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排序方式: 共有1046条查询结果,搜索用时 15 毫秒
1.
Satoko Iwahori Daisuke Kohmon Junya Kobayashi Yuhei Tani Takashi Yugawa Kenshi Komatsu 《Cell cycle (Georgetown, Tex.)》2014,13(3):471-481
Ataxia-telangiectasia mutated (ATM) plays crucial roles in DNA damage responses, especially with regard to DNA double-strand breaks (DSBs). However, it appears that ATM can be activated not only by DSB, but also by some changes in chromatin architecture, suggesting potential ATM function in cell cycle control. Here, we found that ATM is involved in timely degradation of Cdt1, a critical replication licensing factor, during the unperturbed S phase. At least in certain cell types, degradation of p27Kip1 was also impaired by ATM inhibition. The novel ATM function for Cdt1 regulation was dependent on its kinase activity and NBS1. Indeed, we found that ATM is moderately phosphorylated at Ser1981 during the S phase. ATM silencing induced partial reduction in levels of Skp2, a component of SCFSkp2 ubiquitin ligase that controls Cdt1 degradation. Furthermore, Skp2 silencing resulted in Cdt1 stabilization like ATM inhibition. In addition, as reported previously, ATM silencing partially prevented Akt phosphorylation at Ser473, indicative of its activation, and Akt inhibition led to modest stabilization of Cdt1. Therefore, the ATM-Akt-SCFSkp2 pathway may partly contribute to the novel ATM function. Finally, ATM inhibition rendered cells hypersensitive to induction of re-replication, indicating importance for maintenance of genome stability. 相似文献
2.
Eiji Kumazawa Akiko Tohgo Tsunehiko Soga Tsuneo Kusama Yasuaki Osada 《Cancer immunology, immunotherapy : CII》1992,35(5):307-314
Summary The antitumor effect of a synthetic lipid A analogue, DT-5461, was investigated using syngeneic tumor models in mice. Intravenous injection of DT-5461 into mice transplanted with solid tumors of MethA fibrosarcoma, MH134 hepatoma, MM46 mammary carcinoma, Lewis lung carcinoma (3LL), and colon adenocarcinomas 26 and 38 resulted in significant reductions in the weight of all tumors except Colon 26, with marked hemorrhagic necrosis of tumor tissues. Efficacy was almost equal to that of anEscherichia coli-type synthetic lipid A (compound 506), and also to those of some chemotherapeutics including Adriamycin, mitomycin C, fluorouracil and cisplatin. Furthermore, DT-5461 was more effective than other immunotherapeutics, including picibanil (OK-432) and lentinan. However, its antitumor effects were inferior to those of Adriamycin or OK-432 against the malignant ascites caused by intraperitoneal inoculation with MethA or with MH134 cells; life span was not prolonged by either intraperitoneal or intravenous administration. In addition, although DT-5461 showed direct inhibitory effects on the in vitro growth of MethA or MH134, these were much weaker than those of Adriamycin. These findings clearly indicated that DT-5461 with systemic administration is a highly effective antitumor agent on solid tumors, and suggest that the antitumor effect of DT-5461 with potent necrotizing activity might derive from indirect mechanisms related to the activation of host immune systems and not to the weak direct cytotoxicity. 相似文献
3.
Soichi Kojima Wakako Soga Hiromi Hagiwara Motoyuki Shimonaka Yuji Saito Yuji Inada 《Bioscience reports》1986,6(12):1029-1033
We have succeeded in corroborating the enhancing effect of vitamin A, vitamin C, sitosterol and fucosterol on the fibrinolytic activity of endothelial cells. The assay system consisted of anin situ dissolution of a fibrin layer coated onto a culture dish, over which endothelial cells were grown in a culture medium containing 10 % serum. The dissolution was enhanced by the addition of these vitamins and phytosterols to the culture medium.To whom correspondence should be addressed. 相似文献
4.
Yuichi Murayama Ryozaburo Mukai Tetsutaro Sata Satoko Matsunaga Atsuo Noguchi Yasuhiro Yoshikawa 《Microbiology and immunology》1996,40(6):467-471
In contrast to the case of peripheral T cells, the surface expression of CD20 antigen and the expression of CD20 mRNA in monkey lymph node (LN) T cells underwent a noticeable increase when they were cultured with mitogen and interleukin-2 (IL-2). To confirm in vivo regulation of CD20 expression during the activation of LN T cells, we examined LNs derived from monkeys experimentally inoculated with simian immunodeficiency virus (SIV). Significant expression of CD20 antigen was detected in the T cells of the LNs at the stage of lymphadenopathy. These findings suggest that lymphocyte activation in the LNs induced expression of the CD20 molecule in some T cells. 相似文献
5.
