PubMed Health⌕ Search

Biomedical subjects

A Misaki

Publications and source records attributed to A Misaki.

At least 55 records · Page 3Linked to original sources
PubMed1981

Studies on interrelation of structure and antitumor effects of polysaccharides: antitumor action of periodate-modified, branched (1 goes to 3)-beta-D-glucan of Auricularia auricula-judae, and other polysaccharides containing (1 goes to 3)-glycosidic linkages.

Antitumor activities of two (1 goes to 3)-beta-D-glucans, isolated from the fruiting body of Auricularia auricula-judae ("kikurage", an edible mushroom), and other branched polysaccharides containing a backbone chain of (1 goes to 2)-alpha-D-glucosidic or (1 goes to 3)-alpha-D-mannosidic linkage [and their corresponding (1 goes to 3)-D-glycans, derived by mild, Smith degradation] were compared. Among these polysaccharides, a water-soluble, branched (1 goes to 3)-beta-D-glucan (glucan I) of A. auricula-judae exhibited potent, inhibitory activity against implanted Sarcoma 180 solid tumor in mice. The alkali-insoluble, branched (1 goes to 3)-beta-D-glucan (glucan II), a major constituent of the fruiting body, showed essentially no inhibitory activity. When the latter glucan, having numerous branches attached, was modified by controlled, periodate oxidation, borohydride reduction, and mild, acid hydrolysis, the resulting, water-soluble, regraded glucan, having covalently linked polyhydroxy groups attached at O-6 of the (1 goes to 3)-linked D-glucosyl residues, exhibited potent antitumor activity. Further investigations using the glucan-polyalcohol indicated that the attachment of the polyhydroxy groups to the (1 goes to 3)-beta-D-glucan backbone may enhance the antitumor potency of the glucan. On the other hand, partial introduction of carboxymethyl groups into glucan II (d.s., 0.47--0.86), which altered the insolubility property, failed to enhance the antitumor activity. The interrelation between the antitumor activity and the structure of the branched (1 goes to 3)-beta-D-glucan is discussed, on the basis of methylation and 13C-n.m.r. studies of the periodate-modified glucans.

Animals↗
PubMed1981

Ultrasonic degradation of schizophyllan, an antitumor polysaccharide produced by Schizophyllum commune Fries.

Schizophyllan, a water-soluble beta-D-glucan elaborated by Schizophyllum commune Fries, was partially depolymerized by ultrasonic irradiation to a low-molecular-weight polysaccharide, designated "sonic-degraded schizophyllan". Both native and degraded polysaccharides exhibited essentially the same antitumor activities against Sarcoma-180 ascites. Both glucans are comprised solely of D-glucose residues and have a main chain of (1 leads to 3)-beta-D-glucopyranosyl residues, one out of three glucose residues being attached as single, (1 leads to 6)-beta-D-glucopyranosyl groups. Although both glucans have similar structural features, significant differences are observed in such physical properties as molecular weight and intrinsic viscosity. End-group analysis by using radioisotope-labeled glucans suggests that ultrasonic degradation occurs mainly by cleavage of glycosidic bonds of the main chain of schizophyllan. The molecular weights of the native and sonic-degraded schizophyllan were shown to be 75% of those of corresponding, original schizophyllan preparations, suggesting that there is no anomalous linkage sensitive to periodate oxidation, and ultrasonic irradiation may cause random hydrolysis of (1 leads to 3)-beta-D-glucosidic linkages in the main chain.

Animals↗
PubMed1980

Purification and characterization of Tora-bean (Phaseolus vulgaris) lectin.

