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101.
A surface modification strategy for the use of giant magnetoresistive materials in the detection of protein-protein interactions is developed. This modification strategy is based on silanization of semiconductive materials. A native silicon nitride surface was treated with concentrated hydrofluoric acid to improve surface homogeneity. Nano-strip was used to oxidize silicon nitride to form a hydrophilic layer. Aminopropyltriethoxysilane was subsequently used to functionalize the treated surfaces to form amine groups, which were further activated with glutaraldehyde to introduce a layer of aldehyde groups. The effectiveness of this modification strategy was validated by chemiluminescence immunoassays of purified 6x His-HrpW of Pseudomonas syringae pv. tomato DC3000 and human transferrin. Signals with intensities related to concentrations of these two immobilized model proteins were observed. The modified surface was also validated by a more complex system: intercellular proteins secreted by DC3000. HrpW in these protein mixtures was successfully recognized by anti-HrpW antibodies when mixed proteins were immobilized onto activated surfaces. This surface modification strategy provides a platform onto which proteins can be directly immobilized for biosensor and protein array applications. 相似文献
102.
Here we report the results of a comprehensive biogeochemical monitoring of Rostherne Mere in 1998, including changes in dissolved oxygen, organic carbon and nitrogen, nitrate/nitrite, ammonia, Al, Na, S, K, Mg, Ca, Si, Fe, Mn, orthophosphate, particulate N & P, suspended solids, temperature, pH, chlorophyll-a and zooplankton. The results demonstrated the major influence of primary producers on the overall geochemical cycling of N, P and Si, and suggested that the significance of zooplankton might have been previously underestimated. For major anions and cations, however, the influence of biota on lake water concentrations appeared to be negligible, reflecting the fact that these chemicals were present far in excess of plankton requirements. Thus changes in concentrations of Ca, K, Na, Mg and S were rather limited and must have reflected changes in hydrological and meteorological parameters. K, however, demonstrated a transitional pattern, reflecting some influence of biological uptake. During the stratification period, the slow processes of bacterial decomposition in the hypolimnion gradually released chemicals contained in the materials accumulated in the bottom layer, remarkably increasing the concentrations of dissolved compounds of those elements present in amounts comparable with the pool stored in the sedimenting detritus (e.g. orthophosphate P, ammonia N, Si and DOC). The decomposition also resulted in a drop in the redox potential, followed by partial denitrification and chemical release from the sediments. The hypolimnion of the Mere was confirmed to remain at the stage of Mn release, characterised by accumulation of DOC, orthophosphates, ammonia and initial stages of denitrification. High levels of P released from the sediments during the stratification period suggest that the lake’s recovery after sewage diversion might be further delayed. 相似文献
103.
104.
To clarify the changes in Si content of diatoms, the particulate silicon (PSi) concentration and total diatom volume (TDV) were determined in Lake Barato, Japan, from April to July 1998–2000. The soluble reactive silicon (SRSi) concentration decreased markedly with the rapid increase in TDV in May and June in all three years, although the value did not fall below that at which diatom growth might be limited. The proliferation of small discoid diatoms contributed to the decrease in SRSi concentration each year. The Si content of diatoms may not be constant as indicated by the changes in PSi:TDV ratio. The low PSi:TDV ratio and the fact that PSi concentration was lower than diatom PSi concentration (calculated from the volume of diatom species) accompanying the decrease in TDV suggests the possibility of a disturbance in the silicification in May and June 1999. These parameter changes accompanying the increase in TDV suggest that the silicification did not catch up with the cell division in early April 1998, early May 1999, and mid-June 2000. In addition, the PSi:TDV ratio increased rapidly and showed large fluctuations in July 1998 and 1999. This may have been caused by a change in dominant species from small discoid diatoms to Aulacoseira granulata because of the differences in Si content per unit cell volume. 相似文献
105.
