种植碱蓬可使盐性上壤脱盐

种植碱蓬可使盐性上壤脱盐我国耕地中大约有一亿亩为盐碱地,大部分集中于黄淮海平原,盐碱地的综合治理主要以工程技术和生物措施为手段,其中生物措施一项是治理盐碱地的重要环节之一。经研究发现,种植碱蓬可使盐性土壤脱盐,从而起到改良土壤的作用。碱蓬（Ｓｕａｅｄ...     

复合氨基酸电渗析脱盐过程中的动态

本文利用电渗析技术对猪毛水解废液进行脱盐研究以获取很有应用价值的复合氨基酸。重点研究了各种氨基酸在脱盐过程中的变化行为。     

复合氨基酸电渗析脱盐中试研究

在复合氨基酸电渗析脱盐小试研究的基础上又进行了其中试研究,电渗析工艺条件的优化实验采用了先进的陡升法。中试实验过程着重研究了阳极室浓度（Ｃ＿＋）、阴极室浓度（Ｃ＿－）、料液室浓度（Ｃ＿ｄ）、浓缩室浓度（Ｃ＿ｃ）、浓缩室与料液室体积比（Ｖ＿ｃ／Ｖ＿ｄ）以及电流密度（Ⅰ）脱盐率（ＮａＣｌ）、电流效率、能耗（Ｐ）与生产能力（Ｗ）的综合影响,最后确定了中试脱盐工艺的最佳操作条件,同时,给出了最佳操作条件下的氨基酸变化情况。     

种植碱蓬和秸秆覆盖对沿海滩涂极重度盐土盐分动态与脱盐效果的影响

为探明沿海滩涂极重度盐土盐分动态规律及其影响因子,并探讨盐生植被和秸秆覆盖下土壤的脱盐及控盐效果,2014年5月—2015年5月,在江苏沿海滩涂极重度盐土中进行田间试验,设置4种处理:对照(裸地,CK)、种植碱蓬(PS)、15 t·hm^-2秸秆覆盖(SM-A)和30t·hm^-2秸秆覆盖(SM-2A),监测气候因子和土壤盐分的动态变化.结果表明:(1)滩涂裸地表层土壤盐分具有显著的季节性变化特征,表现为在6—8月盐分降低至最低值(8.69g·kg^-1),9—12月呈现积盐作用,最大值为26.66 g·kg^-1;表层土壤盐分变化比亚表层更剧烈,而且亚表层盐分变化相对于表层具有一定的滞后性;(2)相关分析表明,滩涂裸地表层盐分变化与采样前15 d的累积降雨量及蒸降比具有显著的线性关系;多因子及互作逐步分析表明,降雨量增加可以显著促进脱盐作用,大气温度升高可加剧盐分积累,降雨量和大气温度的互作效应增加会对盐分累积产生正效应;(3)PS处理没有显著改变土壤盐分的季节性变化规律,但降低了表层土壤盐分;(4)SM-A和SM-2A条件下,土壤脱盐率与覆盖处理天数回归拟合符合Logistic曲线,且经过雨季覆盖处理90~100 d后表层土壤脱盐率均可达到95.0%以上,覆盖处理120 d后亚表层土壤脱盐率均可达到92.0%以上,之后表层和亚表层土壤盐分分别在0.60和1.00 g·kg^-1以下波动.综合考虑脱盐效果和经济投入,在梅雨季节前(4—5月)采用15 t·hm^-2秸秆覆盖,可能是未来滩涂极重度盐土进行快速脱盐和改良的重要措施.     

高水位区暗管埋设下土壤盐分适时立体调控的生态效应

高水位地区作物生长关键期采用微咸水或咸水灌溉被证明在一定条件下可以起到增产正效应,但同时却存在着土体盐分积累及其对下茬或次年种植影响的生态负效应.为探讨消除或抑制微咸水或咸水灌溉对土壤盐分积累的生态负效应,保证作物种植增产的正效应,本文在河北近滨海高水位盐碱区开展了为期2年的试验研究,探讨了旱季微咸水或咸水灌溉带来的盐分异位积累与离子分布变化特征,分析了雨季关键期暗管适时排盐对土壤盐分的立体调控生态效应.结果表明：旱季咸水灌溉后土壤经历“积盐-脱盐-二次积盐”3个阶段;灌溉初期,1 g·L^-1咸水灌溉处理下0～50 cm土体脱盐,土壤含盐量随土壤深度增加而增加,HCO₃^-含量增加,其他离子含量降低;6与13 g·L^-1咸水灌溉处理下0～50 cm土体积盐,土壤含盐量随土壤深度增加而降低,HCO₃^-含量降低,其他离子含量增加;雨季暗管适时立体调控脱盐效果显著,土壤脱盐率达16.0%～45.7%,同降雨量下,降水分布越集中,脱盐效果越好;周年时间尺度上,咸水灌溉小区土壤积盐量小于对照区;咸水灌溉处理小区冬小麦产量显著高于对照处理,1 g·L^-1 处理高于6与13 g·L^-1处理.     

