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Biomedical subjects

K Yamane

Publications and source records attributed to K Yamane.

At least 289 records · Page 16Linked to original sources

Amplification and deletion of the amyE+-tmrB+ gene region in a Bacillus subtilis recombinant-phage genome by the tmrA7 mutation.

A 22.4-kilobase DNA fragment containing the tmrA7-amyR2-amyE+-tmrB+-aroI+ region of the Bacillus subtilis N7 chromosomal DNA was cloned into a recombinant B. subtilis bacteriophage, p11-AA248. The amyE+-tmrB+ gene region, approximately 12.6 kilobases, in the phage genome was amplified in a tunicamycin-resistant (Tmr) Amy+ AroI+ transductant of B. subtilis by p11-AA248. On the other hand, the amyE+-tmrB+ region in the genomes of 80 to 90% of the phage particles was deleted when the phages were induced from the Tmr Amy+ AroI+ transductants by treatment with 1.0 micrograms of mitomycin C per ml. From analyses of the physical maps and DNA nucleotide sequences in the junction region of the deleted phage genome and the parental DNA fragments, it is suggested that the deletion occurred within a direct repeat sequence composed of 18 base pairs. The endpoints of the amplified gene region seemed to be closely related to both terminal regions of the deleted DNA.

Bacillus subtilis↗

Molecular cloning, DNA nucleotide sequencing, and expression in Bacillus subtilis cells of the Bacillus macerans cyclodextrin glucanotransferase gene.

The gene for cyclodextrin glucanotransferase from Bacillus macerans was cloned in an Escherichia coli bacteriophage, lambda D69, and was recloned in a Bacillus subtilis plasmid, pUB110. Starting from an ATG initiation codon, a unique reading frame was shown to extend for 2,142 base pairs (714 amino acids). The nucleotide sequence revealed that the enzyme is composed of two identical subunits.

Amino Acids↗

Monocyte-mediated suppression of T lymphocyte blastogenesis and its reversal by deoxyguanosine. Defects in patients with systemic lupus erythematosus.

We investigated monocyte-mediated suppression of T lymphocyte blastogenesis in normals and patients with systemic lupus erythematosus (SLE). When monocytes from normals were cocultured with autologous T lymphocytes with a ratio of 1:1 and stimulated with phytohemagglutinin (PHA), 3H-thymidine incorporation by T lymphocytes was suppressed. This monocyte-mediated suppression was reversed by purine nucleoside phosphorylase substrate, deoxyguanosine. In SLE patients, both monocyte-mediated suppression and its reversal by deoxyguanosine were defective. The defective function was observed both in patients with active and inactive diseases. The defective function was studied sequentially before and after change in the clinical status of patients. The defects remained unaffected regardless of the disease activity. The defects in monocyte-mediated suppression and its reversal by deoxyguanosine in SLE patients as demonstrated in our study suggest the presence of intrinsic monocyte dysfunction in SLE.

Adult↗

Enhanced Fc receptor function of monocytes from patients with clinically active systemic lupus erythematosus: binding and degradation of soluble immune complexes in vitro.

The in vitro Fc receptor function of monocytes as measured by using soluble immune complexes (IC) consisting of ovalbumin and 125I-labeled antibody to ovalbumin was examined in serum-free medium. Adherent monocytes were obtained from peripheral blood of 18 patients with systemic lupus erythematosus (SLE; 6 active, 12 inactive) and 13 normal controls. 5 X 10(5) monocytes were incubated with soluble IC containing 20 ng IgG for 16 hr at 4 degrees C, and for 4 hr and 16 hr at 37 degrees C, and then cell-associated and acid-soluble radioactivities were counted. After 16-hr incubation at 4 degrees C, there was no significant difference in the amount of cell-associated IC between monocytes from SLE patients and those from normal controls. After 4 hr incubation at 37 degrees C, monocytes from patients with active SLE bound and phagocytized more IC than those from patients with inactive SLE or from normal controls (P less than 0.01). After 16 hr incubation at 37 degrees C, degradation of soluble IC by monocytes from patients with active SLE greatly increased (P less than 0.003). These findings were discussed in relation to the possible pathophysiologic role of the mononuclear phagocyte system in SLE.

Adult↗

Stable hyper-production of Escherichia coli beta-lactamase by Bacillus subtilis grown on a 0.5 M succinate-medium using a B. subtilis alpha-amylase secretion vector.

Extracellular production of Escherichia coli beta-lactamase by Bacillus subtilis, using a B. subtilis secretion vector constructed from its own alpha-amylase gene, was promoted when the cells were grown on LG-medium containing 0.5 M succinate under poor aeration conditions. The amount of the enzyme secreted was 50 to 60 times as large as that obtained by cultivation of the cells on LG-medium under good aeration conditions. The effect of protease-deficient mutant of B. subtilis on the enzyme production by B. subtilis was significant while that of protease inhibitors was negligible or inexistent.

Bacillus subtilis↗

Synthesis and secretion of biologically active mouse interferon-beta using a Bacillus subtilis alpha-amylase secretion vector.

Mouse interferon-beta (IFN-beta) cDNA, whose signal sequence had been removed by BAL 31 digestion, was introduced into a Bacillus subtilis secretion vector constructed by using the promoter and signal sequence of the B. subtilis alpha-amylase gene. The resultant chimeric plasmids were transferred into B. subtilis 207-25. Four kanamycin-resistant transformants were selected by both colony hybridization and a new immunoblot method for secretory proteins. They secrete the proteins which cross-react with sheep anti-mouse IFN-beta serum into the culture medium. One of them expressed a high IFN-beta activity as assayed by the L cell and vesicular stomatitis virus system, while the other three showed weak or little IFN activities. Based on our previous study [Ohmura et al., Nucl. Acids Res. 12 (1984) 5307-5319], it was suggested that the secreted IFN molecules are hybrid proteins in which the NH2-terminal region consists of part of the alpha-amylase signal peptide. Nucleotide sequence analysis revealed that plasmid pTUB502, which expressed high IFN activity, is joined to the mouse IFN-beta gene from the codon position 6 of its mature protein. The other three plasmids, pTUB506, pTUB509, and pTUB519, contain the mouse IFN-beta gene from the codon positions 3, 1, and -5, respectively. The NH2-terminal region of the mouse IFN-beta seems to be closely related to its biological activity.

Animals↗