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S Moriya

Publications and source records attributed to S Moriya.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Effect of endothelin-1 on ocular circulation].

Endothelin (ET)-1, a potent vasoconstrictor which was discovered recently, might be involved in the regulation of ocular circulation. In this paper, we studied the effects of ET-1 on capillary blood flow of the optic nerve head and choroid in rabbits, using a hydrogen gas clearance flowmeter. Intravitreal injection of 0.1 ml of ET-1 at 10(-5) M and 10(-6) M caused a significant decrease in blood flow, which in the optic nerve head continued more than 3 hours, but in the choroid recovered at 3 hours after the injection (maximum decrease occurred at 75 minutes and at 30-60 minutes, respectively). Intraocular pressure was reduced as the time passed. Intravenous administration of 10(-10) mol/kg of ET-1 induced a reduction in blood flow, which in the optic nerve head continued more than 3 hours, but in the choroid recovered at 90 minutes after the administration. Intraocular pressure was reduced during 3 hours' observation. The decrease in blood flow in the optic nerve head was inhibited by previous administration of calcium antagonist (nicardipine), so the calcium channel was thought to be involved in this reaction.

Animals↗
PubMed1992

Cloning of an autonomously replicating sequence (ars) from the Bacillus subtilis chromosome.

Cloning of an autonomously replicating sequence (ars) from the origin region of Bacillus subtilis was previously unsuccessful because of the strong incompatibility exerted by sequences located within the oriC region. Using an ars searching vector which would be selective for drug resistance even at one copy per cell, and by cloning large fragments covering as much as possible of the oriC region, we have succeeded in isolating ars fragments from the origin region of the chromosome. The minimum essential fragment contains two DnaA-box regions (non-translatable regions containing multiple repeats of DnaA-box) separated by the dnaA gene. Neither one of the DnaA-box regions by itself showed ars activity. When constructed as oriC plasmids, the dnaA coding region could be removed without affecting ars activity. The minimum distance between the two DnaA-box regions obtained so far is 274 bp. The copy number of the oriC plasmid is estimated as one per replicating chromosome. These plasmids are unstable and tend to be lost or integrated into chromosome.

Amino Acid Sequence↗
PubMed1992

[Age effects of topical tyramine and cocaine on the pupil].

In order to obtain the age distribution of normal values of the effects of topical tyramine or cocaine on the pupil, we measured the pupillary light reflexes of 50 normal volunteers before and 45 minutes (tyramine) or 90 minutes (cocaine) after the topical instillation in right eyes. Left eyes were used as controls. An infrared videopupillogram (HTV-C301) was used. Topical tyramine as well as cocaine caused mydriasis, increase of maximum %-velocity of dilatation (%-VDmax), reduction of %-amplitude of constriction (%-A) and decrease of maximum %-velocity of constriction (%-VCmax). These alternations of pupillary parameters coincided with the changes induced by topical epinephrine. The effects of tyramine or cocaine significantly increased as the age of the subjects increased, though the increase of %-VDmax caused by cocaine was only related to age. Age-related augmentation of pupillary changes were also been observed in a previous study using topical epinephrine or topical pilocarpine which concluded that the effects of any topical autonomics were increased by aging. No physiological senile Horner's syndrome was detected. It was concluded that the age-related augmentation of pupillary changes caused by topical autonomics probably resulted from the increment of corneal permeability in the aged which was confirmed in the previous fluorophotometric study by the authors following topical fluorescein administration. It is possible to assess the pupillary sensitivity to topical adrenergics of the patients with bilateral Horner's syndrome by comparing the age-related normal values obtained in this study.

Adolescent↗
PubMed1990

Isolation of a dnaA mutant of Bacillus subtilis defective in initiation of replication: amount of DnaA protein determines cells' initiation potential.

