Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Otolaryngol Head Neck Surg. 2016 Mar 29;

Authors: Saglam O, Altundag A, Cayonu M, Salihoglu M, Azizli E, Dursun E, Cetin B

Abstract
OBJECTIVE: In this study, we investigated the chemical senses (namely, olfaction), the 4 basic tastes, and umami taste in patients who underwent anterior palatoplasty (AP) for primary snoring.
STUDY DESIGN: Prospective clinical study.
SETTING: Multicenter, tertiary care hospitals.
SUBJECTS AND METHODS: The age range of the 28 participants was 22 to 47 years, and all had been diagnosed with primary snoring by polysomnography. Orthonasal and retronasal olfactory testing was performed using the respective "Sniffin' Sticks." Tests for the 4 basic tastes (sweet, sour, salty, and bitter) and umami were performed before and 6 months after AP.
RESULTS: The changes between the preoperative and postoperative results for the 4 basic tastes, which were applied to the anterior tongue region, were not significant. Retronasal olfactory function improved significantly 6 months after AP (P = .007). After AP, umami scores for the soft palate but not those of the anterior and posterior tongue decreased significantly (P = .001).
CONCLUSION: Patients scheduled for AP should be properly informed about potential postoperative taste and flavor changes. They should also be warned of a possible loss of appetite due to a postoperative decrease in the umami taste sensation of the soft palate.

PMID: 27026734 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RMQ18I

Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Otolaryngol Head Neck Surg. 2016 Mar 29;

Authors: Saglam O, Altundag A, Cayonu M, Salihoglu M, Azizli E, Dursun E, Cetin B

Abstract
OBJECTIVE: In this study, we investigated the chemical senses (namely, olfaction), the 4 basic tastes, and umami taste in patients who underwent anterior palatoplasty (AP) for primary snoring.
STUDY DESIGN: Prospective clinical study.
SETTING: Multicenter, tertiary care hospitals.
SUBJECTS AND METHODS: The age range of the 28 participants was 22 to 47 years, and all had been diagnosed with primary snoring by polysomnography. Orthonasal and retronasal olfactory testing was performed using the respective "Sniffin' Sticks." Tests for the 4 basic tastes (sweet, sour, salty, and bitter) and umami were performed before and 6 months after AP.
RESULTS: The changes between the preoperative and postoperative results for the 4 basic tastes, which were applied to the anterior tongue region, were not significant. Retronasal olfactory function improved significantly 6 months after AP (P = .007). After AP, umami scores for the soft palate but not those of the anterior and posterior tongue decreased significantly (P = .001).
CONCLUSION: Patients scheduled for AP should be properly informed about potential postoperative taste and flavor changes. They should also be warned of a possible loss of appetite due to a postoperative decrease in the umami taste sensation of the soft palate.

PMID: 27026734 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RMQ18I

Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Olfactory and Gustatory Functions after Anterior Palatoplasty in Patients with Primary Snoring.

Otolaryngol Head Neck Surg. 2016 Mar 29;

Authors: Saglam O, Altundag A, Cayonu M, Salihoglu M, Azizli E, Dursun E, Cetin B

Abstract
OBJECTIVE: In this study, we investigated the chemical senses (namely, olfaction), the 4 basic tastes, and umami taste in patients who underwent anterior palatoplasty (AP) for primary snoring.
STUDY DESIGN: Prospective clinical study.
SETTING: Multicenter, tertiary care hospitals.
SUBJECTS AND METHODS: The age range of the 28 participants was 22 to 47 years, and all had been diagnosed with primary snoring by polysomnography. Orthonasal and retronasal olfactory testing was performed using the respective "Sniffin' Sticks." Tests for the 4 basic tastes (sweet, sour, salty, and bitter) and umami were performed before and 6 months after AP.
RESULTS: The changes between the preoperative and postoperative results for the 4 basic tastes, which were applied to the anterior tongue region, were not significant. Retronasal olfactory function improved significantly 6 months after AP (P = .007). After AP, umami scores for the soft palate but not those of the anterior and posterior tongue decreased significantly (P = .001).
CONCLUSION: Patients scheduled for AP should be properly informed about potential postoperative taste and flavor changes. They should also be warned of a possible loss of appetite due to a postoperative decrease in the umami taste sensation of the soft palate.

PMID: 27026734 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RMQ18I

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Related Articles

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Nat Commun. 2015;6:6592

Authors: Yang B, Feng L, Wang F, Wang L

Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans.

PMID: 25791315 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1ocT8iD

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Related Articles

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Nat Commun. 2015;6:6592

Authors: Yang B, Feng L, Wang F, Wang L

Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans.

PMID: 25791315 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1ocT8iD

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Related Articles

Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

Nat Commun. 2015;6:6592

Authors: Yang B, Feng L, Wang F, Wang L

Abstract
Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans.

