Specificities of monoclonal and polyclonal antibodies that inhibit adsorption of herpes simplex virus to cells and lack of inhibition by potent neutralizing antibodies.

Polyclonal and monoclonal antibodies to individual herpes simplex virus (HSV) glycoproteins were tested for ability to inhibit adsorption of radiolabeled HSV type 1 (HSV-1) strain HFEMsyn [HSV-1(HFEM)syn] to HEp-2 cell monolayers. Polyclonal rabbit antibodies specific for glycoprotein D (gD) or gC and three monoclonal mouse antibodies specific for gD-1 or gC-1 most effectively inhibited HSV-1 adsorption. Antibodies of other specificities had less or no inhibitory activity despite demonstrable binding of the antibodies to virions. Nonimmune rabbit immunoglobulin G and Fc fragments partially inhibited adsorption when used at relatively high concentrations. These results suggest involvement of gD, gC, and perhaps gE (the Fc-binding glycoprotein) in adsorption. The monoclonal anti-gD antibodies that were most effective at inhibiting HSV-1 adsorption had only weak neutralizing activity. The most potent anti-gD neutralizing antibodies had little effect on adsorption at concentrations significantly higher than those required for neutralization. This suggests that, although some anti-gD antibodies can neutralize virus by blocking adsorption, a more important mechanism of neutralization by anti-gD antibodies may be interference with a step subsequent to adsorption, possibly penetration.     

趋磁细菌培养及用于吸附分离贵重金属离子

生物吸附是有效处理含较低浓度重金属离子废水的廉价方法之一。本文通过对污水处理厂活性污泥的富集和培养, 经过分离、纯化活性污泥中的细菌, 最终得到了趋磁细菌MTB-11s。通过16S rDNA鉴定, 菌株MTB-11s属于代尔夫特菌属。对趋磁细菌的生物吸附性能进行了研究, 实验结果表明, 趋磁细菌MTB-11s对不同金属离子具有选择吸附特性, 其对银离子的吸附表现为快速过程, 温度对其吸附性能的影响较小, pH值为4?8时吸附率较高; 随着干菌浓度的增加, 吸附率不断升高, 最终趋于平稳; 随着银离子初始浓度的增加, 吸附率呈现先升高后降低的趋势。在菌量充足或金属离子浓度较低时, 铜、钴离子的存在能促进银离子的吸附, 其他范围则表现为竞争吸附。     

Specificity of virus adsorption to clay minerals

Competitive adsorption studies indicated that reovirus type 3 and coliphage T1 did not share common adsorption sites on kaolinite and montmorillonite. Compounds in the minimal essential medium (e.g., fetal bovine serum, amino acids) in which the reovirus was maintained blocked adsorption of coliphage T1 to kaolinite and partially to montmorillonite in synthetic estuarine water, but they had no effect on coliphage adsorption to montmorillonite in distilled water or on the adsorption of the reovirus to either clay. The blockage of positively charged sites on kaolinite or montmorillonite by treatment of the clays with sodium metaphosphate or with the supernatants from montmorillonite or kaolinite, respectively, had no effect on adsorption of the reovirus. These data indicate that there was a specificity in adsorption sites for mixed populations of reovirus type 3 and coliphage T1 and emphasize the importance of using more than one type of virus, especially in combination, to predict virus behavior (e.g., adsorption, loss of infectivity) in soils and sediments containing clay minerals.     

