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Biomedical subjects

M Moriguchi

Publications and source records attributed to M Moriguchi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cloning and sequencing of a gene encoding D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 and expression of the gene in Escherichia coli.

The gene encoding the D-aminoacylase of Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was cloned and its complete nucleotide sequence was identified. The D-aminoacylase structural gene consists of 1452 nucleotides and encodes 484 amino acid residues. The molecular weight of D-aminoacylase was calculated to be 51,918. This value agreed well with the apparent molecular weight of 52,000 found for the purified enzyme from Alcaligenes A-6 by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). The N-terminal amino acid sequence (NH2-SQSDSQPFDLLRAG-) predicted by the nucleotide sequence exactly matched those of the purified D-aminoacylase both from Alcaligenes A-6 and from cloned Escherichia coli (E. coli), with the exception of the removal of the N-terminal methionine processed after translation. The purified recombinant enzyme showed almost the same enzymatic properties as the native enzyme from Alcaligenes A-6. Alcaligenes A-6 D-aminoacylase showed 25-29% homology with L-aminoacylases from Bacillus stearothermophilus, porcine and humans.

Alcaligenes↗
PubMed1994

Effect of beta-carotene, sodium ascorbate and cellulose on 1,2-dimethylhydrazine-induced intestinal carcinogenesis in rats.

Male Sprague-Dawley rats were fed a diet containing either 0.005% beta-carotene, 0.02% sodium ascorbate or 1.5% cellulose for 14 weeks. Beginning on day 3, all animals were also given weekly subcutaneous injections of 1,2-dimethylhydrazine (DMH; 20 mg/kg body wt.) throughout a 12-week period. The experimental diet was continued for an additional 14 weeks. At the end of the 26th week, surviving animals were sacrificed and the incidence of intestinal carcinomas was examined. A significantly lower incidence of carcinomas was observed in the beta-carotene-fed group (55.0%), compared with that in the control group given DMH (82.1%).

1,2-Dimethylhydrazine↗
PubMed1994

Purification and characterization of thermostable beta-N-acetylhexosaminidase of Bacillus stearothermophilus CH-4 isolated from chitin-containing compost.

Thermostable exochitinase was purified to homogeneity from the culture fluid of Bacillus stearothermophilus CH-4, which was isolated from agricultural compost containing shrimp and crabs. The enzyme was a single polypeptide with a molecular mass of 74 kDa, and the N-terminal amino acid sequence was WDKVGVTDLI ISLNIPEADAVVVGMTLQLQALHLY. The enzyme specifically hydrolyzed C-4 beta-anomeric bonding of N-acetylchitooligosaccharides, as well as their p-nitrophenyl (pNP) derivatives. The enzyme also hydrolyzed pNP-beta-N-acetyl-D-galactosaminide (26% of the activity of pNP-beta-N-acetyl-D-glucosaminide). These results indicated that the enzyme is a beta-N-acetylhexosaminidase (EC 3.2.1.52). Kms for acetylchitooligosaccharides were 1 x 10(-4) to 6 x 10(-4) M, while those for the pNP derivatives were 4 x 10(-3) to 8 x 10(-3) M. The optimum temperature of the enzyme was 75 degrees C, and it retained 100 and 28% reactivity after heating at 60 and 80 degrees C, respectively. The enzyme exhibited 15 to 20% activity in a reaction mixture containing 80% organic solvents and maintained 91% of its original activity after exposure to 8 M urea. The optimum and stable pH was around 6.5. Fe2+, Zn2+, and Ca2+ activated the enzyme, but Hg2+ was inhibitory. N-Acetyl-D-glucosamine inhibited the enzyme competitively (Ki = 4.3 x 10(-4) M), whereas N-acetyl-D-galactosamine did not; in contrast, D-glucosamine and D-galactosamine activated it.

Amino Acid Sequence↗
PubMed1994

[The significance of portal infusion chemotherapy for prevention of recurrence in residual liver after hepatectomy for metastases from colorectal cancer].

We performed portal infusion chemotherapy using a reservoir for prevention of recurrence in residual liver after hepatectomy for metastases from colo-rectal cancer. To study the usefulness of portal infusion chemotherapy, the period from hepatectomy to recurrence in residual liver was investigated by three treatment groups for H2 cases; (a) a group of systemic chemotherapy, (b) a group of arterial infusion chemotherapy and (c) a portal infusion chemotherapy group. Treatment in (a) group was for 204 +/- 98.2 days (n = 6), in (b) group for 343.0 +/- 238.3 days (n = 8) and in (c) group for 961.0 +/- 1,172.4 days (n = 5). There was no statistically significant difference in the three groups, but (c) group had a better result in recurrence in residual liver. As for prevention of recurrence in residual liver after re-hepatectomy, there was no significant difference in the three groups, but (c) group had the longest survival.

