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H Yamagata

Publications and source records attributed to H Yamagata.

At least 73 records · Page 4Linked to original sources
PubMed1995

Cloning, subcellular localization and expression of CHL1, a subunit of magnesium-chelatase in soybean.

Mg-insertion is the first committed step in chlorophyll synthesis and is catalyzed by Mg-chelatase. In photosynthetic bacteria, bchI gene product was suggested to be a subunit of Mg-chelatase. We isolated a bchI homolog from a soybean cDNA library and designated it as chlI. CHLI consisted of 421 amino acid residues and the sequence exhibited a high similarity to other BchI homologs. CHLI contained an ATP-binding motif found in other BchI homologs. CHLI was localized in the soluble fraction in soybean chloroplasts, suggesting that it was a stromal subunit of Mg-chelatase. chlI mRNA in cell culture (SB-P) of soybean was reversibly induced by light.

Adenosine Triphosphate↗
PubMed1995

Epidemiological and clinical features of Budd-Chiari syndrome in Japan.

The Japanese Ministry of Health and Welfare Research Committee on Aberrant Portal Blood Flow carried out an epidemiological survey and clinical study on Budd-Chiari syndrome in 1990. In the primary survey for determining the prevalence of the disease, a questionnaire was sent to all major hospitals throughout Japan and 160 cases seen in 1989 were compiled. More epidemiological details were obtained in 87 of these 160 cases. The number of patients with Budd-Chiari syndrome in this country was estimated to be about 300 (prevalence of 2.4/million) with about 20 new cases occurring every year. In the clinical study, 157 authentic cases of Budd-Chiari syndrome studied in 15 years (1975-89) were analyzed. There were 87 males (average age, 36.4 years) and 70 females (46.5 years), and the average period from the likely onset to the first medical consultation was 6.6 years, suggesting that these patients were mostly chronic cases. The main clinical features were hepatomegaly, leg edema, ascites and venous dilatation over the trunk. Abdominal pain was recorded in only four (2.5%). There were 16 (10.2%) with known identifiable etiologies. Of the patients 93% showed an obstructing lesion of various thickness in the hepatic portion of the inferior vena cava. Only nine (5.7%) had hepatic vein obstruction without caval lesions. Thus, the majority of Budd-Chiari syndrome patients in Japan are idiopathic, having an obstructing lesion in the inferior vena cava. The main causes of 33 deaths (21%) were liver failure, variceal bleeding and hepatocellular carcinoma. Hepatocellular carcinoma occurred in 10 (6.4%) in the 15-year period. However, the incidence of Budd-Chiari syndrome among all cases of hepatocellular carcinoma was less than 1% in the survey made by the Liver Cancer Study Group of Japan.

Adult↗
PubMed1995

Congenital myotonic dystrophy: molecular diagnosis and clinical study.

Recently, an unstable DNA fragment specific to myotonic dystrophy (MyD) was discovered. In affected individuals, a DNA fragment is found that is larger than in normal siblings. Our objectives were to show whether the results of DNA analysis agree with the disease severity and prognosis in congenital myotonic dystrophy (CMyD) by DNA analysis. We investigated three pregnancies (two studied retrospectively) in three families. We genotyped the family members with the Southern blots and the polymerase chain reaction (PCR) analysis. In one case a prenatal diagnosis was carried out using chorionic villus sampling. This report also presents the three cases of affected mothers and CMyD babies with their growth courses. We clarify four main problems in CMyD, namely, respiratory distress, delayed motor development, feeding difficulty, and delayed mental development. The allele size in the range of 10 to 13 kb tended to be present as the adult form of MyD, and 14 to 15 kb as the CMyD. The three CMyD cases whose alleles size in the range of 14 to 15 kb showed various forms of disease and prognosis. We reached the following conclusions: the disease severity and prognosis in babies with CMyD did not correlate with the result of DNA analysis. The DNA analysis is a useful test for prenatal diagnosis. However, it is impossible to predict the disease severity and prognosis in babies with CMyD.

Adult↗
PubMed1995

Cloning and characterization of the gene for a protein thiol-disulfide oxidoreductase in Bacillus brevis.

The gene (bdb) for protein thiol-disulfide oxidoreductase cloned from Bacillus brevis was found to encode a polypeptide consisting of 117 amino acid residues with a signal peptide of 27 residues. Bdb contains a well-conserved motif, Cys-X-X-Cys, which functions as the active center of disulfide oxidoreductases such as DsbA, protein disulfide isomerase, and thioredoxin. The deduced amino acid sequence showed significant homology with those of several bacterial thioredoxins. The bdb gene complemented the Escherichia coli dsbA mutation, restoring motility by means of flagellar and alkaline phosphatase activity. The Bdb protein overproduced in B. brevis was enzymatically active in both reduction and oxidization of disulfide bonds in vitro. Immunoblotting indicated that Bdb could function at the periphery of the cell.

