Search PubMed⌕ Search

Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 811 records · Page 45Linked to original sources
PubMed1984

Aplysia myoglobins with an unusual amino acid sequence.

The complete amino acid sequence of the myoglobin from Aplysia juliana, a species distributed world-wide, has been determined and compared with the sequence of the myoglobin of Aplysia limacina, a Mediterranean species, and of Aplysia kurodai, a Japanese and Asian species. Unlike mammalian myoglobins, Aplysia myoglobins contain only a single histidine residue, lacking the distal one, the homology being 76% between A. juliana and A. limacina, 74% between A. juliana and A. kurodai, and 83% between A. limacina and A. kurodai. The hydropathy profiles of the Aplysia myoglobins are very similar, but completely different from that of sperm whale myoglobin, taken as the reference.

Amino Acid Sequence↗
PubMed1984

The amino acid sequence of sarcoplasmic calcium-binding protein obtained from sandworm, Perinereis vancaurica tetradentata.

The amino acid sequence of sarcoplasmic calcium-binding protein obtained from sandworm (Perinereis vancaurica tetradentata) has been determined. It is composed of 174 amino acid residues, its N-terminus is blocked by an acetyl group and the relative molecular mass is calculated to be 19556. From the results of amino acid sequence, it has three EF-hand-type calcium-binding sites. The positions of calcium-binding sites could be easily predicted by its hydropathy profile. Amino acid sequence homology between sarcoplasmic calcium-binding protein from different species is between 14-20%, thus it is not such a conservative protein.

Amino Acid Sequence↗
PubMed1984

Complete amino acid sequence of amelogenin in developing bovine enamel.

Pure amelogenin protein in developing bovine incisor enamel was isolated and its primary structure was investigated by sequencing the peptides obtained after clostripain and chymotrypsin digestions and CNBr degradation with an automated Edman sequencer. The enamel protein was found to be composed of 170 amino acid residues with one phosphate having a molecular weight of 19,350 and its complete amino acid sequence was elucidated. This protein has no sequence homology with any other tissue or secretory protein of known structure.

Amelogenin↗
PubMed1984

Relaxing effect of nicorandil (N-2-(hydroxyethyl)-nicotinamide nitrate), a new anti-angina agent, on the isolated vascular smooth muscle.

To define the mode of the vasorelaxing action of nicorandil as compared to nitroglycerin, the effects of the agent on the contractile response to various stimulations in rabbit aorta, cat coronary arteries and rabbit basilar arteries were evaluated. Nicorandil had a greater relaxing effect on the maximum response to norepinephrine (NE) than on the potassium (K+) response on all vascular smooth muscles used. In coronary and basilar arteries, however, the inhibitory action of nitroglycerin was not different on the response to both agonists. In coronary and basilar arteries the maximum inhibition of the NE response by nicorandil was greater than that by nitroglycerin. Nicorandil (10(-5) M) but not phentolamine (10(-5) M) inhibited the PGF2 alpha-induced contraction of the aorta. Either nicorandil or nitroglycerin suppressed the response of the aorta to the transmural stimulation. In a Ca2+-free medium containing K+ (40 mM), nicorandil decreased the response to excess Ca2+ in all preparations whereas, nifedipine (10(-6)-10(-5) M) abolished it. Nitroglycerin, however, had no effect on the Ca2+-induced contraction on basilar arteries. In a Ca2+-free medium, the residual NE-induced contraction was inhibited by nicorandil or nitroglycerin but not by nifedipine . The combined treatment with nicorandil and nitroglycerin caused a stronger suppression of residual NE response that that of a single treatment with either agent suggesting the different site of action for the two agents. These results suggest that the mode of vasorelaxing action of nicorandil may be due to the alteration (inhibition) of Ca2+ kinetics in the cell.

Animals↗
PubMed1984

GENAS: a database system for nucleic acid sequence analysis.

A database system, named GENAS (GENe Analyzing System), for computer analysis of sequence was constructed using Adbis which is a relational database management system (1). GENAS enables us to retrieve any sequence data from EMBL nucleotide sequence data library (2) and readily to analyze them (if necessary, together with private data) by various application programs in a interactive manner. Analysis of structure of replication origin of replicons was demonstrated using this system.

Base Sequence↗
PubMed1984

Systematic purification of free and matrix-bound phosphophoryns of bovine dentin: presence of matrix-bound phosphophoryn as a distinct molecular entity.