PMID: 25791315 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1ocT8iD

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

BMC Genomics. 2016;17(1):254

Authors: van Schooten B, Jiggins CD, Briscoe AD, Papa R

Abstract
BACKGROUND: In a world of chemical cues, smell and taste are essential senses for survival. Here we focused on Heliconius, a diverse group of butterflies that exhibit variation in pre- and post-zygotic isolation and chemically-mediated behaviors across their phylogeny. Our study examined the ionotropic receptors, a recently discovered class of receptors that are some of the most ancient chemical receptors.
RESULTS: We found more ionotropic receptors in Heliconius (31) than in Bombyx mori (25) or in Danaus plexippus (27). Sixteen genes in Lepidoptera were not present in Diptera. Only IR7d4 was exclusively found in butterflies and two expansions of IR60a were exclusive to Heliconius. A genome-wide comparison between 11 Heliconius species revealed instances of pseudogenization, gene gain, and signatures of positive selection across the phylogeny. IR60a2b and IR60a2d are unique to the H. melpomene, H. cydno, and H. timareta clade, a group where chemosensing is likely involved in pre-zygotic isolation. IR60a2b also displayed copy number variations (CNVs) in distinct populations of H. melpomene and was the only gene significantly higher expressed in legs and mouthparts than in antennae, which suggests a gustatory function. dN/dS analysis suggests more frequent positive selection in some intronless IR genes and in particular in the sara/sapho and melpomene/cydno/timareta clades. IR60a1 was the only gene with an elevated dN/dS along a major phylogenetic branch associated with pupal mating. Only IR93a was differentially expressed between sexes.
CONCLUSIONS: All together these data make Heliconius butterflies one of the very few insects outside Drosophila where IRs have been characterized in detail. Our work outlines a dynamic pattern of IR gene evolution throughout the Heliconius radiation which could be the result of selective pressure to find potential mates or host-plants.

PMID: 27004525 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNlDW

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Chem Senses. 2016 Mar 20;

Authors: Seow YX, Ong PK, Huang D

Abstract
The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21-80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age.

PMID: 27001718 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22HyXJi

Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

Related Articles

Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

PLoS One. 2015;10(6):e0130997

Authors: Murovets VO, Bachmanov AA, Zolotarev VA

Abstract
The G-protein-coupled sweet taste receptor dimer T1R2/T1R3 is expressed in taste bud cells in the oral cavity. In recent years, its involvement in membrane glucose sensing was discovered in endocrine cells regulating glucose homeostasis. We investigated importance of extraorally expressed T1R3 taste receptor protein in age-dependent control of blood glucose homeostasis in vivo, using nonfasted mice with a targeted mutation of the Tas1r3 gene that encodes the T1R3 protein. Glucose and insulin tolerance tests, as well as behavioral tests measuring taste responses to sucrose solutions, were performed with C57BL/6ByJ (Tas1r3+/+) inbred mice bearing the wild-type allele and C57BL/6J-Tas1r3tm1Rfm mice lacking the entire Tas1r3 coding region and devoid of the T1R3 protein (Tas1r3-/-). Compared with Tas1r3+/+ mice, Tas1r3-/- mice lacked attraction to sucrose in brief-access licking tests, had diminished taste preferences for sucrose solutions in the two-bottle tests, and had reduced insulin sensitivity and tolerance to glucose administered intraperitoneally or intragastrically, which suggests that these effects are due to absence of T1R3. Impairment of glucose clearance in Tas1r3-/- mice was exacerbated with age after intraperitoneal but not intragastric administration of glucose, pointing to a compensatory role of extraoral T1R3-dependent mechanisms in offsetting age-dependent decline in regulation of glucose homeostasis. Incretin effects were similar in Tas1r3+/+ and Tas1r3-/- mice, which suggests that control of blood glucose clearance is associated with effects of extraoral T1R3 in tissues other than the gastrointestinal tract. Collectively, the obtained data demonstrate that the T1R3 receptor protein plays an important role in control of glucose homeostasis not only by regulating sugar intake but also via its extraoral function, probably in the pancreas and brain.

PMID: 26107521 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNoQb

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

Related Articles

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

J Fluoresc. 2015 May;25(3):557-61

Authors: Liu W, Wu G, Gu X, Yuan X, Li J, Wang H

Abstract
A new probe based on oxadiazole derivative (OXD) containing Schiff base moiety was synthesised as fluorescence turn-on sensor S1 . Furthermore, its fluorescents spectra (FS) result demonstrate that S1 selectively senses bivalent lead ion (Pb(2+)) in HEPES buffer solution (10 mM, pH = 7.0,DMF-H2O, 9:1, v/v), so S1 was a viable candidate as fluorescent receptor for a new Pb(2+) sensor. And the results of fluorescent spectral titration showed this sensor formed 1:1complex with Pb(2+).

PMID: 25791758 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNoQ3

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

BMC Genomics. 2016;17(1):254

Authors: van Schooten B, Jiggins CD, Briscoe AD, Papa R

Abstract
BACKGROUND: In a world of chemical cues, smell and taste are essential senses for survival. Here we focused on Heliconius, a diverse group of butterflies that exhibit variation in pre- and post-zygotic isolation and chemically-mediated behaviors across their phylogeny. Our study examined the ionotropic receptors, a recently discovered class of receptors that are some of the most ancient chemical receptors.
RESULTS: We found more ionotropic receptors in Heliconius (31) than in Bombyx mori (25) or in Danaus plexippus (27). Sixteen genes in Lepidoptera were not present in Diptera. Only IR7d4 was exclusively found in butterflies and two expansions of IR60a were exclusive to Heliconius. A genome-wide comparison between 11 Heliconius species revealed instances of pseudogenization, gene gain, and signatures of positive selection across the phylogeny. IR60a2b and IR60a2d are unique to the H. melpomene, H. cydno, and H. timareta clade, a group where chemosensing is likely involved in pre-zygotic isolation. IR60a2b also displayed copy number variations (CNVs) in distinct populations of H. melpomene and was the only gene significantly higher expressed in legs and mouthparts than in antennae, which suggests a gustatory function. dN/dS analysis suggests more frequent positive selection in some intronless IR genes and in particular in the sara/sapho and melpomene/cydno/timareta clades. IR60a1 was the only gene with an elevated dN/dS along a major phylogenetic branch associated with pupal mating. Only IR93a was differentially expressed between sexes.
CONCLUSIONS: All together these data make Heliconius butterflies one of the very few insects outside Drosophila where IRs have been characterized in detail. Our work outlines a dynamic pattern of IR gene evolution throughout the Heliconius radiation which could be the result of selective pressure to find potential mates or host-plants.

