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1.
Renal concentrating mechanism: possible role for sodium-potassium activated adenosine triphosphatase 总被引:2,自引:0,他引:2
M Martinez-Maldonado J C Allen G Eknoyan W Suki A Schwartz 《Science (New York, N.Y.)》1969,165(895):807-808
Sodium-potassium activated adenosine triphosphatase activity was found to be almost twice as high in renal medulla as in cortex. Infusion of digoxin, a specific inhibitor of the enzyme, into one renal artery of the dog resulted in unilateral natriuresis, impaired concentrating capacity, and reduction of the enzyme activity in both cortex and medulla. It is suggested that the sodium-potassium adenosine triphosphatase plays an important role in urine concentration mechanisms. 相似文献
2.
Cyclosporin A, a potent immunosuppressive agent, has been widely used to treat patients with solid organ transplants. Although its precise mechanism of action is unknown, it appears to inhibit subsets of T lymphocytes at an early stage in cell activation. Fluorescent, fully active derivatives of cyclosporin A and calmodulin, a protein that binds calcium and is therefore essential to normal cell function, were utilized to demonstrate that cyclosporin A binds to calmodulin. Flow cytometry showed that the calmodulin inhibitors R24571 and W-7 competitively inhibited binding of cyclosporin A to cloned T lymphocytes. Cyclosporin A inhibited the calmodulin-dependent activation of phosphodiesterase in a dose-dependent manner. Binding of cyclosporin A to calmodulin may prevent the latter's role in the activation of the second messengers and enzymes required for effective cell proliferation and function in the immune response. 相似文献
3.
Flagellar adenosine triphosphatase from sea urchin sperm: properties and relation to motility 总被引:1,自引:0,他引:1
Adenosine triphosphatase activated by divalent cations is apparently a component of the motile apparatus in flagella of Arbacia sperm, as judged by the activity of this enzyme in intact flagella, glycerol-extracted flagella, and soluble extracts prepared from flagella. However, the variation in the physical properties and in the amount of enzyme obtained after a variety of treatments suggests that additional components are involved in the motile mechanism. These features distinguish the soluble flagellar enzyme from adenosine triphosphatases of other motile cells. 相似文献
4.
Sodium-potassium adenosine triphosphatase: acyl phosphate "intermediate" shown to be L-glutamyl-gamma-phosphate 总被引:3,自引:0,他引:3
Peptides obtained from pepsin digestion of the phosphorylated and nonphosphorylated forms of a preparation of brain microsomal sodium-potassium-activated adenosine triphosphatase were treated at pH 5.4 with N-(n-propyl-2,3-(3)H) hydroxylamine of high specific activity, then separated by column chromatography, and further digested with pronase. A compound isolated in higher amounts from the phosphorylated enzyme than from the nonphosphorylated enzyme migrated with authentic L-glutamyl-gamma-propylhydroxamate in four chromatographic systems and on electrophoresis on paper at three different pH's. The acyl phosphate "intermediate" in the phosphorylated form of the adenosine-triphosphatase therefore appears to be an L-glutamyl-gamma-phosphate residue. 相似文献
5.
Na~+、K~+和Cl~-对玉米营养和毒性的比较研究 总被引:2,自引:0,他引:2
用NaCl、KCl、NaNO3和KNO34种盐处理非盐生植物玉米 (Zeamays)幼苗 ,比较Na+ 、K+ 和Cl- 的营养性和毒性。低浓度时 ,Na+ 、K+ 和Cl- 对玉米的生长都有促进作用 ,其中K+ 的促进作用明显 ;高浓度处理时 ,Na+ 、K+ 和Cl- 的效应有差异。NaCl和KCl处理时 ,Cl- 表现出明显的毒性 ;NaNO3和KNO3处理时 ,Na+ 表现出的毒害作用较K+ 强。低浓度的Na+ 和Cl- 促进玉米叶片叶绿素的合成 ;高浓度的Cl- 导致脯氨酸含量明显升高 ,植株干枯或黄化。 相似文献
6.
