Sodium and potassium activities in normal and "sodium-rich" frog skeletal muscle

In frog sartorius muscles immersed for 2 hours at 26 degrees C in normal Ringer solution, the intrafiber potassium concentration, C(K)(in millimoles per liter), was 123 +/- 2 (mean value plus or minus standard error), and the potassium activity, a(K) (in millimoles per liter), was 90 +/- 1.0. The corresponding sodium concentration and activity were 20 +/- 1 and 6.5 +/- 0.4, respectively. After overnight immersion in K+-free Ringer solution the values were: CK, 97 +/- 2; aK, 81.5 +/- 1.6; CNa, 47 +/- 2; and aNa, 11.2 +/- 0.6. The changes in aK and aNa during storage were not consistent with an exchange between predominantly "free" fiber K+ and external Na+. These results suggest that the Na+ taken up during overnight immersion largely replaced adsorbed or sequestered K+ in the fibers.     

高密度和高盐度对缢蛏渗透调节和抗氧化水平的影响

以缢蛏(Sinonovacula constricta)为实验对象,研究密度(60和120粒/m²)和盐度(20和30)对缢蛏渗透调节和抗氧化水平的影响,实验持续72 h,检测了缢蛏血淋巴Na⁺浓度和K⁺浓度,肝胰腺组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量,以及鳃组织中Na⁺/K⁺-ATPase活性、钠氢逆向转运蛋白(Na⁺/H⁺ antiporter)和膜泡质子泵(V-ATPase)基因表达水平。结果显示：密度和盐度对缢蛏血淋巴Na⁺浓度、K⁺浓度无显著交互影响作用,高盐组Na⁺浓度、K⁺浓度显著高于对照组;在实验12 h和24 h时,密度和盐度对Na⁺/K⁺-ATPase活性的影响具有显著交互作用,并且高盐度组和高密度组Na⁺/K⁺-ATPa...     

Alteration of alpha 1 Na+,K(+)-ATPase 86Rb+ influx by a single amino acid substitution

The sodium- and potassium-dependent adenosine triphosphatase (Na+,K(+)-ATPase) maintains the transmembrane Na+ gradient to which is coupled all active cellular transport systems. The R and S alleles of the gene encoding the Na+,K(+)-ATPase alpha 1 subunit isoform were identified in Dahl salt-resistant (DR) and Dahl salt-sensitive (DS) rats, respectively. Characterization of the S allele-specific Na+,K(+)-ATPase alpha 1 complementary DNA identified a leucine substitution of glutamine at position 276. This mutation alters the hydropathy profile of a region in proximity to T3(Na), the trypsin-sensitive site that is only detected in the presence of Na+. This mutation causes a decrease in the rubidium-86 influx of S allele-specific sodium pumps, thus marking a domain in the Na+,K(+)-ATPase alpha subunit important for K+ transport, and supporting the hypothesis of a putative role of these pumps in hypertension.     

海水灌溉对椰子幼苗叶片若干生理特性的影响

以海南本地高种与文椰2号矮种2个有代表性的椰子品种幼苗为试材,在温室大棚条件下,采用盆栽土培法,研究不同浓度海水对2种椰子幼苗叶片相对含水量、丙二醛、可溶性糖、脯氨酸、K+、Na+含量及K+/Na+值等生理特性的影响。结果表明:低浓度海水灌溉(30%),2种椰子幼苗长势良好,叶片相对含水量、可溶性糖、脯氨酸、K+、Na+含量及K+/Na+值等生理特性与对照相比无明显差异。随着海水浓度的升高,2种椰子幼苗各项指标与对照组的差异逐渐明显。高浓度海水灌溉(90%)时,海南本地高种与文椰2号叶片相对含水量及K+/Na+值均显著降低,脯氨酸、可溶性糖、Na+含量显著升高;海南本地高种较文椰2号Na+含量变化幅度大,K+/Na+值下降更剧烈,而文椰2号矮种叶片相对含水量下降趋势更为明显、可溶性糖含量变化幅度更大,脯氨酸变化趋势相近。2种椰子幼苗中丙二醛含量变化均较为复杂,呈现先升高后降低再升高的趋势。     

