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Garbay J, Cameleyre M, Riquier L, Barbe JC, Lytra G. Development of a New Method for the Quantitative Analysis of Aroma Compounds Potentially Related to the Fruity Aroma of Red Wines. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13066-13078. [PMID: 37625117 DOI: 10.1021/acs.jafc.3c03267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
To determine the concentrations of aroma compounds involved in the fruity aroma of red wines, an analytical method was developed and optimized using liquid-liquid extraction and gas chromatography coupled to mass spectrometry (GC/MS). The aim was to reduce sample preparation and analysis time, with a single sample preparation and a single injection being needed to quantify 43 compounds. 19 esters, 13 monoterpenes, 5 C13-norisoprenoids, and 6 C6-aldehyde and alcohol compounds were quantified in 14 red wines made from different grape varieties grown in the Mediterranean basin. Samples were selected based on typical varietal aroma by a panel of experts, who produced 7 olfactory descriptors linked to desirable or non-desirable wine aromas. The instrumental analysis showed variations in concentrations of the quantified compounds among the wines. The wines described using positive fruity descriptors had higher mean total concentrations of esters, C6-alcohols, monoterpenes, and C13-norisoprenoids. Some non-ester compounds were positively correlated with the fruity descriptors. Sensory profile results obtained by a panel of 16 trained judges revealed that the addition of non-ester compounds (including 2 cyclic esters) to a red wine initially described as having cooked fruit aromas had a positive contribution to some fresh fruity notes. This study opens up new avenues for research on the potential involvement of non-ester compounds in the fruity expression of red wines.
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Affiliation(s)
- Justine Garbay
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, University of Bordeaux, F-33140 Villenave d'Ornon, France
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, Bordeaux Sciences Agro, F-33170 Gradignan, France
| | - Margaux Cameleyre
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, University of Bordeaux, F-33140 Villenave d'Ornon, France
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, Bordeaux Sciences Agro, F-33170 Gradignan, France
| | - Laurent Riquier
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, University of Bordeaux, F-33140 Villenave d'Ornon, France
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, Bordeaux Sciences Agro, F-33170 Gradignan, France
| | - Jean-Christophe Barbe
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, University of Bordeaux, F-33140 Villenave d'Ornon, France
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, Bordeaux Sciences Agro, F-33170 Gradignan, France
| | - Georgia Lytra
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, University of Bordeaux, F-33140 Villenave d'Ornon, France
- Bordeaux INP, INRAE, OENO, UMR 1366, ISVV, Bordeaux Sciences Agro, F-33170 Gradignan, France
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2
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Rugard M, Audouze K, Tromelin A. Combining the Classification and Pharmacophore Approaches to Understand Homogeneous Olfactory Perceptions at Peripheral Level: Focus on Two Aroma Mixtures. Molecules 2023; 28:molecules28104028. [PMID: 37241770 DOI: 10.3390/molecules28104028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/20/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023] Open
Abstract
The mechanisms involved in the homogeneous perception of odorant mixtures remain largely unknown. With the aim of enhancing knowledge about blending and masking mixture perceptions, we focused on structure-odor relationships by combining the classification and pharmacophore approaches. We built a dataset of about 5000 molecules and their related odors and reduced the multidimensional space defined by 1014 fingerprints representing the structures to a tridimensional 3D space using uniform manifold approximation and projection (UMAP). The self-organizing map (SOM) classification was then performed using the 3D coordinates in the UMAP space that defined specific clusters. We explored the allocating in these clusters of the components of two aroma mixtures: a blended mixture (red cordial (RC) mixture, 6 molecules) and a masking binary mixture (isoamyl acetate/whiskey-lactone [IA/WL]). Focusing on clusters containing the components of the mixtures, we looked at the odor notes carried by the molecules belonging to these clusters and also at their structural features by pharmacophore modeling (PHASE). The obtained pharmacophore models suggest that WL and IA could have a common binding site(s) at the peripheral level, but that would be excluded for the components of RC. In vitro experiments will soon be carried out to assess these hypotheses.
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Affiliation(s)
- Marylène Rugard
- T3S, Inserm UMR S-1124, Université Paris Cité, F-75006 Paris, France
| | - Karine Audouze
- T3S, Inserm UMR S-1124, Université Paris Cité, F-75006 Paris, France
| | - Anne Tromelin
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, F-21000 Dijon, France
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3
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Caton S, Dewan A. Olfaction: Allosteric modulation. Curr Biol 2023; 33:R311-R313. [PMID: 37098335 DOI: 10.1016/j.cub.2023.03.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
New research indicates that the odor-evoked responses of human olfactory receptors can be enhanced via the non-competitive binding of an allosteric modulator. This modulatory mechanism adds an additional layer of complexity to the peripheral encoding of odors.
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Affiliation(s)
- Samuel Caton
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
| | - Adam Dewan
- Department of Psychology, Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA.
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4
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Trimmer C, Arroyave R, Vuilleumier C, Wu L, Dumer A, DeLaura C, Kim J, Pierce GM, Borisovska M, De Nanteuil F, Emberger M, Varganov Y, Margot C, Rogers ME, Pfister P. Allosteric modulation of a human odorant receptor. Curr Biol 2023; 33:1523-1534.e4. [PMID: 36977419 DOI: 10.1016/j.cub.2023.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 12/02/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023]
Abstract
Odor perception is first determined by how the myriad of environmental volatiles are detected at the periphery of the olfactory system. The combinatorial activation of dedicated odorant receptors generates enough encoding power for the discrimination of tens of thousands of odorants. Recent studies have revealed that odorant receptors undergo widespread inhibitory modulation of their activity when presented with mixtures of odorants, a property likely required to maintain discrimination and ensure sparsity of the code for complex mixtures. Here, we establish the role of human OR5AN1 in the detection of musks and identify distinct odorants capable of enhancing its activity in binary mixtures. Chemical and pharmacological characterization indicate that specific α-β unsaturated aliphatic aldehydes act as positive allosteric modulators. Sensory experiments show decreased odor detection threshold in humans, suggesting that allosteric modulation of odorant receptors is perceptually relevant and likely adds another layer of complexity to how odors are encoded in the peripheral olfactory system.
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5
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Xu L, Zou DJ, Firestein S. Odor mixtures: A chord with silent notes. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1135486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The olfactory world is one of complex mixtures and blends containing up to hundreds of molecules. Many of those molecules can act as agonists, antagonists or enhancers at different receptors. This complicates the mechanism by which higher centers construct perceptions of complex mixtures. We propose that along with structural chemistry, psychophysics, the techniques of medicinal chemistry and machine learning can begin to shed light on this difficult neural problem.
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6
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Coureaud G, Thomas-Danguin T, Sandoz JC, Wilson DA. Biological constraints on configural odour mixture perception. J Exp Biol 2022; 225:274695. [PMID: 35285471 PMCID: PMC8996812 DOI: 10.1242/jeb.242274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Animals, including humans, detect odours and use this information to behave efficiently in the environment. Frequently, odours consist of complex mixtures of odorants rather than single odorants, and mixtures are often perceived as configural wholes, i.e. as odour objects (e.g. food, partners). The biological rules governing this 'configural perception' (as opposed to the elemental perception of mixtures through their components) remain weakly understood. Here, we first review examples of configural mixture processing in diverse species involving species-specific biological signals. Then, we present the original hypothesis that at least certain mixtures can be processed configurally across species. Indeed, experiments conducted in human adults, newborn rabbits and, more recently, in rodents and honeybees show that these species process some mixtures in a remarkably similar fashion. Strikingly, a mixture AB (A, ethyl isobutyrate; B, ethyl maltol) induces configural processing in humans, who perceive a mixture odour quality (pineapple) distinct from the component qualities (A, strawberry; B, caramel). The same mixture is weakly configurally processed in rabbit neonates, which perceive a particular odour for the mixture in addition to the component odours. Mice and honeybees also perceive the AB mixture configurally, as they respond differently to the mixture compared with its components. Based on these results and others, including neurophysiological approaches, we propose that certain mixtures are convergently perceived across various species of vertebrates/invertebrates, possibly as a result of a similar anatomical organization of their olfactory systems and the common necessity to simplify the environment's chemical complexity in order to display adaptive behaviours.
