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H Sekimoto

Publications and source records attributed to H Sekimoto.

At least 19 recordsLinked to original sources
PubMed1999

Regulation of gibberellin biosynthesis genes during flower and early fruit development of tomato.

Gibberellins (GAs) are essential for the development of fertile flowers in tomato, and may also be required immediately after fertilization. In the GA-biosynthetic pathway, the reactions catalyzed by GA 20-oxidases have been implicated as site of regulation. To study the regulation of GA biosynthesis in flower and early fruit development, we isolated three tomato GA 20-oxidase cDNA clones, Le20ox-1, -2 and -3. The three genes showed different organ-specific patterns of mRNA accumulation. Analysis of the transcript levels of the three GA 20-oxidase genes, as well as those of copalyl diphosphate synthase (LeCPS) and GA 3 beta-hydroxylase (Le3OH-2) during flower bud and early fruit development, revealed temporally distinct patterns of mRNA accumulation. Up until anthesis, transcripts were observed for LeCPS, Le20ox-1, -2 and Le3OH-2, with an accumulation of Le20ox-1 mRNA. In contrast to the high level of Le3OH-2 transcripts in the fully open flower, mRNA levels of Le20ox-1, -2 and LeCPS were reduced at this stage. After anthesis, LeCPS and Le20ox-1 transcripts increased again. In addition, Le20ox-3transcripts increased whereas the transcripts of Le3OH-2 decreased to an undetectable level. In situ hybridization results demonstrated that during early stages of bud development, Le20ox-2 transcripts were localized in the tapetum and placenta. The presented results supply novel data about localization of GA biosynthesis gene transcripts, and indicate that transcript levels of GA biosynthesis genes are all highly regulated during flower bud development.

Alkyl and Aryl Transferases↗
PubMed1998

Molecular cloning of a novel sex pheromone responsible for the release of a different sex pheromone in Closterium peracerosum-strigosum-littorale complex.

A sex pheromone, protoplast-release-inducing protein (PR-IP) inducer, of the Closterium peracerosum-strigosum-littorale complex is known to induce the release of PR-IP, from mating-type plus (mt+) cells during sexual reproduction. The purified PR-IP inducer was treated with trypsin to obtain internal peptides for determination of partial amino acid sequences. Using these sequences, oligonucleotides were synthesized and used as primers for the combined reverse transcription-PCR. A 296 bp cDNA fragment was amplified, permitting the cloning of corresponding full length cDNA (CpPI; Closterium peracerosum-strigosum-littorale complex PR-IP inducer). The deduced amino acid sequence of CpPI encodes a protein of 212 amino acid residues of M(r) 23,071 whereas portion of the peptide secreted is predicted to have 142 amino acid residues of M(r) 15,717 and shows no significant similarity with known proteins. The predicted protein has three possible consensus sequences for asparagine-linked glycosylation site. The CpPI gene was expressed when mating-type minus (mt-) cells were incubated at a low cell density in the light. Nitrogen deprivation from the medium enhances expression of the CpPI gene. An analysis by genomic Southern hybridization revealed that the cDNA probe hybridized to several DNA fragments obtained from both the genome of mt- and mt+ cells. However, in mt- cells, transcripts for the PR-IP inducer could not be detected by Northern hybridization.

Amino Acid Sequence↗
PubMed1998

Molecular cloning and characterization of aldehyde oxidases in Arabidopsis thaliana.

