Chemical attraction? (re-post)

August 12, 2010

The chicken or egg blog family is on holiday in Germany during August, so I probably won’t have a chance to write any new posts.  To keep you all entertained, I’ll be re-posting some of my earlier (pre-Sciblogs) articles.  This one is the very first post I wrote for this blog, from March 2009.

Research published in last month’s Chemistry and Biodiversity journal heralded the discovery of a new compound “tuataric acid”. Yes, isolated from our very own tuatara.

Stefan Schulz and his colleagues at University of Braunschweig, and collaborator Paul Weldon at the Smithsonian Institution, have analysed the constituents of the cloacal secretions in tuatara and found an unexpectedly diverse array of compounds. As tuatara have no external sexual organs, the cloaca is the “one stop shop” opening at their posterior end, with prominent skin glands on either side of the opening that secrete a greasy white substance. When the tuatara secretions were analysed, Schulz and colleagues found over 150 different types of glyceride-based molecules, including one never-before seen compound, which they dubbed “tuataric acid”.
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Foot odour, anyone?

November 4, 2009

If you’re passing by Karangahape Road in Auckland over the next 3 weeks check out the Crossing Wires Lab, a science meets art installation.  Plant and Food olfactory scientist Richard Newcomb and sensory artist Raewyn Turner have joined forces to produce this exhibition-come-science lab where the general public have the opportunity to participate in an active science experiment.

During the exhibition Newcomb and his team will be extracting odours from worn socks, supplied by a scientists, artists and joggers, and then offering the public the opportunity to categorise these odours (presumably in an artistic way, rather than an ew-foot-odour kind of way).  The installation features a science laboratory set up in the shop-front window where the odour extraction will take place, as well as performance exhibition art with interactive video imaging and audio. 

This exhibition/experiment runs from Nov 2nd to 20th and is funded by the Smash Palace funding initiative set up by Creative New Zealand and MoRST to encourage collaborations between scientists and artists.  Check out their blog for regular updates, video and audio clips.

Sniffing out disease

June 4, 2009

We all know that other mammals have a far more finely tuned sense of smell than we humans do.  In fact, the olfactory abilities of mice even extend to being able to identify individuals infected with parasites.  Now the discovery of a new class of olfactory receptors, reported in Nature last week, has provided an insight into what underlies this ability. 

The mammalian olfactory system comprises two major divisions: the main olfactory system, which deals mainly with environmental odours, and the vomeronasal organ, which plays a role in detecting pheromones.  The mammalian capacity to distinguish between a huge array of odours lies with the fact that individual sensory neurons in the olfactory system express only a single type of receptor protein on their surface. Each of these receptor types is tuned to a specific type of odorant and transmits signals to a specific part of the brain.  Until now only 4 major types of receptor were known: odorant and trace-amine associated receptors, mostly expressed in the main olfactory system, and vomeronasal type 1 and type 2 receptors expressed in the vomeronasal organ.  All these receptor types are members of the G-protein-coupled receptor (GPCR) superfamily, which initiate signalling pathways within chemosensory cells. 

Riviere and colleagues at the University of Geneva screened mouse vomeronasal tissue for new types of GPCRs and discovered that some sensory neurons express a class of protein known as formyl peptide receptors (FPRs).  FPRs were previously known to be expressed in the immune system where they have a role in mediating cellular responses to disease, inflammation and cell damage.  Riviere and colleagues found that the FPRs expressed in the vomeronasal tissue respond to the same activators that stimulate the immune system FPRs – that is, peptides and lipids derived from bacteria or associated with inflammation.  Five different types of FPR were found in the vomeronasal tissue.  In keeping with other types of olfactory receptor, each FPR responds to a distinct, but overlapping array of compounds and individual vomeronasal sensory neurons expressing FPRs do not express any other types of olfactory receptor. 

Although the role of FPRs has yet to be confirmed by behavioural studies, this report provides compelling evidence that they represent a novel class of olfactory receptor that allows the detection of diseased individuals or spoiled food.  And in case you’re wondering, there’s no evidence that FPRs are found in the olfactory system of humans – we only appear to have them in our immune system.

Rivière, S., Challet, L., Fluegge, D., Spehr, M., & Rodriguez, I. (2009). Formyl peptide receptor-like proteins are a novel family of vomeronasal chemosensors Nature, 459 (7246), 574-577 DOI: 10.1038/nature08029