A lectin purified from the Tora-bean (Phaseolus vulgaris) by affinity chromatography with Con-A Sepharose was shown to be a glycoprotein containing 7.8% neutral sugars (D-mannose, N-acetyl-D-glucosamine, L-fucose, and D-xylose, in a molar ratio of 9.6 : 2.0 : 0.6 : 0.7). Its molecular weight was 130,000, as estimated by exclusion gel chromatography, and SDS gel electrophoresis showed that it consists of four subunits of molecular weight 32,000. The lectin reacts with various glycoproteins, i.e., blood group substances, human parotid salivary glycoprotein, fetuin, and bovine submaxillary mucin. Divalent cations, such as Ca2+, Mn2+, and Mg2+, appear to stimulate its reactivity. Inhibition tests using the glycopeptide fragment from fetuin and some oligosaccharides, as well as the binding test with 14C-N-acetyl-lactosamine suggest that the sequence of D-galactose, N-acetyl-D-glucosamine, and D-mannose residues in the carbohydrate chain of fetuin is essential for binding.

Acetylglucosamine↗
PubMed1980

Interaction of parotid saliva basic glycoprotein with Streptococcus sanguis ATCC 10557.

It is postulated that an initial step in dental plaque formation is the adherence of oral bacteria to the salivary pellicle. Recently, we have found that a proline-rich and basic glycoprotein (MGP) from human parotid saliva, which is successfully purified by Concanavalin A-Sepharose affinity chromatography, binds to some oral streptococci such as S. mitis and S. sanguis. This paper deals with some inhibitors which affect the binding of the MGP to S. sanguis ATCC 10557. The assay for the binding ability of the radioactive MGP to the bacterial cells was performed by incubation of the reaction mixture containing 10 microgram of [3H]MGP (6000 dpm) and about 4.5 mg of bacterial cells (dry weight) in 0.5 ml of 0.05 M Tris-HCl buffer containing 0.05 M NaCl, pH 8.0 with a final volume of 0.51 ml. After 1 hour standing at 4 degrees C, the cells were washed five times with the same buffer. The resulting sediment was solubilized in 0.5 ml of NCS tissue solubilizer and the radioactivity was measured. The binding of the radioactive MGP to bacterial cells was specifically inhibited by galactose, lactose and N-acetyllactosamine. Applications of heat and trypsin on the cell surface, strikingly reduced the binding ability. These findings strongly suggested that a lectin-like substance may be present on the bacterial cell surface.

Adult↗
PubMed1980

[Enhancement of 67Ga tumor-to-blood ratios by chelating agent (author's transl)].

Chelating agent, such as CaEDTA, CaDTPA, D-penicillamine, DMSA, desferoxamine, NTA, cysteine ethyl ester, BAL, alpha-MPG, phthalein complexone, were tested as a possible contrast enhancing agent for tumor imaging with 67Ga-citrate. The intravenous administration of a chelating agent to Ehrlich's tumor bearing mice, one hour after the injection of 67Ga-citrate, accelerated the blood clearance with only a very slight change of activity in the target, increasing the tumor-to-blood ratio, and consequently achieving a better visualization. Among the tested chelating agents, D-penicillamine showed the highest target-to-nontarget ratio at a shorter time: a good tumor-to-blood ratio, performed after 24 hr with non-treated animals, was achieved in only 1-3 hr with post-treated animals. Thus, D-penicillamine hold a considerable promise as a contrast enhancing agent for future clinical use.

Animals↗
PubMed1979

Structure of the water-insoluble alpha-D-glucan of Streptococcus salivarius HHT.

Water-insoluble, non-adherent alpha-D-glucans have been obtained from Streptococcus salivarius HHT under two sets of conditions: from a growing culture, or synthesized enzymically by using a glucosyltransferase. In the former case, the glucan ([alpha]D + 197 degrees) was shown by methylation analysis to have a slightly branched structure containing a relatively high proportion (80%) of (1 leads to 3)-alpha-D-glucosidic linkages, together with small proportions of (1 leads to 6)- and (1 leads to 4)-alpha-D-glucosidic linkages. The enzymically synthesized glucan had a much less-branched structure, containing 88% of (1 leads to 3)-alpha-D-glucosidic linkages. Both glucans, on Smith degradation (sequential periodate oxidation, borohydride reduction, and mild acid hydrolysis), gave linear, (1 leads to 3)-alpha-D-glucosidic polysaccharides (yields, 82--90%) that constitute the backbone chains. The presence of small proportions of glycerol, erythritol, 1-O-alpha-D-glucosyl-D-glycerol, and also 2-O-alpha-D-glucosyl-D-erythritol in the products of Smith degradation suggests that the short side-chains are attached to the backbone chain by (1 leads to 4)-, (1 leads to 6)-, and (1 leads to 3)-alpha-D-glucosidic linkages.