The dnaA gene is essential for initiation of chromosomal replication in Escherichia coli. A gene homologous with the E. coli dnaA was found in the replication origin region of the Bacillus subtilis chromosome. We have now isolated a temperature sensitive mutant of the B. subtilis dnaA by in vitro mutagenesis of the cloned gene. At a nonpermissive temperature, 49 degrees C, DNA replication stops completely after 60% increase in a rich medium, while cell mass continues to increase exponentially at 2.5 times the rate at 30 degrees C. A ratio of gene frequency between purA (origin marker) and metB (terminus marker) changes gradually from 2.7 at 30 degrees C to 1.0 in 45 min at 49 degrees C, indicating completion of the ongoing replication cycle. Upon the temperature shift down to 30 degrees C after the incubation at 49 degrees C for 60 min, DNA replication resumes without delay, and the purA/metB ratio increases rapidly to 6, i.e. consecutive initiation of more than two rounds of replication. Addition of chloramphenicol at the time of the temperature shift down did not inhibit the increase in the purA/metB ratio, while rifampicin inhibited the re-initiation completely. The mutation is a single base change from C to T in the dnaA gene resulting in an amino acid substitution from Ser to Phe in the DnaA protein. The mutation was responsible for both temperature sensitive growth and the defect in initiation of chromosomal replication. We observed a remarkable correlation between the amount of DnaA protein and the amount of initiation potential accumulated during incubation at the non-permissive temperature.

Bacillus subtilis↗
PubMed1990

Purification and characterization of an initiation protein for chromosomal replication, DnaA, in Bacillus subtilis.

Bacillus subtilis DnaA protein was overproduced by a recombinant plasmid containing B. subtilis dnaA gene in a mutant Escherichia coli strain which is deficient in its own DnaA and RNaseH. The protein was purified to near homogeneity as judged by SDS-PAGE analysis. The purified protein binds preferentially to DNA fragments which are derived from flanking regions of the B. subtilis dnaA gene and contain various numbers of the repeat of 9 nucleotides, TTATCCACA, and closely related sequences. The purified protein binds ATP with high affinity (Kd = 0.02 microM) and ADP with less affinity, but does not bind cAMP. ATP stimulates the binding of the DnaA protein to the repeated sequences. DNaseI footprinting experiments demonstrated that the DnaA bound first to the consensus 9-mer and then to sequences differing by one base from the consensus. Sequences differing by two bases from the consensus were bound by the DnaA only when they were located contiguous to the strong DnaA-boxes. The three DnaA-box clusters, incA, incB, and incC, derived from the replication origin region of the B. subtilis chromosome showed different levels of growth inhibition when they were introduced into B. subtilis. We demonstrated by assaying competition for DnaA-binding among the DnaA-box clusters that there is a good correlation between the degree of growth inhibition by DnaA-box clusters in vivo and their strength of binding to the DNaA protein in vitro.

Adenosine Triphosphate↗
PubMed1990

[A re-evaluation of pupillary sensitivity to autonomics in diabetic patients].

It is well known that pupils of diabetic patients are supersensitive to topical administration of autonomics, and whether the penetration of instilled drugs into the anterior chamber is high or not is an important problem from a causal point of view. Fluorescein penetration into the anterior chamber after topical instillation was examined by fluorophotometry in 39 diabetic patients aged 30-70 and 26 age-matched healthy subjects. Penetration increased in correlation with aging in both groups. Though there was no significant difference between the distribution of fluorescein penetration in patients with DR-Scott 0, I, II and those in healthy subjects, patients with DR-Scott III.V showed higher penetration than the former in each age-group. A study of the relation between the pupillary sensitivity to diluted solution of pilocarpine and fluorescein penetration in diabetic patients revealed significant correlation (r = 0.48, p less than 0.05) in cases aged less than 50. As a result, penetration of drug into the anterior chamber was considered to be a significant parameter of pupillary sensitivity.

Administration, Topical↗
PubMed1988

Regulation of initiation of the chromosomal replication by DnaA-boxes in the origin region of the Bacillus subtilis chromosome.

