Cesium accumulation by bacterium Thermus sp. TibetanG7:hints for biomineralization of cesium-bearing geyserite in hot springs in Tibet,China

The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, China, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K , Na and K -regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K and Na , the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41 μmol Cesium/g cell dry weight in Na and K inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K -deficient cells showed a much higher capacity of cesium accu- mulation compared with K -sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.     

Structure of aqueous sodium sulfate solutions derived from X-ray diffraction

A rapid liquid X-ray diffractometer was used to study the time-averaged and space-averaged structure of aqueous sodium sulfate solutions at 298 and 323 K. Difference radial distribution functions of the solutions were obtained from accurate diffraction data. The interaction distances of Na^＋-OH2 and S-H2O in solutions were found to be 0.235 and 0.385 nm, respectively, after deconvolution of superposition peaks by Gaussian multi-peak fitting program. The characteristic distance of the NaSO; contact ion pairs in higher concentration solutions was determined to be 0.345 nm, suggesting that the Na^＋ ions coordinated with SO4^2- ions in the mono-dentate form. Effects of concentration and temperature on the hydration structure of the solutions were discussed in the present paper. With a decrease in concentration, the contributions of the H2O to the diffraction pattern increase, the average coordination number of the Na^＋ ions hardly changes, while the hydration number of SO4^2- ions increases slightly. The formation of NaSO; contact ion pairs becomes easier at higher temperature. The structure of hydrogen bond in dilute solutions is broken to a considerable extent with rising temperature, and the peak at 0.290 nm splits into two peaks at 0.275 and 0.305 nm, respectively.     

Prediction of Solid-Liquid Equilibrium for KCI in Mixed Water-Ethanol Solutions Using the LIQUAC Model

The LIQUAC model is often used to predict vapor-liquid equilibria, osmotic coefficients, and mean ion activity coefficients for electrolyte systems. This paper describes a thermodynamic method to analyze solid-liquid equilibrium for electrolytes in mixed solvents solutions using the LIQUAC model. The KCI solubilities in mixed water-ethanol solutions are predicted with the LIQUAC model and its original interaction parameters. This method is also used to obtain new K^＋-ethanol interaction parameters in the LIQUAC model from the solubility data. The new interaction parameters accurately predict the vapor-liquid equilibrium data of K^＋ salts （including KCI, KBr, and KCOOCH3） in mixed water-ethanol solutions. The results illustrate the flexibility of the LIQUAC model which can predict not only vapor-liquid equilibrium but also solid-liquid equilibrium in mixed solvent systems.     

Effects of inoculating fungi on agilawood formation in Aquilaria sinensis

Agilawood is a costly heartwood medicine obtained from Aquilaria sinensis with active ingredients mainly composed of volatile and semi-volatile substances. However, the formation time of agilawood is quite long and little is known about its formation mechanism. Two highly active fungi obtained from natural agilawood were inoculated on A. sinensis trees to understand their interaction processes and elucidate the transformation rules of induced chemical compositions within different test periods. The results demonstrated that the fungi could successfully colonize living tissues and cells and activate the host defense system, resulting in agilawood accumulation. With increasing time, the main components of A. sinensis converted into constituents or analogs of agilawood and the host exhibited "self-injury" to prevent fungal intrusion and protect other tissues. The data presented here could provide scientific basis for producing agilawood with the two new fungi in a safe, feasible, and sustainable manner without destroying rare Aquilaria plants.     

Crocin Synthesis Mechanism in Crocus sativus

Saffron （Crocus sativus） cells can synthesize crocin, crocetin digentiobiosyl ester, in suspension cultures. The crocin family biosynthesis mechanism was studied using high pressure liquid chromatography （HPLC） to determinate the glucosyltransferase activity and to develop a method for synthesizing medicine from saffron cells. Previous studies indicated that two glucosyltransferases might be involved in the formation of crocetin glucosyl- and gentiobiosyl-esters. GTasel formed an ester bond between crocetin carboxyl groups and glucose moieties while GTase2 catalyzed the formation of glucosidic bonds with glucosyl ester groups at both ends of the molecule. These enzymes can catalyze the formation of crocetin glucosides in vitro. GTasel activity is higher during the first four days of crocin glucosides biosynthesis, but decreases after four days. The formation and accumulation of crocin increase during the first six days and stabilized on the eighth day.     

