Old McDonald had a Colony of Bacteria

..Or is it a swarm of bacteria? A school? Pack?! Herd!?!

Whatever the group designation may be, the majority of bacteria used in research nowadays have been domesticated much like dogs were domesticated from wolves. In fact, bacteria may just hold the world record for “Most Recently Domesticated Living Organism”. Unlike their wild type brethren, laboratory strains of bacteria have lost their wild features that allow them to thrive in their normal habitats. Let us focus specifically on E. coli for the sake of simplicity.

You may have heard of E. coli from its association with food borne illnesses caused by eating tainted meat and produce. However, what you may not realize is that not all E. coli are bad. Surprisingly, E. coli are important players in the production of proteins such as enzymes in your laundry detergent. Thought your whites came out whiter because of that new washing machine? Think again! But how did E.coli  go from giving us diarrhea to cleaning our diarrhea-stained clothing? The answer is through domestication!

Domestication of bacteria: Parental bacteria found in the intestines. Subsequent passages grown on Petri plates.

E. coli was originally isolated from the jungles of the human intestine in 1885 by Theodor Escherich. Few studies were carried out on this bacteria until 1922 when wild type E. coli’s domesticated counterpart, E. coli strain K-12, was found in the stool sample of a diphtheria patient. A pure culture of this strain was maintained in the cushy labs of the prestigious Stanford University (Bachmann, 1972). Due to its comfortable living situation, E. coli K-12 soon lost many of the traits that enabled its wild counterparts to survive in the gut. Even pathogenic E. coli today, such as the notorious E. coli O157:H7, have the potential to become as harmless as the K-12 strain. With enough generations grown in a nurturing environment, harmful bacteria can afford to discard their defenses and are no longer a threat to humans. 

Multiple transactions later...
E. coli’s loss of disease causing potential became an opportunity for scientists to continue their research on this organism without much risk of exposure to an opportunistic pathogen. From this K-12 strain arose a multitude of E. coli strains, such as strain AG1 and strain MG1655, each one possessing a slightly different genetic profile. To date, a large number of lab strains of E. coli exist; each developed for a different research purpose and each one missing a combination of genes—termed knockouts—for the study of different metabolic pathways and/or reactions to various external stimuli.

Effects of external stimuli

Study of metabolic pathways

As scientific techniques became more advanced, researchers began to take advantage of the rapid replication times of E. coli and its genetic manipulability to synthesize proteins in a fast and cost effective way. Much like how dairy cows are bred to overproduce milk, strains of bacteria in biotechnology companies are genetically manipulated to churn out protein products such as insulin and enzymes to be added to laundry detergent, just to name a few.

Genetic manipulation of E. coli. P = Protein Product

So the next time you do a load of laundry, take a moment to thank the lowly E. coli, an often misunderstood bacterium that was plucked from the obscurity of the intestinal tract, domesticated on a Petri plate and turned into miniscule protein farms.

E-I, E-I, O.   


*Pictures are not drawn to scale; E. coli are not known to have faces