1
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Schaefer S, Ziegler F, Lang T, Steuer A, Di Pizio A, Behrens M. Membrane-bound chemoreception of bitter bile acids and peptides is mediated by the same subset of bitter taste receptors. Cell Mol Life Sci 2024; 81:217. [PMID: 38748186 PMCID: PMC11096235 DOI: 10.1007/s00018-024-05202-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 05/18/2024]
Abstract
The vertebrate sense of taste allows rapid assessment of the nutritional quality and potential presence of harmful substances prior to ingestion. Among the five basic taste qualities, salty, sour, sweet, umami, and bitter, bitterness is associated with the presence of putative toxic substances and elicits rejection behaviors in a wide range of animals including humans. However, not all bitter substances are harmful, some are thought to be health-beneficial and nutritious. Among those compound classes that elicit a bitter taste although being non-toxic and partly even essential for humans are bitter peptides and L-amino acids. Using functional heterologous expression assays, we observed that the 5 dominant human bitter taste receptors responsive to bitter peptides and amino acids are activated by bile acids, which are notorious for their extreme bitterness. We further demonstrate that the cross-reactivity of bitter taste receptors for these two different compound classes is evolutionary conserved and can be traced back to the amphibian lineage. Moreover, we show that the cross-detection by some receptors relies on "structural mimicry" between the very bitter peptide L-Trp-Trp-Trp and bile acids, whereas other receptors exhibit a phylogenetic conservation of this trait. As some bile acid-sensitive bitter taste receptor genes fulfill dual-roles in gustatory and non-gustatory systems, we suggest that the phylogenetic conservation of the rather surprising cross-detection of the two substance classes could rely on a gene-sharing-like mechanism in which the non-gustatory function accounts for the bitter taste response to amino acids and peptides.
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Affiliation(s)
- Silvia Schaefer
- TUM Graduate School, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany
| | - Florian Ziegler
- TUM Graduate School, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany
| | - Tatjana Lang
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany
| | - Alexandra Steuer
- TUM Graduate School, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Alte Akademie 8, 85354, Freising, Germany
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany
| | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany
- Chemoinformatics and Protein Modelling, Technical University of Munich, Freising, Germany
| | - Maik Behrens
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Lise-Meitner-Strasse 34, 85354, Freising, Germany.
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2
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Kumar P, Behrens M. Influence of Sodium Chloride on Human Bitter Taste Receptor Responses. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10531-10536. [PMID: 38663860 PMCID: PMC11082923 DOI: 10.1021/acs.jafc.3c08775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/08/2024] [Accepted: 04/08/2024] [Indexed: 05/09/2024]
Abstract
In the past, taste interactions between sodium chloride (NaCl) and bitter tastants were investigated in human sensory studies, and the suppression of bitterness by sodium was observed. It is currently not clear if this phenomenon occurs predominantly peripherally or centrally and if the effect is general or only particular bitter compounds are blocked. Therefore, the influence of NaCl at the receptor level was tested by functional expression assays using four out of ∼25 human bitter taste receptors together with prototypical agonists. It was observed that NaCl affected only the responses of particular bitter taste receptor-compound pairs, whereas other bitter responses remained unchanged upon variations of the sodium concentrations. Among the tested receptors, TAS2R16 showed a reduction in signaling in the presence of NaCl. This demonstrates that for some receptor-agonist pairs, NaCl reduces the activation at the receptor level, whereas central effects may dominate the NaCl-induced bitter taste inhibition for other substances.