Widespread occurrence in frogs and toads of skin compounds interacting with the ouabain site of Na+, K+-ATPase 总被引:3,自引:0,他引:3
Amphibians of the family Bufonidae contain high levels of skin compounds that both inhibit Na+- and K+-dependent adenosinetriphosphatase and antagonize the binding of ouabain to the enzyme. In species of Bufo and Atelopus, these compounds are relatively nonpolar bufodienolides, whereas Dendrophryniscus and Melanophryniscus contain more polar compounds of unknown structure. Skin extracts from 30 of 48 species of frogs representing an additional eight families contained relatively low levels of compounds that inhibit binding of ouabain to Na+,K+-adenosinetriphosphatase. The widespread occurrence of low levels of inhibitory compounds is consonant with the role for these compounds as physiological regulators of Na+,K+-adenosinetriphosphatase in amphibian skin; high levels in the Bufonidae probably also serve as a defense against some predators. 相似文献
7.
Sodium- and potassium-activated adenosine triphosphatase of gills: role in adaptation of teleosts to salt water 总被引:8,自引:0,他引:8
The activity of adenosine triphosphatase activated by sodium and potassium ions is greatly increased in the gill and pseudobranch of the euryhaline killifish, Fundulus heteroclitus, after its adaptation to seawater. Adenosine triphosphatase activity in gills of fish in salt water is reduced by hypophysectomy. The data suggest that this enzyme is involved in the excretion of sodiumions by the gill and that the adaptive increase which occurs in seawater is influenced by the hypophysis. 相似文献
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采用人工饲养实验方法,将黄鳝暴露于亚致死浓度的Cu2+污染环境(0.7—4.5mg·L-1)120h后,每隔24h对黄鳝肝脏、性腺组织及其线粒体中(Na++K+)-ATPase活性进行了检测。结果显示,黄鳝(Na++K+)-ATPase活性随着Cu2+污染浓度升高而降低。0.7mg·L-1的Cu2+污染对黄鳝(Na++K+)-ATPase活性影响小;Cu2+浓度大于3.0mg·L-1时,黄鳝(Na++K+)-ATPase活性受到较强的抑制。受Cu2+的污染,黄鳝(Na++K+)-ATPase活性随处理时间的变化在不同的组织表现出相类似的规律,即抑制-恢复-抑制过程。 相似文献
10.
CHEN Hua-tao CHEN Xin WU Bing-yue YUAN Xing-xing ZHANG Hong-mei CUI Xiao-yan LIU Xiao-qing 《中国农业科学(英文版)》2015,(6)
Sodium toxicity and potassium insufifcient are important factors affecting the growth and development of soybean in saline soil. As the capacity of plants to maintain a high cytosolic, K+/Na+ratio is t... 相似文献
11.
研究了大丽轮枝菌(Verticillium dahliae)在不同钾钠比(K~+/Na~+)的查氏培养基中生长的生物学特性及致病力的变化。结果表明,菌株在0K~+/Na~+≤5.248的固体培养基上生长呈近M型,在K~+/Na~+5.248的固体培养基上生长呈近W型。与常规查氏培养基(CK,K~+/Na~+为1.312)相比,菌株在0K~+/Na~+5.248区间的固体培养基上,生长速率明显上升;在K~+/Na~+5.248的固体培养基上,生长速率无显著性差异;在K~+/Na~+为5.248的固体培养基上,菌核型菌株的微菌核产量最大;但在无K~+条件下同样有微菌核的产生,说明K~+对微菌核的产生有一定影响,在适中情况下会增加菌株微菌核的产量,但非必要产生因素。K~+浓度会影响到菌株的致病力,当K~+/Na~+≤2.624时,随着K~+浓度的上升,菌株的致病力有所增强,当K~+浓度过高,K~+/Na~+达到26.24时,菌株的致病力反而减弱。在K~+浓度不变时,Na~+浓度与病原菌的致病力初步呈正相关,Na~+浓度升高,钾钠比下降,病原菌的致病力增强;反之亦然。 相似文献
12.