Removal of selected metal ions from aqueous solution using modified corncobs

The objective of this study was to convert corncobs to metal ion adsorbents for wastewater treatment. Ground corncobs were modified with either 0.6 M citric acid (CA) or 1.0 M phosphoric acid (PA) to help improve their natural adsorption capacity. The effect of a combination of wash and modification treatment was tested for corncob adsorption efficiency with five different metal ions (cadmium, copper, lead, nickel, zinc) individually or in a mixed solution containing each metal at a 20 mM concentration. Results were compared to those of commercial resins Amberlite IRC-718, Amberlite 200, Duolite GT-73 and carboxymethylcellulose (CMC). Modified corncobs showed the same adsorption efficiency as Duolite GT-73 for cadmium, copper, nickel and zinc ions and had greater adsorption than CMC for nickel and zinc ions. For mixed metals, the modified corncobs exhibited the same adsorption efficiency as Duolite GT-73 for cadmium and copper ions and the same or higher adsorption than Amberlite IRC-718 for lead ions. Adsorption capacities of modified samples were compared to those of Amberlite IRC-718, Amberlite 200 and Duolite GT-73. Commercial resins generally had higher adsorption capacities than modified corncobs. However, the adsorption capacity of modified corncobs for copper and lead ions was equivalent to Duolite GT-73, but was lower than for Amberlite IRC-718 or Amberlite 200. Depending on the specific metal ion and the presence or absence of other metal ions, chemically modified corncobs were at least equivalent in adsorption properties to all of the commercial cation exchange resins examined in this study.     

Thermodynamics of statherin adsorption onto hydroxyapatite

Statherin is a salivary protein that inhibits the nucleation and growth of hydroxyapatite crystals in the supersaturated environment of the oral cavity. The thermodynamics of adsorption of statherin onto hydroxyapatite crystals have been characterized here by isothermal titration calorimetry and equilibrium adsorption isotherm analysis. At 25 degrees C, statherin adsorption is characterized by an exothermic enthalpy of approximately 3 kcal/mol that diminishes to zero at approximately 25% surface coverage. The initial heat of statherin adsorption increases with temperature, displaying a positive heat capacity change of 194 +/- 7 cal K(-)(1) mol(-)(1) at 25 degrees C. The heat of adsorption during this initial phase is strongly dependent on the buffer species, and from the differential heats of buffer ionization, it can be calculated that approximately one proton is taken up by the crystal or protein upon adsorption. The free energy of adsorption is dominated at all coverages by a large positive entropy (>or=23 cal K(-)(1) mol(-)(1)), which may be partially due to the loss of organized water that hydrates the protein and the mineral surface prior to adsorption. These results are interpreted using a two-site model for adsorption of statherin onto the hydroxyapatite crystals.     

Human palatal saliva: adsorption behaviour and the role of low-molecular weight proteins

In situ ellipsometry was employed to study adsorption from human palatal saliva (HPalS) in terms of dependence on surface wettability and saliva concentration (相似文献   

Adsorption of volatile organic compounds by pecan shell- and almond shell-based granular activated carbons

The objective of this research was to determine the effectiveness of using pecan and almond shell-based granular activated carbons (GACs) in the adsorption of volatile organic compounds (VOCs) of health concern and known toxic compounds (such as bromo-dichloromethane, benzene, carbon tetrachloride, 1,1,1-trichloromethane, chloroform, and 1,1-dichloromethane) compared to the adsorption efficiency of commercially used carbons (such as Filtrasorb 200, Calgon GRC-20, and Waterlinks 206C AW) in simulated test medium. The pecan shell-based GACs were activated using steam, carbon dioxide or phosphoric acid. An almond shell-based GAC was activated with phosphoric acid. Our results indicated that steam- or carbon dioxide-activated pecan shell carbons were superior in total VOC adsorption to phosphoric acid-activated pecan shell or almond shell carbons, inferring that the method of activation selected for the preparation of activated carbons affected the adsorption of VOCs and hence are factors to be considered in any adsorption process. The steam-activated, pecan shell carbon adsorbed more total VOCs than the other experimental carbons and had an adsorption profile similar to the two coconut shell-based commercial carbons, but had greater adsorption than the coal-based commercial carbon. All the carbons studied adsorbed benzene more effectively than the other organics. Pecan shell, steam-activated and acid-activated GACs showed higher adsorption of 1,1,1-trichloroethane than the other carbons studied. Multivariate analysis was conducted to group experimental carbons and commercial carbons based on their physical, chemical, and adsorptive properties. The results of the analysis conclude that steam-activated and acid-activated pecan shell carbons clustered together with coal-based and coconut shell-based commercial carbons, thus inferring that these experimental carbons could potentially be used as alternative sources for VOC adsorption in an aqueous environment.     

