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121.
Effects of interleukin-1 (IL-1) on FSH-induced differentiation of immature porcine granulosa cells in vitro were examined in short-term (48-h) cultures. IL-1 inhibited FSH induction of aromatase activity and of LH-stimulated cAMP accumulation by granulosa cells. Both these inhibitory actions of IL-1 were concentration-dependent. Significant inhibitory effects were observed with as low as 0.05-0.25 ng/ml of IL-1, with maximal effects at 25 ng/ml. IL-1 also significantly inhibited increases in [125I]iodo-LH binding and progesterone secretion induced by FSH, as well as reducing basal levels of aromatase activity and LH-stimulated cAMP accumulation. Studies on the mechanisms of IL-1 actions on FSH-induced differentiation of immature porcine granulosa cells revealed that IL-1 reduced cAMP accumulation by the cells in response to FSH in a time- and concentration-dependent manner. IL-1 also inhibited induction of aromatase activity and LH-stimulated cAMP accumulation induced by dibutyryl cAMP, suggesting that IL-1 also affects the steps distal to cAMP generation. In contrast, IL-1 had no effect on progesterone secretion induced by dibutyryl cAMP, suggesting that post-cAMP steps of progesterone secretion were unaffected by IL-1. 相似文献
122.
Human serum deoxyribonuclease I (DNase I) polymorphism: pattern similarities among isozymes from serum, urine, kidney, liver, and pancreas. 总被引:7,自引:0,他引:7
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K Kishi T Yasuda Y Ikehara K Sawazaki W Sato R Iida 《American journal of human genetics》1990,47(1):121-126
We have devised a zymogram method with high sensitivity and resolution for investigating molecular heterogeneity and genetic polymorphism of deoxyribonuclease I. A combination technique of polyacrylamide-gel isoelectric-focusing electrophoresis and the newly developed zymogram method have led to the discovery of genetic polymorphism of human serum DNase I. Family studies showed that the three common phenotypes--DNASE1 1, DNASE1 1-2, and DNASE1 2--and the other five relatively rare phenotypes--DNASE1 1-3, DNASE1 2-3, DNASE1 2-4, and DNASE1 3-4--represent homozygosity or heterozygosity for four autosomal codominant alleles, DNASE1 *1, DNASE1 *2, DNASE1 *3, and DNASE1 *4. The frequencies of DNASE1 *1, DNASE1 *2, DNASE1 *3, and DNASE1 *4 calculated in a Japanese population were .5517, .4358, .0104, and .0021, respectively. Moreover, it was found that urine and extracts of kidney, liver, and pancreas, as well as serum, can be used for DNase I phenotyping. 相似文献
123.
The enzyme activity of dephosphorylation of thymidine triphosphate was found in microsomal fraction of rat liver. The enzyme activity decreased at the time when [3H]thymidine incorporation into DNA of regenerating liver increased. When the [3H]thymidine incorporation was suppressed by 1,3-diaminopropane, the enzyme activity remained elevated. These results suggest that the enzyme activity appears to be closely linked to DNA synthesis. 相似文献
124.
Purification and properties of Escherichia coli protein i, a prepriming protein in phi X174 DNA replication 总被引:8,自引:0,他引:8
Protein i, one of seven Escherichia coli proteins essential for primosome initiation of DNA chains in the in vitro conversion of single-stranded phi X174 DNA to duplex replicative form, has been purified approximately 15,000-fold to more than 98% purity. The protein is an oligomer of 22,000-dalton subunits migrating as a single electrophoretic band on native, as well as on denaturing polyacrylamide gels. Estimates of a Stokes radius of 41 A, a sedimentation coefficient of 3.5 S, a Mr = 61,000, and a frictional coefficient of 1.57 suggest that native protein i is a highly asymmetric oligomer composed of three identical subunits. About 50 such molecules are present/cell. Cross-linking the protein with dimethylsuberimidate or dimethyladipimidate produced three major bands corresponding to the monomer, dimer, and trimer, as well as two minor bands corresponding to the tetramer and pentamer. Incorporation of 3H-labeled "trimeric" protein i into the prepriming replication intermediate (primosome) occurs at a stage requiring participation of dnaB and dnaC proteins, and follows the actions of proteins n, n', and n". After extension of primers by DNA polymerase III holoenzyme, protein i is not retained in the isolated primosome complex. Thus, protein i is essential in the assembly of a functional primosome, but its precise physiologic role and genetic locus are still unknown. 相似文献
125.