PMID: 27004525 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNlDW

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Chem Senses. 2016 Mar 20;

Authors: Seow YX, Ong PK, Huang D

Abstract
The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21-80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age.

PMID: 27001718 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22HyXJi

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

Related Articles

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

J Fluoresc. 2015 May;25(3):557-61

Authors: Liu W, Wu G, Gu X, Yuan X, Li J, Wang H

Abstract
A new probe based on oxadiazole derivative (OXD) containing Schiff base moiety was synthesised as fluorescence turn-on sensor S1 . Furthermore, its fluorescents spectra (FS) result demonstrate that S1 selectively senses bivalent lead ion (Pb(2+)) in HEPES buffer solution (10 mM, pH = 7.0,DMF-H2O, 9:1, v/v), so S1 was a viable candidate as fluorescent receptor for a new Pb(2+) sensor. And the results of fluorescent spectral titration showed this sensor formed 1:1complex with Pb(2+).

PMID: 25791758 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNoQ3

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

Genome-wide analysis of ionotropic receptors provides insight into their evolution in Heliconius butterflies.

BMC Genomics. 2016;17(1):254

Authors: van Schooten B, Jiggins CD, Briscoe AD, Papa R

Abstract
BACKGROUND: In a world of chemical cues, smell and taste are essential senses for survival. Here we focused on Heliconius, a diverse group of butterflies that exhibit variation in pre- and post-zygotic isolation and chemically-mediated behaviors across their phylogeny. Our study examined the ionotropic receptors, a recently discovered class of receptors that are some of the most ancient chemical receptors.
RESULTS: We found more ionotropic receptors in Heliconius (31) than in Bombyx mori (25) or in Danaus plexippus (27). Sixteen genes in Lepidoptera were not present in Diptera. Only IR7d4 was exclusively found in butterflies and two expansions of IR60a were exclusive to Heliconius. A genome-wide comparison between 11 Heliconius species revealed instances of pseudogenization, gene gain, and signatures of positive selection across the phylogeny. IR60a2b and IR60a2d are unique to the H. melpomene, H. cydno, and H. timareta clade, a group where chemosensing is likely involved in pre-zygotic isolation. IR60a2b also displayed copy number variations (CNVs) in distinct populations of H. melpomene and was the only gene significantly higher expressed in legs and mouthparts than in antennae, which suggests a gustatory function. dN/dS analysis suggests more frequent positive selection in some intronless IR genes and in particular in the sara/sapho and melpomene/cydno/timareta clades. IR60a1 was the only gene with an elevated dN/dS along a major phylogenetic branch associated with pupal mating. Only IR93a was differentially expressed between sexes.
CONCLUSIONS: All together these data make Heliconius butterflies one of the very few insects outside Drosophila where IRs have been characterized in detail. Our work outlines a dynamic pattern of IR gene evolution throughout the Heliconius radiation which could be the result of selective pressure to find potential mates or host-plants.

PMID: 27004525 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNlDW

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test.

Chem Senses. 2016 Mar 20;

Authors: Seow YX, Ong PK, Huang D

Abstract
The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21-80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age.

PMID: 27001718 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22HyXJi

Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

Related Articles

Impaired Glucose Metabolism in Mice Lacking the Tas1r3 Taste Receptor Gene.

PLoS One. 2015;10(6):e0130997

Authors: Murovets VO, Bachmanov AA, Zolotarev VA

Abstract
The G-protein-coupled sweet taste receptor dimer T1R2/T1R3 is expressed in taste bud cells in the oral cavity. In recent years, its involvement in membrane glucose sensing was discovered in endocrine cells regulating glucose homeostasis. We investigated importance of extraorally expressed T1R3 taste receptor protein in age-dependent control of blood glucose homeostasis in vivo, using nonfasted mice with a targeted mutation of the Tas1r3 gene that encodes the T1R3 protein. Glucose and insulin tolerance tests, as well as behavioral tests measuring taste responses to sucrose solutions, were performed with C57BL/6ByJ (Tas1r3+/+) inbred mice bearing the wild-type allele and C57BL/6J-Tas1r3tm1Rfm mice lacking the entire Tas1r3 coding region and devoid of the T1R3 protein (Tas1r3-/-). Compared with Tas1r3+/+ mice, Tas1r3-/- mice lacked attraction to sucrose in brief-access licking tests, had diminished taste preferences for sucrose solutions in the two-bottle tests, and had reduced insulin sensitivity and tolerance to glucose administered intraperitoneally or intragastrically, which suggests that these effects are due to absence of T1R3. Impairment of glucose clearance in Tas1r3-/- mice was exacerbated with age after intraperitoneal but not intragastric administration of glucose, pointing to a compensatory role of extraoral T1R3-dependent mechanisms in offsetting age-dependent decline in regulation of glucose homeostasis. Incretin effects were similar in Tas1r3+/+ and Tas1r3-/- mice, which suggests that control of blood glucose clearance is associated with effects of extraoral T1R3 in tissues other than the gastrointestinal tract. Collectively, the obtained data demonstrate that the T1R3 receptor protein plays an important role in control of glucose homeostasis not only by regulating sugar intake but also via its extraoral function, probably in the pancreas and brain.

PMID: 26107521 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNoQb

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

Related Articles

Synthesis of Schiff base-Based 1,2,4-Oxadiazole Derivative as Fluorescence Turn-On Sensor for High Selectivity of Pb(2.).