To reveal the insecticidal mechanism of terpinen-4-ol, the activity of Na+,K+-ATPase in insects tested were determined in vivo and in vitro. The results showed that terpinen-4-ol and its ester derivatives had strong contact activity to housefly and the contact toxicities of its derivatives except Z3 were all superior or equivalent to terpinen-4-ol. All the 7 compounds had strong inhibition towards activity of Na+,K+-ATPase. With poisoning symptom exacerbating, the inhibition rates were gradually increased. In vitro, the IC50 of terpinen-4-ol, Z1, Z2, Z4, Z5, and Z6 was 155.89, 197.98, 96.02, 121.36, 124.85, and 153.74 μg mL% respectively. There was well correlation between the LDs0 of terpinen-4-ol derivatives to housefly and the IC50 of terpinen-4-ol derivatives to Na+,K+-ATPase in housefly. In conclusion, Na+,K+-ATPase was likely the target of terpinen-4-ol against insects. 相似文献
13.
【目的】探讨松油烯-4-醇的杀虫作用机理。【方法】采用点滴法测定了松油烯-4-醇及其6种酯类衍生物乙酸酯(Z1)、丙酸酯(Z2)、丙烯酸酯(Z3)、苯甲酸酯(Z4)、苯磺酸酯(Z5)、对甲苯磺酸酯(Z6)对家蝇成虫的触杀活性及对其体内Na+,K+-ATPase活性的影响。【结果】松油烯-4-醇及其酯类衍生物对家蝇均具有一定的触杀活性,除丙烯酸酯外,其它酯类衍生物的触杀毒力均高于或相当于松油烯-4-醇;活体条件下,7种化合物均对Na+,K+-ATPase具有较强的抑制作用,且随着中毒症状的加剧,对该酶的抑制作用增强;离体条件下,松油烯-4-醇及其乙酸酯、丙酸酯、苯甲酸酯、苯磺酸酯、对甲苯磺酸酯衍生物对家蝇Na+,K+-ATPase的IC50分别为155.89、197.98、96.02、121.36、124.85、153.74μg8226;ml-1;分析发现松油烯-4-醇及其酯类衍生物对家蝇24 h的触杀LD50与对Na+,K+-ATPase的IC50之间具有显著相关性。【结论】Na+,K+-ATPase可能是松油烯-4-醇类化合物的主要作用靶标。 相似文献
14.
【目的】进一步探明盐胁迫条件下营养元素K+、Ca2+和Mg2+对苗期不同水稻基因型耐盐性的影响差异,为明确作物耐盐胁迫的生理机制、提高作物耐盐胁迫能力提供参考。【方法】于2009年1—4月在严格控制水、温、光和营养元素供应的国际水稻研究所人工气候室进行水培试验,比较研究营养液中K+、Ca2+和Mg2+浓度的变化对不同水稻基因型苗期耐盐性的影响。【结果】在盐胁迫条件下(100mmol·L-1NaCl),耐盐基因型(FL478和IR651)与盐敏感基因型(IR29和Azucena)相比,植株体内有较低的Na+含量和Na+/K+、Na+/Ca2+、Na+/Mg2+比,有较高的K+含量,这些都是耐盐基因型耐盐胁迫能力高于盐敏感基因型的内在原因。盐胁迫条件下提高营养液中Ca2+和Mg2+的含量(60mg·L-1),可显著降低植株体Na+含量和Na+/K+、Na+/Ca2+、Na+/Mg2+比,明显减轻盐胁迫的危害,增强水稻耐盐胁迫能力,且Ca2+处理的效果优于Mg2+处理;而提高营养液K+含量对以上指标的影响远远小于Ca2+处理和Mg2+处理,这也是K+处理对水稻耐盐性影响相对不明显的内在原因。【结论】K+、Ca2+和Mg2+在植株体内的含量及其与Na+的比值变化都会影响水稻苗期耐盐性;适当提高水稻生长环境的Ca2+和Mg2+浓度可以明显增强植株耐盐胁迫能力,营养元素Ca2+的效果比Mg2+明显;而K+对水稻耐盐性的影响相对不明显。 相似文献
15.
