Smell, molecular basis

Zarzo, M. (2007). The sense of smell Molecular basis of odorant recognition. Biol. Rev. 82, 455-479. 

Chadwick D., Marsh J. and Goode J., eds. (1993). The Molecular Basis of Smell and Taste Transduction. John Wiley, Chichester, p. 287. 

We are going to get back to the molecular basis for the human reactions to tastes and smells, examples of chemical communication, shortly. To get there, we need to start with substantially simpler systems of chemical communication and work our way up to more complex ones. As we move forward, we are going to focus on the consequences of small molecules interacting with large ones, molecular recognition, a pervasive theme of this book. 

T o properly recognize the smell of a particular molecule, each sensory neuron should express a single odorant receptor and respond to an appropriate range of odorants with similar molecular characteristics. This presumption (one receptor-one olfactory neuron rule) was deemed acceptable for quite some time but did not have a firm experimental basis until recently when it was demonstrated in the olfactory system of mice.206... 

Tbe basis Tor (be separation by bubbles and foam (adsorptive bubble separalion) is the difference in the surface activities of the various materials present in the solution or the suspension of interest. The material mey be cellular or colloidal substances, crystals, minerals, ionic or molecular compounds, precipitates, proteins, or bactemi, but in any case it must be surface active at the air-liquid interface (Fig. 17.1-1) These surface-active meterials tend to attach preferentially to (he air-liquid interfaces of the bubbles or fonme, As the bobbies or fonms rise throngh the columa or pool oftiquid, the attached material is removed. When this combination reachas the surface, the meierial can be removed in the relatively smell volume or collapsed foam or surface "scum. ... 

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