About this Research Topic
Taste is the sense linked to food acceptance or rejection, a crucial aspect in ancient and modern life. Only a few years ago taste was named “the Cinderella of senses”, referring to the paucity of molecular biology studies on this sense, as compared to those on other senses. This research topic will mainly focus on the three tastes linked to food acceptance: sweet, bitter and umami.
The discovery of taste receptors has opened entirely new perspectives in the understanding of taste and, in a very few years, yielded many important results. For instance, it was soon established that there are several bitter taste receptors, needed to recognise the plethora of bitter molecules found in nature, but only one sweet receptor, even if there are many different sweet tasting molecules of widely different chemical nature. Recently sweet, bitter and umami chemoreceptors have been identified in extra-oral locations: here their activation and modulation by the same tastants in food, has a function that might be called pharmacological. These extra-oral receptors have been shown to be involved in the physiology of the respiratory system, innate immunity and endocrine system, including the digestive tract.
Experimental determination of the structure of taste receptors has not yet been achieved but modelling together with receptor mutagenesis have led to detailed mechanisms of interaction of tastants. It has been shown that each taste cell is labelled for an individual taste, although the alternatives of strict labelling and the possibility of cross talk among taste cells are still hotly debated.
It is timely to assess the state of the art of research on taste, from purely structural studies of receptors to their physiology. Among the main problems we wish to address with the present research topic are:
We still lack direct structural models of receptors. It is important to monitor any progress in experimental determinations of taste receptors and, at the same time, of bioinformatics approaches.
Genetics of taste receptors
Several polymorphisms in taste receptor have been identified, and correlations with food acceptance and rejection have been made. Also for some of the extra-oral functions of taste receptors it proved possible to define the relevance of genetics, but many questions are still open. Can we link taste receptors more explicitly to food acceptance and rejection or even attribute them a more general cognitive role? Are there relationships between some pathologies like inflammation and cancer and taste receptor polymorphism?
Detailed transduction mechanisms
Although transduction mechanisms of sweet, umami and bitter taste receptors are fairly well characterized, these “traditional” taste qualities are not the only taste signals detected by humans. The taste system can also sense non-traditional “tastes” as water and fat, but their reception mechanisms are not studied as much as the traditional ones.
Different contributions will be accepted, including reviews and perspectives, alongside regular original research articles.
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