G by 5-diazouracil were not detected in pKM101-free tester strains. In pKM101-carrying strains, cumene hydroperoxide induced all types of base substitutions, while formaldehyde preferentially induced G:C-->T:A transversions. Phenazine methosulfate induced predominantly G:C-->A:T transitions and G:C-->T:A transversions, while H2O2 induced predominantly G:C-->T:A and A:T-->T:A transversions. Introduction of the rfa mutation considerably enhanced sensitivity to bulky mutagens such as polycyclic aromatic compounds. All six possible base substitutions induced by 9, 10-dimethyl-1,2-benzanthracene (DMBA) were detected in tester strains WP4101P-WP4106P. In conclusion, our tester strains WP3101P-WP3106P and WP4101P-WP4106P permitted rapid and simple detection of specific mutations induced by variety of mutagens.

Animals↗
PubMed1999

Identification of mutable slender glume gene in rice (Oryza sativa L.).

The segregation pattern and chromosomal location of a slender glume mutation, induced by gamma-ray irradiation, was investigated. The mutation is genetically unstable: in the selfed progenies of slender glumed plants, not only plants with normal glumes but also plants that are chimeric for glume shape almost always appear at low frequency. The results showed that the mutation is controlled by a single recessive, mutable mutant gene slg. The frequency of reversion of slg to its wild-type state was little affected by crossing, back-crossing, genetic background or cytoplasmic factors. Conventional trisomic and linkage analyses revealed that the slg locus was located close to the rfs (rolled fine stripe leaf) locus on chromosome 7. In a subsequent RFLP analysis, slg was found to be located between the two RFLP loci XNpb20 and XNpb33, with recombination values of 3.0 and 3.2%, respectively. Southern analysis indicated that the mutability of slg is caused by none of the known transposable elements in rice. From these results, we infer that slg has a novel transposable DNA insert in its vicinity, which was possibly activated by gamma-ray irradiation.

Chimera↗
PubMed1999

Polymorphism of heat-shock protein gene HSP70-2 in Crohn disease: possible genetic marker for two forms of Crohn disease.

BACKGROUND: Previous reports have shown that heat-shock protein 70 (HSP70) may be associated with Crohn disease. However, genetic analysis of the HSP70 gene in Crohn disease has not been done. The aim of this study is to investigate whether HSP70-2 gene polymorphism is involved in susceptibility to Crohn disease in the Japanese population and whether it correlates with clinical manifestation of the disease. METHODS: A total of 108 genetically unrelated patients with Crohn disease and 108 healthy controls were typed for HSP70-2 PstI polymorphism by restriction fragment length polymorphism analysis (alleles A and B). Patients with Crohn disease were classified into two types: either perforating or non-perforating. RESULTS: Genotype and allele frequency did not differ between patients and controls. In patients with Crohn disease, allele A frequency was significantly higher in the non-perforating than in the perforating type (P = 0.02). When patients with Crohn disease of more than 6.7 years' duration were assessed, the differences in genotype and allele frequency between the two groups became more significant (P < 0.001 and P < 0.001, respectively). CONCLUSIONS: These data suggest that HSP70-2 gene polymorphic allele A is a possible genetic marker of less severe clinical phenotype in Japanese patients with Crohn disease.

Adolescent↗
PubMed1999

[Genomic instability and neurodegenerative disease].

The discovery of unstable DNA sequences as the cause of genetic disease is a fascinating new area in human genetics, raising a number of important questions addressing the understanding of both the mechanisms and the effects of this new type of mutation. Trinucleotide repeat expansion mutations have been identified in a number of neurodegenerative diseases, including spinal and bulbar muscular atrophy (SBMA), fragile X syndrome (FRAXA and FRAXE), myotonic dystrophy (DM), Huntington's disease (HD), spinocerebellar ataxia types 1, 2, 3, 6, 7 (SCA1, SCA2, SCA3, SCA6, SCA7), dentatorubral-pallidoluysian atrophy (DRPLA), Friedreich's ataxia (FRDA) and autosomal dominant pure spastic paraplegia (ADPSP). They have been traced to genetic variation in the length of (CTG)n/(CAG)n, (CGG)n/(CCG)n, or (GAA)n/(TTC)n triplet repeats in DNA. In normal individuals these loci contain a short length of triplet repeats (usually 5-40), which is polymorphic within the population. Increases in the lengths of the translated triplet repeats to 40-100 are associated with disease symptoms, whereas the untranslated triplet repeats to 200-3000 are associated with the disease. We concentrated on repeat expansions in myotonic dystrophy. In this symposium, we outline the molecular aspects of myotonic dystrophy including DNA diagnosis and anticipation, and review the similarities and differences among these triplet repeat diseases.

Humans↗
PubMed1998

Development of new tester strains derived from E. coli WP2uvrA for the determination of mutational specificity.

