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1.
Immobilization of catalase (molecular weight 240,000 daltons) in polyelectrolyte microspheres was studied. The microspheres were obtained by alternating adsorption of dextran sulfate and protamine on commercially available melamine formaldehyde cores followed by the core hydrolysis at pH 1.7. As the interior of the microspheres was filled with homogeneous matrix, the catalase distribution inside the microspheres was uniform. The quantity of entrapped catalase was dependent on the initial concentration of the enzyme and pH of solution, and the peak value was 10(8)-10(9) molecules per microsphere. It was demonstrated that catalase was entrapped in the microspheres via electrostatic and hydrophobic interactions. The catalase activity inside the microspheres increased as the quantity of enzyme decreased, which was due to the switch between diffusion and kinetic regimes of the enzymatic reaction. The microspheres could be applied for separation and concentration of high molecular weight proteins. 相似文献
2.
Bruno Sarmento Susana Martins António Ribeiro Francisco Veiga Ronald Neufeld Domingos Ferreira 《International journal of peptide research and therapeutics》2006,12(2):131-138
The overall objective of our research is to produce polyanion/chitosan nanoparticulate oral delivery systems for insulin. Specific objectives of the present study were to study dextran sulfate or alginate complexation with chitosan on mean particle size, insulin association efficiency, loading capacity and release profile. Nanoparticles were formed by ionotropic complexation and coacervation between polyanions (dextran sulfate and alginate) and chitosan. Diameter was evaluated with photon correlation spectroscopy, polymer interaction was confirmed by DSC and FTIR and particle morphology was assessed by SEM and TEM. Mean nanoparticle diameter ranged from 423 to 850 nm, insulin association efficiency from 63 to 94% and loading capacity from 5 to 13%. Dextran sulfate provided highest insulin association efficiency and retention of insulin in gastric simulated conditions. These nanoparticle systems show promise as insulin and potentially other therapeutic polypeptides carriers. 相似文献
3.
T. N. Borodina L. D. Rumsh S. M. Kunizhev G. B. Sukhorukov G. N. Vorozhtsov B. M. Feldman E. A. Markvicheva 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2008,2(1):88-93
Based on the method of the layer-by-layer (LbL) adsorption of oppositely charged polyelectrolytes, sodium alginate (Alg) and poly-L-lysine (PLL), novel biodegradable microcapsules have been prepared for delivery of biological active substances (BAS). Porous spherical CaCO3 microparticles were used as templates. The template cores were coated with several layers of oppositely charged polyelectrolytes forming shell on the core surface. The core-shell microparticles were converted into hollow microcapsules by means of core dissolution with EDTA. Mild conditions for microcapsules preparation allow to perform incorporation of various biomolecules maintaining their bioactivity. Biocompatibility and biodegradability of the polyelectrolytes give a possibility to use the microcapsules as the target delivery systems. Chymotrypsin entrapped into the microcapsules was used as a model enzyme. The immobilized enzyme retained about 86% of the activity compared to a native chymotrypsin. The resultant microcapsules were stable in acidic medium and could be easily decomposed by trypsin treatment in slightly alkaline medium. Chymotrypsin was shown to be active after its release from the microcapsules decomposed by the trypsin treatment. Thus, the microcapsules prepared by the LbL technique can be used for the development of new type of BAS delivery systems in humans and animals. 相似文献
4.
