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Biomedical subjects

T Kumazaki

Publications and source records attributed to T Kumazaki.

At least 253 records · Page 14Linked to original sources
PubMed1982

Nucleotide sequences of 5S rRNAs from four jellyfishes.

The nucleotide sequences of 5S rRNAs from four jellyfishes, Spirocodon saltatrix, Nemopsis dofleini, Aurelia aurita and Chrysaora quinquecirrha have been determined. The sequences are highly similar to each other. A fairly high similarity was also found between these jellyfishes and a sea anemone, Anthopleura japonica.

Animals↗
PubMed1982

The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and Caenorhabditis elegans.

The nucleotide sequences of 5S rRNAs from a rotifer, Brachionus plicatilis, and two nematodes, Rhabditis tokai and Caenorhabditis elegans have been determined. The rotifer has two 5S rRNA species that are composed of 120 and 121 nucleotides, respectively. The sequences of these two 5S rRNAs are the same except that the latter has an additional base at its 3'-terminus. The 5S rRNAs from the two nematode species are both 119 nucleotides long. The sequence similarity percents are 79% (Brachionus/Rhabditis), 80% (Brachionus/Caenorhabditis), and 95% (Rhabditis/Caenorhabditis) among these three species. Brachionus revealed the highest similarity to Lingula (89%), but not to the nematodes (79%).

Animals↗
PubMed1982

The nucleotide sequences of 5S rRNAs from three ciliated protozoa.

The nucleotide sequences of 5S rRNAs from three ciliated protozoa, Paramecium tetraurelia, Tetrahymena thermophila and Blepharisma japonicum have been determined. All of them are 120 nucleotides long and the sequence of probable tRNA binding site of position 41-44 is GAAC which is characteristic of the plant 5S rRNAs. The sequence similarity percents are 87% (Paramecium/Tetrahymena), 86% (Paramecium/Blepharisma) and 79% (Tetrahymena/Blepharisma), suggesting a close relationship of these three ciliates.

Animals↗
PubMed1982

A simple photometric method for determination of the activity of pyrocin R1.

A simple photometric method for rapid and accurate determination of the activity of pyocin R1, a bacteriocin produced by Pseudomonas aeruginosa strain P15, has been developed. This method is based on the turbidity-decrease observed when the bacteriocin is added to a suspension of sensitive bacteria P. aeruginosa strain P11. Optimum conditions for the turbidity-decreasing activity of pyocin R1 are in 0.01 M Tris-HCl buffer containing 0.2 M NaCl (pH 7.5) at 37 degrees C. A good correlation was found between the dose of pyocin R1 and the rate of the turbidity-decrease (with a correlation coefficient of more than 0.98). The amount of pyocin R1 required for this assay is nearly the same as that used for the conventional colony-counts method. The assay for one sample takes less than 3 min, whereas an overnight wait is necessary for the conventional method. This method is shown to be very suitable for following the time course of activity change observed when pyocin R1 is treated with various chemicals, including receptor substances obtained from sensitive cells. The turbidity-decrease assay was also found to be applicable to the determination of activities of other R-type pyocins.

Bacteriocins↗
PubMed1982

Isolation and characterization of pyocin R1 fibers.

By a mild alkaline treatment, pyocin R1 was disassembled into its structural parts, a contracted sheath (and its fragments), a core, and fibers. An alkaline sucrose density gradient centrifugation after this treatment was effective in obtaining fiber-density fractions. The pooled fractions were treated with IgGs against isolated sheaths and isolated cores, simultaneously, and then chromatographed on DEAE-Sepharose CL-6B. The final preparation of fibers purified in this way was confirmed to be homogeneous by electron microscopic observation and an immuno-precipitation reaction. The isolated fiber was found to consist of two major subunit proteins, No. 2 and No. 9, with molecular weights of 71,000 and 31,000, respectively. The fiber exhibited the ability to be adsorbed on sensitive bacterial cells (pseudomonas aeruginosa P14), and to protect against the inactivation of pyocin R1 by a lipopolysaccharide preparation from the bacteria.

Amino Acids↗
PubMed1982

Comparative study on fibers isolated from four R-type pyocins, phage-tail-like bacteriocins of Pseudomonas aeruginosa.

Five R-type pyocins have been reported which are almost identical with one another in their morphology and subunit composition, though distinct in receptor-binding specificity. We isolated fibers from pyocin R2, R3, and R4 by essentially the same procedure as used in our previous isolation of pyocin R1 fiber with unimpaired receptor-binding ability. All the isolated fibers including R1 fiber were indistinguishable from one another, in terms of electron microscopic observation and subunit composition analysis by SDS gel electrophoresis. They consisted mainly of Subunit No. 2 (Mw 71,000) and No. 9 (31,000) proteins. Although Subunit No. 9 protein in every fiber was susceptible to trypsin and afforded a fragment with the same molecular weight (about 19,000) detectable in the SDS gel, Subunit No. 2 protein was cleaved with trypsin only after the fiber had been treated with an organomercurial, 4-(p-sulfophenylazo)-2-mercuriphenol. The cleavage of Subunit No. 2 protein proceeded to give several fragments with molecular weights ranging from 64,000 to 34,000, and the fragmentation patterns were electrophoretically distinct at least among R1 fiber, R3 fiber, and others (R2 and R4 fibers). The results indicate that Subunit No. 2 proteins of these fibers are different from one another in the structure surrounding trypsin-susceptible peptide bonds. Immunological investigations with anti-R1 fiber antibodies provided some additional information on the difference among R-type pyocins at the fiber level.

Amino Acids↗
PubMed1982

Specific cleavage at fibers of a bacteriophage-tail-like bacteriocin, pyocin R1, by successive treatment with organomercurial compounds and trypsin.

When pretreated with the organomercurial compound that reversibly blocks the adhesion of pyocin R1 to sensitive cells, this bacteriocin became susceptible to trypsin. Trypsinization resulted in the exclusive fragmentation of subunit protein no. 2 among 20 different subunit components and the disappearance of distal knobs from the fibers as well as in irreversible inactivation.

Bacteriocins↗
PubMed1979

Characterization of active derivatives produced by acetamidination and selective autolysis of bovine trypsin.

A commercial preparation of bovine trypsin was treated with methyl acetimidate-HCl, and most of the lysine residues were converted to trypsin-resistant residues retaining their cationic charges. The modified preparation was then fractionated by ion-exchange chromatography on SE-Sephadex C-50 into two active components, amidinated alpha- and amidinated beta-trypsins. The latter component (Am-beta-trypsin), which consisted of a single polypeptide chain, was allowed to autolyze at pH 7.8, 25 degrees C for 3.5 h and a new active component named Am-delta-trypsin was isolated from the autolysate. Several lines of experimental evidence indicated that Am-delta-trypsin was derived by primary cleavage of the bond Arg105-Val106. Cleavage at Arg55-Leu56, on the other hand, appeared to lead to inactivation of Am-beta-trypsin. The kinetic properties of the catalytic hydrolyses of synthetic substrates and the affinity to Gly-Gly-Arg immobilized on Sepharose were compared among Am-delta-, Am-beta-, and Am-alpha-trypsins. Am-delta-trypsin resembled Am-beta-trypsin in these properties, but did not resemble Am-alpha-trypsin which had a cleavage at Lys131-Ser132.

Amino Acids↗