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51.
Simultaneous induction of Pb-metallothionein-like protein and Zn-thionein in the liver of rats given lead acetate. 总被引:1,自引:0,他引:1
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Administration of a sublethal dose of lead acetate to rats induced the simultaneous synthesis of a Pb-metallothionein (Pb-MT)-like protein (Pb-BP) and Zn-thionein (Zn-BP) in the liver. The Pb-BP had an apparent molecule mass of 6900 Da and seemed to bind preferentially to lead in the liver cytosol. The Zn-BP was identified by comparison of the Mr, elution profiles from Sephadex G-75 and DEAE-Sephadex A-25 columns, and polyacrylamide-gel-electrophoretic mobility, with those of rat liver Zn-MT-II. The Pb-BP accumulated in the liver to a maximum 6 h after the intraperitoneal injection of lead acetate and accounted for about 60% of the lead in the liver cytosol at this stage. However, after that, it gradually decreased in the liver, until it was close to the basal amount 24 h after the induction. In contrast, the amount of Zn-MT increased gradually, reached a maximum 12 h after the administration of lead acetate and maintained a constant value until at least 24 h after the induction. Amino acid analysis of the Pb-BP indicated that it contained about 28% half-cysteine. These results strongly suggest that lead acetate induces the synthesis of Pb-MT as well as Zn-MT in rat liver. 相似文献
52.
K Akashi M Harada T Shibuya K Fukagawa N Kimura K Sagawa Y Yoshikai T Teshima M Kikuchi Y Niho 《Journal of cellular physiology》1991,148(3):446-456
We investigated the origin of leukemic progenitors in a case of the simultaneous occurrence of myelomonocytic leukemia and multiple myeloma (IgG-kappa). At presentation, myeloperoxidase and nonspecific esterase-positive myelomonocytic cells had proliferated up to 12.2 x 10(9)/liter in the peripheral blood. Bone marrow cell differentials revealed the coexistence of myelomonocytic cells (30%) and atypical plasmacytoid cells (26%). Myelomonocytic cells in peripheral blood expressed both myeloid antigens (CD11b, CD13, CD14, CD15, CD33) and T/B-lymphoid antigens (CD2, CD4, CD5, CD7, CD10, PCA-1). Bone marrow mononuclear cells (BMMC) could be divided into PCA-1 strongly positive and PCA-1 weakly positive populations, which were considered to represent myeloma cells and myelomonocytic cells, respectively; the former were CD2-positive (CD2+), CD14-, and CD15-, whereas the latter were CD2+, CD14+, and CD15+. Immunohistochemical analysis revealed that, in addition to plasmacytoid cells, a minority of myelomonocytic cells showed a positive reaction for IgG staining, and production of IgG was observed in the culture supernatant of CD14+ myelomonocytic cells in peripheral blood. Southern blot analysis revealed the presence of two identical rearrangement bands of immunoglobulin heavy chain gene in both BMMC containing myeloma cells and myelomonocytic cells and CD14+ myelomonocytic cells in peripheral blood. In a long-term methylcellulose assay, peripheral blood mononuclear cells produced large compact colonies consisting of macrophages and IgG+ plasmacytoid cells (M phi/P colonies), while BMMC produced a different type of colonies consisting of CD14+ myelomonoblasts, macrophages, and IgG+ plasma cells (Mb/M phi/P colonies) in addition to M phi/P colonies. Recloning experiments showed that primary Mb/M phi/P colonies gave rise to both secondary M phi/P and Mb/M phi/P colonies. These observations strongly suggest that common leukemic progenitors provide both myeloma and myelomonocytic leukemia cells, and the mechanism of "lineage infidelity" is probably involved in the development of their "bilineal" differentiation. 相似文献
53.