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Affiliation(s)
- Gérard Coureaud
- Centre de Recherche en Neurosciences de Lyon, Team Sensory Neuroethology (ENES), CNRS/INSERM/UCBL1/UJM, 69500 Lyon, France
| | - Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, Team Flavor, Food Oral Processing and Perception, INRAE, CNRS, Institut Agro Dijon, Université Bourgogne Franche-Comté, 21000 Dijon, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior and Ecology, CNRS, Université Paris-Saclay, IRD, 91190 Gif-sur-Yvette, France
| | - Donald A Wilson
- Department of Child & Adolescent Psychiatry, New York University Langone School of Medicine and Nathan S. Kline Institute for Psychiatric Research, New York, NY 10016, USA
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7
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Cameleyre M, Monsant C, Tempere S, Lytra G, Barbe JC. Toward a Better Understanding of Perceptive Interactions between Volatile and Nonvolatile Compounds: The Case of Proanthocyanidic Tannins and Red Wine Fruity Esters-Methodological, Sensory, and Physicochemical Approaches. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9895-9904. [PMID: 34403583 DOI: 10.1021/acs.jafc.1c02934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The impact of commercial proanthocyanidic tannins on fruity pool of esters, representing the fruitiness of Bordeaux red wines, was assessed in model solutions. It was shown that the presence of tannins in the matrix significantly attenuated perception of fruity notes (p = 0.013). Physicochemical analysis demonstrated that the presence of proanthocyanidic tannins in dilute alcohol solution resulted in a decrease in ester partition coefficients and thus in a decrease in ester contents in the headspace (p < 0.05). This fact highlighted the changes that may occur in wines at a pre-sensory level, prior to sensory evaluation. Finally, a new sensory tool was developed, consisting in an ISO glass containing two compartments separated by a glass wall, providing a way to compare perceived odors according to whether or not the components of the odor mixtures were actually mixed in solution (p < 0.001). This new tool was used to demonstrate the impact and the only implication of pre-sensory level in the consequences of physical mixture between proanthocyanidic tannins and esters on their odor perception.
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Affiliation(s)
- Margaux Cameleyre
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon, France
| | - Clémence Monsant
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon, France
| | - Sophie Tempere
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon, France
| | - Georgia Lytra
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon, France
| | - Jean-Christophe Barbe
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F-33882 Villenave d'Ornon, France
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8
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Corey EA, Zolotukhin S, Ache BW, Ukhanov K. Mixture interactions at mammalian olfactory receptors are dependent on the cellular environment. Sci Rep 2021; 11:9278. [PMID: 33927269 PMCID: PMC8085013 DOI: 10.1038/s41598-021-88601-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/07/2021] [Indexed: 02/02/2023] Open
Abstract
Functional characterization of mammalian olfactory receptors (ORs) remains a major challenge to ultimately understanding the olfactory code. Here, we compare the responses of the mouse Olfr73 ectopically expressed in olfactory sensory neurons using AAV gene delivery in vivo and expressed in vitro in cell culture. The response dynamics and concentration-dependence of agonists for the ectopically expressed Olfr73 were similar to those reported for the endogenous Olfr73, however the antagonism previously reported between its cognate agonist and several antagonists was not replicated in vivo. Expressing the OR in vitro reproduced the antagonism reported for short odor pulses, but not for prolonged odor exposure. Our findings suggest that both the cellular environment and the stimulus dynamics shape the functionality of Olfr73 and argue that characterizing ORs in 'native' conditions, rather than in vitro, provides a more relevant understanding of ligand-OR interactions.
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Affiliation(s)
- Elizabeth A Corey
- Whitney Laboratory, University of Florida, Gainesville, FL, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA
| | - Sergei Zolotukhin
- Department of Pediatrics, University of Florida, Gainesville, FL, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA
| | - Barry W Ache
- Whitney Laboratory, University of Florida, Gainesville, FL, USA
- Department of Biology and Neuroscience, University of Florida, Gainesville, FL, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Kirill Ukhanov
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA.
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
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9
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Duchamp-Viret P, Boyer J, La Villa F, Coureaud G. Brief olfactory learning drives perceptive sensitivity in newborn rabbits: New insights in peripheral processing of odor mixtures and induction. Physiol Behav 2021; 229:113217. [PMID: 33098882 DOI: 10.1016/j.physbeh.2020.113217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/29/2020] [Accepted: 10/20/2020] [Indexed: 11/19/2022]
Abstract
Perception of the wide, complex and moving odor world requires that the olfactory system engages processing mechanisms ensuring detection, discrimination and environment adaptation, as early as the peripheral stages. Odor items are mainly elicited by odorant mixtures which give rise to either elemental or configural perceptions. Here, we first explored the contribution of the peripheral olfactory system to configural and elemental perception through odorant interactions at the olfactory receptor (OR) level. This was done in newborn rabbits, which offer the opportunity to pair peripheral electrophysiology and well characterized behavioral responses to two binary mixtures, AB and A'B', which differ in their component ratio (A: ethyl isobutyrate, B: ethyl maltol), and that rabbit pups respectively perceived configurally and elementally. Second, we studied the influence on peripheral reactivity of the brief but powerful learning of one mixture component (odorant B), conditioned by association with the mammary pheromone (MP), which allowed us to assess the possible implication of the phenomenon called induction in neonatal odor learning. Induction is a plasticity mechanism expected to alter both the peripheral electrophysiological responses to, and perceptual detection threshold of, the conditioned stimulus. The results reveal that perceptual modes are partly rooted in differential peripheral processes, the AB configurally perceived mixture mirroring odorant antagonist interactions at OR level to a lesser extent than the A'B' elementally perceived mixture. Further, the results highlight that a single and brief MP-induced odor learning episode is sufficient to alter peripheral responses to the conditioned stimulus and mixtures including it, and shifts the conditioned stimulus detection threshold towards lower concentrations. Thus, MP-induced odor learning relies on induction phenomenon in newborn rabbits.
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Affiliation(s)
- Patricia Duchamp-Viret
- Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U 1028 - Université Claude Bernard Lyon 1, Centre Hospitalier Le Vinatier - Bâtiment 462 - Neurocampus, 95 Boulevard Pinel, 69675 Bron Cedex, FRANCE.
| | - Jiasmine Boyer
- Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U 1028 - Université Claude Bernard Lyon 1, Centre Hospitalier Le Vinatier - Bâtiment 462 - Neurocampus, 95 Boulevard Pinel, 69675 Bron Cedex, FRANCE
| | - Florian La Villa
- Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U 1028 - Université Claude Bernard Lyon 1, Centre Hospitalier Le Vinatier - Bâtiment 462 - Neurocampus, 95 Boulevard Pinel, 69675 Bron Cedex, FRANCE
| | - Gérard Coureaud
- Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U 1028 - Université Claude Bernard Lyon 1, Centre Hospitalier Le Vinatier - Bâtiment 462 - Neurocampus, 95 Boulevard Pinel, 69675 Bron Cedex, FRANCE.
