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Operator training in recombinant protein production using a structured simulator model. J Biotechnol 2014; 177:53-9. [PMID: 24630856 DOI: 10.1016/j.jbiotec.2014.02.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 01/22/2023]
Abstract
Model-based operator training simulators (OTS) could be powerful tools for virtual training of operational procedures and skills of production personnel in recombinant protein processes. The applied model should describe critical events in the bioprocess so accurately that the operators' ability to observe and alertly act upon these events is trained with a high degree of efficiency. In this work is shown how this is accomplished in a structured multi-compartment model for the production of a recombinant protein in an Escherichia coli fed-batch process where in particular the induction procedure, the stress effects and overflow metabolism were highlighted. The structured model was applied on the OTS platform that virtually simulated the operational bioreactor procedures in real or accelerated time. Evaluation of training using the model-based OTS showed that trained groups of operators exhibited improved capability compared with the untrained groups when subsequently performing real laboratory scale cultivations. The results suggest that this model-based OTS may provide a valuable resource for enhancing operator skills in large scale recombinant protein manufacturing.
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2
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Laffend L, Shuler ML. Ribosomal protein limitations in Escherichia coli under conditions of high translational activity. Biotechnol Bioeng 2012; 43:388-98. [PMID: 18615722 DOI: 10.1002/bit.260430507] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Details of the mechanism for ribosome synthesis have been incorporated in the single-cell Escherichia coli model, which enable us to predict the amount of protein synthesizing machinery under different environmental conditions. The predictions agree quite well with available experimental data. The model predicts that ribosomal protein limitations are important when the translational apparatus is in high demand. Ribosomal RNA synthesis is induced by an increase in translational activity, which, in turn, stimulates ribosomal protein synthesis. However, as the demand increases still more, the ribosomal protein mRNA must compete with the plasmid mRNA for ribosomes, and the efficiency of translation of ribosomal proteins is reduced. (c) 1994 John Wiley & Sons, Inc.
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Affiliation(s)
- L Laffend
- School of Chemical Engineering, Cornell University, Ithaca, New York 14853
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3
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Nielsen J, Nikolajsen K, Villadsen J. Structured modeling of a microbial system: II. Experimental verification of a structured lactic acid fermentation model. Biotechnol Bioeng 2010; 38:11-23. [PMID: 18600693 DOI: 10.1002/bit.260380103] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A two-compartment model for the lactic acid fermentation with Streptococcus cremoris is experimentally verified. The seven parameters of the model are determined using steady-state chemostat data at varying values of dilution rate, D, but with a constant feed concentration, s(f), of a single carbohydrate source (glucose, lactose, or galactose), and a constant feed concentration of s(Nf) of the N source. Steady-state measurements of the RNA content at different exit concentrations, s, of the carbohydrate are included to calculate kinetic parameters that determine the cell composition for varying operating conditions. The model is tested using data from a large set of steady-state and non-steady-state experiments: batch fermentations and step and pulse experiments in a chemostat. Both qualitatively and quantitatively the major features of the model are confirmed: the external substrates enter into intracellular high-energy building blocks, and lactic acid is formed as a by-product of these reactions. Cell growth depends on the fraction of active components (X(A)) of the cell and is not accompanied by lactic acid production. Possible model modifications are discussed, primarily to obtain a better description of lactic acid fermentation at nongrowth conditions.
