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Biomedical subjects

K Yoda

Publications and source records attributed to K Yoda.

At least 127 records · Page 7Linked to original sources
PubMed1984

Transport of calcium, germanium and rubidium ions in rice seedlings in deuterium oxide.

Deuterium oxide affected all types of transport processes of ions in rice seedlings. The processes of the active transport of Rb+, the passive diffusion of Ca2+, and the preferential and specific absorption of Ge by the seedlings in D2O solutions, were suppressively distorted by D2O. The suppressive effect on the translocation of all ions studied and the absorption of Rb+, was greater with higher concentrations of D2O. However, clear-cut relations of the effect of increasing D2O concentrations on the ion transport were not obtained. The extent of the replacement of H2O by D2O in the plant appeared to affect the movement of ions in the plant.

Biological Transport↗
PubMed1983

Primer RNA for DNA synthesis on single-stranded DNA template in a cell free system from Drosophila melanogaster embryos.

A cytoplasmic extract of Drosophila melanogaster early embryos supported DNA synthesis which was dependent on an added single stranded DNA template, phi X174 viral DNA. The product DNA made during early reaction was about 100 to 600 nucleotides in length and complementary to the added template. After alkali treatment, 70 to 80 per cent of the product DNA chains exposed 5'-hydroxyl ends, suggesting covalent linkage of primer RNA at their 5'-ends. Post-labeling of 5'-ends of the product DNA with polynucleotide kinase and [gamma-32P]ATP revealed that oligoribonucleotides, mainly hexa- and heptanucleotides, were covalently linked to the 5'-ends of the majority of the DNA chains. The nucleotide sequence of the linked RNA was mainly 5'(p)ppApA(prN)4-5, where tri- (or di-) phosphate terminus was detected by the acceptor activity for the cap structure with guanylyltransferase and [alpha-32P]GTP. The structure of this primer RNA was comparable to that of the octaribonucleotide primer isolated from the nuclei of Drosophila early embryos.

Animals↗
PubMed1983

Noninvasive assessment of microcirculation of living organs and tissues using laser.

For studying microcirculation of intact tissues or organs, a new noninvasive, heat-transient method using laser photoexcitation is described. As a heating source an argon ion laser or R6G dye laser was used via a quartz fiber optic guide. Infrared radiation from heated tissue was detected by a thermography apparatus. After switching the laser irradiation on and off, a thermal transient curve of a model tissue, the skin, was biphasic: a component with a fast time constant and the other with a slow time constant. The temperature increases of both phases following laser irradiation were linear to the applied power from the laser onto the tissue. The temperature rises as a function of the wavelength of irradiated light have shown that the absorption of the light by tissue hemoglobin is a main heat-generation source. Furthermore, the temperature rises as a function of tissue blood volume and flow have shown that the component with a slow time constant is more related to the tissue hemoglobin concentration and tissue blood flow and heat conductivity. Thus, the analysis of heat-transient curves following laser irradiation gives information as to regional tissue blood volume, blood flow, and tissue heat conductivity.

Animals↗
PubMed1983

Multi-enzyme membrane electrodes for determination of creatinine and creatine in serum.

An enzyme electrode system for the determination of creatinine and creatine was developed by utilizing three enzymes: creatinine amidohydrolase (CA), creatine amidinohydrolase (Cl), and sarcosine oxidase (SO). These enzymes were co-immobilized onto the porous side of a cellulose acetate membrane with asymmetric structure, which has selective permeability to hydrogen peroxide. Two kinds of multi-enzyme electrodes were constructed by combining a polarographic electrode for sensing hydrogen peroxide and an immobilized CA/Cl/SO membrane or Cl/SO membrane for creatinine plus creatine or creatine, respectively. The multi-enzyme electrodes responded linearly up to 100 mg of creatinine and creatine per liter in human serum. Response time was 20 s in the rate method and the detection limit was 1 mg/L. Only 25 microL of serum sample is required. Analytical recoveries, precisions, and correlations with the Jaffé method were excellent, and the multi-enzyme electrodes were sufficiently stable to perform more than 500 assays. No loss of activity of immobilized enzymes was observed after nine months of storage at 4 degrees C in air.

Amidohydrolases↗
PubMed1983

[Abnormal expression of isoactin genes].