J Fluoresc. 2015 May;25(3):557-61

Authors: Liu W, Wu G, Gu X, Yuan X, Li J, Wang H

Abstract
A new probe based on oxadiazole derivative (OXD) containing Schiff base moiety was synthesised as fluorescence turn-on sensor S1 . Furthermore, its fluorescents spectra (FS) result demonstrate that S1 selectively senses bivalent lead ion (Pb(2+)) in HEPES buffer solution (10 mM, pH = 7.0,DMF-H2O, 9:1, v/v), so S1 was a viable candidate as fluorescent receptor for a new Pb(2+) sensor. And the results of fluorescent spectral titration showed this sensor formed 1:1complex with Pb(2+).

PMID: 25791758 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RiNoQ3

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test

The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21–80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/21Epr7l

Exploring Ethnic Differences in Taste Perception.

Exploring Ethnic Differences in Taste Perception.

Chem Senses. 2016 Mar 18;

Authors: Williams JA, Bartoshuk LM, Fillingim RB, Dotson CD

Abstract
It is well known that nutritional intake can vary substantially as a function of demographic variables such as ethnicity and/or sex. Although a variety of factors are known to underlie the relationship between these demographic variables and nutritional intake, it is interesting to speculate that variation in food intake associated with ethnicity or sex may result, in part, from differences in the perceived taste of foods in these different populations. Thus, we initiated a study to evaluate taste responsiveness in different ethnic groups. Moreover, because of the known differences in taste responsiveness between males and females, analyses were stratified by sex. The ethnic groups tested differed significantly from one another in reported perceived taste intensity. Our results showed that Hispanics and African Americans rated taste sensations higher than non-Hispanic Whites and that these differences were more pronounced in males. Understanding the nature of these differences in taste perception is important, because taste perception may contribute to dietary health risk. When attempting to modify diet, individuals of different ethnicities may require personalized interventions that take into account the different sensory experience that these individuals may have when consuming foods.

PMID: 26994473 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1Vqa1nA

Exploring Ethnic Differences in Taste Perception.

Exploring Ethnic Differences in Taste Perception.

Chem Senses. 2016 Mar 18;

Authors: Williams JA, Bartoshuk LM, Fillingim RB, Dotson CD

Abstract
It is well known that nutritional intake can vary substantially as a function of demographic variables such as ethnicity and/or sex. Although a variety of factors are known to underlie the relationship between these demographic variables and nutritional intake, it is interesting to speculate that variation in food intake associated with ethnicity or sex may result, in part, from differences in the perceived taste of foods in these different populations. Thus, we initiated a study to evaluate taste responsiveness in different ethnic groups. Moreover, because of the known differences in taste responsiveness between males and females, analyses were stratified by sex. The ethnic groups tested differed significantly from one another in reported perceived taste intensity. Our results showed that Hispanics and African Americans rated taste sensations higher than non-Hispanic Whites and that these differences were more pronounced in males. Understanding the nature of these differences in taste perception is important, because taste perception may contribute to dietary health risk. When attempting to modify diet, individuals of different ethnicities may require personalized interventions that take into account the different sensory experience that these individuals may have when consuming foods.

PMID: 26994473 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1Vqa1nA

Exploring Ethnic Differences in Taste Perception.

Exploring Ethnic Differences in Taste Perception.

Chem Senses. 2016 Mar 18;

Authors: Williams JA, Bartoshuk LM, Fillingim RB, Dotson CD

Abstract
It is well known that nutritional intake can vary substantially as a function of demographic variables such as ethnicity and/or sex. Although a variety of factors are known to underlie the relationship between these demographic variables and nutritional intake, it is interesting to speculate that variation in food intake associated with ethnicity or sex may result, in part, from differences in the perceived taste of foods in these different populations. Thus, we initiated a study to evaluate taste responsiveness in different ethnic groups. Moreover, because of the known differences in taste responsiveness between males and females, analyses were stratified by sex. The ethnic groups tested differed significantly from one another in reported perceived taste intensity. Our results showed that Hispanics and African Americans rated taste sensations higher than non-Hispanic Whites and that these differences were more pronounced in males. Understanding the nature of these differences in taste perception is important, because taste perception may contribute to dietary health risk. When attempting to modify diet, individuals of different ethnicities may require personalized interventions that take into account the different sensory experience that these individuals may have when consuming foods.

PMID: 26994473 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1Vqa1nA

Exploring Ethnic Differences in Taste Perception

It is well known that nutritional intake can vary substantially as a function of demographic variables such as ethnicity and/or sex. Although a variety of factors are known to underlie the relationship between these demographic variables and nutritional intake, it is interesting to speculate that variation in food intake associated with ethnicity or sex may result, in part, from differences in the perceived taste of foods in these different populations. Thus, we initiated a study to evaluate taste responsiveness in different ethnic groups. Moreover, because of the known differences in taste responsiveness between males and females, analyses were stratified by sex. The ethnic groups tested differed significantly from one another in reported perceived taste intensity. Our results showed that Hispanics and African Americans rated taste sensations higher than non-Hispanic Whites and that these differences were more pronounced in males. Understanding the nature of these differences in taste perception is important, because taste perception may contribute to dietary health risk. When attempting to modify diet, individuals of different ethnicities may require personalized interventions that take into account the different sensory experience that these individuals may have when consuming foods.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1R6Fo4J

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Chem Senses. 2016 Mar 14;