Free and matrix-bound phosphophoryns, both highly phosphorylated proteins in dentin, were prepared from EDTA extract and CNBr-digests of bovine dentin. The two components were purified by DEAE-cellulose, SP-Sephadex, and gel filtration chromatography. The matrix-bound component was eluted as a distinct peak from the free component in the above chromatographic systems. Amino acid composition of the purified matrix-bound component indicated that this component consisted of phosphophoryn and collagen in the ratio of 2:3 based on the number of the residues. The matrix-bound component could not be reconstituted by mixing phosphophoryn with collagen CNBr peptides. Artificial crosslink products of free phosphophoryn and collagen CNBr-peptides by the carbodiimide method showed similar properties to the physiological matrix-bound phosphophoryn. The bond between phosphophoryn and collagen of the matrix-bound component is assumed to be a covalent crosslink.

Amino Acids↗
PubMed1984

The alpha 1(I) and alpha 2(I) chains of collagen separate in sodium dodecyl sulfate-polyacrylamide gel electrophoresis due to differences in sodium dodecyl sulfate binding capacities.

The alpha 1(I) and alpha 2(I) chains of rat tail collagen, indistinguishable with respect to their chain lengths, are well separated in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS). In the present study, the results demonstrated: 1) the alpha 2 chain maximally binds SDS in an amount of 1.6 g/g which is significantly larger than 1.4 g/g found for the alpha 1 chain; 2) the alpha 2 chain acquires electrophoretic mobility in a free solution 14% higher than that of the alpha 1 chain as the result of the larger amount of SDS bound; 3) although both of the chains have virtually the same hydrodynamically effective size, the above difference in mobility persists in a gel, and brings about the separation in a high resolution. It was also found that the alpha 2 chain binds appreciable amounts of SDS in the initial phase of the binding where the alpha 1 chain hardly binds SDS.

Animals↗
PubMed1984

The influence of dietary isomeric and saturated fatty acids on atherosclerosis and eicosanoid synthesis in swine.

Weanling swine were fed for 6 months high fat diets containing as fat source, a high oleic acid safflower oil, lard, or a partially hydrogenated soybean oil blended with soybean oil. The extent of atherosclerosis in left coronary arteries and the ability of vascular components to synthesize eicosanoids important for blood clotting were determined. There was no significant difference (p greater than 0.05) in the extent of atherosclerosis or the synthesis of thromboxane A2. Significant effects were observed on serum cholesterol, which was elevated in the lard fed group, serum triacylglycerol, which was highest in the safflower oil group, and prostacyclin synthesis, which was depressed in both the lard and hydrogenated soybean oil diets compared to the safflower oil diet. No unique effect on the development of heart disease appears to be attributable to hydrogenated fats. The hydrogenated fat was similar to lard in decreasing prostacyclin synthesis, suggesting that the saturation of dietary fatty acids may be a contributory factor in the development of heart disease, through its effect on thrombotic processes.

Adipose Tissue↗
PubMed1984

Amino acid sequence of Japanese horseshoe crab (Tachypleus tridentatus) coagulogen B chain: completion of the coagulogen sequence.

The complete amino acid sequence of the B chain derived from Tachypleus tridentatus coagulogen was determined. It consisted of a total of 129 amino acid residues with a NH2-terminal glycine and COOH-terminal phenylalanine. Sequence studies of the whole B chain and the fragments obtained from the digests with trypsin, alpha-chymotrypsin, thermolysin and Staphylococcal protease V8 showed the following sequence: (sequence; see text) These structural studies of the B chain and the previously established amino acid sequences of the A chain and peptide C derived from T. tridentatus coagulogen, now make it possible to complete the whole sequence of coagulogen consisting of 175 amino acid residues with the molecular weight of 19,723.

Amino Acid Sequence↗
PubMed1984

Molecular weight and related properties of lily amylose determined by monitoring of elution from TSK-GEL PW high performance gel chromatography columns by the low-angle laser light scattering technique and precision differential refractometry.

Amylose was fractionated according to its molecular weight by high performance gel chromatography using columns of a TSK-GEL PW series. Elution from the columns was monitored with a low-angle laser light scattering photometer and a precision differential refractometer. The following results were obtained indicating that the procedure is highly efficient for characterizing an amylose preparation with respect to its molecular weight: 1) the weight-average molecular weight of lily amylose used as a test material was determined to be 786,000 +/- 26,000 (n = 7); 2) the molecular weight distribution curve of the amylose was worked out from the chromatographic data; and 3) based on the concept of the universal calibration curve, the Mark-Houwink-Sakurada equation of the amylose was presumed to be [eta] = 2.27 X 10(-4)M0.62 (dl/g). The technique saves time and sample significantly compared with the conventional ones, and consequently enables the characterization of amylose in aqueous solvents without either the degradation or association peculiar to the amylose molecule.

Amylose↗
PubMed1984

Amino acid sequence of alpha chain of sarcoplasmic calcium binding protein obtained from shrimp tail muscle.