Using degenerate primers designed by deduced amino acid sequences of known aldehyde oxidases (AO) from maize and bovine, two independent cDNA fragments were amplified by reverse transcription-polymerase chain reaction (PCR). The two corresponding full-length cDNAs (atAO-1 and atAO-2; 4,484 and 4,228 bp long, respectively) were cloned by screening the Arabidopsis cDNA library followed by rapid amplification of cDNA end-PCR. These cDNAs are highly homologous at both the nucleotide and amino acid sequence levels, and the deduced amino acid sequences showed high similarity with those of maize and tomato AOs. They contain consensus sequences for two iron-sulfur centers and a molybdenum cofactor (MoCo)-binding domain. In addition, another cDNA having a sequence similar to that of the cDNAs was screened (atAO-3; 3,049 bp), and a putative AO gene (AC002376) was reported on chromosome 1, which (atAO-4) was distinct from, but very similar to, the above three AOs. atAO-1, 2, 3, and 4 were physically mapped on chromosomes 5, 3, 2 and 1, respectively. These data indicate that there is an AO multigene family in Arabidopsis. atAO-1 protein was shown to be highly similar to one of the maize AOs in respect to a region thought to be involved in determination of substrate specificity, suggesting that they might encode a similar type of AO, which could efficiently oxidize indole-3-acetaldehyde to indole-3-acetic acid (IAA). atAO-1 and atAO-2 genes were expressed at higher levels in lower hypocotyls and roots of the wild-type seedlings, while atAO-3 was slightly higher in cotyledons and upper hypocotyls. The expression of atAO-1 was more abundant in the seedlings of an IAA overproducing mutant (superroot1; sur1) than in those of wild type. atAO-2 and atAO-3 transcripts were rather evenly distributed in these seedlings. A possible involvement of atAO genes in phytohormone biosynthesis in Arabidopsis is discussed.

Aldehyde Oxidoreductases↗
PubMed1997

Cloning and molecular characterization of plant aldehyde oxidase.

Primary structural information of a plant aldehyde oxidase (AO), which was purified from maize coleoptiles using indole-3-acetaldehyde as a substrate, was obtained by sequencing a series of cleavage peptides, permitting the cloning of the corresponding cDNA (zmAO-1). The complete nucleotide sequence was determined; the deduced amino acid sequence encodes a protein of 1358 amino acid residues of Mr 146,681, which is consistent with the size of the AO monomeric subunit. There is a significant similarity with AO from mammals and xanthine dehydrogenases from various sources. The maize AO polypeptide contains consensus sequences for iron-sulfur centers and a putative molybdopterin cofactor-binding domain. In addition, another cDNA (zmAO-2), highly homologous to zmAO-1 at both the nucleotide and amino acid sequence levels, was cloned. zmAO-2 would encode a protein of 1349 amino acid residues of Mr 145,173 and has molecular characteristics similar to those of zmAO-1. zmAO-1 was expressed at a high level in roots, which was closely correlated with immunoblotting results using antiserum raised against the purified maize AO protein, whereas zmAO-2 was expressed at a higher level in coleoptiles than in roots. We propose each zmAO may have a unique function during plant development.

Aldehyde Oxidase↗
PubMed1997

Simplified method for the determination of 25-hydroxy and 1alpha,25-dihydroxy metabolites of vitamins D2 and D3 in human plasma. Application to nutritional studies.

A simplified method for the determination of 25-hydroxy and 1alpha,25-dihydroxy metabolites of vitamins D2 and D3 in human plasma was developed. Plasma samples were deproteinizated and applied to a Bond Elut C18OH cartridge to separate 25-hydroxyvitamin D (25-OH-D) and 1alpha,25-dihydroxyvitamin D [1,25(OH)2D] fractions. The 25-OH-D fraction was purified by a Bond Elut C18 cartridge and 25-OH-D2 and 25-OH-D3 were assayed by HPLC using a Zorbax SIL column. The 1,25(OH)2D fraction obtained above was subsequently applied to HPLC using a Zorbax SIL column to separate 1,25(OH)2D2 and 1,25(OH)2D3 fractions which were determined by a radioreceptor assay (RRA) using calf thymus receptor. The method was applied to nutritional studies.

25-Hydroxyvitamin D 2↗
PubMed1997

Cloning of a cDNA for a 1-aminocyclopropane-1-carboxylate synthase that is expressed during development of female flowers at the apices of Cucumis sativus L.

