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1.
Poly(N-isopropylacrylamide) (PIPA) with a carboxyl group at its end was coupled with amino group-carrying porous glass beads by the active-ester method. Gel permeation chromatography of dextran was carried out by using a column packed with the PIPA-carrying glass beads. The chromatograms of dextrans with various molecular weights are strongly affected by temperature: the elution time of dextran is largely changed between 25 and 32°C due to a change in the effective pore size by the transition of the PIPA chains from coils to globules on the surface of the pores of the glass beads. These results suggest the usability of PIPA-carrying glass beads as devices for thermo-controllable chromatography.  相似文献   

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《Virology》1961,15(4):473-485
The intratypic serodifferentiation technique described by Wecker has been applied to the antigenic analysis of a number of attenuated and virulent strains within the same poliovirus type. By comparison of plaque inhibition produced by strain-specific immune sera, different pools of the same attenuated strain were found to be serologically identical, whereas other attenuated and virulent viruses could be distinguished antigenically from one another. The antigenic character of viruses passed in tissue culture was relatively stable, even when other markers changed considerably. After passage through laboratory animals or in the human intestine, however, some strains were stable while others were not.The applications of this test to studies of vaccination with living attenuated polioviruses are illustrated.  相似文献   

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Proteoglycans are known to play an important role in the mineralization process, acting either as promoters or inhibitors. In this study the binding affinity of a variety of constituent glycosaminoglycan to hydroxyapatite was studied. Glycosaminoglycans (10-1000 microg ml(-1) in 0.02 M sodium acetate (pH 6.8) were constantly circulated through a hydroxyapatite column for 1 h. The total amount of glycosaminoglycan bound was determined by dimethylmethylene blue assay. The relative affinities of the different glycosaminoglycans remaining bound to hydroxyapatite was investigated by examining their release in a 0-1 M sodium phosphate gradient. Differences were noted between the desorption profiles of dermatan sulfate with two elution peaks and chondroitin 4-sulfate and chondroitin 6-sulfate each with a single peak. Dermatan sulfate and chondroitin 6-sulfate had a higher affinity for hydroxyapatite than chondroitin 4-sulfate possibly due to the presence of differing di-sulfated disaccharide ratios in the glycosaminoglycan chains. These findings suggest the presence of a variety of binding forms of each glycosaminoglycan or the differing orientation of these forms to yield different complexes with hydroxyapatite. The Ca2+ co-ordinates of the glycosaminoglycans are known to vary and may in part explain these findings.  相似文献   

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The adsorption characteristics of various proteins on beta-Ca(3)(PO(4))(2) (beta-TCP), CaHPO(4). 2H(2)O (DCPD) and CaHPO(4) (DCPA) have been investigated using liquid chromatography. Acidic proteins were eluted from these calcium phosphate surfaces by potassium phosphate buffer (KP) but not by KCl and MgCl(2), whereas basic proteins were eluted by all three eluents. Such elution behavior can be interpreted by considering two kinds of adsorbing sites on the calcium phosphates, namely positively charged sites (Ca sites) which adsorb acidic proteins, and negatively charged sites (P sites) which adsorb basic proteins. A similar behavior has also been observed on Ca(10)(PO(4))(6)(OH)(2) (HAp) and Ca(8)H(2)(PO(4))(6). 5H(2)O (OCP). The order of the ratios of Ca-to-P sites was estimated to be DCPD > OCP > HAp > DCPA > beta-TCP, which is in agreement with the order of the surface zeta potentials. In addition, the (0k0) surface of DCPD is suggested to consist mainly of Ca sites. The total number of Ca sites on beta-TCP is thought to be significantly smaller than the other calcium phosphates.  相似文献   

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The capacity of some chemically treated porous glass to adsorb tissue culture virus of tick-borne encephalitis was studied. Chemical binding of albumin and succinanhydride with the porous glass matrix was found to eliminate virion adsorption on the carrier surface. This permitted to carry out gel filtration chromatography of several virus strains and to obtain highly purified preparations of tick-borne encephalitis virus. Gel filtration on modified porous glass with different pore sizes was used for the determinations of cromatographic radius of virus particle.  相似文献   