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10
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Kuroki R, Sakano R, Hattori S, Morishita S. Comparing odor-active compounds in three mango (<i>Mangifera indica</i> L.) cultivars by aroma extract dilution analysis and the method for evaluating odor interactions. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2021. [DOI: 10.3136/fstr.27.103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Kurian SM, Naressi RG, Manoel D, Barwich AS, Malnic B, Saraiva LR. Odor coding in the mammalian olfactory epithelium. Cell Tissue Res 2021; 383:445-456. [PMID: 33409650 PMCID: PMC7873010 DOI: 10.1007/s00441-020-03327-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/27/2020] [Indexed: 12/31/2022]
Abstract
Noses are extremely sophisticated chemical detectors allowing animals to use scents to interpret and navigate their environments. Odor detection starts with the activation of odorant receptors (ORs), expressed in mature olfactory sensory neurons (OSNs) populating the olfactory mucosa. Different odorants, or different concentrations of the same odorant, activate unique ensembles of ORs. This mechanism of combinatorial receptor coding provided a possible explanation as to why different odorants are perceived as having distinct odors. Aided by new technologies, several recent studies have found that antagonist interactions also play an important role in the formation of the combinatorial receptor code. These findings mark the start of a new era in the study of odorant-receptor interactions and add a new level of complexity to odor coding in mammals.
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Affiliation(s)
| | | | | | | | - Bettina Malnic
- Department of Biochemistry, University of São Paulo, São Paulo, Brazil.
| | - Luis R Saraiva
- Sidra Medicine, Doha, Qatar.
- Monell Chemical Senses Center, Philadelphia, USA.
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
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12
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Cameleyre M, Lytra G, Schütte L, Vicard JC, Barbe JC. Oak Wood Volatiles Impact on Red Wine Fruity Aroma Perception in Various Matrices. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:13319-13330. [PMID: 32286816 DOI: 10.1021/acs.jafc.0c00583] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This research examined the impact of oak wood volatile compounds on the perception of red wine fruity aroma in several matrices. Several aromatic reconstitutions were prepared, consisting of 13 esters, representing the fruity pool of red wine, and 14 oak wood compounds at the various concentrations corresponding to the levels released by light, medium, and heavy toasting of barrels. These reconstitutions were prepared in dilute alcohol solution, dearomatized red wine, and commercial red wine. Sensory analysis revealed the impact of the addition or omission of some oak wood compounds. The "detection threshold" of the fruity pool was then evaluated. The presence of 2-furanmethanethiol individually and the oak wood compound mixture, at concentrations representing various toasting levels, had a significant masking effect on the fruity pool, whereas vanillin had a significant enhancing effect in model solution. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the oak wood compound mixture. The addition of compounds at concentrations representing different toasting levels led to a predictable increase in the perception of the oak wood descriptors (spicy, smoky, and toasty) in all of the matrices tested. The perception of fruity notes also varied depending upon the toasting level and the complexity of the matrix. In dilute alcohol solution and dearomatized red wine, light toasting preserved or intensified the fruity notes. Generally, in all matrices tested, fresh-fruit and red-berry-fruit notes decreased with the addition of wood at medium and heavy toasting levels.
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Affiliation(s)
- Margaux Cameleyre
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d'Ornon, France
| | - Georgia Lytra
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d'Ornon, France
| | - Larissa Schütte
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d'Ornon, France
| | | | - Jean-Christophe Barbe
- Unité de Recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, Université de Bordeaux, F33882 Villenave d'Ornon, France
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13
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Cameleyre M, Madrelle V, Lytra G, Barbe JC. Impact of Whisky Lactone Diastereoisomers on Red Wine Fruity Aromatic Expression in Model Solution. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:10808-10814. [PMID: 32915562 DOI: 10.1021/acs.jafc.0c04200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The impact of whisky lactone diastereoisomers on the typical fruity expression of red Bordeaux wines was evaluated by sensory analysis. The detection thresholds of cis- and trans-whisky lactone in a dilute alcohol solution (12% v/v) were 20 and 130 μg/L, respectively. Consequently, considering their average concentrations found in oak-aged red wines, cis-whisky lactone was present at supra threshold levels, whereas trans-whisky lactone was below its detection threshold. Adding these diastereoisomers to a red wine fruity aromatic reconstitution at these average concentrations led to a decrease in the perception of this last one, highlighting a masking effect. Sensory profiles of cis- and trans-whisky lactone confirmed that these compounds modified the perception of fruity aromas, decreasing the intensity of red berry fruit notes and increasing that of blackberry fruit and spicy descriptors.
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Affiliation(s)
- Margaux Cameleyre
- Université de Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, 33882 Villenave d'Ornon Cedex, France
| | - Victoria Madrelle
- Université de Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, 33882 Villenave d'Ornon Cedex, France
| | - Georgia Lytra
- Université de Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, 33882 Villenave d'Ornon Cedex, France
| | - Jean-Christophe Barbe
- Université de Bordeaux, Unité de recherche Œnologie, EA 4577, USC 1366 INRAE, ISVV, 33882 Villenave d'Ornon Cedex, France
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14
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McKay M, Bauer FF, Panzeri V, Buica A. Investigating the effects of two volatile phenols on aroma perception of four red wine cultivars using Projective Mapping. J SENS STUD 2020. [DOI: 10.1111/joss.12616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marianne McKay
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology Stellenbosch University Stellenbosch South Africa
| | - Florian F. Bauer
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology Stellenbosch University Stellenbosch South Africa
| | - Valeria Panzeri
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology Stellenbosch University Stellenbosch South Africa
| | - Astrid Buica
- South African Grape and Wine Research Institute, Department of Viticulture and Oenology Stellenbosch University Stellenbosch South Africa
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15
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Abstract
Odor receptors of the mammalian olfactory system have long been known to be activated in combinatorial fashion by odorants. A large-scale study now reveals that inhibition of receptors by odorants is comparably prevalent and combinatorial.
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Affiliation(s)
- Douglas Rioux
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - John R Carlson
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA.
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16
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Pfister P, Smith BC, Evans BJ, Brann JH, Trimmer C, Sheikh M, Arroyave R, Reddy G, Jeong HY, Raps DA, Peterlin Z, Vergassola M, Rogers ME. Odorant Receptor Inhibition Is Fundamental to Odor Encoding. Curr Biol 2020; 30:2574-2587.e6. [PMID: 32470365 DOI: 10.1016/j.cub.2020.04.086] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/31/2020] [Accepted: 04/28/2020] [Indexed: 11/18/2022]
Abstract
Most natural odors are complex mixtures of volatile components, competing to bind odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) of the nose. To date, surprisingly little is known about how OR antagonism shapes neuronal representations in the detection layer of the olfactory system. Here, we investigated its prevalence, the degree to which it disrupts OR ensemble activity, and its conservation across phylogenetically related ORs. Calcium imaging microscopy of dissociated OSNs revealed significant inhibition, often complete attenuation, of responses to indole-a commonly occurring volatile associated with both floral and fecal odors-by a set of 36 tested odorants. To confirm an OR mechanism for the observed inhibition, we performed single-cell transcriptomics on OSNs exhibiting specific response profiles to a diagnostic panel of odorants and identified three paralogous receptors-Olfr740, Olfr741, and Olfr743-which, when tested in vitro, recapitulated OSN responses. We screened ten ORs from the Olfr740 gene family with ∼800 perfumery-related odorants spanning a range of chemical scaffolds and functional groups. Over half of these compounds (430) antagonized at least one of the ten ORs. OR activity fitted a mathematical model of competitive receptor binding and suggests normalization of OSN ensemble responses to odorant mixtures is the rule rather than the exception. In summary, we observed OR antagonism occurred frequently and in a combinatorial manner. Thus, extensive receptor-mediated computation of mixture information appears to occur in the olfactory epithelium prior to transmission of odor information to the olfactory bulb.