Aged↗
PubMed1993

Purification and characterization of novel N-acyl-D-aspartate amidohydrolase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6.

Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) produced N-acyl-D-aspartate amidohydrolase (D-AAase) in the presence of N-acetyl-D-aspartate as an inducer. The enzyme was purified to homogeneity. The enzyme had a molecular mass of 56 kDa and was shown by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) to be a monomer. The isoelectric point was 4.8. The enzyme had maximal activity at pH 7.5 to 8.0 and 50 degrees C, and was stable at pH 8.0 and up to 45 degrees C. N-Formyl (Km = 12.5 mM), N-acetyl (Km = 2.52 mM), N-propionyl (Km = 0.194 mM), N-butyryl (Km = 0.033 mM), and N-glycyl (Km = 1.11 mM) derivatives of D-aspartate were hydrolyzed, but N-carbobenzoyl-D-aspartate, N-acetyl-L-aspartate, and N-acetyl-D-glutamate were not substrates. The enzyme was inhibited by both divalent cations (Hg2+, Ni2+, Cu2+) and thiol reagents (N-ethylmaleimide, iodoacetic acid, dithiothreitol, and p-chloromercuribenzoic acid). The N-terminal amino acid sequence and amino acid composition were analyzed.

Alcaligenes↗
PubMed1993

Production, purification, and characterization of D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6.

The best inducers for D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) were a poor substrate, N-acetyl-gamma-methyl-D-leucine, and an inhibitor, N-acetyl-D-alloisoleucine. The enzyme has been homogeneously purified. The molecular weight of the native enzyme was estimated to be 58,000 by gel filtration. A subunit molecular weight of 52,000 was measured by SDS-PAGE, indicating that the native protein is a monomer. The isoelectric point was 5.2. The enzyme was specific to the D-isomer and hydrolyzed N-acetyl derivatives of D-leucine, D-phenylalanine, D-norleucine, D-methionine, and D-valine, and also N-formyl, N-butyryl, and N-propionyl derivatives of D-leucine. The Km for N-acetyl-D-leucine was 9.8 mM. The optimum pH and temperature were 7.0 and 50 degrees C, respectively. The stabilities of pH and temperature were 8.1 and 40 degrees C. D-Aminoacylases from three species of the genus Alcaligenes differ in inducer and substrate specificities, but are similar with respect to molecular weight and N-terminal amino acid sequence.

Alcaligenes↗
PubMed1992

Nitric oxide can modify amino acid residues in proteins.

Nitric oxide derived from sodium nitroprusside binds to the heme moiety of hemoglobin and also modifies some functional groups in the protein. As hemoglobin concentration is increased, globin modification is decreased presumably due to formation of the NO complex with heme. The SH groups of hemoglobin are probably not involved in the formation of the stable product formed by NO. In the presence of inositol hexaphosphate, which binds preferentially in the cleft between the two beta-chains of hemoglobin, formation of one modified derivative was selectively reduced. With hemoglobin specifically blocked on its N-terminal residues, globin modification was also significantly reduced. Carbonic anhydrase, which is blocked at its N-terminus, was also refractory to modification. The results suggest that the N-terminal groups of some proteins can be modified by nitric oxide, perhaps by deamination.

Allosteric Regulation↗
PubMed1992

Effects of theophylline on the selective increases in intratumoral blood flow induced by intracarotid infusion of adenosine and adenosine triphosphate in C6 glioma-transplanted rat brains.

We have previously reported that the intracarotid administration of adenosine or adenosine triphosphate (ATP) selectively increased blood flow in intracerebrally transplanted C6 glioma cells in rats, using the hydrogen clearance method. In the present paper, we studied the difference between the effects of adenosine and ATP, using theophylline, a P1 purinoceptor blocker. The selective enhancement of the tumor blood flow by intracarotid administration of adenosine was almost totally inhibited by theophylline. In contrast, the selective enhancement by ATP was shown definitely not to be inhibited by theophylline. Therefore, it is supposed that the selective increase of intratumoral blood flow by the intracarotid infusion of adenosine is closely related to the P1 purinoceptor, and the effect of the intracarotid infusion of ATP is composed not only of the effect as degraded into adenosine but also of the effect of ATP itself.