Francesca Sansone Alessandra Rossi Pasquale Del Gaudio Francesco De Simone Rita Patrizia Aquino Maria Rosaria Lauro 《AAPS PharmSciTech》2009,10(2):391-401
Gastroresistant microparticles for oral administration of hesperidin (Hd) were produced by spray-drying using cellulose acetate
phthalate (CAP) as enteric polymer in different polymer/Hd weight ratio (1:1, 3:1, and 5:1), and a series of enhancers of
the dissolution rate, such as sodium carboxymethylcellulose crosslinked (CMC), sodium dodecylbenzene sulfonate (SDBS), or
Tween85. The raw materials and the microparticles were investigated by differential-scanning calorimetry, X-ray diffraction,
infrared spectroscopy and imaged using scanning electron and fluorescence microscopy. In vitro dissolution tests were conducted using a pH-change method to investigate the influence of formulative parameters on the dissolution/release
properties of the drug. CAP/Hd microparticles showed a good gastro-resistance but incomplete drug dissolution in the simulated
intestinal fluid (SIF). The presence of the enhancers in the formulation produced well-formed microparticles with different
size and morphology, containing the drug well coated by the polymer. All the enhancers were able to increase the dissolution
rate of Hd in the simulated intestinal environment without altering CAP ability to protect Hd in the acidic fluid. The spray-drying
technique and process conditions selected were effective in microencapsulating and stabilizing the flavonoid giving satisfactory
encapsulation efficiency, product yield, and microparticles morphology, and a complete drug release in the intestine. 相似文献
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目的:探讨高脂血症患者血管内皮微颗粒(EMPs)水平的表达及临床意义。方法:选取2016年5月到2017年8月期间我院收治的高脂血症患者64例,将其作为研究组。另选取同期在我院体检的健康志愿者50例作为对照组。检测两组研究对象的甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、EMPs、压力-应变弹性系数(Ep)、顺应性(AC)、硬度指数(β)、脉搏波传导速度(PWV)水平,并采用Pearson相关性分析研究组患者EMPs水平与TC、TG、LDL-C、Ep、AC、β、PWV的相关性。结果:研究组血清中TC、TG、LDL-C、EMPs水平均显著高于对照组,差异有统计学意义(P0.05);研究组的Ep、β、PWV均显著高于对照组,差异有统计学意义(P0.05),但两组AC比较无统计学差异(P0.05)。研究组患者的EMPs水平与TC、TG、LDL-C、Ep、β、PWV均呈正相关(r=0.567,0.645,0.763,0.426,0.398,0.364,P均0.05)。结论:高脂血症患者的EMPs水平明显高于健康人群,且其水平与TC、TG、LDL-C、Ep、β、PWV均呈正相关。 相似文献
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The objective of the present investigation was to reduce the bitterness with improved dissolution, in acidic medium (pH 1.2),
of mefloquine hydrochloride (MFL). Microparticles were prepared by coacervation method using Eudragit E (EE) as polymer and
sodium hydroxide as precipitant. A 32 full factorial design was used for optimization wherein the drug concentration (A) and polymer concentration (B) were selected
as independent variables and the bitterness score, particle size and dissolution at various pH were selected as the dependent
variables. The desirability function approach has been employed in order to find the best compromise between the different
experimental responses. The model is further cross validated for bias. The optimized microparticles were characterized by
FT-IR, DSC, XRPD and SEM. Bitterness score was evaluated by human gustatory sensation test. Multiple linear regression analysis
revealed that the reduced bitterness of MFL can be obtained by controlling the dissolution of microparticles at pH 6.8 and
increasing the EE concentration. The increase in polymer concentration leads to reduction in dissolution of microparticles
at pH > 5 due to its insolubility. However the dissolution studies at pH 1.2 demonstrated enhanced dissolution of MFL from
microparticles might be due to the high porosity of the microparticles, hydrophilic nature of the EE, and improved wettability,
provided by the dissolved EE. The bitterness score of microparticles was decreased to zero compared to 3+ of pure ARM. In
conclusion the bitterness of MFL was reduced with improved dissolution at acidic pH. 相似文献
9.