Ca(2+)-induced Ca2+ release in sea urchin egg homogenates: modulation by cyclic ADP-ribose 总被引:19,自引:0,他引:19
Calcium-induced calcium release (CICR) may function widely in calcium-mediated cell signaling, but has been most thoroughly characterized in muscle cells. In a homogenate of sea urchin eggs, which display transients in the intracellular free calcium concentration ([Ca2+]i) during fertilization and anaphase, addition of Ca2+ triggered CICR. Ca2+ release was also induced by the CICR modulators ryanodine and caffeine. Responses to both Ca2+ and CICR modulators (but not Ca2+ release mediated by inositol 1,4,5-trisphosphate) were inhibited by procaine and ruthenium red, inhibitors of CICR. Intact eggs also displayed transients of [Ca2+]i when microinjected with ryanodine. Cyclic ADP-ribose, a metabolite with potent Ca(2+)-releasing properties, appears to act by way of the CICR mechanism and may thus be an endogenous modulator of CICR. A CICR mechanism is present in these nonmuscle cells as is assumed in various models of intracellular Ca2+ wave propagation. 相似文献
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17.
为了解斑尾复鰕虎鱼的渗透压调节机制,设置0.5、10、15、20、25、30、35、40、50共10个盐度组,采用外界盐度渐变的方法对该鱼幼鱼血清渗透压、血清离子浓度及鳃丝Na+/K+–ATP酶活力进行了检测和分析。结果显示:在盐度0~50内,血清渗透压及血清离子含量均随盐度升高而升高,盐度为40~50时,血清渗透压及各离子含量均显著高于对照组(盐度6);在0~35的盐度中,血清渗透压及离子含量都保持相对稳定,在0盐度组,鳃丝Na+/K+–ATP酶活性最强,25和35盐度组的鳃丝Na+/K+–ATP酶活性比5~20和40~50盐度组的明显增强,25和35盐度组之间Na+/K+–ATP酶活性无显著性差异,5~20和40~50盐度组之间也均无显著差异,在盐度5~35内,鳃丝Na+/K+–ATP酶活性随外界盐度升高呈升高趋势;回归分析得到血清等渗点为0.308 mol/kg,相对应的盐度为10.8;Na+、Cl–、K+等离子点分别为340.28、137.08和4.51 mmol/L,相对应的盐度分别为28.1、8.9和18.5。以上结果表明,斑尾复鰕虎鱼幼鱼对外界盐度变化有较强的适应性,属于广盐性鱼类,其盐度的耐受范围和适宜范围分别为0.3~35和5~15。 相似文献
18.
