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Biomedical subjects

K Takeo

Publications and source records attributed to K Takeo.

At least 109 records · Page 6Linked to original sources
PubMed1984

Freeze-fracture observations of the cell walls and peribacillary substances of various mycobacteria.

Ultrastructure of the cell wall and peribacillary substances of various mycobacteria (32 strains of 18 species) grown in vitro was studied by a freeze-fracture technique. Peribacillary substances differed in shape among species and even among strains of the same species, and were classified into five types: (1) amorphous substances; (2) multi-layered sheaths with no filamentous units; (3) structures composed of filaments of 2-4 nm diameter, which were further classified into three subtypes according to the arrangement of the filaments; (4) helical fibres; and (5) single fibres, or networks of fibrous structures, with no visible substructures. No strains revealed peribacillary structures resembling those of uncultivable Mycobacterium leprae. These results have implications for the mechanism of freeze-fracturing in mycobacterial walls.

Cell Wall↗
PubMed1984

Pharmacological properties of a new anti-inflammatory compound, alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolacto ne (KME-4), and its inhibitory effects on prostaglandin synthetase and 5-lipoxygenase.

The pharmacological effects of a new anti-inflammatory compound, alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), and its inhibitory effects on arachidonate prostaglandin synthetase and 5-lipoxygenase activities were examined. KME-4 showed anti-inflammatory activity. It was less active than indomethacin, but more active than naproxen and ibuprofen in carrageenin-induced paw edema in rats; and it was less active than indomethacin, equipotent as naproxen, but more active than ibuprofen in granuloma formation in rats. The ulcerogenic activity of KME-4 was weaker than indomethacin and naproxen, but stronger than ibuprofen in starved rats. The ratio of UD50 stomach to ED30 carrageenin edema or to ED25 granuloma for KME-4 showed higher values than those of the reference drugs. KME-4 showed antipyretic activity in yeast-induced fever in rats. It also inhibited platelet aggregation induced by arachidonic acid and protected rabbits from arachidonic acid-induced death. Furthermore, KME-4 was found to be equipotent in inhibiting both prostaglandin synthetase and 5-lipoxygenase activities of rat basophilic leukemia cells, unlike indomethacin, naproxen and ibuprofen. It also inhibited the prostaglandin synthetase activity of bovine seminal vesicle. The present findings indicate that KME-4 may be a new type of anti-inflammatory drug with dual prostaglandin synthetase and 5-lipoxygenase inhibition.

4-Butyrolactone↗
PubMed1983

An exploration of the binding site of aldolase using alkanediol monoglycolate bisphosphoric esters.

Alkanediol monoglycolate bisphosphoric esters (P-O-CH2-CO-O-(CH2)n-O-P), which are analogues of the aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13) substrate fructose 1,6-bisphosphate, were synthesized and used for probing its active site. The Ki value was lowest when the maximum distance between the phosphorus atoms of the bisphosphate was brought close to that of fructose 1,6-bisphosphate. The binding constants estimated from difference spectra correlate well with Ki values for the substrate analogues. Propanediol monoglycolate bisphosphoric ester protected aldolase from inactivation by 1,2-cyclohexanedione, which preferentially attacks arginine-55. However, propanol phosphate had little protective effect. The synthesized phosphate compounds protected the enzyme against inactivation by trypsin, and also against spontaneous denaturation. These results suggest that the synthesized phosphate compounds bind to aldolase at the active site, which tends to keep the distance constant between the two phosphate-binding sites for the open-chain form of fructose 1,6-bisphosphate, and stabilize the natural conformation of the enzyme. Both arginine-55 and lysine-146 are shown to participate in the phosphate-binding site for the C-1-phosphate of fructose 1,6-bisphosphate.

Animals↗
PubMed1983

Differences of asymmetrical division between the pseudomycelial and yeast forms of Candida albicans and their effect on multiplication.

Unlike asymmetrical division of budding yeast, the daughter cell in the pseudomycelial form of Candida albicans at division was nearly equal in size to the mother cell, it had a larger amount of protein, RNA and active protoplasm (cell size minus vacuolar volume) than the mother cell, and it budded earlier than the mother cell. Results presented here suggest that the cell size control over bud initiation found in budding yeasts is also applicable to the pseudomycelial cells of C. albicans if vacuolar volume is omitted from cell size.