Adenosine↗
PubMed1992

Effects of L-NMMA and L-NNA on the selective ATP-induced enhancement of intratumoral blood flow.

We studied the effects of NG-monomethyl-L-arginine (L-NMMA) and N omega-nitro-L-arginine (L-NNA) on the selective ATP and adenosine-induced enhancement of intratumoral blood flow in rats measured by the hydrogen clearance method. Both adenosine and ATP produced a selective enhancement of the intratumoral blood flow. Neither L-NMMA nor L-NNA had a significant effect on either the CBF or the intratumoral blood flow. Adenosine-induced enhancement was not inhibited by L-NMMA or L-NNA. On the other hand, the ATP-induced enhancement was totally inhibited by both L-NMMA and L-NNA. The inhibitory action of L-NMMA against ATP was blocked by L-arginine, but not by D-arginine. It is suggested that the ATP-induced increase of intratumoral blood flow is evoked by nitric oxide synthesized from the endothelium of the intratumoral blood vessels.

Adenosine↗
PubMed1992

Microvasculature of normal and hydropic labyrinth.

The microvasculature of the inner ear in guinea pigs and humans was observed with a scanning electron microscope using corrosion casting method. Alterations in the inner ear vasculature which occurred in association with experimental endolymphatic hydrops were also investigated. The results thus obtained are summarized as follows: 1. In the cochlea and vestibule, the arteries, coiled arterioles, and the veins are endowed with their respective characteristic morphologic features and play a role in the regulatory mechanisms of circulation. 2. The point in humans which is most different from guinea pigs was that coiled arterioles in the cochlea and the coil-like traveling of the anterior vestibular artery is not outstanding. 3. Arteriovenous anastomoses were demonstrated to exist in lateral wall of cochlea and utricular macula, a finding suggesting the existence of a regulatory mechanism for local blood flow. 4. Endolymphatic hydrops was noted to be preferentially associated with vascular abnormalities in the lateral wall of the cochlear duct and in the saccular macula, among other vestibular structures.

Animals↗
PubMed1992

[Clinical evaluation of serum levels of monomeric dimeric and tetrameric pseudocholinesterases in patients with various liver diseases].

Serum levels of monomeric, dimeric and tetrameric pseudocholinesterases were measured by means of enzyme-linked immunosorbent assay in patients with various liver diseases and normal controls in order to evaluate their clinical significance. In patients with liver cirrhosis, serum levels of monomeric, dimeric and tetrameric were significantly lower than those in normal controls, patients with fatty liver and chronic hepatitis. The ratio of monomeric and dimeric to tetrameric in patients with liver cirrhosis was also significantly lower than that in normal controls, patients with fatty liver and chronic hepatitis. Serum levels of tetrameric, dimeric and monomeric were not significantly higher in the patients with fatty liver than in normal controls, but the ratio of monomeric and dimeric to tetrameric was significantly higher in patients with fatty liver than that in normal controls, patients with chronic hepatitis and liver cirrhosis. These findings suggest that the selective determinations of serum levels of monomeric, dimeric and tetrameric pseudocholinesterases are useful to estimate the metabolism of fat and protein in various liver diseases.

Adult↗
PubMed1991

Purification and characterization of N-acyl-D-glutamate deacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6.

The purification and properties of N-acyl-D-glutamate deacylase from the cell extracts of Alcaligenes xylosoxydans subsp. xylosoxydans A-6 were studied. The two active fractions (peaks I and II) were obtained by a Mono Q column chromatography. The predominant enzyme (peak I) has been purified, 1960-fold to homogeneity and characterized. The enzyme was a monomer with a molecular weight of 59,000. The optimum pH and the isoelectric point were 8.0 and 5.5, respectively. The enzyme catalyzed the hydrolysis of N-acyl derivatives of D-glutamate. The Kms for N-acetyl, N-butyryl and N-propionyl derivatives of D-glutamate were 0.129, 0.066 and 0.01 mM, respectively.

Alcaligenes↗
PubMed1991

Production and characterization of N-acyl-D-glutamate amidohydrolase from Pseudomonas sp. strain 5f-1.

