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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Human handedness – inherited or developed?

August 3, 2010

This post is a little off the topic of what I normally write about, but its something I’ve been wondering about lately as the little munchkin grows up. She’s 6 months old now and is starting to use her hands a lot, going through that grabby stage where anything within arms length is grabbed and shoved in the mouth.  I’ve noticed that more often than not she’s using her left hand for this exploring.  It’s her left hand that grabs her left foot, and her left hand that grabs the spoon during my attempts to introduce her to the wonderful world of solid food.

Does this mean she’s going to be left-handed?  Coming from an extended family of determinedly right-handed people this comes as a bit of a surprise, and makes me wonder if there is an inherited component to handedness, or if there is some trigger during development that makes babies favour one hand over the other. Read the rest of this entry »


Sniffing out disease

June 4, 2009

ResearchBlogging.org

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


Chemical attraction?

March 24, 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”.

Perhaps even more excitingly though (for me at least), was the finding that individual tuatara secrete specific mixtures of these glycerides and that the makeup of these individual profiles remains stable over years. This could provide a mechanism for chemical recognition of individual tuatara, a finding which ties in nicely with some behavioural work we have recently been doing on tuatara.

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