Authors: Lemon CH, Kang Y, Li J

Abstract
Oral temperature is a component and modifier of taste perception. Both trigeminal (V) and taste-sensitive cells, including those in the nucleus of the solitary tract (NTS), can respond to oral temperature. However, functional associations in thermal sensitivity between V and gustatory neurons are poorly understood. To study this we recorded electrophysiological responses to oral stimulation with cool (9, 15, 25, 32, and 34 °C) and warm (40 and 45 °C) temperatures from medullary V (n = 45) and taste-sensitive NTS (n = 27) neurons in anesthetized mice. Results showed temperatures below 34 °C activated the majority of V neurons but only a minority of NTS units. V neurons displayed larger responses to cooling and responded to temperatures that poorly stimulated NTS cells. Multivariate analyses revealed different temperatures induced larger differences in responses across V compared with NTS neurons, indicating V pathways possess greater capacity to signal temperature. Conversely, responses to temperature in NTS units associated with gustatory tuning. Further analyses identified two types of cooling-sensitive V neurons oriented toward innocuous or noxious cooling. Multivariate analyses indicated the combined response of these cells afforded distinction among a broad range of cool temperatures, suggesting multiple types of V neurons work together to represent oral cooling.

PMID: 26976122 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1UfnPS5

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Chem Senses. 2016 Mar 14;

Authors: Sailer U, Triscoli C, Croy I

Abstract
Typically, the subjective pleasantness of an odor decreases after it has been repeatedly smelled. This study investigates how the pleasantness ("liking") and the wish to be further exposed to the same odor ("wanting") are affected by variety on a longer time scale, and how they relate to actual food intake. Twenty-five participants rated a coconut odor presented 120 times for its liking and wanting before being offered coconut sweets. The amount eaten was assessed. Individual patterns of change were described by fitting 3 different models to the ratings. To study effects of variety on odor evaluation, the ratings were compared with a previous study where coconut was 1 of 3 odors presented in an alternating way. Initially, both liking and wanting the odors were high, but decreased over repetitions in 75% of the subjects. About 40% of all subjects showed an exponential change of ratings, 40% a step-like change, and 20% a linear change. Food intake was not related to the pattern of change in the ratings. Moreover, decreased olfactory pleasure did not seem to affect eating behavior. However, participants who rated the coconut odor higher at the beginning ate twice as many sweets as the others. Odor variety did not affect the experienced pleasure of smelling (liking), but did affect the motivation to experience the same smell again (wanting). This has not been reported for food or touch stimulation and may be specific for the perception of odors.

PMID: 26976121 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RlYRdp

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Chem Senses. 2016 Mar 14;

Authors: Lemon CH, Kang Y, Li J

Abstract
Oral temperature is a component and modifier of taste perception. Both trigeminal (V) and taste-sensitive cells, including those in the nucleus of the solitary tract (NTS), can respond to oral temperature. However, functional associations in thermal sensitivity between V and gustatory neurons are poorly understood. To study this we recorded electrophysiological responses to oral stimulation with cool (9, 15, 25, 32, and 34 °C) and warm (40 and 45 °C) temperatures from medullary V (n = 45) and taste-sensitive NTS (n = 27) neurons in anesthetized mice. Results showed temperatures below 34 °C activated the majority of V neurons but only a minority of NTS units. V neurons displayed larger responses to cooling and responded to temperatures that poorly stimulated NTS cells. Multivariate analyses revealed different temperatures induced larger differences in responses across V compared with NTS neurons, indicating V pathways possess greater capacity to signal temperature. Conversely, responses to temperature in NTS units associated with gustatory tuning. Further analyses identified two types of cooling-sensitive V neurons oriented toward innocuous or noxious cooling. Multivariate analyses indicated the combined response of these cells afforded distinction among a broad range of cool temperatures, suggesting multiple types of V neurons work together to represent oral cooling.

PMID: 26976122 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1UfnPS5

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Chem Senses. 2016 Mar 14;

Authors: Sailer U, Triscoli C, Croy I

Abstract
Typically, the subjective pleasantness of an odor decreases after it has been repeatedly smelled. This study investigates how the pleasantness ("liking") and the wish to be further exposed to the same odor ("wanting") are affected by variety on a longer time scale, and how they relate to actual food intake. Twenty-five participants rated a coconut odor presented 120 times for its liking and wanting before being offered coconut sweets. The amount eaten was assessed. Individual patterns of change were described by fitting 3 different models to the ratings. To study effects of variety on odor evaluation, the ratings were compared with a previous study where coconut was 1 of 3 odors presented in an alternating way. Initially, both liking and wanting the odors were high, but decreased over repetitions in 75% of the subjects. About 40% of all subjects showed an exponential change of ratings, 40% a step-like change, and 20% a linear change. Food intake was not related to the pattern of change in the ratings. Moreover, decreased olfactory pleasure did not seem to affect eating behavior. However, participants who rated the coconut odor higher at the beginning ate twice as many sweets as the others. Odor variety did not affect the experienced pleasure of smelling (liking), but did affect the motivation to experience the same smell again (wanting). This has not been reported for food or touch stimulation and may be specific for the perception of odors.

PMID: 26976121 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RlYRdp

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons.

Chem Senses. 2016 Mar 14;

Authors: Lemon CH, Kang Y, Li J

Abstract
Oral temperature is a component and modifier of taste perception. Both trigeminal (V) and taste-sensitive cells, including those in the nucleus of the solitary tract (NTS), can respond to oral temperature. However, functional associations in thermal sensitivity between V and gustatory neurons are poorly understood. To study this we recorded electrophysiological responses to oral stimulation with cool (9, 15, 25, 32, and 34 °C) and warm (40 and 45 °C) temperatures from medullary V (n = 45) and taste-sensitive NTS (n = 27) neurons in anesthetized mice. Results showed temperatures below 34 °C activated the majority of V neurons but only a minority of NTS units. V neurons displayed larger responses to cooling and responded to temperatures that poorly stimulated NTS cells. Multivariate analyses revealed different temperatures induced larger differences in responses across V compared with NTS neurons, indicating V pathways possess greater capacity to signal temperature. Conversely, responses to temperature in NTS units associated with gustatory tuning. Further analyses identified two types of cooling-sensitive V neurons oriented toward innocuous or noxious cooling. Multivariate analyses indicated the combined response of these cells afforded distinction among a broad range of cool temperatures, suggesting multiple types of V neurons work together to represent oral cooling.