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Affiliation(s)
- Patrick Pfister
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Benjamin C Smith
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Barry J Evans
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Jessica H Brann
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Casey Trimmer
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Mushhood Sheikh
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Randy Arroyave
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Gautam Reddy
- Department of Physics, UC San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Hyo-Young Jeong
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Daniel A Raps
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Zita Peterlin
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Massimo Vergassola
- Department of Physics, UC San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Matthew E Rogers
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA.
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17
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Zak JD, Reddy G, Vergassola M, Murthy VN. Antagonistic odor interactions in olfactory sensory neurons are widespread in freely breathing mice. Nat Commun 2020; 11:3350. [PMID: 32620767 PMCID: PMC7335155 DOI: 10.1038/s41467-020-17124-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/10/2020] [Indexed: 12/24/2022] Open
Abstract
Odor landscapes contain complex blends of molecules that each activate unique, overlapping populations of olfactory sensory neurons (OSNs). Despite the presence of hundreds of OSN subtypes in many animals, the overlapping nature of odor inputs may lead to saturation of neural responses at the early stages of stimulus encoding. Information loss due to saturation could be mitigated by normalizing mechanisms such as antagonism at the level of receptor-ligand interactions, whose existence and prevalence remains uncertain. By imaging OSN axon terminals in olfactory bulb glomeruli as well as OSN cell bodies within the olfactory epithelium in freely breathing mice, we find widespread antagonistic interactions in binary odor mixtures. In complex mixtures of up to 12 odorants, antagonistic interactions are stronger and more prevalent with increasing mixture complexity. Therefore, antagonism is a common feature of odor mixture encoding in OSNs and helps in normalizing activity to reduce saturation and increase information transfer.
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Affiliation(s)
- Joseph D Zak
- Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA, 02138, USA.
- Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA.
| | - Gautam Reddy
- NSF-Simons Center for Mathematical & Statistical Analysis of Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Massimo Vergassola
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, F-75005, France
| | - Venkatesh N Murthy
- Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA, 02138, USA.
- Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA.
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18
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Exploring the Characteristics of an Aroma-Blending Mixture by Investigating the Network of Shared Odors and the Molecular Features of Their Related Odorants. Molecules 2020; 25:molecules25133032. [PMID: 32630789 PMCID: PMC7411594 DOI: 10.3390/molecules25133032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 11/16/2022] Open
Abstract
The perception of aroma mixtures is based on interactions beginning at the peripheral olfactory system, but the process remains poorly understood. The perception of a mixture of ethyl isobutyrate (Et-iB, strawberry-like odor) and ethyl maltol (Et-M, caramel-like odor) was investigated previously in both human and animal studies. In those studies, the binary mixture of Et-iB and Et-M was found to be configurally processed. In humans, the mixture was judged as more typical of a pineapple odor, similar to allyl hexanoate (Al-H, pineapple-like odor), than the odors of the individual components. To explore the key features of this aroma blend, we developed an in silico approach based on molecules having at least one of the odors—strawberry, caramel or pineapple. A dataset of 293 molecules and their related odors was built. We applied the notion of a “social network” to describe the network of the odors. Additionally, we explored the structural properties of the molecules in this dataset. The network of the odors revealed peculiar links between odors, while the structural study emphasized key characteristics of the molecules. The association between “strawberry” and “caramel” notes, as well as the structural diversity of the “strawberry” molecules, were notable. Such elements would be key to identifying potential odors/odorants to form aroma blends.
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19
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Liu DT, Besser G, Lang M, Sharma G, Pablik E, Renner B, Mueller CA. Odor Mixtures in Identification Testing Using Sniffin' Sticks: The SSomix Test. Sci Rep 2020; 10:8155. [PMID: 32424128 PMCID: PMC7234997 DOI: 10.1038/s41598-020-65028-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 04/27/2020] [Indexed: 11/29/2022] Open
Abstract
Clinical tests assessing olfactory performance have become indispensable for diagnosing olfactory dysfunction. As time and personnel resources are limited, it would be advantageous to have shorter protocols focusing on singular aspects of olfactory performance, such as odor identification. However, such a unidimensional approach is often inconclusive and needs further tests (and tools). Hence, new testing methods with high levels of sensitivity, specificity, and reproducibility are required for clinical practice. Here, we developed a Sniffin’ Sticks odor mixture identification test method (SSomix), with emphasis on resource efficiency and simplicity of administration. SSomix consists of mixtures of two and three odors applied onto a piece of paper using 11 out of 16 items from the original Sniffin’ Sticks identification test kit. A total of 66 healthy subjects and 22 patients with olfactory dysfunction were included in the study. SSomix showed good to excellent test-retest reliability and validity. The area under the receiver operating characteristics curves indicated good diagnostic accuracy in identifying patients with reduced and severely impaired olfactory function. SSomix was a suitable downsizing of the original kit, especially regarding resource efficiency.
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Affiliation(s)
- David Tianxiang Liu
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Gerold Besser
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Miriam Lang
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Gunjan Sharma
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Eleonore Pablik
- Section for Medical Statistics, CeMSIIS, Medical University of Vienna, Vienna, Austria
| | - Bertold Renner
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Institute of Clinical Pharmacology, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Christian Albert Mueller
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
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20
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Xu L, Li W, Voleti V, Zou DJ, Hillman EMC, Firestein S. Widespread receptor-driven modulation in peripheral olfactory coding. Science 2020; 368:368/6487/eaaz5390. [PMID: 32273438 DOI: 10.1126/science.aaz5390] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 03/09/2020] [Indexed: 12/24/2022]
Abstract
Olfactory responses to single odors have been well characterized but in reality we are continually presented with complex mixtures of odors. We performed high-throughput analysis of single-cell responses to odor blends using Swept Confocally Aligned Planar Excitation (SCAPE) microscopy of intact mouse olfactory epithelium, imaging ~10,000 olfactory sensory neurons in parallel. In large numbers of responding cells, mixtures of odors did not elicit a simple sum of the responses to individual components of the blend. Instead, many neurons exhibited either antagonism or enhancement of their response in the presence of another odor. All eight odors tested acted as both agonists and antagonists at different receptors. We propose that this peripheral modulation of responses increases the capacity of the olfactory system to distinguish complex odor mixtures.
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Affiliation(s)
- Lu Xu
- Department of Biological Sciences, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Wenze Li
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Sciences, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Venkatakaushik Voleti
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Sciences, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Dong-Jing Zou
- Department of Biological Sciences, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Departments of Biomedical Engineering and Radiology, Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Sciences, Columbia University in the City of New York, New York, NY, 10027, USA.
| | - Stuart Firestein
- Department of Biological Sciences, Columbia University in the City of New York, New York, NY, 10027, USA.