Accumulation process and model for the Ordovician buried hill reservoir in the western Lunnan area,the Tarim Basin

The Ordovician buried hill reservoir in the western Lunnan area, a type of dissolved fracture and cavernous reservoir, is mainly composed of heavy oil. The oil is the mixture sourcing from the Middle-Lower Cambrian and Middle-Lower Ordovician, with three stages of pool forming process: (1) the destruction and parallel migration/accumulation during the late Caledonian to early Hercynian; (2) the oil and gas accumulation during the late Hercynian characterized by adjustment upward along faults and parallel migration/accumulation; (3) the formation of heavy oil during the latest Hercynian. The Ordovician buried hill reservoir is affected by the diffusion of light oil and gas but had no hydrocarbon charging during the late Yanshan period to Himalayan period, but in this period, formed the association of heavy oil and dissolved gas cracked from crude oil with dry coefficient of 0.91-0.96. The study on accumulation process of the Ordovician buried hill reservoir has important implications for the exploration potential of early oil and gas accumulation in the cratonic area of the Tarim Basin.     

Accumulation process and model for the Ordovician buried hill reservoir in the western Lunnan area, the Tarim Basin

The Ordovician buried hill reservoir in the western Lunnan area, a type of dissolved fracture and cavernous reservoir, is mainly composed of heavy oil. The oil is the mixture sourcing from the Middle-Lower Cambrian and Middle-Lower Ordovician, with three stages of pool forming process： （1） the destruction and parallel migration/accumulation during the late Caledonian to early Hercynian; （2） the oil and gas accumulation during the late Hercynian characterized by adjustment upward along faults and parallel migration/accumulation; （3） the formation of heavy oil during the latest Hercynian. The Ordovician buried hill reservoir is affected by the diffusion of light oil and gas but had no hydrocarbon charging during the late Yanshan period to Himalayan period, but in this period, formed the association of heavy oil and dissolved gas cracked from crude oil with dry coefficient of 0.91-0.96. The study on accumulation process of the Ordovician buried hill reservoir has important implications for the exploration potential of early oil and gas accumulation in the cratonic area of the Tarim Basin.     

Insight into the covalent grafting of organic films onto carbon steel surfaces for protection

The novel use of p-nitrophenyldiazonium tetrafluoroborate salt(GG salt)as a protectant that is electrochemically grafted onto carbon steel has been investigated in0.05 mol L-1H2SO4and 5 wt%NaCl solutions using various corrosion monitoring techniques,such as electrochemical impedance spectroscopy,potentiodynamic polarisation,infrared spectra and scanning electron microscopy measurements.The electrochemical study reveals that this compound is a mixed inhibitor that predominantly controls the cathodic reaction.The surface-grafted film decreases the double-layer capacitance and obviously increases the charge transfer resistance relative to a bare carbon electrode.The values of inhibition effect remain nearly unchanged with an increase in temperature range of 298–318 K.The aryl diazonium is covalently bonded on the steel surface,causing a slight decrease in the apparent activation energy.Overall,the surface-grafted films exhibit excellent inhibition performance in acid and saline solutions within the studied temperature range.     

Wave mechanics in quantum phase space: hydrogen atom

The rigorous solutions of the stationary Schrodinger equation for hydrogen atom are solved with the wave-mechanics method within the framework of the quantum phase-space representation established by Torres-Vega and Frederick. The "Fourier-like" projection transformations of wave function from the phase space to position and momentum spaces are extended to three-dimensional systems. The eigenfunctions in general position and momentum spaces could be obtained through the transformations from eigenfunction in the phase space.     

Impact of gamma radiation and salinity on growth and K^＋/Na^＋ balance in two populations of Medicago sativa （L.） cultivar Gabbs

The perennial Medicago sativa cv. Gabes is widely grown on saline soils in Tunisian oases. Morphological and physiological analyses of two populations （Mareth and Gannouch） were conducted in order to study the effect of salinity and gamma radiation （350 Gy） interaction on two populations of this species. It has been shown that the two irradiated populations of Medicago sativa are fairly tolerant to salt at growth phase compared to the non-irradiated. Exposure to gamma irradiation （350 Gy）, alone or in combination with salt stress, increased significantly （p 〈 0.001） shoot number, stem height and chlorophyll b pigment especially for the Gannouch population, while no change occurred for the Mareth population. The presence of salt to 9 g/1 affected significantly the root biomass and induced a reduction of shoot development of both control and irradiated alfalfa populations. For all treatments, plants of two populations remained able to produce and to allocate dry matter to the different organs. The survey of Na^＋/K^＋ ratio showed that the growth of the aerial organs of two non-irradiated populations was at least determined by a selectivity in favour of the K^＋ ions （r^2 = 0.97 and r^2 = 0.59 for Mareth and Gannouch non-irradiated populations, respectively）. However, the rather weak correlation detected for the irradiated populations, particularly for the irradiated Gannouch, seems to be the consequence of the effect of irradiation that improved potassium availability, essential element for growth and development. Results also showed that the two irradiated populations, especially the Mareth, accumulated Na^＋ ions in its photosynthetic organs. This accumulation was associated with an improvement of foliar water content at a level of salinity around 5 g/1. Such a mechanism reflects probably an inclusive behaviour of the plants and a good aptitude to use the dominant ions （Na^＋） for the osmotic adjustment. However, the non-irradiated populations are unable to adjust their internal os     

滇西二高温温泉中Thermus高温菌的16S rRNA

 通过对滇西二温泉纯培养和免培养法获得的Thermus菌株序列进行16SrDNA系统发育及16SrRNA二级结构比较,发现二温泉中至少存在Thermus属的2个潜在新种,它们在系统发育树上形成1个独立的地理簇群分支,它们的16SrRNAhelix10二级结构也与其它地区的Thermus属菌株不同,形成明显的地域进化特征.     

