Team:Aix-Marseille/Description

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Description

Our focus this year is fighting bed bugs, worldwide invasive pests, that are invading homes and biting humans for their blood. These tiny bugs became harmful from the moment humans made caves their homes, as the original hosts of bed bugs were bats. Nowadays humans don’t live in caves, but this temporary troglodyte dwelling came with a cost: fighting against an insect addicted to human blood. While their bite usually doesn’t transmit any disease, it still induces serious dermatological and allergy issues.

The breaking bugs project aims to provide a human-friendly, and efficient solution to eliminate bed bugs. The plan is to elaborate an attractive lethal trap. We will use biosynthesized pheromones as a chemical lure to attract the bugs into the trap and infect them with Beauveria bassiana (an entomopathogenic fungus), causing a fatal epidemic among the sheltered colonies.

The problem ?

An alternative weaponry must be found to replace the harmful and expensive traditional insecticides, that is now nearly useless against bed bugs. Because of the excessive use of insecticides, the tiny bugs developed multiple resistance mechanisms (exoskeleton thickening and enhanced metabolic pathways to neutralize toxic chemicals). As a result, pest control companies are obliged to increase the insecticides' doses.

The plan ?

First subunit

To elaborate our trap, we are going to use the biological properties of an entomopathogenic fungus called Beauveria bassiana. It was first used as a way to fight against insects in agriculture in Canada, and later on, all over the world. The fungus can penetrate bed bug's exoskeleton: the cuticle. Firstly, the spore attaches to the cuticle and germs. Secondly, the spore breaks down a first fatty acids layer using the lipase protein. The fungus keeps going and breaks the second layer: the chitin, using the endochitinase protein. Afterward, it reaches the insect's hemolymph, then feeds, multiplies, and releases toxins, causing the bugs death. The whole process takes about 12 days. Our objective is to enhance the fungus to improve its killing efficiency and speed by overexpressing the lipase and endochitinase proteins, and adding other adjuvants.. We want to reduce the lethal doses and kill the bed bugs in fewer days.

The use of pesticides, such as chlorpyrifos is authorized in the European Union in any knowledge of the very numerous risks of toxicity incurred for the consumers of products of vegetable origin, by adding more the risks for mammals, birds, aquatic animals, and bees. Moreover, researchers are trying to find an eco-friendly and natural method to fight bed bugs. Thus, using Beauveria bassiana side to side with pheromones is one highly biological fight method.

The fungus can easily penetrate bed bug's exoskeleton: the cuticle. Once inside the insect's hemolymph, the fungus feeds and multiplies, causing its death. Our objective is to enhance the fungus so that it is highly virulent for bed bugs. We want to reduce the lethal doses and break the bugs. Furthermore, the excessive use of insecticides thickened the bed bug's cuticle. As a result, pest control companies are obliged to increase the insecticides' doses.

The pheromones that we plan to use, are chemical molecules produced by the bugs. They use them to navigate and find their shelters. The plan is to add biosynthesis pathways in E. coli two produce two types of pheromones: benzyl alcohol and DMDS/DMTS.

Inspiration

We used some papers to elaborate our plan