蔬菜低盐腌制技术的研究进展

综述了低盐腌制蔬菜的研究现状,重点阐述了高盐咸坯脱盐技术和直接低盐腌制技术的研究进展,指出蔬菜低盐腌制技术在现阶段存在的不足,并对其未来的发展前景进行了展望,为低盐腌制蔬菜的研发提供理论借鉴与参考。     

丝素蛋白粉制备工艺研究

用自制脱盐装置研究了高分子丝素蛋白的降解脱盐方法 ,不仅可提高丝素蛋白粉生产效率和收率 ,而且可以起到脱色的作用 ,所得丝素蛋白粉氨基酸含量与原茧丝中的相差不大。喷雾干燥所得粉末颗粒小于冷冻干燥所得粉末颗粒。采用自制脱盐装置和喷雾干燥配合制备丝素蛋白粉是简便可行的     

谷氨酸脱盐废液培养普通小球藻(Chlorella vugaris)C9-JN2010

研究小球藻在谷氨酸脱盐废液中生长,藻细胞组分及废液中营养利用的效果。结果表明:停留时间10 d,小球藻在体积分数为2%脱盐废液中生长最佳,对总糖、总氮及总磷的消耗率分别为99.1%、96.0%和97.0%;细胞干质量、比生长速率和最大生产强度分别为5.60 g/L、0.223 d-1和560.0 mg/(L.d),细胞中粗蛋白质、粗脂肪、粗纤维、粗灰分及总磷含量(以质量百分数计)分别为50.0%±5.0%、10.0%±2.0%、4.0%±0.5%、6.0%±0.5%和0.80%±0.10%。     

淋洗脱盐对滩涂土壤孔隙水重金属垂直迁移的影响

通过淋洗实验,对滩涂土壤在不同脱盐阶段、不同深度的孔隙水重金属含量、土壤氧化还原电位、孔隙水pH 值以及土壤含水率等理化性质进行分析.结果表明:在脱盐过程中,同一盐分梯度孔隙水Cd 、Pb 和Cr 含量从0-10cm 到35-50cm土层都呈现由小到大的垂直分布变化,而从35-50cm 到50-65cm 土层孔隙水Cd 、Pb 和Cr 含量无明显变化;对于不同脱盐阶段土柱,孔隙水Cd 含量分布变化不明显,Pb 含量从高盐分到低盐分呈现由大到小的变化规律.不同处理孔隙水Cr 的平均含量在电导率由7000 μs ·cm-1 到5000 μs ·cm-1 时明显减小,而在5000 μs ·cm-1 以后,含量变化不明显.这一研究结果为治理滩涂土壤重金属污染提供理论依据.     

荒漠盐生植物根际土壤盐分和养分特征

中国西北地区是我国干旱、盐碱化土壤分布面积较广、土壤积盐较重的地区,这里发育着丰富的盐生植物。目前对于干旱荒漠区盐生植物根际特征的研究相对较少,而不同盐生植物的根际特征对于研究盐生植物适应盐渍环境的机制有着重要意义。本研究利采用盆栽根袋法对7种不同类型的荒漠盐生植物的根际盐分和养分特征进行了初步探索。结果表明:盐分在盐生植物根际发生富集,稀盐盐生植物和泌盐盐生植物根际土壤中总盐和8种主要盐分离子的含量都有所增加,而在拒盐盐生植物根际中增加不显著,其中Cl-和Na 的富集程度相对其它6种离子的富集程度要高。稀盐盐生植物和泌盐盐生植物根际土中的SO42-/Cl-比土体有显著的降低,表明在稀盐盐生植物和泌盐盐生植物根际土壤中Cl-的富集程度比SO42-高,拒盐盐生植物根际土盐分SO42-/Cl-比略有提高。7种盐生植物根际土中的Na /K ,Na /Ca2 ,Na /Mg2 比均较土体有显著的增加,芦苇根际土中的增加最小。在所有研究植物中,根际土壤中全N含量比土体的含量高,但全P和全K含量却比土体的含量低;根际土壤中有效态养分的变化则与全态相反,根际土壤中的有效N含量比土体中的都显著降低,除芦苇外,其他六种盐生植物根际土壤中有效P和有效K的含量都高于土体,但有效P的富集不及有效K富集的程度高。在研究的七种植物中,钠猪毛菜根际土壤的有效N亏缺量最高,有效P和速效K富集也最少。7种植物,尤其是稀盐盐生植物和泌盐盐生植物的地上部分的主要盐离子含量比地下部分高,如Cl-、Na 、Ca2 和K ,在根际富集程度最高的Cl-和Na ,在植株的地上部分也增加的最多。     