Suping Wang Yongxia Jia Shirong Guo Guoxian Zhou 《Frontiers of Agriculture in China》2007,1(4):430-437
Seedlings from the salt-sensitive cucumber cultivar Jinchun No. 2 and the salt-tolerant cucumber cultivar Changchun Mici were
exposed for 8 days to 50 mmol/L NaCl in the absence or in the presence of exogenous foliar spraying PAs [putrescine (Put),
spermidine (Spd), and spermine (Spm) 1 mmol/L] to compare the effects of different kinds of polyamines (PAs) on plant tolerance
to salinity. This paper studied the effects of exogenous PAs on K+, Na+ and Cl− in different organs of cucumber seedlings. The results showed that K+ content as well as the ratios of K/Na and Cl/Na decreased, while Na+ and Cl− concentrations increased in salt-treated cucumber seedlings. The differences in K+, Na+ and Cl− content and the K/Na and Cl/Na ratios were greater for the salt sensitive cultivar Jinchun No. 2 than for the salt-tolerant
cultivar Changchun Mici. Cucumber seedlings treated with exogenous polyamines and combined with salinity exhibited a higher
level of K+ accumulation and lower levels of Na+ and Cl− accumulation compared with the seedlings treated only with salt stress. Among the three kinds of polyamines, Spd and Spm
were more effective in inhibiting the accumulation of Na+ and reduction of K+. However, Put was more effective in reducing Cl− accumulation. Furthermore, all of the three kinds of exogenous polyamines could increase the ratio of K/Na, improving the
absorption and transport selectivities of K+ and Na+ from stems to leaves for both cultivars. In conclusion, exogenous polyamines could alleviate salt damage to some extent and
enhance the accumulation of biomass. Among the three kinds of polyamines, spermidine was most effective. Exogenous polyamines
could improve tolerance of cucumber seedlings under salt stress by regulating the absorption and distribution of ions in different
organs.
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Translated from Acta Ecologica Sinica, 2007, 27(3): 1122–1129 [译自: 生态学报] 相似文献
19.
喹乙醇对鲤鳃组织Na+、K+-ATP酶活性及血浆生化指标的影响 总被引:5,自引:0,他引:5
用含不同喹乙醇剂量的饲料饲喂健康鲤鱼种,研究饲料中不同喹乙醇剂量对鲤体成分含量、血浆生化指标以及鲤鳃组织.Na^ 、K^ -ATP酶活性的影响,探讨喹乙醇对鲤的生化毒性。试验分成6个喹乙醇处理组(0、200、400、800、1600、3200mg/kg),试验期60d。试验结束时分别从各组中采血、取全鱼样和鱼鳃样,进行不同指标测试。结果表明,喹乙醇使鱼体脂肪含量轻度上升,使灰分沉积量显著降低,并呈现剂量一反应关系。与对照组比较,在较高喹乙醇剂量下,谷草转氨酶(AST)、肌酸激酶(CK)活性降幅较大,血浆中葡萄糖(GLU)、胆固醇(CHO)、总胆红素(T-B)、直接胆红素(D-B)、高密度脂蛋白(HDL)、白蛋白(ALB)、K^ 、Ca^2 、P含量升高,肌酐(CRE)和CO2含量降低,其他测定指标变化不明显。鳃组织中Na^ 、K^ -ATP酶活性随喹乙醇剂量的升高而呈逐渐下降的趋势,呈现剂量效应关系,喹乙醇剂量达1600mg/k以上时,Na^ 、K^ -ATP酶活性显著降低。结论:1600mg/k以上的喹乙醇剂量可以明显干扰鲤的正常生化代谢功能。 相似文献
20.
Dextran sulfate suppression of viruses in the HIV family: inhibition of virion binding to CD4+ cells 总被引:42,自引:0,他引:42
H Mitsuya D J Looney S Kuno R Ueno F Wong-Staal S Broder 《Science (New York, N.Y.)》1988,240(4852):646-649
The first step in the infection of human T lymphocytes by human immunodeficiency virus type 1 (HIV-1) is attachment to the target cell receptor, the CD4 antigen. This step may be vulnerable to attack by antibodies, chemicals, or small peptides. Dextran sulfate (molecular weight approximately 8000), which has been given to patients as an anticoagulant or antilipemic agent for more than two decades, was found to block the binding of virions to various target T lymphocytes, inhibit syncytia formation, and exert a potent inhibitory effect against HIV-1 in vitro at concentrations that may be clinically attainable in human beings. This drug also suppressed the replication of HIV-2 in vitro. These observations could have theoretical and clinical implications in the strategy to develop drugs against HIV types 1 and 2. 相似文献