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21
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de March CA, Titlow WB, Sengoku T, Breheny P, Matsunami H, McClintock TS. Modulation of the combinatorial code of odorant receptor response patterns in odorant mixtures. Mol Cell Neurosci 2020; 104:103469. [PMID: 32061665 DOI: 10.1016/j.mcn.2020.103469] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 02/01/2023] Open
Abstract
The perception of odors relies on combinatorial codes consisting of odorant receptor (OR) response patterns to encode odor identity. Modulation of these patterns by odorant interactions at ORs potentially explains several olfactory phenomena: mixture suppression, unpredictable sensory outcomes, and the perception of odorant mixtures as unique objects. We determined OR response patterns to 4 odorants and 3 binary mixtures in vivo in mice, identifying 30 responsive ORs. These patterns typically had a few strongly responsive ORs and a greater number of weakly responsive ORs. ORs responsive to an odorant were often unrelated sequences distributed across several OR subfamilies. Mixture responses predicted pharmacological interactions between odorants, which were tested in vitro by heterologous expression of ORs in cultured cells, providing independent evidence confirming odorant agonists for 13 ORs and identifying both suppressive and additive effects. This included 11 instances of antagonism of ORs by an odorant, 1 instance of additive responses to a binary mixture, 1 instance of suppression of a strong agonist by a weak agonist, and the discovery of an inverse agonist for an OR. Interactions between odorants at ORs are common even when the odorants are not known to interact perceptually in humans, and in some cases interactions at mouse ORs correlate with the ability of humans to perceive an odorant in a mixture.
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Affiliation(s)
- Claire A de March
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - William B Titlow
- Department of Physiology, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Tomoko Sengoku
- Department of Physiology, University of Kentucky, Lexington, KY 40536-0298, USA
| | - Patrick Breheny
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA; Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan; Duke Institute for Brain Sciences, Duke University, Durham, NC 27710, USA.
| | - Timothy S McClintock
- Department of Physiology, University of Kentucky, Lexington, KY 40536-0298, USA.
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22
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Müschenich FS, Sijben R, Gallenmüller F, Singer M, Rodriguez-Raecke R, Di Francesco ME, Wiesmann M, Freiherr J. Eucalyptol Masks the Olfactory But Not the Trigeminal Sensation of Ammonia. Chem Senses 2019; 44:733-741. [PMID: 31541234 DOI: 10.1093/chemse/bjz065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Eucalyptol is a substance with rather pleasant olfactory and trigeminal characteristics and is thus suggested as an efficient tool for malodor coverage. In this study ammonia would be the malodor substance such as is found in cat litter or hair coloration. We investigated the potential of eucalyptol to inhibit both the olfactory as well as the trigeminal sensation of ammonia. For this purpose, we mixed eucalyptol and ammonia and compared odor component intensities. After being presented with either the pure odors or a binary mixture thereof, 21 young and healthy participants had to lateralize the odors and rate component (eucalyptol and ammonia) and total intensity. Analysis of intensity ratings revealed hypoadditivity (total mixture intensity was less than the sum of the total intensity of the single components). Significant interaction effects verified that mixing eucalyptol and ammonia only affected the perceived intensity of ammonia. Comparing the odor components within the pure and mixed stimuli, the ammonia component was rated as significantly less intense in the mixture compared to pure ammonia whereas the eucalyptol component was rated equal in the pure and mixed condition. On the basis of lateralization scores, we observed trigeminal mixture enhancement. We conclude that eucalyptol is a suitable masking agent to cover the unpleasant smell of ammonia; however, it fails to serve as an ammonia counterirritant because it lacks the ability to mask the trigeminal sensation of ammonia.
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Affiliation(s)
| | - Rik Sijben
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Felix Gallenmüller
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Marco Singer
- Symrise AG, Division Scent and Care, Holzminden, Germany
| | - Rea Rodriguez-Raecke
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | | | - Martin Wiesmann
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Jessica Freiherr
- Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany.,Fraunhofer Institute for Process Engineering and Packaging IVV, Freising, Germany.,Friedrich-Alexander University Erlangen-Nürnberg, Department of Psychiatry and Psychotherapy, Erlangen, Germany
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23
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Kaur R, Kukkar D, Bhardwaj SK, Kim KH, Deep A. Potential use of polymers and their complexes as media for storage and delivery of fragrances. J Control Release 2018; 285:81-95. [DOI: 10.1016/j.jconrel.2018.07.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 11/15/2022]
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24
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Cameleyre M, Lytra G, Barbe JC. Static Headspace Analysis Using Low-Pressure Gas Chromatography and Mass Spectrometry, Application to Determining Multiple Partition Coefficients: A Practical Tool for Understanding Red Wine Fruity Volatile Perception and the Sensory Impact of Higher Alcohols. Anal Chem 2018; 90:10812-10818. [PMID: 30148602 DOI: 10.1021/acs.analchem.8b01896] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To evaluate the partition coefficients of volatiles between the liquid and gas phases, an analytical method was developed and optimized using static headspace analysis and low-pressure injection gas chromatography coupled to mass spectrometry (SHS-LP-GC/MS). Two different types of analytical columns were coupled for low-pressure chromatography injection: a narrow restriction microbore column on the inlet side and a mega-bore column on the mass spectrometer side. Coupling these two columns and static headspace analysis to gas chromatography and mass spectrometry resulted in a simple, fast, sensitive, and accurate approach. Several points have been optimized: time to reach the thermodynamic equilibrium in the gas phase, syringe filling rate, gas injection rate, and volume ratio between the gas and liquid phases. This new method was used to determine partition coefficients between the liquid and gas phases and study multicomponent mixtures for which particular perceptive interactions had previously been highlighted. The partition coefficients of 9 esters and 5 higher alcohols were determined in dilute alcohol solution (12% v/v) and dearomatized red wine. These partition coefficients revealed modifications in ester headspace release in the presence of higher alcohols for the first time in this type of matrix. The correlation of these results with sensory data highlighted the role of physicochemical, presensory effects on sensory modifications for the first time, suggesting that this type of interaction may partly modulate qualitative and quantitative fruity perception.
