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排序方式: 共有1002条查询结果,搜索用时 15 毫秒
131.
Kawahara M Obata Y Sotomaru Y Shimozawa N Bao S Tsukadaira T Fukuda A Kono T 《Nature protocols》2008,3(2):197-209
A reliable nuclear transfer method was first reported in 1983; it provided definite evidence that parthenogenetic embryos are lethal at early postimplantation in mammals. Subsequently, nuclear transfer has been extensively used as an important and versatile tool for investigating embryo and somatic-cell cloning and nucleo-cytoplasmic interactions. Further development of this technique has enabled the generation of bimaternal embryos containing two haploid sets of maternal genomes from female germ cells of different origins. By using a 2-d nuclear transfer system for oocyte reconstruction, viable mice can be produced solely from maternal genomes, without the participation of the paternal genome. This oocyte reconstruction system, as described in this protocol, could provide valuable guidelines for exploring the potential endowments of gametes and for conferring novel properties to them. 相似文献
132.
133.
Cardiomyocytes (CMs) fuse with various cells including endothelial cells, cardiac fibroblasts (CFs). In addition, recent studies have shown that stem cells fuse spontaneously with cells remaining in the damaged tissues, and restore tissue functions after myocardial infarction. In this study, we investigated whether cultured cardiomyocytes fused with proliferative cardiac fibroblasts maintained the phenotype of functional myocytes by analyzing the spontaneous contraction rhythm after fusion with CFs lacking a beating capability. CMs and CFs cultured for 4 days in vitro were used in this study. The fusion of cultured CMs and CFs was achieved with polyethylene glycol (PEG) and hemagglutinating virus of Japan (HVJ). Analyses of CMs fused with CFs by using either PEG or HVJ to imitate spontaneous fusion in vivo demonstrated that CMs and CFs actually fused together and fused cells expressed lineage marker proteins of both CMs and CFs. In addition, fused cells reentered the G2-M phase of the cell cycle. Furthermore, fused cells retained the spontaneous contraction activity. The present study demonstrated that CMs fused with proliferative CFs showed the phenotype of both CMs and CFs and spontaneous rhythmic contraction. 相似文献
134.
BACKGROUND/AIMS: Phosphatases are involved in regulation of MAP kinase (MAPK). A431 cells migrate on collagen after EGF stimulation using MAPK. To clarify the involvement of PP2A in this MAPK-dependent migration, the expression of an isoform of the B regulatory subunit was inhibited. METHODS: An antisense sequence corresponding to Bbeta cDNA was transfected into A431 cells. Their migratory activity on collagen was examined using Transwell, and MAPK phosphorylation and phosphatase activity were measured, and the results were compared with those obtained with mock-transfected cells. RESULTS: Antisense-transfected cells showed less Bbeta protein and phosphatase activity than mock-transfected controls. Migration of antisense-transfected cells showed a low response to EGF. The response of MAPK phosphorylation of antisense-transfected cells to EGF stimulation and adhesion to collagen in the presence or absence of EGF were markedly decreased. Phosphatase activity of PP2A-Bbeta also did not respond to EGF, collagen or EGF plus collagen, and remained at low levels. CONCLUSION: These results suggested that PP2A-Bbeta promotes cell migration through the MAPK cascade. 相似文献
135.
136.
Yuping Li Tomohiro Nishimura Kiichiro Teruya Tei Maki Takaaki Komatsu Takeki Hamasaki Taichi Kashiwagi Shigeru Kabayama Sun-Yup Shim Yoshinori Katakura Kazuhiro Osada Takeshi Kawahara Kazumichi Otsubo Shinkatsu Morisawa Yoshitoki Ishii Zbigniew Gadek Sanetaka Shirahata 《Cytotechnology》2002,40(1-3):139-149
Reactive oxygen species (ROS) cause irreversible damage to biological macromolecules, resulting in many diseases. Reduced
water (RW) such as hydrogen-rich electrolyzed reduced water and natural reduced waters like Hita Tenryosui water in Japan
and Nordenau water in Germany that are known to improve various diseases, could protect a hamster pancreatic β cell line,
HIT-T15 from alloxan-induced cell damage. Alloxan, a diabetogenic compound, is used to induce type 1 diabetes mellitus in
animals. Its diabetogenic effect is exerted via the production of ROS. Alloxan-treated HIT-T15 cells exhibited lowered viability,
increased intracellular ROS levels, elevated cytosolic free Ca2+ concentration, DNA fragmentation, decreased intracellular ATP levels and lowering of glucose-stimulated release of insulin.
