101
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Silva F, Lourenço O, Queiroz JA, Domingues FC. Bacteriostatic versus bactericidal activity of ciprofloxacin in Escherichia coli assessed by flow cytometry using a novel far-red dye. J Antibiot (Tokyo) 2011; 64:321-5. [DOI: 10.1038/ja.2011.5] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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102
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Gaspar VM, Sousa F, Queiroz JA, Correia IJ. Formulation of chitosan-TPP-pDNA nanocapsules for gene therapy applications. NANOTECHNOLOGY 2011; 22:015101. [PMID: 21135452 DOI: 10.1088/0957-4484/22/1/015101] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The encapsulation of DNA inside nanoparticles meant for gene delivery applications is a challenging process where several parameters need to be modulated in order to design nanocapsules with specific tailored characteristics. The purpose of this study was to investigate and improve the formulation parameters of plasmid DNA (pDNA) loaded in chitosan nanocapsules using tripolyphosphate (TPP) as polyanionic crosslinker. Nanocapsule morphology and encapsulation efficiency were analyzed as a function of chitosan degree of deacetylation and chitosan-TPP ratio. The manipulation of these parameters influenced not only the particle size but also the encapsulation and release of pDNA. Consequently the transfection efficiency of the nanoparticulated systems was also enhanced with the optimization of the particle characteristics. Overall, the differently formulated nanoparticulated systems possess singular properties that can be employed according to the desired gene delivery application.
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103
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Raposo R, Barroso M, Fonseca S, Costa S, Queiroz JA, Gallardo E, Dias M. Determination of eight selected organophosphorus insecticides in postmortem blood samples using solid-phase extraction and gas chromatography/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:3187-3194. [PMID: 20941767 DOI: 10.1002/rcm.4765] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A simple, rapid and sensitive method is described for the determination of omethoate, dimethoate, diazinon, chlorpyrifos, parathion-ethyl, chlorfenvinphos, quinalphos and azinphos-ethyl in postmortem whole blood samples. The analytes and internal standard (ethion) were isolated from the matrix by solid-phase extraction, and were analysed by gas chromatography/mass spectrometry in the selected ion monitoring mode. The method has shown to be selective after analysis of postmortem samples of 40 different origins. Calibration curves were established between 0.05 (0.1 for omethoate) and 25 µg/mL, and the values obtained for intra- and interday precision and accuracy were within the criteria usually accepted for bioanalytical method validation. Lower limits of quantitation were 50 ng/mL for all compounds, except for omethoate (100 ng/mL); the limits of identification of the method were 25 ng/mL for all analytes, except for omethoate, for which 50 ng/mL was obtained. Absolute recovery was determined at three concentration levels, and ranged from 31 to 108%. The proposed method is simple and fast, and can be routinely applied in the determination of these compounds in postmortem whole blood samples within the scope of forensic toxicology. In addition, mass spectrometry has demonstrated to be a powerful and indispensable tool for the unequivocal identification of the analytes, since the acceptance criteria were accomplished even at very low levels, thus allowing obtaining forensically valid and sound results.
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104
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Ferreira S, Gil N, Queiroz JA, Duarte AP, Domingues FC. Bioethanol from the Portuguese forest residue Pterospartum tridentatum--an evaluation of pretreatment strategy for enzymatic saccharification and sugars fermentation. BIORESOURCE TECHNOLOGY 2010; 101:7797-7803. [PMID: 20965126 DOI: 10.1016/j.biortech.2010.05.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 05/10/2010] [Accepted: 05/17/2010] [Indexed: 05/30/2023]
Abstract
Under the current energy scenario, the development of alternatives to fossil fuels, like bioethanol from lignocellulosic materials, is highly relevant. Therefore it is important to search and study new raw materials and to optimize the different steps that lead to bioethanol production. In this work, acid diluted pretreatment was optimized considering the release of sugars. Under the optimal conditions, the reducing sugars yield was of 293.4mg/g of dry biomass in liquid fraction. The tested pretreated samples of Pterospartum tridentatum that presented a higher glucose yield in enzymatic saccharification where those that were subject to a pretreatment at 180°C for 75min with 2.75% (w/w) of sulfuric acid when using a biomass/liquid ratio of 2.25g/10mL leading to a maximum yield of glucose that was 92% of the theoretical maximum. From the fermentation of filtrates it was possible to obtain a maximum ethanol yield of 0.26g ethanol/g total sugars, without previous detoxification.
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105
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Sousa A, Sousa F, Queiroz JA. Differential interactions of plasmid DNA, RNA and genomic DNA with amino acid-based affinity matrices. J Sep Sci 2010; 33:2610-8. [DOI: 10.1002/jssc.201000347] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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106
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Silva A, Boto REF, Tomaz CT, Queiroz JA, Almeida P. Rhodamine B as ligand for affinity chromatography: chromatographic studies on derivatized beaded cellulose. J Chromatogr Sci 2010; 48:240-4. [PMID: 20223093 DOI: 10.1093/chromsci/48.3.240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Rhodamine B (RB) post-grafted onto beaded cellulose by a curing method is used as a biomimetic ligand in dye affinity chromatography. The grafted materials obtained are qualitatively characterized by scanning electron microscope and fourier transformed infrared spectroscopy. An amount of 76.79 mmol RB/g dyed cellulose is determined by elemental analysis. The RB affinity interaction with the trypsin, alpha-chymotrypsin, and BSA (bovine serum albumin) is analyzed using different mobile phase composition. The results show a selective separation of a mixture of BSA and trypsin into two single peaks by step elution with 1.75 M, 0.5 M, and 0 M ammonium sulphate in the eluent buffer. A good reproducibility of the retention time is obtained for these proteins in the mixture with typical values of 8.0 +/- 0.2 min for BSA and 20.0 +/- 0.2 min for trypsin, showing a possible application in the purification of samples with different composition.
