Abstract:
:The solution structure of plasmid DNA is known to be a strong function of solution conditions due to intramolecular electrostatic interactions between the charged phosphate groups along the DNA backbone. The objective of this work was to determine whether it was possible to enhance the use of ultrafiltration for separation of different plasmid isoforms by proper selection of the solution ionic strength and ion type. Experiments were performed with a 3.0 kbp plasmid using composite regenerated cellulose ultrafiltration membranes. The transmission of the linear isoform was nearly independent of solution ionic strength, but increased significantly with increasing filtrate flux due to the elongation of the highly flexible plasmid in the converging flow field into the membrane pores. In contrast, the transmission of the open-circular and supercoiled plasmids both increased with increasing NaCl or MgCl2 concentration due to the change in plasmid size and conformational flexibility. The effect of ionic strength was greatest for the supercoiled plasmid, providing opportunities for enhanced purification of this therapeutically active isoform. This behavior was confirmed using experiments performed with binary mixtures of the different isoforms. These results clearly demonstrate the potential for enhancing the performance of membrane systems for plasmid DNA separations by proper selection of the ionic conditions.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Li Y,Currie D,Zydney ALdoi
10.1002/bit.25836subject
Has Abstractpub_date
2016-04-01 00:00:00pages
783-9issue
4eissn
0006-3592issn
1097-0290journal_volume
113pub_type
杂志文章abstract::The secretion of heterologous IgG proteins in the baculovirus-insect cell expression system is accompanied by substantial insoluble immunoglobulin in the infected cells. The accumulation of these insoluble forms suggests a limitation in the processing and secretory pathway of the infected cells. As a result, cytosolic...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:1998-04-20 00:00:00
abstract::Production of cellulase using solid culture systems of Trichoderma reesei QM9414 and Sporotrichum cellulophilum on wheat bran was studied. By using moisture-controlled solid culture equipment, the effect of water content of wheat bran on cell growth and cellulase production was investigated. Cellular biomass grown on ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260271008
更新日期:1985-10-01 00:00:00
abstract::Two-dimensional image analysis was applied to counting, sizing, and density determinations of granules in full-scale and laboratory-scale upflow anaerobic sludge blanket (UASB) digesters. An advantage of this technique for monitoring laboratory-scale digester sludge is the small amount of material required for analysi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420303
更新日期:1993-07-01 00:00:00
abstract::Lectin-like function was demonstrated in this study for a novel water-soluble polymer with phenylboronic acid residues (poly (AAPBA-DMAm)), which induced appreciable proliferation of murine spleen lymphocytes with an increased expression of interleukin-2 (IL-2) receptor on their surface. Consequently, boosted prolifer...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:
更新日期:2001-02-05 00:00:00
abstract::The immobilization of dextransucrase in Ca-alginate beads relies on the close association between dextran polymer and dextransucrase. However, high amounts of dextran in the enzyme preparation drastically limit the specific activity of the immobilized enzyme (4 U/mL of alginate beads). Moreover, even in the absence of...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1183
更新日期:2001-11-05 00:00:00
abstract::The efficiency of a versatile in vivo cascade involving a promiscuous alcohol dehydrogenase, obtained from a biodiversity search, and a Baeyer-Villiger monooxygenase was enhanced by the independent control of the production level of each enzyme to produce ε-caprolactone and 3,4-dihydrocoumarin. This goal was achieved ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27133
更新日期:2019-11-01 00:00:00
abstract::Product inhibition of biological production systems is a widely observed phenomenon with prominent implications for the design and ultimately the success of biotechnological processes. In order to investigate whether such effects could limit the maximal concentrations in the production of the beta-lactamase inhibitor ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21783
更新日期:2008-06-15 00:00:00
abstract::NS0, a nonsecreting mouse myeloma cell, is a major host line used for recombinant antibody production. These cells have a cholesterol-dependent phenotype and rely on an exogenous supply of cholesterol for their survival and growth. To better understand the physiology underlying cholesterol dependence, we compared NS0 ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20429
更新日期:2005-06-05 00:00:00
abstract::A comprehensive study of the application of continuous zone electrophoresis to preparative separation of proteins in free solution is presented. First, the influence of electric field strength, buffer residence time in the chamber, sample flow rate, and sample concentration on separation resolution and throughput were...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260420707
更新日期:1993-09-20 00:00:00
abstract::The hydrolysis of lactose by a beta-galactosidase from the thermophilic microorganism Thermus sp. strain T2, both in solution and immobilized on a commercial silica-alumina, has been studied. The enzyme has been previously produced by Escherichia coli JM101 harboring the plasmid pBGT1, which contains the codifying gen...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.10466
更新日期:2003-01-20 00:00:00
abstract::The rate of diffusion of serum albumin (MW 6.9 x 10(4) D) out of beads of calcium alginate gels depends upon the concentration and uronic acid composition of the alginate (ManA/GulA ratio), the conditions under which the beads are produced, the pH, and the temperature. The diffusion coefficient decreases with increasi...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260390210
更新日期:1992-01-20 00:00:00
abstract::The major objectives for preparative protein chromatography are maximal loading and increased flow rate while maintaining defined resolution. Conventionally a series of chromatographic experiments are performed and the optimal conditions are selected according to the separation criteria. Computer-aided process design ...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0290(19961020)52:2<223::AID-BIT
更新日期:1996-10-20 00:00:00
abstract::Animal-derived serum is an essential media supplement for mammalian cells in cell culture. For a number of reasons including cost, regulatory concerns, lot inconsistency, potential contamination with adventitious agents, and down-stream processing it is desirable to eliminate the use of serum. Existing protocols desig...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.21707
更新日期:2008-04-15 00:00:00