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Affiliation(s)
- Praveen Kumar
- Leibniz Institute for Food
Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
| | - Maik Behrens
- Leibniz Institute for Food
Systems Biology at the Technical University of Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
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3
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Itoigawa A, Toda Y, Kuraku S, Ishimaru Y. Evolutionary origins of bitter taste receptors in jawed vertebrates. Curr Biol 2024; 34:R271-R272. [PMID: 38593768 DOI: 10.1016/j.cub.2024.02.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 02/08/2024] [Accepted: 02/13/2024] [Indexed: 04/11/2024]
Abstract
Taste is a sense that detects information about nutrients and toxins in foods. Of the five basic taste qualities, bitterness is associated with the detection of potentially harmful substances like plant alkaloids. In bony vertebrates, type 2 taste receptors (T2Rs), which are G-protein-coupled receptors (GPCRs), act as bitter taste receptors1,2. In vertebrates, six GPCR gene families are described as chemosensory receptor genes, encoding taste receptor families (T1Rs and T2Rs) and olfactory receptor families (ORs, V1Rs, V2Rs, and TAARs). These families of receptors have been found in all major jawed vertebrate lineages, except for the T2Rs, which are confined to bony vertebrates3. Therefore, T2Rs are believed to have emerged later than the other chemosensory receptor genes in the bony vertebrate lineage. So far, only the genomes of two cartilaginous fish species have been mined for TAS2R genes, which encode T2Rs4. Here, we identified novel T2Rs in elasmobranchs, namely selachimorphs (sharks) and batoids (rays, skates, and their close relatives) by an exhaustive search covering diverse cartilaginous fishes. Using functional and mRNA expression analyses, we demonstrate that their T2Rs are expressed in the oral taste buds and contribute to the detection of bitter compounds. This finding indicates the early origin of T2Rs in the common ancestor of jawed vertebrates.
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Affiliation(s)
- Akihiro Itoigawa
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan; Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Yasuka Toda
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Shigehiro Kuraku
- Molecular Life History Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, SOKENDAI (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Yoshiro Ishimaru
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan.
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4
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Policarpo M, Baldwin MW, Casane D, Salzburger W. Diversity and evolution of the vertebrate chemoreceptor gene repertoire. Nat Commun 2024; 15:1421. [PMID: 38360851 PMCID: PMC10869828 DOI: 10.1038/s41467-024-45500-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
Chemoreception - the ability to smell and taste - is an essential sensory modality of most animals. The number and type of chemical stimuli that animals can perceive depends primarily on the diversity of chemoreceptors they possess and express. In vertebrates, six families of G protein-coupled receptors form the core of their chemosensory system, the olfactory/pheromone receptor gene families OR, TAAR, V1R and V2R, and the taste receptors T1R and T2R. Here, we study the vertebrate chemoreceptor gene repertoire and its evolutionary history. Through the examination of 1,527 vertebrate genomes, we uncover substantial differences in the number and composition of chemoreceptors across vertebrates. We show that the chemoreceptor gene families are co-evolving, highly dynamic, and characterized by lineage-specific expansions (for example, OR in tetrapods; TAAR, T1R in teleosts; V1R in mammals; V2R, T2R in amphibians) and losses. Overall, amphibians, followed by mammals, are the vertebrate clades with the largest chemoreceptor repertoires. While marine tetrapods feature a convergent reduction of chemoreceptor numbers, the number of OR genes correlates with habitat in mammals and birds and with migratory behavior in birds, and the taste receptor repertoire correlates with diet in mammals and with aquatic environment in fish.
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Affiliation(s)
- Maxime Policarpo
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
| | - Maude W Baldwin
- Evolution of Sensory Systems Research Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany
| | - Didier Casane
- Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, Gif-sur-Yvette, France
- Université Paris Cité, UFR Sciences du Vivant, Paris, France
| | - Walter Salzburger
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
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5
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Lennox-Bulow D, Smout M, Loukas A, Seymour J. Stonefish (Synanceia spp.) Ichthyocrinotoxins: An ecological review and prospectus for future research and biodiscovery. Toxicon 2023; 236:107329. [PMID: 37907137 DOI: 10.1016/j.toxicon.2023.107329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 09/20/2023] [Accepted: 09/30/2023] [Indexed: 11/02/2023]
Abstract
Marine organisms possess a diverse array of unique substances, many with wide ranging potential for applications in medicine, industry, and other sectors. Stonefish (Synanceia spp.), a bottom-dwelling fish that inhabit shallow and intertidal waters throughout the Indo-Pacific, harbour two distinct substances, a venom, and an ichthyocrinotoxin. Stonefish are well-known for the potent venom associated with their dorsal spines as it poses a significant risk to public health. Consequently, much of the research on stonefish focusses on the venom, with the aim of improving outcomes in cases of envenomation. However, there has been a notable lack of research on stonefish ichthyocrinotoxins, a class of toxin that is synthesised within specialised epithelial cells (i.e., tubercles) and exuded onto the skin. This has resulted in a substantial knowledge gap in our understanding of these animals. This review aims to bridge this gap by consolidating literature on the ecological functions and biochemical attributes of ichthyocrinotoxins present in various fish species and juxtaposing it with the current state of knowledge of stonefish ecology. We highlight the roles of ichthyocrinotoxins in predator defence, bolstering innate immunity, and mitigating integumentary interactions with parasites and detrimental fouling organisms. The objective of this review is to identify promising research avenues that could shed light on the ecological functions of stonefish ichthyocrinotoxins and their potential practical applications as therapeutics and/or industrial products.
