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Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 811 records · Page 45Linked to original sources
PubMed1987

Molecular cloning and sequencing of cDNA for rat cathepsin H. Homology in pro-peptide regions of cysteine proteinases.

A cDNA for rat cathepsin H was isolated and sequenced. The deduced protein comprising 333 amino acid residues is composed of a typical signal sequence (21 residues), a pro-peptide region (92 residues) and a mature enzyme region (220 residues). The amino acid sequence in the pro-peptide region, in particular, residues Phe-(-41) to Ser-(-29) of cathepsin H, is highly homologous to the pro-peptide regions of other cysteine proteinases. This homologous region may play a role in the processing of cysteine proteinases.

Amino Acid Sequence↗
PubMed1987

Analysis of the chromosomal abnormalities of a woodchuck hepatocellular carcinoma-derived cell line (WH257GE10).

The normal woodchuck karyotype was determined by the G-banding technique, and the chromosomal abnormalities of a woodchuck hepatocellular carcinoma-derived cell line (WH257GE10) were analyzed and compared with it. The normal woodchuck karyotype was 38,XY in a male, and 38,XX in a female. Autosomes were classified into 2 groups (A and B). Group A consisted of 13 pairs (1-13) of metacentric or sub-metacentric chromosomes, and group B consisted of 5 pairs (14-18) of telocentric or sub-telocentric ones. The X chromosome was sub-metacentric, and the Y chromosome was telocentric. In WH257GE10, the modal number was 36. Deletion of one of the chromosome 5 pair, of the chromosome 13 pair, and of the Y chromosome was observed. Two marker chromosomes (M1 and M2) were found. These markers showed the same G-banded patterns except for a small chromosome fragment at the distal part of the long arm of M1. The chromosome aberrations were very stable through successive passages in vitro. These findings suggest that the chromosomal abnormalities found in WH257GE10 might be associated with the pathogenesis of woodchuck hepatocellular carcinoma.

Animals↗
PubMed1987

Primary structures of human protein kinase C beta I and beta II differ only in their C-terminal sequences.

Two types of cDNA clones encoding human protein kinase C (PKC) were isolated from a spleen cDNA library using rabbit protein kinase C beta I/beta II cDNA as a hybridization probe. Nucleotide sequence analyses of these cDNA inserts revealed complete primary structures of two distinct types of human protein kinase C beta I and beta II which differ only in their C-terminal 50 or 52 amino acid residues. It was concluded that there exist four distinct types of PKC, PKC alpha, beta I, beta II and gamma, in human as well as rabbit, and that the corresponding sequences are strictly conserved among mammalian species.

Amino Acid Sequence↗
PubMed1987

Molecular cloning of a cDNA coding for human leukotriene A4 hydrolase. Complete primary structure of an enzyme involved in eicosanoid synthesis.

We have isolated a near full-length cDNA encoding human leukotriene A4 hydrolase, which synthesizes a potent chemotactic and spasmogenic compound, leukotriene B4. A human spleen cDNA library was screened with a 48-mer oligonucleotide probe, synthesized according to the partial amino acid sequence of the human leukocyte enzyme. The nucleotide sequence of the cDNA had an open reading frame of 1,833 base pairs, which contained regions coding for the N-terminal amino acid sequence, the amino acid sequence for the probe design, and several other peptide sequences of the enzyme. The complete primary structure of the enzyme composed of 610 amino acid residues (molecular weight, 69,153) was deduced from the cDNA.

Amino Acid Sequence↗
PubMed1987

A yeast gene coding for a putative protein kinase homologous to cdc25 suppressing protein kinase.

A yeast gene termed YKR coding for a putative protein kinase was isolated by using the cloned cDNA for rabbit protein kinase C as a hybridization probe. The encoded protein (YKR), composed of 380 amino acid residues, shows extensive sequence homology to serine/threonine-specific protein kinases from various species in the approx. 320 C-terminal amino acid residues, strongly suggesting that YKR is endowed with a protein kinase activity. The observed homologies to the cdc25 suppressing protein kinase from yeast, the catalytic subunit of mammalian cAMP-dependent protein kinase, and mammalian protein kinase C were 76, 48 and 37%, respectively. Gene replacement experiments showed that YKR itself is not essential for cell proliferation.

Amino Acid Sequence↗
PubMed1987

Calcium-activated neutral protease and its endogenous inhibitor. Activation at the cell membrane and biological function.