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Affiliation(s)
- J Nielsen
- Department of Biotechnology, Technical University of Denmark, Lyngby, Denmark
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PATNAIK P. SENSITIVITY OF RECOMBINANT FERMENTATION WITH RUN-AWAY PLASMIDS: A STRUCTURED ANALYSIS OF THE EFFECT OF DILUTION RATE. CHEM ENG COMMUN 2007. [DOI: 10.1080/00986449508936287] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- P.R. PATNAIK
- a Institute of Microbial Technology , P.O. Box 1304, Sector 39-A, Chandigark, 160014, India
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5
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Suthers PF, Gourse RL, Yin J. Rapid responses of ribosomal RNA synthesis to nutrient shifts. Biotechnol Bioeng 2007; 97:1230-45. [PMID: 17216653 DOI: 10.1002/bit.21318] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A major challenge in systems biology is to integrate our mechanistic understanding of gene regulation to predict quantitatively how cells will respond to environmental changes. Living cells respond rapidly to the availability of nutrients in part by altering production of ribosomal RNA (rRNA), a limiting component in the biosynthesis of ribosomes. Studies of rRNA transcription by the RNA polymerase of Escherichia coli have identified regulatory roles for guanosine tetraphosphate (ppGpp), the initiating nucleotide, and the protein DksA. To what extent findings from in vitro studies can be used to quantitatively predict in vivo responses to changing nutrient environments is unknown. We developed a mechanistic mathematical model for rRNA transcriptional responses to such changes. Our model accounts for binding of RNAP to its rRNA promoter to form a closed complex, isomerization from a closed complex to an open complex, reversible incorporation of the initiating NTP (iNTP), transcript elongation, and clearance of the promoter. Further, the model incorporates interactions between ppGpp and DksA with transcription intermediates, and it includes an empirical correction to account for salt effects. The model biophysical parameters were determined using 33 single- and multi-round transcription experiments spanning 487 in vitro measurements. By incorporating in vivo measurements of ppGpp and ATP, the model correctly predicted rRNA production rates for cellular responses to nutrient upshifts, downshifts, and outgrowth into fresh medium. Inclusion of DksA was essential in all three cases. Our work provides a foundation for using data-driven computational models to predict the kinetics of in vivo transcriptional responses.
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Affiliation(s)
- Patrick F Suthers
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, WI 53706-1607, USA
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6
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Tang S, Chen J, Zhang Z. Structured models for recombinant human interleukin-11 fermentation. Biochem Eng J 2007. [DOI: 10.1016/j.bej.2007.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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RUGGERI† BERNARDO, SASSI GUIDO. ON THE MODELLING APPROACHES OF BIOMASS BEHAVIOUR IN BIOREACTOR. CHEM ENG COMMUN 2007. [DOI: 10.1080/00986449308936148] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- BERNARDO RUGGERI†
- a Dip. Scienza dei Materiali ed Ingegneria Chimica , Politecnico di Torino, c.so Duca degli Abruzzi 24, Torino, 10122, Italy
| | - GUIDO SASSI
- a Dip. Scienza dei Materiali ed Ingegneria Chimica , Politecnico di Torino, c.so Duca degli Abruzzi 24, Torino, 10122, Italy
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Abstract
Models of single cells, cell populations, and cultures can be most useful in organizing information in a comprehensive system description, as well as in optimizing and controlling actual production operations. Models discussed in this article are of various degrees of biological structure and mathematical complexity. The models are developed based on the biomass formation, substrate consumption, and product formation. the potentials asn the limitations of all the models have been reported. The parameter estimation by different methods has been discussed in this communication. These parameters will be helpful to explore the areas where future-modeling studies may be especially valuable.
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Affiliation(s)
- Mani Thilakavathi
- Biochemical Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, India
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9
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New concepts for quantitative bioprocess research and development. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2006. [DOI: 10.1007/bfb0102335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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10
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Zheng ZY, Yao SJ, Lin DQ. Using a kinetic model that considers cell segregation to optimize hEGF expression in fed-batch cultures of recombinant Escherichia coli. Bioprocess Biosyst Eng 2005; 27:143-52. [PMID: 15806383 DOI: 10.1007/s00449-004-0376-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 06/30/2004] [Indexed: 11/29/2022]
Abstract
Growth inhibition of recombinant Escherichia coli during the expression of human epidermal growth factor was observed. The recombinant cells could be segregated into three populations based on their cell division and plasmid maintenance abilities: dividing and plasmid-bearing cells, dividing and plasmid-free cells, and viable-but-non-culturable (VBNC) cells. Fed-batch fermentations were performed to investigate the effect of cell segregation on the kinetics of growth and foreign protein production. The results showed that a low concentration of inducer caused weak induction, whereas high levels cause strong induction, resulting in cells segregating into VBNC bacteria and producing a low foreign protein yield. A kinetic model for cell segregation was proposed and its predictions correlated well with experimental data for cell growth and protein expression. The optimal induction strategy could then be predicted by the model, and this prediction was then verified by experimentally deriving the conditions necessary for maximum expression of recombinant protein.
