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Biomedical subjects

H Takiguchi

Publications and source records attributed to H Takiguchi.

At least 73 records · Page 4Linked to original sources
PubMed1989

DNA homology of surface protein antigen A gene in mutans streptococci.

1. A recombinant plasmid, pYA724, containing an 8.45 kb DNA fragment encoding surface protein antigen A (spaA) from Streptococcus sobrinus 6715 was used to examine the DNA homology of the spaA gene with chromosomal DNA of various mutans streptococci strains. 2. Restriction endonuclease BamHI-digested pYA724 DNA was radio-labeled by nick-translation, and a DNA-DNA hybridization experiment was carried out. pYA724 DNA hybridized with chromosomal DNA of serotypes a, c, d, e, f and g strains, but not with b by dot DNA-hybridization and Southern blot DNA hybridization. 3. Chromosomal DNAs were isolated from several serotype c Streptococcus mutans strains, digested with BamHI, and analyzed by Southern blot DNA hybridization. pYA724 DNA hybridized with different sizes and numbers of BamHI-digested DNA fragments of the chromosomal DNAs. 4. These data indicated that all mutans streptococci strains except serotype b have DNA homologous with the spaA gene, although within the same serotype strain the spaA gene has a diversity of arrangement within the chromosome.

Antigens, Bacterial↗
PubMed1989

[Effect of diglyceride on phospholipase A2 activities in plasma membrane of guinea pig peritoneal macrophases].

The AA release from phospholipids is believed to be controlled by the activation of phospholipase A2 which are probably localized in the plasma membranes. And the considerable interest has been focused on the study of cells of the immune system including macrophages which metabolize arachidonic acid (AA) to prostaglandins, thromboxanes and leukotriens. Recently, it has been reported that phosphatidylinositol (PI) turnover plays an important role in the response to external stimuli in these cells. PI turnover has been accepted as being initiated by the hydrolysis of PI which is catalyzed by the phospholipase C and produced AA. Recently, we demonstrated that PI-specific phospholipase A2 in macrophage plasma membrane directly acted for AA release from PI. On the other hand, diglyceride, which is produced from PI by phospholipase C activation, is known to regulate the several cell functions with a protein kinase C activation. In this report, we examined the effect of diglyceride on phospholipase A2 activities in macrophage plasma membrane. PI-phospholipase A2 and PC-phospholipase A2 activities were stimulated by the addition of diglyceride. In contrast, PE-phospholipase A2 was not affected by diglyceride addition. The results suggested that phospholipase A2 activation was occurred with coupling the diglyceride production via the phospholipase C pathway.

Arachidonic Acid↗
PubMed1989

Diversity of surface protein antigen A gene in the chromosomal DNA of Streptococcus sobrinus.

A recombinant plasmid, pYA724, containing an 8.45-kb DNA fragment encoding surface protein antigen A (spaA) from Streptococcus sobrinus 6715 was used to examine the DNA homology of the spaA gene with chromosomal DNA of Streptococcus sobrinus B13N. Restriction endonuclease BamHI-digested pYA724 DNA was 32P radio-labeled by nick-translation, and a Southern blot DNA-DNA hybridization experiment was carried out. pYA724 DNA hybridized with a BamHI fragment of B13N chromosomal DNA, and the size of this fragment was larger than 8.45 kb. The chromosomal DNA was digested with BamHI-Pst I, BamHI-Hind III, and BamHI-Sal I, and analyzed by Southern blot DNA hybridization. pYA724 DNA hybridized with different sizes and numbers of DNA fragments of B13N chromosomal DNA; however, the sizes were not identical to those of internal fragments expected from the pYA724 restriction map. SpaA gene clone derivative plasmids, pYA745 and pYA756, were digested with EcoRI and Hinc II, respectively, and electrophoresed together with the digested B13N chromosomal DNA on the same gel; then Southern blot analysis was carried out. Fragments with sizes corresponding to the EcoRI or HincII internal fragments of pYA745 and pYA756 were not observed among the B13N fragments. These data indicate that serotype d S. sobrinus B13N has DNA homologous with the spaA gene from serotype g strain 6715, although within the same biotype strain has a diversity of arrangement within the chromosome.

Antigens, Bacterial↗
PubMed1988

Phospholipase A2 in macrophage plasma membrane releases arachidonic acid from phosphatidylinositol.