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107
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Silva F, Passarinha L, Sousa F, Queiroz JA, Domingues FC. Influence of growth conditions on plasmid DNA production. J Microbiol Biotechnol 2010; 19:1408-14. [PMID: 19996695 DOI: 10.4014/jmb.0805.329] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The obtention of high yields of purified plasmid DNA is viewed as an essential issue to be considered towards efficient production of DNA vaccines and therapeutic plasmids. In this work, Escherichia coli DH5alpha bearing the pVAX1-LacZ plasmid was grown in a developed semi-defined medium at different temperatures and tryptone concentrations. Analysis of pDNA yields and E. coli morphology revealed that at higher temperatures (37 and 40 degrees C), higher specific yields and E. coli filamentation were obtained. However, the best results were achieved when a lower tryptone concentration was used. This approach was shown to be a powerful tool to promote plasmid amplification, keeping the desirable plasmid structure, and favoring the attainment of quality. Our results suggest that by using tryptone alone as an amino acid source, pDNA amplification was improved and a specific yield of 20.43 mg pDNA/g dcw was achieved, proving that this strategy can improve pDNA yield even at a small scale.
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108
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Silva F, Lourenço O, Pina-Vaz C, Rodrigues AG, Queiroz JA, Domingues FC. The use of DRAQ5 to monitor intracellular DNA in Escherichia coli by flow cytometry. J Fluoresc 2010; 20:907-14. [PMID: 20352307 DOI: 10.1007/s10895-010-0636-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 03/15/2010] [Indexed: 10/19/2022]
Abstract
Flow cytometry provides a rapid and high-content multiparameter analysis of individual microorganisms within a population. In the past years, several fluorescent stains were developed in order to monitor DNA content distribution and cell-cycle phases, mainly in eukaryotic cells. Recently, due to its low detection limits, several of these fluorescent stains were also applied to prokaryotic cells. In this study, the ability of a novel far-red fluorescent stain DRAQ5 in assessing intracellular DNA content distribution in Escherichia coli DH5alpha was evaluated. The results showed that a DRAQ5-labelled live E. coli suspension can be obtained by incubation of 1 x 10(6) cells/mL with 5 microM DRAQ5 in PBS buffer supplemented with EDTA (pH = 7.4) during 30 min at 37 degrees C. Flow cytometric analysis of fixed E. coli cells revealed that ethanol should be used in detriment of glutaraldehyde for DRAQ5 labelling. After the analysis of RNase and DNase digested samples, DRAQ5 was proven to be a specific DNA labelling stain. The present study demonstrates that the use of DRAQ5 as a DNA-labelling stain provides an easy assessment of intracellular DNA content and cell-cycle phases in gram-negative bacteria such as E. coli.
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109
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Sousa F, Passarinha L, Queiroz JA. Biomedical application of plasmid DNA in gene therapy: a new challenge for chromatography. Biotechnol Genet Eng Rev 2010; 26:83-116. [PMID: 21415877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Gene therapy and DNA vaccination are clinical fields gradually emerging in the last few decades, in particular after the discovery of some gene-related diseases. The increased relevance of biomedical applications of plasmid DNA (pDNA) to induce therapeutic effects has had a great impact on biopharmaceutical research and industry. Although there are several steps involved in the pDNA manufacturing process, the several unit operations must be designed and integrated into a global process. After the plasmid has been designed according to the requirements for clinical administeration to humans, it is biosynthesised mainly by an E. coli host. The overriding priority of the production process is to improve plasmid quantity - the production conditions need to be optimised to guarantee pDNA stability and biological activity. The complexity and diversity of biomolecules present on the pDNA-containing extracts represent the main concern and limitation to achieve pure and biologically active pDNA. There has been a recent intenstification of the improvement of existing purification procedures or the establishment of novel schemes for plasmid purification. This review focuses on the progress and relevance of chromatographic methodologies in the purification of pDNA-based therapeutic products. The review will attempt to assemble their different contributions of the different chromatographic procedures that are being used in the pDNA purification area. The advantages and disadvantages of the different chromatographic techniques, as well as the most significant improvements in response to the challenge of purifying pDNA will be discussed, emphasizing the future directions in this field.
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110
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Sousa A, Sousa F, Prazeres DMF, Queiroz JA. Histidine affinity chromatography of homo-oligonucleotides. Role of multiple interactions on retention. Biomed Chromatogr 2009; 23:745-53. [PMID: 19296518 DOI: 10.1002/bmc.1179] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The recent application of histidine-agarose affinity supports in plasmid purification takes advantage of the biorecognition of nucleic acid bases by the histidine ligand. This consideration prompted the need for better understanding the interactions involved in affinity chromatography of plasmid DNA with the histidine-agarose support. In this work, we used synthetic homo-deoxyoligonucleotides with different sizes (1-30 nucleotides long), to explore the effect of several conditions like hydrophobic character of the individual bases, presence of secondary structures, temperature, pH and salt concentration on the mechanism of retention of nucleic acids to histidine-agarose support. One of the most striking results shows that histidine interacts preferentially with guanine, and the presence of secondary structures on polyA and polyG oligonucleotides has a significant influence on retention. Otherwise, the temperature manipulation has not shown a direct influence on oligonucleotide retention, only inducing conformational changes on secondary structures. Overall, the results obtained provide valuable information for the future development and implementation of histidine and other amino acids as ligands in chromatography for the purification of plasmid DNA and other nucleic acids, by improving the knowledge of the interactions involved as well as of the parameters influencing the retention.
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111
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Passrinha LA, Bonifacio MJ, Queiroz JA. Application of a fed-batch bioprocess for the heterologous production of hSCOMT in Escherichia coli. J Microbiol Biotechnol 2009; 19:972-981. [PMID: 19809255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this paper, a fed-batch cultivation process in recombinant Escherichia coli BL21(DE3) bacteria, for the production of human soluble catechol-O-methyltransferase (hSCOMT), is presented. For the first time, a straightforward model is applied in a recombinant hSCOMT expression system and distinguishes an initial cell growth phase from a protein production phase upon induction. Specifically, the kinetic model predicts biomass, substrate, and product concentrations in the culture over time and was identified from a series of fed-batch experiments designed by testing several feed profiles. The main advantage of this model is that its parameters can be identified more reliably from distinct fed-batch strategies, such as glycerol pulses and exponential followed by constant substrate additions. Interestingly, with the limited amount of data available, the proposed model accomplishes satisfactorily the experimental results obtained for the three state variables, and no exhaustive process knowledge is required. The comparison of the measurement data obtained in a validation experiment with the model predictions showed the great extrapolation capability of the model presented, which could provide new complementary information for the COMT production system.