PMID: 26976122 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1UfnPS5

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Still Eating Despite Decreased Olfactory Pleasure-The Influence of Odor Liking and Wanting on Food Intake.

Chem Senses. 2016 Mar 14;

Authors: Sailer U, Triscoli C, Croy I

Abstract
Typically, the subjective pleasantness of an odor decreases after it has been repeatedly smelled. This study investigates how the pleasantness ("liking") and the wish to be further exposed to the same odor ("wanting") are affected by variety on a longer time scale, and how they relate to actual food intake. Twenty-five participants rated a coconut odor presented 120 times for its liking and wanting before being offered coconut sweets. The amount eaten was assessed. Individual patterns of change were described by fitting 3 different models to the ratings. To study effects of variety on odor evaluation, the ratings were compared with a previous study where coconut was 1 of 3 odors presented in an alternating way. Initially, both liking and wanting the odors were high, but decreased over repetitions in 75% of the subjects. About 40% of all subjects showed an exponential change of ratings, 40% a step-like change, and 20% a linear change. Food intake was not related to the pattern of change in the ratings. Moreover, decreased olfactory pleasure did not seem to affect eating behavior. However, participants who rated the coconut odor higher at the beginning ate twice as many sweets as the others. Odor variety did not affect the experienced pleasure of smelling (liking), but did affect the motivation to experience the same smell again (wanting). This has not been reported for food or touch stimulation and may be specific for the perception of odors.

PMID: 26976121 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1RlYRdp

Separate functions for responses to oral temperature in thermo-gustatory and trigeminal neurons

Oral temperature is a component and modifier of taste perception. Both trigeminal (V) and taste-sensitive cells, including those in the nucleus of the solitary tract (NTS), can respond to oral temperature. However, functional associations in thermal sensitivity between V and gustatory neurons are poorly understood. To study this we recorded electrophysiological responses to oral stimulation with cool (9, 15, 25, 32, and 34 °C) and warm (40 and 45 °C) temperatures from medullary V (n = 45) and taste-sensitive NTS (n = 27) neurons in anesthetized mice. Results showed temperatures below 34 °C activated the majority of V neurons but only a minority of NTS units. V neurons displayed larger responses to cooling and responded to temperatures that poorly stimulated NTS cells. Multivariate analyses revealed different temperatures induced larger differences in responses across V compared with NTS neurons, indicating V pathways possess greater capacity to signal temperature. Conversely, responses to temperature in NTS units associated with gustatory tuning. Further analyses identified two types of cooling-sensitive V neurons oriented toward innocuous or noxious cooling. Multivariate analyses indicated the combined response of these cells afforded distinction among a broad range of cool temperatures, suggesting multiple types of V neurons work together to represent oral cooling.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1S1fEW4

Still Eating Despite Decreased Olfactory Pleasure--The Influence of Odor Liking and Wanting on Food Intake

Typically, the subjective pleasantness of an odor decreases after it has been repeatedly smelled. This study investigates how the pleasantness ("liking") and the wish to be further exposed to the same odor ("wanting") are affected by variety on a longer time scale, and how they relate to actual food intake. Twenty-five participants rated a coconut odor presented 120 times for its liking and wanting before being offered coconut sweets. The amount eaten was assessed. Individual patterns of change were described by fitting 3 different models to the ratings. To study effects of variety on odor evaluation, the ratings were compared with a previous study where coconut was 1 of 3 odors presented in an alternating way. Initially, both liking and wanting the odors were high, but decreased over repetitions in 75% of the subjects. About 40% of all subjects showed an exponential change of ratings, 40% a step-like change, and 20% a linear change. Food intake was not related to the pattern of change in the ratings. Moreover, decreased olfactory pleasure did not seem to affect eating behavior. However, participants who rated the coconut odor higher at the beginning ate twice as many sweets as the others. Odor variety did not affect the experienced pleasure of smelling (liking), but did affect the motivation to experience the same smell again (wanting). This has not been reported for food or touch stimulation and may be specific for the perception of odors.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pIg3na

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Chem Senses. 2016 Mar 11;

Authors: Ye Z, Liu F, Liu N

Abstract
Mosquito control is essential to protect humans from mosquito-borne diseases. The host recognition between mosquitoes and humans is achieved by the mosquito olfactory system. Antennal sensilla, which house olfactory receptor neurons, are responsible for detecting chemical cues from hosts. To deepen our understanding of the mechanisms involved in the host seeking behavior of mosquitoes, we conducted an electrophysiological study to investigate the response profile of each type of antennal sensilla to human odorants using single sensillum recording. In this study, more than 100 human odorants have been applied as stimuli to 5 morphological types of sensilla, long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBTI), short blunt trichoid II (SBTII), and grooved peg (GP). Different types of sensilla present distinctive response profiles to the human odorants tested. In particular, SST, SBTI, and SBTII sensilla responded to more than 1 category of human odorants, while GP and LST were narrowly tuned to amines and methyl nonanoate, respectively. The dose-dependent patterns and odorant-specific/chemical structure-specific temporal dynamics of SBTI and SBTII antennal sensilla to human odorants had been further detected. Taken together, our study provides the new information on the olfactory physiology of Culex quinquefasciatus (Diptera: Culicidae) to human odorants, leading to a better understanding of mosquito-host recognition and being important for future development of new reagents in the mosquito control.