A high level of arachidonic acid release from [2-14C]arachidonylphosphatidylinositol (PI) was observed at neutral pH (6.0-7.0) in the presence of purified plasma membranes of guinea pig peritoneal macrophages. This activity was at least 10-fold higher than that with arachidonylphosphatidylcholine (PC) or phosphatidylethanolamine (PE) as substrate. The accumulation of [14C]diacylglycerol and [14C]phosphatidic acid was not detected at any time, and arachidonic acid release from [14C]arachidonyldiacylglycerol was not detectable either. The data suggest that arachidonic acid release from PI may not occur via the phospholipase C pathway. In this paper, we demonstrate the possibility that arachidonic acid release from PI at neutral pH in the macrophage plasma membrane is dependent on the action of phospholipase A2 (EC 3.1.1.4) -like activity. The maximum arachidonic acid release was dependent upon both pH and substrate. Particularly, the activity of arachidonic acid release from PI at neutral pH was very high compared with that from PC or PE. We suggest that phosphatidylinositol phospholipase A2 (EC 3.1.1.52) may play an important role in providing arachidonic acid for subsequent metabolic activity in the macrophages.

Animals↗
PubMed1988

Recognition of acidic phospholipase A2 activity in plasma membranes of resident peritoneal macrophages.

Phospholipase (PLase) activities in the plasma membrane of guinea pig peritoneal macrophages were studied, as these enzymes having such activity may be candidates for the release of arachidonic acid (AA) from phosphatidylcholine (PC). An AA release system operating at acidic pH was identified in the macrophage plasma membrane and characterized. This membrane-bound acidic PLase A2 had an optimum pH at 4.5, and enzyme activation was observed in Ca++-free medium; but the maximum activity was found at 0.5 mM Ca++ concentration. The Km value for PC of acidic PLase A2 was 4.2 microM, and a Michaelis-Menten relationship was evident. Calcium might act as a cofactor at some intermediate step during the activation of acidic PLase A2 in light of the uncompetitive manner of Ca++ action. Furthermore, the release of [3H]-AA from preradiolabelled macrophage plasma membranes occurred with the addition of Ca++ at pH 4.5. These data suggest that the acid PLase A2 is a component of the plasma membrane and is not due to lysosomal contamination since membrane-bound acidic PLase A2 properties are opposite to those found for lysosomal PLase A2.

Animals↗
PubMed1987

Rapid procedure for preparation of macrophage plasma membrane.

This report describes a simple and efficient procedure for the isolation of plasma membrane from guinea pig peritoneal macrophages. The use of polycationic beads (Affi-gel 731 beads) facilitates rapid and high-clear separation of plasma membrane within 30 min. The final plasma membrane coated beads fraction has high specific activities of marker enzymes with little contamination with mitochondrial, lysosomal or cytoplasmal markers.

Animals↗
PubMed1987

Cloning and characterization of Streptococcus mutans LM7 plasmid pAM7.

The 5.6-kilobase-pair cryptic plasmid, pAM7, of Streptococcus mutans LM7 was cloned into Escherichia coli plasmids or a shuttle plasmid to examine whether the plasmid encodes bacteriocin. Plasmid pAM7 encoded proteins with molecular weights of 30,000, 22,000, and 12,000, but none of them appeared to be bacteriocin.

Bacterial Proteins↗
PubMed1987

[Effects of glycerol on local cerebral glucose utilization and local cerebral blood flow of hypoxic rats].

Effects of a continuous infusion of glycerol on the hypoxic rat were assessed by measurements of local cerebral glucose utilization and local cerebral blood flow using the quantitative autoradiographic 1-[C-14]-2-deoxyglucose and [C-14]-iodoantipyrine techniques, respectively. Local cerebral glucose utilization of the hypoxic rat was decreased in most of cerebral structures except for the amygdala, septal nucleus and the white matter. Local cerebral glucose utilization of the hypoxic rat treated with glycerol was recovered to the pattern of normal control, although glucose utilization of the nucleus raphe and locus ceruleus was accelerated. Cerebral blood flow of the hypoxic rat was elevated in almost of all measured structures. In particular, blood flow in the substantia nigra and locus ceruleus was increased significantly. The pattern of local cerebral blood flow of the hypoxic rat treated with glycerol was more analogous to that of normal control than of hypoxic rat without treatment. It is suggested that glycerol has beneficial effects by elevating local cerebral glucose utilization inhibited and decreasing local cerebral blood flow overshot on the hypoxic condition.

Animals↗
PubMed1985

Prostaglandin A2 receptor in rat intestinal basolateral plasma membranes.

