共查询到20条相似文献,搜索用时 31 毫秒
1.
《Journal of receptor and signal transduction research》2013,33(5):699-712
AbstractA specific membrane-binding of an estradiol metabolite, the catecholestrogen (CE) 2 hydroxyestrone (2OH-E1), was demonstrated in two receptor-positive (MCF7 and VHB1) and one receptor-negative (MDA-MB-231) human mammary carcinoma cell lines. The three cell lines were found to be able to synthesise and inactivate CE. Solubilization of membrane bound CE results in a high molecular weight component whose specificity differs from that of the classical estrogen receptor. Apparent dissociation constants were 6-10. 10?9 M and binding capacities were higher in the receptor positive cell lines than in the receptor-negative one. Since CE are susceptible to rapid degradation, the presence of such a site may be relevant in the protection and concentration of 2OH-E1 which has been shown to have “in vitro” anti-estrogenic properties in MCF7 breast tumor cells. 相似文献
2.
The growth of the SC-115 mammary carcinoma in mice is androgen dependent. Estrogens antagonize the androgen effect. The high affinity binding of androgens and estrogens has been studied in soluble extracts of the tumor, of primary culture cells and clone MI1 cells.Results indicate that two distinct specific steroid hormone-binding sites (termed ‘receptors’) are found in all cytosol fractions. The androgen-receptor (A) binds testosterone, androstanolone, cyproterone (an anti-androgen), progesterone and estradiol, but only very weakly non-steroidal diethylstilbestrol. The estrogen-receptor (E) binds estrogenic substances such as estradiol and diethylstilbestrol, but no androgen. The apparent KD, eq for A and E receptors of [3H]androstanolone and [3H]estradiol respectively, is identical (-0.5-1 nM at 4 °C). The affinity of estradiol for the A-receptor, when measured against [3H]androstanolone binding, indicates a Ki = 17.5 nM. The concentration of binding sites is of the order of 0.1 pmole/mg protein (somewhat higher for A than for E receptor) in MI1 cell cytosol. Studies by ultracentrifugation through glycerol-Tris gradients (low salt medium) reveal the macromolecular nature of the cytosol A and E receptors (7–7.5 S). Evidence is presented of the transfer of the A and the E receptors to nuclei after incubation of tumor slices as well as of clone MI1 cells with the corresponding hormones.Experiments suggest that the two different binding sites are present on two separated macromolecular moieties. After incubation at 37 °C of tumor slices with 10–20 nM [3H]testosterone, or with 10 nM [3H]estradiol, the corresponding radioactive hormone-receptor complexes are, as expected, found in the nuclear KCl extracts. In parallel experiments, where slices are incubated with non-radioactive hormones at the same concentration and the nuclear KCl extracts subsequently treated by radioactive steroids, no available androgen-binding sites are found in the nuclei after exposure to estradiol, nor estrogen-binding sites after exposure to testosterone.Therefore, in the same cell, two receptors are present which bind androgens and estrogens with high affinity, and one given hormone (estradiol) can be specifically bound (with different affinities) by two different receptors which, however, discriminate a synthetic analog (diethylstilbestrol). The data may give some molecular background for interpreting responses to the same hormone which may differ at various concentrations, for studying effects of analogs, and for analysing the control of tumor growth by antagonistic steroids. 相似文献
3.
Benjamin J. Danzo Vathsala Krishnamurthy Barbara C. Eller 《Biochimica et Biophysica Acta (BBA)/General Subjects》1977,500(2):310-321
Macromolecular binding components for [3H]estradiol-17β are present to cytosol prepared from rabbit liver. When cytosol from sexually mature male liver was incubated with [3H]estradiol and analyzed for binding on low ionic strength sucrose gradients, two peaks of binding activity were detected. One peak had a sedimentation coefficient of 4–5 S and the other had a sedimentation coefficient of 8–9 S. The two components differed from each other regarding steroid specicity and various physiocochemical parameters. [3H]-estradiol binding to the 4–5 S component was not inhibited by estrogens, 5α-dihydrotestosterone, progesterone or cortisol. Binding to this component did not appera to be saturable and lavel was rapidly stripped from it by cahrcoal. Estradiol bindng to the 8–9 S component was estrogen specific, saturable and of high affinity. The specific binder dissociates on high ionic strength sucrose gradients and sediments as a 4–5 S moiety. The specific binding protein has a Kd of 3.05 · 10−10 M and a dissociation half-time of 33 h and there are 35.2 fmol of binding sites/mg cytosol protein. Estrogen binders are also present in liver cytosol from sexually mature female and sexually immature male rabbits. During prolonged incbuation of [3H]estradiol with mature male liver cytosol at 0–5°C polar metabolites of estradiol are produced. 相似文献
4.