In cucumber (Cucumis sativus L.) plants, it has been reported that a high correlation existed between the evolution of ethylene from the apices and the development of female flowers. We isolated three distinct cDNA encoding 1-aminocyclopropane-1-carboxylate (ACC) synthase from cucumber. Among of these, only CS-ACS2 mRNA was detected at the apices of gynoecious cucumber in which female flowers were developing. The expression of the CS-ACS2 gene was examined in the apices of three cucumber cultivars (Rensei, Ougonmegami 2-gou and Shimoshirazu) by RNA gel blot analysis. In these cultivars, both the timing and the levels of expression of the CS-ACS2 transcript were correlated with the development of female flowers at the nodes. Furthermore, the timing of the induction of expression of the CS-ACS2 gene at the apex corresponded to that of the action of ethylene in induction of the first female flower at the apex of gynoecious cucumber plants. These results suggest that the development of female flowers might be regulated by the level of CS-ACS2 mRNA at the apex.

Amino Acid Sequence↗
PubMed1996

Urinary incontinence in elderly inpatients in Japan: a comparison between general and geriatric hospitals.

This is the first multi-hospital epidemiological study to elucidate the prevalence and characteristics of urinary incontinence in elderly inpatients throughout Japan. Of the 2586 subjects to whom questionnaires were issued, 1563 (60.4%) (65 to 102 years old, 598 men, 965 women) were suitable for the study. A total of 817 patients were hospitalized in geriatric hospitals; that is, geriatric facilities under the regulation of the Department of Health and Welfare. All patients were evaluated by medical doctors for the following items: age, sex, duration of hospitalization, activities of daily living, medical diagnosis, presence or absence of urinary incontinence, type of urinary incontinence, and therapy for urinary incontinence. The prevalence of urinary incontinence in patients under 70, 70-79, 80-89, and over 90 years old was 59.3%, 67.7%, 79.8%, and 82.2%, respectively. Overall, 1142 patients (72.0%) suffered from urinary incontinence. Cerebrovascular disease was the major cause of admission to hospital in patients with urinary incontinence (37.0%). The most frequent type of urinary incontinence was functional urinary incontinence in patients who were mentally and/or physically unable to go to the bathroom without aid (21.5%). Specifically, 38.1% of patients in geriatric hospitals were diagnosed as having functional urinary incontinence, in contrast to only 3.9% of patients in non-geriatric units. In patients with dementia, 88.7% were incontinent, whereas in patients without dementia, the prevalence of urinary incontinence was much lower (51.5%, p < 0.001). Another predisposing factor for urinary incontinence was urinary tract infection. The prevalence of urinary incontinence in patients with and without urinary tract infection was 87.8% and 59.5%, respectively (p < 0.001). Almost all patients with poor activities of daily living (who were bedridden) suffered from urinary incontinence (98.5%). On the other hand, urinary incontinence was not so frequent in patients who could walk (26.9%). Pad (42.8%) and indwelling bladder catheter (18.3%) were the major means of management of incontinence, whereas behavioral therapy (4.9%) and surgery (0.5%) were not common. These results suggest that elderly patients with treatable urinary incontinence do not receive adequate therapy in Japan.

Activities of Daily Living↗
PubMed1994

Regulation of expression of the genes for a sex pheromone by an inducer of the sex pheromone in the Closterium peracerosum-strigosum-littorale complex.

