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Delicious : the evolution of flavor and how it made us human
\"A savory account of how the pursuit of delicious foods shaped human evolution\"-- Provided by publisher.
BOOK
Sensory adjectives in the discourse of food : a frame-semantic approach to language and perception
Sensory Adjectives in the Discourse of Food presents a frame-based analysis of sensory descriptors. This book investigates the identification and usefulness of conceptual frames in three respects: First, an analysis of scientific language use shows that a semantic interpretation of the adjectives is dependent on the operationalizations performed in the field of sensory science. Second, a systematic frame semantic analysis of the descriptors sheds light on how meaning is constructed with regard to the lexemes' wider context, from the utterance to the text type. Third, a comparison with German descriptors tests the applicability of a frame from one language to another (English - German). Framing presents itself as a means to capture the knowledge representation that underlies a particular discourse. With its detailed linguistic analyses and its interdisciplinary treatment of framing across discourse (specialized vs. public discourse), this book is interesting for researchers working within cognitive linguistics, terminology, and sensory science.
eBook
Taste buds: cells, signals and synapses
Key Points
Taste buds are composed of two excitable cell types and a glia-like cell; each type of cell has distinct functions.
Basic taste qualities are detected by G protein-coupled type 1 and type 2 taste receptors, by other receptors and ion channels, and possibly by transporters.
ATP is an afferent taste transmitter and is secreted by taste bud cells through an unconventional, non-vesicular release mechanism.
ATP, serotonin and GABA mediate cell–cell interactions in the taste bud that may shape transmission to sensory afferent fibres.
Controversy remains regarding whether peripheral taste coding follows a labelled-line or combinatorial pattern.
Taste preferences and appetites seem to have a genetic component that is being revealed by molecular and population studies.
Mammals detect the nutrient content, palatability and potential toxicity of food through taste buds that are present mainly in the tongue. In this Review, Roper and Chaudhari discuss the taste bud cells, receptors and transmitters that are involved in taste detection, how these cells communicate with sensory afferent fibres, and peripheral taste coding.
The past decade has witnessed a consolidation and refinement of the extraordinary progress made in taste research. This Review describes recent advances in our understanding of taste receptors, taste buds, and the connections between taste buds and sensory afferent fibres. The article discusses new findings regarding the cellular mechanisms for detecting tastes, new data on the transmitters involved in taste processing and new studies that address longstanding arguments about taste coding.
Journal Article
An update on extra-oral bitter taste receptors
Bitter taste-sensing type 2 receptors (TAS2Rs or T2Rs), belonging to the subgroup of family A G-protein coupled receptors (GPCRs), are of crucial importance in the perception of bitterness. Although in the first instance, TAS2Rs were considered to be exclusively distributed in the apical microvilli of taste bud cells, numerous studies have detected these sensory receptor proteins in several extra-oral tissues, such as in pancreatic or ovarian tissues, as well as in their corresponding malignancies. Critical points of extra-oral TAS2Rs biology, such as their structure, roles, signaling transduction pathways, extensive mutational polymorphism, and molecular evolution, have been currently broadly studied. The TAS2R cascade, for instance, has been recently considered to be a pivotal modulator of a number of (patho)physiological processes, including adipogenesis or carcinogenesis. The latest advances in taste receptor biology further raise the possibility of utilizing TAS2Rs as a therapeutic target or as an informative index to predict treatment responses in various disorders. Thus, the focus of this review is to provide an update on the expression and molecular basis of TAS2Rs functions in distinct extra-oral tissues in health and disease. We shall also discuss the therapeutic potential of novel TAS2Rs targets, which are appealing due to their ligand selectivity, expression pattern, or pharmacological profiles.