Immunoelectron microscopic study on interactions of noninfectious sendai virus and murine cells. 总被引:1,自引:0,他引:1
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The early interactions of LLC-MK2 cell-grown noninfectious Sendai virus and a murine cell line, P815 mastocytoma ascitic cells, were studied by electron microscopy, using the ferritin-conjugated antibody technique with anti-virus glycoprotein serum. For comparison, the interactions of egg-grown infectious Sendai virus with the same cells were also examined. When noninfectious virus was adsorbed to the cells in the cold, the cell membranes become partially invaginated at the site of contact of adsorbed virions, but ferritin-conjugated antibodies did not penetrate into the areas of envelope-cell membrane association. This pattern of virus attachment was similar to that of infectious virus attachment. Upon subsequent incubation at 37 degrees C, most of the adsorbed noninfectious virions were taken into cytoplasmic vesicles and then degraded, although a few virions remained attached to the cell membrane. No evidence of fusion of envelopes of noninfectious virions was obtained. On the other hand, envelopes of infectious virions fused with the cell membrane, and the transferred viral antigens diffused on the cell surfaces and then decreased in number. 相似文献
126.
Nobuhiko Suzuki Yasuhisa Kunimi Seiji Uematsu Ken’ichi Kobayashi 《Population Ecology》1980,22(2):273-283
Summary The changes in spatial distribution pattern during larval stage of the fall webworm,Hyphantria cunea were quantitatively investigated in the field experimental populations.
The female adult deposits eggs as a cluster and the hatchlings make a compact colonial-web. In this period, the all-or-none
type mortality which is characteristic in gregarious insect species was occasionary recognized before spinning a compact colonial-web.
Once making a compact colonial-web, the larvae feed the leaves in the colonial-web up to about 5th instar. In this period,
the movement of larvae occurred due to the local food shortage in a colonial-web and the expansion of colonial-web. As the
larvae developed, the colonial-web was separated into several small groups. These larvae began to disperse about 5th instar.
In this period, the local food shortage seems to be an important trigger for the larval dispersal. The mean concentration
of larvae on leaves abruptly decreased, and finally the larvae became solitary at the 6th or 7th instars.
The dispersal process in later larval stage is not necessarily due to the complete food shortage. The dispersal prior to the
occurrence of food shortage may be a safety mechanism to protect the larvae from the food shortage. 相似文献
127.
Seiji Suzuki Hiroshi Oka Hiroko Yasuda Masahiro Ikeda Po Yuan Cheng Toshitsugu Oda 《Biochemical and biophysical research communications》1981,99(3):987-993
Isolated rat pancreatic islets, incubated in the presence of extracellular 32Pi to steady state 32P incorporation into cellular phosphopeptides, were exposed to glucose for 10 min. Glucose (16.7 mM) significantly stimulated the phosphorylation of six phosphoproteins with molecular weights of 15,000, 35,000, 49,000, 64,000, 93,000 and 138,000. Mannoheptulose (16.7 mM) markedly inhibited glucose-stimulated phosphorylation of these six phosphoproteins. This protein phosphorylation might be important in mediating glucose-stimulated insulin release. 相似文献
128.
Properties of crystalline L-ornithine: alpha-ketoglutarate delta-aminotransferase from Bacillus sphaericus.
