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1.
Two forms of autosomal chronic granulomatous disease lack distinct neutrophil cytosol factors 总被引：28，自引：0，他引：28
Chronic granulomatous diseases of childhood (CGD) are a group of disorders of phagocytic cell superoxide (O2.-) production (respiratory burst). Anion exchange chromatography separated from normal neutrophil cytosol a 47-kilodalton neutrophil cytosol factor, NCF-1, that restored activity to defective neutrophil cytosol from most patients with autosomally inherited CGD in a cell-free O2.--generating system. A 65-kilodalton factor, NCF-2, restored activity to defective neutrophil cytosol from one patient with autosomal CGD. NCF-1, NCF-2, and a third cytosol fraction, NCF-3, were inactive alone or in pairs, but together replaced unfractionated cytosol in cell-free O2.- generation. Neutrophils deficient in NCF-1, but not NCF-2, did not phosphorylate the 47-kilodalton protein. It is proposed that NCF-1, NCF-2, and NCF-3 are essential for generation of O2.- by phagocytic cells and that genetic abnormalities of these cytosol components can result in the CGD phenotype. 相似文献
2.
Two cytosolic neutrophil oxidase components absent in autosomal chronic granulomatous disease 总被引：31，自引：0，他引：31
Neutrophils kill microorganisms with oxygen radicals generated by an oxidase that uses the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as substrate. This system requires both membrane and cytosolic components and is defective in patients with chronic granulomatous disease. A cytosolic complex capable of activating latent membrane oxidase was eluted from guanosine triphosphate-agarose and was used to raise polyclonal antiserum that recognized 47- and 67-kilodalton proteins. These proteins were restricted to the cytosol of myeloid cells. Both proteins were associated with NADPH oxidase-activating capacity when neutrophil cytosol was purified on nucleotide affinity matrices or molecular sizing columns. Neutrophils from patients with two different forms of autosomal chronic granulomatous disease lacked either the 47- or 67-kilodalton protein. 相似文献
3.
Establishment and maintenance of an intracellular niche are critical to the success of an intracellular pathogen. Here, the pore-forming protein listeriolysin O (LLO), secreted by Listeria monocytogenes, was shown to contain a PEST-like sequence (P, Pro; E, Glu; S, Ser; T, Thr) that is essential for the virulence and intracellular compartmentalization of this pathogen. Mutants lacking the PEST-like sequence entered the host cytosol but subsequently permeabilized and killed the host cell. LLO lacking the PEST-like sequence accumulated in the host-cell cytosol, suggesting that this sequence targets LLO for degradation. Transfer of the sequence to perfringolysin O transformed this toxic cytolysin into a nontoxic derivative that facilitated intracellular growth. 相似文献
4.
A cytosolic protein catalyzes the release of GDP from p21ras 总被引：35，自引：0，他引：35
The rate of release of guanine nucleotides from the ras proteins (Ras) is extremely slow in the presence of Mg2+. It seemed likely, therefore that a factor might exist to accelerate the release of guanosine diphosphate (GDP), and hence the exchange of GDP for guanosine triphosphate (GTP). Such a factor has now been discovered in rat brain cytosol. Brain cytosol was found to catalyze, by orders of magnitude, the release of guanine nucleotides from recombinant v-H-Ras protein bound with [alpha-32P]GDP. This effect occurred even in the presence of a large excess of Mg2+, but was destroyed by heat or by incubation of the cytosol for an hour at 37 degrees C in the absence of phosphatase inhibitors. The effect was observed with either v-H-Ras or c-H-Ras, but not with p25rab3A, a small G protein with about 30% similarity to Ras. The effect could not be mimicked by addition of recombinant Ras-GAP or purified GEF, a guanine nucleotide exchange factor involved in the regulation of eukaryotic protein synthesis. By gel filtration chromatography, the factor appears to possess a molecular size between 100,000 and 160,000 daltons. This protein (Ras-guanine nucleotide-releasing factor, or Ras-GRF) may be involved in the activation of p21ras. 相似文献
5.
采用一种类Fenton试剂法,即Fe3+和H2O2的组合代替Fe2+和H2O2的组合法,对氧化降解苯酚的影响因素及反应动力学进行研究。结果表明:当Fe3+、H2O2的加入量分别为1.3×10-3和1.3×10-2mol·L-1,且初始pH值约为4时,苯酚的降解率最大,几乎达到100%。同时分别用一级动力学、二级动力学及复合一级动力学方程对该条件下的反应进行拟合,复合一级动力学方程能最佳拟合相应的动力学过程,但2个平行反应的速率系数k1≈9.24k2,因此可近似认为是一级动力学过程。 相似文献
6.