Influence of salts on virus adsorption to microporous filters

We investigated the direct and indirect effects of mono-, di-, and trivalent salts (NaCl, MgCl(2), and AlCl(3)) on the adsorption of several viruses (MS2, PRD-1, phiX174, and poliovirus 1) to microporous filters at different pH values. The filters studied included Millipore HA (nitrocellulose), Filterite (fiberglass), Whatman (cellulose), and 1MDS (charged-modified fiber) filters. Each of these filters except the Whatman cellulose filters has been used in virus removal and recovery procedures. The direct effects of added salts were considered to be the effects associated with the presence of the soluble salts. The indirect effects of the added salts were considered to be (i) changes in the pH values of solutions and (ii) the formation of insoluble precipitates that could adsorb viruses and be removed by filtration. When direct effects alone were considered, the salts used in this study promoted virus adsorption, interfered with virus adsorption, or had little or no effect on virus adsorption, depending on the filter, the virus, and the salt. Although we were able to confirm previous reports that the addition of aluminum chloride to water enhances virus adsorption to microporous filters, we found that the enhanced adsorption was associated with indirect effects rather than direct effects. The increase in viral adsorption observed when aluminum chloride was added to water was related to the decrease in the pH of the water. Similar results could be obtained by adding HCl. The increased adsorption of viruses in water at pH 7 following addition of aluminum chloride was probably due to flocculation of aluminum, since removal of flocs by filtration greatly reduced the enhancement observed. The only direct effect of aluminum chloride on virus adsorption that we observed was interference with adsorption to microporous filters. Under conditions under which hydrophobic interactions were minimal, aluminum chloride interfered with virus adsorption to Millipore, Filterite, and 1MDS filters. In most cases, less than 10% of the viruses adsorbed to filters in the presence of a multivalent salt and a compound that interfered with hydrophobic interactions (0.1% Tween 80 or 4 M urea).     

Adsorption of recombinant human bone morphogenetic protein rhBMP-2m onto hydroxyapatite

Recombinant human mature bone morphogenetic protein 2 (rhBMP-2m) has been expressed to study its adsorption onto precipitated hydroxyapatite (HA). The influence on the adsorption process of different parameters such as pH and concentrations of calcium, phosphate or NaCl has been investigated. Although the adsorption proceeds rapidly at the initial stages, the maximum adsorbed amount is reached after four hours. The process is notably influenced by adding calcium or phosphate to the system but, while calcium ions increase the adsorption of rhBMP-2m onto HA, phosphate ions inhibit it. The influence of pH and NaCl concentration are notable but less important than those of calcium and phosphate. The adsorption data fit well to a Langmuir adsorption isotherm. The values of the isotherm parameters have been calculated and discussed, and an adsorption mechanism has been proposed.     

Adsorption of ionized and neutral pentachlorophenol to phosphatidylcholine membranes

We have studied adsorption of pentachlorophenol (PCP) to phosphatidylcholine (PC) membranes by measuring the electrophoretic mobility of multilayered lipid vesicles in PCP solutions. PC vesicles become negatively charged due to the adsorption of ionized PCP, and we have found that their zeta potential depends upon the ionic strength and pH of the aqueous suspension. We have shown that the experimental results can be adequately accounted for in terms of a two-component Langmuir-Stern-Grahame adsorption model assuming that the 'PCP adsorption sites' are occupied either by the neutral (HA) or the ionized (A-) species. The characteristics of adsorption isotherms of the PCP - PC membrane are as follows: the association constants are KA = 55,000 dm3/mol, KHA = 279,000 dm3/mol; 4.3 PC molecules make up each PCP adsorption site at saturation; the linear partition coefficients are beta HA = (15.5 +/- 0.7) x 10(-5) m and beta A = (3.0 +/- 0.3) x 10(-5) m. The properties of PCP adsorption isotherms for PC membranes predict an increased pKa value of membrane-bound PCP, which has been observed in related studies.     

