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Accueil > Équipes > Trafic et signalisation membranaires chez les bactéries > Sécrétion et facteurs de virulence

and now...

EPI-Cuticle

or the story of bugs-in-a-bug (bacteria in an insect)

EPI-Cuticle

The EPI-Cuticle group-project is a biomimicry-based multidisciplinary project on insect cuticle. It started early 2016 and comprises people from two labs on the LyonTech Campus : MAP UMR5240 (Microbiology) and IMP UMR5223 (Polymers). We are welcoming other people, maybe from mechanics, or materials sciences, in the near future.
More specifically (see below), we are interested in insect mouth-parts.

You may therefore call us the first insect dentists ever...

EPI-Cuticle group-project (Biomimicry)

EPI stands for Interdisciplinary group-project (french Equipe-Projet Interdisciplinaire), and is meant to gather, in a single environment, researchers from different laboratories and disciplines, willing to work together on a single biological object (in our case the insect cuticle).

Insect cuticle is a biological polymer assemblage/ alloy composed of four biochemical compartments : the first two, chitin and cuticular proteins, are the core-polymeric objects of our projects. The third important part of the biomaterial is its biological glu-component, comprising the aromatic-based cross-linking material of the insect cuticle (the so-called sclerotizing component). Finally, lipids and lipid impregnation of the material is the final assembly part, but will not be considered in our project. It has important consequences in both the water-barrier behavior and the volatile-based chemical ecology of the insect cuticle, but such properties are studied by other groups and projects.

Insect cuticle is one part / example of the exoskeleton solution adopted by evolutionary successful animal classes within the arthropods, and challenging the endoskeleton-based solution of the vertebrate sub-phylum (based on different types of solid materials, such as bone -for the skeleton-, and dentine or enamel -for the mouth-parts-).

Xylella fastidiosa
Xylella fastidiosa
µ-localised biofilm of the bacterial species Xylella fastidiosa in its plant hopper’s mouth
© Almeida group, Berkeley University

As for the other biological solids, insect cuticle bears different peculiarities and functions that deserve specific scientific attention : their biogenesis (development), their morpho-mechanical properties (biomechanics), and their biological adhesion properties. Being externally exposed, the latter property is especially important for the communication/barrier properties of the arthropod individual with its environment, including its microbial environment.

As for the vertebrate tooth system, the solid cuticle of insect mouth-parts is often hyper-specialized into both extraordinary bio-materials and exceptional biological objects : the butterfly spiral trumps, the fly pads, the coleopteran jaws or the diverse (evolutionary independent) sucking mouth-parts of many insect orders (mosquitoes, plant bugs, lice, fleas etc…) are just examples of an impressive diversity.

In this context, our biological object model of insect cuticle is that of the hemipteran (plant bug) mouthparts, particularly the four internal parts of the Hemipteran stylet, and more specifically that of the aphid stylet. The biomimetic object is that of a biosyringe, that bears both very peculiar mechanical properties (micro-drilling machine) and biological adhesion properties (microbial filter).

If ever you were not convinced that insect cuticle, and its mouthparts avatars, can do extraordinary things, take a look below...

Panorpe
Panorpe
Panorpa observé en microscopie électronique à balayage (MEB).
© Stephan BORENSZTAJN/CNRS Photothèque (20120001_1404)
Fourmi licorne
Fourmi licorne
Vue ventrale d’un fossile de fourmi-licorne, “Certaomyrmex ellenbergeri“, préservé dans de l’ambre crétacé en Birmanie. Les fourmis sont les insectes sociaux les plus nombreux de notre écosystème. Certaines d’entre elles sont d’importantes prédatrices et chassent en solitaire. Les fourmis Ceratomyrmex de plus de 99 millions d’années seraient les précurseurs de la lignée actuelle. Ces fourmis primitives possédaient des mandibules en forme de faucille leur servant de piège et une corne frontale qui leur permettait d’écraser, d’empaler et de transporter des proies de grande taille telles que des myriapodes. Cette morphologie extrême suggère une adaptation pour la prédation en solitaire de larges proies, une écologie étonnamment sophistiquée pour cette fourmi parmi les plus anciennes connues.
© Vincent PERRICHOT/Géosciences Rennes/CNRS Photothèque (20160064_0002)
Fourmi legionnaire
Fourmi legionnaire
Colonie de fourmis légionnaires dites aussi fourmis nomades, au Cameroun. Ces fourmis se déplacent régulièrement, d’où leur nom. La colonne de déplacement est protégée par des soldats aux mandibules impressionnantes.
© Rumsaïs BLATRIX/CEFE/CNRS Photothèque (20140001_2400)

Voir en ligne : Go to Bio-inspiration Group (BiG) of INSA de Lyon