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Affiliation(s)
- Danica Lennox-Bulow
- Tropical Australian Stinger Research Unit, James Cook University, McGregor Road, Cairns, Queensland, Australia; Australian Institute of Tropical Health and Medicine (AITHM), James Cook University, McGregor Road, Cairns, Queensland, Australia.
| | - Michael Smout
- Australian Institute of Tropical Health and Medicine (AITHM), James Cook University, McGregor Road, Cairns, Queensland, Australia
| | - Alex Loukas
- Australian Institute of Tropical Health and Medicine (AITHM), James Cook University, McGregor Road, Cairns, Queensland, Australia
| | - Jamie Seymour
- Tropical Australian Stinger Research Unit, James Cook University, McGregor Road, Cairns, Queensland, Australia; Australian Institute of Tropical Health and Medicine (AITHM), James Cook University, McGregor Road, Cairns, Queensland, Australia
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6
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Behrens M, Lang T, Korsching SI. A singular shark bitter taste receptor provides insights into the evolution of bitter taste perception. Proc Natl Acad Sci U S A 2023; 120:e2310347120. [PMID: 37956436 PMCID: PMC10691231 DOI: 10.1073/pnas.2310347120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/05/2023] [Indexed: 11/15/2023] Open
Abstract
Many animal and plant species synthesize toxic compounds as deterrent; thus, detection of these compounds is of vital importance to avoid their ingestion. Often, such compounds are recognized by taste 2 receptors that mediate bitter taste in humans. Until now, bitter taste receptors have only been found in bony vertebrates, where they occur as a large family already in coelacanth, a "living fossil" and the earliest-diverging extant lobe-finned fish. Here, we have revisited the evolutionary origin of taste 2 receptors (T2Rs) making use of a multitude of recently available cartilaginous fish genomes. We have identified a singular T2R in 12 cartilaginous fish species (9 sharks, 1 sawfish, and 2 skates), which represents a sister clade to all bony fish T2Rs. We have examined its ligands for two shark species, a catshark and a bamboo shark. The ligand repertoire of bamboo shark represents a subset of that of the catshark, with roughly similar thresholds. Amarogentin, one of the most bitter natural substances for humans, also elicited the highest signal amplitudes with both shark receptors. Other subsets of ligands are shared with basal bony fish T2Rs indicating an astonishing degree of functional conservation over nearly 500 mya of separate evolution. Both shark receptors respond to endogenous steroids as well as xenobiotic compounds, whereas separate receptors exist for xenobiotics both in early- and late-derived bony vertebrates (coelacanth, zebrafish, and human), consistent with the shark T2R reflecting the original ligand repertoire of the ancestral bitter taste receptor at the evolutionary origin of this family.