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112
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Sousa A, Sousa F, Queiroz JA. Selectivity of arginine chromatography in promoting different interactions using synthetic oligonucleotides as model. J Sep Sci 2009; 32:1665-72. [PMID: 19370734 DOI: 10.1002/jssc.200800690] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Arginine has been effectively used in several chromatography methodologies to improve recovery, resolution, and to suppress aggregation. Recently, arginine chromatography was used to fully separate supercoiled and open circular plasmid DNA isoforms. The specific recognition of supercoiled plasmid isoform by arginine was hypothesised to be due to the ability of arginine matrix to be involved in complex interactions that are partly dependent on the conformation of the DNA molecule. In light of these considerations a study was conducted to understand the several interactions that a DNA molecule can promote with the arginine support, in accordance with the chromatographic conditions established. Consequently, knowing the ideal conditions to promote the specific interactions, it could be possible to perform a more targeted and efficient purification. This work describes the chromatography of oligonucleotides with sizes up to 30 bases on the arginine-agarose gel. The effect of several conditions like hydrophobic character of the individual bases, molecular mass of the oligonucleotides, presence of secondary structures, temperature and elution buffer composition (salt and arginine supplemented buffer) was investigated. According to previous atomic data referent to possible interactions between amino acids and DNA nucleotides, arginine can preferentially interact with guanine by hydrogen bond, but other interactions (ionic interactions, van der Waals contacts, water mediated bonds) may also be present and become dominant depending on the conditions used. The results also revealed that the application of arginine in the elution buffer led to an effective elution of oligonucleotides from the arginine chromatographic support by a competition strategy. In general, it was suggested that the affinity interaction promoted by the arginine support is responsible for the specific recognition of particular oligonucleotide bases, involving multiple interactions.
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113
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Ferreira S, Duarte AP, Ribeiro MH, Queiroz JA, Domingues FC. Response surface optimization of enzymatic hydrolysis of Cistus ladanifer and Cytisus striatus for bioethanol production. Biochem Eng J 2009. [DOI: 10.1016/j.bej.2009.03.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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114
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Morão A, Nunes JC, Sousa F, Amorim MTPD, Escobar IC, Queiroz JA. Development of a model for membrane filtration of long and flexible macromolecules: Application to predict dextran and linear DNA rejections in ultrafiltration. J Memb Sci 2009. [DOI: 10.1016/j.memsci.2009.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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115
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Sousa F, Prazeres DMF, Queiroz JA. Improvement of transfection efficiency by using supercoiled plasmid DNA purified with arginine affinity chromatography. J Gene Med 2009; 11:79-88. [DOI: 10.1002/jgm.1272] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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116
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Nunes VS, Bonifácio MJ, Queiroz JA, Passarinha LA. Assessment of COMT isolation by HIC using a dual salt system and low temperature. Biomed Chromatogr 2009; 24:858-62. [PMID: 20024892 DOI: 10.1002/bmc.1377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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117
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Barroso M, Dias M, Vieira DN, Queiroz JA, López-Rivadulla M. Development and validation of an analytical method for the simultaneous determination of cocaine and its main metabolite, benzoylecgonine, in human hair by gas chromatography/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:3320-3326. [PMID: 18819113 DOI: 10.1002/rcm.3738] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new, simple and rapid procedure has been developed and validated for the determination of cocaine and its main metabolite, benzoylecgonine, in human hair samples. After extraction from within the hair matrix by a mixture of methanol/hydrochloric acid (2:1) at 65 degrees C for 3 h, and sample cleanup by mixed-mode solid-phase extraction (SPE), the extracts were analyzed by gas chromatography/mass spectrometry (GC/MS), after derivatization with N-methyl-N-(trimethylsilyl)trifluoroacetamide with 5% chlorotrimethylsilane. Using a sample size of only 20 mg of hair, limits of detection (LODs) and quantitation (LOQs) were, respectively, 20 and 50 pg/mg for cocaine, and 15 and 50 pg/mg for benzoylecgonine, achieving the cut-off values proposed by the Society of Hair Testing for the analysis of these compounds in hair. The method was found to be linear (weighing factor of 1/x) between the LOQ and 20 ng/mg for both compounds, with correlation coefficients ranging from 0.9974 to 0.9996 for cocaine; and from 0.9981 to 0.9994 for benzoylecgonine. Intra- and interday precision and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The sample cleanup step presented a mean absolute recovery greater than 90% for both compounds. The developed method may be useful in forensic toxicology laboratories for the analysis of cocaine and benzoylecgonine in hair samples, taking into account its speed (only 3 h are required for the extraction of the analytes from within the matrix, whereas 5 h or even overnight extractions have been reported) and the low limits achieved (using a single quadrupole mass spectrometer, which is available in most laboratories).