N-Acyl-D-glutamate amidohydrolase from Pseudomonas sp. strain 5f-1 was inducibly produced by D isomers of N-acetylglutamate, glutamate, aspartate, and asparagine. The enzyme has been purified to homogeneity by DEAE-cellulose, (NH4)2SO4 fractionation, and chromatofocusing followed by gel filtration on a Sephadex G-100 column. The enzyme was a monomer with molecular weight of 55,000. The enzyme activity was optimal at pH 6.5 to 7.5 and 45 degrees C. The isoelectric point and the pH stability were 8.8 and 9.0, respectively. N-Formyl, N-acetyl, N-butyryl, N-propionyl, N-chloroacetyl derivatives of D-glutamate and glycyl-D-glutamate were substrates for the enzyme. At pH 6.5 in 100 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer at 30 degrees C, a Km of 6.67 mM and a Vmax of 662 mumol/min/mg of protein for N-acetyl-D-glutamate were obtained. None of the metal ions stimulated the enzyme activity. Na+, K+, Mg2+, and Ba2+ acted as stabilizers. Hg2+, Cu2+, Zn2+, Fe3+, and EDTA were strongly inhibitory.

Amidohydrolases↗
PubMed1991

The influence of noise exposure on endolymphatic hydrops. An experimental study.

The influence of noise exposure on endolymphatic hydrops was examined morphologically. Endolymphatic hydrops was produced experimentally in guinea pigs by means of endolymphatic sac obliteration. Approximately 2 months later, the animals were subjected to noise exposure for 2 h and, as a result, the following findings were obtained: Vascular and circulatory disturbances in the 3rd and 4th turns of cochlea, i.e., vasoconstriction-like changes in the upper coiled arterioles and capillaries in the stria vascularis, as well as blood cell sludge. In addition, the outer hair cells in Corti's organ at the same turns disappeared sporadically. No changes were observed in the opposite, control, ear of the same animal which was free from endolymphatic hydrops. On the basis of these results, it is argued that endolymphatic hydropic ears are highly vulnerable to noise exposure.

Animals↗
PubMed1991

Development of inner ear vessels. A scanning electron microscopic study.

The development of the inner ear vessels of guinea pigs were studied by SEM. Employing 32- to 55-gestational-day-old guinea pig embryos, corrosion casts of inner ear blood vessels were prepared using Mercox resin and then observed by scanning electron microscopy. Between the 35th and 40th gestational days, the vascular structure of the vestibule was sufficiently developed, but the capillary network in the wall of the cochlea remained immature. Thus, in the guinea pig, the development of the vestibular structure precedes the development of the cochlear vessels. Moreover, at both sites, the density of the embryonic blood vessels was high, and the vessels were believed to transport a large blood flow. From about the 40th day of gestation, the coiled vessels and the capillary network in the lateral wall of the cochlea underwent rapid development, and the vascular structure in both the vestibule and cochlea was nearly complete by the time of birth.

Animals↗
PubMed1991

Measurement of inner ear vessel diameters with casting method.

Under scanning electron microscopy we measured the vessel diameters of every part of the inner ear in rats and guinea pigs with casting method using Mercox resin. There were only few errors in measurement values in the same part of the same vessel with this method. The vessels of the stria vascularis were much larger in diameter than any other capillaries in the lateral wall of the cochlea in the rat and especially in the guinea pig. It is suggested that the velocity of the blood flow in the stria vascularis is slow and that the stria vascularis can retain much blood. The anterior vestibular artery (AVA) was larger in diameter than the posterior vestibular artery (PVA). The AVA supplies the large area in the vestibule whereas the PVA supplies the small area.

Animals↗
PubMed1991

Distribution of arteries from brain stem to inner ear around the internal auditory canal.

In the present work, casts of vessels surrounding the internal auditory canal of the guinea pig were subjected to scanning electron microscopic examination. Most casts were prepared by the resin-casting method using Mercox resin. The following results were obtained: 1) Individual variations and bilateral asymmetry were observed in the anterior inferior cerebellar artery (AICA), which branches off the basilar artery (BA); 2) Frequently a loop the AICA was found in the CP-angle and internal auditory canal; 3) The internal auditory artery (IAA) did not always originate in AICA but sometimes arose directly from BA; 4) In common cochlear artery and anterior vestibular artery, there were individual differences and asymmetric branching patterns on both sides; 5) We conclude that inner ear disease of vascular origin may be influenced by individual variations in the BA and its branches.

Animals↗