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Culture Parameters (culture + parameter)
Selected AbstractsHead and neck squamous cell carcinoma cell lines: Established models and rationale for selectionHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 2 2007Charles J. Lin BA Abstract Background. Head and neck squamous cell carcinoma (HNSCC) cell lines are important preclinical models in the search for novel and targeted therapies to treat head and neck cancer. Unlike many other cancer types, a wide variety of primary and metastatic HNSCC cell lines are available. An easily accessible guide that organizes important characteristics of HNSCC cell lines would be valuable for the selection of appropriate HNSCC cell lines for in vitro or in vivo studies. Methods. A literature search was performed. Results. Cell growth and culture parameters from HNSCC cell lines were catalogued into tables or lists of selected characteristics. Methods for establishing cancer cell lines and basic cell culture maintenance techniques were reviewed. Conclusions. A compendium of HNSCC cell line characteristics is useful for organizing the accumulating information regarding cell line characteristics to assist investigators with the development of appropriate preclinical models. © 2006 Wiley Periodicals, Inc. Head Neck, 2006 [source] High-level extracellular production of penicillin acylase by genetic engineering of Escherichia coliJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2001Wen-Jer Lin Abstract The extracellular production of penicillin acylase (PAC) in genetically engineered Escherichia coli by coexpression of the brp gene encoding bacteriocin release protein (BRP) and the pac gene was demonstrated. Cell physiology was affected while PAC was released into the medium, depending on the strategy for brp expression. The performance for the production and release of PAC was optimized by taking several culture parameters, including host, inducer (mitomycin C) concentration, and induction timing for brp expression, into consideration. The effect of PAC release on inclusion body formation was also investigated. It was observed that the amount of inclusion bodies was significantly affected by brp expression. A reason for the limitation of PAC production and a strategy for resolving this problem are proposed. © 2001 Society of Chemical Industry [source] Statistical analysis of optimal culture conditions for Gluconacetobacter hansenii cellulose productionLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2007S.A. Hutchens Abstract Aim:, The purpose of this study was to analyse the effects of different culture parameters on Gluconacetobacter hansenii (ATCC 10821) to determine which conditions provided optimum cellulose growth. Methods and Results:, Five culture factors were investigated: carbon source, addition of ethanol, inoculation ratio, pH and temperature. jmp Software (SAS, Cary, NC, USA) was used to design this experiment using a fractional factorial design. After 22 days of static culture, the cellulose produced by the bacteria was harvested, purified and dried to compare the cellulose yields. The results were analysed by fitting the data to a first-order model with two-factor interactions. Conclusions:, The study confirmed that carbon source, addition of ethanol, and temperature were significant factors in the production of cellulose of this G. hansenii strain. While pH alone does not significantly affect average cellulose production, cellulose yields are affected by pH interaction with the carbon source. Culturing the bacteria on glucose at pH 6·5 produces more cellulose than at pH 5·5, while using mannitol at pH 5·5 produces more cellulose than at pH 6·5. The bacteria produced the most cellulose when cultured on mannitol, at pH 5·5, without ethanol, at 20°C. Inoculation ratio was not found to be a significant factor or involved in any significant two-factor interaction. Significance and Impact of the Study:, These findings give insight into the conditions necessary to maximize cellulose production from this G. hansenii strain. In addition, this work demonstrates how the fractional factorial design can be used to test a large number of factors using an abbreviated set of experiments. Fitting a statistical model determined the significant factors as well as the significant two-factor interactions. [source] Degradation of an Fc-fusion recombinant protein by host cell proteases: Identification of a CHO cathepsin D proteaseBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009Flavie Robert Abstract A host-cell-related proteolytic activity was identified in a recombinant Fc-fusion protein production process. This report describes the strategy applied to characterize and isolate the enzyme responsible for this degradation by combining cell culture investigation and dedicated analytical tools. After isolation and sequencing of the clipped fragment generated in post-capture material, enzymatic activity was traced in different culture conditions, allowing identification of viable CHO cells as the source of protease. Inhibitors and pH screenings showed that the enzyme belongs to an aspartic protease family and is preferably active at acidic pH. The protease was isolated by purification on a pepstatin A column and characterized as a protein related to cathepsin D. An additional metallo-protease inhibited by EDTA was identified with an optimum activity at neutral pH. This study is an example of how quality and stability of therapeutic recombinant molecules are strongly influenced by cell culture parameters. Biotechnol. Bioeng. 