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118
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Gouveia IC, Fiadeiro JM, Queiroz JA. Enzymatic removal of plant residues from wool: Application of experimental design techniques for optimization parameters. Biochem Eng J 2008. [DOI: 10.1016/j.bej.2008.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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119
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Sousa F, Prazeres DM, Queiroz JA. Affinity chromatography approaches to overcome the challenges of purifying plasmid DNA. Trends Biotechnol 2008; 26:518-25. [DOI: 10.1016/j.tibtech.2008.05.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 05/21/2008] [Accepted: 05/28/2008] [Indexed: 02/05/2023]
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120
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Passarinha LA, Bonifácio MJ, Soares-da-Silva P, Queiroz JA. A new approach on the purification of recombinant human soluble catechol-O-methyltransferase from an Escherichia coli extract using hydrophobic interaction chromatography. J Chromatogr A 2008; 1177:287-96. [PMID: 17588591 DOI: 10.1016/j.chroma.2007.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 05/29/2007] [Accepted: 06/01/2007] [Indexed: 11/30/2022]
Abstract
Catechol-O-methyltransferase (COMT) is a significant target in protein engineering due to its role not only in normal brain function but also to its possible involvement in some human disorders. In this work, a new approach was employed for the purification of recombinant human soluble COMT (hSCOMT) using hydrophobic interaction chromatography, as the main isolation method, from an Escherichia coli culture broth. A simplified overall process flow is proposed. Indeed, with an optimized heterologous expression system for recombinant hSCOMT production, such as E. coli, it was possible to produce and recover the active monomeric enzyme directly from the cell crude culture broth either by a freeze/thaw or ultrasonication lysis step. The recombinant enzyme present in the bacterial soluble fraction, exhibited similar affinity for epinephrine (K(m) 276 [215; 337] microM) and the methyl donor (S-adenosyl-L-methionine, SAMe) (K(m) 36 [30; 41]microM) as human SCOMT. After the precipitation step by 55% of ammonium sulphate, a HIC step on the butyl-sepharose resin was found to be highly effective in selectively eluting a range of contaminating key proteins present in the concentrate soluble extract. Consequently, the partially purified eluate from HIC could then be loaded and polished by gel filtration in order to increase the process efficiency. The final product appeared as a single band in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The procedure resulted in a global 10.9-fold purification with a specific activity of 5500 nmol/h/mg of protein. The widespread applicability of the process, here described, to different COMT sources could make this protocol highly useful for all studies requiring purified and active COMT proteins.
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121
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Tomaz CT, Rocha AS, Queiroz JA. Hydrophobic interaction chromatography ofTrichoderma reeseicellulases on polypropylene glycol–sepharose. SEP SCI TECHNOL 2007. [DOI: 10.1081/ss-120002741] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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122
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Sousa F, Prazeres DMF, Queiroz JA. Dynamic binding capacity of plasmid DNA in histidine–agarose chromatography. Biomed Chromatogr 2007; 21:993-8. [PMID: 17472220 DOI: 10.1002/bmc.846] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The use of histidine-agarose chromatography in the purification of supercoiled (sc) plasmid DNA (pDNA) from Escherichia coli lysates has been reported recently. In the current work we describe a set of breakthrough experiments which were designed to study the effect of parameters such as flow-rate, temperature, concentration and conformation on the dynamic binding capacity of pDNA to the histidine support. One of the most striking results shows that the dynamic binding capacity for sc pDNA decreases linearly from 250.8 to 192.0 microg sc pDNA/mL when the temperature is varied from 5 to 24 degrees C. This behaviour was attributed to temperature-induced, pre-denaturation conformational changes which promote the removal of negative superhelical turns in sc pDNA molecules and decrease the interaction of DNA bases with the histidine ligands. The capacity for sc pDNA was highly improved when using feeds with higher pDNA concentrations, a phenomenon which was attributed to the fact that pDNA molecules in more concentrated solutions are significantly compressed. A maximum capacity of 530.0 microg pDNA/mL gel was obtained when using a 125 microg/mL pDNA feed at 1 mL/min and 5 degrees C, a figure which is comparable to the plasmid capacity values published for other chromatographic supports. Finally, a more than 2-fold increase in capacity was obtained when changing from open circular to sc pDNA solutions. Overall, the results obtained provide valuable information for the future development and implementation of histidine chromatography in the process scale purification of pDNA.
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123
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Passarinha LA, Bonifácio MJ, Queiroz JA. Comparative study on the interaction of recombinant human soluble catechol-O-methyltransferase on some hydrophobic adsorbents. Biomed Chromatogr 2007; 21:430-8. [PMID: 17294500 DOI: 10.1002/bmc.779] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The main scope of this work is the evaluation and potential application of hydrophobic interaction chromatography in the isolation of recombinant human soluble catechol-O-methyltransferase (hSCOMT) from an Escherichia coli cell extract. Therefore, a comparative study on the interaction of recombinant hSCOMT with different hydrophobic adsorbents (butyl-, octyl-, phenyl- and epoxy-Sepharose), was developed. The four adsorbents were evaluated in terms of selectivity, recovery and fractionation of recombinant hSCOMT from its Escherichia coli-free culture broth. Our data shows that the adjustment of the ionic strength on the mobile phase and the type of hydrophobic ligand are the most useful factors for a complete binding of hSCOMT and a selective fractionation of contaminating proteins. The results of these studies demonstrate that, although epoxy-Sepharose is used as a last resort due to the high salt concentrations needed, hSCOMT bind to the other three resins at low concentrations of ammonium sulfate (< or = 0.6 M) and eluted just by decreasing the ionic strength on the eluent to 0 M, without loss of specific of activity. The stepwise gradient with 0.6, 0.2, 0.075 and 0 M of ammonium sulfate onto a butyl-Sepharose media was found to be the most effective in the isolation of hSCOMT, leading to an enzyme solution with a 3.9-fold increased in specific activity. Since biochemical and structural studies require significant quantities of the enzyme in an active form, the above described approach may give some insight into the optimization and development of new purification strategies of mammalian COMTs.
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124
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Passarinha LA, Bonifácio MJ, Queiroz JA. The effect of temperature on the analysis of metanephrine for catechol-O-methyltransferase activity assay by HPLC with electrochemical detection. Biomed Chromatogr 2006; 20:937-44. [PMID: 16470514 DOI: 10.1002/bmc.623] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The enzyme catechol-O-methyltransferase (COMT) plays an important role in the metabolism of catechol estrogens and degradation of the catecholamine neurotransmitters, such as epinephrine. Several analytical methods, mainly high-performance liquid chromatography with electrochemical amperometric detection, have been reported for the analysis of catecholamines and their metabolites in biological fluids. In this paper we report the relevance of controlling temperature in calibration procedures of metanephrine, an O-methylated product of catechol-O-methyltransferase, using epinephrine as substrate. The results at higher temperatures show shorter retention times of metanephrine, no undue band-broadening and increased electro signals. This study also showed that, despite different temperatures leading to similarly specific activities of recombinant human COMT as expected, there are additional advantages in flow analytical methods where good sensitivity, efficiency and selectivity is required, mainly in tissues with low levels of COMT activity.