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The distribution of bacterial L-ornithine: alpha-ketoglutarate delta-aminotransferase (L-ornithine:2-oxo-acid aminotransferase [EC 2.6.1.13]) was investigated, and Bacillus sphaericus (IFO 3525) was found to have the highest activity of the enzyme, which was inducibly formed by addition of L-ornithine or L-arginine to the medium. L-Ornithine:alpha-ketoglutarate delta-aminotransferase, purified to homogeneity and crystallized from B. sphaericus, had a molecular weight of about 80,000 and consisted of two subunits identical in molecular weight (41,000) and in amino-terminal residue (threonine). The enzyme exhibited absorption maxima at 278,343, and 425 nm and contained 1 mol of pyridoxal 5'-phosphate per mol of enzyme. The formyl group of pyridoxal 5'-phosphate was bound through an aldimine linkage to the epsilon-amino group of a lysine residue of the protein. The enzyme-bound pyridoxal 5'-phosphate, absorbing at 425 nm, was released by incubation with phenylhydrazine to yield the catalytically inactive form. The inactive enzyme, which was reactivated by addition of pyridoxal 5'-phosphate, still had a 343-nm peak and contained 1 mol of a vitamin B6 compound. The holoenzyme showed positive circular dichroic bands at 340 and 425 nm, whereas the inactive form had no band at 425 nm. The enzyme was highly specific for L-ornithine and alpha-ketoglutarate and catalyzed delta-transamination between them to produce L-glutamate and L-glutamate-gamma-semialdehyde, which as spontaneously converted to delta 1-pyrroline-5-carboxylate. The enzyme activity was significantly affected by nonsubstrate amino acids, amines, and carbonyl reagents. 相似文献
129.
A contractile ring and cortical changes found in the dividing Tetrahymena pyriformis 总被引:1,自引:0,他引:1
Tomoyoshi Yasuda Osamu Numata Kazuo Ohnishi Yoshio Watanabe 《Experimental cell research》1980,128(2):407-417
A contractile ring consisting mainly of microfilaments was found in the fission zone of dividing Tetrahymena pyriformis. Diameters of the microfilaments were widely distributed from 2.5 to 15 nm. Ring-associated structures such as lateral stripes, linkers and beads with siender tails were recognized. Lateral stripes arranged at regular intervals of about 84 nm on some parts of microfilament bundles were found in both tangential and transverse sections, suggesting that they correspond to bands fastening the contractile ring microfilaments. Linkers that connect individual lateral stripes to the epiplasmic layer were present. Beads or beads with slender tails were found to be arranged on some microfilaments.The results of the present paper also indicate that drastic morphological changes occur in the cortex of the fission zone, especially in the epiplasmic layer, accompanying contraction of the division furrow. The epiplasmic layer which was proved to be a compact filamentous network in this study has been known to exist at the periphery of cytoplasm in immediate contact with one of the cell surface membranes, the inner alveolar membrane; however, in the fission zone of the dividing ceil, it was frequently separated from the membrane and subsided into the cytoplasm. The subsided epiplasmic layer was then loosened and dispersed. The subsidence of the epipiasmic layer appears to be caused by the force generated by the contraction of the contractile ring and transmitted with the linkers to the epiplasmic layer. The changes observed in the epiplasmic layer are presumably indispensable for the rigid cortical layer contraction involved in cytokinesis of Tetrahymena. 相似文献
130.
A temperature-sensitive mutant of cultured mouse cells defective in chromosome condensation 总被引:6,自引:0,他引:6
A temperature-sensitive mutant, designated ts85, was isolated from a mouse mammary carcinoma cell line, FM3A. The ts85 cells grew at 33 °C (permissive temperature) with a doubling time of 18 h, which was almost the same as with wild-type cells, whereas the cell number scarcely increased at all at 39 °C (non-permissive temperature). When the ts85 cells were shifted from 33 to 39 °C, their DNA synthesis fell to below 1% of the initial value in 14 h. RNA or protein synthesis, however, was maintained at the initial levels for at least 14 h at 39 °C. Cytofluorometric analysis of asynchronous cultures and studies with synchronous cultures suggested that the bulk of the cells cultured at 39 °C for 12–18 h were arrested in late S and G2 phases. Electron microscopic observations revealed that chromatin was abnormally condensed into fragmented and compact forms, particularly around nucleoli, in about 80% of cells of an asynchronous culture incubated at 39 °C for 16 h. Cells in mitosis were not detected in such cultures and nuclear membrane and nucleoli were still intact. Such abnormal chromosome condensation was not observed in the ts85 cells at 33 °C or in wild-type cells at either temperature. Since these findings suggest that a ts gene product of ts85 cells is necessary for chromosome condensation, ts85 cells may represent a useful tool for establishing the mechanisms of chromosome condensation. The interrelationship between abnormal chromosome condensation and reduction in DNA synthesis of the ts85 cells is discussed. 相似文献