2009; 104: 1132,1141. © 2009 Wiley Periodicals, Inc. [source] Technological progresses in monoclonal antibody production systemsBIOTECHNOLOGY PROGRESS, Issue 2 2010Maria Elisa Rodrigues Abstract Monoclonal antibodies (mAbs) have become vitally important to modern medicine and are currently one of the major biopharmaceutical products in development. However, the high clinical dose requirements of mAbs demand a greater biomanufacturing capacity, leading to the development of new technologies for their large-scale production, with mammalian cell culture dominating the scenario. Although some companies have tried to meet these demands by creating bioreactors of increased capacity, the optimization of cell culture productivity in normal bioreactors appears as a better strategy. This review describes the main technological progresses made with this intent, presenting the advantages and limitations of each production system, as well as suggestions for improvements. New and upgraded bioreactors have emerged both for adherent and suspension cell culture, with disposable reactors attracting increased interest in the last years. Furthermore, the strategies and technologies used to control culture parameters are in constant evolution, aiming at the on-line multiparameter monitoring and considering now parameters not seen as relevant for process optimization in the past. All progresses being made have as primary goal the development of highly productive and economic mAb manufacturing processes that will allow the rapid introduction of the product in the biopharmaceutical market at more accessible prices. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Optimization of primary culture condition for mesenchymal stem cells derived from umbilical cord blood with factorial designBIOTECHNOLOGY PROGRESS, Issue 2 2009Xiubo Fan Abstract Mesenchymal stem cells (MSCs) can not only support the expansion of hematopoietic stem cells in vitro, but also alleviate complications and accelerate recovery of hematopoiesis during hematopoietic stem cell transplantation. However, it proved challenging to culture MSCs from umbilical cord blood (UCB) with a success rate of 20,30%. Many cell culture parameters contribute to this outcome and hence optimization of culture conditions is critical to increase the probability of success. In this work, fractional factorial design was applied to study the effect of cell inoculated density, combination and dose of cytokines, and presence of serum and stromal cells. The cultured UCB-MSC-like cells were characterized by flow cytometry and their multilineage differentiation potentials were tested. The optimal protocol was identified achieving above 90% successful outcome: 2 × 106 cells/mL mononuclear cells inoculated in Iscove's modified Dulbecco's medium supplied with 10% FBS, 15 ng/mL IL-3, and 5 ng/mL Granulocyte-macrophage colony-stimulating factor (GM-CSF). Moreover, the UCB-MSC-like cells expressed MSC surface markers of CD13, CD29, CD105, CD166, and CD44 positively, and CD34, CD45, and human leukocyte antigens-DR (HLA-DR) negatively. Meanwhile, these cells could differentiate into osteoblasts, chondrocytes, and adipocytes similarly to MSCs derived from bone marrow. In conclusion, we have developed an efficient protocol for the primary culture of UCB-MSCs by adding suitable cytokines into the culture system. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Effects of Oxygen Transport on 3-D Human Mesenchymal Stem Cell Metabolic Activity in Perfusion and Static Cultures: Experiments and Mathematical ModelBIOTECHNOLOGY PROGRESS, Issue 4 2005Feng Zhao Human mesenchymal stem cells (hMSCs) have unique potential to develop into functional tissue constructs to replace a wide range of tissues damaged by disease or injury. While recent studies have highlighted the necessity for 3-D culture systems to facilitate the proper biological, physiological, and developmental processes of the cells, the effects of the physiological environment on the intrinsic tissue development characteristics in the 3-D scaffolds have not been fully investigated. In this study, experimental results from a 3-D perfusion bioreactor system and the static culture are combined with a mathematical model to assess the effects of oxygen transport on hMSC metabolism and proliferation in 3-D constructs grown in static and perfusion conditions. Cells grown in the perfusion culture had order of magnitude higher metabolic rates, and the perfusion culture supports higher cell density at the end of cultivation. The specific oxygen consumption rate for the constructs in the perfusion bioreactor was found to decrease from 0.012 to 0.0017 ,mol/106 cells/h as cell density increases, suggesting intrinsic physiological change at high cell density. BrdU staining revealed the noneven spatial distribution of the proliferating cells in the constructs grown under static culture conditions compared to the cells that were grown in the perfusion system. The hypothesis that the constructs in static culture grow under oxygen limitation is supported by higher YL/G in static culture. Modeling results show that the oxygen tension in the static culture is lower than that of the perfusion unit, where the cell density was 4 times higher. The experimental and modeling results show the dependence of cell metabolism and spatial growth patterns on the culture environment and highlight the need to optimize the culture parameters in hMSC tissue engineering [source] Specific Effects of Synthetic Oligopeptides on Cultured Animal Cells,BIOTECHNOLOGY PROGRESS, Issue 1 2002Franti, ek Fran Synthetic oligopeptides, tri- to pentaglycine and tri- and tetraalanine, were found to enhance viable cell density and culture viability when applied at concentrations higher than milllimolar to the cultures of a model hybridoma line. Oligoalanines, in addition, enhanced monoclonal antibody yields. Oligoglycines promoted solely the cell growth, unless the batch culture was fed with a medium concentrate. Examination of the effects of various tripeptides composed of glycine, alanine, serine, threonine, lysine, and histidine showed that some of the peptides promoted the growth of the culture, while other peptides suppressed the growth and enhanced the monoclonal antibody yield. Determination of the levels of amino acids and peptides in culture media indicated that the observed changes of culture parameters were caused by intact peptide molecules, rather than by amino acids liberated from the peptides by enzymic cleavage. [source] | ||||||||||