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Biomedical subjects

K Yamane

Publications and source records attributed to K Yamane.

At least 271 records · Page 15Linked to original sources
PubMed1988

Swelling of neuronal processes in motor neuron disease.

We investigated serial sections of the anterior horns of the lower lumbar cord by a modified Bielschowsky's silver impregnation, in a case of sporadic lower motor neuron disease. We paid special attention to any direct connection between the swellings of neuronal processes and the perikarya. Focal swellings of neuronal processes were occasionally directly connected with the perikarya; some had morphologic peculiarities of axons, and others originated in dendrites.

Aged↗
PubMed1987

Modulation of Bacillus subtilis alpha-amylase promoter activity by the presence of a palindromic sequence in front of the gene.

Upstream of the promoter of the Bacillus subtilis alpha-amylase gene (amyE) derived from an alpha-amylase hyper-producing strain, there is an inverted repeat sequence (palindromic sequence), which has a free energy of 21.2 kcal/mol due to the formation of stable stem-loop structure. The role of the palindromic sequence for the expression of amyE was studied using a plasmid encoding the amyE'-'bla (E. coli beta-lactamase) fused gene in an alpha-amylase-deficient B. subtilis mutant as the host. By the presence of the palindromic sequence, the transcription activity of the amyE promoter was enhanced approximately 6 fold by starch (3%) in the medium and was less repressed by glucose.

Bacillus subtilis↗
PubMed1987

In vitro translocation of protein across Escherichia coli membrane vesicles requires both the proton motive force and ATP.

The energy requirement for protein translocation across membrane was studied with inverted membrane vesicles from an Escherichia coli strain that lacks all components of F1F0-ATPase. An ompF-lpp chimeric protein was used as a model secretory protein. Translocation of the chimeric protein into membrane vesicles was totally inhibited in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) or valinomycin and nigericin and partially inhibited when either valinomycin or nigericin alone was added. Depletion of ATP with glucose and hexokinase resulted in the complete inhibition of the translocation process, and the inhibition was suppressed by the addition of ATP-generating systems such as phosphoenolpyruvate-pyruvate kinase or creatine phosphate-creatine kinase. These results indicate that both the proton motive force and ATP are required for the translocation process. The results further suggest that both the membrane potential and the chemical gradient of protons (delta pH), of which the proton motive force is composed, participate in the translocation process.

Adenosine Triphosphate↗
PubMed1987

Protein processing to form extracellular thermostable alpha-amylases from a gene fused in a Bacillus subtilis secretion vector.

A thermostable alpha-amylase gene (amyT631) from Bacillus stearothermophilus A631 was cloned into pBR322 and recloned into pUB110: the resulting plasmid was designated pTUB607. To investigate the processing from preproenzyme to mature enzyme, amyT631 from pTUB607, after digestion with BAL31, was introduced into the B. subtilis alpha-amylase secretion vector pTUB285. Three chimaeric plasmids, pTUB613, pTUB616, and pTUB617, were isolated. The fused alpha-amylases expressed from the three plasmids seemed to be synthesized as preproenzymes. From analysis of the NH2-terminal amino acid sequences of purified extracellular alpha-amylases, the precursors of the fused enzymes appeared to be cleaved at first between amino acids 31 and 32 from the translation initiator Met (positions -11 and -10 with respect to the beginning of the mature enzyme), and processed to mature extracellular enzymes in which the NH2-terminal amino acid sequences were the same as that of the parental pTUB607 alpha-amylase, in spite of the lengths of the prosequences and the amino acid composition near the secondary cleavage sites being different in each enzyme.

Amino Acid Sequence↗
PubMed1987

Secretion of Bacillus subtilis alpha-amylase in the periplasmic space of Escherichia coli.

The Bacillus subtilis alpha-amylase structural gene (amyE) lacking its own signal peptide coding sequence was joined to the end of the Escherichia coli alkaline phosphatase (phoA) signal peptide coding sequence by using the technique of oligonucleotide-directed site-specific deletion. On induction of the phoA promoter, the B. subtilis alpha-amylase was expressed and almost all the activity was found in the periplasmic space of E. coli. The sequence of the five amino-terminal amino acids of the secreted polypeptide was Glu-Thr-Ala-Asn-Lys-, and thus the fused protein was correctly processed by the E. coli signal peptidase at the end of the phoA signal peptide.

Bacillus subtilis↗
PubMed1987

Nucleotide sequence of the beta-cyclodextrin glucanotransferase gene of alkalophilic Bacillus sp. strain 1011 and similarity of its amino acid sequence to those of alpha-amylases.

