Team:CIDEB-UANL Mexico/safety interview

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Overview

IGEM CIDEB 2014 considers biosafety as important as every other points of the iGEM competition. Because of this reason, the team decided to perform a Safety Risk Assessment focused on the project and in the lab practices needed to accomplish it. In this assessment, a description of our host organism is made, along with the genetic modifications that were applied to it, including preventive measures to avoid its dissemination and appropriate identification and containment measures, in the case it was released into the environment. Also the overall potential risks of the project were included, taking in consideration all of the possible risks of working in our laboratory, along with preventive measures to reduce risk to a minimum.

Organism's description

Escherichia coli (E. coli) is a large and diverse genus of bacteria belonging to the Enterobacteriaceae. Although most strains of E. coli are relatively harmless, some can potentially affect humans and animals. Pathogenic kinds of E. coli can cause diarrhea, along with urinary tract infections, respiratory illness and pneumonia, among other symptoms. E. coli can be commonly found in the digestive tract of humans and many animals. It plays an important role in the decomposition and absorption of certain nutrients in the intestine that the body cannot break down by itself and to also prevent the digestive track to be colonized by other harmful bacteria.

E. coli are capable of both aerobic and anaerobic cellular respiration, which is a characteristic that allows them to live in both oxygen rich and oxygen poor environments, which has allowed them to thrive in a wide variety of ecosystems.

As a prokaryote, E. coli bacterium has no organelles, and its genetic information is not enclosed in a nucleus. E. coli protective layer consists on a cell wall and a capsule that protects it from the outside, potentially harmful environment. E. coli goes through binary fusion on a regular basis if given the right conditions, usually at 37° Celsius, and it is able to thrive and reproduce at a very fast rate.

As previously mentioned, E. coli is one of the most diverse genera of bacteria, probably due to its adaptive abilities. Although there is a wide variety of different E. coli strains to choose from, not all of them have the same characteristics; some of them are pathogenic and are not safe to work with, which is the main reason why during the practices at the team’s laboratory, the E. coli’s strain that was used is the K12 DH5-α strain, which is one of the safest strains to work with, and one of the most used in biotechnology research. The K12 DH5-α strain is characterized by its poor abilities to colonize plant and animal tissue, and a low resistance to outside-lab environment, temperature fluctuation and different media composition causing the organism to die.

E. coli’s K12 DH5-α inability to colonize intestinal tissue was experimented in 1978 in a work made by R. Curtiss “Biological containment and cloning vector transmissibility” showing that the K12 DH5-α strain is not likely to behave as a pathogen in mammal tissue. Due to these previous mentioned characteristics, it is classified as a Class 1 Containment under the European Federation of Biotechnology guidelines, and according to the United States Environmental Control Agency (EPA) E. coli K12 DH5-α strain opposes a very low risk for other organisms and under contained conditions of fermentation and are safe to work with.

Genetic modifications

In order to accomplish the iGEM CIDEB 2014 project’s objective, E. coli went through some genetic modifications. The E. CARU project is divided into four different modules, each one of them adding a different characteristic to the bacterium. The four modules are:

1. Resistance

2. Capture

3. Aroma

4. Union