Modification of cellulose films by adsorption of CMC and chitosan for controlled attachment of biomolecules

The adsorption of human immunoglobulin G (hIgG) and bovine serum albumin (BSA) on cellulose supports were investigated. The dynamics and extent of related adsorption processes were monitored by surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation monitoring (QCM-D). Amine groups were installed on the cellulose substrate by adsorption of chitosan from aqueous solution, which allowed for hIgG to physisorb from acid media and produced a functionalized substrate with high surface density (10 mg/m(2)). hIgG adsorption from neutral and alkaline conditions was found to yield lower adsorbed amounts. The installation of the carboxyl groups on cellulose substrate via carboxymethylated cellulose (CMC) adsorption from aqueous solution enhanced the physisorption of hIgG at acidic (adsorbed amount of 5.6 mg/m(2)) and neutral conditions. hIgG adsorption from alkaline conditions reduced the surface density. BSA was used to examine protein attachment on cellulose after modification with chitosan or carboxymethyl cellulose. At the isoelectric point of BSA (pI 5), both of the surface modifications enhanced the adsorption of this protein when compared to that on unmodified cellulose (a 2-fold increase from 1.7 to 3.5 mg/m(2)). At pH 4, the electrostatic interactions favored the adsorption of BSA on the CMC-modified cellulose, revealing the affinity of the system and the possibility of tailoring biomolecule binding by choice of the surface modifier and pH of the medium.     

A Review of Molybdenum Adsorption in Soils/Bed Sediments: Speciation,Mechanism, and Model Applications

Mo is an essential trace element for both plants and animals in low concentrations (<5 ppm). However, provoked by uncontrolled industrial waste releases in freshwater or seawater, it is plausible that excessive availability of soluble Mo(VI) would be potentially toxic. In the environment, soluble Mo(VI) is mainly present in anionic forms of molybdate (MoO₄ ^2?) and/or tetrathiomolybdate (MoS₄ ^2?). The fate and transport of soluble Mo(VI) anions in surface and subsurface aquatic environments is typically controlled by adsorption in acidic soils and sediment. As such, the ability of soils/bed sediments to retain Mo(VI) is a key to determine its general mobility in the aquatic environment. This article reviews the sources and distribution of Mo speciation in solution and Mo(VI) anions adsorption mechanisms in soils and bed sediments, and evaluates the surface adsorption complexation models at the solid-water interface to estimate Mo(VI) anions adsorption in these chemical systems. Mo(VI) anions adsorption mechanisms included MoO₄ ^2? and MoS₄ ^2? adsorption by several prevailing adsorbent contents (including clay, Fe, Al oxides, iron sulfide, manganese oxides, and organic matter) of soils and bed sediments, and the influence of the competitive adsorption of other anions (e.g., sulfate, selenate, phosphate, arsenate, silicate, or tungstate). Models to estimate Mo(VI) anions adsorption include the triple layer model (TLM), the diffuse layer model (DLM), the constant capacitance surface complexation model (CCM), and charge distribution multisite complexation model (CD-MUSIC).     