The phosphatidylcholine-hydrolyzing phospholipase C, so-called "phospholipase C" (PLC), was isolated from the culture of Bacillus cereus strain IAM 1208. The amino-acid composition and partial N-terminal sequence of the purified enzyme were in good agreement with those expected from the nucleotide sequence for a PLC of strain ATCC 10987 [Johansen et al. (1988) Gene 65, 293-304]. The chain-length dependence of kinetic parameters for the PLC-catalyzed hydrolysis of monodispersed short-chain phosphatidylcholines (diCNPC, N = 3-6) was studied by a pH-stat assay method at 25 degrees C, pH 8.0, and ionic strength 0.2 in the presence of saturating amounts of Zn2+ (0.1 mM). The result was compared with those for snake venom phospholipases A2 [Teshima et al. (1989) J. Biochem. 106, 518-527]. It was found that the interaction of the PLC with the head group of the substrate molecule is very important for the binding. The pH dependences of kinetic parameters for the hydrolysis of monodispersed diC5PC and mixed micelles of diC16PC with Triton X-100 were also studied under the same conditions. An ionizable group, whose pK value is perturbed from 7.77 to 8.30 by substrate binding, was found to be essential to the catalysis. This group was tentatively assigned to His 14 on the basis of the results on X-ray crystallographic and chemical modification studies [Hough et al. (1989) Nature 338, 357-360 and Little (1977) Biochem. J. 167, 399-404].(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
54.
Daisuke Teshima Kayo Ikeda Motoyoshi Satake Toshinobu Aoyama Koichiro Shimomura 《Plant cell reports》1988,7(4):278-280
Callus and adventitious roots were induced on leaf segments from shoot culture of Cephaelis ipecacuanha A. Richard on Murashige-Skoog medium containing 2,4-dichlorophenoxyacetic acid, indole-3-acetic acid, 1-naphthaleneacetic acid and kinetin. The contents of emetic alkaloids in calli, roots and root suspension cultures were quantified by HPLC. Roots cultured in solid and liquid Murashige-Skoog media yielded emetine and cephaeline. The amount of the two alkaloids in the root suspension culture was very similar to that of roots from ipecac mother plant grown in a greenhouse. In contrast, calli subcultured on Murashige-Skoog media containing combinations of 2,4-dichlorophenoxyacetic acid and kinetin produced only trace amounts of emetic alkaloids.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- IAA
indole-3-acetic acid
- NAA
l-naphthaleneacetic acid
- Kin
kinetin
- MS
Murashige-Skoog
- EM
emetine
- CP
cephaeline
- DW
dry weight. 相似文献
55.
A Tari K Sumii M Yoshihara H Ohgoshi H Teshima I Fukuhara K Haruma G Kajiyama K Tanaka A Miyoshi 《Biochemical and biophysical research communications》1987,147(3):1162-1169
Cisapride is a gastrointestinal prokinetic agent reported to be devoid of direct cholinergic effect from the myenteric plexus of the gut. The effect of cisapride (0.125, 0.5, 2mg/kg, i.p.) on the concentration beta-endorphin and substance P in rat gastrointestinal tract was studied. beta-Endorphinlike immunoreactivity contents were significantly increased in both mucosal and muscular layers of the entire gastrointestinal tract (from gastric body to rectum) of the rats treated with 2 mg/kg of cisapride. beta-Endorphinlike immunoreactivity contents were also increased in a part of the gastrointestinal tract of the rats treated with 0.125 or 0.5 mg/kg of cisapride. Substance P like immunoreactivity contents were significantly decreased in muscular layers of the rectosigmoid colon of the rats treated with 2 mg/kg of cisapride. This study suggests that the prokinetic effects of cisapride may relate to the contents of beta-endorphinlike immunoreactivity and substance P like immunoreactivity in gastrointestinal tract. 相似文献
56.