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Affiliation(s)
- Zhi-Yong Zheng
- Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China
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11
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Arga K, Çakır T, Pir P, Özer N, Altıntaş M, Ülgen KÖ. Transfer function approach in structured modeling of recombinant yeast utilizing starch. Process Biochem 2004. [DOI: 10.1016/s0032-9592(03)00246-2] [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: 11/17/2022]
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12
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Zelić B, Vasić-Racki D, Wandrey C, Takors R. Modeling of the pyruvate production with Escherichia coli in a fed-batch bioreactor. Bioprocess Biosyst Eng 2004; 26:249-58. [PMID: 15085423 DOI: 10.1007/s00449-004-0358-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 03/17/2004] [Indexed: 11/27/2022]
Abstract
A family of 10 competing, unstructured models has been developed to model cell growth, substrate consumption, and product formation of the pyruvate producing strain Escherichia coli YYC202 ldhA::Kan strain used in fed-batch processes. The strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate (using glucose as the carbon source) resulting in an acetate auxotrophy during growth in glucose minimal medium. Parameter estimation was carried out using data from fed-batch fermentation performed at constant glucose feed rates of q(VG)=10 mL h(-1). Acetate was fed according to the previously developed feeding strategy. While the model identification was realized by least-square fit, the model discrimination was based on the model selection criterion (MSC). The validation of model parameters was performed applying data from two different fed-batch experiments with glucose feed rate q(VG)=20 and 30 mL h(-1), respectively. Consequently, the most suitable model was identified that reflected the pyruvate and biomass curves adequately by considering a pyruvate inhibited growth (Jerusalimsky approach) and pyruvate inhibited product formation (described by modified Luedeking-Piret/Levenspiel term).
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Affiliation(s)
- B Zelić
- Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, 10000 Zagreb, Croatia.
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Modeling of the induced expression for high-level production of a foreign protein by recombinant E. coli under the control of the T7 phage promoter. Process Biochem 2003. [DOI: 10.1016/s0032-9592(03)00077-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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14
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Patnaik P. An integrated hybrid neural system for noise filtering, simulation and control of a fed-batch recombinant fermentation. Biochem Eng J 2003. [DOI: 10.1016/s1369-703x(02)00195-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Buchholz A, Hurlebaus J, Wandrey C, Takors R. Metabolomics: quantification of intracellular metabolite dynamics. BIOMOLECULAR ENGINEERING 2002; 19:5-15. [PMID: 12103361 DOI: 10.1016/s1389-0344(02)00003-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The rational improvement of microbial strains for the production of primary and secondary metabolites ('metabolic engineering') requires a quantitative understanding of microbial metabolism. A process by which this information can be derived from dynamic fermentation experiments is presented. By applying a substrate pulse to a substrate-limited, steady state culture, cellular metabolism is shifted away from its metabolic steady state. With the aid of a rapid sampling and quenching routine it is possible to take 4-5 samples per second during this process, thus capturing the metabolic response to this stimulus. Over 30 metabolites, nucleotides and cofactors from Escherichia coli metabolism can be extracted and analysed using a range of different techniques, for example enzymatic assays, HPLC and LC-MS methods. Using different substrates as limiting and pulse-substrates (glucose, glycerol), different metabolic pathways and substrate uptake systems are investigated. The resulting plots of intracellular metabolite concentrations against time serve as a data basis for modelling microbial metabolic networks.
