Affinity adsorption of recombinant human interferon-α on a porous dye-affinity adsorbent

Interferons are potent biologically active proteins synthesized and secreted by somatic cells of all mammalian species. Dye-affinity adsorption is increasingly used for protein separation. Hollow fibers have several advantages as adsorbents in comparison to conventional bead supports because they are not compressible and they eliminate internal diffusion limitations. The aim of this study was to explore in detail the performance of polyamide hollow fibers to which Cibacron Blue F3GA was attached for adsorption of recombinant interferon-α (rHuIFN-α). The hollow fiber was characterized by scanning electron microscopy. These dye-carrying hollow fibers (35.8 μmol/g) were used in the rHuIFN-α adsorption-elution studies. The effects of initial concentration of rHuIFN-α, medium pH, ionic strength and temperature on the adsorption efficiency of dye-attached hollow fibers were studied in a batch system. The non-specific adsorption of rHuIFN-α on the hollow fibers was 1.2 mg/g. Cibacron Blue F3GA attachment significantly increased the rHuIFN-α adsorption up to 99.8 mg/g. Significant amount of the adsorbed rHuIFN-α (up to 94.8%) was eluted in 1 h in the elution medium containing 1.0 M NaCl. In order to determine the effects of adsorption conditions on possible conformational changes of rHuIFN-α structure, fluorescence spectrophotometry was employed. We resulted that dye-affinity hollow fibers can be applied for rHuIFN-α adsorption without causing any significant conformational changes. Repeated adsorption/elution processes showed that these dye-attached hollow fibers are suitable for rHuIFN-α adsorption.     

Production of Recombinant Porcine Interferon alpha Using PHB–Intein-Mediated Protein Purification Strategy

Interferons (IFNs) are involved in the pathogenesis and recovery of viral and other infectious diseases. Recombinant IFNs have been used as anti-infectious agents exhibiting a broad range of antiviral and immunomodulatory properties in both human and domestic animals. In this report, we describe a highly efficient and economical approach to purify porcine IFN alpha (PoIFNα) using polyhydroxybutyrate (PHB) as the affinity carrier and intein for self-cleaving removal of the affinity tag. Additionally, the conditions of protein expression and purification have been optimized. Our results suggested that culture medium containing 1.62% (w/v) of sodium lactate dramatically increases the accumulation of PHB binding protein in Escherichia coli cells. High yields of recombinant PoIFNα (30–35 mg/L, 97% purity by high-performance liquid chromatography) were obtained using intein-mediated self-cleaving conditions using a cleavage-inducing buffer with a pH of 6.5 at 20 °C for 24–36 h. The antiviral activity of the recovered recombinant PoIFNα was up to 1.4 × 10⁶ IU/mg of protein ascertained using recombinant human IFNα1 as a standard. This report also demonstrates that large-scale production of intein-mediated purification of highly pure and active recombinant PoIFNα is feasible for the purposes of experimental studies, veterinary clinic therapeutics, and swine infectious disease control.     

Identification of the polymorphisms in IFITM3 gene and their association in a Korean population with ulcerative colitis

Interferons play critical roles in tumor pathogenesis by controlling apoptosis and through cellular anti-proliferative and differentiation activities. Interferon inducible transmembrane protein (IFITM) family genes have been implicated in several cellular processes such as the homotypic cell adhesion functions of IFN and cellular anti-proliferative activities. Expression levels of IFITM genes have been found to be up-regulated in gastric cancer cells and colorectal tumors. IFITM3 (also known as 1-8U) is a member of the IFITM family, and has been described as a key player in specification of germ cell fate. IFITM3 was first isolated from a genetic screen aimed at identifying genes involved in acquisition of germ cell competence. It has been proposed that epiblast cells have the highest expression of IFITM3 initiated germ cell specification and that homotypic association can discriminate germ cells from their somatic neighbors. In an attempt to better understand the genetic influences of IFITM3 on ulcerative colitis, we have identified possible variation sites and single nucleotide polymorphisms (SNPs) through two exons and their boundary IFITM3 intron sequences including the ~2.1 kb promoter regions. To determine whether or not these IFITM3 SNPs are associated with susceptibility to ulcerative colitis, frequencies of the genotype and allele of IFITM3 polymorphisms were analyzed on genomic DNAs isolated from patients with ulcerative colitis and from healthy controls. We also investigated the haplotype frequencies constructed by these SNPs in both groups. In this study, we also showed that expression level of IFITM3 mRNA was significantly higher in tissues of the ileum and cecum of the digestive system. We identified a total of seven SNPs and multiple variation regions in the IFITM3 gene. The genotype frequency of the g.-204T>G polymorphism in patients with ulcerative colitis was significantly different from that of the control group. Our results strongly suggest that polymorphisms of the IFITM3 gene may be associated with susceptibility to ulcerative colitis.     