Journal Article
Lgr5.sup.+ ductal cells of von Ebner's glands: Candidate stem cells for turnover of posterior tongue taste buds
Taste bud cells have a limited lifespan and must be continuously replaced along with the papilla epithelium in which they reside. Previous work has shown that expression of leucine-rich G protein-coupled receptor 5 (Lgr5), a Wnt pathway agonist, serves as a marker of adult stem/progenitor cells for taste buds located in posterior tongue (circumvallate and foliate), but not anterior tongue (fungiform), taste papillae. However, the specific location/niche of the Lgr5-expressing cells supporting renewal and their phenotypic properties have not been fully explored. To address this, the genesis and fate of Lgr5.sup.+ cells were examined in developing and adult mice using genetic reporter strains. Evidence from Lgr5-lacZ and Lgr5-GFP mice shows that, while Lgr5 is broadly expressed in the epithelium of nascent circumvallate papillae and their trenches during embryonic development, it becomes concentrated within the ducts of adjacent von Ebner's salivary glands during the first postnatal week, co-incident with the appearance of differentiated taste buds. In posterior tongue taste papillae of adult animals, sites of highest Lgr5-lacZ and Lgr5-GFP expression are found in excretory ducts, restricted to the outer (basal) layer of the bi-layered excretory zone. These Lgr5.sup.+ cells are immunoreactive for keratin 14, like cells in the basal layer of extragemmal taste epithelium, and are often seen to express Sox9, a marker of exocrine gland duct cells. Lineage tracing experiments with an Lgr5-EGFP-IRES-CreERT2; mTmG reporter show that Lgr5.sup.+ ductal cells become labeled one day following Cre induction, prior to the appearance of descendent cells in taste buds. Overall, the data support a role for Lgr5.sup.+ ductal cells as stem cells and suggest that a cooperative interaction exists between posterior taste epithelium and its associated salivary glands in taste cell turnover.
Journal Article
GLP-1 Analog Modulates Appetite, Taste Preference, Gut Hormones, and Regional Body Fat Stores in Adults with Obesity
Abstract
Purpose
Obesity is associated with alterations in appetite, gastrointestinal hormone levels and excessive fat mass. We previously published a double-blind, placebo-controlled, randomized, 16-week trial on effects of once-daily glucagon-like peptide-1 (GLP-1) analog, liraglutide on weight, satiation, and gastric functions in obese volunteers. The aim of this substudy is to compare to placebo the effects of liraglutide on appetite, taste preference, regional body fat stores, and anthropometric measurements.
Methods
Forty obese adults received standard instruction for weight management, monthly behavioral intervention utilizing motivational interviews, and 16-week treatment of once-daily liraglutide (escalated to 3 mg SQ daily). At baseline and 16 weeks, the following were measured: appetite and taste preferences rated every 30 min for 5 h after ingesting 300 mL Ensure®; maximal tolerated volume (MTV) with a nutrient drink test; fasting and postprandial bioactive GLP-1 (7–36) and peptide YY (PYY) levels; total and regional body fat with dual-energy X-ray absorptiometry, and waist and hip circumference.
Results
Thirty-five participants (17 liraglutide; 18 placebo) completed the trial. Compared to placebo group, liraglutide group had significant reductions in MTV; prospective food consumption score; desire to eat something sweet, salty, savory or fatty; and an increase in perceived fullness. Postprandial plasma levels of GLP-1 decreased and PYY levels increased with liraglutide relative to baseline. Significant reductions in total body, trunk, and upper and lower body fat without reduction in lean body mass were observed.
Conclusion
Liraglutide 3 mg SQ modulates appetite, taste preference, gut hormones, and regional body fat stores in adults with obesity without reduction in lean body mass.
Journal Article
Influence of age and sex on taste function of healthy subjects
The purpose of this study was to determine the influence of age and sex on the taste functions of healthy Taiwanese. Subjects were divided into groups based on their sex and age: 20-39 years, 40-59 years, or [greater than or equal to] 60 years. We evaluated the taste functions of subjects using the whole mouth suprathreshold taste test and the taste quad test. For the whole-mouth test, subjects were instructed to sip and swish sweet, sour, salty, and bitter solutions, each at 5 different suprathreshold concentrations. Each subject was required to indicate the taste quality, and to rate the intensity and unpleasantness/pleasantness of each taste of the solutions. For the quad test, the 4 quadrants of the tongue surface were tested by applying a drop of one concentration of sweet, sour, salty, or bitter solutions 6 times. Subjects then indicated the taste quality and rated the intensity of the solution. We found that in the whole mouth test, the total correct identification score dropped with age, but the ability to identify sweet and salty qualities was not affected by age. No differences were found between males and females, except women scored better than men for sweetness in the 40-59 years age group. The intensity rating scores were higher in the 20-39 years age group, regardless of sex. With regard to the pleasantness of tastants, female subjects in the 20-39 years age group found sweet solution more pleasant than the older subjects did. In the quad test, the total correct identification score decreased with age, but there were no differences between males and females. Thus, our findings showed that both age and sex affected the taste functions of healthy Taiwanese to some extent, and differences were dependent on tongue region and taste quality.