Ouabain resistance conferred by expression of the cDNA for a murine Na+, K+-ATPase alpha subunit

The molecular basis for the marked difference between primate and rodent cells in sensitivity to the cardiac glycoside ouabain has been established by genetic techniques. A complementary DNA encoding the entire alpha 1 subunit of the mouse Na+- and K+-dependent adenosine triphosphatase (ATPase) was inserted into the expression vector pSV2. This engineered DNA molecule confers resistance against 10(-4) M ouabain to monkey CV-1 cells. Deletion of sequences encoding the carboxyl terminus of the alpha 1 subunit abolish the activity of the complementary DNA. The ability to assay the biological activity of this ATPase in a transfection protocol permits the application of molecular genetic techniques to the analysis of structure-function relationships for the enzyme that establishes the internal Na+/K+ environment of most animal cells. The full-length alpha 1 subunit complementary DNA will also be useful as a dominant selectable marker for somatic cell genetic studies utilizing ouabain-sensitive cells.     

Responses of Contrasting Rice （Oryza sativa L.） Genotypes to Salt Stress as Affected by Nutrient Concentrations

The study was conducted to investigate the effects of applying different concentrations of the macronutrients K+,Ca2+,and Mg2+on the responses of contrasting rice(Oryza sativa L.)genotypes under salt stress.A solution culture experiment was conducted in a phytotron at the International Rice Research Institute(IRRI),under controlled temperature and humidity and natural sunlight.When subjected to salt stress of 100 mmol L-1 using NaCl,the salt tolerant genotypes FLA78 and IR651,accumulated less Na+and maintained lower ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+than the sensitive genotypes IR29 and Azucena.These tolerant genotypes also had higher concentrations of K+in their shoots and greater root and shoot biomass and green leaf area.Tolerant genotypes also maintained much lower concentration of Na+and lower and more favorable ratios of Na+/K+,Na+/Ca2+,and Na+/Mg2+in their active and developing tissues.Salt tolerance and shoot and root growth of both tolerant and sensitive genotypes were enhanced considerably when higher concentrations of Ca2+and Mg2+were applied in culture solution.The concentration of Na+and the ratios of Na+/K+,Na+/Ca2+.and Na+/Mg2+ in shoots also declined significantly.The beneficial effects of higher calcium were greater than that of magnesium and application of higher concentration of K+seems to have minor effects.Responses to salinity in rice can therefore be considerably enhanced through proper nutrient management,by increasing the concentrations of nu～ient elements that have favorable effects such as Ca2+and Mg2+Calcium is particularly more effective than both magnesium and potassium,and can be applied at relatively larger quantities in salt affected soils.     

Potassium ion: is the bulk of intracellular K+ adsorbed?

When a major portion of the intracellular K(+) in frog muscle is reversibly replaced by Na(+), the extra Na(+) gained by the cells does not show the nuclear magnetic resonance signal that free Na(+) does. The data contradict the membrane theory but are in accord with the concept that the bulk of intracellular K(+) is adsorbed.     

Active transport of potassium and chloride in an identifiable molluscan neuron

Direct measurements of intracellular K(+) and Cl(-)activities before and after blockage of cellular metabolic processes indicate that K(+) is actively transported inwardly and Cl(-)is actively transported outwardly from the giant cell of the abdominal ganglion of Aplysia. The rewarming of cells that have been cooled to 1 degrees +/- 1 degrees C causes K(+) to be taken up and Cl(-) to be extruded against electrochemical gradients.     