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Affiliation(s)
- Maik Behrens
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising85354, Germany
| | - Tatjana Lang
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising85354, Germany
| | - Sigrun I. Korsching
- Institute of Genetics, Faculty of Mathematics and Natural Sciences, University at Cologne, Cologne50674, Germany
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7
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Mao J, Cao Y, Zhang Y, Huang B, Zhao Y. A novel method for identifying key genes in macroevolution based on deep learning with attention mechanism. Sci Rep 2023; 13:19727. [PMID: 37957311 PMCID: PMC10643560 DOI: 10.1038/s41598-023-47113-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 11/09/2023] [Indexed: 11/15/2023] Open
Abstract
Macroevolution can be regarded as the result of evolutionary changes of synergistically acting genes. Unfortunately, the importance of these genes in macroevolution is difficult to assess and hence the identification of macroevolutionary key genes is a major challenge in evolutionary biology. In this study, we designed various word embedding libraries of natural language processing (NLP) considering the multiple mechanisms of evolutionary genomics. A novel method (IKGM) based on three types of attention mechanisms (domain attention, kmer attention and fused attention) were proposed to calculate the weights of different genes in macroevolution. Taking 34 species of diurnal butterflies and nocturnal moths in Lepidoptera as an example, we identified a few of key genes with high weights, which annotated to the functions of circadian rhythms, sensory organs, as well as behavioral habits etc. This study not only provides a novel method to identify the key genes of macroevolution at the genomic level, but also helps us to understand the microevolution mechanisms of diurnal butterflies and nocturnal moths in Lepidoptera.
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Affiliation(s)
- Jiawei Mao
- College of Big Data and Intelligent Engineering, Southwest Forestry University, Kunming, 650224, China
| | - Yong Cao
- College of Big Data and Intelligent Engineering, Southwest Forestry University, Kunming, 650224, China
| | - Yan Zhang
- College of Mathematics and Physics, Southwest Forestry University, Kunming, 650224, China
| | - Biaosheng Huang
- College of Big Data and Intelligent Engineering, Southwest Forestry University, Kunming, 650224, China
| | - Youjie Zhao
- College of Big Data and Intelligent Engineering, Southwest Forestry University, Kunming, 650224, China.
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8
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Kumar P, Redel U, Lang T, Korsching SI, Behrens M. Bitter taste receptors of the zebra finch ( Taeniopygia guttata). Front Physiol 2023; 14:1233711. [PMID: 37860623 PMCID: PMC10582322 DOI: 10.3389/fphys.2023.1233711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/20/2023] [Indexed: 10/21/2023] Open
Abstract
Despite the important role of bitter taste for the rejection of potentially harmful food sources, birds have long been suspected to exhibit inferior bitter tasting abilities. Although more recent reports on the bitter recognition spectra of several bird species have cast doubt about the validity of this assumption, the bitter taste of avian species is still an understudied field. Previously, we reported the bitter activation profiles of three zebra finch receptors Tas2r5, -r6, and -r7, which represent orthologs of a single chicken bitter taste receptor, Tas2r1. In order to get a better understanding of the bitter tasting capabilities of zebra finches, we selected another Tas2r gene of this species that is similar to another chicken Tas2r. Using functional calcium mobilization experiments, we screened zebra finch Tas2r1 with 72 bitter compounds and observed responses for 7 substances. Interestingly, all but one of the newly identified bitter agonists were different from those previously identified for Tas2r5, -r6, and -r7 suggesting that the newly investigated receptor fills important gaps in the zebra finch bitter recognition profile. The most potent bitter agonist found in our study is cucurbitacin I, a highly toxic natural bitter substance. We conclude that zebra finch exhibits an exquisitely developed bitter taste with pronounced cucurbitacin I sensitivity suggesting a prominent ecological role of this compound for zebra finch.