Boron nitride as desalting material in combination with phosphopeptide enrichment in shotgun proteomics

Hydrophilic peptides in shotgun proteomics have been shown to be problematic in conventional chromatography. Typically, C18 solid phase extraction or peptide traps are used for desalting the sample prior to mass spectrometry analysis, but the capacity to retain hydrophilic peptides is not very high, causing a bias toward more hydrophobic peptides. This is particularly problematic in phosphoproteomic studies. We tested the compatibility of commercially available boron nitride as a novel material for peptide desalting. Boron nitride can be used to recover a wide range of peptides with different physicochemical properties comparable to combined C18 and graphite carbon material.     

Use of desalting gel for the rapid separation of simple sugars from exopolysaccharides produced by lactic acid bacteria

Three methods to remove simple carbohydrates prior to the measurement of exopolysaccharide concentration with the phenol/sulphuric acid method were compared. A new method based on size exclusion chromatography on a desalting gel compared favourably with ethanol precipitation (which was simple and rapid, but resulted in underestimation of EPS concentration) and dialysis (which was long and cumbersome). © Rapid Science Ltd. 1998     

A simple desalting method for direct MALDI mass spectrometry profiling of tissue lipids

Direct MALDI-mass spectrometry (MALDI-MS) profiling of tissue lipids often observes isobaric phosphatidylcholine (PC) species caused by the endogenous alkali metal ions that bias the relative abundance of tissue lipids. Fresh rat brain cryosections were washed with 70% etha­nol (EtOH), water (H₂O), or 150 mM ammonium acetate (NH₄Ac), and the desalting effectiveness of each fluid was evaluated by MALDI-MS profiling of PC and sphingomyelin (SM) species in tissue and in the washing runoff. The results indicated that EtOH and H₂O only partially desalted the tissue lipids, yet both substantially displaced the tissue lipids to the washing runoffs. On the other hand, NH₄Ac effectively desalted the tissue lipids and produced a runoff containing no detectable PCs or SMs. NH₄Ac wash also unveiled the underlying changes of PCs and SMs in the infarcted rat cortex previously masked by edema-caused increase of tissue sodium. The MS/MS of an isobaric PC in the infarcted cortex revealed the precursor change as the result of NH₄Ac wash and confirmed the desalting effectiveness of such wash. Other than desalting, NH₄Ac wash also removes contaminants in tissue, enhances the overall spectral quality, and benefits additionally in profiling of biological molecules in tissue.     

The use of spin desalting columns in DMSO‐quenched H/D‐exchange NMR experiments

Dimethylsulfoxide (DMSO)‐quenched hydrogen/deuterium (H/D)‐exchange is a powerful method to characterize the H/D‐exchange behaviors of proteins and protein assemblies, and it is potentially useful for investigating non‐protected fast‐exchanging amide protons in the unfolded state. However, the method has not been used for studies on fully unfolded proteins in a concentrated denaturant or protein solutions at high salt concentrations. In all of the current DMSO‐quenched H/D‐exchange studies of proteins so far reported, lyophilization was used to remove D₂O from the protein solution, and the lyophilized protein was dissolved in the DMSO solution to quench the H/D exchange reactions and to measure the amide proton signals by two‐dimensional nuclear magnetic resonance (2D NMR) spectra. The denaturants or salts remaining after lyophilization thus prevent the measurement of good NMR spectra. In this article, we report that the use of spin desalting columns is a very effective alternative to lyophilization for the medium exchange from the D₂O buffer to the DMSO solution. We show that the medium exchange by a spin desalting column takes only about 10 min in contrast to an overnight length of time required for lyophilization, and that the use of spin desalting columns has made it possible to monitor the H/D‐exchange behavior of a fully unfolded protein in a concentrated denaturant. We report the results of unfolded ubiquitin in 6.0M guanidinium chloride.     

Concentration and desalting of peptide and protein samples with a newly developed C18 membrane in a microspin column format.

