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71.
A P Reddy B L Hsu P S Reddy N Q Li K Thyagaraju C C Reddy M F Tam C P Tu 《Nucleic acids research》1988,16(12):5557-5568
We have characterized a cDNA pGPX1211 encoding rat glutathione peroxidase I. The selenocysteine in the protein corresponded to a TGA codon in the coding region of the cDNA, similar to earlier findings in mouse and human genes, and a gene encoding the formate dehydrogenase from E. coli, another selenoenzyme. The rat GSH peroxidase I has a calculated subunit molecular weight of 22,155 daltons and shares 95% and 86% sequence homology with the mouse and human subunits, respectively. The 3'-noncoding sequence (greater than 930 bp) in pGPX1211 is much longer than that of the human sequences. We found that glutathione peroxidase I mRNA, but not the polypeptide, was expressed under nutritional stress of selenium deficiency where no glutathione peroxidase I activity can be detected. The failure of detecting any apoprotein for the glutathione peroxidase I under selenium deficiency and results published from other laboratories supports the proposal that selenium may be incorporated into the glutathione peroxidase I co-translationally. 相似文献
72.
73.
74.
Myocyte deenergization and intracellular free calcium dynamics 总被引:1,自引:0,他引:1
75.
J H Rankin M Landauer N Neaves Q Tian T M Phernetton 《Journal of developmental physiology》1988,10(5):393-398
We have tested the hypotheses that systemic responses to the infusion of prostaglandin I2 may have masked the ability of this substance to dilate the maternal placenta and that the inability of prostaglandin I2 to dilate the maternal near-term placenta may be a function of placental age. Regional blood flows were measured with radioactive microspheres. In 8 near-term sheep the control flows were measured and angiotensin II (AII) infusion was begun at 5 micrograms/min and continued for the duration of the experiments. At t = 15 min, regional blood flows were again measured. Prostaglandin I2 was then infused via a retrograde uterine arterial catheter at 10 micrograms/min. At t = 30 min, the flows were again measured. At this time the infusion of prostaglandin I2 was stopped and at t = 45 min the blood flows were measured for the last time. AII increased the resistance of all tissues examined. The blood pressure increased with AII and did not change thereafter. The non-placental uterine tissue served by the retrograde catheter dilated with prostaglandin I2. The placental tissue had an initial resistance of 59 +/- 6 mmHg.ml-1.min.g which increased to 98 +/- 22 mmHg.ml-1.min.g with the infusion of AII (P less than 0.05). This resistance remained constant at 82 +/- 19 mmHg.ml-1.min.g with the administration of prostaglandin I2 and did not change after prostaglandin I2 was removed. The local application of prostaglandin I2 in the presence of AII induced vasoconstriction caused vasodilatation in the nonplacental vessels but could not change the AII induced constriction in the placental vasculature.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
76.
Zero-stress states of arteries 总被引:9,自引:0,他引:9
The no-load configuration of a living organ is, in general, not the zero-stress state. The difference can be revealed by cutting up an unloaded organ to such an extent that the stress becomes zero in the tissue everywhere. For the aorta, it is shown that the configuration of the zero-stress state differs considerably from being a cylindrical tube. It is, in fact, an open sector with opening angles varying along the arterial tree. This article presents data on the zero-stress state in the arteries of the rat in normal condition. 相似文献
77.
E J Gibbs M C Maurer J H Zhang W M Reiff D T Hill M Malicka-Blaszkiewicz R E McKinnie H Q Liu R F Pasternack 《Journal of inorganic biochemistry》1988,32(1):39-65
Studies of the solution properties of gold(III)tetrakis(4-N-methylpyridyl) porphine and its DNA binding characteristics have been conducted utilizing uv/vis absorption spectroscopy, circular dichroism (CD), Mossbauer spectroscopy, and temperature-jump relaxation techniques. These studies indicate that over the concentration range considered this water soluble gold(III) porphyrin does not aggregate, binds axial ligands only weakly with a preference for soft Lewis bases, and is capable of intercalation into nucleic acids of appropriate base pair content. The interaction of this and several other porphyrins with the synthetic polynucleotide poly(dA-dC).poly(dT-dG) has been studied. Spectroscopic signatures for intercalation were found for those derivatives not having axial ligands. Intercalation into chromatin in vitro can also occur with those porphyrins and metalloporphyrins which do not have axial ligands. Finally, studies utilizing microinjection techniques indicate that once within the cell, tetrakis(4-N-methylpyridyl)porphine tends to localize in the nucleus. 相似文献
78.
M. A. Malek N. A. Chowdhury Q. M. Youssouf N. Choudhury 《Enzyme and microbial technology》1988,10(12):750-753
Five locally isolated bacterial strains produced extracellular cellulase enzymes, primarily CMCase, when grown on different natural and commercial cellulosic substrates. Extracellular CMCase and avicelase activity was higher with the strain CLS-32, a Cytophaga sp., compared to four other strains. The whole-cell preparations of these isolates were found to saccharify cellulosic substrates to reducing sugars. Maximum release of reducing sugar (5.75 mg ml−1) was obtained with CLS-32 using sugar cane bagasse as growth and hydrolysis substrates. 相似文献
79.
Using DAPI, rabbit antitubulin antibody, FITC-labeled goat anti-rabbit IgG, and TRITC-phalloidin to stain individual cells, the microspectrophotometric analysis showed that three markers that represent the nucleus, microtubules (MT), and microfilaments (MF), respectively, could be recognized in individual cells without interference. The phase of the cell cycle was determined by DNA content. We found that in Indian muntjac (IM) cells, the amount of tubulin in G2 and M phases was about twice as much as that in G1 phase. In G2 cells, the cytoplasmic microtubule complex (CMTC) became denser than in G1 cells. The cytoplasmic MT extent in basically the same orientation as MF bundles in interphase. The regions where the MT is denser also have a denser MF distribution. 相似文献
80.
A V79 Chinese hamster cell line XR-V15B exhibiting hypersensitivity to X-ray has been isolated and characterized. Additionally to increased X-ray-sensitivity (approximately 8-fold, as judged by D10 values), cross-sensitivity to bleomycin (3-fold increase), 4NQO (3-fold), H2O2, EMS, MMS (2-fold) were observed also. No increased sensitivity to UV and MMC was found. Genetic complementation analysis indicates that XR-V15B belongs to the same complementation group as the X-ray-sensitive (xrs) mutants of Chinese hamster ovary (CHO) cells described by Jeggo (1985). Biochemical analysis of XR-V15B confirms this finding: the mutant showed a decreased ability to rejoin double-strand breaks induced by X-ray as measured by neutral elution. After 4 h of repair more than 50% of the double-strand breaks remain in comparison to 3% in V79 cells. No difference was observed between wild-type and XR-V15B cells in the initial number of single-strand breaks induced, in the kinetics of their rejoining and in the final level of unrejoined single-strand breaks. Treatment with 5-azacytidine did not have an effect on the reversion frequency of XR-V15B, contrary to the results obtained with the xrs mutants. XR-V15B has been grown in continuous culture for more than 3 months without evidence of reversion. The mutation induction by X-ray irradiation at the HPRT locus is not significantly increased in the mutant, but at doses giving the same degree of cell killing, XR-V15B cells are hypomutable. 相似文献