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Affiliation(s)
- Praveen Kumar
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Ulrike Redel
- German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Tatjana Lang
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | | | - Maik Behrens
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
- German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
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9
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Ziegler F, Steuer A, Di Pizio A, Behrens M. Physiological activation of human and mouse bitter taste receptors by bile acids. Commun Biol 2023; 6:612. [PMID: 37286811 DOI: 10.1038/s42003-023-04971-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 05/23/2023] [Indexed: 06/09/2023] Open
Abstract
Beside the oral cavity, bitter taste receptors are expressed in several non-gustatory tissues. Whether extra-oral bitter taste receptors function as sensors for endogenous agonists is unknown. To address this question, we devised functional experiments combined with molecular modeling approaches to investigate human and mouse receptors using a variety of bile acids as candidate agonists. We show that five human and six mouse receptors are responsive to an array of bile acids. Moreover, their activation threshold concentrations match published data of bile acid concentrations in human body fluids, suggesting a putative physiological activation of non-gustatory bitter receptors. We conclude that these receptors could serve as sensors for endogenous bile acid levels. These results also indicate that bitter receptor evolution may not be driven solely by foodstuff or xenobiotic stimuli, but also depend on endogenous ligands. The determined bitter receptor activation profiles of bile acids now enable detailed physiological model studies.
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Affiliation(s)
- Florian Ziegler
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Alexandra Steuer
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Antonella Di Pizio
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Maik Behrens
- Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany.
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10
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Abstract
Vertebrate Tas2r taste receptors detect bitter compounds that are potentially poisonous. Previous studies found substantial variation in the number of Tas2r genes across vertebrates, with some frog species carrying the largest number. Peculiar among vertebrates, frogs undergo metamorphosis, often associated with a dietary shift between tadpoles and adults. A possible explanation for the large size of frog Tas2r families could be that distinct sets of Tas2r genes are required for tadpoles and adults, suggesting differential expression of Tas2r genes between tadpoles and adults. To test this hypothesis, we first examined 20 amphibian genomes and found that amphibians generally possess more Tas2r genes than do other vertebrate clades. We next focused on the American bullfrog (Lithobates catesbeianus) to examine the expression of its Tas2r genes in herbivorous tadpoles and insectivorous adult frogs. We report that close to one fifth of its 180 Tas2r genes are differentially expressed (22 genes enriched in adults and 11 in tadpoles). Tuning properties were determined for a subset of differentially expressed genes by a cell-based functional assay, with the adult-enriched Tas2r gene set covering a larger range of ligands compared to the tadpole-enriched subset. These results suggest a role of Tas2r genes in the ontogenetic dietary shift of frogs and potentially initiate a new avenue of ontogenetic analysis of diet-related genes in the animal kingdom.
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11
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Birdal G, D'Gama PP, Jurisch-Yaksi N, Korsching SI. Expression of taste sentinels, T1R, T2R, and PLCβ2, on the passageway for olfactory signals in zebrafish. Chem Senses 2023; 48:bjad040. [PMID: 37843175 DOI: 10.1093/chemse/bjad040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Indexed: 10/17/2023] Open
Abstract
The senses of taste and smell detect overlapping sets of chemical compounds in fish, e.g. amino acids are detected by both senses. However, so far taste and smell organs appeared morphologically to be very distinct, with a specialized olfactory epithelium for detection of odors and taste buds located in the oral cavity and lip for detection of tastants. Here, we report dense clusters of cells expressing T1R and T2R receptors as well as their signal transduction molecule PLCβ2 in nostrils of zebrafish, i.e. on the entrance funnel through which odor molecules must pass to be detected by olfactory sensory neurons. Quantitative evaluation shows the density of these chemosensory cells in the nostrils to be as high or higher than that in the established taste organs oral cavity and lower lip. Hydrodynamic flow is maximal at the nostril rim enabling high throughput chemosensation in this organ. Taken together, our results suggest a sentinel function for these chemosensory cells in the nostril.