Xiujuan Jia Royce J. Emerick Henry Kayongo-Male 《Biological trace element research》1997,59(1-3):123-132
A 2 x 2 x 2 factorial experiment was conducted using two dietary levels each (mg/kg of diet) of silicon, 0 and 500; iron,
35 and 187; and ascorbic acid, 0 and 900, to identify biochemical interactions occurring among these nutrients. Supplemental
silicon, in conjunction with the higher dietary-iron level, prevented the plasma-iron decreasing effect observed for the higher
level of iron in the absence of silicon. In the absence of ascorbic acid, silicon also increased iron concentration in the
liver. Lower growth of the silicon and iron-supplemented rats is believed to be a response to a subsequent iron-imposed aberration
of copper or zinc metabolism. This is supported by decreased intestinal metallothionein, increased weights (g/100 g body weight)
of liver, heart, and testes, and decreased packed-cell volume and hemoglobin concentration. The lower plasma-iron level associated
with the higher level of dietary iron appeared to be an expression of the iron-imposed reduction of liver copper stores. Ascorbic
acid decreased plasma-iron concentration and prevented the silicon-related increase in liver iron. 相似文献
106.
Jacek Najda Malgorzata Goss Jan Gmínski Ludmiła Weglarz Krzysztof Siemianowicz Zofia Olszowy 《Biological trace element research》1994,42(1):63-70
The effect of an excessive inorganic silicon oral intake on the activity of basic antioxidant enzymes was studied in rats.
Activities of superoxide dismutase, catalase, and glutathione peroxidase were measured in liver and kidney tissues of animals
receiving per os sodium metasilicate nonahydrate (Na2SiO3.9H2O) (Sigma, [St. Louis, MO]) dissolved in their drinking water. A decrease of the activity of all the studied enzymes was found
in the samples derived from the experimental group. The results obtained indicate the free oxygen radicals participation in
the potential pathologic events in the conditions of systemic hypersilicemia. 相似文献
107.
Hydrophobicity of contact surface induces appressorium formation in Magnaporthe grisea 总被引:5,自引:0,他引:5
Abstract Infection by Magnaporthe grisea , the causal agent of rice blast, requires the formation of a melanized, dome-shaped infection cell, called an appressorium. Little is known about the signals and mechanisms regulating this important developmental process. We have previously observed a correlation between hydrophobicity of the contact surface and appressorium formation. To evaluate this thigmotropic response more precisely, we measured appressorium formation on the surfaces of silicon wafers modified to create various degrees of hydrophobicity. We also examined the effects of artificial ridges created on polystyrene surfaces. Hydrophobic surfaces induced a high level of appressorium formation, whereas hydrophilic surfaces did not. Tips of germ-tubes did not respond to ridges of any particular height, but formed appressoria in a random manner. These results indicate that hydrophobicity of the substratum is a primary determinant and is sufficient to induce appressorium formation in M. grisea . 相似文献
108.
Yutaka Matsuo 《Inorganica chimica acta》2006,359(6):1979-1982
The reaction of [60]fullerene with Me3SiCH2MgCl in 1,2-Cl2C6H4/THF (1/1) under dry air afforded a bis-alkyl adduct, C60(CH2SiMe3)2 (1), in 54% yield. Treatment of 1 with Me3SiCH2MgCl in THF under argon then afforded a trialkyl[60]fullerene, C60(CH2SiMe3)3H (2), in 37% yield. Further treatment of 2 with KOtBu gave a potassium salt, [K(thf)n][C60(CH2SiMe3)3] (3), which was then converted to a Cs-symmetric Rh(I) complex, Rh[η5-C60(CH2SiMe3)3](1,5-cyclooctadiene) (4), in 91% yield. 相似文献
109.
110.
土壤供Si能力及Si与N、P的相互作用 总被引:19,自引:1,他引:18
辽宁地区水田土壤有效Si含量和土壤pH值及粘粒含量呈正相关,和DTPA-Fe含量呈负相关.根据土壤有效Si含量及其有关因素判断土壤供Si能力强弱,发现供Si能力强的土壤主要分布在辽南稻作区及部分中部和辽北稻作区,供Si能力弱的土壤主要分布在东部山地稻作区和辽东稻作区.试验证明Si和N、Si和P之间有相互促进肥效的关系,在N、P、Si适当配比下稻谷产量最高,N、P、Si都影响谷草比,在三者相互作用下,稻谷最高产量出现在谷草比1.0-1.1范围内. 相似文献