A gene homologous to the Escherichia coli dnaA gene and two flanking 'regulatory' regions which contain nine and four DnaA-boxes respectively, are located in the replication origin region of the Bacillus subtilis chromosome. Attempts to isolate an autonomously replicating fragment from these 'regulatory' regions in order to identify oriC have been unsuccessful because the DnaA-box-containing regions strongly inhibited plasmid transformation particularly when inserted into a high-copy number plasmid pUB110. Using two plasmids differing in copy number, the two regions were subdivided into three regions, A, B and C, each containing five, four and four DnaA-boxes respectively, which differed in level of inhibition of transformation. Region C is downstream of the 'dnaA' gene and inhibits transformation in high-copy but not in low-copy number plasmids. When a part of the DnaA-boxes was deleted from the incompatible plasmids, they became transformable and produced slow-growing transformants in which the initiation frequency of chromosomal replication was selectively reduced. Fast-growing revertants were found containing the same number of plasmids as the parent but with single base changes in the DnaA-boxes. These mutations were in the most highly conserved bases of the DnaA-box sequence. This indicates that a sequence-specific interaction of the DnaA-box, probably with the B. subtilis DnaA protein is responsible for the observed incompatibility and thus appears to be involved in control of initiation frequency of the chromosomal replication.

Bacillus subtilis↗
PubMed1986

Nucleotide sequence and organization of dnaB gene and neighbouring genes on the Bacillus subtilis chromosome.

A region of the Bacillus subtilis chromosome containing dnaB, a gene essential for the initiation of chromosomal replication in B. subtilis, was cloned and nucleotide sequence of some 5000bp determined. The region consists of 4 open reading frames (ORFs) possibly comprising a single transcriptional unit. Two dnaB mutations, dnaB27 and dnaB19 were located within the first ORF which would give rise to a protein of 472 amino acids. The dnaB27 mutation involves codon at the position of 122 (replacement of Asp by Asn) close to a DNA binding domain and the dnaB19 codon 379 (replacement of Ala by Thr) close to a region rich in charged amino acids which may be alpha helical. The third ORF in the same transcriptional unit would produce a hydrophobic protein which might be involved in the DNA-membrane binding function of dnaB gene. No homologous Escherichia coli genes have been found.

Amino Acid Sequence↗
PubMed1986

A Bacillus subtilis dnaG mutant harbours a mutation in a gene homologous to the dnaN gene of Escherichia coli.

A dnaG mutation of Bacillus subtilis, dnaG5, was found to be linked closely to recF. We have reported previously that two putative dna genes, 'dnaA' and 'dnaN', highly homologous to Escherichia coli's dnaA and dnaN, respectively, were located adjacent to recF [Ogasawara et al., EMBO J., 4 (1985) 3345-3350]. Transformation by various fragments cloned from the 'dnaA'-recF region of the wild-type cell revealed that a 532-bp AluI fragment containing 5'-portion of the 'dnaN' gene could transform the dnaG5 mutation. The nucleotide (nt) sequence of the same fragment cloned from the mutant cell shows a single nt change in the ORF of 'dnaN' which in turn causes a single amino acid alteration from Gly to Arg. The 'dnaN' gene is now proven to be a dna gene, mutations in which result in instant arrest of chromosomal replication.

Amino Acid Sequence↗
PubMed1985

Conservation of genes and their organization in the chromosomal replication origin region of Bacillus subtilis and Escherichia coli.

The organization of six open reading frames which were deduced from the nucleotide sequence of some 10 kb from the replication origin region of Bacillus subtilis resembles the organization of the genes in the rnpA-dnaA-gyrB region of the Escherichia coli chromosome. Based on the detection of homology with the E. coli genes the open reading frames were found to represent the Bacillus 'rnpA', 'rpmH', 'dnaA', 'dnaN', recF and gyrB genes. Only the latter two have also been defined by genetic analysis. Two regulatory regions containing nine and four copies of a repeating sequence, DnaA-box, which is identical with the DnaA protein-binding sequence repeated four times in the E. coli origin of replication, flank the 'dnaA' gene of B. subtilis. One or both of them are proposed to function as origins in the initiation of chromosomal replication. Transcription of the 'dnaA' gene of Bacillus starts in one of these regions and appears to be coupled to initiation of chromosomal replication. We propose that the conserved gene organization in the 'dnaA'-'gyrB' region of B. subtilis is representative of the replication origin region of a primordial replicon. The oriC sequence of E. coli has either been translocated to its present location 44 kb away from the primordial origin or has independently evolved there.