Voyager radio science observations of neptune and triton

The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.01. Preliminary representative results include the following: 1.0243 x 10(26) and 2.141 x 10(22) kilograms for the masses of Neptune and Triton; 1640 and 2054 kilograms per cubic meter for their respective densities; 1355 +/- 7 kilometers, provisionally, for the radius of Triton; and J(2) = 3411 +/- 10(x 10(-6)) and J(4) = -26(+12)(-20)(x10(-6)) for Neptune's gravity field (J>(2) and J(4) are harmonic coefficients of the gravity field). The equatorial and polar radii of Neptune are 24,764 +/- 20 and 24,340 +/- 30 kllometers, respectively, at the 10(5)-pascal (1 bar) pressure level. Neptune's atmosphere was probed to a pressure level of about 5 x 10(5) pascals, and effects of a methane cloud region and probable ammonia absorption below the cloud are evident in the data. Results for the mixing ratios of helium and ammonia are still being investigated; the methane abundance below the clouds is at least 1 percent by volume. Derived temperature-pressure profiles to 1.2 x 10(5) pascals and 78 kelvins (K) show a lapse rate corresponding to "frozen" equilibrium of the para- and ortho-hydrogen states. Neptune's ionosphere exhibits an extended topside at a temperature of 950 +/- 160 K if H(+) is the dominant ion, and narrow ionization layers of the type previously seen at the other three giant planets. Triton has a dense ionosphere with a peak electron concentration of 46 x 10(9) per cubic meter at an altitude of 340 kilometers measured during occultation egress. Its topside plasma temperature is about 80 +/- 16 K if N(2)(+) is the principal ion. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; however, the accuracy of the measurements is limited by uncertainties in the frequency of the spacecraft reference oscillator. Preliminary values for the surface pressure of 1.6 +/- 0.3 pascals and an equivalent isothermal temperature of 48 +/- 5 K are suggested, on the assumption that molecular nitrogen dominates the atmosphere. The radio data may be showing the effects of a thermal inversion near the surface; this and other evidence imply that the Triton atmosphere is controlled by vapor-pressure equilibrium with surface ices, at a temperature of 38 K and a methane mixing ratio of about 10(-4).     

K~+,Ca~(2+)和Mg~(2+)对不同水稻(Oryza sativa L.)基因型苗期耐盐性的影响

【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。     

NaCl胁迫对不同甘薯品种体内离子分配的影响

以济薯21、济徐23、济薯04150、徐薯26、徐薯27和徐薯28共6个甘薯品种为试材,用1/5 Hoag-land营养液附加不同浓度NaCl(0、0.2%、0.3%和0.5%)处理甘薯苗,观察其生长情况;100 d后取样分别测定根、茎、叶中的Na+含量和K+含量。结果表明,随着NaCl浓度升高,不同甘薯品种的生长均受到抑制,其中徐薯26受抑制程度最大;根、茎、叶中的Na+含量及Na+/K+比值都有所增加,根中Na+含量最高,而叶中Na+含量最低。可见盐胁迫条件下甘薯将较多的Na+储存在根中从而减少对地上部叶片的伤害,这可能是其忍耐高盐环境的重要机制之一。     

苦菜耐盐机理初探

在水培条件下,研究了不同浓度海盐溶液对苦菜体内游离脯氨酸、Na+含量以及地上部Na+/K+的影响。结果表明:游离脯氨酸是苦菜在盐胁迫下起主要作用的有机渗透调节物质;苦菜根中Na+含量高于叶中Na+含量;随盐浓度增加,苦菜地上部Na+/K+变大,因此,初步认为苦菜是一种拒盐植物。     

不同钾钠比的查氏培养基对大丽轮枝菌生物学性状及致病力的影响

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。     

NaCl胁迫对甘薯试管苗生长及离子含量影响

[目的]探讨甘薯的耐盐机理。[方法]用浓度分别为0、100 mmol/LNaCl处理耐盐性不同的2个甘薯品种徐25-2(耐盐品种)和胜利百号(盐敏感品种),培养20 d后以火焰光度计测定根、茎、叶中的Na+含量、Na+/K+比值,并测不同品种的根、茎、叶的干重、鲜重。[结果]盐胁迫下,2个甘薯品种的生长均受抑制,导致植株矮小、叶片变少、根系稀少、根叶干物质减少,但是徐25-2幼苗受抑制程度较轻;此外,2个甘薯品种不同器官(根、茎、叶)的Na+含量及Na+/K+比值都增加,耐盐性强的徐25-2的Na+含量在根、茎和叶片中较低,而耐盐性较弱的胜利百号幼苗茎、叶Na+含量较高,但徐25-2的变化幅度均小于胜利百号。[结论]盐胁迫下叶片较低的Na+含量和Na+/K+比值是甘薯品种耐盐性的重要特征。     