The structures of calcium-activated neutral protease (CANP) and its endogenous inhibitor elucidated recently have revealed novel features with respect to their structure-function relationship and enzyme activity regulation. The protease is regarded as a proenzyme which can be activated at the cell membrane in the presence of Ca2+ and phospholipid, and presumably regulates the functions of proteins, especially membrane-associated proteins, by limited proteolysis. Protein kinase C is hydrolysed and activated by CANP at the cell membrane to a cofactor-independent form. These results are reviewed and the possible involvement of CANP in signal transduction is discussed.

Animals↗
PubMed1987

Atavistic mutations reflect the long life span of dispensable genes.

Most of the major innovations in evolution occurred at the very beginning of life on this earth some 3.5 billion years ago before the division of eukaryotes from prokaryotes. This initial innovativeness was due, in no small part, to the peculiar construction of primordial coding sequences that were repeats of base oligomers, the number of bases in oligomeric units not being a multiple of three. Such coding sequences are conferred with a measure of immortality. Because of this initial immortality and of long life span of genes after becoming dispensable, the ancient gene may remain silenced in particular phylogenetic trees for a very long time, only to be resurrected later. Hemoglobin genes expressed in exceptional bacteria, plants, worms, insects, as well as in all vertebrates are a good example of this. Atavistic mutations are more dramatic visible examples of such resurrection of long dormant genes. A few interesting examples are given.

Animals↗
PubMed1987

Repetition as the essence of life on this earth: music and genes.

In prebiotic nucleic acid replication, templates appear to have been in short supply. A single round of tandem duplication of existing oligomers assured progressive extension of templates to the length adequate for encoding of polypeptide chains. Thus, the first set of coding sequences had to be repeats of base oligomers encoding polypeptide chains of various periodicities. On one hand, the readiness of these periodical polypeptide chains to assume alpha-helical and/or beta-sheet secondary structures contributed to the extremely rapid initial functional diversification of these polypeptide chains. It would be recalled that most, if not all, of the sugar-metabolizing enzymes had already achieved the inviolable functional competence before the division of prokaryotes from eukaryotes. On the other hand, a certain (dipeptidic?) of the peptidic periodicities was apparently chosen as the timekeeping unit by the biological clock. Musical compositions too apparently evolved originally as a timekeeping device. Accordingly, repetitiousness is evident in all musical compositions. Evolution of musical compositions from the early Baroque to the late Romantic parallels that of coding sequences from rather exact repeats of base oligomers to more complex modern coding sequences in which repetitious elements are less conspicuous and more varied. Inasmuch as the earth is governed by the hierarchy of periodicities (days, months and years), such reliance on periodicities is rather expected.

Amino Acid Sequence↗
PubMed1987

Immunocytochemical study of the intracellular localization of M protein of vesicular stomatitis virus.

The purpose of this paper is to describe the immunocytochemical localization of M protein of vesicular stomatitis virus (VSV) in infected cells. Vero cells, MDBK cells, Swiss 3T3 cells, and BHK cells were examined at various times after infection. For immunofluorescent staining, the cells were fixed with PLP fixative and then treated with 0.05% Triton X-100 before incubation with antibodies. Three hours after infection, M protein exhibited diffuse immunostaining throughout the cytoplasm and later accumulated along the cell membrane. The localization of M protein differed from the granular localization of the nucleocapsid N protein of VSV in the cytoplasm. For electron microscopy, the cells were fixed first in a mixture of 2% paraformaldehyde and 0.05% glutaraldehyde and then with PLP fixative, this being followed by treatment with 0.05% saponin. They were then immunostained using the immunoperoxidase method. The M protein was found to be distributed throughout the cytoplasm and later under the cell membrane, especially at virus budding sites. We also used postembedding immunostaining and freeze-fracture immunostaining to avoid the translocation of M protein caused by the detergent treatment. These techniques confirmed our previous results. Our findings are consistent with the view that the M protein of VSV is synthesized on free ribosomes and is then associated with the cell membrane where viral assembly may occur.

Animals↗
PubMed1987

Evolution from primordial oligomeric repeats to modern coding sequences.