Cytoplasmic isoactins of mouse fibroblast L-cells were examined by two-dimensional gel electrophoresis. In contrast to other cultured cell lines, which contain both beta- and gamma-actins. L-cells contained only beta-actin species. When RNA of L-cells were translated in a nuclease-treated reticulocyte lysate system, actin synthesized in vitro also appeared as only beta-actin. After digestion of genomic DNAs of both L-cells and mouse brain, which contains beta- and gamma-actins, by Eco RI, Hind III, Bam HI and Sal I, obtained fragments were investigated by Southern blott analysis using 32P -labeled probe constructed from PA1 which carries a full length copy of chicken beta-actin mRNA. No differences in the patterns were detected between L-cell and brain DNAs. This result suggests that the absence of gamma-actin expression in L-cells is not due to gross deletions, insertions or rearrangements of isoactin genes. However, the use of the isoschizomeric pair of restriction enzymes, Hpa II and Msp I, resulted in different patterns of isoactin genes, implying a possible involvement of methylation in regulation of isoactin gene expression.

Actins↗
PubMed1982

Interaction of N-ethyl-N'-nitro-n-nitrosoguanidine with nucleic acids and proteins in comparison with N-methyl-N'-nitro-N-nitrosoguanidine.

Reactivity of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) was studied in comparison with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The radioactivity of [guanidino-14C]-ENNG was incorporated only into the protein fraction and that of [ethyl-14C]ENNG was incorporated into DNA, RNA and protein fractions in ascites hepatoma AH7974 cells, as were those of [guanidino-14C]- and [methyl-14C]MNNG, respectively. The amounts of the binding of ENNG were less than those of MNNG, especially in the corporation of the ethyl moiety of ENNG into nucleic acid fractions. In a non-cellular system, the radioactivity of [guanidino-14C]ENNG was incorporated into proteins, preferentially into basic proteins such as cytochrome c, but was not incorporated into nucleic acids. This behavior is similar to that of [guanidino-14C]MNNG, while the amount of binding of the former was about half of that of the latter. The radioactivity of [ethyl-14C]ENNG was also incorporated into basic proteins to almost the same extent as that of [methyl-14C]MNNG. However, the binding of the ethyl moiety of ENNG to nucleic acids was much lower than that of the methyl moiety of MNNG. Horse heart cytochrome c, bovine pancreatic RNase A and regenerating rat liver chromatin had altered their biological activities to various degrees after modification by ENNG or MNNG.

Animals↗
PubMed1982

Induction of morphological differentiation in cultured mouse neuroblastoma cells by alkylating agents.

A series of N-alkyl-N-nitrosoureas, which produce both alkylation and carbamoylation, was found to induce neurite formation in mouse neuroblastoma N-18 cells just as does N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Related compounds, which produce only carbamoylation or nitroguanidination, did not induce morphological differentiation, while methyl methanesulfonate (MMS) and dimethyl sulfate, which produce only alkylation, did. MNNG, methyl nitrosourea and MMS were more effective in the induction of differentiation than their corresponding ethyl derivatives. These data suggested that alkylation contributed to the induction of morphological differentiation in N-18 cells.

Alkylating Agents↗
PubMed1981

The nucleotide sequence of the promoter and the amino-terminal region of alkaline phosphatase structural gene (phoA) of Escherichia coli.

The promoter and the amino-terminal region of phoA, the structural gene for alkaline phosphatase of Escherichia coli K12, was cloned by using a promoter cloning vector pMC1403. The nucleotide sequence of the cloned fragment has been determined. A sequence encoding the amino-terminal portion of mature alkaline phosphatase is found and it is preceded by a sequence encoding the signal peptide. The signal peptide consists of 21 amino acids; Met-Lys-Gln-Ser-Thr-Ile-Ala-Leu-Ala-Leu-Leu-Pro-Leu-Leu-Phe-Thr-Pro-Val-Thr-Lys-Ala. The translation initiation codon is GUG, which is preceded by the Shine-Dalgarno sequence GGAG. Upstream to these sequences, there is a typical procaryotic promoter. TATAGTC for the Pribnow box. Around the Pribnow box, there are several dyad symmetrical sequences, which may probably be concerned with the regulation of this gene.

Alkaline Phosphatase↗