Studies on the overexpression of the soybean GmNHX1 in Lotus corniculatus： The reduced Na^＋ level is the basis of the increased salt tolerance

Soil salinity is one of the major factors reducing plant growth and productivity. The detrimental effects of salt on plants are a consequence of both a water deficit resulting in osmotic stress and the excess so- dium ions on critical biochemical processe…     

Effect of Cl- on photosynthetic bicarbonate uptake in two cyanobacteria Microcystis aeruginosa and Synechocystis PCC6803

Photosynthetic inorganic carbon utilization was investigated in two cyanobacteria Microcystis aeruginosa and Synechocystis PCC6803 grown in standing culture. Photosynthetic rates for the two algae reached about 10 times the theoretical CO₂ supply rate at low dissolved inorganic carbon (DIC) of 100 μmol/L, and the rates were unaffected by the addition of 20 mmol/L Na⁺, indicating that the two algae possessed Na+-independent HCO^-₃ utilization for photosynthesis under low DIC. Their photo- synthetic rates at low DIC were inhibited by higher Cl^- and the degrees of inhibition were increased with the rise of CI^- concentration, and in the presence of Diphenylamine-2-carboxylate (DPC), a reported Cl^- channel inhibitor, the rates decreased by 74%－82%, implying that putative DPC-sensitive Cl^- channels participate in Na+-independent HCO₃^- uptake for photosynthesis. The experiment of intracellular 14C-DIC accumulation for photosynthesis showed that internal DIC pools decreased by about 80% with 200 μmol/L DPC and by 64%－70% with 100 mmol/L Cl^-. The experiment of chlorophyll a fluorescence quenching showed that initial rates and extents of fluorescence quenching obviously decreased with 200 μmol/L DPC or 100 mmol/L Cl^-. The two experiments gave further evidence that putative DPC-sen- sitive Cl^- channels participate in Na+-independent HCO^-₃ uptake for photosynthesis in the two algae grown in standing culture.     

Reduced Na+ and K+ permeability of K+ channel in plasma membrane isolated from roots of salt-tolerant mutant of wheat

The Na⁺ and K⁺ permeability of K⁺ channel in plasma membrane, isolated from roots of the salt-tolerant mutant of wheat, was lower than that of wild type in 100 mmol/L KCl and NaCl solution. The opening frequency of K⁺ channel of the mutant reduced more significantly than that of wild type in two kinds of solution mentioned above. It is assumed that the reduction of opening frequency mainly contributes to the Na⁺ and K⁺ permeability of K⁺ channel of the mutant. The electric conductance of single-channel of the mutant was similar to that of wild type and the main difference between them was exhibited as the opening frequency. Their K⁺/Ka⁺ selectivity of K⁺ channel had no significant difference. The K⁺/Na⁺ selectivity of the mutant and wild type was 3.35 and 3.18 respectively.     

1株嗜碱放线菌的生理学特性研究及其鉴定

 对从青海茶卡盐湖岸土样中分离到的1株生理较特殊的嗜碱放线菌YIM80305的生长pH范围,不同碱性物质KOH,K₂CO₃,NaOH,Na₂CO₃对其生长的影响,耐NaCl,KCl特性进行了研究.同时从形态,细胞壁类型,16SrDNA等方面进行了鉴定.结果发现YIM80305对Na⁺碱性物质有一定依赖性,对K⁺敏感,YIM80305可能是Streptomyces属的1个新种.     

Regulation of the inward K+-channels in stomatal guard cells by cytoskeletal microtubules

Patch clamp techniques were applied to investigating the regulation of the inward K⁺-channels inVicia stomatal guard cells by cytoskeletal microtubules. The intracellular addition of either microtubule-disassembling reagent amprophos-methyl (APM) or microtubule-stabilizing reagent taxol resulted in significant inhibition of the inward K⁺-currents across the plasma membranes ofVicia stomatal guard cells. The results suggest that the activation of the inward K⁺-channels in stomatal guard cells requires proper dynamic organization of cytoskeletal microtubules. The regulation of the inward K⁺-channels in guard cells by microtubules may mediate the regulation of stomatal movements by cytoskeleton.     