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Affiliation(s)
- Günes Birdal
- Institute for Genetics, Department of Biology, University of Cologne, Zülpicher Str. 47A, 50674 Cologne, Germany
| | - Percival P D'Gama
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skjalgsons Gate 1, 7491 Trondheim, Norway
| | - Nathalie Jurisch-Yaksi
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Erling Skjalgsons Gate 1, 7491 Trondheim, Norway
| | - Sigrun I Korsching
- Institute for Genetics, Department of Biology, University of Cologne, Zülpicher Str. 47A, 50674 Cologne, Germany
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12
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Itoigawa A, Hayakawa T, Zhou Y, Manning AD, Zhang G, Grutzner F, Imai H. Functional Diversity and Evolution of Bitter Taste Receptors in Egg-Laying Mammals. Mol Biol Evol 2022; 39:6591311. [PMID: 35652727 PMCID: PMC9161717 DOI: 10.1093/molbev/msac107] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Egg-laying mammals (monotremes) are a sister clade of therians (placental mammals and marsupials) and a key clade to understand mammalian evolution. They are classified into platypus and echidna, which exhibit distinct ecological features such as habitats and diet. Chemosensory genes, which encode sensory receptors for taste and smell, are believed to adapt to the individual habitats and diet of each mammal. In this study, we focused on the molecular evolution of bitter taste receptors (TAS2Rs) in monotremes. The sense of bitter taste is important to detect potentially harmful substances. We comprehensively surveyed agonists of all TAS2Rs in platypus (Ornithorhynchus anatinus) and short-beaked echidna (Tachyglossus aculeatus) and compared their functions with orthologous TAS2Rs of marsupial and placental mammals (i.e., therians). As results, the agonist screening revealed that the deorphanized monotreme receptors were functionally diversified. Platypus TAS2Rs had broader receptive ranges of agonists than those of echidna TAS2Rs. While platypus consumes a variety of aquatic invertebrates, echidna mainly consumes subterranean social insects (ants and termites) as well as other invertebrates. This result indicates that receptive ranges of TAS2Rs could be associated with feeding habits in monotremes. Furthermore, some orthologous receptors in monotremes and therians responded to β-glucosides, which are feeding deterrents in plants and insects. These results suggest that the ability to detect β-glucosides and other substances might be shared and ancestral among mammals.
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Affiliation(s)
- Akihiro Itoigawa
- Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan.,Department of Agricultural Chemistry, School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan
| | - Takashi Hayakawa
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan.,Japan Monkey Centre, Inuyama, Aichi, Japan
| | | | - Adrian D Manning
- Fenner School of Environment and Society, The Australian National University, Canberra, ACT, Australia
| | - Guojie Zhang
- Department of Biology, University of Copenhagen, Kobenhavn, Denmark
| | - Frank Grutzner
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Hiroo Imai
- Molecular Biology Section, Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Aichi, Japan
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13
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Bhatia V, de Jesus VC, Shaik FA, Jaggupilli A, Singh N, Chelikani P, Atukorallaya D. Extraoral expression and characterization of bitter taste receptors in
Astyanax mexicanus
(Mexican Tetra Fish). FASEB Bioadv 2022; 4:574-584. [PMID: 36089978 PMCID: PMC9447421 DOI: 10.1096/fba.2022-00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Vikram Bhatia
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Vivianne Cruz de Jesus
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Feroz Ahmed Shaik
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Nisha Singh
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
| | - Devi Atukorallaya
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology University of Manitoba Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2 Canada
- Children’s Hospital Research Institute of Manitoba (CHRIM), Winnipeg MB R3E3P4 Canada
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14
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Wooding SP, Ramirez VA, Behrens M. Bitter taste receptors: Genes, evolution and health. Evol Med Public Health 2022; 9:431-447. [PMID: 35154779 PMCID: PMC8830313 DOI: 10.1093/emph/eoab031] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/05/2021] [Indexed: 02/01/2023] Open
Abstract
Bitter taste perception plays vital roles in animal behavior and fitness. By signaling the presence of toxins in foods, particularly noxious defense compounds found in plants, it enables animals to avoid exposure. In vertebrates, bitter perception is initiated by TAS2Rs, a family of G protein-coupled receptors expressed on the surface of taste buds. There, oriented toward the interior of the mouth, they monitor the contents of foods, drinks and other substances as they are ingested. When bitter compounds are encountered, TAS2Rs respond by triggering neural pathways leading to sensation. The importance of this role placed TAS2Rs under selective pressures in the course of their evolution, leaving signatures in patterns of gene gain and loss, sequence polymorphism, and population structure consistent with vertebrates' diverse feeding ecologies. The protective value of bitter taste is reduced in modern humans because contemporary food supplies are safe and abundant. However, this is not always the case. Some crops, particularly in the developing world, retain surprisingly high toxicity and bitterness remains an important measure of safety. Bitter perception also shapes health through its influence on preference driven behaviors such as diet choice, alcohol intake and tobacco use. Further, allelic variation in TAS2Rs is extensive, leading to individual differences in taste sensitivity that drive these behaviors, shaping susceptibility to disease. Thus, bitter taste perception occupies a critical intersection between ancient evolutionary processes and modern human health.