Carbohydrate Sequence↗
PubMed1979

Preparative use of the analytical column of a sugar autoanalyzer for resolution of gluco-oligosaccharides of the same molecular weight.

A sugar autoanalyzer was used on a preparative scale to resolve a gluco-oligosaccharide mixture. In this way the components of the following mixtures were resolved: O-alpha-D-glucopyranosyl-(1-3)-O-[alpha-D-glucopyranosyl-(1-6)]-D-glucose (1), O-alpha-D-glucopyranosyl-(1-6)-O-alpha-D-glucopyranosyl-(1-3)-D-glucose (2) and O-alpha-D-glucopyranosyl-(1-3)-O-alpha-D-glucopyranosyl-(1-6)-D-glucose (3), O-alpha-D-glucopyranosyl-(1-3)-O-alpha-D-glucopyranosyl-(1-4)-D-glucose (4) and O-alpha-D-glucopyranosyl-(1-4)-O-alpha-D-glucopyranosyl-(1-3)-D-glucose (5), and O-alpha-D-glucopyranosyl-(1-2)-O-alpha-D-glucopyranosyl-(1-6)-O-alpha-D-glucopranosyl-(1-6)-O-alpha-D-glucopyranosyl-(1-6)-D-glucose (6) and O-alpha-D-glucopyranosyl-(1-3)--O-alpha-D-glucopyranosyl-(1-6)-O-alpha-D-glucopyranosyl-(1-6)-O-alpha-D-glucopyranosyl-(1-6)-D-glucose (7).

Autoanalysis↗
PubMed1977

Glycosyl moiety of the lima bean lectin.

Pronase digestion of the lima bean lectin (Phaseolus lunatus (alpha-D-GalNAc greater than alpha-D-Gal)) afforded a glycopeptide of molecular weight 1380. Amino acid and carbohydrate analysis showed the glycopeptide to contain fucose, mannose, glucosamine, and aspartic acid in the molar ratios, 0.8:4.4:1.9:1.0. Methylation analysis, Smith degradation, and sequential degradation by specific glycosidases permit the formulation of a tentative structure:.

Aspartic Acid↗
PubMed1977

Structural and immunochemical studies on D-arabino-D-mannans and D-mannans of Mycobacterium tuberculosis and other Mycobacterium species.

Serologically active D-arabino-D-mannas ([alpha]D, +82 degrees approximately 89 degrees; ratio of D-arabinose to D-mannose, 1-2:1) were isolated from the soluble fraction of disintegrated cells of M. tuberculosis, M. smegmatis, and several other Mycobacterium species. These arabinomannans had similar structures, consisting of alpha-(1 leads to 5)-linked D-arabinose residues and alpha-(1 leads to 6)-, and (1 leads to 2)-linked D-mannose residues. Methylation and enzymic degradation studies using Arthrobacter sp. alpha-D-mannosidase and M-2 enzyme (D-arabinan hydrolase) indicated that the arabinomannan of M. tuberculosis Aoyama B possesses short side chains built up from alpha-(1 leads to 2)-D-mannosidic linkages which are attached to an alpha-(1 leads to 6)-linked mannan back-bone chain. The alpha-(1 leads to 5)-linked D-arabinose residues located in the side chains were shown, by comparison of the immunochemical activities of the native and enzyme-degraded polysaccharides, to be the main immunodeterminants, as in the cell-wall arabinogalactan. There appeared to be variations in the ratio of arabinose and mannose residues, and also in the proportion of (1 leads to 2)-linked D-mannose units, depending on the individual strain; no (1 leads to 2)-mannosidic linkage was found in M. smegmatis arabinomannan. In addition to arabinomannan, a serologically inactive alpha-D-mannan ([alpha)D, +65 degrees approximately 68 degrees), whose structure may resemble that of the core mannan of the arabinomannan, was isolated as a copper hydroxide complex from the soluble fraction of disintegrated mycobacterial cells.

