In 2012, we set out to establish a new analytical chemistry platform for the analysis of soil, crop, plant, leaf and insect samples with focus given to insecticides, toxin residuals, phosphates, odors, nutrients, lipid precursors and pheromone signals underlying sex-specific reproductive behaviors. Meanwhile, we set out to organize a communication and exchange platform for cooperation between China and France in the field of Agricultural Biotechnology, Applied Microbiology, Chemistry, Ecology and Environment Protection. For microbial formulation to be explored for mass-rearing of farm animals and mass production of beneficial microbial strains responsible for highly improving plant nutrition, plant protection and crop yield, main interests were given to the development of Bacillus bioproducts.
For insect control, key model studies addressed agricultural insect pests such as whiteflies and moths, but also dipteran fly and mosquito species vectors of human and cattle diseases (Haemetobia irritans, biting horn fly; Lucilia seracata, green bottle fly or sheep blowfly; Musca autumnalis, face fly; Aedes aegypti, yellow fever mosquito (vector Chikungunya, Dengue, Mayaro and ZIKA); Aedes vexans, inland floodwater mosquito (vector ZIKA); Anopheles arabiensis, African malaria mosquito (vector Malaria), Culex tarsalis, Western Encephalitis mosquito (vector Cache Valley Virus); Psorophora columbiae, riceland mosquito (vector equine encephalitis virus), among many others). Synanthropic ectoparasites such as L. seracata oviposit on the surface of fresh wound beef muscle. They lay eggs in and infect livestock (genus Ovis) like domestic sheep. Then the larvae can move and invade all living tissues from heart to lungs and liver, leading to myiasis disease. Like ticks, mosquitoes feed on blood and attack all-warm blooded vertebrates. Most of all mosquito species are rather opportunistic in their choice of host for blood meal. Some mosquito species show more consistent preferences for a specific animal, i.e. bird or mammal depending on the abundance of choice, or for human like in the case of Ae. aegypti.
However, food or host preferences can change very quickly. A difference in a single olfactory receptor is linked to the anthropophilic biting behavior of Aedes. It is not excluded that a single gene mutation and a multiplicity of choice in a farm managing both crop and animal diversity can soon shift host preferences from human to cattle and/or poultry. Therefore, every single cattle or breeding is a target for blood-sucking insects in search for a meal. Infestation of pests can lead to extensive blood loss to livestock, resulting in anemia and poor health conditions (lack of oxygen intake), severe exhaustion, weak reproduction rates, reduced productivity and even high levels of mortality in the herd.
Accordingly, numerous strategies have been employed to deal with insect species noxious to livestock. This begins by removing water sources, releasing bats, birds or dragonflies, introducing mosquito fish and/or largely spreading chemical insecticides (toxins, mineral oils, organophosphates, carbamates, pyrethrins, pyrethroids or IGRs, i.e. insect growth regulators). The problem comes out that cattle cannot survive without water, that bats are not domesticated animals, that birds do not specialize on insects, they also eat fruits, that dragonflies can eat also butterflies, that there are serious adverse assessments for the extensive use of Gambusia affinis as predator of mosquito larvae (negative impacts on native fauna, aquatic systems and bioversity), that insects have developed high resistance capacity to insecticides and that these chemicals are not so virtually non-toxic and/or not so relatively safe for cattle and human health. New insect control methods need to be envisioned for agricultural industry to reduce, minimize or eradicate risks to human health and the environment. Synthesis of new eco-drugs such as ORSA (Odorant Receptor Suppressing Agent) that aims at the inhibition of pheromone sensing in the target insect pest species is proposed as alternative to chemical insecticides (see Picimbon 2019: “Olfactory Concepts of Insect Control – Alternative to Insecticide, Springer Nature Switzerland AG). The ORSA plan for plant, cattle and human health is a multidisciplinary approach of insect pest control in a species-specific manner. It enrolls cooperation and expertise in different research fields from entomology, ethology of insect behavior, chemical ecology, pheromone chemistry, analytical chemistry, organic chemistry, molecular biology, biochemistry, electrophysiology and neurobiology of olfaction, i.e. innovation and tight joint collaboration where chemistry and biology combine in search for solutions to the insect problem worldwide. In ticks, flies, mosquitoes and any other types of pests, primary objectives are to identify age-, sex- and tissue-specific chemicals as a central part before to test behavioral and physiological importance of each candidate compound for insect pheromone (see Wang et al., 2019: Cartography of odor chemicals in the dengue vector mosquito, Sci. Rep. 9: 8510).
For consequences in an innovative sustainable pheromone-based technology for insect control, not only the behavioral importance of each identified compound, but also the molecular binding sites of OBP/olfactory receptors in the antennae needs to be investigated before to orientate ORSA synthesis.
Chemical identification is required to set up aggregation, oviposition or sex traps, i.e. pheromone lures. The specificity of each OBP/OR for target pheromone ligand is also such that new synthetic pheromone analogs can be designed and produced to completely block the activation of insect olfactory receptors in an irreversible manner (see Picimbon, 2002a,b, 2003a,b, 2005; Picimbon and Regnault-Roger 2008; Liu et al., 2019; see publications, conferences and concepts below). Cooperation has been initiated not only for Aedes mosquito pheromones, but also for male moth sex pheromones, aphrodisiac substances released by abdominal hairpencils during nuptial courtship to facilitate the acceptance of the male exposed to conspecific females as found for pyralid moths, i.e. European corn borer Ostrinia nubilalis (see CIFCA stipend 1996; ongoing collaboration with LABERCA, Nantes, Pays de Loire, France).
Fig. 1 China-France 2012 in Bàotū Quán (Jinan, Shandong): Agricultural Biotechnology, Chemistry and Environment Protection.
From left to right: Christian Cambillau (AFMB, Marseille), Jean-Pierre Renou (IRHS, Angers) , Florence Fouque (IPG, Guadeloupe), Ryszard Lobinski (IPREM, Pau), Bruno Lebizec (LABERCA, Nantes), Dominique Wolbert (ENSCR, Rennes), Paolo Pelosi (CAS, Beijing), our guide, Guoxia Liu (SAAS, Jinan, Insect Group). Host: Jean-François Picimbon, “Jeff”, Jie Fu 杰夫 (SAAS, QLUT, Jinan, Insect and Analytical Chemistry Groups)
Fig. 2 Institute of Quality Standard & Testing Technology for Agro-Products (Wang et al., Sci Rep. 2019)
Fig. 3 Agilent Innovation - Automated Workflow. High Resolution Gas Chromatography/Mass Spectrometry (GC/MS) platform
Fig. 4 Meat & Milk Industry - Bovine health protection - Control of dipteran species (green bottle fly) mediator of infectious diseases in cattle (myiasis)
Fig. 5 Typical Total Ion Chromatogram (TIC) of adult Aedes aegypti mosquitoes. Different signatures characterized by significant age-related variations in females (atop) and males (below). The red square shows a specific chemical signature in old adult female dengue vector mosquitoes (Wang et al., 2019)
Fig. 6 Concept of Odorant Receptor Suppressing Agent (ORSA). A synthetic compound (organic chemistry) that contains additional branch derivative of the natural pheromone is produced to target specific binding sites in odor binding protein-odorant receptor supra-molecular complex, resulting in free but anosmic insect pest species (Picimbon, 2002a,b, 2003a,b, 2005, Picimbon and Regnault-Roger 2008, Liu et al., 2019)