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Affiliation(s)
- Stephen P Wooding
- Department of Anthropology and Health Sciences Research Institute, University of California, Merced, CA, USA
| | - Vicente A Ramirez
- Department of Public Health, University of California, Merced, CA, USA
| | - Maik Behrens
- Maik Behrens, Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
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15
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Wooding SP, Ramirez VA. Worldwide diversity, association potential, and natural selection in the superimposed taste genes, CD36 and GNAT3. Chem Senses 2022; 47:6491270. [PMID: 34972209 DOI: 10.1093/chemse/bjab052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CD36 and GNAT3 mediate taste responses, with CD36 acting as a lipid detector and GNAT3 acting as the α subunit of gustducin, a G protein governing sweet, savory, and bitter transduction. Strikingly, the genes encoding CD36 and GNAT3 are genomically superimposed, with CD36 completely encompassing GNAT3. To characterize genetic variation across the CD36-GNAT3 region, its implications for phenotypic diversity, and its recent evolution, we analyzed from ~2,500 worldwide subjects sequenced by the 1000 Genomes Project (1000GP). CD36-GNAT3 harbored extensive diversity including 8,688 single-nucleotide polymorphisms (SNPs), 414 indels, and other complex variants. Sliding window analyses revealed that nucleotide diversity and population differentiation across CD36-GNAT3 were consistent with genome-wide trends in the 1000GP (π = 0.10%, P = 0.64; FST = 9.0%, P = 0.57). In addition, functional predictions using SIFT and PolyPhen-2 identified 60 variants likely to alter protein function, and they were in weak linkage disequilibrium (r2 < 0.17), suggesting their effects are largely independent. However, the frequencies of predicted functional variants were low (P¯ = 0.0013), indicating their contributions to phenotypic variance on population scales are limited. Tests using Tajima's D statistic revealed that pressures from natural selection have been relaxed across most of CD36-GNAT3 during its recent history (0.39 < P < 0.67). However, CD36 exons showed signs of local adaptation consistent with prior reports (P < 0.035). Thus, CD36 and GNAT3 harbor numerous variants predicted to affect taste sensitivity, but most are rare and phenotypic variance on a population level is likely mediated by a small number of sites.
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Affiliation(s)
- Stephen P Wooding
- Department of Anthropology, University of California, Merced, Merced, CA, USA
| | - Vicente A Ramirez
- Department of Public Health, University of California, Merced, Merced, CA, USA
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16
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Oteiza P, Baldwin MW. Evolution of sensory systems. Curr Opin Neurobiol 2021; 71:52-59. [PMID: 34600187 DOI: 10.1016/j.conb.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/26/2021] [Indexed: 01/14/2023]
Abstract
Sensory systems evolve and enable organisms to perceive their sensory Umwelt, the unique set of cues relevant for their survival. The multiple components that comprise sensory systems - the receptors, cells, organs, and dedicated high-order circuits - can vary greatly across species. Sensory receptor gene families can expand and contract across lineages, resulting in enormous sensory diversity. Comparative studies of sensory receptor function have uncovered the molecular basis of receptor properties and identified novel sensory receptor classes and noncanonical sensory strategies. Phylogenetically informed comparisons of sensory systems across multiple species can pinpoint when sensory changes evolve and highlight the role of contingency in sensory system evolution.