A sex pheromone, protoplast-release-inducing protein (PR-IP), of the Closterium peracerosum-strigosum-littorale complex is known to induce the release of protoplasts from mating-type minus (Mt-) cells during sexual reproduction and to have two subunit polypeptides of 19 and 42 kDa. Here, we describe the regulation mechanism for the release of the PR-IP. The sex pheromone was fractionated to yield subunits of 19 and 42 kDa, respectively, and each subunit was treated with V8 protease and with CNBr. By reference to the partial amino-acid sequences of the digested polypeptides, oligo nucleotides were synthesized and used as primers for the combined reverse transcription-polymerase chain reaction. Amplified fragments of DNA, of 130 bp in the case of the 19-kDa subunit and of 330 bp in the case of the 42-kDa subunit, were obtained, sequenced, and used as probes to identify the respective transcripts. From the results of Northern hybridization, the sizes of transcripts were estimated to be 1.2 kb for the 19-kDa subunit and 1.4 kb for the 42-kDa subunit. These transcripts appeared transiently only when mating-type plus (mt+) cells were treated with another sex pheromone (PR-IP Inducer) for more than 4 h in the light. By immunoblotting with anti-42-kDa-subunit antiserum, it was shown that PR-IP accumulated gradually in the medium but not in the mt+ cells after treatment with PR-IP inducer in the light.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

The enzymatic formation of 1 alpha,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3 in the liver of fetal rats.

We have confirmed the existence of 25-hydroxyvitamin D3 (25-OH-D3)-1 alpha-hydroxylase in the liver of fetal rats, in addition to that in the kidney, by in vitro experiments. The findings are similar to those in the fish liver as reported previously (Takeuchi et al., Life Sci. 32, 275-282, 1991). When [3H]-25-OH-D3 was incubated with liver homogenates of vitamin D-deficient fetal rats, a peak corresponding to [3H]-1 alpha,25-dihydroxyvitamin D3 (1,25-(OH)2D3) was observed in the profile of high-performance liquid chromatography (HPLC). The formation of the metabolite was confirmed by thermal isomerization into the pre-isomer, binding affinity to the receptor and mass fragmentography. Lineweaver-Burk plot analysis of mitochondrial 25-OH-D3-1 alpha-hydroxylase in the liver gave an apparent Km value of approximately 2 microM of 25-OH-D3 and a Vmax value of 0.2 pmol of 1,25(OH)2D3/30 min/mg protein. These findings suggest that the enzyme in the liver disappeared with the growth of the fetus and became predominant in the kidney of mature rats.

Aging↗
PubMed1992

Simultaneous cardio-cerebral ultrasonic measurement technique for assessing the interrelationship between cardiac and cerebral circulations in elderly subjects: a preliminary study.

To assess the interrelationship between the cardiac and cerebral circulations, simultaneous measurements of cardiac output (CO) and common carotid blood flow volume (CCBFV) was performed by M-mode echocardiography of the left ventricle, and quantitative ultrasonic Doppler blood flowmetry of the common carotid artery. The subjects studied were 12 healthy persons living in a home for the elderly ranging in age from 62 to 99 years. These subjects were divided into two groups: those who were in their 90s (Group I, 5 females) with a mean age of 93.6 +/- 3.5 years (mean +/- SD), and those who were in their 60s to 80s (Group II, 1 male and 6 females) with a mean age of 77.1 +/- 8.1 years. The average CO in Group I was 2.85 +/- 0.37 L/min, and 4.18 +/- 0.52 L/min in Group II. The average CCBFV was 4.74 +/- 0.64 dl/min in Group I, and 4.44 +/- 1.01 dl/min in Group II. The ratio of CCBFV to CO was 16.6 +/- 1.32% in Group I, and 10.6 +/- 1.45% in group II. Good linear correlations of y = 1.44x +0.65 (r = 0.82) in Group I and y = 1.58x - 2.15 (r = 0.81, p less than 0.05) in Group II were observed between CO (x) and CCBFV (y). No such close correlations were observed between CCBFV and other indices of left ventricular function such as circumferential fiber shortening or fractional shortening of the diameter of the left ventricle (r less than or equal to 0.56, p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Echocardiographic assessment of the effect of aging on the diastolic and systolic functions of the left ventricle].