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Staphylococcal alpha-toxin was purified from Staphylococcus aureus growth medium using adsorption chromatography on controlled pore glass beads. Elution of alpha-toxin from the unmodified glass surface of the beads with various anions generally followed the chaotropic series. Alpha-toxin, purified by glass bead chromatography, is composed of a single electrophoretic form, containing less than 2% of other forms.  相似文献   

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In order to develop bone substitutes, the design of biomaterials like calcium phosphate ceramic loaded with bone growth factor are of great interest. However, it is necessary to control the amount of growth factor adsorbed onto ceramics and the kinetics of its release. Radiolabeling of insulin-like growth factor-I (IGF-I) with 125-iodine ([(125)I]-IGF-I) and its adsorption onto porous tricalcium phosphate (TCP) cylinders enabled us to establish the time-adsorption and time-release curves using various concentrations of IGF-I. The adsorption curve increased rapidly and then flattened out at 72 h; 90% of the maximum was already reached at 24 h; and 20% of the adsorbed IGF-I was released in water within 4 days. In human serum the release was faster at 82% within 4 days. In vivo evaluation on an animal model was then performed. Rabbits' bilateral femoral cylindrical bone defects were filled with the TCP cylinders, which were either carrying IGF-I or implanted alone as a control in each rabbit. Bone turnover and ceramic resorption were stimulated by IGF-I loaded TCP according to standard radiography, dual-energy X-ray absorptiometry, histology, and histomorphometry.  相似文献   

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Summary A study of the distribution of polioviruses in Surinam was undertaken by a regular virological examination of stool specimens from children of the 1–5 year age group for a period ranging from the beginning of 1964 to the middle of 1969. All three types of poliovirus were found to circulate continuously in the child population. A correlation was found between an increased level of poliovirus circulation and the appearance of clinical poliomyelitis. The application of trivalent oral vaccine at times that a clear increase of the level of poliovirus circulation was observed, had only a partial effect on this level since the acceptance rate for the vaccine was too low.Conducted with the support of the Surinam Government and the Netherlands Foundation for the Advancement of Tropical Research (WOTRO), and with technical assistance of Miss L. Kletter and Mrs. A. Arron.on temporary detachment at the Central Public Health Laboratory, Paramaribo, Surinam.  相似文献   

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Purified preparations of haemagglutinins from Sindbis, West Nile and tick-borne encephalitis (TBE) viruses could be obtained from infected mouse brains by alkaline extraction, precipitation with protamine and chromatography on polyethylene glycol-coated controlled pore glass with 242 A pore diameter.  相似文献   

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Human fibroblast and mouse L929 cell interferons can be purified by adsoprtion to and subsequent elution from Controlled Pore Glass. Purification of 40 to 90-fold to specific activities of 1 to 5 times 10(6) units/mg of protein can be achieved in a single step, with good recovery of activity. Human leukocyte interferon does not bind to the glass and cannot be purified in this way.  相似文献   

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Dysprosium lithium-borate glass microspheres and particles, ranging from 45 to 150 microm in diameter, were reacted with a 0.25 M phosphate solution at 37 degrees C, whose pH was either 3 or 8.8. The glass reacted nonuniformly and was converted into a porous, amorphous, hydrated, dysprosium phosphate reaction product. The amorphous product had the same volume and shape (pseudomorphic) as the unreacted glass, and could be dried without cracking. After heating at 300 degrees C for 1 h, the amorphous reaction product had a specific surface area of approximately 200 m(2)/g, a pore size of approximately 30 nm, and nominal crushing strength of approximately 10 MPa. When the reaction product was heated to 600 degrees C for 15 min, the specific surface area decreased to approximately 90 m(2)/g and the nominal crushing strength increased to 35 MPa. Heating above 615 degrees C converted the amorphous dysprosium phosphate product into crystalline DyPO(4), which contained open porosity until heated above 800 degrees C for 15 min. Highly porous materials of different chemical composition can be prepared by chemically reacting a borate-based glass with an aqueous solution at low-temperature (<100 degrees C). These highly porous materials are easy to process, and are considered candidates for controlled drug delivery, catalysis, chromatographic separation, filtration, and as bioactive materials.  相似文献   