Candida albicans↗
PubMed1980

Study of the interaction between NADP-dependent dehydrogenase and immobilized adenosine 2'-monophosphate by means of affinity electrophoresis.

A water-soluble 8-substituted adenosine 2'-monophosphate-polyacrylamide (8-sub-2'-AMP-PA) was prepared as a new affinity ligand for the determination of the dissociation constants of the interactions between immobilized 8-sub-2'-AMP and NADP-dependent dehydrogenases (NADP-dependent DH), NAD-dependent dehydrogenases (NAD-dependent DH) and phosphorylase by means of affinity electrophoresis. From the dissociation constants, it was found that NADP-dependent DH had a much stronger affinity to immobilized 8-sub-2'-AMP than did NAD-dependent DH and phosphorylase. On the other hand, NADP-dependent DH had a much weaker affinity to immobilized 8-sub-5'-AMP than did NAD-dependent DH. The effects of NADP+ and NAD+ on the interaction between immobilized 8-sub-2'-AMP and NADP-dependent DH were also investigated by means of affinity electrophoresis. NADP+ inhibited the interaction specifically, but NAD+ did not inhibit the interaction. These results indicate that 8-sub-2'-AMP binds to the coenzyme binding site of NADP-dependent DH, while other compounds, such as 8-sub-5'-AMP and NAD+, do not bind to NADP-depenndent DH. Such a difference suggests that the phosphate group at position 2' in 2'-AMP and NADP+ is important for the binding at the coenzyme binding site of NADP-dependent DH.

Adenosine Monophosphate↗
PubMed1980

Study of the interaction between L-lactate dehydrogenase isoenzymes and immobilized 8-substituted adenosine 5'-monophosphate by means of affinity electrophoresis.

A water-soluble 8-substituted adenosine 5'-monophosphate-polyacrylamide (8-sub-5'-AMP-PA) was prepared as an affinity ligand for the affinity electrophoresis of L-lactate dehydrogenase (LDH). According to the principles of affinity electrophoresis, the dissociation constants of the interaction between immobilized 8-sub-5'-AMP and rabbit LDH isoenzymes [LDH-1(H4), LDH-2(H3M), LDH-3(H2M2), LDH-4(HM3) and LDH-5(M4)], beef LDH-1(H4) and LDH-5(M4) and pig LDH-1(H4) were calculated. Both rabbit and beef LDH-5 (muscle-type isoenzymes) had approximately a 35-fold stronger affinity to immobilized 8-sub-5'-AMP than has their LDH-1 (heart-type isoenzymes). The effects of free nucleotides on the interaction between immobilized 8-sub-5'-AMP and LDH isoenzymes were also investigated by affinity electrophoresis. NAD+ has a stronger affinity to LDH-5(M4) than had 5'-AMP and 5'-IMP, while NMN, adenosine and fructose 6-phosphate had no affinity.

Adenosine Monophosphate↗
PubMed1979

Study of the interaction between phosphorylase and hydrophobic groups by means of affinity electrophoresis.

A homologous series of water-soluble alkyl-dextrans varying in the length of their hydrocarbon side-chain [-NH-(CH2)n-CH3; n = 1-5] were synthesized. When alkyl-dextrans were entrapped in polyacrylamide gel, the electrophoretic mobility of phosphorylase was retarded by hydrophobic interaction between phosphorylase and the immobilized alkyl groups. The dissociation constants of rabbit brain phosphorylase, rabbit skeletal muscle phosphorylase a and b and potato glycogen and starch phosphorylases were calculated from the extent of the retardation of mobility as a function of the concentration of the alkyl groups. As the length of the hydrocarbon side-chains of alkyl groups increased, the affinity of the phosphorylases for the alkyl groups increased. The introduction of a hydroxyl or an amino group at the terminal position of the hydrocarbon side-chain diminished the affinity.

Animals↗
PubMed1979

Binding constants of NZB myeloma antidextrans for dextrans and isomaltose oligosaccharides determined by affinity electrophoresis.