连续流A／O／A工艺中反硝化聚磷菌的富集及种群跟踪 总被引：1，自引：0，他引：1
[目的]为反硝化除磷工艺的实际应用提供依据。[方法]利用连续流A／O／A工艺富集反硝化聚磷菌,并采用平板计数法和PCR—DGGE法对功能茵群进行跟踪和鉴定。[结果]活性污泥中的反硝化菌、聚磷茵和反硝化聚磷菌分别增加了7．1×10^2、8．1×10^4和8．0×10^5倍;稳定运行时活性污泥中存在3种优势茵种,a菌群与产碱杆菌属的同源性高达96％,为反硝化聚磷茵;b菌群与副球菌属的同源性高达94％,同样为反硝化聚磷茵;c菌群与紫色杆菌属的同源性高达96％,既是一种反硝化茵,也是一种酵解茵。其中副球菌具有反硝化聚磷功能尚未见报道;稳定运行出水指标为：COD47．0mg／L、PO4^3-P0．2mg／L、NH4一N2．6mg／L和NO3-一N3．5mg／L。[结论]采用先启动膜法硝化池、后启动泥法反硝化除磷池（厌氧和缺氧）的功能茵富集方式是可行的,且A／O／A工艺是可达到《城镇污水处理厂污染物排放标准》（GB18918-2002）一级A标准的要求。 相似文献
7.
Cyclophilin: a specific cytosolic binding protein for cyclosporin A 总被引：89，自引：0，他引：89
R E Handschumacher M W Harding J Rice R J Drugge D W Speicher 《Science (New York, N.Y.)》1984,226(4674):544-547
Cyclophilin, a specific cytosolic binding protein responsible for the concentration of the immunosuppressant cyclosporin A by lymphoid cells, was purified to homogeneity from bovine thymocytes. Cation-exchange high-performance liquid chromatography resolved a major and minor cyclophilin species that bind cyclosporin A with a dissociation constant of about 2 X 10(-7) moles per liter and specific activities of 77 and 67 micrograms per milligram of protein, respectively. Both cyclophilin species have an apparent molecular weight of 15,000, an isoelectric point of 9.6, and nearly identical amino acid compositions. A portion of the NH2-terminal amino acid sequence of the major species was determined. The cyclosporin A-binding activity of cyclophilin is sulfhydryl dependent, unstable at 56 degrees C and at pH 4 or 9.5, and sensitive to trypsin but not to chymotrypsin digestion. Cyclophilin specifically binds a series of cyclosporin analogs in proportion to their activity in a mixed lymphocyte reaction. Isolation of cyclophilin from the cytosol of thymocytes suggests that the immunosuppressive activity of cyclosporin A is mediated by an intracellular mechanism, not by a membrane-associated mechanism. 相似文献
8.
高淀粉甘薯0409-17高产栽培模式研究 总被引：1，自引：0，他引：1
采用三元二次正交旋转组合设计的方法,研究了种植密度和磷、钾肥施用量对高淀粉甘薯品系0409-17产量和淀粉的影响.结果表明,在种植密度为47 325~53 820株/hm2、施过磷酸钙(含P2O512%)115.5~367.5 kg/hm2、施氯化钾(含K2O 60%)27~226.5 kg/hm2的栽培模式下,能充分发挥该品系高产和高淀粉的潜力,甘薯鲜薯产量超过22 536.15 kg/hm2、淀粉产量超过5 679.3 kg/hm2. 相似文献
9.
[目的]初步预测牦牛源多杀性巴氏杆菌C47-8株(PmC47-8)OmpH蛋白结构特点。[方法]对PmC47-8型菌株OmpH基因的测序结果进行在线BLAST比对、信号肽预测、二级结构预测及蛋白特性等方面的分析。[结果]PmC47-8株OmpH基因与已公布的81条OmpH基因相似性在84%～99%间;OmpH蛋白序列中存在信号肽,切割位点在第20号和21号氨基酸残基之间;OmpH蛋白二级结构预测中,折叠结构占49.8%,环状结构占50.2%;推测OmpH蛋白有7个O型糖基化位点,分别是位于第2、45、48、330、716、721、723号位的氨基酸残基,2个N型糖基化位点,即第15和35号位的氨基酸残基。[结论]该蛋白可能存在于细胞菌膜的外侧,而非跨膜蛋白。 相似文献
10.
运用密度泛函理论方法,在B3LYP/6-311++G**水平上对4-氨基-1,2,4-三唑阳离子(AT)和2,4,6-三硝基苯酚阴离子(PA)形成的氢键二聚体进行理论计算研究.计算得到4种稳定结构的氢键复合物及最稳定异构体D1的振动频率、电子吸收光谱与热力学性质.结果表明,氢键复合物中存在较强的N—H…O与C—H…O红移氢键.经过基组重叠误差和零点振动能校正后,D1的氢键相互作用能为-30.71kJ/mol.热力学计算显示,在298.15K和标准状态下,D1气态氢键复合物分子的形成过程是放热、熵减小的非自发过程,但在低温下能自发进行.D1分子的标准摩尔生成焓和标准摩尔生成自由能分别为98.7,474.4kJ/mol. 相似文献
11.