Victor S. Sivozhelezov 《Molecular Engineering》1996,6(4):405-414
Ionic strength dependencies of electron transfer between Cytochrome b
5 and variants of yeast Cytochrome c were analyzed by curve fitting to the simple model of the electrostatic interaction between the two proteins assuming the process to be non-diffusion-controlled. Mutagenesis of Lys79, but not Lys72, leads to an increase of effective radius of the interacting charged species, suggesting that the mutation effects of the two residues on the electrostatic field distribution near the contact site are different, even within the crude electrostatic model used. Extrapolation of the ionic strength dependencies to infinite ionic strength resulted in similar values, around (2–3)×10-6 for all Cyt c variants considered thus showing the lysine residue mutations to primarily affect protein association rather than the electron transfer directly. Based on the ionic strength dependencies of binding constants of the two proteins into an electrostatically stabilized complex, the monomolecular electron transfer rate constant was estimated to be 1.1×104–1.6×105 s-1. The electrostatic part of the binding energy of the complex at I=0.19 was estimated to be-2.4 kcal/mol, strongly at variance with the values-13.0 and-6.4 kcal/mol reported for the two types of complexes identified using Brownian dynamics techniques. Possible reasons for this discrepancy are discussed. 相似文献
5.
The H-2.7 antigen in normal mouse serum can be passively adsorbed to H-2.7– erythrocytes in 10 percent sucrose (low ionic strength) solution. This antigen can also be stripped off the H-2.7+ erythrocytes under the same conditions provided the H-2.7+normal serum is absent. The stripped red blood cells can regain the H-2.7 antigen upon reincubation with H-2.7+ normal serum. The attachment of the H-2.7 antigen to erythrocytes probably occurs via a specific receptor.Abbreviations used in this paper BSA
bovine serum albumin
- B10
C57BL/10Sn
- HA
hemagglutination
- LIS
low ionic strength solution
- NMS
normal mouse serum
- PBS
phosphate-buffered saline
- PVP
polyvinylpyrrolidone
- RBCs
red blood cells 相似文献
6.
《Journal of receptor and signal transduction research》2013,33(2):261-275
AbstractThe binding of 3H-estriol was examined in the fetal uterus of guinea pig. The physico-chemical characteristics of the binding of 3H-estriol to macromolecules are similar to the typical receptor protein for estrogens. Different estrogens (estriol, estradiol, estrone and diethylstilbestrol) compete with this binding but progesterone and testosterone have no effect. The binding affinity has a Kd of 5.5 ± 1.6 ± 10?10M. By ultra-centrifugation in sucrose gradient, two specific components with sedimentation coefficients of 8 and 45 are found. Competition studies suggest that the same specific binding sites may be present for estriol (E3) and for estradiol. The s.c. administration of E3 to the pregnant guinea pig (1 mg/day per kg body weight for 3 days) provokes two biological responses in the fetal uterus: a uterotrophic effect and a significant increase in the progesterone receptor. The increase in the fetal uterine weight is 50–70% in relation to the non-treated animals and the progesterone receptor concentration is 10–14 times higher than in the control animals. These effects are similar (or slightly higher) than in animals primed with equimolecular quantities of estradiol. In contrast, single daily injections of E3 to newborn guinea pig, results only in weak uterotrophic activity.It is concluded that estriol is capable of causing a biological response in the uterus during intra-uterine life. 相似文献
7.
