E. coli Expression Systems: Host Selection, Vectors, and Industrial Titers
Escherichia coli Expression Systems
Advantages of Microbial Expression Systems
Bacterial and yeast systems share several advantages over mammalian expression systems:
- Higher growth rate and cell densities.
- Robustness at the cellular level.
- High expression levels.
- Simple cultivation and are easy to scale-up.
The selection of the appropriate expression system is determined by the characteristics of the target protein or product.
Why E. coli Dominates Microbial Expression
E. coli has dominated microbial expression
Read MoreCellular Transport Mechanisms and Concentration Gradients
Solution Concentration and Particle Movement
Many essential chemical reactions take place in the cytoplasm and aqueous solutions.
- Solution: A solute dissolved in a solvent.
- Concentration: The amount of solute in proportion to the amount of solvent in a solution.
- All particles in a solution possess kinetic energy, resulting in continuous random movement.
The Principle of Diffusion
Molecules and ions in a fluid are in continuous, random motion due to their kinetic energy. Diffusion is the net movement of
Read MorePlant Tissue Culture Technology: Methods and Applications
Introduction to Plant Tissue Culture (PTC)
Plant tissue culture (PTC), developed around the 1950s, was a significant addition to plant breeding methods. Conventional breeding techniques often struggled to meet the required demand for crops, making tissue culture a major advancement in breeding practices.
PTC is defined as the in vitro aseptic culture of cells, tissues, or whole plants under controlled nutritional and environmental conditions, primarily used to produce clones of plants.
The Principle
Read MoreBioprocess Scale-Up & Scale-Down: Industrial Optimization
Bioprocess Scaling Up: Lab to Industrial Production
Bioprocess scaling up is the methodology used to develop an industrial bioprocess from knowledge acquired at the laboratory scale, often based on mathematical and physical models.
Approaches to Bioprocess Scaling Up
Scaling up can be approached in two primary ways:
- Increasing the number of reactors: This method carries no risk of scaling errors since all reactors are identical. However, it incurs significant expenses for monitoring and managing numerous
Boosting Bioproduction: Mutant Isolation & Permeability
Optimizing Primary Metabolite Production
The isolation of mutants that produce an improved level of primary metabolites is a crucial process in biotechnology and microbial fermentation. Through mutagenesis techniques, genetic variations are introduced into microorganisms. These mutations can lead to significantly enhanced production of essential primary metabolites, such as amino acids, organic acids, vitamins, or nucleotides, which are vital for organism growth and maintenance.
Mutant Isolation for
Read MoreCellular Dynamics: Adhesion, Signaling, and Cancer Biology
Cytoskeleton Structure and Function
Actin Microfilaments
Actin is the most abundant intracellular protein in eukaryotic cells. While some organisms may have only one gene, humans possess six actin genes that encode different isoforms. Four α-actin isoforms are present in various muscle cells, while β and γ actin isoforms are found in non-muscle cells. These isoforms differ by only 4-5 amino acids.
Actin exists as a monomer, G-actin (globular form), and a polymer, F-actin (filamentous form).