The effects of aging on the diastolic and systolic functions of the left ventricle were studied by echocardiography as follows. (1). Maximum velocity of circumferential fiber lengthening (negative peak Vcf) and shortening (peak Vcf) was assessed by digital M-mode echocardiography in 20 healthy young subjects and 26 healthy elderly subjects. The mean value of negative peak Vcf (-cir/sec) was -3.87 +/- 0.85 in the 20's. -4.48 +/- 1.14 in the 30's, -3.71 +/- 1.21 in the 40's, -2.70 +/- 0.90 in the 60's, -2.57 +/- 0.64 in the 70's, -2.33 +/- 0.77 in the 80's and -2.57 +/- 0.65 in the 90's showing significant difference among young and elderly groups (p less than 0.05- p less than 0.005). The mean value of peak Vcf showed no significant difference among young and elderly groups except for the group in the 30's which showed significant (p less than 0.05) difference between other groups. (2). Indices of the left ventricular systolic and diastolic functions were calculated by standard M-mode echocardiographic technique in 227 healthy subjects from 5 to 94 years in age by dividing them into 3 young groups and 4 elderly groups. As for the left ventricular internal diameters a tendency of increase was observed in the end diastolic diameter of the left ventricle in accordance with ageing. Fractional shortening of the left ventricular diameter which ranged from 36.2% to 36.7% in the 3 young groups and 36.9 to 40.3% in the 4 elderly groups and cardiac output showed no age dependent decrease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Osteopenic changes in high sugar diet-induced diabetic rabbits (HSDD-R).

Rabbits maintained on a persistent high sugar diet eventually develop diabetes mellitus with a marked decline in glucose tolerance, but no studies have been conducted on the associated bone changes in these high sugar diet-induced diabetic rabbits (HSDD-R). Radiographs have revealed a significant thinning of the femoral cortex of these rabbits with markedly decreased bone mass. Scanning electron microscopy of the femoral cortex using the freeze-fractured technique have revealed the loss of a typical structure of Haversian canals and the surrounding concentric and radiating lamellar bones and also the loss of fibrous components in the section. The border created by the cement line was indistinct and resulted in amorphous changes. Formation of heterogenous bundles of fibrous components different from the usual reticular structure was seen within the subendothelial space of the Haversian canals. These results indicate that qualitative changes can apparently occur in the bone along with the development of osteopenia in the diabetic state.

Animals↗
PubMed1991

[Pathophysiological study of corona radiata infarcts by clinically available diagnostic methods].

The authors evaluated 18 patients who presented with corona radiata infarction, one of the 'water-shed infarctions', on CT and/or MRI to determine its etiology and pathophysiology using cerebral angiography, single-photon emission computed tomography (SPECT), and tests of hemostatic function including hematocrit, platelet aggregation and adhesiveness. On angiography, 8 of these 18 patients had ulcerative lesions in the common carotid artery bifurcation with or without minimal stenosis and exhibited no or a minimal area of hypoperfusion localized to the corona radiata on SPECT. In these, microembolism from the lesions at the common carotid bifurcation seemed play an important role in the genesis of corona radiata infarction. In 7 of the remaining 10 patients, cerebral angiography showed occlusive lesions of the internal carotid artery around its origin in 3, more than 90% stenosis of the internal carotid artery in 1, severe stenosis of the M1 segment of the middle cerebral artery in 2, and M1 occlusion in 1. In 5 of these 7, SPECT demonstrated a larger area of hypoperfusion than the corona radiata in the involved hemisphere. In the remaining 2, SPECT demonstrated a hypoperfusion area localized to the corona radiata. In all 7, the hematocrit was elevated. A collateral blood supply was visualized in 5 of 7 on cerebral angiography. In these 7 patients, hemodynamic disturbance was considered to contribute to the pathogenesis of infarction in the corona radiata. In the final three patients, cerebral angiography showed significant occlusive lesions in the main trunk of the cerebral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