J. J. Parrish J. L. Susko-Parrish R. R. Handrow R. L. Ax N. L. First 《Molecular reproduction and development》1989,24(4):403-413
The effects of sulfated glycoconjugates on the preparation of mammalian sperm for fertilization were investigated. The three sulfated glycoconjugates tested were heparin, dextran sulfate, and the fucose sulfate glycoconjugate (FSG) from the sea urchin egg jelly coat. In vivo, FSG induces the acrosome reaction in sea urchin sperm. Bovine sperm were found to be capacitated by heparin and FSG as judged both by ability of lysophosphatidylcholine (LC) to induce an acrosome reaction and by ability to fertilize bovine oocytes in vitro. The mechanism by which heparin or FSG capacitated bovine sperm appeared similar, since glucose inhibited capacitation by both glycoconjugates. In contrast to effects on bovine sperm, heparin and FSG induced the acrosome reaction in capacitated hamster sperm. When hamster sperm were incubated under noncapacitating conditions, heparin had no effect on capacitation or the acrosome reaction. Three molecular weights (MW) of dextran sulfate (5,000, 8,000, 500,000) were found to capacitate bovine sperm as judged by the ability of LC to induce an acrosome reaction. Whereas bovine sperm incubated with 5,000 or 8,000 M W dextran sulfate fertilized more bovine oocytes than control sperm (P <0.05), sperm treated with 500,000 M W dextran sulfate failed to penetrate oocytes. The high-MW dextran sulfate appeared to interact with the zona pellucida and/or sperm to prevent sperm binding. Results suggest that sulfated glycoconjugates may prepare sperm for fertilization across a wide range of species. 相似文献
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冰冻人血浆37℃融化后,经钡盐吸附沉淀、硫酸铵分步盐析、DEAE-Sephadex A-50柱层析、制备性PAGE和肝素亲和层析分离,得到蛋白C。经鉴定,所得蛋白C分子量约为62kD,pI为4.69,PAGE分析高度均一,KPTT法证实其延长凝血时间,与有关文献报道相符。 相似文献
12.
Cloning, Expression and Characterization of Protein Elicitors from the Soyabean Pathogenic Fungus Phytophthora sojae 总被引:1,自引:0,他引:1
The oomycete Phytophthora sojae is a severe pathogen of soybean. Several resistance genes against races of P. sojae exist in soybean but the nature of corresponding avirulence genes is unknown. Clones encoding four different isoforms of a protein elicitor from P. sojae (sojein 1–4) belonging to the class of acidic α-elicitins have been isolated. These 98 amino acid proteins show high homology to elicitins from other Phytophthora species. The different sojein isoforms were expressed in Escherichia coli as His-tagged fusion proteins. Purified sojein as well as recombinant sojein isoforms induce hypersensitive reaction (HR)-like lesions in tobacco but are not active as race-specific elicitors in soybean. However all sojein isoforms induce defence-related genes like those encoding phenylalanine ammonia lyase, glutathione-S-transferase and chalcone synthase in tobacco and soybean plants and cell cultures. It is concluded that sojeins contribute to the induction of defence responses but that they are not involved in race specific recognition of the P. sojae races by soybean plants. 相似文献
13.
An interaction was discovered between ceruloplasmin (CP, a ferro-O2-oxidoreductase, EC 1.16.3.1), a copper-containing protein of human blood plasma, and salmon protamine (PR), a cationic polypeptide of vertebrates that provides a compact structure of spermatozoid DNA. Addition of PR to CP at a molar ratio of 2 : 1 decreases the CP electrophoretic mobility. Two types of CP binding centers for PR were determined: two centers with a high (K
d1 of 5.31 × 10−7 M) and four centers with a low affinity (K
d2 of 1.56 × 10−5 M). PR was shown to form complexes with CPs of various animal species. The CP-PR complex dissociates at an increased ionic strength (0.3 M NaCl), at pH decreased below 4.7, and/or in the presence of added polyanions (DNA, lipopolysaccharides, or heparin) or polylysine, which indicates the electrostatic nature of the interaction. The CP-PR interaction increased 1.5-fold the rate of CP-catalyzed oxidation of Fe2+. The preliminary treatment of blood plasma with arginine-Sepharose and heparin-Sepharose (to remove the blood coagulation factors) and affinity chromatography on PR-Sepharose allowed us to isolate the practically unproteolyzed monomeric CP in 90% yield; it remained stable for more than two months at 37°C.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 3, 2005, pp. 269–279.Original Russian Text Copyright © 2005 by Sokolov, Zakharova, Shavlovskii, Vasil’ev. 相似文献
14.