Journal Article
Human intestinal bitter taste receptors regulate innate immune responses and metabolic regulators in obesity
Bitter taste receptors (taste 2 receptors, TAS2Rs) serve as warning sensors in the lingual system against the ingestion of potentially poisonous food. Here, we investigated the functional role of TAS2Rs in the human gut and focused on their potential to trigger an additional host defense pathway in the intestine. Human jejunal crypts, especially those from individuals with obesity, responded to bitter agonists by inducing the release of antimicrobial peptides (α-defensin 5 and regenerating islet-derived protein 3 α [REG3A]) but also regulated the expression of other innate immune factors (mucins, chemokines) that affected E. coli growth. We found that the effect of aloin on E. coli growth and on the release of the mucus glycoprotein CLCA1, identified via proteomics, was affected by TAS2R43 deletion polymorphisms and thus confirmed a role for TAS2R43. RNA-Seq revealed that denatonium benzoate induced an NRF2-mediated nutrient stress response and an unfolded protein response that increased the expression of the mitokine GDF15 but also ADM2 and LDLR, genes that are involved in anorectic signaling and lipid homeostasis. In conclusion, TAS2Rs in the intestine constitute a promising target for treating diseases that involve disturbances in the innate immune system and body weight control. TAS2R polymorphisms may be valuable genetic markers to predict therapeutic responses.
Journal Article
CALHM1 ion channel mediates purinergic neurotransmission of sweet, bitter and umami tastes
The voltage-gated ion channel CALHM1 is vital to taste-stimuli-evoked ATP release from sweet-, bitter- and umami-sensing taste bud cells in mice, but does not seem relevant to the recognition of sour and salty tastes.
CALHM1 ATPase mediates three tastes
Perception of sweet, bitter and umami tastes relies on the non-vesicular release from taste bud cells of ATP, which acts as a neurotransmitter to activate the nerves sending gustatory signals to the brain. Now teams led by Kevin Foskett and Philippe Marambaud have used gene-knockout mice to show that the voltage-gated ion channel CALHM1 (calcium homeostasis modulator 1) acts as a voltage-gated ATP-release channel required for sweet, bitter and umami taste perception. CALHM1 deficiency affected taste perception without interfering with taste cell development or integrity, implying that it is a key functional component of the peripheral taste system.
Recognition of sweet, bitter and umami tastes requires the non-vesicular release from taste bud cells of ATP, which acts as a neurotransmitter to activate afferent neural gustatory pathways
1
. However, how ATP is released to fulfil this function is not fully understood. Here we show that calcium homeostasis modulator 1 (CALHM1), a voltage-gated ion channel
2
,
3
, is indispensable for taste-stimuli-evoked ATP release from sweet-, bitter- and umami-sensing taste bud cells.
Calhm1
knockout mice have severely impaired perceptions of sweet, bitter and umami compounds, whereas their recognition of sour and salty tastes remains mostly normal.
Calhm1
deficiency affects taste perception without interfering with taste cell development or integrity. CALHM1 is expressed specifically in sweet/bitter/umami-sensing type II taste bud cells. Its heterologous expression induces a novel ATP permeability that releases ATP from cells in response to manipulations that activate the CALHM1 ion channel. Knockout of
Calhm1
strongly reduces voltage-gated currents in type II cells and taste-evoked ATP release from taste buds without affecting the excitability of taste cells by taste stimuli. Thus, CALHM1 is a voltage-gated ATP-release channel required for sweet, bitter and umami taste perception.
Journal Article
Rapid expansion and specialization of the TAS2R bitter taste receptor family in amphibians
TAS2Rs are a family of G protein-coupled receptors that function as bitter taste receptors in vertebrates. Mammalian TAS2Rs have historically garnered the most attention, leading to our understanding of their roles in taste perception relevant to human physiology and behaviors. However, the evolution and functional implications of TAS2Rs in other vertebrate lineages remain less explored. Here, we identify 9,291 TAS2Rs from 661 vertebrate genomes. Large-scale phylogenomic analyses reveal that frogs and salamanders contain unusually high TAS2R gene content, in stark contrast to other vertebrate lineages. In most species, TAS2R genes are found in clusters; compared to other vertebrates, amphibians have additional clusters and more genes per cluster. We find that vertebrate TAS2Rs have few one-to-one orthologs between closely related species, although total TAS2R count is stable in most lineages. Interestingly, TAS2R count is proportional to the receptors expressed solely in extra-oral tissues. In vitro receptor activity assays uncover that many amphibian TAS2Rs function as tissue-specific chemosensors to detect ecologically important xenobiotics.
Journal Article