IGEM Bordeaux 2015


To avoid confusion about the terms "biosecurity", "biosafety" and "biohazard", some people gave a definition of each of these terms.

Biosafety describes principles, technologies and containment practices put in place to avoid accidents and unintentional exposure to pathogens and toxins.

Biosecurity describes the protection measures put in place and management of important biological materials in laboratories, in order to prevent them from being accessed without authorization.

Biohazard includes, in this case, both biosafety and biosecurity.

Reference :

The team who worked in the lab received instructions of lab safety with safety training. We learned how to act in the case of an accident, where to find emergency showers, fire extinguishers and emergency doors. Some basic safety requirements were discussed such as wearing gloves and a lab coat for most procedures. In some cases, during the use of ethidium bromide, nitrile gloves are mandatory. Other experiments must be conducted with safety glasses. It is also recommended to wear clothes offering a minimum of protection. We also learned about working with chemical products and how to dispose of them. Most products used are classified as non-hazardous (even for the sulfation protocol). Chemical products are just irritants and so need to be handled with gloves. In the lab, there is a specific solvent cabinet for liquid wastes. Moreover, all biological waste will be autoclaved before disposal. All work is done on benches or under open-front hoods.

Since we worked with non-toxic organisms as Escherichia coli (BL21) and Saccharomyces cerevisiae (Invsc1), all waste that has been in contact with bacteria was put to bacterial waste in aseptic conditions but no specific security procedures needed to be put in place.

Why is it safer to use Curdlan rather than copper sulfate ?

1. Copper Sufate

For the Environment Even if copper is essential for life at low doses, it is environmentally toxic at higher doses. Not being biodegradable, it spreads through rain water in soils and in river waters. It accumulates on the soils and vineyards are polluted. Its spread is facilitated by water and wind erosion. This element has been used many times to treat mildew which has resulted in it’s accumulation in the Aquitaine region.
This compound also modifies the biosphere since it is toxic for worms and microorganisms living in vineyard soils. Furthermore, copper sulfate does not distinguish harmful and beneficial fungi. It disrupts, for example, the development of mycorrhiza fungi that live in symbiosis with the plant’s root to help the access to nutrients from the soil to the vegetal. The microfungi that decompose the material to fertilize the soil are also in danger.
These effects are poorly seen on an area not exceeding the current authorized limit in organic farming (4 kg of copper per hectare per year, according to AFSSA (French Agency for Food Safety)). However, in terms of conventional agriculture, there is no limit for this substance. The measure reduces the damage to the biosphere but isn’t sufficient: copper sulfate is tolerated but not banished. It is therefore necessary to take more drastic measures by reducing the use of this substance.

For Humans Through the food chain, copper is an essential element for life at low doses. It is found in insects, fish, mammals and all herbivores, carnivores or omnivores. However, it is harmful if swallowed or inhaled, in cases of skin contact, eye contact (hence the compulsory wearing of gloves masks and glasses during our project) and is very toxic to aquatic organisms. We must not underestimate the long-term effects of chronic copper use.
Also, the copper-related risks are increased if added residues of this product from agricultural cultures, other food sources containing copper as tap water. Living near the wine places, like winemakers, are the most exposed.
Indeed, when it accumulates in the body, it is in too large quantities, it would affect the removal system of the beta-amyloid protein in the brain. This is harmful to the nervous system and is implicated in Alzheimer's disease. The protein, in excess in patients, is a peptide which is mainly aggregates (plaques) characteristics of the disease, and is present in soluble form in healthy patients.
In humans, it is known that copper occurs naturally and in normal amounts. It can protect neurons against oxidation. However, several studies have shown that copper plays a key role in neurodegenerative diseases like Alzheimer's. It is also increasingly referred to as an "environmental illness". Indeed, when it is accumulated in the body in large quantities, it is supposed to affect the removal system of the beta-amyloid protein in the brain. This is harmful to the nervous system and is implicated in Alzheimer's disease. The protein, in excess in patients, is a peptide which is mainly aggregates in the case of disease, and is present in soluble form in healthy patients.

2. Curdlan

Not dangerous for Humans Our project aims to use a polysaccharide which is synthetically produced by our genetically modified organisms. This molecule already exists in nature, it is naturally present in the yeast’s wall. No bad impact on the environment has been identified. Compared to copper sulfate which is a toxic compound, this molecule seems to be more environmentally friendly.
In 2013, the “Savoy ADAbio” tested on vine plants the effect of very low doses of different sugars in order to replace the copper treatment in the fight against pests. For example, they tested the effect of fructose against mildew. After different doses were tested, an encouraging result emerged : the weekly fructose application of 100 g / ha had a similar effect than a treatment of 600 g / ha of copper. According to this testimony, we now know that sugar helps fight against mildew.
Also used in many different applications, Curdlan doesn’t seems to have bad effects (see Other Effects Curdlan). However, we also collaborated with the Oxford iGEM team to test the toxicity of this molecule on the bacteria that already live in nature. This experience is useful to know the impact of Curdlan on other organisms. Another experience would have been interesting : a toxicity test on plant cells or animal cells. Unfortunately, we didn’t have the capacity to carry this test out in our laboratory. For now, we are still waiting for the results.
In food industry, the additive E424 (Curdlan) is used as a thickener, stabilizer, gelling and firming agent. This is reassuring because it is a common product in the food chain, and not reported as toxic.

We are not using the entire cell Another important theme is the spread of new organisms in nature. Indeed, this could alter biodiversity. If we want to directly use our synthetic organism on the plant, we must integrate death genes in their genomes to create organisms that are not be able to live in natural conditions. In the case of our project, we are not planning on directly applying our genetically engineered bacteria on the plant but only our purified molecule. In other words, we chose to spray on the vine only the cell product: Curdlan. In our project, the cell can’t evolve and in any manner alter the environment.

Effect on the plant