Team:Toulouse/ethics

The ethical questioning turned out to be one of the major starting points of our project. Acting on an established environment and modifying it is no mean feat and our thinking combines technical and philosophical point of views. The actual purpose of our project also leads us to undertake an ethical questioning about the role of the scientist regarding “useless” things such as the trees lining the Canal du Midi.

Protection of the beauty

Is it the scientists’ role to protect beauty?

Beauty is a feeling of satisfaction and is selfless. It is more a feeling than the property of a thing, this is not a notion we can clearly understand. Indeed, we can find something beautiful even when we don’t know the purpose of the object. There is always a distinction between natural beauty and artistic beauty according to Hegel, the famous author. The artistic beauty is born from our mind and our spirit: it is an element of signification of the work of art whereas the natural beauty of the object is external. In a way, the Canal du Midi combines both types of beauty: a natural one regarding the nature, the centenary plane trees but also an artistic one since the Canal was built by the human hands. Usually, scientists judge beauty as a superficial feature not deserving to undertake any kind of scientific efforts to maintain it. The traditional role of scientists is to solve global issues and to elaborate complex strategies in order to find useful solutions for everyone’s life. Once made this observation, one may wonder why synthetic biology would be used only to protect the useless beauty of a local heritage such as the trees lining the Canal du Midi.

This crucial interrogation leads us to consider science and synthetic biology in another way. What if the role of scientists was also to make people rediscovering the beauty of nature? What if the bases of new scientific challenges resulted from a more local scale? Science does not have to be elitist, it has so much to gain opening itself to these challenges. First scientifically, as research is never useless and as we never know the impact and the scope of our results. Then, socially as we could measure the deep interest raised by our project within the population and the media. Adopting a new vision of synthetic biology, we probably make people change their mind about this innovative discipline. The traditional cold objectivity of science distances itself from the society. Scientists are also beings capable of feeling the beauty, sensitive to the charm of landscapes and able to understand the usefulness of useless trees … The design of a strategy to protect useless beauty may seem senseless but we believe that it is also the scientist’s duty. Thus, it becomes essential to protect the beauty of this site.

Human intervention in the nature

Our main questioning aim to understand the complicated relationship between man and nature. Does the mankind have the proper right to operate in nature? Is modified nature considered as artificial?

Mankind & Nature

Nature is known as a creation of God. Human is linked to the nature and for that reason the nature deserves to be respected and loved. Mankind has always been linked to Nature as its survival depends on what comes out of the ground, the trees, the oceans… The nature is a source of wealth for the humankind. It ensures survival and development by giving men the wood, the rocks, the soil to build shelters. Being in contact with nature can allow men to feel strong emotion, as describe by poets like Hugo and Lamartine

Since the birth of humanity, man himself understood well the importance of studying and mastering Nature to develop the civilization. Still today the most advanced technologies often try to mimic natural phenomena. With the development of the civilizations, men modified their environment, changing it for their own comfort depending on their own desire. By increasing their cities and acitvities, humans modify the natural environment. With the industrialization of the societies, the natural environment has suffered from human activities such as waste discharges, oil slicks, intensive fishing but also the introduction of devastating species such as the pathogen, Ceratocystis platani. However, despite these negative aspects, men are capable of favorable actions to help the environment and fix their mistakes. The current trend is to limit the impact of human interventions on the nature, and hopefully this trend is not transient and will not vanish. A new desire is born, a wish to protect the nature and the wildness. Man fits with his position: he takes advantage of the environment and the environment takes advantage of the reasoned human interventions. There is an adaptation of the mankind toward the nature. Moreover, humans have the capacity of empathy: people are able to understand the emotions and cognitive states of other organisms and to identify to them. To respond to these feelings, humans have technological tools allowing them to fight against enemies such as Ceratocystis platani.

Nature and artifice

Talking about the nature refers to the whole world with an exception: all the transformations made by mankind. Thus, the nature consists in the real without all the artificial elements created by humans. The nature is existing regardless of men and his interventions whereas artificial is everything that exists thanks to humans.

However, pretending that natural and artificial are opposite does not seem to be true. Man cannot create without elements provided by the nature, he is just transforming the nature, changing the shape. Thus we may wonder if there is a true difference between natural and artificial. The border between these two notions is not as obvious as it seems. The landscapes are shaped by the hand of man, animals are domesticated, and now bacteria are considered as cell factories. A natural reserve is artificially preserved as the result of human actions. Is there still something natural since the birth of humankind? Actually, the artifice is a slight modification of Nature and couldn’t exist by itself. The distinction between natural and artificial seems sterile and we clearly understand that these notions are inextricably linked and need each other to exist.

Back to our project

These inextricable links are obviously the basis of our project. We aim to artificially preserve a natural heritage shaped by Pierre Paul Riquet hundreds years ago. The modification of a naturally occurring form of life to strengthen it is maybe just the imitation of the natural evolution process. What is considered today as ‘non-natural’ may be one day regarded differently. To the extent that everything is done not to unbalance the ecosystem, our intervention can be judged rightful, even more than the use of chemicals.