Korobko I. V. Korobko E. V. Chupikova N. I. Vanechkin M. A. Smirnova E. V. Kiselev S. L. Georgiev G. P. 《Molecular Biology》2002,36(3):385-388
Identification of interaction partners opens a way to direct functional characterization of proteins. Several cDNAs coding for potential partners of protein kinase MAK-V/Hunk were isolated using two-hybrid cloning in yeast. Based on the partner properties, MAK-V/Hunk was assumed to play a role in tumorigenesis and tumor progression. With the previous results of two-hybrid cloning, MAK-V/Hunk was shown to participate in vesicular transport. 相似文献
15.
The aim of this study was to reduce the photoinstability of butyl methoxydibenzoylmethane (BMDBM), the most widely used UVA
filter, by incorporating it in lipid microparticles (LMs) alone or together with the UVB filter octocrylene (OCR), acting
also as photostabilizer. Microparticles loaded with BMDBM or with combined BMDBM and OCR were produced by the hot emulsion
technique, using glyceryl behenate as lipid material and poloxamer 188 as surfactant. The LMs were characterized by release
studies, scanning electron microscopy, and powder X-ray diffractometry. The BMDBM and OCR loading was 15.2% and 10.6%, respectively.
In order to reproduce the conditions prevalent in commercial sunscreen products, the photoprotective efficacy of the LMs was
evaluated after their introduction in a model cream (oil-in-water emulsion) containing a mixture of UVA and UVB filters. A
small but statistically significant decrease in BMDBM photodegradation was obtained when the UVA filter was encapsulated alone
into the LMs (the extent of degradation was 28.6% ±2.4 for non-encapsulated BMDBM and 26.0% ±2.5 for BMDBM-loaded microparticles).
On the other hand, the co-loading of OCR in the LMs produced a more marked reduction in the light-induced decomposition of
microencapsulated BMDBM (the UVA filter loss was 21.5% ±2.2). Therefore, incorporation in lipid microparticles of BMDBM together
with the sunscreen OCR is more effective in enhancing the UVA filter photostability than LMs loaded with BMDBM alone. 相似文献
16.
Expression of the Chondroitin Sulfate Proteoglycans of Amyloid Precursor (Appican) and Amyloid Precursor-Like Protein 2 总被引:2,自引:1,他引:1
Abstract: The Alzheimer amyloid precursor (APP) protein is a member of a family of glycoproteins that includes the amyloid precursor-like proteins (APLPs). Previously, we showed that in C6 glioma cell cultures, secreted APP nexin II occurs as the core protein of a chondroitin sulfate proteoglycan (CSPG). Here, we report that among seven untransfected cell lines, expression of secreted APP CSPG was restricted to two cell lines of neural origin, namely, C6 glioma and Neuro-2a neuroblastoma (N2a) cells. Addition of dibutyryl cyclic AMP in N2a cultures, a treatment that induces the neuronal phenotype in these cells, resulted in a significant reduction in the amount of the secreted APP CSPG, although secretion of APP was only marginally affected. Growth in the presence of serum increased the size of the secreted APP CSPG, suggesting that the number and/or length of the chondroitin sulfate (CS) chains attached to the core APP varies with growth conditions. Extensive mapping with epitope-specific anti-bodies suggested that a CS chain is attached within or proximal to the Aβ sequence of APP. In contrast to the restricted expression of the APP CSPG, expression of secreted APLP2 CSPGs was observed in all cell lines examined. After chondroitinase treatment, two core proteins of ∼100 and 110 kDa were obtained that reacted with an APLP2-specific antiserum, suggesting that non-transfected cell lines contain at least two endogenous APLP2 CSPGs, probably derived by alternative splicing of the APLP2 KPI domain. The fraction of the APLP2 proteins in the CSPG form was dependent on the particular cell line examined. The proteoglycan nature of APP and APLP2 suggests that addition of the CS glycosaminoglycan chains is important for the implementation of the biological function of these proteins. However, the differential expression of these two proteoglycans suggests that their physiological roles and their possible involvement in Alzheimer's disease may differ. 相似文献
17.
