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Biomedical subjects

T Ohno

Publications and source records attributed to T Ohno.

At least 955 records · Page 53Linked to original sources
PubMed1975

Purification of RNA-instructed DNA polymerase from human leukemic spleens.

Particles possessing a density of 1.16 g/ml and encapsulating a 70S RNA and a RNA-instructed DNA polymerase (reverse transcriptase) have been prepared from the spleen of a patient with chronic lymphocytic leukemia. These particles have been converted to cores with a density of 1.26 g/ml and containing the enzyme-RNA complex, in complete analogy to the known RNA tumor viruses of avian and murine origin. The reverse transcriptase was purified from the cores by column chromatography to a stage showing a single major protein band of 70,000 daltons in a gel electrophoresis. The enzyme was capable of transcribing heteropolymeric RNA into DNA complements as demonstrated by specific back hybridization to template RNA. The leukemic spleen would appear to represent an important source of this enzyme, as well as other potentially important leukemia-specific reagents.

Enzyme Activation↗
PubMed1975

Inhibition of 6-methylsalicyclic acid synthesis by the antibiotic cerulenin.

Cerulenin, a specific inhibitor of beta-ketoacyl-(acyl carrier protein) synthetase [EC 2.3.1.41] and 3-hydroxy-3-methylglutaryl-CoA synthetase [EC 4.1.3.5], was studied to determine whether it inhibits 6-methylsalicylic acid synthesis, in which so-called "polyketide" formation, a condensation step similar to that in fatty acid synthesis, is involved. In fact, 100 mug/ml (4.5 X 10(-4) M) of cerulenin inhibited 60% of 6-methylsalicylic acid synthetase activity and 68% of fatty acid synthetase activity of Penicillium urticae.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed1975

Assembly of tobacco mosaic virus in vitro. Improved model for the elongation process by protein subunits.

The in vitro assembly reaction of tobacco mosaic virus (TMV), especially the elongation process of partially reconstituted RNA (PRR) by protein subunits, was observed by electron microscopy. After addition of TMV-protein subunits, the PRR appeared as rods with a clump at one end, believed to be a complex between added protein subunits and the RNA tail protruding from PRR. The subunits entrapped on the RNA tails in the forms of clumps were progressively incorporated into the growing rods on incubation, ending with the formation of completely reconstituted rods. The clumps were also observed after addition of cucumber green mottle mosaic virus (CGMMV) protein subunits to rods partially reconstituted from RNA and TMV-protein. In this case, the protein subunits, seen as clumps, did not become incorporated to form elongating rods. An improved model for the elongation of TMV rods is proposed. The elongation process is composed of two steps, with the first step being the interaction of protein subunits with the RNA tail protruding from the growing rod. Any protein having a specific binding site for TMV-rna, not limited to TMV-protein, will react in the first step. The second step is the incorporation of the protein on the RNA tail into a rod-shaped structure, with consequent elongation of the growing rod. It appears that only protein homologous with that in the partially reconstituted rods can partake in the second step.

Microscopy, Electron↗
PubMed1975

Osteogenic sarcoma. A study of one hundred and thirty cases.

One hundred and thirty patients with osteogenic sarcoma were studied clinically, roentgenographically, and pathologically. Prognosis by each of ten factors was analyzed with the Wilcoxon test. The test yielded p smaller than 0.05 in a comparison between the survival curves of patients fifteen years old or younger and that of patients over fifteen, but other comparisons did not yield p smaller than 0.05. The actual five-year survival rate was 25.5 per cent (twenty-six of 102 patients who had radical surgery). Our therapeutic regimen for osteogenic sarcoma at the present time consists of regional perfusion, amputation, bronchial artery infusion, and systemic administration of anticancer agents.

Adolescent↗
PubMed1974

Mechanism of action of CM-55, a synthetic analogue of the antilipogenic antibiotic cerulenin.

CM-55 is a synthetic analogue of the antibiotic cerulenin with the chemical structure of 2, 3-dodecenyl-4-oxo-dimethyl amide. This compound inhibited the growth of Saccharomyces cerevisiae ATCC 12341 and inhibited protein and lipid synthesis by 91 and 95%, respectively, at a concentration of 50 mug/ml (2.1 x 10(-4) M). The inhibition of protein synthesis was associated with the partial reduction of ribonucleic acid synthesis and leucine transport. The mechanism of inhibition of lipid synthesis was further investigated in a cell-free extract of the yeast. CM-55 inhibited the incorporation of [(14)C]acetyl Coenzyme A (CoA) into both fatty acid (FAF) and non-saponifiable fractions (NSF). However, it did not inhibit [(14)C]malonyl CoA incorporation into FAF and only slightly inhibited [(14)C]mevalonate incorporation into NSF. The activity of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) synthase was inhibited more strongly than the incorporation of [(14)C]3-hydroxy-3-methylglutaryl CoA into NSF; this could account for the CM-55 inhibition of [(14)C]acetyl CoA incorporation into NSF.

Acetates↗
PubMed1969

Demonstration of the universality of the genetic code in vivo by comparison of the coat proteins synthesized in different plants by tobacco mosaic virus RNA.

The amino acid sequence of the coat protein of tobacco mosaic virus (TMV) synthesized in the garden zinnia (Compositae family) is compared with that synthesized in tobacco (Solanaceae family) by using the same preparation of TMV-RNA as messenger. The Compositae family is the most advanced group, and the Solanaceae family is a relatively advanced group in the plant kingdom. Both amino acid sequences are identical, including acetylserine as the N-terminal amino acid. This gives direct evidence that the RNA codon in vivo in the plant kingdom is universal between Compositae and Solanaceae families.

Amino Acid Sequence↗