The nucleotide sequence of the gene for cyclodextrin glucanotransferase of alkalophilic Bacillus sp. strain 1011 was determined. The deduced amino acid sequence at the NH2-terminal side of the enzyme showed a high homology with the sequences of alpha-amylase in the three regions which constitutes the active centers of alpha-amylases.

Amino Acid Sequence↗
PubMed1986

Secretion activities of Bacillus subtilis alpha-amylase signal peptides of different lengths in Escherichia coli cells.

The B. subtilis alpha-amylase promoter and signal peptide are functional in E. coli cells. DNA fragments coding for signal peptides with different lengths (28, 31, 33 and 41 amino acids from the translation initiator Met) were prepared and fused with the E. coli beta-lactamase structural gene. In B. subtilis cells, the sequences of 31, 33 and 41 amino acids were able to secrete beta-lactamase into the surrounding media, but the 28 amino acid sequence was not. In contrast, all of the four sequences were able to export beta-lactamase into the periplasmic space of E. coli cells. Thus, the recognition of the B. subtilis alpha-amylase signal peptide in E. coli cells seems to be different from that in B. subtilis cells.

Amino Acid Sequence↗
PubMed1986

Amplification of the amyE-tmrB region on the chromosome in tunicamycin-resistant cells of Bacillus subtilis.

In a class of tunicamycin-resistant mutants (tmrA7) of Bacillus subtilis, the production of extracellular alpha-amylase is increased by about five fold. The tmrA7 characteristics (tunicamycin resistance and hyperproduction of extracellular alpha-amylase) can be transferred to recipient cells by transformation. In the transformants and the original tmrA7 mutant, typical amplification of the region from 4 kb upstream of the amyE gene to the tmrB gene on the chromosome was detected. The repeating unit, 16 kb in size, repeats tandemly about five and ten times in the mutant and transformants, respectively, and the alpha-amylase production is proportional to the copy number of the amyE gene. Simultaneous amplification of the tmrB gene, which is responsible for tunicamycin resistance in the multicopy state, and the alpha-amylase structural gene (amyE) seems to be the cause of the pleiotropy of the tmrA7 mutation.

Bacillus subtilis↗
PubMed1986

An explanation of the induction of mutations by 2-aminopurine from an ab initio molecular orbital study.

The molecular mechanism of induction of mutations by 2-aminopurine (AP) was studied by an ab initio molecular orbital method. Cytosine (C) is converted to its disfavored imino tautomer more easily than AP, judging from the calculated total energies of the bases and the base analogue. This suggests that a stable AP:C base mispair via two hydrogen bonds can be formed with the imino tautomer of C. These results stress the importance of the imino form of C in AP-induced mutagenesis and support the 'trigger mechanism', in which formation of one hydrogen bond between AP and C is considered to stimulate the tautomeric shift of AP or C. The calculated relative stabilities of various base pairs and mispairs were in good agreement with experimental findings.

2-Aminopurine↗
PubMed1986

Two tandemly located promoters, artificially constructed, are active in a Bacillus subtilis alpha-amylase secretion vector.

An 85 bp DNA fragment, the nucleotide sequence of which had 84% homology with the sequence for the promoter, ribosome binding site and NH2-terminal five amino acids of the Bacillus amyloliquefaciens alpha-amylase gene, was chemically synthesized. In order to analyze the promoter activity of a Bacillus subtilis alpha-amylase secretion vector, the fragment was inserted between the promoter and signal peptide-coding region of Bacillus subtilis alpha-amylase gene. Both promoters, tandemly repeated, functioned in transcribing the B. subtilis alpha-amylase signal peptide-coding region followed by the Escherichia coli beta-lactamase structural gene. The transcription initiation sites were determined by the primer extension method. The extracellular production of beta-lactamase was stimulated by two promoters as compared with that by the plasmids containing either promoter region alone. The change of two amino acids in the NH2-terminal region of the B. subtilis alpha-amylase signal peptide had no effect on the secretion of beta-lactamase from B. subtilis cells.

Bacillus subtilis↗
PubMed1986

Treatment of amyotrophic lateral sclerosis with thyrotropin-releasing hormone (TRH).

Despite the efforts of many workers, the cause and therapy has not been clarified. We carried out the therapeutic trial of thyrotropin releasing hormone (TRH) for amyotrophic lateral sclerosis (ALS) from January, 1979 to January, 1983. There were 16 subjects. The patients were given a low dose (0.5-2 mg) of TRH intravenously or intramusculary. Mild to moderate improvement was found in 9 (56%) of 16 patients. TRH has been reported to have the activating effects on the pyramidal tract, brainstem motor nuclei, and motoneuron in the spinal cord as a neurotransmitter or neuromodulator. We thought such action of TRH to be useful to the therapy of ALS.

Adult↗