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Affiliation(s)
- Arne Buchholz
- Institute of Biotechnology 2, Forschungszentrum Jülich, Germany
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16
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Baheri HR, Hill GA, Roesler WJ. Modelling plasmid instability in batch and continuous fermentors. Biochem Eng J 2001; 8:45-50. [PMID: 11356370 DOI: 10.1016/s1369-703x(00)00135-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The probability of complete loss of plasmid material from plasmid bearing cells undergoing active growth has been modelled and incorporated into predictions for the dynamic concentrations of plasmid bearing cells in both batch and continuous flow, stirred tank bioreactors. The new model is based on an extension of the well-used model of Imanaka and Aiba [Ann. New York Acad. Sci. 369 (1981) 1] and is relatively easy to use compared to complex structured models. The new model predicts that both accelerating and decelerating rates of plasmid loss occur in both batch and continuous flow operation, and agrees well with data collected here and published earlier by others.
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Affiliation(s)
- H R. Baheri
- Department of Chemical Engineering and Petroleum Engineering, 2500 University Drive NW, AB, T2N 1N4, Calgary, Canada
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17
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Patnaik P. Investigation of induction effect on the steady state performance of a continuous fermentation for recombinant β-ga1actosidase. Process Biochem 2001. [DOI: 10.1016/s0032-9592(01)00147-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Tamerler C, Ulgen K, Kirdar B, Ilsen Önsan Z. A structured model for intracellular EcoRI endonuclease production by recombinant E. coli 294. Process Biochem 2001. [DOI: 10.1016/s0032-9592(00)00255-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Patnaik PR. Optimizing initial plasmid copy number distribution for improved protein activity in a recombinant fermentation. Biochem Eng J 2000; 5:101-107. [PMID: 10817814 DOI: 10.1016/s1369-703x(99)00058-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recombinant bacterial cells in a fermentation broth rarely contain the same number of plasmids, even though this simplification is often used. Recent work has however indicated limitations of the simplified approach. Based on these studies, the distribution of plasmid copy numbers per cell has been represented macroscopically here in a Gaussian form for the fraction of biomass as a function of the copy number. Applying this distribution and an experimentally validated kinetic model to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) synthesis by Escherichia coli containing the plasmid pBR Eco gap, it is seen that GAPDH production in a batch fermentation is maximized by a particular initial (non-zero) copy number variance and an optimal duration. To implement this distribution in a bioreactor, it is suggested that the profile may be discretized, inocula corresponding to the mean copy number of each fraction prepared, and then combined to obtain the seed culture.
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Affiliation(s)
- PR Patnaik
- Institute of Microbial Technology, Sector 39-A, Chandigarh, India
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20
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Ramírez DM, Bentley WE. Characterization of stress and protein turnover from protein overexpression in fed-batch E. coli cultures. J Biotechnol 1999; 71:39-58. [PMID: 10483100 DOI: 10.1016/s0168-1656(99)00014-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A structured kinetic model that accounts for proteolytic degradation due to recombinant protein overexpression is introduced and its performance evaluated by comparison with previously reported fed-batch experimental data. This mathematical model contains an additional pool for a generic key precursor (in our case phenylalanine), an improved IPTG transport term, a phenylalanine transport term, and a variable protein turnover expression that accounts for proteolytic activity. The model predictions concerning proteolytic activity, glucose level, and cell growth are in very good agreement with an amino acid depletion hypothesis. Cultures exposed to greater stress showed higher and/or longer proteolysis, whereas less overall proteolytic activity was observed when the effect of induction was somewhat ameliorated.