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Polioviruses, as with all RNA viruses, are in a constant process of evolution driven by different mechanisms. With multiple mechanisms for genetic variability, they are successful conformists, adapting to changes in their habitat. The evolution of polioviruses may occur with generation of point mutations followed by genetic drift and selection. The mutation rate of polioviruses based on several studies is approximately 3 × 10?2 mutations/synonymous site/year in the gene encoding viral protein 1. Genetic variation in polioviruses may also be increased by sharing of genetic data of two different poliovirus lineages by means of homologous recombination. According to the current view, recombination is considered usually to occur by strand‐switching, but a non‐replicative model has also been described. In recombination, polioviruses may either gain a set of advantageous mutations selected and fixed in previous generations of the parental viruses or get rid of deleterious ones. The prerequisites and constraints of the evolution mechanisms will be discussed. Furthermore, consequences of poliovirus evolution will be reviewed in the light of observations made on currently circulating polioviruses. We will also describe how polioviruses strike back: as wild type polioviruses approach eradication, vaccine derived strains increase their occurrence and genetic variability. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

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The results of the study of adsorption processes of recombinant HBsAg on various porous silicas are presented. The maximal yield of the recombinant antigen by absorption chromatography was observed on unmodified macroporous glass MPS-2000. A mean yield in this case was 85%. Silica C-80 modified with polyvinylpyrrolidone proved to be most acceptable for gel-penetrating chromatography. The adsorption and gel-penetrating chromatography on porous silicas proved to be an effective method for purification of recombinant HBsAg.  相似文献   

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Tissue culture rabies virus was purified by gel chromatography on chemically modified macroporous glasses (MPG). Modification of the MPG surface by egg or human albumin prevented rabies virions from interaction with the glass surface so that all purified virus was eluted from the column. Chemically modified MPG could be used on a preparative scale for the purification of both infectious and inactivated rabies virus, the immunogenicity of the latter having been preserved. Protein content of the purified virus fractions was up to 4 microgram/ml, of which virus protein represented up to 5%.  相似文献   

19.
E Floor  O Grad  S E Leeman 《Neuroscience》1982,7(7):1647-1655
Subsynaptosomal particles containing the peptide, substance P, detected by radioimmunoassay were prepared by osmotic lysis of rat brainstem synaptosomes and chromatographed on a calibrated column of controlled pore glass beads of nominal pore size 300 nm. Immunoreactive substance P migrated on this column with particles of apparent mean diameter 117 nm. This particulate, immunoreactive substance P was indistinguishable from synthetic substance P by gel filtration and reverse-phase high pressure liquid chromatography. The specific activity of substance P with respect to protein in peak fractions was 140 pmoles/mg protein, 75-fold higher than in the crude homogenate. Particulate substance P was resistant to attack by endogenous proteases in a crude preparation. Depolarization of synaptosomes with 75 muM veratridine prior to vesicle purification decreased the recovery of particulate substance P 37%. This depletion was dependent on external calcium ions and was blocked by 1 muM tetrodotoxin. The foregoing properties of particulate substance P are consistent with its identification with the large, intraterminal substance P-positive vesicles seen by immunocytochemistry and suggest that these vesicles are involved in the release of substance P.  相似文献   

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Summary Mengovirus, extracted from infected L-cell cultures with Freon 113 and concentrated from the acqueous phase with polyethyleneglycol, was chromatographed on protein-coated controlled pore glass (CPG). The covalent binding of protein to CPG is described. Further purification and concentration of mengovirus was achieved by isopycnic density gradient centrifugation in solutions of either CsCl or salts of iodinated benzoic acid derivatives. The described procedure is superior to conventional methods for the isolation and purification of large quantities of mengovirus. It yields highly purified virus preparations within a short time and a recovery of more than 50 per cent of the starting infectivity.With 2 Figures  相似文献   

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