Effects of solution chemistry and aging time on prion protein adsorption and replication of soil-bound prions

Prion interactions with soil may play an important role in the transmission of chronic wasting disease (CWD) and scrapie. Prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. We investigated HY TME prion protein (PrP(Sc)) adsorption to soil minerals in aqueous solutions of phosphate buffered saline (PBS), sodium chloride, calcium chloride, and deionized water using western blotting. The replication efficiency of bound prions following adsorption in these solutions was also evaluated by protein misfolding cyclic amplification (PMCA). Aging studies investigated PrP(Sc) desorption and replication efficiency up to one year following adsorption in PBS or DI water. Results indicate that adsorption solution chemistry can affect subsequent prion replication or desorption ability, especially after incubation periods of 30 d or longer. Observed effects were minor over the short-term (7 d or less). Results of long-term aging experiments demonstrate that unbound prions or prions bound to a diverse range of soil surfaces can readily replicate after one year. Our results suggest that while prion-soil interactions can vary with solution chemistry, prions bound to soil could remain a risk for transmitting prion diseases after months in the environment.     

Elimination of nonspecific adsorption of serum proteins by Sepharose-bound antigens.

Nonspecific adsorption of serum proteins occurs with immunoadsorption of antibodies on Sepharose-myoglobin and Sepharose-staphylococcal nuclease immunoadsorbents. This adsorption results from nonspecific hydrophobic and ionic interactions between these serum proteins and the immunoadsorbents. Various preelution washing procedures were examined, and only borate-saline buffer (pH 8,5) containing a nonionic detergent, Tween 20 (0,1%), and a high salt concentration (1 m NaCl) eliminated or significantly reduced nonspecific adsorption without appreciably diminishing the recovery of specifically adsorbed antibodies.     

Nutrient depletion modifies cell wall adsorption activity of wine yeast

Yeast cell wall is a structure that helps yeasts to manage and respond to many environmental stresses. The mannosylphosphorylation is a modification in response to stress that provides the cell wall with negative charges able to bind compounds present in the environment. Phenotypes related to the cell wall modification such as the filamentous growth in Saccharomyces cerevisiae are affected by nutrient depletion. The present work aimed at describing the effect of carbon and/or nitrogen limitation on the aptitude of S. cerevisiae strains to bind coloured polyphenols. Carbon- and nitrogen-rich or deficient media supplemented with grape polyphenols were used to simulate different grape juice conditions—early, mid, ‘adjusted’ for nitrogen, and late fermentations. In early fermentation condition, the R+G+B values range from 106 (high adsorption, strain Sc1128) to 192 (low adsorption, strain Σ1278b), in mid-fermentation the values range from 111 (high adsorption, strain Sc1321) to 258 (low adsorption, strain Sc2306), in ‘adjusted’ for nitrogen conditions the values range from 105 (high adsorption, strain Sc1321) to 194 (low adsorption, strain Sc2306) while in late fermentation conditions the values range from 101 (high adsorption, strain Sc384) to 293 (low adsorption, strain Sc2306). The effect of nutrient availability is not univocal for all the strains and the different media tested modified the strains behaviour. In all the media the strains show significant differences. Results demonstrate that wine yeasts decrease/increase their parietal adsorption activity according to the nutrient availability. The wide range of strain variability observed could be useful in selecting wine starters.     

Removal of chromium(VI) from water and wastewater using surfactant modified coconut coir pith as a biosorbent

Coconut coir pith, an agricultural solid waste was used as biosorbent for the removal of chromium(VI) after modification with a cationic surfactant, hexadecyltrimethylammonium bromide. Optimum pH for Cr(VI) adsorption was found to be 2.0. Reduction of Cr(VI) to Cr(III) occurred to a slight extent during the removal. Langmuir, Freundlich and Dubinin Radushkevich (D-R) isotherms were used to model the adsorption equilibrium data and the system followed all the three isotherms. The adsorption capacity of the biosorbent was found to be 76.3 mg g(-1), which is higher or comparable to the adsorption capacity of various adsorbents reported in literature. Kinetic studies showed that the adsorption obeyed second order and Elovich model. Thermodynamic parameters such as delta G0, delta H0 and delta S0 were evaluated, indicating that the overall adsorption process was endothermic and spontaneous. Effects of foreign anions were also examined. The adsorbent was also tested for the removal of Cr(VI) from electroplating effluent.     