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125
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Sousa F, Melo A, Almeida S, Paixão P, Queiroz JA, Domingues FC. Isolation of a fusion protein containing the antigenic domain 1 of human cytomegalovirus glycoprotein B and its application in ELISA tests. Biotechnol Lett 2005; 28:73-7. [PMID: 16369688 DOI: 10.1007/s10529-005-4949-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/26/2005] [Accepted: 10/31/2005] [Indexed: 10/25/2022]
Abstract
The glycoprotein B (gB) of human cytomegalovirus represents a dominant antigen for the humoral immune response. The immunodominant region on gB is the antigenic domain 1 (AD-1), a complex structure that requires a minimal continuous sequence of more than 75 amino acids for antibody binding. In this study, this domain was expressed in Escherichia coli as a fusion protein with beta-galactosidase but yielded insoluble protein aggregates as inclusion bodies. To recover the fusion protein, inclusion bodies were solubilized by two extractions with urea 8 M: and the fusion protein then isolated using gel filtration chromatography. After confirmation of fusion protein antigenicity by Western blotting, the purified product was used as the capturing antigen in an enzyme-linked immunosorbent assay (ELISA) to determine the presence of viral antibodies in serum samples of pregnant women. A cut-off point of approximately 0.2 absorbance units could discriminate the results of seropositive from seronegative pregnant women. The data indicates the potential usefulness of the fusion protein for the development of immunoassay for detection of the HCMV antibodies.
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126
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Ferreira S, Sousa F, Queiroz JA, Domingues FC. Improved Recovery of a Fusion Protein Containing the Antigenic Domain 1 of the Human Cytomegalovirus Glycoprotein B. Biotechnol Lett 2005; 27:1241-5. [PMID: 16158270 DOI: 10.1007/s10529-005-0024-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 06/13/2005] [Accepted: 06/13/2005] [Indexed: 10/25/2022]
Abstract
Heterologous expression in Escherichia coli often leads to production of the expressed proteins as insoluble and inactive inclusion bodies. The general strategy for protein recovery includes isolation and washing of inclusion bodies, solubilization of aggregated protein and refolding of solubilized protein. The process of refolding, as well as the other steps involved in inclusion body recovery, must be optimized according to the characteristics of each protein. For the development of reliable and inexpensive serodiagnostic tests, the antigenic domain 1 (AD-1) of human cytomegalovirus glycoprotein B was expressed in E. coli and a process was developed to increase recovery of the fusion protein containing AD-1. A comparison of disruption methods and different conditions involved in recovery of this fusion protein from inclusion bodies is presented. The developed method gives a high yield of the fusion protein with a purity sufficient for use in diagnostic tests.
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127
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Sousa F, Tomaz CT, Prazeres DMF, Queiroz JA. Separation of supercoiled and open circular plasmid DNA isoforms by chromatography with a histidine–agarose support. Anal Biochem 2005; 343:183-5. [PMID: 16018873 DOI: 10.1016/j.ab.2005.03.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 03/03/2005] [Accepted: 03/07/2005] [Indexed: 11/29/2022]
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128
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Abstract
Liquid chromatography plays a central role in process-scale manufacturing of therapeutic plasmid DNA (pDNA) for gene therapy and DNA vaccination. Apart from its use as a preparative purification step, it is also very useful as an analytical tool to monitor and control pDNA quality during processing and in final formulations. This paper gives an overview of the use of pDNA chromatography. The specificity of pDNA purification and the consequent limitations to the performance of chromatography are described. Strategies currently used to overcome those limitations, as well as other possible solutions are presented. Applications of the different types of chromatography to the purification of therapeutic pDNA are reviewed, and the main advantages and disadvantages behind each technique highlighted.
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129
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Dias-Cabral AC, Ferreira AS, Phillips J, Queiroz JA, Pinto NG. The effects of ligand chain length, salt concentration and temperature on the adsorption of bovine serum albumin onto polypropyleneglycol-Sepharose. Biomed Chromatogr 2005; 19:606-16. [PMID: 15803451 DOI: 10.1002/bmc.487] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The interaction thermodynamics associated with bovine serum albumin adsorption on polypropylene glycol (n=3)-Sepharose CL-6B and polypropylene glycol (n=7)-Sepharose CL-6B, using ammonium sulfate as the modulator was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model, preferential interaction approach and van't Hoff plots applied to HIC systems. Preferential interaction analysis indicated a strong entropic driving force under linear conditions, due to the release of a large amount of solvent on adsorption. In contrast, flow microcalorimetry under overloaded conditions showed that the adsorption of bovine serum albumin may be entropically or enthalpically driven. It is postulated that adsorption in the nonlinear region is influenced by the degree of water release, protein-protein interactions on the surface, reorientation of ligand, and conformational changes in the protein.
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130
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Tomaz CT, Queiroz JA. Fractionation of Trichoderma Reesei Cellulases by Hydrophobic Interaction Chromatography on Phenyl-Sepharose. Biotechnol Lett 2004; 26:223-7. [PMID: 15049367 DOI: 10.1023/b:bile.0000013719.92024.04] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Trichoderma reesei cellulase complex was fractionated using hydrophobic interaction chromatography with a phenyl-Sepharose column. Using a linear gradient of ammonium sulphate in the eluent buffer, a selective separation of endoglucanases was obtained at 15 degrees C with a four-fold increase in specific activity.
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131
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Dias-Cabral AC, Queiroz JA, Pinto NG. Effect of salts and temperature on the adsorption of bovine serum albumin on polypropylene glycol-Sepharose under linear and overloaded chromatographic conditions. J Chromatogr A 2003; 1018:137-53. [PMID: 14620566 DOI: 10.1016/j.chroma.2003.07.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interaction thermodynamics associated with bovine serum albumin (BSA) adsorption on polypropylene glycol (PPG)-Sepharose CL-6B gel, using ammonium and sodium sulfate was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model and preferential interaction approach. Preferential interaction analysis indicated a strong entropic driving force due to the release of a large amount of solvent on adsorption. Flow microcalorimetry provided direct heat of adsorption measurements under overloaded conditions and confirmed that the adsorption of BSA on PPG-Sepharose was entropically driven within the range of conditions studied. Using these data in combination with isotherm measurements, it is shown that protein surface coverage, salt concentration, salt type and temperature affect the enthalpic and entropic behavior in hydrophobic interaction chromatography (HIC). This study shows that protein-sorbent interactions can be strongly influenced by the degree of water release, protein-protein interactions on the surface, and the re-orientation and/or reconfiguration of the adsorbed protein.