Abstract A simple method is described for preparative cell electrophoresis. Solid glass beads (? 0.1 mm diameter) are used as packing material in a cylindrical glass column, the interstices of which contain a citric acid-phosphate buffer of pH 7.6 and 0.015 ionic strength. Cell mixtures containing ? 6 × 109 erythrocytes in 0.2 ml are electrophoresed at 25 V/cm for 1–2 hours after which the column contents are extruded and the separated cell fractions recovered. Complete separation was achieved between mixtures of human and chicken erythrocytes and untreated and papain-treated human erythrocytes. The electrophoretic mobilities of cells subjected to this procedure are in good agreement with previously published mobilities, obtained by microelectrophoresis. 相似文献
8.
PeiHua Chen Xiao-dong Liu Wei Zhang Jun Zhou Ping Wang Wei Yang JianHong Luo 《中国科学:生命科学英文版》2009,52(11):1036-1047
Based on patch clamp data on the ionic currents of rat taste receptor cells, a mathematical model of mammalian taste receptor cells was constructed to simulate the action potentials of taste receptor cells and their corresponding ionic components, including voltage-gated Na+ currents and outward delayed rectifier K+ currents. Our simulations reproduced the action potentials of taste receptor cells in response to electrical stimuli or sour tastants. The kinetics of ion channels and their roles in action potentials of taste receptor cells were also analyzed. Our prototype model of single taste receptor cell and simulation results presented in this paper provide the basis for the further study of taste information processing in the gustatory system. 相似文献
9.
The main physicochemical properties of the polysaccharide called Xanthan produced by Xanthomonas compestris are discussed: the activity coefficient of the counter-ion, the pK(α), and the ionic selectivity are investigated and compared to those of a carboxymetholcellulose. The weight-average molecular weight (M w = 2 × 106), the intrinsic viscosity and the constant of sedimentation are determined as a function of the ionic strength. It is proved that in dilute solution, there is no intermolecular association, whatever the ionic strength. The conformation is proposed to be a rigid rodlike molecule whose length is 6000 Å, independent of ionic strength > 10?2N. 相似文献
10.
Robert M. Riehl David O. Toft Michael D. Meyer Gerald L. Carlson Trevor C. McMorris 《Experimental cell research》1984,153(2):544-549
Sexual reproduction among the eukaryotic fungi of the genus, Achlya, is controlled by two steroid pheromones. Antheridiol is the pheromone constitutively produced by female cells that induces male sexual differentiation and development. A biologically active tritium-labeled derivative of antheridiol, [1,2-3H]7-deoxy-7-dihydro-antheridiol ([3H]7dA), has been synthesized. Radioligand-binding studies have revealed the presence of a specific binding protein in the cytosol of male cells that may represent the endogenous receptor for antheridiol. Binding to this macromolecule was characterized by an apparent equilibrium dissociation constant and maximum binding capacity of approx. 7 × 10−10 M and 1 100–2 000 fmoles/mg protein, respectively. Sedimentation analysis in sucrose gradients revealed that the binding protein distributes in the 8S region under low ionic strength and sodium molybdate-stabilized conditions. Under conditions of high ionic strength, in the presence or absence of 10 mM sodium molybdate, the binding site distributes in the 3.6S region of the gradient. Analysis of radioligand binding in the presence of other steroids and steroid hormones revealed that the binding is specific for antheridiol and its analog. 相似文献
11.
Plasma estradiol and cytosolic estradiol receptor levels of testes were determined in a group of young (2–3 months) and old (24 months) Sprague-Dawley rats. Estradiol binding sites for the young rats averaged 5.6 ± 0.3 fmol/mg protein (), which was comparable to that of the old rats, 5.7 ± 0.3 fmol/mg protein (n=12). Using Scatchard analyses, the association constants at equilibrium of estradiol receptor binding of the old and young rats were the same, 6.1 × 1010M?1. Plasma estradiol levels were also similar in both groups-19.6 ± 2.8 pg/ ml (n=14) for the young and 19.2 ± 2.6 pg/ml (n=10) for the old rats. Our results suggest that impaired testosterone biosynthesis in old rats was not due to elevated plasma estradiol levels or to differences in testicular estradiol receptor content. 相似文献
12.