Arabinose↗
PubMed1976

Carbohydrate analysis of concanavalin A-reactive and concanavalin A-nonreactive mycobacterial polysaccharides.

Concanavalin A-nonreactive polysaccharide and 2 concanavalin A-reactive polysaccharides of differing concanavalin A affinities that had been purified from culture filtrates of Mycobacterium tuberculosis were subjected to carbohydrate analysis by gas and gas-liquid chromatography. Concanavalin A-nonreactive polysaccharide was found to be D-arabinogalactan, and the concanavalin A-reactive polysaccharide of highest affinity was found to be D-arabinomannan. The lower affinity concanavalin A-reactive polysaccharide was rich in arabinose and probably represented a mixture, with more than one polysaccharide present. Glucan was found to be a significant contaminant of all 3 polysaccharides.

Arabinose↗
PubMed1975

Structural differences in fructans elaborated by streptococcus mutans and Strep. salivarius.

D-Fructans synthesized from sucrose by cell-free systems of strains of Streptococcus mutans and Strep. salivarius have been shown by methylation and enzymatic studies to have different glycosidic linkages. The cold water-insoluble D-fructans from Strep. mutans strain BHT and JC-1 have inulin-type structures consisting beta-(2 leads to 1)-D-fructofuranosidic linkages, with average repeating units of 8 and 27 sugar residues, respectively, whereas the water-soluble fructan from Strep. salivarius strain HHT has a levan-type branched structure consisting beta-(2 leads to 6)-D-fructofuranosidic linkages with an average repeating unit of 9 sugar residues. The solubility properties of these fructants are discussed on the basis of the structural differences.

Fructans↗
PubMed1975

Isolation and purification of Flavobacterium alpha-1,3-glucanase-hydrolyzing, insoluble, sticky glucan of Streptococcus mutans.

Studies were made on the physical and chemical properties of polysaccharides synthesized by cell-free extracts of Streptococcus mutans, Streptococcus sanguis, and Streptococcus sp. and their susceptibilities to dextranases. Among the polysaccharides examined, insoluble glucans were rather resistant to available dextranase preparations, and the insoluble, sticky glucan produced by S. mutans OMZ 176, which could be important in formation of dental plaques, was the most resistant. By enrichment culture of soil specimens, using OMZ 176 glucans as the sole carbon source, an organism was isolated that produced colonies surrounded by a clear lytic zone on opaque agar plates containing the OMZ 176 glucan. The organism was identified as a strain of Flavobacterium and named the Ek-14 bacterium. EK-14 bacterium was grown in Trypticase soy broth, and an enzyme capable of hydrolyzing the OMZ 176 glucan was concentrated from the culture supernatant and purified by negative adsorption on a diethylaminoethyl-cellulose (DE-32) column and gradient elution chromatography with a carboxymethyl-cellulose (CM-32) column. The enzyme was a basic protein with an isoelectric point of pH 8.5 and molecular weight of 65,000. Its optimum pH was 6.3 and its optimal temperature was 42 C. The purified enzyme released 11% of the total glucose residues of the OMZ 176 glucan as reducing sugars and solubilized about half of the substrate glucan. The products were found to be isomaltose, nigerose, and nigerotriose, with some oligosaccharides. The purified enzyme split the alpha-1,3-glucan endolytically and was inactive toward glucans containing alpha-1,6, alpha-1,4, beta-1,3, beta-1,4, and/or beta-1,6 bonds as the main linkages.

Cell-Free System↗