Amino Acid Sequence↗
PubMed1995

Development of anti-Sm and anti-DNA antibodies followed by clinical manifestation of systemic lupus erythematosus in an elderly woman with long-standing Sjögren's syndrome.

A 69-year-old Japanese women who had been followed up for 10 years as a primary Sjögren's syndrome, is reported. She suddenly developed serological and clinical characteristics of systemic lupus erythematosus (SLE): anti-Sm and anti-dsDNA antibodies followed by nephrotic syndrome and pancytopenia. This case suggests that the diagnosis of primary Sjögren's syndrome should be considered as tentative in certain cases and that the development of serological characteristics precede and are associated with the development of clinical symptoms of SLE.

Aged↗
PubMed1995

BbrPI, an extracellular proteinase inhibitor of Bacillus brevis, protects cells from the attack of exogenous proteinase.

BbrPI, an extracellular serine proteinase inhibitors of B. brevis HPD31, is activated by proteolytic processing of an inactive precursor. To discover the physiological role of BbrPI, its deficient mutants were genetically constructed. Although the BbrPI deficient mutant had a higher extracellular proteinase activity than the parent strain, it grew normally. The BbrPI deficient mutant showed higher sensitivity to added trypsin than that of the parent. These observations suggest that the BbrPI may play a role in cellular protection from the attack of exogenous proteinases.

Bacillus↗
PubMed1995

[Molecular genetics of myotonic dystrophy].

The gene for myotonic dystrophy (DM) was found to be an expansion of an unstable CTG repeat located in the 3'-UTR of the putative protein kinase gene. In the general population 5 approximately 37 copies of the repeat are present, but in DM patients the repeat number varies from 50 up to thousands of copies. We have determined the copy number of the CTG repeat and made a haplotype using the closely linked markers to the CTG repeat in 93 Japanese DM families. The absolute linkage disequilibrium was observed in patients from both populations, between the DM gene and the linked markers. These data strongly suggest a common origin of Caucasian and Japanese DM alleles. The genetic analysis of apparently sporadic occurrence of DM in a family in which two asymptomatic members have been shown to have a number of repeats corresponding to premutation alleles, 44 and 46 CTG alleles. These data strongly suggest that (CTG) 19 approximately 37 may act as a predisposing allele for successive DM generations and that there is a premutation allele for DM, as predicted in a multistep model for etiology of this disorder.

Alleles↗
PubMed1994

Cucumisin, a serine protease from melon fruits, shares structural homology with subtilisin and is generated from a large precursor.

Cucumisin is a thermostable alkaline serine protease that is found in the juice of melon fruits (Cucumis melo L.). We have determined the complete nucleotide sequence of a cucumisin cDNA (2,552 nucleotides) and deduced the corresponding amino acid sequence. The open reading frame of the cDNA consists of 731 codons and encodes a large precursor (molecular weight, 78,815) relative to the observed size of mature native cucumisin (67 kDa). Sequence comparisons reveal that cucumisin has several features in common with the microbial proteases of the subtilisin family. The highly conserved sequences to the proximal regions of the catalytic triad amino acids Asp, His, and Ser, together with the substrate binding site in subtilisin, can be found within the deduced amino acid sequence of the protease domain of the cucumisin precursor. Cucumisin is the first known plant protease with such characteristics. Examination of the primary structure of cucumisin revealed that it is synthesized as a precursor, consisting of four functional domains: a possible signal peptide (22 amino acid residues), an NH2-terminal pro-sequence (88 residues), a 54-kDa protease domain (505 residues), which is the active enzyme domain of the 67-kDa native cucumisin, and a 14-kDa COOH-terminal polypeptide (116 residues), which arises by limited autolysis of the 67-kDa native cucumisin. This structure of cucumisin suggests that it is probably synthesized as an inactive precursor.

Amino Acid Sequence↗
PubMed1994

Phytochrome signal transduction pathways are regulated by reciprocal control mechanisms.