Protein identification plays an important role in today's academic and industrial proteomic research. Commonly used methods for the separation of proteins from complex samples include liquid chromatography (e.g., ion exchange, reversed-phase, hydrophobic interaction), or types of gel electrophoresis (e.g., 1d and 2d PAGE). Relevant proteins separated in the latter way are often cut out, cleaved with trypsin "in gel," and the resulting peptide mixtures combined with matrix and spotted onto a target plate for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-ms) analysis. Subsequently, proteins can be identified by comparison of the resulting peptide mass fingerprints against different databases.(1) since the success of protein identification can be enhanced by the desalting and concentration of the samples, an innovative C18-membrane was incorporated into a microspin column (Vivapure C18 micro spin column, Vivascience AG, Hannover, Germany) to analyze its performance for sample preparation prior to MALDI-ToF-ms. Rapid concentration of single or multiple 200-microl volumes through an available membrane only 2 mm in diameter allowed for analysis of very dilute samples. We observed the successful and rapid desalting of urea-containing protein samples at 100 fmol/mul up to a mass of approximately 70 KDA and the concentration of digest peptides from a solution of 1 fmol/microl using C18-membrane technology.     

A general approach to desalting oligosaccharides released from glycoproteins

Desalting of sugar samples is essential for the success of many techniques of carbohydrate analysis such as mass spectrometry, capillary electrophoresis, anion exchange chromatography, enzyme degradation and chemical derivatization. All desalting methods which are currently used have limitations: for example, mixed-bed ion-exchange columns risk the loss of charged sugars, precipitation of salt by a non-aqueous solvent can result in co-precipitation of oligosaccharides, and gel chromatography uses highly crosslinked packings in which separation of small oligosaccharides is difficult to achieve. We demonstrate that graphitized carbon as a solid phase extraction cartridge can be used for the purification of oligosaccharides (or their derivatives) from solutions containing one or more of the following contaminants: salts (including salts of hydroxide, acetate, phosphate), monosaccharides, detergents (sodium dodecyl sulfate and Triton X-100), protein (including enzymes) and reagents for the release of oligosaccharides from glycoconjugates (such as hydrazine and sodium borohydride). There is complete recovery of the oligosaccharides from the adsorbent which can also be used to fractionate acidic and neutral glycans. Specific applications such as clean-up of N-linked oligosaccharides after removal by PNGase F and hydrazine, desalting of O-linked glycans after removal by alkali, on-line desalting of HPAEC-separated oligosaccharides and -eliminated alditols prior to electrospray mass spectrometry, and purification of oligosaccharides from urine are described.     

Silicone/graphite coating for on-target desalting and improved peptide mapping performance of matrix-assisted laser desorption/ionization-mass spectrometry targets in proteomic experiments

In two-dimensional gel electrophoresis-based proteomic experiments matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) peptide mass fingerprinting is often the technique of choice in identifying proteins. Here, we present a novel surface coating technique for MALDI-MS targets that improves manual and automatic sample analysis. A mixture of silicone and graphite is spread in the form of a thin layer over the target. Due to the hydrophobicity of the coating, aqueous solutions can be applied to relatively small spots very precisely using a robotic system. At least four times more liquid can be concentrated on the same area compared to uncoated steel targets. alpha-cyano-4-hydrocinnamic acid crystallizes in form of very small crystals evenly distributed over the surface. The search for "hot spots" during the analysis is not necessary, which supports the automatic acquisition of data. The homogeneous crystal layer can be very effectively washed on-target without encountering major sample losses. This efficient washing and the focused application of aqueous samples replace expensive and time-consuming reversed phase micro column based sample clean-ups. When analyzing peptide mixtures, the signal intensities are up to five times higher than with preparations of the same un-desalted samples on steel targets, since four times more sample can be loaded. The mass resolution remains unaffected by the surface coating. After usage the coating can be removed, followed by a new coating avoiding any carry-over of sample to the next analysis. All these properties make the precoating of MALDI-MS targets with a silicone/graphite layer an ideal technique for routine analysis in large-scale proteomic experiments.     

Microcentrifuge desalting: a rapid, quantitative method for desalting small amounts of protein

A mass fragmentographic method for the determination of unconjugated homovanillic acid, vanilmandelic acid, and 3-methoxy-4-hydroxyphenylethylene glycol in serum, using deuterated internal standards, is described. Reference values for normal healthy adults were 11.3 + 4.2. μg/liter (homovanillic acid), 5.9 + 2.2 μg/liter (vanilmandelic acid), and 3.3 ± 1.3 μg/liter (3-methoxy-4-hydroxyphenylethylene glycol). Samples obtained from children were found to contain statistically higher values. The clinical importance of these measurements in diseases such as neuroblastoma, pheochromocytoma, Parkinsonism treated with l-3,4-dihydroxyphenylalanine, and renal failure is discussed in relation to the reference values mentioned above and the levels of homovanillic acid and vanilmandelic acid in urine.