Summary
Pseudomonas oleovorans grew well and synthesized copolyesters of 3-hydroxyalkanoates and 3-hydroxy--fluoroalkanoates in the mineral medium containing 1-fluorononane and sodium gluconate. The content of fluorinated units in copolyesters could be controlled from 0 to 40 mol%. The copolyesters were shown to have a random sequence distribution of different monomeric units by analysis of the13C NMR spectra. The melting temperatures of copolyesters were 52–58°C, and the enthalpy of fusion decreased with the content of fluorinated units. 相似文献
6.
Shintani Masuro Minaguchi Kiyoshi Isemura Satoko Saitoh Eiichi Sanada Kazuo Semba Toshihiko 《Human genetics》1994,94(1):45-49
A new genetic polymorphism of cystatin SA has been identified in human submandibular-sublingual saliva by means of basic gel electrophoresis and immunoblotting with anti-cystatin S. Two proteins, SA1 and SA2, are given by two alleles of CST2, viz., CST2*1 and CST*2. Inheritance is controlled by two codominant alleles at an autosomal locus. This hypothesis is supported by studies of 16 families 32 children. Gene frequencies for CST2*1 and CST2*2 are 0.935 and 0.065, respectively (n = 341). Eighteen amino acids determined among 20 N-terminal residues of cystatin SA2 are identical with the sequence encoded by CST2. Three forms of cystatin S (mono-phosphorylated cystatin S, di-phosphorylated cystatin S, and non-phosphorelated cystatin S) are present in the 341 saliva samples tested. 相似文献
7.
Gravity resistance, another graviresponse in plants--function of anti-gravitational polysaccharides]
The involvement of anti-gravitational polysaccharides in gravity resistance, one of two major gravity responses in plants, was discussed. In dicotyledons, xyloglucans are the only cell wall polysaccharides, whose level, molecular size, and metabolic turnover were modified under both hypergravity and microgravity conditions, suggesting that xyloglucans act as anti-gravitational polysaccharides. In monocotyledonous Poaceae, (1-->3),(1-->4)-beta glucans, instead of xyloglucans, were shown to play a role as anti-gravitational polysaccharides. These polysaccharides are also involved in plant responses to other environmental factors, such as light and temperature, and to some phytohormones, such as auxin and ethylene. Thus, the type of anti-gravitational polysaccharides is different between dicotyledons and Poaceae, but such polysaccharides are universally involved in plant responses to environmental and hormonal signals. In gravity resistance, the gravity signal may be received by the plasma membrane mechanoreceptors, transformed and transduced within each cell, and then may modify the processes of synthesis and secretion of the anti-gravitational polysaccharides and the cell wall enzymes responsible for their degradation, as well as the apoplastic pH, leading to the cell wall reinforcement. A series of events inducing gravity resistance are quite independent of those leading to gravitropism. 相似文献
8.
Chloroplast division in Nannochloris bacillaris Naumann (Chlorophyta) was examined by electron microscopy after preparation of samples by freeze-substitution. A pair of belts appeared on the surface of the outer and inner envelope membranes at the middle of the chloroplast. These belts seemed to be constructed of thin fibrils that run parallel to the longitudinal direction of the belts. The outer fibrillar belt increased in width as the constriction of the chloroplast advanced. It appears that the fibrillar belt is the division apparatus of the chloroplast. It encircles the chloroplast and finally divides the chloroplast in two as the diameter of the belt decreases. 相似文献
9.
Phylogeny of symbiotic methanogens in the gut of the termite Reticulitermes speratus 总被引:3,自引:0,他引:3
Abstract The phylogeny of a symbiotic methanogen inhabiting the gut of a lower termite, Reticulitermes speratus , was analysed without cultivation. The small subunit ribosomal RNA gene (ssrDNA) and a 640-bp portion of the gene encoding subunit A of methyl coenzyme M reductase ( mcrA ) were amplified from a mixed-population DNA of the termite gut by polymerase chain reaction and cloned. The nucleotide sequence of the ssrDNA and the predicted amino acid sequence of the mcrA product were compared with those of the known methanogens. Both comparisons indicated that the termite symbiotic methanogen belonged to the order Methanobacteriales but was distinct from the known members of this order. 相似文献
10.
DNA sequence polymorphisms in transthyretin (TTR) genes were investigated by single-strand conformation polymorphism (SSCP) analysis of polymerase chain reaction products. The amplified DNA fragments that encode each exon of the normal TTR gene showed two bands, representing the two complementary single strands of DNA. In one patient with amyloid polyneuropathy, the exon 3 DNA showed a unique, aberrant migration pattern. Direct sequencing analysis of the amplified exon 3 revealed a single base change (G-to-T), resulting in a novel amino acid substitution (Ser-50----Ile). We also present the SSCP patterns for five known Japanese TTR variants. 相似文献