PMID: 26969630 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XmWnjv

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Chem Senses. 2016 Mar 11;

Authors: Roddick KM, Roberts AD, Schellinck HM, Brown RE

Abstract
Deficits in odor identification and detection are early symptoms of Alzheimer's disease (AD). Two transgenic mouse models of AD, the 5XFAD and the 3×Tg-AD mice and their wildtype controls, were assessed for olfactory detection with decreasing concentrations of ethyl acetate in a go no-go operant olfactometer task at 6 months of age. For both the 5XFAD and their B6SJLF1 wildtype littermates, females made fewer errors in detecting the ethyl acetate than males on all but the lowest odor concentrations. Female 5XFAD mice performed slightly better than their female wildtype littermates on the higher odor concentrations, though not at the lowest concentration. The 3×Tg-AD females showed decreased olfactory detection compared with their wildtype B6129S1 controls, whereas there was no difference in the males. Therefore, although the 5XFAD mice showed no olfactory detection deficits, female 3×Tg-AD mice had impaired olfactory detection at low odor concentrations but males did not. This difference in odor detection should be considered in studies of olfactory learning and memory, as differences in performance may be due to sensory rather than cognitive factors, though detection seems unimpaired at high odor concentrations.

PMID: 26969629 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22aKILo

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Chem Senses. 2016 Mar 11;

Authors: Ye Z, Liu F, Liu N

Abstract
Mosquito control is essential to protect humans from mosquito-borne diseases. The host recognition between mosquitoes and humans is achieved by the mosquito olfactory system. Antennal sensilla, which house olfactory receptor neurons, are responsible for detecting chemical cues from hosts. To deepen our understanding of the mechanisms involved in the host seeking behavior of mosquitoes, we conducted an electrophysiological study to investigate the response profile of each type of antennal sensilla to human odorants using single sensillum recording. In this study, more than 100 human odorants have been applied as stimuli to 5 morphological types of sensilla, long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBTI), short blunt trichoid II (SBTII), and grooved peg (GP). Different types of sensilla present distinctive response profiles to the human odorants tested. In particular, SST, SBTI, and SBTII sensilla responded to more than 1 category of human odorants, while GP and LST were narrowly tuned to amines and methyl nonanoate, respectively. The dose-dependent patterns and odorant-specific/chemical structure-specific temporal dynamics of SBTI and SBTII antennal sensilla to human odorants had been further detected. Taken together, our study provides the new information on the olfactory physiology of Culex quinquefasciatus (Diptera: Culicidae) to human odorants, leading to a better understanding of mosquito-host recognition and being important for future development of new reagents in the mosquito control.

PMID: 26969630 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XmWnjv

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Chem Senses. 2016 Mar 11;

Authors: Roddick KM, Roberts AD, Schellinck HM, Brown RE

Abstract
Deficits in odor identification and detection are early symptoms of Alzheimer's disease (AD). Two transgenic mouse models of AD, the 5XFAD and the 3×Tg-AD mice and their wildtype controls, were assessed for olfactory detection with decreasing concentrations of ethyl acetate in a go no-go operant olfactometer task at 6 months of age. For both the 5XFAD and their B6SJLF1 wildtype littermates, females made fewer errors in detecting the ethyl acetate than males on all but the lowest odor concentrations. Female 5XFAD mice performed slightly better than their female wildtype littermates on the higher odor concentrations, though not at the lowest concentration. The 3×Tg-AD females showed decreased olfactory detection compared with their wildtype B6129S1 controls, whereas there was no difference in the males. Therefore, although the 5XFAD mice showed no olfactory detection deficits, female 3×Tg-AD mice had impaired olfactory detection at low odor concentrations but males did not. This difference in odor detection should be considered in studies of olfactory learning and memory, as differences in performance may be due to sensory rather than cognitive factors, though detection seems unimpaired at high odor concentrations.

PMID: 26969629 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22aKILo

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants.

Chem Senses. 2016 Mar 11;

Authors: Ye Z, Liu F, Liu N

Abstract
Mosquito control is essential to protect humans from mosquito-borne diseases. The host recognition between mosquitoes and humans is achieved by the mosquito olfactory system. Antennal sensilla, which house olfactory receptor neurons, are responsible for detecting chemical cues from hosts. To deepen our understanding of the mechanisms involved in the host seeking behavior of mosquitoes, we conducted an electrophysiological study to investigate the response profile of each type of antennal sensilla to human odorants using single sensillum recording. In this study, more than 100 human odorants have been applied as stimuli to 5 morphological types of sensilla, long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBTI), short blunt trichoid II (SBTII), and grooved peg (GP). Different types of sensilla present distinctive response profiles to the human odorants tested. In particular, SST, SBTI, and SBTII sensilla responded to more than 1 category of human odorants, while GP and LST were narrowly tuned to amines and methyl nonanoate, respectively. The dose-dependent patterns and odorant-specific/chemical structure-specific temporal dynamics of SBTI and SBTII antennal sensilla to human odorants had been further detected. Taken together, our study provides the new information on the olfactory physiology of Culex quinquefasciatus (Diptera: Culicidae) to human odorants, leading to a better understanding of mosquito-host recognition and being important for future development of new reagents in the mosquito control.

PMID: 26969630 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XmWnjv

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Sex and Genotype Differences in Odor Detection in the 3×Tg-AD and 5XFAD Mouse Models of Alzheimer's Disease at 6 Months of Age.