We have developed a set of multipurpose tester strains (WP3101 to WP3106) derived from E. coli WP2uvrA for the detection and classification of mutagens. Six kinds of F' plasmid (lacI, lacZ, proAB+) in strains CC101-CC106, each of which carried a different lacZ allele, were transferred to a delta(lac-pro) derivative of WP2uvrA. Assays for transitions and transversions are based upon Lac+ reversion of a specific mutation located within the lacZ gene on an F' plasmid in strains WP3101-WP3106. In addition, the trpE65(ochre) allele in the same strains is available for Trp+ reversion assays. Using the new tester strains, we investigated the mutational specificities of various chemical mutagens. Base analog mutagens and alkylating mutagens induced specific types of base substitutions. G:C-->A:T transitions and G:C-->T:A transversions predominated in mutagenesis induced by 4-nitroquinoline 1-oxide. Only a slight increase in G:C-->T:A transversions was observed in cells treated with 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2), although the potent mutagenicity of AF-2 was detected in a concurrent Trp+ reversion assay in the same strain. Sodium azide, on the other hand, was negative in the Trp+ reversion assay but specifically induced G:C-->A:T transitions. Present finding suggested that target sites for AF-2- and azide-induced lesions may largely depend on sequence context.

4-Nitroquinoline-1-oxide↗
PubMed1998

An assay system for detecting environmental toxicants with cultured cladoceran eggs in vitro: malformations induced by ethylenethiourea.

An in vitro assay system using cladoceran eggs was developed for the detection of toxic compounds in the aquatic environment. Parthenogenetic eggs of Daphnia magna were removed from the brood chambers of female adults and cultured individually in 96-well microtiter plates with Elendt M7 medium at 23 degrees C. Embryonic development proceeded completely in vitro with more than 95% hatchability. Egg development time in vitro was 2 days, which was almost equal to that in the brood chamber of the mother. Ethylenethiourea, a compound teratogenic to mammals, was investigated for toxicity to development of eggs. Isolated eggs were cultured in the presence of ethylenethiourea during the period of embryonic development for 3 days. Treatment with ethylenethiourea induced morphological abnormalities in the cladoceran carapace. Parthenogenetic eggs of Cladocera are genotypically identical, which makes them useful biological materials for a toxicity test on aquatic pollutants.

Animals↗
PubMed1998

Further evidence for a major ancient mutation underlying myotonic dystrophy from linkage disequilibrium studies in the Japanese population.

The myotonic dystrophy (DM) mutation is an unstable (CTG)n repeat, present at a copy number of 5-37 repeats on normal chromosomes but amplified to 50-3000 copies on DM chromosomes. Previous findings in Caucasian populations of a DM founder chromosome raise a question about the molecular events involved in the expansion mutation. To investigate whether a founder chromosome for the DM mutation exists in the Japanese population, we genotyped families using polymorphic markers near the (CTG)n repeat region and constructed haplotypes. Six different haplotypes were found and DM alleles were always haplotype A. To find an origin of the (CTG)n repeat mutation and to investigate the mechanism of the expansion mutation in the Japanese population we have studied 90 Japanese DM families comprising 190 affected and 130 unaffected members. The results suggest that a few common ancestral mutations in both Caucasian and Japanese populations have originated by expansion of an ancestral n = 5 repeat to n = 19-37 copies. These data support multistep models of triplet repeat expansion that have been proposed for both DM and Friedreich's ataxia.

Adult↗
PubMed1998

Molecular analysis of two pre-mutations in myotonic dystrophy.

Here we report two families with myotonic dystrophy (DM) in which the asymptomatic parent proved to be in a pre-mutation state. Polymerase chain reaction (PCR) analysis of the region spanning the CTG expansion demonstrated that one father of the proband possessed (CTG)n repeats of n = 12 and 44 copies and the other of 15 and 47. Clinical examination showed no definite signs of DM in these two men. Haplotype analysis of DNA markers close to the DM protein kinase (DMPK) gene suggested a common ancestral DM mutation. A continuous gradient of repeat sizes from normal to abnormal range can explain this phenomenon.

Adult↗
PubMed1998

Cloning and expression of the soybean chlH gene encoding a subunit of Mg-chelatase and localization of the Mg2+ concentration-dependent ChlH protein within the chloroplast.

From the soybean cDNA library, we isolated and analyzed the chlH gene encoding a subunit of Mg-chelatase. The subunit was a polypeptide of 1,383 amino acids with a molecular mass of 153,491 Da, which shared 90% identity with the olive gene from Antirrhinum majus. The regulation of the expression of chlH was investigated in photomix-otrophic soybean suspension cells (SB-P). The expression was light-inducible, and the induction was more rapid than those of chlI and cab2. Furthermore, the levels of the transcripts and products of chlH appeared to be regulated by a circadian oscillation. The subchloroplastic localization of ChlH was investigated by immunoblot analyses with antiserum against recombinant ChlH. Depending on the concentration of Mg2+ in the lysis buffer, the localization of ChlH protein migrated between the stroma and the envelope membrane; ChlH was localized on the envelope membrane, a major site of chlorophyll biosynthesis, when the Mg2+ concentration of the lysis buffer was high (above 5 mM). These results indicated that the activity of Mg-chelatase was regulated by modulation of the expression and subchloroplastic localization of ChlH protein.

Amino Acid Sequence↗