Yong-Beom Park Chul-Won Ha Jin-A Kim Ji-Heon Rhim Yong-Geun Park Jun Young Chung Han-Jun Lee 《PloS one》2016,11(11)
BackgroundMesenchymal stem cells (MSCs) are known to have therapeutic potential for cartilage repair. However, the optimal concentration of MSCs for cartilage repair remains unclear. Therefore, we aimed to explore the feasibility of cartilage repair by human umbilical cord blood-derived MSCs (hUCB-MSCs) and to determine the optimal concentrations of the MSCs in a rabbit model.MethodsOsteochondral defects were created in the trochlear groove of femur in 55 rabbits. Four experimental groups (11 rabbits/group) were treated by transplanting the composite of hUCB-MSCs and HA with various MSCs concentrations (0.1, 0.5, 1.0, and 1.5 x 107 cells/ml). One control group was left untreated. At 4, 8, and 16 weeks post-transplantation, the degree of cartilage repair was evaluated grossly and histologically.FindingsOverall, transplanting hUCB-MSCs and HA hydrogel resulted in cartilage repair tissue with better quality than the control without transplantation (P = 0.015 in 0.1, P = 0.004 in 0.5, P = 0.004 in 1.0, P = 0.132 in 1.5 x 107 cells/ml). Interestingly, high cell concentration of hUCB-MSCs (1.5×107 cells/ml) was inferior to low cell concentrations (0.1, 0.5, and 1.0 x 107 cells/ml) in cartilage repair (P = 0.394,P = 0.041, P = 0.699, respectively). The 0.5 x 107 cells/ml group showed the highest cartilage repair score at 4, 8 and 16 weeks post transplantation, and followed by 0.1x107 cells/ml group or 1.0 x 107 cell/ml group.ConclusionsThe results of this study suggest that transplantation of the composite of hUCB-MSCs and HA is beneficial for cartilage repair. In addition, this study shows that optimal MSC concentration needs to be determined for better cartilage repair. 相似文献
13.
摘要 目的:探究不孕症患者的子宫自然杀伤细胞、浆细胞与子宫内膜异位症的相关性。方法:选择80例患有子宫内膜异位症的不孕症患者做为本研究的不孕症组和80例正常生育的健康女性做为本研究的健康组,对比分析两组患者人口学基本资料、子宫自然杀伤细胞(uNKs)、浆细胞(PC)水平、血清性激素水平、子宫内膜中血管内皮生长因子(VEGF)表达情况、免疫细胞水平。通过Person法分析不孕症患者的子宫自然杀伤细胞、浆细胞与子宫内膜异位症的相关性。结果:两组的BMI指数、流产史、吸烟史、饮酒史比较,差异有统计学意义(P<0.05);不孕症组患者uNKs、抗苗勒氏管激素(AMH)和黄体生成素(LH)水平均显著高于健康组;PC、卵泡刺激素(FSH)、雌激素(Estrogen)和性激素结合球蛋白(SHBG)、VEGF阳性表达水平、CD4+、CD8+和CD4+/CD8+水平均显著低于健康组,差异有统计学意义(P<0.05)。另外,不孕症患者的uNKs与子宫内膜异位症存在显著的正相关关系(r=1.555,P<0.001);PC与子宫内膜异位症存在显著的负相关关系(r=-3.778,P<0.001)。结论:不孕症患者的uNKs、PC参与不孕症的发生和发展过程,对女性子宫内膜异位症的诊断具有重要的参考意义。 相似文献
14.