The specific prostaglandin A2 receptor was presented in rat intestinal basolateral plasma membrane. The dissociation constant was 4.39 X 10(-8) M and the value of the binding capacity was 3.33 pmol/mg protein. [3H]prostaglandin A2 binding was specifically inhibited by Na+ or ATP. The inhibition manners of Na+ and ATP for [3H]prostaglandin A2 binding were of a competitive and noncompetitive type, respectively.

Adenosine Triphosphate↗
PubMed1985

Glycylprolyl dipeptidylaminopeptidase from Bacteroides gingivalis.

Dipeptidyl aminopeptidase activity was found in the culture medium of Bacteroides gingivalis 381. The enzyme, hydrolyzing glycylprolyl-4-methylcoumaryl-7-amide, was purified 750-fold from culture medium by ammonium sulfate precipitation, Sephadex G-200 gel filtration, and DEAE Bio Gel A column chromatography. The molecular weight, determined by gel filtration, was approximately 160,000. The isoelectric point of the enzyme, estimated by isoelectric focusing using polyacrylamide disk gel electrophoresis, was about pH 6.2. The optimum pH of the enzyme was about 8.0, and the Km value was 0.05 mM. The enzyme activity was strongly inhibited by phenylmethylsulfonylfluoride and diisopropylfluorophosphate. The purified enzyme specifically cleaved glycylprolyl dipeptide from partially digested type I collagen.

Bacteroides↗
PubMed1984

Reactions of recoil tritium atoms with toluene and benzonitrile.

Recoil tritium reactions in the aromatic ring were investigated with toluene and benzonitrile in the moderator-free and the C6F6-moderated systems in terms of the intramolecular tritium distribution, the relative tritiation rate, and the isotope effect in toluene. The reactions free from hexafluorobenzene are in essential agreement with non-selective nature shown in hot atom reactions. The addition of the moderator to the systems changes more markedly the uniform labeling to o,p-orientation in toluene than in benzonitrile, and the 1.17 PhCH3/PhCN tritiation rate (in PhCH3-d8/PhCN, 0.942) to the 1.89 PhCH3/PhCN one (in PhCH3-d8/PhCN, 1.51) when the mole ratio of C6F6/substrate is about 100. These findings agree with the electrophilic nature of the tritium at lower energies. The H/D isotope effect in the moderated system is given as 1.89/1.51 or 1.25 and is substantially the same as that (1.24) in the moderator-free system.

Fluorocarbons↗
PubMed1983

The stimulation of macrophage prostaglandin E2 and thromboxane B2 secretion by Streptococcus mutans insoluble glucans.

The effect of insoluble glucan synthesized by Streptococcus mutans on [3H]arachidonate metabolites secretion from peritoneal macrophages was studied. Insoluble glucans stimulated [3H]arachidonate release and secretion of prostaglandin E2 and thromboxane B2 from macrophages. In contrast, commercial soluble glucan (dextran) did not induce [3H]arachidonate release.

Animals↗
PubMed1983

Some properties of prostaglandin E2 receptors in rabbit alveolar bone cell membranes.

[3H]prostaglandin E2 (PGE2) binding receptors exist in rabbit alveolar bone cell membranes. The presence of high (Kd = 3.9 X 10(-9) M) and low (Kd = 8.8 X 10(-8) M) affinity binding sites of [3H]PGE2 was demonstrated. The saturation values of [3H]PGE2 for high and low affinity binding sites were 0.13 pmol/mg protein and 1.22 pmol/mg protein, respectively. The digestion of the membranes with pronase, phospholipase C, D and neuraminidase led to a decrease of [3H]PGE2 binding but phospholipase A2 did not.

Alveolar Process↗
PubMed1983

Effect of pyridoxal 5'-phosphate on Ca2+-stimulated adenosine triphosphatase activity in microsomes of rat submandibular gland in vitro.

1. The Ca2+-ATPase activity in microsomes of rat submandibular gland was inhibited by pyridoxal 5'-phosphate in vitro. 2. The dissociation constant of the enzyme-pyridoxal 5'-phosphate complex was estimated to be 6.5 mM. 3. The inhibition of pyridoxal 5'-phosphate for both ATP and Ca2+ was competitive. 4. The order of inhibitory effectiveness of pyridoxal 5'-phosphate analogs was pyridoxal 5'-phosphate greater than pyridoxal HCl greater than pyridoxamine 5'-phosphate greater than pyridoxamine HCl. 5. The enzyme-pyridoxal 5'-phosphate complex was nonreducible with sodium borohydride.

Adenosine Triphosphate↗