Mohammadian Mehdi Salami Maryam Alavi Farhad Momen Shima Emam-Djomeh Zahra Moosavi-Movahedi Ali Akbar 《Food biophysics》2019,14(4):425-436
Food Biophysics - In this research, gum Arabic (GA) and whey protein nanofibrils (WPN) were employed for the encapsulation of curcumin as a bioactive compound with low water solubility through the... 相似文献
18.
《Molecular membrane biology》2013,30(3):219-234
Host-derived sulfated components that copurify and are physically associated with the envelope of Rauscher murine leukemia virions grown in JLS-V9 cells were characterized by digestion with chondroitinase ABC and chondroitinase AC II, as well as nitrous acid degradation. A dermatan-sulfate-chondroitin-sulfate copolymer and heparin or heparan sulfate were shown to be associated with the virions. Competitive binding studies indicated a specificity of the virions for association with heparan sulfate. The physiological importance of the association is discussed. 相似文献
19.
Nucleic acid testing requires skilled personnel and expensive instrumentation. A method for the colorimetric detection of oligonucleotides that combines cellulose microparticles with biomolecular recognition is presented. DNA sequences from Trypanosoma brucei and dengue are used as model targets. Cellulose microparticles (≈20 µm) are bioactived by anchoring anti‐biotin antibodies via fusions that combine a carbohydrate‐binding module (CBM) with the ZZ fragment of protein A. Samples are prepared by incubating DNA probes immobilized on ≈14 nm gold nanoparticles (AuNPs) with biotin‐labeled targets and mixed with bioactive microparticles. The presence of unlabeled targets could also be probed by introducing a second, biotinylated DNA probe. The target:probe‐AuNP hybrids are mixed with and captured by the microparticles, which change color from white to red. Depletion of AuNPs from the liquid is also signaled by a decrease in absorbance at 525 nm. It was possible to detect targets with concentrations as low as 50 n m . In the presence of noncomplementary targets, microparticles remain white and the liquid remains red. The system is able to discriminate targets with a high degree of homology (≈53%). Overall, it is demonstrated that simple systems for the visual detection of nucleic acids can be set up by combining cellulose microparticles with biomolecular recognition agents based on CBMs and AuNPs. 相似文献
20.
S. A. Weiss T. L. Lester S. S. Kalter R. L. Heberling 《In vitro cellular & developmental biology. Plant》1980,16(7):616-628
Summary Chemically defined media SFRE-199-1 for the growth and SFRE-199-2 for the maintenance of primary baboon kidney (Bak) cell
cultures were formulated by supplementing medium M199 with insulin, sodium pyruvate, zinc sulfate, and increasing arginine-HCl,
cysteine, cystine,l-glutamine,l-glutamic acid, glycine, histidine, tyrosine, and glucose to maximally active nontoxic concentrations. For prolonged maintenance
of the cells, physiological pH control, and blocking of excessive lactic acid accumulation in the spent medium of the cell
cultures, it was necessary to supplement the medium containing Earle's balanced salts withd-(+) galactose.
The cells grew and were maintained equally well on glass or polystyrene surfaces. Selenium, when added to growth medium or
substituted for insulin and zinc sulfate, did not stimulate cell growth. Electron microscopy showed that numerous dense particles,
approximately 250 to 400 ? in diameter, with the appearance of glycogen, were found throughout the cytoplasm in the cells
grown in SFRE-199-1 and maintained in SFRE-199-2. Echovirus types 1 to 3, poliovirus types 1 to 3, coxsackievirus types B2,
B4, B5,Herpesvirus hominis type 1, simian herpesvirusH. simiae and SA8, and simian adenovirus SV34 when titrated in primary Bak cells and grown and maintained in SFRE-199-1 and 2, respectively,
developed titers comparable to those obtained in conventionally grown and maintained cells.
This study was supported in part by National Institute of Health Grant RR00361 and World Health Organization Grant V4/181/38.
This laboratory serves as the NIH/WHO Collaborating Center for Reference and Research in Simian Viruses. 相似文献