Mimicking insect communication: Release and detection of pheromone, biosynthesized by an alcohol acetyl transferase immobilized in a microreactor

Infochemical production, release and detection of (Z,E)-9,11-tetradecadienyl acetate, the major component of the pheromone of the moth Spodoptera littoralis is achieved in a novel microfluidic system, designed to mimic the final step of the pheromone biosynthesis by immobilized recombinant alcohol acetyl transferase. The microfluidic system is part of an "artificial gland", i.e. a chemoemitter that comprises a microreactor connected to a microevaporator and is able to produce and release a pre-defined amount of the major component of the pheromone from the corresponding (Z,E)-9,11-tetradecadienol.. Performance of the entire chemoemitter has been assessed in electrophysiological and behavioral experiments. Electroantennographic depolarizations of the pheromone produced by the chemoemitter were ca. 40% relative to that evoked by the synthetic pheromone. In a wind tunnel, the pheromone released from the evaporator elicited on males a similar attraction behaviour as 3 virgin females in most of the parameters considered.Peer reviewe

Multivalent Binding of Small Guest Molecules and Proteins to Molecular Printboards inside Microchannels

β-Cyclodextrin (β-CD) monolayers have been immobilized in microchannels. The host-guest interactions on the -CD monolayers inside the channels were comparable to the interactions on β-CD monolayers on planar surfaces, and a divalent fluorescent guest attached with a comparable binding strength. Proteins were attached to these monolayers inside microchannels in a selective manner by employing a strategy that uses streptavidin and orthogonal linker molecules. The design of the chip, which involved a large channel that splits into four smaller channels, allowed the channels to be addressed separately and led to the selective immobilization of antibodies. Experiments with labeled antibodies showed the selective immobilization of these antibodies in the separate channels. \u

Plot of reaction velocity of <i>Acinetobacter</i> wax synthase vs substrate (<i>(Z,E)</i>-9,11-tetradecadienol) concentration (1.25 µM–1.3 mM) giving in batch a Michaelis-Menten profile.

<p>Plot of reaction velocity of <i>Acinetobacter</i> wax synthase vs substrate (<i>(Z,E)</i>-9,11-tetradecadienol) concentration (1.25 µM–1.3 mM) giving in batch a Michaelis-Menten profile.</p

Drawing of the Silicon-glass microreactor with a section of the microchannel packed with NTA-functionalized agarose beads, with the dark grey box representing an infinitesimal volume <i>n</i>, together with the canonical enzymatic reaction, based on the Michaelis and Menten kinetics, adapted for substrate conversion with <i>atf</i>.

<p>Drawing of the Silicon-glass microreactor with a section of the microchannel packed with NTA-functionalized agarose beads, with the dark grey box representing an infinitesimal volume <i>n</i>, together with the canonical enzymatic reaction, based on the Michaelis and Menten kinetics, adapted for substrate conversion with <i>atf</i>.</p

Behavioral responses of <i>S. littoralis</i> males (N = 20 for each assay) to a 10 ng/µl aq. solution of the pheromone containing 4% DMSO released by the evaporator (evaporator pheromone); 3 virgin females; a filter paper containing 10 µg of the pheromone in hexane and to the blank.

<p>Same letters over bars corresponding to the same behavior are not significantly different (χ² test, P<0.05).</p

Mean percentage of the EAG response from 10 insect antennae to the blank and the pheromone released from the microreactors (“uRs”) relative to the response to 10 µg of synthetic pheromone.

<p>Mean percentage of the EAG response from 10 insect antennae to the blank and the pheromone released from the microreactors (“uRs”) relative to the response to 10 µg of synthetic pheromone.</p

Electroantennographic detection of the pheromone produced by two microreactors and emitted by the evaporator (center) <i>vs</i> response to a filter paper containing 10 µg of the synthetic pheromone (left) and blank (right).

<p>Electroantennographic detection of the pheromone produced by two microreactors and emitted by the evaporator (center) <i>vs</i> response to a filter paper containing 10 µg of the synthetic pheromone (left) and blank (right).</p