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Biologic Drug Substance and Drug Product Manufacture
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Ajit S. Narang, Mary E. Krause, Shelly Pizarro, Joon Chong Yee
mAb production by recombinant protein expression started with hybridoma and Chinese hamster ovary (CHO) cells. Several rodent- and human-derived cells are also used for therapeutic protein expression. These include 3T3, BHK, HeLa, and HepG2. However, CHO cells remain the most frequently used cell line for mAb production. CHO cells present several advantages such as resilience (can be grown in various media environments and scaled-up easily), fast generation times, easily adapted to suspension cell culture (as opposed to adherent cell cultures), and characteristics that make them amenable for genetic modification (e.g. low chromosome number and ease of transfection and selection of transgene-expressing cells). Early mutagenesis studies led to the isolation of certain auxotrophs—mutants that require particular nutrients for maintaining growth and viability over long culture periods.
Selection and Improvement of Industrial Organisms for Biotechnological Applications
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
Auxotrophic mutants are those which lack the enzymes to manufacture certain required nutrients. Consequently, such nutrients must therefore be added to the growth medium. In contrast, the wild-type or prototrophic organisms possess all the enzymes needed to synthesize all growth requirements. Auxotrophic mutants are often used in industrial microbiology, e.g. for the production of amino acids, nucleotides, etc.
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Auxotroph is a mutant cell or micro-organism lacking one metabolic pathway present in the parental strain, and that consequently will not multiply on a minimal medium, but requires for growth the addition of a specific compound, such as an amino acid or a vitamin.
Biosafety and biosecurity in Synthetic Biology: A review
Published in Critical Reviews in Environmental Science and Technology, 2019
Lucía Gómez-Tatay, José M. Hernández-Andreu
Biocontainment measures include physical measures (engineering design of equipment, process and production plant) and biological means, among which inducible systems, auxotrophy and cellular circuits are the most established strategies. In inducible systems, the introduced genes are expressed only if a specific inducer is present. The inducer required is not common in the natural environment, so that if the organism escapes the lab, the engineered trait will not be expressed, avoiding any potential advantage given by the genetic construct. Auxotrophy implies that the organism is not able to produce a particular vital compound, which must be provided in its media. Cellular circuits are genetic constructs that can lead to cell death when activated (kill switches) or to the death of the new host in case of horizontal gene transfer (addiction modules). However, these strategies are not effective enough when they are used in isolation, since the evolutionary cost of bypassing or reverting the containment mechanism is very low. Multiple strategies and targets must therefore be combined, in what is called multi-layered containment (Torres, Krüger, Csibra, Gianni, & Pinheiro, 2016), although it must be taken into account that multi-layering increases complexity, thus making the device more prone to failure. Furthermore, precautions must be adopted such as not to incorporate antibiotic-resistance genes as markers for plasmid selection, in order to avoid their propagation (Wright, Stan, & Ellis, 2013). To date, there have been no reports in the scientific literature of an escape of synthetic organisms into the natural environment.