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Affiliation(s)
- Margaux Cameleyre
- University of Bordeaux , Unité de Recherche Oenologie, EA 4577, USC 1366 INRA, ISVV , 33882 Villenave d'Ornon Cedex, France
| | - Georgia Lytra
- University of Bordeaux , Unité de Recherche Oenologie, EA 4577, USC 1366 INRA, ISVV , 33882 Villenave d'Ornon Cedex, France
| | - Jean-Christophe Barbe
- University of Bordeaux , Unité de Recherche Oenologie, EA 4577, USC 1366 INRA, ISVV , 33882 Villenave d'Ornon Cedex, France
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25
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Reddy G, Zak JD, Vergassola M, Murthy VN. Antagonism in olfactory receptor neurons and its implications for the perception of odor mixtures. eLife 2018; 7:34958. [PMID: 29687778 PMCID: PMC5915184 DOI: 10.7554/elife.34958] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/30/2018] [Indexed: 11/16/2022] Open
Abstract
Natural environments feature mixtures of odorants of diverse quantities, qualities and complexities. Olfactory receptor neurons (ORNs) are the first layer in the sensory pathway and transmit the olfactory signal to higher regions of the brain. Yet, the response of ORNs to mixtures is strongly non-additive, and exhibits antagonistic interactions among odorants. Here, we model the processing of mixtures by mammalian ORNs, focusing on the role of inhibitory mechanisms. We show how antagonism leads to an effective ‘normalization’ of the ensemble ORN response, that is, the distribution of responses of the ORN population induced by any mixture is largely independent of the number of components in the mixture. This property arises from a novel mechanism involving the distinct statistical properties of receptor binding and activation, without any recurrent neuronal circuitry. Normalization allows our encoding model to outperform non-interacting models in odor discrimination tasks, leads to experimentally testable predictions and explains several psychophysical experiments in humans. When ordering in a coffee shop, you probably recognize and enjoy the aroma of freshly roasted coffee beans. But as well as coffee, you can also smell the croissants behind the counter and maybe even the perfume or cologne of the person next to you. Each of these scents consists of a collection of chemicals, or odorants. To distinguish between the aroma of coffee and that of croissants, your brain must group the odorants appropriately and then keep the groups separate from each other. This is not a trivial task. Odorants bind to proteins called odorant receptors found on the surface of cells in the nose called olfactory receptor neurons. But each odorant does not have its own dedicated receptor. Instead, a single odorant will bind to multiple types of odorant receptors, and thus, each olfactory receptor neuron may respond to multiple odorants. So how does the brain encode mixtures of odorants in a way that allows us to distinguish one aroma from another? Reddy, Zak et al. have developed a computational model to explain how this process works. The model assumes that an odorant triggers a response in an olfactory receptor neuron via two steps. First, the odorant binds to an odorant receptor. Second, the bound odorant activates the receptor. But the odorant that binds most strongly to a receptor will not necessarily be the odorant that is best at activating that receptor. This allows a phenomenon called competitive antagonism to occur. This is when one odorant in a mixture binds more strongly to a receptor than the other odorants, but only weakly activates that receptor. In so doing, the strongly bound odorant prevents the other odorants from binding to and activating the receptor. This helps tame the dominating influence of background odors, which might otherwise saturate the responses of individual olfactory receptor neurons. Reddy, Zak et al. show that processes such as competitive antagonism enable olfactory receptor neurons to encode all of the odors within a mixture. The model can explain various phenomena observed in experiments and it adds to our understanding of how the brain generates our sense of smell. The model may also be relevant to other biological systems that must filter weak signals from a dominant background. These include the immune system, which must distinguish a small set of foreign proteins from the much larger number of proteins that make up our bodies.
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Affiliation(s)
- Gautam Reddy
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Joseph D Zak
- Department of Molecular Cellular Biology, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Massimo Vergassola
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Venkatesh N Murthy
- Department of Molecular Cellular Biology, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
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26
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In Vivo Electrophysiological Recordings of Olfactory Receptor Neuron Units and Electro-olfactograms in Anesthetized Rats. Methods Mol Biol 2018; 1820:123-135. [PMID: 29884942 DOI: 10.1007/978-1-4939-8609-5_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In vivo recordings of single olfactory receptor neurons and electro-olfactograms (EOG, field potentials from the olfactory mucosa) provide insights into the olfactory processing properties of the olfactory peripheral stage. Because the olfactory receptor neurons are very small electrical generators, it is not easy to unitarily record them in amphibians, reptilians, and fishes. In mammals such recordings are even more difficult to obtain: primarily due to the anatomical configuration in complex turbinates of the olfactory mucosa and its propensity to hemorrhage during surgery; secondarily due to the fact that olfactory receptor neurons are held in closely packed clusters in the olfactory mucosa and are difficult to isolate, from the electrophysiological recording point of view. Here we describe the material and methods we used in vivo, in rats-occasionally, also tested in mice-to get simultaneously receptor neuron single and electro-olfactogram recordings, from septal region or the endoturbinate II, in freely breathing or tracheotomized anesthetized animals. Recording EOG in parallel with receptor neuron units provide, by reflecting the population response to the olfactory stimulus, the continuous assurance of the good physiological state and reactivity of the olfactory epithelium. This configuration will ensure that when a single ORN does not respond to a stimulus it resulted from its qualitative selectivity and not from the olfactory mucosa damaged status.
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27
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Odorant-odorant metabolic interaction, a novel actor in olfactory perception and behavioral responsiveness. Sci Rep 2017; 7:10219. [PMID: 28860551 PMCID: PMC5579276 DOI: 10.1038/s41598-017-10080-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/27/2017] [Indexed: 11/23/2022] Open
Abstract
In the nasal olfactory epithelium, olfactory metabolic enzymes ensure odorant clearance from the olfactory receptor environment. This biotransformation of odorants into deactivated polar metabolites is critical to maintaining peripheral sensitivity and perception. Olfactory stimuli consist of complex mixtures of odorants, so binding interactions likely occur at the enzyme level and may impact odor processing. Here, we used the well-described model of mammary pheromone-induced sucking-related behavior in rabbit neonates. It allowed to demonstrate how the presence of different aldehydic odorants efficiently affects the olfactory metabolism of this pheromone (an aldehyde too: 2-methylbut-2-enal). Indeed, according to in vitro and ex vivo measures, this metabolic interaction enhances the pheromone availability in the epithelium. Furthermore, in vivo presentation of the mammary pheromone at subthreshold concentrations efficiently triggers behavioral responsiveness in neonates when the pheromone is in mixture with a metabolic challenger odorant. These findings reveal that the periphery of the olfactory system is the place of metabolic interaction between odorants that may lead, in the context of odor mixture processing, to pertinent signal detection and corresponding behavioral effect.
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28
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Masking of Several Olfactory Notes by Infra-threshold Concentrations of 2,4,6-Trichloroanisole. CHEMOSENS PERCEPT 2017. [DOI: 10.1007/s12078-017-9227-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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29
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Thomsen M, Dosne T, Beno N, Chabanet C, Guichard E, Thomas‐Danguin T. Combination of odour‐stimulation tools and surface response methodology for odour recombination studies. FLAVOUR FRAG J 2017. [DOI: 10.1002/ffj.3376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Maiken Thomsen
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
| | - Thibaut Dosne
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
| | - Noëlle Beno
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
| | - Claire Chabanet
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
| | - Elisabeth Guichard
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
| | - Thierry Thomas‐Danguin
- CSGA (Centre des Sciences du Goût et de l'Alimentation), AgroSupDijon, INRA, CNRS Univ. Bourgogne Franche‐Comté 21000 Dijon France
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El Mountassir F, Belloir C, Briand L, Thomas-Danguin T, Le Bon AM. Encoding odorant mixtures by human olfactory receptors. FLAVOUR FRAG J 2016. [DOI: 10.1002/ffj.3331] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Fouzia El Mountassir
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA; Univ. Bourgogne Franche-Comté; F-21000 Dijon France
| | - Christine Belloir
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA; Univ. Bourgogne Franche-Comté; F-21000 Dijon France
| | - Loïc Briand
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA; Univ. Bourgogne Franche-Comté; F-21000 Dijon France
| | - Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA; Univ. Bourgogne Franche-Comté; F-21000 Dijon France
| | - Anne-Marie Le Bon
- Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA; Univ. Bourgogne Franche-Comté; F-21000 Dijon France
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31
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Tempere S, Schaaper M, Cuzange E, de Lescar R, de Revel G, Sicard G. The olfactory masking effect of ethylphenols: Characterization and elucidation of its origin. Food Qual Prefer 2016. [DOI: 10.1016/j.foodqual.2016.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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32
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Marchal S, Bregeras O, Puaux D, Gervais R, Ferry B. Rigorous Training of Dogs Leads to High Accuracy in Human Scent Matching-To-Sample Performance. PLoS One 2016; 11:e0146963. [PMID: 26863620 PMCID: PMC4749222 DOI: 10.1371/journal.pone.0146963] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 12/23/2015] [Indexed: 01/10/2023] Open
Abstract
Human scent identification is based on a matching-to-sample task in which trained dogs are required to compare a scent sample collected from an object found at a crime scene to that of a suspect. Based on dogs’ greater olfactory ability to detect and process odours, this method has been used in forensic investigations to identify the odour of a suspect at a crime scene. The excellent reliability and reproducibility of the method largely depend on rigor in dog training. The present study describes the various steps of training that lead to high sensitivity scores, with dogs matching samples with 90% efficiency when the complexity of the scents presented during the task in the sample is similar to that presented in the in lineups, and specificity reaching a ceiling, with no false alarms in human scent matching-to-sample tasks. This high level of accuracy ensures reliable results in judicial human scent identification tests. Also, our data should convince law enforcement authorities to use these results as official forensic evidence when dogs are trained appropriately.