Interleukin-8 (IL-8) is an inflammatory cytokine that activates neutrophil chemotaxis, degranulation, and the respiratory burst. Neutrophils express receptors for IL-8 that are coupled to guanine nucleotide-binding proteins (G proteins); binding of IL-8 to its receptor induces the mobilization of intracellular calcium stores. A cDNA clone from HL-60 neutrophils, designated p2, has now been isolated that encodes a human IL-8 receptor. When p2 is expressed in oocytes from Xenopus laevis, the oocytes bind 125I-labeled IL-8 specifically and respond to IL-8 by mobilizing calcium stores with an EC50 of 20 nM. This IL-8 receptor has 77% amino acid identity with a second human neutrophil receptor isotype that binds IL-8 with higher affinity. It also exhibits 69% amino acid identity with a protein reported to be an N-formyl peptide receptor from rabbit neutrophils, but less than 30% identity with all other known G protein-coupled receptors, including the human N-formyl peptide receptor. 相似文献
12.
[目的]对牦牛源多杀性巴氏杆菌C47-8株(PmC47-8)OmpH蛋白结构进行初步预测。[方法]对PmC47-8型菌株OmpH基因的测序结果进行在线BLAST比对、信号肽预测、二级结构预测及蛋白特性等方面的分析。[结果]PmC47-8株OmpH基因与已公布的81条OmpH基因相似性在84%～99%间;OmpH蛋白序列中存在信号肽,切割位点在第20号和21号氨基酸残基之间;OmpH蛋白二级结构预测中,折叠结构占49.8%,环状结构占50.2%;推测OmpH蛋白有7个O型糖基化位点,分别是位于第2、45、48、330、716、721、723号位的氨基酸残基,2个N型糖基化位点,即第15和35号位的氨基酸残基。[结论]该研究为牦牛源OmpH基因的免疫研究奠定基础。 相似文献
13.
尼罗罗非鱼DMRT蛋白B细胞表位的预测(英文) 总被引：1，自引：1，他引：0
[Objective] The research aimed to predict the B cell epitope of DMRT protein in Oreochromis niloticus. [Method] The secondary structure of amino acid sequence of DMRT protein was revealed by Garnier-Robson, Chou-Fasman and Karplus-Schulz methods. The hydrophilicity plot, surface probability and antigenic index were obtained by Kyte-Doolittle, Emini and Jameson-Wolf methods, respectively. Based on the above results, the B cell epitopes for DMRT were predicted. [Result] Both the prediction results from Garnier-Robson, Chou-Fasman methods indicated that the α-helix centers of DMRT protein in O. niloticus were in the N terminal No. 31-56, 68-75, 110-116, 209-211 and 239-243; the β-sheet centers of DMRT protein in O. niloticus were in the N terminal No. 95-99, 177-183, 225-234 and 251-254. With the assistant of Kyte-Doolittle, Emini and Jameson-Wolf methods, the B cell epitopes for DMRT were located in or nearby the N terminal No. 13-16, 35-38, 47-54,84-93, 101-109, 127-156, 166-177 and 198-201. [Conclusion] These results are helpful for preparing the antibody of DMRT protein and revealing the sex determination mechanism of O. niloticus. 相似文献
14.
The mutual control of the electric and magnetic properties of a solid is currently of great interest because of the possible application for novel electronic devices. We report on the low-magnetic-field (for example, B values of +/-30 milliteslas) control of the polarization (P) vector in a hexaferrite, Ba2Mg2Fe12O22, which shows the helimagnetic spin structure with the propagation vector k0 parallel to [001]. The B-induced transverse conical spin structure carries the P vector directing perpendicular to both B and k0, in accord with the recently proposed spin-current model. Then, the oscillating or multidirectionally rotating B produces the cyclic displacement current via the flexible handling of the magnetic cone axis. 相似文献
15.
16.
肥料效应函数在酒用高梁施肥技术中的应用 总被引：1，自引：0，他引：1
以贵州省金沙县的高粱施肥试验数据为基础,配置3类肥料效应函数,研究各类肥料效应函数的应用效果。结果表明：三元二次模型拟合N、P2O5、K2O肥平均推荐用量较一元二次、二元二次肥料效应模型分别低0．51～1．53kg／667m2、0．01～1．21kg／667m2、0．86～4．42kg／667m2;肥料效应函数推荐的金沙县高梁施肥配比为：N10．47kg／667m2、P2O5 3．79kg／667m2、K2O 10．58kg／667m2。在该县高粱施肥试验数据计算过程中,一元二次肥料效应模型和二元二次肥料效应模型拟合是对三元二次肥料模型拟合的补充和优化。 相似文献
17.
