Molecular recognition in insect olfaction / Recording from single olfactory neurons in insects

The background to our presentations is that I was friendly with Marshall Stoneham and yet I and an insect olfaction expert at the Max Planck Gesellschaft, Bill Hansson, failed to test, before his premature demise, some ideas that Marshall was developing following on from his interactions with Luca Turin. However, with my new colleague, Wynand, we now feel that it would be timely to look again at olfaction and any quantum biological associations using insect olfaction as a much more tractable and quantitatively measurable modality than human olfaction. Today we could then take forward the specific prospect of our doing some initial hypothesis testing via insect olfaction. I, as a chemist, will introduce the subject of how we engage with insect olfaction to identify olfactory ligands. I will describe some of the properties of the molecular recognition process involved in which we mostly see high selectivity for specific molecular structures rather than the recognition of functional groups and homologous series. A crucial aspect of the experimental results leading to this this observation is that realistic stimulus concentrations need to be applied rather than high concentrations or even neat samples of olfactory ligands previously used. The observation is currently difficult to explain by the molecular mechanisms of olfaction so far elucidated. After Wynand has described these mechanisms in further detail and offered some advanced investigative methodology we would like to invite wider discussion from physicists and biologists on new experiments, for example with isotopic labelling of ligands for single olfactory neuron response measurements.

Many insects use their senses of smell and taste to locate and select the hosts from which they feed, and to find sites for laying eggs. Smell and taste also play important roles in mate choice and other social interactions. The sense of smell in insects is mediated by bipolar sensory neurons (the olfactory receptor neurons, ORNs) located in structures called sensilla. In Drosophila, as in many other insects, these sensilla are found in the antennae and maxillary palps. We will briefly examine the