Hannes Vietzen Svenja Hartenberger Stephan W. Aberle Elisabeth Puchhammer-Stckl 《PLoS neglected tropical diseases》2021,15(12)
BackgroundInfections with the Puumala orthohantavirus (PUUV) in humans may cause hemorrhagic fever with renal syndrome (HFRS), known as nephropathia epidemica (NE), which is associated with acute renal failure in severe cases. In response to PUUV-infections, a subset of potent antiviral NKG2C+ NK cells expand, whose role in virus defence and pathogenesis of NE is unclear. NKG2C+ NK cell proliferation is mediated by binding of NKG2C/CD94 to HLA-E on infected cells. The proliferation and activation of NKG2C+ NK cells via the NKG2C/HLA-E axis is affected by different NKG2C (NKG2Cwt/del) and HLA-E (HLA-E*0101/0103) alleles, which naturally occur in the human host. Homozygous (NKG2Cdel/del) and heterozygous (NKG2Cwt/del) deletions of the NKG2C receptor results in an impaired NKG2C/CD94 mediated proliferation and activation of NKG2C+ cells. We therefore analyzed the PUUV-mediated NKG2C+ NK cell responses and the impact of different NKG2C and HLA-E alleles in NE patients.Methodology/Principal findingsNKG2C+ NK cell expansion and effector functions in PUUV-infected cells were investigated using flow cytometry and it was shown that PUUV-infected endothelial cells led to a NKG2C/CD94 mediated NKG2C+ NK cell activation and expansion, dependent on the HLA-G-mediated upregulation of HLA-E. Furthermore, the NKG2Cdel and HLA-E*0101/0103 alleles were determined in 130 NE patients and 130 matched controls, and it was shown that in NE patients the NKG2Cwt/del allele was significantly overrepresented, compared to the NKG2Cwt/wt variant (p = 0.01). In addition, in vitro analysis revealed that NKG2Cwt/del NK cells exhibited on overall a lower proliferation (p = 0.002) and lower IFNγ expression (p = 0.004) than NKG2Cwt/wt NK cells.Conclusions/SignificanceOur results corroborate the substantial impact of the NKG2C/HLA-E axis on PUUV-specific NK cell responses. A weak NKG2C+ NK cell response, as reflected by NKG2Cwt/del variant, may be associated with a higher risk for a severe hantavirus infections. 相似文献
15.
A. T. Karapetyan E. E. Minyat P. O. Vardevanyan V. I. Ivanov 《Journal of biomolecular structure & dynamics》2013,31(6):1233-1238
Abstract Poly[d(G-C)] in a 55% ethanol solution undergoes a transition from the Z form to the B form when the temperature is increased from 20° to 50°C. The enthalpy of the transition, ΔHBA =—1.4 kcal/mol, has been determined with a “tie” polyamine which stabilizes the Z conformation. This value has been shown to be practically independent of ionic strength within the range of 5 x 104 M—2 x 103 M NaCl. 相似文献
16.
Down-regulation of Bcl-2 enhances estrogen apoptotic action in long-term estradiol-depleted ER<Superscript>+</Superscript> breast cancer cells 总被引:4,自引:0,他引:4
Song RX Zhang Z Mor G Santen RJ 《Apoptosis : an international journal on programmed cell death》2005,10(3):667-678
Postmenopausal women with estrogen receptor positive (ER+) breast cancer frequently respond paradoxically to estrogen administration with tumor regression. Using both LTED and E8CASS cells derived from MCF-7 breast cancer cells by long-term estrogen-deprivation, we previously reported that 17 -estradiol (estradiol) is a powerful, pro-apoptotic hormone which kills the cancer cells through activation of the Fas/FasL death receptor pathway. We postulated that the mitochondrial interactive protein Bcl-2 might play a role in the regulation of estradiol-induced apoptosis in both LTED and E8CASS cells. In this study, we assessed estradiol effects on cell growth, proliferation and apoptosis. Additionally we investigated the effect of estradiol on caspase activation, NF-KB and Bcl-2 expression. The functional role of Bcl-2 in estradiol-induced apoptosis was further studied by knockdown or decrease of Bcl-2 with siRNA. Our results show that estradiol significantly inhibited cell growth primarily through a pro-apoptotic action involving caspase-7 and 9 activations (p < 0.01). Basal Bcl-2 and NF-KB levels were greatly elevated and estradiol decreased NF-KB, but not Bcl-2 expression. Knockdown of Bcl-2 expression with siRNA decreased the levels of this protein by 9 fold (p < 0.01). This reduction markedly sensitized both LTED and E8CASS cells to the pro-apoptotic action of estradiol, leading to a synergistic induction of apoptosis and a concomitant reduction in cell number (p < 0.01). Therefore, down-regulation of Bcl-2 synergistically enhanced estradiol-induced apoptosis in ER+ postmenopausal breast cancer cells. 相似文献
17.