Association constants of dextrans (Ka) and oligosaccharides (Kia) from NZB myeloma antidextrans (PC3858 and PC3936) were studied by affinity electrophoresis. With linear dextrans or with those with a low degree of branching, Ka ranged from 2.7 X 10(3) to 5.4 X 10(4) ml/g for PC3858 and from 1.3 X 10(4) to 2.6 X 10(5) ml/g for PC3936. Completely linear alpha-(1 leads to 6)-linked dextrans, LD7 and D3, showed relatively high affinities for the two NZB antidextrans. With oligosaccharides, the Kia value increased as the number oa alpha-(1 leads to 6)-linked glycosyl residues increased. Isomaltoheptaose (IM7) showed the highest Kia (1.9 X 10(4) M-1 for PC3858 and 1.63 X 10(4) M-1 for PC3936), whereas isomaltose (IM2) had the lowest Kia (2.36 X 10(2)M-1 for PC3858 and 1.32 X 10(2)M-1 for PC3936). Pullulan and glycogen showed very weak affinity for PC3936, but they did not react at all with PC3858. These findings indicate that NZB myeloma antidextrans, PC3858 and PC3936, are specific for internal chains of alpha-(1 leads to 6)-linked dextrans. Data on the precision with which Ka and Kia can be determined are presented.

Animals↗
PubMed1978

Hydrolysis of aryl beta-maltotriosides by sweet potato beta-amylase and soybean beta-amylase.

Sweet potato beta-amylase [EC 3.2.1.2, alpha 1,4-D-glucan maltohydrolase]-catalyzed hydrolyses of aryl beta-maltotriosides with substituents, NO2-, Cl-, and Br- at the o-, m-, and p-positions in the phenyl ring were studied at pH 4.8 and 25 degrees C. The hydrolyses of a few of the maltotriosides by soybean beta-amylase [EC 3.2.1.2, alpha-1,4-D-glucan maltohydrolase] were also studied at pH 5.4 and 25 degrees C. It was found that the aryl beta-maltotriosides were preferentially hydrolyzed into maltose and aryl beta-D-glucosides by both beta-amylases. The Michaelis constant Km and the molecular activity ko were determined for the hydrolyses of these maltotriosides and compared with those of maltotriose and maltotetraose. Aryl beta-maltotriosides were more rapidly hydrolyzed than maltotriose by a factor of 30--80, and more slowly hydrolyzed than maltotetraose by a factor of 10--30, depending on the kinds of substituents. The rapid hydrolysis of aryl beta-maltotrioside as compared with maltotriose may be due to the interaction of an aryl group with the subsite of beta-amylase. This is in contrast with glucoamylase [EC 3.2.1.3, alpha-1,4-D-glucan glucohydrolase] of Rhizopus niveus-catalyzed hydrolysis of phenyl beta-maltoside, whose phenyl group does not interact so much with the subsite of the enzyme.

Amylases↗
PubMed1976

Existence of a surface configuration on the aerial spore and aerial mycelium of Micropolyspora.

We report the existence of a surface configuration in a true spore-forming genus having cell wall constituents of type IV. Micropolyspora angiospora, M. caesia and M. faeni freeze-fractured along the wall surface and only had a surface configuration on their aerial mycelium and aerial spores, with none on the substrate mycelium and substrate spore. The surface configuration of Micropolyspora was distinctly more complicated than that of Nocardia. The aerial spores of M. angiospora were characteristic in that they possessed ridges, two kinds of surface configurations (i.e. rodlets and fibres), and a complex pattern on the surface. Some rodlets of this organism were formed of a two-stranded helix, each strand having a diameter similar to that of a fibre.

Actinomycetales↗
PubMed1976

Plasma membrane ultrastructural differences between the exponential and stationary phases of Saccharomyces cerevisiae as revealed by freeze-etching.

Ultrastructural changes in the plasma membrane of Saccharomyces cerevisiae during the exponential and stationary growth phases were studied by freeze-etching. In the exponential phase, plasma membrane-intercalated particles were distributed randomly. In the stationary phase, several areas of the plasma membrane showed a hexagonal arrangement of particles; these areas appeared to increase with the age of the culture. The polarity of the particles also changed partially: the E-face of the plasma membrane was only sparsely embedded with particles in exponential phase cells, but relatively densely embedded in stationary phase cells. Invaginations of the plasma membrane on the P-face were devoid of particles during both growth phases. Invaginations of the E-face were sparsely embedded with particles in exponential phase cells, but densely embedded with particles in stationary phase cells.

Cell Membrane↗