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132
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Diogo MM, Prazeres DMF, Pinto NG, Queiroz JA. Hydrophobic interaction chromatography of homo-oligonucleotides on derivatized sepharose CL-6B. Using and relating two different models for describing the effect of salt and temperature on retention. J Chromatogr A 2003; 1006:137-48. [PMID: 12938882 DOI: 10.1016/s0021-9673(03)00918-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effect of salt and temperature on the interaction of homo-oligonucleotides with a derivatized Sepharose CL-6B hydrophobic support has been explained by the application of two different models: the solvophobic theory and the preferential interaction analysis. It has been shown that the two approaches give adequate descriptions of the experimental results. The models were used in order to estimate, respectively the parameter C, which is proportional to the reduction in hydrophobic exposed surface area upon adsorption, and the number of water and salt ions released upon adsorption. It was concluded that the magnitude of these parameters can be strongly influenced by the temperature, the hydrophobicity of the bases of the nucleotides, the molecular mass of the oligonucleotides and the presence of secondary structures. Parameter C was quantitatively related with the number of water molecules and salt ions released upon adsorption. These parameters were found to correlate linearly in cases where structural changes with temperature are not significant.
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133
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Diogo MM, Queiroz JA, Prazeres DMF. Assessment of purity and quantification of plasmid DNA in process solutions using high-performance hydrophobic interaction chromatography. J Chromatogr A 2003; 998:109-17. [PMID: 12862377 DOI: 10.1016/s0021-9673(03)00618-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A hydrophobic interaction HPLC method was developed for the quantification of plasmid DNA and assessment of its purity in crude Escherichia coli lysates and other process streams. A Phenyl Sepharose Source (Amersham Biosciences) column was used to separate the double-stranded plasmid DNA molecules from the more hydrophobic impurities present in the process streams. The method is rapid (each analysis takes 7 min), reproducible, easy to perform and does not require previous digestion of RNA in samples with RNase or other pre-treatment. Furthermore, it is capable of handling heavily contaminated samples, with less than 5% of plasmid DNA thus constituting a good alternative to other less robust analytical techniques currently in use.
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134
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Diogo MM, Queiroz JA, Prazeres DM. Studies on the retention of plasmid DNA and Escherichia coli nucleic acids by hydrophobic interaction chromatography. BIOSEPARATION 2002; 10:211-20. [PMID: 12233744 DOI: 10.1023/a:1016361721316] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work presents studies on the interactions of supercoiled plasmid DNA and Escherichia coli genomic DNA (gDNA) and RNA, with an hydrophobic interaction chromatography (HIC) gel, obtained by derivatisation of Sepharose CL-6B with 1,4-butanediol diglycidyl ether. Nucleic acids purified from E. coli were injected separately in the above HIC column and eluted with 1.5 M (NH4)2SO4 in the buffer. The column was able to separate single-stranded from double-stranded nucleic acids. RNA and denatured gDNA were retarded in a different way due to the interactions of the exposed hydrophobic bases with the ligands. Supercoiled plasmid DNA, on the contrary, eluted in the flowthrough.
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135
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Diogo MM, Queiroz JA, Prazeres DMF. Hydrophobic interaction chromatography of homo-oligonucleotides on derivatized Sepharose CL-6B. Application of the solvophobic theory. J Chromatogr A 2002; 944:119-28. [PMID: 11833544 DOI: 10.1016/s0021-9673(01)01388-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This work describes the hydrophobic interaction chromatography of homo-deoxyoligonucleotides polyA, polyT and polyU with sizes up to 30 bases on a Sepharose gel derivatized with the 1,4-butanediol diglycidyl ether. The oligonucleotides interacted differently with the column according to the molecular mass, the hydrophobic character of the individual bases, the secondary structure of the molecule and the concentration of ammonium sulphate in the eluent. The retention factor, k', was determined from the chromatographic profiles at different concentrations of ammonium sulphate. A linear relationship between log k' and the concentration of ammonium sulphate in the eluent was found for all oligonucleotides at the higher concentrations (> 1.0 M) of ammonium sulphate. The slope of these plots, termed the hydrophobic interaction parameter, was found to be an increasing function of the number of nucleotides. The same plots reveal that polyA molecules with high molecular mass have lower retention factors when compared with polyT, an observation that was not expected since the hydrophobicity of adenine is higher than that of thymine. This behaviour was due to the existence of secondary structures in polyA, which decrease the exposed hydrophobic area of the molecule.
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136
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Tomaz CT, Duarte D, Queiroz JA. Comparative study on the fractionation of cellulases on some hydrophobic interaction chromatography adsorbents. J Chromatogr A 2002; 944:211-6. [PMID: 11831755 DOI: 10.1016/s0021-9673(01)01224-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this work, a comparative study for the fractionation of Trichoderma reesei cellulases on five different hydrophobic interaction chromatography adsorbents (Butyl-Sepharose 4 FF, Phenyl-Sepharose 6 FF, Octyl-Sepharose 4 FF, Epoxy-Sepharose CL-6B and Polypropylene glycol-Sepharose CL-6B) is shown. The influence of the mobile phase composition on the chromatographic behaviour of T. reesei cellulases complex was evaluated using different concentrations of ammonium sulphate in the eluent buffer. A selective separation of beta-glucosidase with two-fold increase in specific activity and good recoveries of cellobiase activity were obtained with Butyl-Sepharose 4 FF and Phenyl-Sepharose 6 FF using 7% (w/v) ammonium sulphate in the eluent buffer. A beta-glucosidase fractionation was also obtained with Epoxy-Sepharose CL-6B, using 13% (w/v) of the salt in the mobile phase.