Amino Acid Sequence↗
PubMed1985

Structure and function of the region of the replication origin of the Bacillus subtilis chromosome. III. Nucleotide sequence of some 10,000 base pairs in the origin region.

Approximately 10,000 nucleotides were sequenced in the oriC region of the Bacillus subtilis chromosome. The first replicating DNA strands are hybridized with a SalI-EcoRI fragment (nucleotide #1206-2954) in one direction (left to right) and an EcoRI-PstI fragment (#2949-4233) in the other. Seven open reading frames (ORF) accompanied with Shine-Dalgarno (SD) sequences were identified. ORF638 and ORF821 were identified as gyrB and gyrA genes respectively based on genetic evidences and amino acid sequence data. Comparison of amino acid sequences revealed that ORF44, ORF446, ORF378 and ORF323 are homologous with rpmH, dnaA, dnaN and recF of Escherichia coli, respectively. Thus, the organization of the ORFs from ORF44 to ORF638 resembles the organization of genes in the rpmH-gyrB region of the E. coli chromosome. Two non-coding regions characteristic for oriC signals were found near the site of initiation of the first replicating DNA. They are composed of repeating sequences whose consensus sequence TTAT(C/A)CACA is identical to that of 4 repeating sequences in the oriC of E. coli.

Amino Acid Sequence↗
PubMed1985

Structure and function of the region of the replication origin of the Bacillus subtilis chromosome. IV. Transcription of the oriC region and expression of DNA gyrase genes and other open reading frames.

We have determined nucleotide sequence of some 10,000 base pairs (bp) in the oriC region of the Bacillus subtilis chromosome. Initiation sites of transcription from this region were determined in vivo by the S1-mapping method. Five major initiation sites were found in the leader sequences of five open reading frames (ORF) deduced from the nucleotide sequence. The sixth site is located inside the ORF323("recF"). Putative promoters were found for each transcript. Function of these promoters was demonstrated in Escherichia coli by the Maxi-cell method using appropriate fragments cloned in pBR vectors. Based on these results, genes in 10,000 bp oriC region are divided into 4 transcriptional units. GyrB composes one unit with two other ORFs, while gyrA constitutes a single unit by itself. The promoters for ORF446("dnaA") and ORF378("dnaN") are located within the putative signal sequences for oriC. Transcription from these promoters is dependent on a dna-initiation gene, dnaB.

Bacillus subtilis↗
PubMed1985

[Granulosa-cell growth factor in oocyte and its transport systems].

The possible existence of granulosa-cell growth factor (GGF) in the oocyte has been investigated using the labelling index (LI) with 3H-Thymidine and the mitotic index (MI) of granulosa cells (G-cells) in mice. The following results were obtained. In preantral follicles the LI increased with the development of the oocyte until its diameter reached the maximum (approximately 90 mu). In preantral follicles with the oocyte diameter below 69 mu, the LI was low and the follicular diameter was small. As the oocyte developed, the LI increased and reached the maximum value when the follicular diameter was approximately 200 mu. Then it decreased a little but maintained a high value. The antrum formation was seen when the follicular diameter was about 300 mu showing no change in LI. In preantral follicles with the oocyte diameter over 80 mu the G-cell near the oocyte had a much higher LI than the distant one. After the antrum formation, the LI and MI of cumulus layers adjacent to the oocyte were three times as great as those of the mural layers. Among the mural cell layers in the antral follicle the layer adjacent to the antrum showed remarkably high LI in comparison with the distant layers. These results suggest that GGF which seems to play a role in the formation of cumulus is secreted with the development of the oocyte. The GGF is transported through two systems the preantral follicle and cumulus layer through the G-cell gap junction and mural layers through the follicular fluid.

Animals↗