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排序方式: 共有1147条查询结果,搜索用时 15 毫秒
1.
Tanaka Osamu; Nasu Yutaka; Sonoyama Akiko; Maehara Yasuko; Kobayashi Takako; Nawafune Hidemi; Kugimoto Mamoru 《Plant & cell physiology》1987,28(4):697-702
The flowering of Lemna paucicostata 6746 grown on 14-h photoperiodwas enhanced by the addition of high concentrations of ironto the medium, which also increased the endogenous iron concentration.The addition of asparagine, aspartate, glutamate, -alanine,glycine or serine to the medium also increased the endogenousiron level, resulting in the promotion of flowering. In contrast,the addition of cysteine, cystine, glutamine, arginine, threonineor phenylalanine lowered the endogenous iron level, resultingin the inhibition of flowering. Glycine and asparagine added to the medium during an inductive96-h dark period did not promote iron uptake and had no effecton flowering, but when added during the subsequent 120-h lightperiod, they promoted both iron uptake and flowering response.The increase in the endogenous iron level seems to favor floraldevelopment rather than induction of photoperiodic floweringof Lemna paucicostata 6746. (Received September 8, 1986; Accepted March 31, 1987) 相似文献
2.
Tadao Arinami Takeki Hirano Kimiko Kobayashi Yasuko Yamanouchi Hideo Hamaguchi 《Human genetics》1990,85(1):39-40
Summary The XmnI genotype at the apolipoprotein A-I locus was heterozygous in a boy with partial deletion of the long arm of chromosome 11, del(11)(q23.3qter). The apolipoprotein A-I gene, previously assigned to chromosome region 11q23q24, has been more specifically localized to 11q23 by excluding the region 11q24qter. 相似文献
3.
Prof. Katsuko Kataoka Junko Miura Yasuko Takeoka Yoshisuke Kusumoto Noboru Yanaihara 《Cell and tissue research》1985,239(3):531-535
Summary Ontogenesis of gastrin cells was studied in the pyloroduodenal mucosa of the mouse using anti-human G17 serum, R-1301, and anti-human G34(1–15) serum, R-2703. R-1301-immunostained cells first appeared in the pyloric mucosa of 14-day-old fetuses. Cells stained with both R-1301 and R-2703 appeared immediately after birth, and gradually increased in number to the adult level. Most R-1301-reactive cells were also reactive to R-2703, whereas some cells that reacted with R-1301 exhibited very weak or no reaction with R-2703. The discrepancy between these two immunoreactivities is discussed.In the duodenum, a considerable number of R-1301-reactive cells were present from the perinatal stage and through out adult development. A few R-2703-reactive cells were seen in the duodenum of young mice but not of the adult. 相似文献
4.
Yasuko Kobayashi Candace J. S. Hassall Professor Geoffrey Burnstock 《Cell and tissue research》1986,244(3):605-612
Summary The present study describes the ultrastructure of non-neuronal cells and their interrelationships with intracardiac neurones present in cultures dissociated atria and interatrial septum from newborn guinea-pig. When compared with the in situ preparation, most of these features in culture were similar to those observed in situ, but some differences were also apparent. Both mature and immature Schwann cells were observed in culture, and as in situ, the latter were closely associated with intracardiac neurones, whilst the former were more widely separated. The ultrastructure of satellite cells was more variable in culture than in situ: three general types were distinguished on the basis of their 10-nm filament content. This variation could be due to conditions of culture. Interstitial cells were present in culture and closely resembled those described in situ, although there was less space between cultured interstitial cells and their associated cells. Many fibroblasts, some myoblasts and a few mast cells were also found in the culture preparations. 相似文献
5.
Chloroplasts consist of six morphologically distinct compartments. Each compartment has a specific set of polypeptides that perform distinct biochemical functions. We report here the identification of a membrane-associated protein with a novel localization. This protein was synthesized as a 37 kDa precursor and was processed to a mature protein of 30 kDa after being imported into isolated pea chloroplasts. Fractionation of chloroplasts showed that the 30 kDa mature protein was associated with both of the envelope membranes as well as with thylakoid membranes. Immunocyto-chemical localization of the 30 kDa protein revealed that the protein occurred in clusters in the vicinity of both the envelope and the thylakoid. Possible functions of this 30 kDa protein, inferred from its novel localization pattern, are discussed.Abbreviations CAB
light-harvesting chlorophyll a/b-binding protein of photosystem II
- prCAB
precursor protein to CAB
- SS
small subunit of ribulose-1,5-bisphosphate carboxylase
- prSS
precursor protein to SS
- RCF
relative centrifugation force 相似文献
6.
The role of the molybdenum cofactor (Mo cofactor) in the translocationof dimethyl sulfoxide (DMSO) reductase to the periplasmic spacewas studied in vivo by isolating chlorate-resistant mutantsof Rhodobacter sphaeroides f. sp. denitrificans. More than 50%of the chlorate-resistant mutants isolated were defective inthe biosynthesis of the Mo cofactor and all of these mutantsaccumulated the precursor form of the enzyme. About 45% of themutants contained the same level of Mo cofactor as the parentstrain and exhibited normal levels of DMSO reductase and nitratereductase activities when chlorate was absent from the medium,but the activities of these enzymes were depressed when chloratewas present. Much of the accumulated precursor form of the enzymein a Mo cofactor-deficient mutant was bound to the cytoplasmicmembrane and was sensitive to treatment with proteinase K fromthe periplasmic side of the membrane, an indication that theprecursor was exposed on the periplasmic surface of the membrane.The precursor accumulated on the membrane of the parent strainwhen molybdate was removed from the medium or upon additionof tungstate and this precursor was also sensitive to the treatmentwith proteinase K from the periplasmic side. These results suggestthat the Mo cofactor is necessary for proteolytic processingof the precursor to the mature enzyme on the periplasmic sideof the membrane, whereas binding of the precursor to the membraneand translocation across it can occur in the absence of thecofactor. Almost all of the Mo cofactor available for directreconstitution in vitro of nitrate reductase activity from thenit-l mutant of Neurospora crassa was present in the cytoplasmicfractions. (Received December 11, 1991; Accepted March 25, 1992) 相似文献
7.
