Escherichia colias an Experimental Organism

Abstract

Escherichia coli , a gram‐negative gamma proteobacterium, is presently the best‐understood organism. It is a paradigm organism in bacterial physiology and genetics as well as a key tool in molecular genetics in that many genetic manipulations throughout biology involve E. coli . Molecular cloning into one of many E. coli vector plasmids is a standard procedure in most molecular biology and biotechnology laboratories. E. coli is also the workhorse of recombinant protein production since conditions have been found that allow proteins from across biology to be efficiently expressed in and purified from E. coli . Indeed, the bulk of x‐ray crystal structures are performed on proteins that were produced in this bacterium. Finally, a collection of mutant E. coli strains each deleted for a gene nonessential for growth in a rich medium provides a resource to test the functions of genes from other organisms by assaying their ability to replace the function of an E. coli gene. Key Concepts: E. coli is a preferred host for gene cloning due to the high efficiency of introduction of DNA molecules into cells. E. coli is a preferred host for protein production due to its rapid growth and the ability to express proteins at very high levels. Bacterial conjugation can be used to transfer large DNA fragments from one bacterium to another. E. coli is a preferred host for the study of phage biology due to the detailed knowledge of its nucleic acid and protein biosynthetic pathways. The ability of E. coli to grow on chemically defined media coupled with its extensive genetic toolbox make it a key system in study of bacterial metabolic pathways.

Microbial β-Glucosidases: Screening, Characterization, Cloning and Applications

“…Bacterial β-glucosidase genes has been cloned from number of species and expressed in E. coli because of its high growth rate, easy handling, genetic simplicity, easy transformation and plasmid uptake, and it can grow to high cell density 200 g/1 [194,195]. However, expression in E. coli has several drawbacks such as formation of inclusion bodies, low secretion efficiency, absence of splicing machinery and inability to perform post-translational modifications such as glycosylation explaining why it is not successfully being used for expression of fungal β-glucosidase enzymes [196,197,198].…”

Solar light induced antibacterial performance of TiO2 crystallized glass ceramics

“…Study of optical density (OD) measurement of E. coli cell suspension confirms a systematic E. coli inactivation and decrease in E. coli cell suspension with time for crystallized glass under 2 hours light illumination. On the other hand, the test tube without any glass sample only with the bare suspension of E. coli cell shows an increase in optical density of E. coli cells in agreement with the sigmoid curve that is, a lag phase(static growth) followed by log phase (exponential growth) . After a two‐hour irradiation under sunlight, both the test tubes were placed for 24 hours incubation at 37°C.…”

“…On the other hand, the test tube without any glass sample only with the bare suspension of E. coli cell shows an increase in optical density of E. coli cells in agreement with the sigmoid curve that is, a lag phase(static growth) followed by log phase (exponential growth). 45 After a two-hour irradiation under sunlight, both the test tubes were placed for 24 hours incubation at 37°C. After incubation, the tube that contains only bacterial environment turn into hazy/cloudy in appearance while no turbidity is noticed in the test tube containing crystallized glass immersed in the bacterial environment ( Figure 2D).…”

Bacterial Genetic Engineering by Means of Recombineering for Reverse Genetics

“…Particularly, the use of phage recombineering proteins to perform recombineering was proven to be a highly efficient method to modify not only bacterial chromosomes, but also other replicons such as bacterial artificial chromosomes (BACs), which are frequently used to accommodate large inserts [up to several hundred kilo base pairs (kbp)]. In particular, Escherichia coli ( E. coli ) and Salmonella enterica ( S. enterica ) have extensively been used as workhorses for the implementation and development of different DNA-based recombineering technologies ( Cronan, 2014 ). While recombineering strategies will be the main focus of this review, bacterial gene replacements historically involved allelic exchange methodologies, and thus will also be briefly discussed.…”