SubtiTree. Cette partie n'irait pas plutot dans "spreading"?

SubtiTree will live in sap tree, thus we use one endophyte Bacillus subtilis strain. In order to contain our bacteria in this area during a short period of time, we modified some of its survival characteristics. First of all, the control of synthetic bacterium location concerned us,that is why we border it inside the plane tree. Sap tree is known to contain a certain quantity of proline which could allow bacterial growth whereas the soil is composed by only trace of this amino acid. Thus, we decided to delete the proline production pathway to make an auxotrophic bacterium for this amino acid.

Secondly, SubtiTree is conceived as an annual bacterium to avoid any kind of mutations. It is known that endophyte bacteria must sporulate to survive to winter. Thus, we chose a B.subtilis strain without late genes of sporulation. So SubtiTree is a non-sporing bacterium, which means that under stress conditions (cold temperature, food lack …) or outside the sap, the bacterium will not resist and die.

These two characteristics of SubtiTree show that it is an annual bacterium, which can only grow in sap tree. By combinind them, they prevent any long term colonization of an ecological niche by SubtiTree against wild type bacteria. These prevent a long term effect.

While we were trying to respond to bacterial spreading problem, at the same time we wondered about horizontal gene transfer. The transmission of genes from our synthetic bacterium to wild type bacteria could be blocked with two modifications. First, as used in genetic engineering, plasmids are a tremendous way to transfer some genic information. In this way, it is not the best way to restrict the collecting transgenic DNA. That is why we inserted our genes in the bacterium chromosome.

Secondly, some bacteria are able to accept chromosomal DNA, like Bacillus subtilis. Thus, the previous strategy is not efficient enough to prevent transfer. We could include the toxin/anti-toxin system. The toxin gene is near our synthetic gene, contrary to the anti-toxin gene. So if there is a transfer of our synthetic gene, the toxin gene will be included in the transfer. Receiver bacteria will die by the production of the toxic protein.

Our synthetic genes are not the only problem in the design of SubtiTree. One of the side effects of our cloning method is the persistence of antibiotic resistance genes. This is incompatible with the introduction of SubtiTree in the environment. It is possible to delete this resistance in chromosome. To conclude, the spreading limitation shown previously makes the use of SubtiTree acceptable in the environment.

Public perception

Thanks to the bolts we used in SubtiTree construction, its application interest civil services. Indeed some city halls and regional councils supported our local engagement. Beyond that, our project interests the highest level of the “Canal du Midi” administration: the national navigation authority and the Ministry of agriculture funded this project. They are still interested in continuing this work after the iGEM competition.

This project also received the attention of the public through several articles in newspapers, television, radio and internet. First we had just a local coverage, but days after days there were some national media coming to us. This coverage media allowed us to have contact with regular people and thanks to that they participated in the development of this project. This interaction with the public allowed us to develop the safety matter of our project. The support they gave us is the result of the scientific popularization of our project.

One single tree infected by the canker, that is a perimeter of a couple of hundred meters which is included in the prophylactic cut. So there a healthy population in this area, we want to protect this tree. There is a common principle in agronomics that said that you prefer to save the population to the subject. According to this concept the introduction of our GEM seems acceptable. A result of the subtitree’s introduction is the modification of endophytic microbial fauna, but without any treatment organisation of the entire population will be messier. As subtitree is an annual bacterium, its side effect will not last in the time, this disruption in this balance will return to the normal.

Furthermore, usual fungicides used come from chemical industry. They contain chlorine atom and aromatic hydrocarbon, so their remediation is complicated and they represent a source of pollution. We propose to use in this project biofungicide, so they are eco-friendly and more specific. Thus they seem to be a good way to fight against the fungal infection.

Feasability

We wonder about the feasibility of tree’s treatment. As we used endophytic bacteria, we can count on the natural growth of SubtiTree inside the sap. So we can inject few bacteria to be sure to have enough bacteria to protect the tree. Some researchers already inject bacillus subtilis strain in plants and observe an increase of bacteria concentration to a maximum of 105 bacteria/mL.

As we inject a poor quantity of bacteria, the injection remains cheaper than the injection of several litter of fungicide. Plus this injection prevents the cutting of trees, which is very expensive. Cutting one tree cost around 3 K€. The administration in charge of the protection of the “Canal du Midi” already plans to spend 220 million euros to cut and replant all trees along the Canal. Besides the important cost of cutting tree, it will destroy one of the symbols of south-west of France.

We know that SubtiTree could be improve in many ways, but in the iGEM’s circumstances we could not have the time to go deeper. First, we can improve the fixation module. Using chitin as fixation anchor is simple but not enough specific to fix just one fungus type. That’s why we first think to fix SubtiTree to one protein included in the Ceratocystis platani’s membrane: CP.