The isotypes of sarcoplasmic Ca2+ binding protein (SCP) were purified from shrimp tail muscle. SCP exists in a dimeric form. One sample of shrimp contained only alpha A chain, whereas another contained alpha B and beta chains, and a heterodimer of alpha B beta which was not analyzed precisely. The amino acid sequences of the two alpha chains were determined. The two alpha chains are composed of 190 and 192 amino acid residues, respectively. The sequences of the two alpha chains differed in only four amino acids out of 192 residues. The sequences indicate that the alpha chain has three Ca2+-binding sites which are common to EF-hand type Ca2+-binding protein. In the absence of added Ca2+ and Mg2+, the amounts of bound Ca2+ in alpha A, alpha B, and beta chains were 3.0, 3.3, and 2.4 mol/22,000 g protein, respectively. Thus, it is suggested that all three isotypes of shrimp SCP have three Ca2+-binding sites which have high affinity to Ca2+. The sequence homology of shrimp SCP with other EF-hand type Ca2+-binding proteins is very low. The protein having the greatest homology with this SCP was cod parvalbumin; the sequence homology is 18%.

Amino Acid Sequence↗
PubMed1984

Amino acid sequence of the beta chain of sarcoplasmic calcium binding protein (SCP) obtained from shrimp tail muscle.

The amino acid sequence of the beta chain of shrimp SCP has been determined. It is composed of 192 amino acid residues and is acetylated at the N-terminus. The molecular weight was determined to be 21,960. The sequence difference with the aB chain of the same shrimp, of which the sequence was determined previously (J Biochem. (1984) 95, 1603-1615), is 19% (37 non-identical residues out of 192 residues). The shrimp SCPs have three EF-hand type Ca2+ binding sites, however, from comparison with the amino acid sequences of SCPs of scallop (Takagi et al., Biochim. Biophys. Acta in press) and of sandworm (Kobayashi et al., manuscript in preparation), it is reasonable to think that SCP originally had four Ca2+ binding sites, and in the case of shrimp SCPs, one of them (site IV) may have lost the affinity to Ca2+ on amino acid replacements during evolution.

Amino Acid Sequence↗
PubMed1984

Ultrastructure of newly formed vessels in thrombi. Endothelium formation in human umbilical artery.

Thrombi with newly formed vessels in thirteen human umbilical arteries were studied. Red blood cells formed masses which were covered by fibrin within twelve hours after birth. By the second day, the intima including endothelial cells was denuded. In the junctional area between the thrombi and the original intima on the sixth day, red blood cells were surrounded by endothelial-like cells, which displayed junctional complexes and did not show any connection with intact endothelial cells. These cells also exhibited filaments with fusiform densities, suggesting a probable origin from vascular smooth muscle cells. Examination of older specimens indicated that these were precursor structures of functional capillaries found in mature thrombi.

Age Factors↗
PubMed1984

Ultrastructure of aging human umbilical artery and vein.

Qualitative and quantitative changes in the human umbilical artery and vein were observed in 15 human specimens at different stages of development. Features such as intimal thickening and cellular lipid accumulation were found in umbilical vasculature. Cellular origin and quantification of lipid-containing cells were determined by electron microscopy. Within 1 month after birth, lipid-containing cells originating from macrophages were observed in the umbilical artery, while those originating from smooth muscle cells were observed in both the umbilical artery and vein. Lipid droplet formation appeared to be independent and different in macrophages and smooth muscle cells; the former cells were stimulated to produce lipid droplets primarily by plasma insudation and the latter cells primarily by hypoxia. These findings indicate that ultrastructural changes observed in closing umbilical vasculature may closely parallel and serve as a model for atherosclerotic changes which occur in mature vessels.

Aging↗
PubMed1984

Biochemical studies on the collagen of the palmar aponeurosis affected with Dupuytren's disease.

The palmar aponeurosis of patients affected with Dupuytren's disease was examined for collagen characteristics with regard to extractability, polymorphism, and posttranslational modifications, and the results were compared with those from normal subjects. The increased proportion of type III collagen relative to type I collagen in the affected tissue confirmed the previous findings in this disease. A slight but significant increase in a ratio of glucosylgalactosylhydroxylysine to galactosylhydroxylysine in the Dupuytren's tissue may be interpreted by the increase in the content of type III collagen. The affected tissue contained increased amounts of dihydroxylysinonorleucine as the reducible cross-link of collagen. These data support the view that Dupuytren's tissue contains collagen resembling that in granulation and embryonic tissues. Pyridinoline was shown to occur in normal and affected aponeurosis. No change in its content suggests that this cross-link is not involved in the pathogenesis of contracture in this disease.

Amino Acids↗