Wang HG Pathan N Ethell IM Krajewski S Yamaguchi Y Shibasaki F McKeon F Bobo T Franke TF Reed JC 《Science (New York, N.Y.)》1999,284(5412):339-343
The Ca2+-activated protein phosphatase calcineurin induces apoptosis, but the mechanism is unknown. Calcineurin was found to dephosphorylate BAD, a pro-apoptotic member of the Bcl-2 family, thus enhancing BAD heterodimerization with Bcl-xL and promoting apoptosis. The Ca2+-induced dephosphorylation of BAD correlated with its dissociation from 14-3-3 in the cytosol and translocation to mitochondria where Bcl-xL resides. In hippocampal neurons, L-glutamate, an inducer of Ca2+ influx and calcineurin activation, triggered mitochondrial targeting of BAD and apoptosis, which were both suppressible by coexpression of a dominant-inhibitory mutant of calcineurin or pharmacological inhibitors of this phosphatase. Thus, a Ca2+-inducible mechanism for apoptosis induction operates by regulating BAD phosphorylation and localization in cells. 相似文献
18.
Torardi CC Subramanian MA Calabrese JC Gopalakrishnan J Morrissey KJ Askew TR Flippen RB Chowdhry U Sleight AW 《Science (New York, N.Y.)》1988,240(4852):631-634
There is now a new series of high-temperature superconductors that may be represented as (A(III)O)(2)A(2)(II)Can-1CunO2+2n where A(III) is Bi or Tl, A(II) is Ba or Sr, and n is the number of Cu-O sheets stacked consecutively. There is a general trend toward higher transition temperatures as n increases. The highest n value for a bulk phase is three and is found when A(III) is Tl. This compound, Tl(2)Ba(2)Ca(2)Cu(3)O(10), has the highest transition temperature( approximately 125 K) of any presently known bulk superconductor. The structure of Tl(2)Ba(2)Ca(2)Cu(3)O(10) has been determined from single-crystal x-ray diffraction data and is tetragonal, with a = 3.85 A and c = 35.9 A. No superstructure is observed, and the material is essentially twin-free. Electron microscopy in the Tl/Ba/Ca/Cu/O system has revealed intergrowths where n = 5; such regions may well be responsible for the superconducting onset behavior observed in this system at about 140 K. 相似文献
19.
基于联合收获机的花生适机栽培技术研究 总被引：1，自引：0，他引：1
基于花生机械化收获地面损失率高的问题,采用L_9(3~4)正交试验设计,研究行距(A)、种植方式(B)、肥料用量(C)和追肥方式(D)等因素对产量的效应;同时采用联合收获机对不同种植方式的花生进行机械收获,测定地面损失率以验证最佳的种植方式。直观分析结果表明,各因素对花生籽仁产量效应主次排序为ACBD,以处理6(A_2B_3C_1D_2)的小区平均籽仁产量最高,但根据K均值大小选出的最优组合为A_2B_3C_1D_3,即:花生品种福花8号在沙性土壤中栽培,在基本苗27万株·hm~(-2)种植密度条件下,以畦宽90cm(含沟30cm),畦面宽55cm、行距33cm,组合交错(7~19cm)种植,全生育期施用纯N 52.5kg·hm~(-2)(N∶P_2O_5∶K_2O=1∶1.2∶0.8,其中P肥全部用作基肥,N、K肥基肥与追肥比例为1∶1),花生出苗后13d采取畦边撒施(覆土)的方式追施苗肥,盛花期叶面撒施450kg·hm~(-2)石灰的种植方式为佳。机械收获地面损失测定结果,组合交错种植方式的地面损失率是传统等位等距种植方式的1/6,是等距交错种植方式的2/5。 相似文献
20.
微肥与杀菌剂配施对玉米茎基腐病的防治及增产效果 总被引：1，自引：0，他引：1
研究了ZnSO_4·7H_2O、MnSO_4与五氯硝基苯可湿性粉剂和福美双可湿性粉剂配施防治玉米茎基腐病的效果及对玉米生长发育的影响。结果表明,微肥与杀菌剂配施,有利于促进玉米根系发育,培育壮苗,增强抗病能力,提高对玉米茎基腐病的防效。玉米拌种用量ZnSO_4·7H_2O6g/kg MnSO_46g/kg 50％福美双3g/kg 40％五氯硝基苯3g/kg,对玉米茎基腐病的防效88.75％～92.17％,较微肥处理和杀菌剂处理分别增产4.77％～6.42％和6.25％～11.80％。 相似文献