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Affiliation(s)
- D M Ramírez
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, College Park 20742, USA
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21
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22
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Sani RK, Chakraborti S, Sobti RC, Patnaik PR, Banerjee UC. Characterization and some reaction-engineering aspects of thermostable extracellular beta-galactosidase from a new Bacillus species. Folia Microbiol (Praha) 1999; 44:367-71. [PMID: 10983230 DOI: 10.1007/bf02903706] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new strain of Bacillus sp. was isolated from a hot water spring in India. This strain generated a high activity of extracellular beta-galactosidase at 37 degrees C in shake flasks. The beta-galactosidase activity was found to increase continuously but the production rate was slower than with some other organisms reported in the literature. There were noteworthy differences in the time-domain profiles of bacterial concentration and beta-galactosidase activity when the starting concentration of substrate (glucose) was tripled from 10 g/L. These differences may be explained in terms of the relative rates of enzyme synthesis and its diffusion across the cell wall. The enzyme produced by this organism is more stable than other beta-galactosidases; its half-life is 408 h at 50 degrees C and 94 h at 55 degrees C, while the reported enzymes showed perceptible loss of activity within 2 h.
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Affiliation(s)
- R K Sani
- Institute of Microbial Technology, Chandigarh, India
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23
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Analysis of the effect of interruptions in substrate inflow on a fed-batch fermentation with recombinant bacteria. Biochem Eng J 1998. [DOI: 10.1016/s1369-703x(97)00090-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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A recurrent neural network for a fed-batch fermentation with recombinant Escherichia coli subject to inflow disturbances. Process Biochem 1997. [DOI: 10.1016/s0032-9592(96)00081-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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25
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Kazan D, Çamurdan A, Hortaçsu A. The effect of glucose concentration on the growth rate and some intracellular components of a recombinant E. coli culture. Process Biochem 1995. [DOI: 10.1016/0032-9592(95)85008-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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26
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27
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Bailey JE. Host-vector interactions in Escherichia coli. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 1993; 48:29-52. [PMID: 8460576 DOI: 10.1007/bfb0007195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Introduction of a DNA vector into E. coli for the purposes of cloned gene expression can perturb native cell functions at many levels. The presence of foreign DNA can alter regulation of chromosomal DNA replication, regulation of transcription of chromosomal genes, ribosome functions and RNA turnover, activities of regulatory proteins, chaperone and protease levels, membrane energetics and protein post-translational processing, as well as energy and intermediary metabolism of the cell. The combined effects of these interactions on the metabolic characteristics of the host-vector system have major implications for yields of cloned biotechnological products and interactions of genetically engineered organisms with their environment.
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Affiliation(s)
- J E Bailey
- Department of Chemical Engineering, California Institute of Technology, Pasadena 91125
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Nordström K, Uhlin BE. Runaway–Replication Plasmids as Tools to Produce Large Quantities of Proteins from Cloned Genes in Bacteria. Nat Biotechnol 1992; 10:661-6. [PMID: 1368887 DOI: 10.1038/nbt0692-661] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Here we review the properties and uses of runaway-replication vectors, a class of versatile plasmids discovered and developed in Escherichia coli. They are based on the IncFII plasmid, R1, in which an antisense RNA (CopA RNA) negatively controls the formation of a protein that is rate-limiting for replication. The copy number of the plasmid is determined by the balance between the rates of formation of CopA RNA and RepA mRNA. A small increase in the rate of formation of the latter drastically reduces the rate of formation of CopA RNA due to convergent transcription, which may lead to a total loss of copy number control (runaway replication), resulting in massive DNA amplification, and plasmid copy numbers up to 1000 per genome. Since this amplification occurs in the presence of protein synthesis, the protein that is encoded by a cloned gene can also be amplified, and may constitute 10-50% of the total protein.
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Affiliation(s)
- K Nordström
- Department of Microbiology, Uppsala University, Sweden
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30
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Strudsholm K, Damgaard J, Emborg C. Application of statistical experimental designs in computer simulations of run-away fermentations. Bioprocess Biosyst Eng 1992. [DOI: 10.1007/bf01254226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Strudsholm K, Nielsen J, Emborg C. Product formation during batch fermentation with recombinant Escherichia coli containing a runaway plasmid. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/bf01254234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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