Improvement of bilirubin adsorption capacity of cellulose acetate/polyethyleneimine membrane using sodium deoxycholate

Bilirubin (BR) adsorbents have low removal efficiency because of the tight binding of BR with human albumin (HA) in a complicated blood system. Sodium deoxycholate (SDC) was selected as an adsorption promoter to improve the BR adsorption capacity of a cellulose acetate (CA)/polyethyleneimine (PEI) membrane. Static adsorption experiments show that the maximum BR adsorption capacity of the membrane with SDC in BR–HA mock solution is 100–200% at the molar ratio of SDC to HA ranging from 8 to 12, higher than that without SDC. It is also found that SDC is more efficiently adsorbed by the membrane than BR and HA. Absorption, circular dichroism, and zeta potential studies demonstrate that SDC can be bound with the BR–HA complex to form a ternary BR–HA-SDC_m complex. On the basis, the facilitated adsorption mechanism of BR with SDC was proposed that SDC aggregates or micelles form a quasi-multilayer adsorption on the membrane, increase approachable binding sites, and prolong the distance between the BR–HA complex and the membrane. Thus, SDC as a spacer reduces the influence of the steric hindrance of HA, resulting in an enhanced BR adsorption capacity. Dynamic adsorption results further evidence the facilitated adsorption mechanism.     

脱乙酰魔芋葡苷聚糖对刚果红吸附性能研究

采用静态吸附法研究脱乙酰魔芋葡苷聚糖对刚果红的吸附特性。结果表明,脱乙酰魔芋葡苷聚糖脱色率达92%,吸附速率符合拟二级速率方程,吸附等温线符合Freundlich吸附等温式。根据热力学函数关系计算出吸附焓变(ΔH)为11.033 kJ/mol,为吸热反应,升高温度有利于吸附;且不同温度下的吉布斯自由能变(ΔG)均小于0,表明脱乙酰魔芋葡苷聚糖对刚果红的吸附是自发过程。     

Adsorption of polypeptides on a solid surface. IV. Adsorption and β-structure–coil transition

A theory of adsorption of a polypetide chain capable of undergoing the coil–β-structure transition on a solid planar surface has been developed. The mutual influence of two order–disorder phase transitions, a conformational and an adsorption transition, was investigated. Various types of adsorption transitions are possible, depending on the initial conformational state (partly or completely β-structured) and the selectivity of adsorption: (a) the second-order phase transition, in which the chain is partly structured, both in adsorbed and desorbed states; and (b) the first-order phase transition, in which the chain exhibits a regular β-structure, at least on one side of the adsorption transition boundary. The chain bonding to the surface alters the degree of β-structure, both in the case of selective and nonselective adsorption (similar to the adsorption of the chains with other types of secondary structure). We show that the slope of the adsorption curves for partly β-structural chains increases as a result of an increase in the degree of β-structuring, and this effect is even stronger than the analogous effect of β-structuring.     

铜离子和亚甲蓝在柠檬酸酯化麦草上的吸附行为

以固相酯化法制备一种具有羧基的柠檬酸改性麦草阳离子吸附剂.用批次实验法研究了不同实验条件下(pH值、吸附剂量、吸附质浓度和吸附时间)水溶液中铜离子和亚甲蓝在酯化麦草上的吸附行为.结果表明：溶液初始pH≥40时,铜离子和亚甲蓝达到最大吸附值.≥2.0 g·L^-1的酯化麦草能去除铜浓度为100 mg·L^-1溶液中96%的铜及亚甲蓝浓度为250 mg·L^-1溶液中99%的亚甲蓝.酯化麦草对铜离子和亚甲蓝的吸附符合Langmuir等温模型,其最大吸附能力分别为79.37 mg·g^-1和312.50 mg·g^-1.铜离子和亚甲蓝达到吸附平衡的时间分别为75 min和5 h,准一级和准二级反应动力学方程可分别描述酯化麦草对铜离子和亚甲蓝的吸附过程.