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137
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Diogo MM, Ribeiro SC, Queiroz JA, Monteiro GA, Tordo N, Perrin P, Prazeres DM. Production, purification and analysis of an experimental DNA vaccine against rabies. J Gene Med 2001; 3:577-84. [PMID: 11778904 DOI: 10.1002/jgm.218] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND The basic and applied research efforts devoted to the development of DNA vaccines must be accompanied by manufacturing processes capable of being scaled up and delivering a clinical-grade product. This work describes a rapid process of this kind, based on hydrophobic interaction chromatography (HIC) for the production of milligram quantities of an experimental DNA rabies vaccine. Its properties and protective activity are tested in comparison with the same plasmid DNA purified with a commercial kit. METHODS The experimental DNA vaccine encoding the rabies virus glycoprotein was amplified in vivo in Escherichia coli. The plasmid was isolated by alkaline lysis, pre-purified and concentrated by isopropanol and (NH4)2SO4 precipitation, and purified by HIC and dialysis. Product quality was controlled by using high-performance liquid chromatography (HPLC), Southern slot blotting, agarose gel electrophoresis, the kinetic-QCL Limulus amoebocyte lysate assay, and protein assays. The expression of the rabies virus glycoprotein was tested in vitro in neuroblastoma cells. The production of rabies-virus-neutralising antibodies and the protection against an intracerebral virus challenge were tested in mice. RESULTS One hundred and forty-two milligrams of the plasmid, with an HPLC purity greater than 99% were obtained from 4.5 l medium. Control analysis showed that the vaccine conforms to specifications in terms of impurities (endotoxins, genomic DNA, RNA, proteins). Furthermore, the final experimental vaccine induces rabies-virus-neutralising antibodies and protects mice against a rabies virus challenge. CONCLUSIONS This study demonstrates that the method developed for the purification of milligram amounts of plasmid delivers an endotoxin-free, experimental rabies DNA vaccine, with protective activity similar to that obtained with the vaccine purified using a commercial kit.
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MESH Headings
- Animals
- Antibodies, Viral/biosynthesis
- Chromatography, High Pressure Liquid
- Electrophoresis, Agar Gel
- Female
- Genetic Vectors
- Glycoproteins/analysis
- Injections, Intramuscular
- Injections, Intraventricular
- Kinetics
- Mice
- Mice, Inbred BALB C
- Plasmids
- Rabies/immunology
- Rabies/prevention & control
- Rabies Vaccines/administration & dosage
- Rabies Vaccines/genetics
- Rabies Vaccines/immunology
- Rabies Vaccines/isolation & purification
- Rabies virus/genetics
- Rabies virus/immunology
- Time Factors
- Transformation, Genetic
- Tumor Cells, Cultured
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- Vaccines, DNA/isolation & purification
- Viral Proteins/analysis
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138
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Abstract
In this article, an overview of hydrophobic interaction chromatography (HIC) of proteins is given. After a brief description of protein hydrophobicity and hydrophobic interactions, we present the different proposed theories for the retention mechanism of proteins in HIC. Additionally, the main parameters to consider for the optimization of fractionation processes by HIC and the stationary phases available were described. Selected examples of protein fractionation by HIC are also presented.
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139
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Diogo MM, Queiroz JA, Monteiro GA, Martins SA, Ferreira GN, Prazeres DM. Purification of a cystic fibrosis plasmid vector for gene therapy using hydrophobic interaction chromatography. Biotechnol Bioeng 2000; 68:576-83. [PMID: 10797245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The success and validity of gene therapy and DNA vaccination in in vivo experiments and human clinical trials depend on the ability to produce large amounts of plasmid DNA according to defined specifications. A new method is described for the purification of a cystic fibrosis plasmid vector (pCF1-CFTR) of clinical grade, which includes an ammonium sulfate precipitation followed by hydrophobic interaction chromatography (HIC) using a Sepharose gel derivatized with 1,4-butanediol-diglycidylether. The use of HIC took advantage of the more hydrophobic character of single-stranded nucleic acid impurities as compared with double-stranded plasmid DNA. RNA, denatured genomic and plasmid DNAs, with large stretches of single strands, and lipopolysaccharides (LPS) that are more hydrophobic than supercoiled plasmid, were retained and separated from nonbinding plasmid DNA in a 14-cm HIC column. Anion-exchange HPLC analysis proved that >70% of the loaded plasmid was recovered after HIC. RNA and denatured plasmid in the final plasmid preparation were undetectable by agarose electrophoresis. Other impurities, such as host genomic DNA and LPS, were reduced to residual values with the HIC column (<6 ng/microg pDNA and 0.048 EU/microg pDNA, respectively). The total reduction in LPS load in the combined ammonium acetate precipitation and HIC was 400,000-fold. Host proteins were not detected in the final preparation by bicinchoninic acid (BCA) assay and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with silver staining. Plasmid identity was confirmed by restriction analysis and biological activity by transformation experiments. The process presented constitutes an advance over existing methodologies, is scaleable, and meets quality standards because it does not require the use of additives that usually pose a challenge to validation and raise regulatory concerns.
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140
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Esquibel-King MA, Dias-Cabral AC, Queiroz JA, Pinto NG. Study of hydrophobic interaction adsorption of bovine serum albumin under overloaded conditions using flow microcalorimetry. J Chromatogr A 1999; 865:111-22. [PMID: 10674934 DOI: 10.1016/s0021-9673(99)01118-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The adsorption behavior of bovine serum albumin (BSA) on a Sepharose based hydrophobic interaction support has been studied. Flow microcalorimetry has been used to determine the heat of adsorption under overloaded chromatographic conditions. These data have been complemented with capacity factor and isotherm measurements to provide insight on the mechanisms of adsorption. The heat of adsorption data have confirmed that the hydrophobic interaction adsorption of BSA under linear isotherm conditions is driven by entropy changes. Under overloaded (non-linear) conditions, however, it has been shown that the changes in enthalpy can drive adsorption; this behavior is not evident from analyses of capacity factor data. It is postulated that for BSA adsorption on the Sepharose derivative of interest, attractive force interactions between adsorbed protein molecules drive the adsorption process under overloaded conditions in a high (NH4)2SO4 environment. It is further postulated that these interactions are due to a change in confirmation of the adsorbed protein under these conditions.