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Affiliation(s)
- Sophie Marchal
- Division of the Technical and Scientific Police (DTSP), Central Direction of the Judicial Police, Central Service of the Judicial Identity, Forensic Section, 31 Avenue Franklin Roosevelt, F-69134, Ecully, Cedex, France
| | - Olivier Bregeras
- Division of the Technical and Scientific Police (DTSP), Central Direction of the Judicial Police, Central Service of the Judicial Identity, Forensic Section, 31 Avenue Franklin Roosevelt, F-69134, Ecully, Cedex, France
| | - Didier Puaux
- Division of the Technical and Scientific Police (DTSP), Central Direction of the Judicial Police, Central Service of the Judicial Identity, Forensic Section, 31 Avenue Franklin Roosevelt, F-69134, Ecully, Cedex, France
| | - Rémi Gervais
- Centre de Recherche en Neurosciences de Lyon— UMR CNRS 5292 — INSERM U 1028 — Université Claude Bernard Lyon 1, Université de Lyon, 50 avenue Tony Garnier, F-69366, Lyon, France
| | - Barbara Ferry
- Centre de Recherche en Neurosciences de Lyon— UMR CNRS 5292 — INSERM U 1028 — Université Claude Bernard Lyon 1, Université de Lyon, 50 avenue Tony Garnier, F-69366, Lyon, France
- * E-mail:
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de March CA, Ryu S, Sicard G, Moon C, Golebiowski J. Structure-odour relationships reviewed in the postgenomic era. FLAVOUR FRAG J 2015. [DOI: 10.1002/ffj.3249] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Claire A. de March
- Institut de Chimie de Nice; Université Nice Sophia Antipolis; UMR CNRS 7272, parc Valrose 06108 Nice cedex 02 France
| | - SangEun Ryu
- Laboratory of Chemical Senses, Department of Brain and Cognitive Science; DGIST (Daegu Gyeongbuk Institute of Science & Technology); 50-1 Sang-Ri, Hyeonpung-Myeon, Dalseong-Gun Daegu 711-873 Korea
| | - Gilles Sicard
- Neurobiology of Cellular Interactions and Neurophysiopathology; Aix-Marseille Université; UMR CNRS 7259 13331 Marseille cedex 03 France
| | - Cheil Moon
- Laboratory of Chemical Senses, Department of Brain and Cognitive Science; DGIST (Daegu Gyeongbuk Institute of Science & Technology); 50-1 Sang-Ri, Hyeonpung-Myeon, Dalseong-Gun Daegu 711-873 Korea
| | - Jérôme Golebiowski
- Institut de Chimie de Nice; Université Nice Sophia Antipolis; UMR CNRS 7272, parc Valrose 06108 Nice cedex 02 France
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34
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Perez M, Giurfa M, d'Ettorre P. The scent of mixtures: rules of odour processing in ants. Sci Rep 2015; 5:8659. [PMID: 25726692 PMCID: PMC4345350 DOI: 10.1038/srep08659] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 01/29/2015] [Indexed: 11/08/2022] Open
Abstract
Natural odours are complex blends of numerous components. Understanding how animals perceive odour mixtures is central to multiple disciplines. Here we focused on carpenter ants, which rely on odours in various behavioural contexts. We studied overshadowing, a phenomenon that occurs when animals having learnt a binary mixture respond less to one component than to the other, and less than when this component was learnt alone. Ants were trained individually with alcohols and aldehydes varying in carbon-chain length, either as single odours or binary mixtures. They were then tested with the mixture and the components. Overshadowing resulted from the interaction between chain length and functional group: alcohols overshadowed aldehydes, and longer chain lengths overshadowed shorter ones; yet, combinations of these factors could cancel each other and suppress overshadowing. Our results show how ants treat binary olfactory mixtures and set the basis for predictive analyses of odour perception in insects.
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Affiliation(s)
- Margot Perez
- Research Center on Animal Cognition; University of Toulouse; UPS; 118 route de Narbonne, F-31062 Toulouse Cedex 9, France
- Research Center on Animal Cognition; CNRS; 118 route de Narbonne, F-31062 Toulouse Cedex 9, France
- Laboratory of Experimental and Comparative Ethology, University Paris 13, Sorbonne Paris Cité, Villetaneuse, France
| | - Martin Giurfa
- Research Center on Animal Cognition; University of Toulouse; UPS; 118 route de Narbonne, F-31062 Toulouse Cedex 9, France
- Research Center on Animal Cognition; CNRS; 118 route de Narbonne, F-31062 Toulouse Cedex 9, France
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, University Paris 13, Sorbonne Paris Cité, Villetaneuse, France
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Thomas-Danguin T, Sinding C, Romagny S, El Mountassir F, Atanasova B, Le Berre E, Le Bon AM, Coureaud G. The perception of odor objects in everyday life: a review on the processing of odor mixtures. Front Psychol 2014; 5:504. [PMID: 24917831 PMCID: PMC4040494 DOI: 10.3389/fpsyg.2014.00504] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/08/2014] [Indexed: 11/13/2022] Open
Abstract
Smelling monomolecular odors hardly ever occurs in everyday life, and the daily functioning of the sense of smell relies primarily on the processing of complex mixtures of volatiles that are present in the environment (e.g., emanating from food or conspecifics). Such processing allows for the instantaneous recognition and categorization of smells and also for the discrimination of odors among others to extract relevant information and to adapt efficiently in different contexts. The neurophysiological mechanisms underpinning this highly efficient analysis of complex mixtures of odorants is beginning to be unraveled and support the idea that olfaction, as vision and audition, relies on odor-objects encoding. This configural processing of odor mixtures, which is empirically subject to important applications in our societies (e.g., the art of perfumers, flavorists, and wine makers), has been scientifically studied only during the last decades. This processing depends on many individual factors, among which are the developmental stage, lifestyle, physiological and mood state, and cognitive skills; this processing also presents striking similarities between species. The present review gathers the recent findings, as observed in animals, healthy subjects, and/or individuals with affective disorders, supporting the perception of complex odor stimuli as odor objects. It also discusses peripheral to central processing, and cognitive and behavioral significance. Finally, this review highlights that the study of odor mixtures is an original window allowing for the investigation of daily olfaction and emphasizes the need for knowledge about the underlying biological processes, which appear to be crucial for our representation and adaptation to the chemical environment.