Spectrophotometric determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants

An accurate spectrophotometric method is proposed for the determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants by use of phenoldisulphonic acid. The waste water is filtered through a sintered glass crucible and the PETN is determined in the filtrate and the residue. In the determination of PETN in the filtrate, sodium hydroxide is added and the PETN is extracted with methylene chloride (in alkaline solution, styphnate and TNT are not extracted). The methylene chloride solution is then evaporated to dryness, the residue is treated with a solution of phenoldisulphonic acid in sulphuric acid, water and ammonia are added, and the yellow colour is measured. In the determination of PETN in the residue, the PETN is dissolved in acetone, an aliquot of the acetone solution is treated with water and sodium hydroxide, the PETN is extracted with methylene chloride and the colour is developed as above. Various factors affecting the determination were investigated. The solubility of PETN in water was studied.     

山东省主栽果树生殖器官中稀土与微量营养元素的相关性研究

通过对山东省5大类主栽果树20余个树种的花粉、种子和果实稀土与微量元素自然含量进行分析比较, 认为稀土(RE)与微量元素在各树种花粉中平均含量顺序为Fe＞Zn＞B＞Cu＞Mn＞RE, 种子中B＞Fe＞Zn＞Mn＞Cu＞RE, 果实中Fe＞B＞Zn＞Cu＞Mn＞RE. 各元素在各生殖器官中的自然分布因树种而有很大差异. 但基本规律类同, 即花粉＞种子＞果实. 花粉富集各种微量营养元素的能力都很强. 花粉和果实稀土与微量元素之间绝大多数呈正相关, 种子大多呈负相关, 但相关性均不显著.     

PP2A in the regulation of cell motility and invasion

Cell motility is a very critical phenomenon that plays an important role in the development of eukaryotic organisms. One of the well studied cell motility phenomena is chemotaxis, which is described as a directional movement of cell in response to changes in external chemotactic gradient. Numerous studies conducted both in unicellular organism and in mammalian cells have demonstrated the importance of phosphatidylionositol-3 kinase (PI3K) in this process. In addition, it is now well established that although PI3K plays an activation role in chemotaxis, the role of phosphatases is also critical to maintain this dynamic cyclical process. Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase that is a key player in regulating PI3K signaling. PP2A is abundantly and ubiquitously expressed and has been highly conserved during the evolution of eukaryotes. PP2A is composed of three protein subunits, A, B, and C. Subunit 'A' is a 60-65 kDa structural component, 'C' is a 36-38 kDa catalytic subunit, and 'B' is a 54-130 kDa regulatory subunit. The core complex of PP2A is comprised of the A and C subunits, which are tightly associated and this dimeric core complexes with the regulatory B subunit. The B subunit determines the substrate specificity as well as the spatial and temporal functions of PP2A. PP2A plays an important role in regulating multiple signal transduction pathways, including cell-cycle regulation, cell-growth and development, cytoskeleton dynamics, and cell motility. This review focuses on the role of PP2A in regulating motility of normal and transformed cells.     

聚苯胺薄膜电极上示差脉冲伏安法可逆波理论研究

本文提出了聚苯胺(PANI)薄膜电极上示差脉冲伏安法可逆波理论,经验证理论和实验结果相符合.     

Spectrophotometric determination of bismuth in copper and cartridge brass by the iodide method

An improved spectrophotometric method is proposed for the determination with iodide of trace amounts of bismuth in copper and cartridge brass. The sample is dissolved in nitric acid and the bismuth is separated from the copper by an ammoniacal precipitation in the presence of iron(III) hydroxide as a gathering agent. The hydroxide precipitate is dissolved in hydrochloric acid, sulfuric acid is added, the solution is evaporated to a few ml, hydrobromic acid is added to volatilize the antimony and tin, and the solution is evaporated to fumes of sulfuric acid. The bismuth iodide color is then developed with a composite potassium iodide—sodium hypophosphite reagent. Factors affecting the bismuth iodide color are investigated.     