表鱼藤酮对映体杀虫作用机理的研究

 【目的】阐明表鱼藤酮对映体（-）-5′α-表鱼藤酮与（+）-5′β-表鱼藤酮的杀虫作用与机理。【方法】以3龄家蚕幼虫为试虫，比较药剂处理24、72 h后中毒症状，及对线粒体呼吸酶复合体Ⅰ、Na+，K+-ATP酶、琥珀酸脱氢酶、乙酰胆碱酯酶活性差异。【结果】表鱼藤酮对映体处理后的3龄家蚕幼虫中毒症状明显不同；对线粒体呼吸酶复合体Ⅰ都有抑制活性，5′α-表鱼藤酮、5′β-表鱼藤酮抑制中浓度IC50分别为7.81、54.14 mg•L-1；对家蚕头部Na+，K+-ATP酶都有抑制作用；5′β-表鱼藤酮对中肠Na+，K+-ATP酶表现为抑制作用，5′α-表鱼藤酮表现为激活作用；对琥珀酸脱氢酶5′α-表鱼藤酮有激活作用；对乙酰胆碱酯酶活性没有影响。【结论】表鱼藤酮对映体的毒力及对线粒体呼吸酶复合体Ⅰ抑制活性有差异；对映体间引起的中毒症状差异与线粒体呼吸酶复合体Ⅰ的结合方式和中肠Na+，K+-ATP酶，琥珀酸脱氢酶有关。     

NaCl胁迫对甘薯试管苗生长和离子含量的影响

[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato. [Method] Two sweet potato varieties of Xu 25-2 (salt-tolerant cuhivar) and Triumph 100 (salt-sensitive cultivar) were treated by sodium chloride with the concentration of 0 mmol/L and 100 mmol/L. After 20 days, Na+ content and Na+/K+ ratio in the roots, shoots and leave were determined by the flame photometer, while dry weight and fresh weight of roots, shoots and leave in different varieties were also studied. [Result] The growth of two sweet potato varieties was inhibited under salt stress, so the plant became shorter, leaf and root became fewer, dry weight of roots and leave decreased, but seedlings of Xu 25-2 were inhibited slightly. Furthermore, Na+ content and Na+/K+ ratio in roots, shoots and leaves of two sweet potato varieties increased. Na+ content of salt-tolerant Xu 25-2 was low in roots, shoots and leaves, while Na+ content of salt-sensitive Triumph 100 was high in shoots and leave of seedlings, but the change range of Xu 25-2 was less than that of Triumph 100. [Conclusion] The lower Na+ content and Na+/K+ ratio in leaves under salt stress were the most important characteristics for salt-tolerance of sweet potato varieties.     

盐胁迫下树木的K+和Na+含量变化特点及其耐盐性

通过几种主要造林树种在盐胁迫下体内Na+和K+含量变化的分析,对树木耐盐性及其机理进行了讨论.结果表明:不同树种的Na+和K+含量及在盐胁迫下的变化动态存在明显差异,说明其耐盐机制不同,树木的Na+和K+的质量比值,随NaCl的质量浓度的增加而上升、其上升幅度在耐盐性强的白榆中较小;在盐胁迫下,适当地增加Ca2+,可维持树木体内较低的Na+和K+的质量比,从而提高树木耐盐性.     