Aamir Ahmad Shadan Ali Alia Ahmed Azfur S. Ali Avraham Raz Wael A. Sakr KM Wahidur Rahman 《PloS one》2013,8(1)
Herceptin failure is a major clinical problem in breast cancer. A subset of breast cancer patients with high HER-2/neu levels eventually experience metastatic disease progression when treated with Herceptin as a single agent. Mechanistic details of development of this aggressive disease are not clear. Therefore, there is a dire need to better understand the mechanisms by which drug resistance develops and to design new combined treatments that benefit patients with aggressive breast cancer and have minimal toxicity. We hypothesized that 3, 3′-diindolylmethane (DIM), a non-toxic agent can be combined with Herceptin to treat breast cancers with high levels of HER-2/neu. Here, we evaluated the effects of Herceptin alone and in combination with DIM on cell viability, apoptosis and clonogenic assays in SKBR3 (HER-2/neu-expressing) and MDA-MB-468 (HER-2/neu negative) breast cancer cells. We found that DIM could enhance the effectiveness of Herceptin by significantly reducing cell viability, which was associated with apoptosis-induction and significant inhibition of colony formation, compared with single agent treatment. These results were consistent with the down-regulation of Akt and NF-kB p65. Mechanistic investigations revealed a significant upregulation of miR-200 and reduction of FoxM1 expression in DIM and Herceptin-treated breast cancer cells. We, therefore, transfected cells with pre-miR-200 or silenced FoxM1 in these cells for understanding the molecular mechanism involved. These results provide experimental evidence, for the first time, that DIM plus Herceptin therapy could be translated to the clinic as a therapeutic modality to improve treatment outcome of patients with breast cancer, particularly for the patients whose tumors express high levels of HER-2/neu. 相似文献
57.
A C 26 -sterol in the clam, Tapes philippinarum 总被引:1,自引:0,他引:1
58.
The Auxin-Binding Protein 1 (ABP1) was identified over 30 years ago thanks to it''s high affinity for active auxins. ABP1 plays an essential role in plant life yet to this day, its function remains ‘enigmatic.’ A recent study by our laboratory shows that ABP1 is critical for regulation of the cell cycle, acting both in G1 and at the G2/M transition. We showed that ABP1 is likely to mediate the permissive auxin signal for entry into the cell cycle. These data were obtained by studying a conditional functional knock-out of ABP1 generated by cellular immunization in the model tobacco cell line, Bright Yellow 2.Key Words: auxin responses, auxin-binding protein 1, immunomodulation, cellular immunisation 相似文献
59.
60.
Luong Cong Thuc Yasushi Teshima Naohiko Takahashi Yasuko Nagano-Torigoe Kaori Ezaki Kunio Yufu Mikiko Nakagawa Masahide Hara Tetsunori Saikawa 《Apoptosis : an international journal on programmed cell death》2010,15(6):669-678
Reactive oxygen species (ROS) are important intracellular signaling molecules and are implicated in cardioprotective pathways
including ischemic preconditioning. Statins have been shown to have cardioprotective effects against ischemia/reperfusion
injury, however, the precise mechanisms remain to be elucidated. We hypothesized that ROS-mediated signaling cascade may be
involved in pravastatin-induced cardioprotection. Cultured rat cardiomyocytes were exposed to H2O2 for 30 min to induce cell injury. Pravastatin significantly suppressed H2O2-induced cell death evaluated by propidium iodide staining and the MTT assay. Incubation with pravastatin activated catalase,
and prevented a ROS burst induced by H2O2, which preserved mitochondrial membrane potential. Protective effects were induced very rapidly within 10 min, which was
concordant with the up-regulation of phosphorylated ERK1/2. L-NAME, 5HD, N-acetylcysteine (NAC) and staurosporine inhibited ERK1/2 phosphorylation and also reduced pravastatin-induced cardioprotection,
suggesting NO, mitochondrial KATP (mitoKATP) channels, ROS and PKC should be involved in the cardioprotective signaling. We also demonstrated that pravastatin moderately
up-regulated ROS generation in a 5HD-inhibitable manner. In isolated perfused rat heart experiments, pravastatin administered
10 min prior to no-flow global ischemia significantly improved left ventricular functional recovery, and also reduced infarct
size, which were attenuated by the treatment with NAC, 5HD, L-NAME or staurosporine. Administration of pravastatin from the
beginning of reperfusion also conferred cardioprotection. Pravastatin protected the cardiomyocytes against oxidative stress
by preventing the ROS burst and preserving mitochondrial function. Moderately up-regulated ROS production by mitoKATP channels opening is involved in the pro-survival signaling cascade activated by pravastatin. 相似文献