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Affiliation(s)
- Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Charlotte Sinding
- Smell and Taste Clinic, Department of Otorhinolaryngoly TU Dresden, Dresden, Germany
| | - Sébastien Romagny
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Fouzia El Mountassir
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | | | | | - Anne-Marie Le Bon
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Gérard Coureaud
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
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36
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Schütze M, Negoias S, Olsson M, Hummel T. Perceptual and processing differences between physical and dichorhinic odor mixtures. Neuroscience 2014; 258:84-9. [DOI: 10.1016/j.neuroscience.2013.10.079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 10/31/2013] [Accepted: 10/31/2013] [Indexed: 10/26/2022]
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Lytra G, Tempere S, Le Floch A, de Revel G, Barbe JC. Study of sensory interactions among red wine fruity esters in a model solution. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:8504-8513. [PMID: 23984708 DOI: 10.1021/jf4018405] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Our study focused on the impact of 12 red wine esters, in complex mixtures, on the perception of fruity aromas. Aromatic reconstructions were prepared in dilute alcohol solution at the average concentrations found in red wines, using pure commercial products. The impact of ethyl propanoate, ethyl-3-hydroxybutanoate, butyl acetate, and 2-methylpropyl acetate was detected by omission tests, although they were present at subthreshold concentrations in the fruity mixture. The "olfactory threshold" of the fruity pool, consisting of all of the esters excluding ethyl propanoate, ethyl-3-hydroxybutanoate, butyl acetate, or 2-methylpropyl acetate was calculated in two different matrices: dilute alcohol solution and dilute alcohol solution supplemented with each of the four compounds mentioned above. The presence of ethyl-3-hydroxybutanoate and 2-methylpropyl acetate in the mixture led to a significant decrease in the olfactory threshold of the fruity pool, demonstrating their synergistic effect in increasing the overall intensity. Sensory profiles revealed that besides ethyl-3-hydroxybutanoate, the omission of each of these compounds had a significant attenuating effect on blackberry and fresh-fruit aroma intensity. These compounds with similar chemical structures participate, both quantitatively and qualitatively, in modulating fruity aromas and, specifically, naturally enhancing blackberry and fresh-fruit aromas.
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Affiliation(s)
- Georgia Lytra
- Univ. of Bordeaux , ISVV, EA 4577 Œnologie, F-33140 Villenave d'Ornon, France
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Rospars JP, Sanda P, Lansky P, Duchamp-Viret P. Responses of single neurons and neuronal ensembles in frog first- and second-order olfactory neurons. Brain Res 2013; 1536:144-58. [PMID: 23688543 DOI: 10.1016/j.brainres.2013.05.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 05/06/2013] [Accepted: 05/08/2013] [Indexed: 11/17/2022]
Abstract
A major challenge in sensory neuroscience is to elucidate the coding and processing of stimulus representations in successive populations of neurons. Here we recorded the spiking activity of receptor neurons (RNs) and mitral/tufted cells (MCs) in the frog olfactory epithelium and olfactory bulb respectively, in response to four odorants applied at precisely controlled concentrations. We compared how RN responses are translated in MCs. We examined the time course of the instantaneous firing frequency before and after stimulation in neuron ensembles and the dependency on odorant concentration of the number of action potentials fired in a preselected 5-s time window (dose-response curves) in both single neurons and neuron ensembles. In RNs and MCs, the dose-response curves typically increase then decrease and are well described by alpha functions. We established the main quantitative properties of these curves, including the distributions of concentrations at threshold and maximum responses. We showed that the main transformations occurring in the transition from RNs to MCs is the lowering of the firing threshold and a large decrease in the total number of spikes fired. We also found that the number of action potentials fired by recorded neurons and hence their energy consumption is independent of odorant concentration, and that this is a consequence of their time- and concentration-dependent activities. This article is part of a Special Issue entitled Neural Coding 2012.
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Affiliation(s)
- Jean-Pierre Rospars
- UMR 1272 Physiologie de l'Insecte: Signalisation et Communication & Unité Mathématiques et Informatique Appliquées, INRA, F-78000 Versailles, France.
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39
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Rospars JP. Interactions of odorants with olfactory receptors and other preprocessing mechanisms: how complex and difficult to predict? Chem Senses 2013; 38:283-7. [PMID: 23386560 DOI: 10.1093/chemse/bjt004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In this issue of Chemical Senses, Münch et al. present a thorough analysis of how mixtures of odorants interact with olfactory receptors (ORs) borne by olfactory receptor neurons (ORNs). Using fruit fly ORNs expressing the receptor OR22a, they provide a clear example of mixture interaction and confirm that the response of an ORN to a binary mixture can be sometimes predicted quantitatively knowing the ORN responses to its components as shown previously in rat ORNs. The prediction is based on a nonlinear model that assumes a classical 2-step activation of the OR and competition of the 2 odorants in the mixture for the same binding site. Can this success be generalized to all odorant-receptor pairs? This would be an encouraging perspective, especially for the fragrance and flavor industries, as it would permit the prediction of all mixtures. To address this question, I outline its conceptual framework and discuss the variety of mixture interactions found so far. In accordance with the effects described in the study of other receptors, several kinds of mixture interactions have been found that are not easily predictable. The relative importance of the predictable and less predictable effects thus appears as a major issue for future developments.
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Affiliation(s)
- Jean-Pierre Rospars
- UMR 1272 Physiologie de l'Insecte: Signalisation et Communication & Unité Mathématiques et Informatique Appliquées, INRA, F-78000 Versailles, France.
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40
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Neural coding of binary mixtures in a structurally related odorant pair. Sci Rep 2013; 3:1220. [PMID: 23386975 PMCID: PMC3564033 DOI: 10.1038/srep01220] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/17/2013] [Indexed: 11/09/2022] Open
Abstract
The encoding of odorant mixtures by olfactory sensory neurons depends on molecular interactions at peripheral receptors. However, the pharmacological basis of these interactions is not well defined. Both competitive and noncompetitive mechanisms of receptor binding and activation, or suppression, could contribute to coding. We studied this by analyzing responses of olfactory bulb glomeruli evoked by a pair of structurally related odorants, eugenol (EG) and methyl isoeugenol (MIEG). Fluorescence imaging in synaptopHluorin (spH) mice revealed that EG and MIEG evoked highly overlapped glomerular inputs, increasing the likelihood of mixture interactions. Glomerular responses to binary mixtures of EG and MIEG mostly showed hypoadditive interactions at intermediate and high odorant concentrations, with a few near threshold responses showing hyperadditivity. Dose-response profiles were well fitted by a model of two odorants competitively binding and activating a shared receptor linked to a non-linear transduction cascade. We saw no evidence of non-competitive mechanisms.
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Münch D, Schmeichel B, Silbering AF, Galizia CG. Weaker ligands can dominate an odor blend due to syntopic interactions. Chem Senses 2013; 38:293-304. [PMID: 23315042 PMCID: PMC3629874 DOI: 10.1093/chemse/bjs138] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Most odors in natural environments are mixtures of several compounds. Perceptually, these can blend into a new "perfume," or some components may dominate as elements of the mixture. In order to understand such mixture interactions, it is necessary to study the events at the olfactory periphery, down to the level of single-odorant receptor cells. Does a strong ligand present at a low concentration outweigh the effect of weak ligands present at high concentrations? We used the fruit fly receptor dOr22a and a banana-like odor mixture as a model system. We show that an intermediate ligand at an intermediate concentration alone elicits the neuron's blend response, despite the presence of both weaker ligands at higher concentration, and of better ligands at lower concentration in the mixture. Because all of these components, when given alone, elicited significant responses, this reveals specific mixture processing already at the periphery. By measuring complete dose-response curves we show that these mixture effects can be fully explained by a model of syntopic interaction at a single-receptor binding site. Our data have important implications for how odor mixtures are processed in general, and what preprocessing occurs before the information reaches the brain.
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Affiliation(s)
- Daniel Münch
- Neurobiology, University of Konstanz, D-78457 Konstanz, Germany.
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