Stress studies on acyclovir

Acyclovir is an antiviral drug of choice in the treatment of many types of herpes virus infections, including genital herpes simplex infections, herpetic conjunctivitis, herpes simplex encephalitis, etc. The present study describes the degradation behavior of acyclovir under different International Conference on Harmonization recommended stress conditions (hydrolysis, oxidation, photolysis, and thermal decomposition) in order to establish a validated stability-indicating high-performance liquid chromatography method. Acyclovir is found to degrade extensively in acidic conditions and oxidative stress. Mild degradation of the drug occurs in alkaline and neutral conditions. The drug is stable to dry heat. The drug is found to be sufficiently stable after light exposure in a solid state; however, photolytic degradation is observed when the drug is exposed as a solution in water. The major degradation product in acidic hydrolysis and photolysis is identified as guanine through comparison with the standard. Separation of drug and the degradation products under various conditions is successfully achieved on a C-18 column utilizing water-methanol in the ratio of 90:10. The flow rate is 1 mL/min, and the detection wavelength is 252 nm. The method is validated with respect to linearity, precision, accuracy, selectivity, specificity, and robustness. The mean values of slope and correlation coefficient are 39.307 and 0.9998 with relative standard deviation values less than 2%. The recovery of the drug is found to be in the range of 97.34% to 102.35%. From the previous study it is concluded that the stability-indicating method developed for acyclovir can be used for analysis of the drug in various stability samples.     

Adsorption and structure of hydrocarbons in MCM-41: a computational study

The adsorption of linear, branched, and cyclic hydrocarbons in MCM-41 is studied using Configurational Bias Monte Carlo simulations. A new computational model for MCM-41 is proposed which, although simple, is able to predict adsorption isotherms which are in agreement with the scarce experimental data. The structure of the adsorbed phase is analyzed and found to be similar to that of studies using small, hard spheres trapped in pores. The adsorption of mixtures is investigated, and the adsorption hierarchy is discussed. The structure of the adsorbed mixture is revealed and shows that all components of the mixture exhibit structure, even if they are only adsorbed in small quantities. Finally, the model is modified to include surface roughness and the effect on the adsorption isotherms and structure of the adsorbed phase is discussed.     

五羰基合铁分子化学键特性的研究

We have found from experimental data that, in the iron pentacarbonyl molecule, the length of Fe-C bond in axial is shorter than that in planar, but the bond is weaker; the bond distances of C-O of both planar and axial are equal, while the bond strengths are different. This is against the traditional view of “the shorter the bond is, the stronger the bond will be”. We have got through calculation and research, that the main cause of such difference is that the effects of the backdonor of Fe atom′s electrons to C-O bonds in axial and planar are different. The shorter the Fe-C bond is, the more effective the backdonor (or transfer) of electrons is. So that the population between Fe and C in axial are less than those in planar, so the bond is weaker, and the C-O bonds have gained more backdonor electrons than those in planar, thus the bond is stronger.     

A non-linear equilibrium analysis of blowdown policy in pressure—swing—adsorption separation

Using the local non-linear equilibrium approach, we investigated pressure—swing—adsorption (PSA) cycles directed toward the removal of an adsorbable impurity present in large amounts in an inert substance. Three blowdown policies are compared (the blowdown is the part of the PSA cycle in which the pressure of a column is released by rejecting gas). In one such policy, the gas resulting from blowdown is rich in the impurity and is rejected as waste. In a second policy in contrast, the production is adjusted so that the blowdown gas is pure and is considered as a product or is reused to recompress or purge another column. The third policy is intermediate, in the sense that part of the blowdown gas is pure and recovered, and part is impure and rejected.The equilibrium approach presented neglects mass-transfer and dispersion effects, but accounts for non-linear equilibria and variations in gas velocity. It thus allows analytical or semi-analytical expressions to be obtained for quantities such as the inert recovery ratio, and hence an easy qualitative discussion of the effects of operating parameters on the recovery. It is shown that the intermediate policy (partial recovery of the blowdown gas) is optimal. The adsorption of methane and ethane on activated carbon from helium or hydrogen are presented as illustrations.     