Prostaglandin D2 strongly inhibited growth of cultured mastocytoma P-815, 2-E-6 cells, which were established and cloned from mouse mast tumor cells. The inhibition was dose-dependent (IC50 = 2.09 × 10−5 M). Prostaglandin D2 also inhibited the DNA synthesizing activity of the cells dose-dependently. We next measured the activities of endogenous DNA polymerases extracted from untreated and prostaglandin D2-treated cells. Prostaglandin D2 pretreatment reduced DNA polymerase α activity by 52%. The sedimentation coefficients of the enzymes from untreated and prostaglandin D2-treated cells were the same suggesting there was no gross change in the size of the enzyme. Prostaglandin D2 pretreatment of the cells reduced endogenous DNA polymerase β activity to 68% of the control value; the sedimentation coefficients of the enzymes from treated and untreated cells were both 3.5 S. Interestingly, prostaglandin D2 had no direct inhibitory effect on the activity of either DNA polymerase α or β. Our results indicate that the activities of DNA polymerase α and β are lower in prostaglandin D2-treated mastocytoma cells. This finding account for the lower level of DNA synthesis in these cells. 相似文献
8.
Neuromuscular junctions were formedin vitro between rat spinal cord explants and myotubes. At various intervals after the spinal cord explants were added to the myotube culture (7 hr to 15 days of coculture), the presence of functional neuromuscular junctions was determined by recording miniature endplate potentials (mepps) from the myotubes contacted by a few neurites. Electron microscopical studies were conducted on identified myotubes in which mepps were recorded. Mepps were already found as early as 7 hr after coculture. The fine structure of these newly formed neuromuscular junctions was simple. No synaptic specializations were observed except the presence of a small number of synaptic vesicles in the nerve. The neuromuscular junctions differentiated during the coculture period. Synaptic vesicles formed a cluster at the prejunctional membrane with a localized density in the middle. Basal lamina started to form in 4-day-old cocultures and became continuous in cocultures of 10 days or longer. Clear postjunctional foldings were observed in 15-day-old cocultures. Higher mepp frequencies were correlated with more advanced ultrastructure. 相似文献
9.
Several strains of mice are known to develop spontaneous autoimmune diseases like lupus erythematosus and they show various immunological abnormalities as well. Despite different genetic backgrounds, they manifest various immunological abnormalities in common, e.g., polyclonal B-cell activation (PBA) and resistance to tolerance induction. To elucidate mechanisms of the development of autoimmunity, tolerance inducibility was examined in autoimmune and normal mice using trinitrophenylated carboxymethyl cellulose (TNP-CMC) as tolerogen which is known to induce TNP-specific B-cell tolerance without the participation of T cells. NZB and MRL/Mp-lpr/lpr mice were used as autoimmune mice and C57BL/6, BALB/c, and MRL/Mp-+/+ mice as nonautoimmune mice. When TNP-CMC-injected mice were challenged with T-independent antigens, all of the mice tested were shown to be tolerant. In contrast, when TNP-CMC-injected mice were challenged with T-dependent antigen and secondary IgG responses were assessed, autoimmune mice showed rather hyperreactivity, while nonautoimmune mice showed hyporesponsiveness. Cyclophosphamide improved this defective tolerance inducibility. By the solid-phase radioimmunoassay it was revealed that average affinity of serum anti-TNP antibodies produced in TNP-CMC-injected mice was low. Such low affinity antibodies were produced in large amount in autoimmune mice. Hence, it was suggested that B-cell clones destined to produce low affinity IgG antibodies were responsible for the resistance to tolerance induction and such clones were expanding in autoimmune mice. 相似文献
10.
Yasuko Mizuno Atsushi Ichikawa Kenkichi Tomita 《Prostaglandins & other lipid mediators》1983,26(5):785-795
The effect of 7-fluoro proscyclilin (PGI2-F), a chemically stable analogue of prostacyclin, on cAMP accumulation in and [3H]PGE binding to mastocytoma P-815 cells was compared with those of the Na salt and methyl ester of prostacyclin (PGI2Na or PGI2Me), which are rapidly inactivated in aqueous solution or metabolized in the tissue.PGIF was as effective as PGI2Me, and slightly less effective than PGI2Na in stimulating cAMP accumulation in mastocytoma cells and rabbit platelets. PGI2F was also more stable than PGI2Me or PGI2Na, and retained its original cAMP elevating activity even after incubation with or without cells for 4 h at 37°C. Cells which had been exposed to PGI2F and then washed free of unbound reagent continued to produced cAMP for more than 3 h. PGI2F was also as effective as PGE1 or PGE2 in displacing [3H]PGE2 bound to the cells. Non-competitive inhibition by PGI2F or PGI2Me of [3H]PGE2 binding to the cells, with apparent Kis of 1.29 μM and 1.13 μM, respectively, indicates the presence of different receptors for PGE2 and for PGI2F or PGI2Me in mastocytoma P-815 cells. 相似文献