Antonio Gianguzza Francesco Maggio Silvio Sammartano 《Chemical Speciation and Bioavailability》2013,25(1-2):17-21
ABSTRACTProtonation constants and Na+-, Mg2+-, Ca2+-, Zn2+- and Cd2+-D-Glucuronate complex formation constants have been determined potentiometrically in different ionic strength conditions. Glucuronate forms a very weak complex species with Na+ (K ~ 1 dm3 mol?1), and weak species with Mg2+ and Ca2+ (K ~ 10 dm3 mol?1). When glucuronate interacts with Zn2+ and Cd2+, two species, M(gluc) and M(gluc)2 (glue = glucuronate) having a stability intermediate between that of mono and dicarboxylate complexes, are formed. This can be due to the involvement of the ethereal oxygen in the coordination. Medium effects are considered in the light of speciation problems. 相似文献
18.
摘要 目的:提取小鼠骨髓细胞(bone marrow cell, BMC),用两种不同的免疫磁珠分离(magnetic activated cell sorting, MACS)试剂盒从小鼠BMC中分选提纯粒-单核祖细胞(granulocyte-monocyte progenitor, GMP),比较这两种免疫磁珠的分选效率。方法:从小鼠股骨和胫骨中提取BMC,通过两种不同的MACS试剂盒,即Lineage阳性细胞清除试剂盒和CD117阳性细胞分选试剂盒,分别得到Lineage-细胞群和CD117+细胞群,用代表GMP细胞表面标志物的荧光抗体标记,孵育后通过流式细胞荧光分选技术得到GMP细胞,并且对比得到GMP细胞的效率。结果:每2只野生型C57BL/6J小鼠可共收集骨髓细胞(7.02±1.24)×107个,细胞活力为(91.86±5.24)%。经过Lineage阳性细胞清除试剂盒得到的细胞数量为(5.71±2.86)×106个;经过CD117阳性细胞分选试剂盒得到的细胞数量为(2.70±0.56)×106个。Lineage磁珠分选纯化得到的GMP细胞数占总细胞数的比例为(10.90±1.37)%,CD117磁珠分选纯化得到的GMP细胞数占总细胞数的比例为(4.83±2.08)%。结论:Lineage阳性细胞清除试剂盒能更有效分选小鼠骨髓细胞中的粒-单核祖细胞。 相似文献
19.
《Journal of receptor and signal transduction research》2013,33(2-3):133-151
AbstractA stable recombinant Chinese hamster ovary (CHO) cell model system expressing the human type-1 receptor for parathyroid hormone and parathyroid hormone-related peptide (hPTH-R) was established for the analysis of human PTH (hPTH) variants. The cell lines showed receptor expression in the range from 105 to 1.9xl06 receptors per cell. The affinity of the receptors for hPTH-(l-34) was independent of the receptor number per cell (K<j = 8 nmol/1). The induction of cAMP by hPTH-(l-34) is maximal in clones expressing >2xl05 receptors per cell and Ca++ signals were maximal in cell lines expressing >1.4xl06 receptors per cell. Second messenger specific inhibitors demonstrated that PTH-induced increases in intracellular cAMP and Ca++ are independent and Ca++ ions are derived from intracellular stores. The cAMP-specific receptor activator hPTH-(l-31) showed also an increase in intracellular Ca++. Even in cell lines expressing more than 10 receptors per cell the Ca++/PKC specific activator hPTH-(28-48) did not activate hPTH-Rs. Based on these results, synthesis of further derivatives of PTH is required to identify pathway-specific ligands for the type-1 hPTH-R. 相似文献
20.
Estradiol binding components in the cytosol and nuclear fractions of the ovary from immature rats (22–28 days old) were characterized by methods. Several of the biochemical characteristics of the estradiol binding components in the ovarian tissue were compared with the estradiol receptor from the uterus. The results suggest that the ovarian estradiol binding components are similar to the specific high affinity estradiol receptors in the uterus. In the cytosol of intact rat ovary a significant fraction of the total binding sites was found to be occupied, presumably by the endogenous estrogen. Following hypophysectomy there was a significant increase in the available cytosol binding sites. Evidence for translocation of cytosol receptor-estrogen (RE) complex to the nucleus was obtained for the ovary. The sedimentation properties of the RE complex of the ovary and the uterus are similar. The ovarian cytosol RE complex sediments at 7-8S in glycerol gradients at low ionic strength and at 4S in sucrose gradients at high ionic strength. Following extraction with 0.4 M KCl the ovarain nuclear RE complex sediments at 5S in sucrose gradients which is identical to that of the uterine nuclear receptor. 相似文献