Molecular characterization of a K+ channel blocker in the scorpionButhus martensii Karsch

K⁺ channel blockers of scorpion venoms are of important value in studying pharmacology and physiology of specific K⁺ channel of cells. Based on the amino acid sequences of BmP01 previously characterized as a small-conductance Ca²⁺-activated K⁺ channel blocker, two “back to back” degenarate primers have been designed and synthesized for inverse PCR strategy, its full-length cDNA has been cloned from the venom gland of the Chinese scorpionButhus martensii. The cDNA is composed of 3 parts: 5′ UTR, ORF and 3′ UTR. The flanking sequence of translation initiation codon ATG is AAAATGA, which is highly conserved in scorpion Na⁺ channel toxin and protozoan genes, suggesting that these genes may have followed a common mechanism for translation initiation. The 3′ UTR contains poly(A) signal AATAAA. The open reading frame encodes a precursor of 57 residues with a signal peptide of 28 residues and a mature peptide of 29 residues. The signal peptide is rich in hydrophobic amino acid residues and its length is significantly different from that of the determined scorpion Na⁺ channel toxin. The deduced amino acid sequence of mature peptide is completely consistent with BmP01 previously determined by primary structure analysis.     

超声波下酸化碘酸钾和亚硫酸钠反应的反应速率研究

分别测定在有超声波作用和在无超声波作用条件下 ,酸化碘酸钾 (KIO3 )和亚硫酸钠 (Na2 SO3 )反应的反应速率方程式及活化能 ,从而研究该反应的机理以及超声波在该反应中的作用 ,并确定反应的最佳条件。实验得出 ,超声波对该反应有一定的促进作用 ,但是这种促进作用只提高反应的速率常数和降低反应的活化能 ,并没有改变反应机理。在超声波功率为 30 0W时 ,反应的速率方程表示式为 :v =k·c1 0 9(KIO3 ) ·c1 0 0 (Na2 SO3 )·c1 0 8(H+ ) ,其中 :k =95 0 (mol-1·L) 2 ·s-1,活化能为 17 35kJ·mol-1。实验还得出 ,在温度为2 98K时 ,当KIO3 与Na2 SO3 的初始浓度比为 2∶5 ,H+ 的初始浓度为 0 0 4 2 8mol·L-1,超声功率为 30 0W时 ,反应速率为最快 ,即v =4 31× 10 -4mol·L-1·s-1)。     

Sodium current of neurosecretory cells in the eyestalk from the shrimp Penaeus japonicus

The properties of the inward current of medulla terminalis-X-organ (MTXO) cells isolated from the Penaeus japonicus eyestalk were studied with the whole-cell clamp technique in the presence of Ca²⁺ and K⁺ channel blockers. The inward currents had a threshold at about −50 mV and peaked at −10 mV. The reversed potential (V_rev) was very close to V_Na, the theoretical Nernst equilibrium potential for Na⁺. V_rev followed V_Na when the external Na⁺ concentration was varied and the currents were entirely suppressed by 30 nM tetrodotoxin (TTX), indicating that it was carried by Na⁺. The smooth line of concentration-dependent inhibition of sodium currents by TTX represented the best fit with the Hill equation, yielding an IC₅₀ of 2.1 ± 0.1 nM. The values of the half-maximal activation voltage V_h were −20.6 ± 0.5 and −19.3 ± 0.5 mV, respectively, in the absence and presence of 2 nM TTX. TTX had no significant effect on the voltage dependence of steady-state activation and inactivation of I_Na. Taken together, the results suggest that the inward current recorded under our experimental conditions was carried by sodium ions flowing through fast voltage-dependent Na⁺ channels.     

The short C-terminal hydrophilic domain of NhaH Na^＋/H^＋ antiporter from Halobacillus dabanensis with roles in resistance to salt and in pH sensing

The Na^＋/H^＋ antiporter plays key roles in maintaining low cytoplasmic NaNa^＋ level and pH homeostasis, while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters. In our previous study, the first Na^＋/H^＋ antiporter gene nhaH from moderate halophiles was cloned from Halobacillus dabanensis D-8 by functional complementation. A topological model suggested that only nine amino acid residues （^395PLIKKLGMI403） existed in the hydrophilic C-terminal domain of NhaH. The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH△C. Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid residues significantly inhibited the complementation ability of E. coil KNabc, in which three main Na^＋/H^＋ antiporters nhaA, nhaB and chaA were deleted. Everted membrane vesicles prepared from E. coil KNabc/nhaHAC decreased both Na^＋/H^＋ and Li^＋/H^＋ exchange activities of NhaH, and also resulted in an acidic shift of its pH profile for Na^＋, indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.