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Affiliation(s)
- Pablo Oteiza
- Flow Sensing Research Group, Max Planck Institute for Ornithology, Seewiesen, Germany.
| | - Maude W Baldwin
- Evolution of Sensory Systems Research Group, Max Planck Institute for Ornithology, Seewiesen, Germany.
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17
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Shimizu T, Kubozono T, Asaoka R, Toda Y, Ishimaru Y. Expression profiles and functional characterization of common carp ( Cyprinus carpio) T2Rs. Biochem Biophys Rep 2021; 28:101123. [PMID: 34504956 PMCID: PMC8416640 DOI: 10.1016/j.bbrep.2021.101123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 08/30/2021] [Indexed: 11/24/2022] Open
Abstract
Bitter taste perception is mediated by a family of G protein-coupled receptors (T2Rs) in vertebrates. Common carp (Cyprinus carpio), which has experienced an additional round of whole genome duplication during the course of evolution, has a small number of T2R genes similar to zebrafish, a closely related cyprinid fish species, and their expression pattern at the cellular level or their cognate ligands have not been elucidated yet. Here, we showed through in situ hybridization experiments, that three common carp T2R (ccT2R) genes encoding ccT2R200-1, ccT2R202-1, and ccT2R202-2, were specifically expressed in the subsets of taste receptor cells in the lips and gill rakers. ccT2R200-1 was co-expressed with genes encoding downstream signal transduction molecules, such as PLC-β2 and Gαia. Heterologous expression system revealed that each ccT2R showed narrowly, intermediately, or broadly tuned ligand specificity, as in the case of zebrafish T2Rs. However, ccT2Rs showed different ligand profiles from their orthologous zebrafish T2Rs previously reported. Finally, we identified three ccT2Rs, namely ccT2R200-1, ccT2R200-2, and ccT2R203-1, to be activated by natural bitter compounds, andrographolide and/or picrotoxinin, which elicited no response to zebrafish T2Rs, in a dose-dependent manner. These results suggest that some ccT2Rs may have evolved to function in the oral cavity as taste receptors for natural bitter compounds found in the habitats in a species-specific manner. Common carp T2R (ccT2R) gene was co-expressed with genes encoding downstream signal transduction molecules in subsets of taste receptor cells, similar to zebrafish. Each ccT2R showed narrowly, intermediately, or broadly tuned ligand specificity, as in the case of zebrafish T2Rs; however, ccT2Rs showed different ligand profiles from their orthologous zebrafish T2Rs previously reported. Some ccT2Rs may have evolved to function in the oral cavity as taste receptors for natural bitter compounds found in the habitats in a species-specific manner.
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Affiliation(s)
- Toshiki Shimizu
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Takashi Kubozono
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Ryota Asaoka
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Yasuka Toda
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Yoshiro Ishimaru
- Department of Agricultural Chemistry, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
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18
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Ziegler F, Behrens M. Bitter taste receptors of the common vampire bat are functional and show conserved responses to metal ions in vitro. Proc Biol Sci 2021; 288:20210418. [PMID: 33784867 DOI: 10.1098/rspb.2021.0418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The bitter taste sensation is important to warn mammals of the ingestion of potentially toxic food compounds. For mammals, whose nutrition relies on highly specific food sources, such as blood in the case of vampire bats, it is unknown if bitter sensing is involved in prey selection. By contrast to other bat species, vampire bats exhibit numerous bitter taste receptor pseudogenes, which could point to a decreased importance of bitter taste. However, electrophysiological and behavioural studies suggest the existence of functional bitter taste transmission. To determine the agonist spectra of the three bitter taste receptors that are conserved in all three vampire bat species, we investigated the in vitro activation of Desmodus rotundus T2R1, T2R4 and T2R7. Using a set of 57 natural and synthetic bitter compounds, we were able to identify agonists for all three receptors. Hence, we confirmed a persisting functionality and, consequently, a putative biological role of bitter taste receptors in vampire bats. Furthermore, the activation of the human TAS2R7 by metal ions is shown to be conserved in D. rotundus.
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Affiliation(s)
- Florian Ziegler
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
| | - Maik Behrens
- Leibniz-Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany
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