RW completely prevented the generation of alloxan-induced ROS, increase of cytosolic Ca2+ concentration, decrease of intracellular ATP level, and lowering of glucose-stimulated insulin release, and strongly blocked
DNA fragmentation, partially suppressing the lowering of viability of alloxan-treated cells. Intracellular ATP levels and
glucose-stimulated insulin secretion were increased by RW to 2–3.5 times and 2–4 times, respectively, suggesting that RW enhances
the glucose-sensitivity and glucose response of β-cells. The protective activity of RW was stable at 4 °C for over a month,
but was lost by autoclaving. These results suggest that RW protects pancreatic β-cells from alloxan-induced cell damage by
preventing alloxan-derived ROS generation. RW may be useful in preventing alloxan-induced type 1-diabetes mellitus.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
137.
Takeshi Kawahara Akira Ichikawa Yoshinori Katakura Kiichiro Teruya Takahisa Yoshida Masahiro Kikuchi Masanori Kamei Shuichi Hashizume Sanetaka Shirahata 《Cytotechnology》2001,36(1-3):171-177
Adult T cell leukemia (ATL) is a malignant disease characterized by tumorous proliferation of CD4+ T cells infected with retrovirus human T cell leukemia virus Type-I (HTLV-I) and concurs with an autoimmune disease and cancer
due to attenuated immune response. In this study, we established ATL patient derived B-cell line TM-1 producing cancer-specific
IgM antibodies, and further characterized its antigen specificity by establishing hybridomas fused with human-mouse origin
hetero-myeloma cell line RF-S1. We established three hybridoma cell lines termed 2E12, 3E9, and 3E10, which continuously secreted
human IgM antibodies. Immunohistochemical staining of formalin-fixed tissue section using antibodies secreted from these hybridomas
showed that these antibodies specifically recognized tumor sites of human colon adenocarcinomas. Antibody produced from hybridoma
3E9 bound to some of leukemic cell lines, but not to normal human PBL, which was evidenced by the flow cytometric analysis,
indicating that antibody produced from 3E9 recognizes cell surface antigen specifically expressed in the leukemic cells.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
138.
Background
The reactive oxygen-generating N ADPH ox idases (Noxes) function in a variety of biological roles, and can be broadly classified into those that are regulated by subunit interactions and those that are regulated by calcium. The prototypical subunit-regulated Nox, Nox2, is the membrane-associated catalytic subunit of the phagocyte NADPH-oxidase. Nox2 forms a heterodimer with the integral membrane protein, p22 phox, and this heterodimer binds to the regulatory subunits p47 phox, p67 phox, p40 phox and the small GTPase Rac, triggering superoxide generation. Nox-organizer protein 1 (NOXO1) and Nox-activator 1 (NOXA1), respective homologs of p47 phox and p67 phox, together with p22 phox and Rac, activate Nox1, a non-phagocytic homolog of Nox2. NOXO1 and p22 phox also regulate Nox3, whereas Nox4 requires only p22 phox. In this study, we have assembled and analyzed amino acid sequences of Nox regulatory subunit orthologs from vertebrates, a urochordate, an echinoderm, a mollusc, a cnidarian, a choanoflagellate, fungi and a slime mold amoeba to investigate the evolutionary history of these subunits. 相似文献139.
140.
Takeshi Wada Yuichi Sato Fumio Honda Shun-Ichi Kawahara Akira Mochizuki Mitsuo Sekine 《Nucleosides, nucleotides & nucleic acids》2013,32(6-7):1225-1226
Abstract Oligodexyribonucleotides were synthesized by using N-unprotected H-phosphonate monomers and a phosphonium-type of new condensing reagent. In the present H-phosphonate approach, N-sulfonyloxaziridine derivatives were successfully employed as new reagents for oxidation of the H-phosphonate linkages in the presence of silylating reagents. 相似文献