D-glucose: preferential binding to brush borders disrupted with tris(hydroxymethyl)aminomethane

The actively transported sugar D-glucose binds to brush borders disrupted with tris(hydroxymethyl)aminomethane in preference to D-mannose and L-glucose, which are not actively transported. This preferential binding of D-glucose is not dependent on either added Na(+) or adenosine triphosphatase activity stimulated by Na(+) with K(+) and Mg(2+), but it is temperature-dependent and is completely inhibited by 0.1 millimolar phlorizin and 1 millimolar mercuric chloride.     

耐盐锻炼黑果枸杞适应盐胁迫的特征

  目的  明确耐盐锻炼黑果枸杞适应长期盐渍化胁迫的机理,为其修复极端干旱区盐渍化土壤提供依据。  方法  应用回归分析及主成分分析低盐胁迫（MSS）、中盐胁迫（HSS）和高盐胁迫（SS）土壤黑果枸杞各器官K+、Na+和Ca2+区隔化特征,器官干质量和根系形态对盐胁迫的响应。  结果  （1）NaCl浓度小于183.63 mmol/L,耐盐锻炼黑果枸杞植株成活率随着NaCl浓度增加而增大,NaCl浓度 ≥ 355.88 mmol/L植株全部死亡。随着NaCl浓度升高,花期到初果期果实相对生长速率显著减缓,初果期到果实完全成熟期果实相对生长速率加快。（2）HSS处理的根K+和Na+显著高于MSS和SS,茎中K+、Na+和Ca2+含量均显著低于MSS和SS。HSS处理的根和茎中K+/Na+和Ca2+/Na+差异不显著。SS处理的叶Ca2+分别是MSS和HSS的5和3倍。SS处理的根和茎Na+含量没有显著差异,根和叶Ca2+含量也没有显著差异。胁迫程度从MSS上升到SS,茎中Na+含量平均增加0.78 g/kg。（3）PCA分析表明,主成份1（PCA1）和主成份2（PCA2） 共解释了黑果枸杞适应盐胁迫的73.9%。PCA1可解释黑果枸杞盐胁迫的57.8%信息,其中,地上器官干质量对PCA1贡献最大,按照对PCA1贡献率大小排序为叶干质量、茎干质量、根干质量和主根直径。PCA1与根Na+含量、地上器官Na+含量和侧根直径呈显著负相关。株高、根Ca2+含量、茎粗、地上器官K+/Na+、根干质量、主根直径与PCA1呈正相关。植株K+/Na+、根系K+/Na+、根际土壤K+/Na+、根Ca2+含量和地上器官Ca2+含量可以解释PCA2盐胁迫的16.1%信息,上述指标均与PCA2呈显著负相关。  结论  随着盐胁迫程度增加,叶维持高浓度Ca2+调控植株体K+/Na+,根和茎富集储存Na+能力显著增强,说明经过耐盐锻炼黑果枸杞倾向于不同器官协同分担盐胁迫以适应长期盐胁迫。      

盐胁迫对黄蜀葵生长及金丝桃苷含量的影响

通过种子萌发试验和盆栽试验,探讨了盐胁迫对黄蜀葵种子发芽、生长发育、植株体内离子分布以及金丝桃苷含量的影响。结果表明,盐胁迫对黄蜀葵种子萌发有一定的抑制作用,随着盐浓度的增加,其发芽率呈下降趋势;低浓度NaCl胁迫有利于黄蜀葵生长,其中,0.3%的NaCl处理下生长发育较好;盐处理后,黄蜀葵根中Na+和K+含量显著高于茎与叶,Ca2+含量、K+/Na+和Ca2+/Na+值显著低于茎与叶;随NaCl浓度提高,根中Na+含量逐渐增加,各个器官中Ca2+和K+含量均呈上升趋势。盐胁迫对黄蜀葵花冠中金丝桃苷含量影响显著,当NaCl浓度为0.3%时,金丝桃苷含量达到最高,但当NaCl浓度为0.7%时,金丝桃苷含量急剧下降。认为黄蜀葵为耐盐植物,适度的盐胁迫可以提高黄蜀葵花冠中金丝桃苷的含量。