Biomedical subjects

K Takumi

Publications and source records attributed to K Takumi.

48 records · Page 3Linked to original sources

PubMed1980

Isolation of nontoxigenic variants associated with enhanced sporulation and alteration in the cell wall from Clostridium botulinum type a 190L by treatment with detergents.

Nontoxigenic variants were isolated from Clostridium botulinum type A strain 190L after treatment with detergents such as deoxycholate, sodium dodecyl sulfate, Tween 80 and Brij-58. Deoxycholate was most effective for obtaining the variants. The variants exhibited a markedly increased frequency of sporulation compared with the oligosporogenic parent strain. The cell wall of the parent strain was composed of an outer layer and an inner layer, whereas that of the variants lost the outer layer. After treatment with mitomycin C the parent strain was subjected to lysis and produced bacteriophages with a hexagonal head and a contractible tail, while the nontoxigenic variants did not yield bacteriophages or phage-like structures. There appears to be a close relationship among the toxigenic and sporogenic properties, formation of the outer cell wall layer and lysogeny.

Botulinum Toxins↗

PubMed1980

Ultrastructure of a hexagonal array in exosporium of a highly sporogenic mutant of Clostridium botulinum type A revealed by electron microscopy using optical diffraction and filtration.

The ultrastructure of a hexagonal array in the exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A strain 190L was studied by electron microscopy of negatively stained exosporium fragments using optical diffraction and filtration. The exosporium was composed of three or more lamellae showing and equilateral, hexagonal periodicity. Images of the single exosporium layer from which the noise had been filtered optically revealed that the hexagonally arranged, morphological unit of the exosporium was composed of three globular subunits about 2.1 nm in diameter which were arranged at the vertices of an equilateral triangle with sides of about 2.4 nm. The morphological units were arranged with a spacing of about 4.5 nm. the adjacent globular subunits appeared to be interconnected by delicate linkers.

Clostridium botulinum↗

PubMed1979

Isolation and partial characterization of exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A.

Homogeneous fragments of exosporium were isolated and purified from mature spores of a highly sporogenic mutant derived from Clostridium botulinum type A strain 190L. The exosporium was composed of three lamellae and showed a hexagonal array when negatively stained. The hexagonal array of isolated exosporium was resistant to sodium dodecyl sulfate, urea, dithiothreitol, and proteolytic enzymes such as trypsin, pronase, and nagarse, except for pepsin. The hexagonal array was partially disintegrated with 5 M guanidine-HCl and almost completely disrupted with 8 M urea in combination with 1% mercaptoethanol under alkaline conditions. The purified exosporium fraction was composed mainly of protein (69.1%) and lipids (13.8%). A small amount of amino sugars (2.5%) was present, but neutral sugars could not be detected. The exosporium protein had a predominantly acidic amino acid composition accompanied by low levels of cystine, methionine, and histidine.

Amino Acids↗

PubMed1976

Quantitative chemical analyses and antigenic properties of peptidoglycans from Clostridium botulinum and other clostridia.

The cell wall peptodoglycans were isolated from Clostridium botulinum and some other species of the genus Clostridium by hot formamide extraction and their quantitative chemical composition and antigenic properties were determined. The petidoglycan of C. botulinum type E was found to be a diaminopimelic acid (DAP)-containing type composed of glucosamine, muramic acid, glutamic acid, alanine and DAP in the molar ratio of 0.76:0.78:1.00:1.88:0.81. All other types of C. botulinum and Clostridium sporogenes also belonged to the same peptidoglycan type. The peptidoglycans of Clostridium bifermentans and Clostridium histoloyticum contained DAP but they differed from those of C. botulinum in the molar ratio of alanine to glutamic acid. The peptidoglycan of Clostridium perfringens was composed of glutamic acid, alanine, DAP and glycine in the molar ratio of 1.00:1.64:0.94:0.90. On the other hand, the peptidoglycan of Clostridium septicum was found to contain lysine instead of DAP and the molar ratio was 1.00:1.41:0.96 for glutamic acid, alanine and lysine. In spite of the difference in amino acid composition of peptidoglycans among the clostridia, the quantitative precipitin test demonstrated that antiserum against C. botulinum type E peptidoglycan cross-reacted with the peptidoglycans from other clostridia as well as various types of C. botulinum.

Alanine↗

PubMed1975

Immunochemical characterization of cell wall protein antigen purified from the cell wall autolysate of Clostridium botulinum type A.

The cell wall protein antigen was solubilized from the isolated cell walls of Clostridium botulinum type A by autolysis and purified by diethylaminoethyl-cellulose column chromatography followed by gel filtration on Sephadex G-150. The two fractions showed a high degree of the serological activity and produced a main fused precipitin line in immunodiffusion tests against the homologous antiserum. The fact that antigenic fractions contained various kinds of amino acids but no detectable amounts of amino sugars or carbohydrates suggests that the antigens were principally composed of proteins. The protein antigen possessed multiple antigenic components in immunoelectrophoresis. As serological activity, the antigen was heat-stable and resistant to tryptic digestion but sensitive to the actions of pronase, nagarse or pepsin. The protein antigen appeared to be responsible for the common antigenicity among the proteolytic strains of C. botulinum.

Antigens, Bacterial↗

PubMed1975