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141
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Tomaz CT, Queiroz JA. Studies on the chromatographic fractionation of Trichoderma reesei cellulases by hydrophobic interaction. J Chromatogr A 1999; 865:123-8. [PMID: 10674935 DOI: 10.1016/s0021-9673(99)00851-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This work reports new studies on cellulases fractionation by hydrophobic interaction chromatography. The purification procedure for the Trichoderma reesei cellulase complex consists of gel permeation chromatography on Sephadex G-25M followed by an ultrafiltration step. The concentrated enzyme solution was then fractionated on Sepharose CL-6B modified by covalent immobilization of 1,4-butanediol diglycidyl ether. The influence of the mobile phase composition on the chromatographic behaviour of the T. reesei cellulase complex was investigated. By using 13% (w/v) ammonium sulphate in eluent buffer, a selective separation of beta-glucosidase with a two-fold increase in specific activity and a recovery of 60% cellobiase activity were obtained. Other commercial hydrophobic supports (octyl- and phenyl-Sepharose) were also tested and compared under the same conditions.
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142
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Diogo MM, Queiroz JA, Monteiro GA, Prazeres DM. Separation and analysis of plasmid denatured forms using hydrophobic interaction chromatography. Anal Biochem 1999; 275:122-4. [PMID: 10542118 DOI: 10.1006/abio.1999.4297] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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143
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Diogo MM, Silva S, Cabral JM, Queiroz JA. Hydrophobic interaction chromatography of Chromobacterium viscosum lipase on polypropylene glycol immobilised on Sepharose. J Chromatogr A 1999; 849:413-9. [PMID: 10457439 DOI: 10.1016/s0021-9673(99)00619-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fractionation of Chromobacterium viscosum lipase was performed using a polypropylene glycol-Sepharose gel. The influence of mobile phase composition on the adsorption of lipase on the gel was studied and it was found that the retention of lipase depends on the salt used and increased with increasing the ionic strength. The retention was not strongly affected by changing the pH value of the mobile phase. By using 20% (w/v) ammonium sulphate in phosphate buffer a total retention of lipase on the column was obtained and by simply decreasing the ionic strength of the buffer, desorption of lipase could be achieved. The chromatographic purification of Chromobacterium viscosum lipase by hydrophobic interaction chromatography on Sepharose CL-6B modified by covalent immobilisation of 1,4-butanediol diglycidyl ether, polyethylene glycol and polypropylene glycol was also compared.
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145
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Diogo MM, Cabral JM, Queiroz JA. Preliminary study on hydrophobic interaction chromatography of Chromobacterium viscosum lipase on polypropylene glycol immobilized on Sepharose. J Chromatogr A 1998; 796:177-80. [PMID: 9513291 DOI: 10.1016/s0021-9673(97)01059-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The purification of Chromobacterium viscosum lipase was performed using a polypropylene glycol-Sepharose gel. The influence of the mobile phase composition on the chromatographic behaviour of Chromobacterium viscosum lipase was studied and it was found that the retention of lipase depends on the salt used and increased with ionic strength. Using 20% (w/v) ammonium sulphate in the eluent, a total retention of lipase on the column was obtained.
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146
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Zwingenberger K, Feldmeier H, Queiroz JA, Siqueira JG, Auto HF, Alencar JE, Bienzle U. Liver involvement in human schistosomiasis mansoni. Assessment by immunological and biochemical markers. Parasitol Res 1988; 74:448-55. [PMID: 3137558 DOI: 10.1007/bf00535145] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In 20 patients with hepatic or hepatosplenic schistosomiasis and 82 individuals infected with S. mansoni, but without liver enlargement, serum parameters reflecting the fibrotic process and hemodynamic alterations as well as immunomodulation were examined. Included as controls were 35 age- and sex-matched healthy individuals from the study region in Northeast Brazil. Peripheral blood cholylglycine levels in patients with hepatomegaly, reflecting the spillover of portal blood into the systemic circulation, were elevated 12-fold over values of patients without liver involvement. Procollagen-III-peptide, a cleavage product of collagen synthesis, was elevated in patients with hepatomegaly (P less than 0.001) but normal in uncomplicated cases. Immunomodulation was assessed by in vivo delayed hypersensitivity to recall antigens and by serum beta 2-microglobulin and neopterin, substances released in the context of lymphocyte activation. Neopterin, predominantly a macrophage product, was elevated most strikingly in hepatomegalic cases (P less than 0.001). The possible interrelation between altered immune responses and excess fibrogenesis is discussed.
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147
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Zwingenberger K, Queiroz JA, Poggensee U, Alencar JE, Valdegunas J, Esmeralda F, Feldmeier H. Efficacy of oxamniquine, praziquantel and a combination of both drugs in schistosomiasis mansoni in Brazil. Rev Inst Med Trop Sao Paulo 1987; 29:305-11. [PMID: 3136533 DOI: 10.1590/s0036-46651987000500007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
A randomized clinical trial was carried out to compare the efficacy of a low-dosage combination of oxamniquine (7.5 mg/kg) plus praziquantel (20 mg/kg) against either agent, oxamniquine (15 mg/kg) or praziquantel (40 mg/kg) alone, in the treatment of schistosomiasis mansoni in the Brazilian north-east. The drugs were randomly administered per os to 91 patients. Six and twelve months after treatment 89% of those admitted to the trial were reexamined by Kato-Katz method (ten slides) and MIF technique (one gram of stool) The achieved cure rates, as defined by absence of S. mansoni eggs in the faeces of individual patients at all points during the parasitological follow-up, were 81.8%, 81.2% and 67.6% for praziquantel, oxamniquine and the combination respectively. The reduction of eggs excretion in non cured patients six months after therapy ranged from 93.8-96.8% with praziquantel, 32.5-97% with oxamniquine and 76.9-99.5% with the combination. It is concluded that, at the used dosages, the three therapeutical regimens give similar and satisfactory results in the treatment of uncomplicated S. mansoni infection in Brazil.
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148
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Viana GS, Gadelha MG, Queiroz JA, Naidu TG, Shirachi DY. Immunological characterization of partially purified cholinesterase from ascitic fluid of Ehrlich tumor. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 1981; 19:819-22. [PMID: 6796507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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