Team:Aix-Marseille/Description
Description
Our focus is fighting bed bugs, invasive pests distributed worldwide, that are invading homes and biting humans for their blood. These tiny bugs became harmful from the moment humans made their homes in caves, 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 allergic problems.
The breaking bugs project aims to provide a human-friendly, and efficient solution to eliminate bed bugs. The plan is to elaborate an attractive but lethal trap. We will use biologically synthesized pheromones as a chemical lure to attract the bugs into the trap and infect them with Beauveria bassiana (an entomopathogenic fungus). Then, the infected bugs return to their partners, causing a fatal epidemic even in hard to reach and hidden colonies.
The problem ?
An alternative weaponry must be found to replace the harmful and expensive insecticides, that are 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 such as chlorpyrifos). As a result, pest control companies are obliged to increase the insecticide doses with high risks of toxicity for mammals, birds, aquatic animals, and bees.
The solution : A two-part lethal trap
First part
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 the bed bug's exoskeleton: the cuticle. Firstly, the spore attaches to the cuticle and germinates. Secondly, the spore breaks down a first fatty acids layer using an enzyme: the lipase protein. The fungus keeps going and breaks the second layer: the chitin, using the endochitinase enzyme. Afterward, it reaches the insect's hemolymph, then feeds, multiplies, and releases toxins, causing the bed bug's death . The whole process takes about 10 days. Our objective is to aid the fungus to increase its killing speed by adding the lipase and endochitinase proteins and other adjuvants to the attractive trap. We want to reduce the lethal doses (LD50) and kill the bed bugs faster. We aim to produce the different enzymes in E. coli and have them secreted into the media.
Second part
Bed bugs produce a specific set of chemical substances called pheromones. They serve as a stimulus to navigate in space and create a path between their preys and their shelters. The plan is to disrupt this path and create a diversion using pheromones that can be found in the bed bugs' feces and exuviae including: benzyl alcohol and DMDS/DMTS. We are going to add the various biosynthetic pathways to an E. coli chassis, this procedure will enable the low-cost production of pheromones using simple substrates (Sugar...) to load the trap.