It seems as though nature was most innovative at the very beginning of life on this Earth a few billion years ago. For example, the functional competence of most, if not all, of the sugar-metabolizing enzymes was clearly established before the division of eukaryotes from prokaryotes eons ago, each critical active-site amino acid sequence being conserved ever since by bacteria as well as by mammals. I contend that this initial innovativeness was due to the first set of coding sequences being repeats of base oligomers, thus encoding polypeptide chains of various periodicities; such periodical polypeptide chains can easily acquire alpha-helical and beta-sheet-forming segments. In fact, the entire length of sugar-metabolizing enzymes is comprised of alternating alpha-helical and beta-sheet-forming segments. In the prebiotic (therefore nonenzymatic) replication of nucleic acids, what was in short supply was long templates, for there apparently was no inherent obstacle in copying of long templates, if such existed, in the presence of Zn2+. I submit that in this prebiotic condition, only those nucleotide oligomers that were internal doubles were automatically assured of progressive elongation to become long templates. For example, a decamer that was a pentameric repeat and its complementary sequence may pair unequally to initiate the next round of replication: first unit pairing with second, and a paired segment serving as a primer. As a consequence of this unequal pairing, decameric templates managed to become pentadecameric templates only after one round of replication, and this elongation process had no inherent limit.

Amino Acid Sequence↗
PubMed1987

Three subtypes of chronic schizophrenia identified using 11C-glucose positron emission tomography.

The authors used positron computed tomography (CT) and 11C-labeled glucose to measure brain glucose utilization in 20 chronic schizophrenic patients (18 men, 2 women, mean age 38) and 5 male control subjects (mean age 38). Positron emission tomography (PET) revealed at least three subtypes: hypofrontal (type A), hypoparietal (right-sided disturbance in right-handed and left-sided disturbance in left-handed patients) (type B), and normal (type C). The significant count reduction in the frontal lobe (Brodmann's area 10) in type A patients was 38%, while that in the parietal lobe (Brodmann's area 40) in type B patients was 26% in each lobe of the brain.

Adolescent↗
PubMed1987

11C-glucose metabolism in manic and depressed patients.

The authors used positron emission tomography (PET) and 11C-labeled glucose to study 15 unmedicated patients with affective disorders and 7 control subjects. Diagnoses of affective disorders were based on DSM-III criteria, and symptomatology was evaluated by the Hamilton Rating Scale for Depression. Blood counts of 11C in both unipolar and bipolar patients did not differ from those in controls after oral administration of 11C-glucose. By contrast, brain counts of 11C in unipolar depressed patients were significantly lower, whereas those in bipolar manic patients were significantly higher, than in normal controls.

Adult↗
PubMed1987

Early genes that were oligomeric repeats generated a number of divergent domains on their own.

One of the more popular concepts to emerge in recent years is that new proteins evolved by domain exchanges between preexisting proteins. The presence of introns within eukaryotic genes is thought to enhance such exchanges. Yet domain exchanges must necessarily be the secondarily developed process in evolution, for they would have been effective only after multitudes of domains came into being. Many of the proteins with functionally divergent domains were established before the division of prokaryotes from eukaryotes; i.e., soon after the creation of life on this earth. I attribute the extreme innovativeness of early coding sequences to their construction; i.e., being repeats of oligomeric units. The rhodopsin family of proteins--with seven hydrophobic, alpha-helical transmembrane domains, four extracellular domains, and four intracytoplasmic domains--indeed arose before the division of prokaryotes from eukaryotes and later gave rise to muscarinic acetylcholine receptor and beta-adrenergic receptor among others. In this paper, I show that the entire coding sequence for porcine muscarinic acetylcholine receptor is still replete with copies of three heptameric units that are very closely related to each other. Original heptameric units are more stringently conserved in parts encoding the seven transmembrane domains, whereas new repeating units are comingled with the old in parts encoding extracellular and intracytoplasmic domains.

Animals↗
PubMed1987

Mutagenicity tests of the antithyroid agent thiamazole. Cytogenetic studies on male mice.

The mutagenic potential of thiamazole, an antithyroid agent, was investigated by an in vivo cytogenetic test and was compared with those of mitomycin C and vincristine. These drugs were subcutaneously injected into slc-ICR male mice either as a single dose or as multiple doses for 5 successive days. Thiamazole (90 or 180 mg/kg) did not increase the number of micronuclei in bone marrow cells. This drug also did not induce chromosomal aberrations in spermatogonium, spermatocyte, or bone marrow cells. On the other hand, mitomycin C (3.0 mg/kg) increased the appearance of chromosomal aberrations and micronuclei. Vincristine (0.2 mg/kg) induced bone marrow cells with a so called large micronucleus (d greater than or equal to D/4). These results suggest that thiamazole may not have significant effects on the genetic systems of mice.

Animals↗