Team:Toulouse/project/strat
Strategy
Content
An ounce of prevention is worth a pound of cure
If you read about varroa here you learned the
influence of the mite in bee population decline,
and you probably realised that our project fits
into the fight against varroa.
Furthermore, current chemical treatments used to fight varroa
are not satisfying since they are harmful for bees and
human health, and beekeepers relate a lack of effectiveness.
Our project, ApiColi, is an alternative solution in the fight against varroa in order to establish balance between Apis mellifera and Varroa destructor and thus contribute to the preservation of ecosystems.
Introducing ApiColi
Our strategy is based on the alternate production of two molecules according to a circadian cycle, and thanks to a genetically modified Escherichia coli strain.
During the day, while bees are entering or exiting the beehive, butyrate is biosynthesized by our strain, ApiColi, in order to attract the varroa which is fixed on bees.
By night, ApiColi produces formate, a well-known molecule lethal to the varroa attracted during the day.
Formic acid is currently used to fight varroa but at very high doses that also have an impact on bees.
Figure 1: Circadian rhythm switch strategy
It’s a TrapiColi!
In our project, the engineered bacteria ApiColi will be placed at the bottom of a trap, called TrApiColi, positioned at the entrance of the hive. Varroas will be attracted and killed there, leaving the bee colony less exposed to both chemicals, and particularly formic acid.
Furthermore, at the moment, beehives are only treated with formic acid during spring and fall, when no
honey is being made. This is due to the fact that formic acid weakens bees but also that when varroa have entered the
brood, they are not affected by it.
The attraction power of ApiColi will enable us to prevent most varroas from entering the beehive and reaching the brood.
This way, our treatment would be useable even during the summer.
Apicoli circadian rythm
The synthetic regulation system used in ApiColi is based on a chimeric red light receptor that makes our bacterium sensible to daylight.
During the day
Formate expression is repressed and butyrate synthesis inhibition is stopped.
Thus Apicoli produces only butyrate.
During the night
The system reverses, and formate is synthesized while butyrate synthesis is inhibited.
References
- [1] Yves Le Conte, Marion Ellis, Wolfgang RITTER. Varroa mites and honey bee health: can Varroa explain part of the colony losses? Apidologie, Springer Verlag (Germany), 2010, 41 (3), <10.1051/apido/2010017>.
- [2] Sammataro, D., Gerson, U., Needham, G., 2000. Parasitic mites of honey bees life history implications and impact. Annual Review of Entomology 45, 519-548
- [3] Peng, Y-S., Fang, Y., Xu, S., Ge, L., 1987. The resistance mechanism of the Asian honey bee, Apis cerana Fabr., to an ectoparasitic mite, Varroa jacobsoni Oudemans. Journal of invertebrate pathology 49, 54-60.
- [4] S, L, P Wendling. 2012. Varroa destructor (ANDERSON ET TRUEMAN, 2000), UN ACARIEN ECTOPARASITE DE L’ABEILLE DOMESTIQUE Apis mellifera LINNAEUS, 1758. REVUE BIBLIOGRAPHIQUE ET CONTRIBUTION À L’ÉTUDE DE SA REPRODUCTION.