Three signal transduction pathways, dependent on cGMP and/or calcium, are utilized by phytochrome to control the expression of genes required for chloroplast development and anthocyanin biosynthesis in plant cells. For example, chs is controlled by a cGMP-dependent pathway, cab is controlled by a calcium-dependent pathway, and fnr is regulated by a pathway that requires both cGMP and calcium. Using a soybean photomixotrophic cell culture and microinjection into the cells of a phytochrome-deficient tomato mutant, we have studied the regulatory mechanisms acting within and between these three signaling pathways. We provide evidence that changes in cGMP levels mediate the observed induction and desensitization of chs gene expression in response to light and demonstrate that high cGMP concentrations cause negative regulation of both the calcium- and the calcium/cGMP-dependent pathways. Conversely, high activity of the calcium-dependent pathway can negatively regulate the cGMP-dependent pathway. We have termed these opposing regulatory mechanisms reciprocal control. In all cases, the molecules that are involved appear to be downstream components of the signal transduction pathways, rather than calcium and cGMP themselves. Furthermore, we have found that the calcium/cGMP-dependent pathway has a lower requirement for cGMP than does the cGMP-dependent pathway. The role of these phenomena in the regulation of plant photoresponses is discussed.

Calcium↗
PubMed1994

Cyclic GMP and calcium mediate phytochrome phototransduction.

We have previously used single-cell assays in a phytochrome-deficient tomato mutant to demonstrate that phytochrome signaling involves heterotrimeric G proteins, calcium, and calmodulin. While G protein activation could stimulate full chloroplast development and anthocyanin pigment biosynthesis, calcium and calmodulin could not induce anthocyanins and were only able to stimulate the development of immature chloroplasts lacking cytochrome b6f and photosystem I core components. We now report that cyclic GMP is able to trigger the production of anthocyanins, and that a combination of cyclic GMP with calcium can induce the development of fully mature chloroplasts containing all the photosynthetic machinery. Furthermore, using reporter genes for these different pathways (cab-gus, chs-gus, and fnr-gus) we demonstrate that cGMP and calcium act primarily by modulating gene expression.

Anthocyanins↗
PubMed1994

Direct high-level secretion into the culture medium of tuna growth hormone in biologically active form by Bacillus brevis.

The characteristic features of the Bacillus brevis system developed by us are very high productivity of heterologous proteins and very low extracellular proteinase activity. However, the production level of eucaryotic proteins with this system was generally one or two orders of magnitude lower than that of bacterial proteins. Therefore, we have explored methods for increasing the production efficiency as to animal proteins. Signal peptide modification was found to be very effective for high-level secretion of tuna growth hormone (tGH). Modification of the signal peptide with higher basicity in the amino terminal region and higher hydrophobicity in the middle region brought about a ten-fold increase in tGH production. Further elevation of the tGH yield to 240 mg/l was achieved by using a low proteinase mutant and a stable plasmid, and by culturing B. brevis under optimal conditions with the addition of some chemicals. Thus, biologically active tGH can be efficiently produced directly in the medium with this B. brevis system.

Amino Acid Sequence↗
PubMed1994

Characteristics of dynamic mutation in Japanese myotonic dystrophy.

To study the characteristics, if any, of unstable CTG repeat sequence in Japanese myotonic dystrophy (DM), we analyzed DNA from 351 at risk individuals (including affected and non-affected carriers and their descendants) from 105 families in Japan. A total of 93 DM families (196 affected and 116 unaffected individuals), including 84 DM parent-child pairs (44 father-child and 40 mother-child pairs), were examined, many of which had been previously tested by linkage analysis. We detected unstable CTG repeat mutations between 0.15 kb and 8.7 kb in size. The size of the mutation correlated with the age of onset of symptoms. There was a significant difference in DM allele size among the four groups (congenital, juvenile onset, classical, and minimal). Congenital DM had on average the largest repeat sizes. Comparison of parent-child pairs showed that most offspring had a larger repeat size than their parents, with only 2 of 84 showing a definite decrease in repeat size. The correlation coefficients for maternal and paternal transmission were 0.41 and 0.15, respectively. The parental age (maternal and paternal) did not correlate with intergenerational change of repeat. These observations are similar to those reported in Caucasians.

Adolescent↗
PubMed1994

Recurrent annular erythema with anti-SSA/Ro and anti-SSB/La antibodies localized on palms and fingers in an elderly man.

A 69-year-old Japanese man with recurrent annular erythema localized on palms and flexor surface of fingers with anti-SSA/Ro and anti-SSB/La antibodies, is reported. The present case indicates that even in an elderly man with atypical localization, annular erythema with autoimmunity may be considered and serological analysis should be performed. Systematic studies will be required to understand the relationship between 'recurrent annular erythema associated with anti-SSB/La antibodies' in Japanese, subacute cutaneous lupus erythematosus (SCLE) and 'annular erythema associated with Sjogren's syndrome'.

Aged↗