Characterization of in vivo metabolites of toad venom using liquid chromatography-mass spectrometry

The structures of in vivo metabolites of marinobufotoxin (marinobufagin 3-suberoylarginine ester), marinobufagin, or bufalin which are typical components of toad venom widely used as the traditional Chinese drug, Ch'an Su, are confirmed using authentic samples based on their liquid chromatography-mass spectrometric behavior. A rat is orally administered 2 mg of the previously mentioned components of toad venom, the serum is collected 30 min after the administration, extracted, and then characterized. Marinobufotoxin is hydrolyzed and further epimerized into 3-epimarinobufagin, but marinobufagin 3-hemisuberate is not detected. After the administration of marinobufagin, 3-epimarinobufagin is detected in both the male and female rats, but marinobufagin 3-sulfate is formed only in the female rats. Bufalin is metabolized to 3-epibufalin, which is found to undergo further conjugation resulting in its 3-glucuronide. Furthermore, 3-epibufalin 3-sulfate is formed only in the female rats.     

Time correlation functions and chemical reaction rates

The relation between time-dependent density correlation functions and chemical reaction rates is investigated. The case of a simple two-atom reaction in a fluid system is studied in detail. It is found that the reaction is obtainable from a three-density correlation function, taken in the long-time, long-wavelength limit. This result is analogous to the well known relation between the diffusion rate and the two-density correlation in a fluid. The present calculation is valid in an arbitrary fluid system, and is applicable in particular to reactions in a catalytic medium.     

Analytical approaches to determination of total choline in foods and dietary supplements

Choline is a quaternary amine that is synthesized in the body or consumed through the diet. Choline is critical for cell membrane structure and function and in synthesis of the neurotransmitter acetylcholine. Although the human body produces this micronutrient, dietary supplementation of choline is necessary for good health. The major challenge in the analysis of choline in foods and dietary supplements is in the extraction and/or hydrolysis approach. In many products, choline is present as choline esters, which can be quantitated individually or treated with acid, base, or enzymes in order to release choline ions for analysis. A critical review of approaches based on extraction and quantitation of each choline ester as well as hydrolysis-based methods for determination of total choline in foods and dietary supplements is presented.     

An improved sealed quartz‐tube method for the determination of hydrogen isotopes in water

Hydrogen stable isotope analysis has been a valuable tool in the fields of geochemistry and ecological research as well as many other research fields. The methods are mainly divided into the dual‐inlet method (off‐line method) and continuous flow method. The dual‐inlet method is complicated and inefficient, but it is still important because of its high precision and wide application range. Although the continuous flow method improves the experimental efficiency, the memory effect is noticeable and the accuracy is reduced. An improved sealed quartz‐tube method is proposed in this paper. The sample is sealed in a capillary tube and placed in a quartz tube containing chromium powder. It is then packaged, evacuated, reacted at a high temperature, and analyzed for hydrogen isotope ratio. Excellent data accuracy, good reproducibility (<1‰), and no memory effect occurred in the method. The process is relatively simple, and the experimental efficiency is greatly improved, which provides an effective method for the analysis of hydrogen isotopes in complex liquid samples.     

哒螨灵在苹果和土壤上残留以及降解行为研究

本研究建立了基于高效液相色谱为基础的哒螨灵分析方法,并对哒螨灵在安徽淮北和陕西咸阳两地苹果上的消解和残留行为进行了研究,同时还考察了哒螨灵在两地土壤中的降解和残留行为．哒螨灵在苹果中的消解动态方程：陕西咸阳为C=0．4007e^-0.1535t,半衰期T1/2=4．5天;安徽淮北=0．1096e^-0.1464t,半衰期T1/2=4．7天;在土壤中的消解动态方程：陕西咸阳为C=0．7978e^0.1218t,半衰期T1/2=5．7天;安徽淮北C=1．4024e^-0.0912t,半衰期T1/2=7．6天．在推荐使用高剂量和推荐高剂量1．5倍情况下,施药1-2次,末次药后7天,哒螨灵在苹果中的残留为0．02～0．14mg／kg;药后14天为0．01—0．12mg／kg．试验结果表明,药后7天,苹果中哒螨灵的残留量低于2mg／kg,用药次数1-2次,每次间隔7天的情况下,在苹果上的安全间隔期可定为7天．     

N,O-羧甲基壳聚糖的合成和性质研究

采用多段升温法将壳聚糖改性,合成了取代度为1.84、平均分子量为3.08×105、等电点为7.28的N,O-羧甲基壳聚糖(CMC),分别用紫外光谱、红外光谱、荧光光谱对其结构进行了表征,并对其水溶液的Zeta电位、电导率、表面张力以及水分散体系中羧甲基壳聚糖微粒的粒径分布进行了研究.结果表明, N,O-羧甲基壳聚糖具有表面活性;介质的pH值和浓度对羧甲基壳聚糖溶液的稳定性有很大的影响.