abstract::An automated system with semi on-line monitoring of glucose, lactic acid, protein, and optical density during lactic acid fermentations, is set up to study the dynamics of lactic acid bacteria. The analyzers for glucose, lactic acid, and protein are based on flow injection analysis (FIA). The system consists of a labo...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260330908
更新日期:1989-04-05 00:00:00
abstract::Physical damage of animal cells in suspension culture, due to stirring and sparging, is coupled with complex metabolic responses. Nylon microcapsules, therefore, were used as a physical model to study the mechanisms of damage in a stirred bioreactor and in a bubble column. Microcapsule breaskage folowed first-order ki...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260401018
更新日期:1992-12-05 00:00:00
abstract::Enzymatic bioreactors with both high flow characteristics and mechanical stability based on macroporous poly(2-vinyl-4, 4-dimethylazlactone-co-acrylamide-co-ethylene dimethacrylate) monoliths have been prepared. Covalent immobilization of trypsin on these support is achieved in a single reaction step using the azlacto...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990105)62:1<30::aid-bit4
更新日期:1999-01-05 00:00:00
abstract::This study deals with the use of an upward gas/liquid slug flow to reduce tubular mineral membrane fouling. The injection of air into the feedstream is designed to create hydrodynamic conditions that destabilize the cake layer over the membrane surface inside the filtration module complex. Experimental study was carri...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19980405)58:1<47::aid-bit5
更新日期:1998-04-05 00:00:00
abstract::N-linked glycan distribution affects important end-use characteristics such as the bioactivity and efficacy of many therapeutic proteins, (including monoclonal antibodies), in vivo. Yet, obtaining desired glycan distributions consistently during batch-to-batch production can be challenging for biopharmaceutical manufa...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25251
更新日期:2014-10-01 00:00:00
abstract::Axial and radial oxygen depletion are believed to be critical scale-limiting factors in the design of cell culture hollow fiber bioreactors. A mathematical analysis of oxygen depletion has been performed in order to develop effectiveness factor plots to aid in the scaling of hollow fiber bioreactors with cells immobil...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260370112
更新日期:1991-01-05 00:00:00
abstract::A novel multivariable control strategy is developed for alcohol (ethanol and n-pentanol) concentrations in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(HB-co-HV), a biodegradable polymer by Paracoccus denitrificans ATCC 1774. This controller, which is developed to control the mole fraction of P(HB...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.1101
更新日期:2001-07-20 00:00:00
abstract::The use of recombinant adenoviral vectors for vaccination and gene therapy requires the development of purification processes that are cost-effective, scalable, and capable of robust host cell DNA clearance. An adenovirus purification process was developed which incorporates selective precipitation of host cell DNA, e...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20406
更新日期:2005-07-05 00:00:00
abstract::The emissions of nitrous oxide (N(2)O) and nitric oxide (NO) from biological nitrogen removal (BNR) operations via nitrification and denitrification is gaining increased prominence. While many factors relevant to the operation of denitrifying reactors can influence N(2)O and NO emissions from them, the role of differe...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22704
更新日期:2010-06-15 00:00:00
abstract::For clinical trials, large amounts of high-titer retroviral supernatants are required. However, retroviral concentration is relatively low compared with other viral vectors. Moreover, less than half of retroviral vectors suspended in a collected supernatant are infectious because of their short half-lives. In this stu...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20435
更新日期:2005-05-05 00:00:00
abstract::Nitrifying bacteria, cyanobacteria, and algae are important microorganisms in open pond wastewater treatment systems. Nitrification involving the sequential oxidation of ammonia to nitrite and nitrate, mainly due to autotrophic nitrifying bacteria, is essential to biological nitrogen removal in wastewater and global n...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22860
更新日期:2010-12-15 00:00:00
abstract::The DeltaSf of one unit carbon formula weight of Escherichia coli K-12 cells, when grown on succinic acid, was calculated to be -80.13 J/deg. This value could then be used to calculate the entropy change accompanying the anabolism and metabolism of succinic acid to be 30.82 J/deg and 32.40 J/mol deg, respectively. The...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260410405
更新日期:1993-02-20 00:00:00
abstract::In a previous paper, the overall or macrokinetics of the immobilized glucose oxidase--catalase system has been presented. In this paper a detailed analysis of the interaction of diffusion and reaction in this system will be presented. The mathematical treatment includes two consecutive reactions with two-substrate kin...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260211112
更新日期:1979-11-01 00:00:00
abstract::A poly(acrylic acid)-polyethylene graft copolymer was prepared and used initially to couple to acid phosphatase, using soluble carbodiimides. Yields which were quite good were obtained with CMC but not with EDAC. The copolymers was used to couple trypsin using EEDQ. Several organic solvents were investigated for the p...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260240610
更新日期:1982-06-01 00:00:00
abstract::The use of cell numbers rather than mass to quantify the size of the biotic phase in animal cell cultures causes several problems. First, the cell size varies with growth conditions, thus yields expressed in terms of cell numbers cannot be used in the normal mass balance sense. Second, experience from microbial system...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0290(19971120)56:4<372::AID-BIT
更新日期:1997-11-20 00:00:00
abstract::A soil with aged contamination from lubricating oil (LO) and polychlorinated biphenyls (PCBs) was treated in a bioslurry reactor to investigate in-soil biosurfactant production by Pseudomonas aeruginosa, the most abundant indigenous, culturable, hydrocarbon-degrading microorganism. After 2 days of growth on LO, a depl...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20295
更新日期:2004-12-30 00:00:00
abstract::We developed a model for nutrient removal in an aerobic granular sludge system. This model can quantitatively describe the start-up of the system by coupling a model for studying the population dynamics of the granules in the reactor (reactor-scale model) and a model for studying the microbial community structure in t...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.25331
更新日期:2015-01-01 00:00:00