St John's College Oxford

The sweet smell of research

Date 13 February 2018

On 6 February St John’s Research Centre hosted a fascinating workshop given by Professor Laura López-Mascaraque on the complexities of our sense of smell.

The event was proposed and coordinated by St John’s fellow Professor Zoltán Molnár of the Department of Physiology, Anatomy and Genetics. Professor López-Mascaraque is President of the Spanish Olfactory Society, at the Department of Molecular, Cellular and Developmental Neurobiology at the Instituto Cajal-CSIC in Madrid, Spain.

smell research workshop Feb 18Our sense of smell is the most sensitive and immediate of our senses, as the neurons in the brain are directly exposed to the environment. We can distinguish up to a billion different odours, and at the workshop participants explored how many they could distinguish, and at what concentrations, in a series of experiments. Given 12 boxes with different natural aromas, participants recognised them but found it curiously hard to name them. Once they heard the names, such as lemon, chocolate, or rose, they could connect them to the correct smell box.

smell research workshop Deb 18Smell and taste are intricately linked, in fact when we eat 80% of what we perceive is really smell. Participants explored whether or not they were ‘super-tasters’. This involved staining the tip of their tongue with food colouring, and asking a neighbour to count the number of taste buds in the stained area. Typically, non-tasters have fewer than 8 buds, average tasters have 8-13 buds, whereas super-tasters have more than 18 buds in a unit area.  

The participants explored whether they had the special ability to detect bitter flavours such as phenylthiocarbamide (PTC) more intensely than the average person. The ability to taste PTC (or not) is conveyed by a single gene, TAS2R38, that encodes a specific PTC receptor. Two alleles for this gene determine sensitive or non-sensitive receptors. People with two copies of the ‘non-sensitive’ allele are non-tasters, while those with some copy of the ‘sensitive’ allele are either tasters or super-tasters.

Finally, Professor López-Mascaraque explained how smells have some effects that are beyond our conscious control. Intimately linked to our emotions, they can powerfully affect our mood. Each of us has a characteristic smell that is genetically determined; the smell of our peers helps us to feel empathy and regulates our sexual and social behaviour. 

DPAG