Chem Senses. 2016 Mar 11;

Authors: Roddick KM, Roberts AD, Schellinck HM, Brown RE

Abstract
Deficits in odor identification and detection are early symptoms of Alzheimer's disease (AD). Two transgenic mouse models of AD, the 5XFAD and the 3×Tg-AD mice and their wildtype controls, were assessed for olfactory detection with decreasing concentrations of ethyl acetate in a go no-go operant olfactometer task at 6 months of age. For both the 5XFAD and their B6SJLF1 wildtype littermates, females made fewer errors in detecting the ethyl acetate than males on all but the lowest odor concentrations. Female 5XFAD mice performed slightly better than their female wildtype littermates on the higher odor concentrations, though not at the lowest concentration. The 3×Tg-AD females showed decreased olfactory detection compared with their wildtype B6129S1 controls, whereas there was no difference in the males. Therefore, although the 5XFAD mice showed no olfactory detection deficits, female 3×Tg-AD mice had impaired olfactory detection at low odor concentrations but males did not. This difference in odor detection should be considered in studies of olfactory learning and memory, as differences in performance may be due to sensory rather than cognitive factors, though detection seems unimpaired at high odor concentrations.

PMID: 26969629 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/22aKILo

Olfactory Responses of Southern House Mosquito, Culex quinquefasciatus, to Human Odorants

Mosquito control is essential to protect humans from mosquito-borne diseases. The host recognition between mosquitoes and humans is achieved by the mosquito olfactory system. Antennal sensilla, which house olfactory receptor neurons, are responsible for detecting chemical cues from hosts. To deepen our understanding of the mechanisms involved in the host seeking behavior of mosquitoes, we conducted an electrophysiological study to investigate the response profile of each type of antennal sensilla to human odorants using single sensillum recording. In this study, more than 100 human odorants have been applied as stimuli to 5 morphological types of sensilla, long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBTI), short blunt trichoid II (SBTII), and grooved peg (GP). Different types of sensilla present distinctive response profiles to the human odorants tested. In particular, SST, SBTI, and SBTII sensilla responded to more than 1 category of human odorants, while GP and LST were narrowly tuned to amines and methyl nonanoate, respectively. The dose-dependent patterns and odorant-specific/chemical structure-specific temporal dynamics of SBTI and SBTII antennal sensilla to human odorants had been further detected. Taken together, our study provides the new information on the olfactory physiology of Culex quinquefasciatus (Diptera: Culicidae) to human odorants, leading to a better understanding of mosquito-host recognition and being important for future development of new reagents in the mosquito control.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1QNUTOK

Sex and Genotype Differences in Odor Detection in the 3xTg-AD and 5XFAD Mouse Models of Alzheimers Disease at 6 Months of Age

Deficits in odor identification and detection are early symptoms of Alzheimer’s disease (AD). Two transgenic mouse models of AD, the 5XFAD and the 3xTg-AD mice and their wildtype controls, were assessed for olfactory detection with decreasing concentrations of ethyl acetate in a go no-go operant olfactometer task at 6 months of age. For both the 5XFAD and their B6SJLF1 wildtype littermates, females made fewer errors in detecting the ethyl acetate than males on all but the lowest odor concentrations. Female 5XFAD mice performed slightly better than their female wildtype littermates on the higher odor concentrations, though not at the lowest concentration. The 3xTg-AD females showed decreased olfactory detection compared with their wildtype B6129S1 controls, whereas there was no difference in the males. Therefore, although the 5XFAD mice showed no olfactory detection deficits, female 3xTg-AD mice had impaired olfactory detection at low odor concentrations but males did not. This difference in odor detection should be considered in studies of olfactory learning and memory, as differences in performance may be due to sensory rather than cognitive factors, though detection seems unimpaired at high odor concentrations.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pe8V1q

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

J Neurosci. 2016 Mar 9;36(10):2995-3006

Authors: Dibattista M, Reisert J

Abstract
UNLABELLED: Olfactory receptor neurons (ORNs) in the nasal cavity detect and transduce odorants into action potentials to be conveyed to the olfactory bulb. Odorants are delivered to ORNs via the inhaled air at breathing frequencies that can vary from 2 to 10 Hz in the mouse. Thus olfactory transduction should occur at sufficient speed such that it can accommodate repetitive and frequent stimulation. Activation of odorant receptors (ORs) leads to adenylyl cyclase III activation, cAMP increase, and opening of cyclic nucleotide-gated channels. This makes the kinetic regulation of cAMP one of the important determinants for the response time course. We addressed the dynamic regulation of cAMP during the odorant response and examined how basal levels of cAMP are controlled. The latter is particularly relevant as basal cAMP depends on the basal activity of the expressed OR and thus varies across ORNs. We found that olfactory marker protein (OMP), a protein expressed in mature ORNs, controls both basal and odorant-induced cAMP levels in an OR-dependent manner. Lack of OMP increases basal cAMP, thus abolishing differences in basal cAMP levels between ORNs expressing different ORs. Moreover, OMP speeds up signal transduction for ORNs to better synchronize their output with high-frequency stimulation and to perceive brief stimuli. Last, OMP also steepens the dose-response relation to improve concentration coding although at the cost of losing responses to weak stimuli. We conclude that OMP plays a key regulatory role in ORN physiology by controlling multiple facets of the odorant response.
SIGNIFICANCE STATEMENT: Odorant receptors (ORs) form the largest family of G-protein-coupled receptors in mammals and are expressed in olfactory receptor neurons (ORNs). In this paper we show how the olfactory system ensures that monogenic expression of ORs dictates the response profile and the basal noise of ORNs. Olfactory marker protein (OMP), a protein long known to be expressed in mature ORNs, is responsible for controlling appropriate cAMP homeostasis and dynamics to ensure that the expressed OR is the main source of noise. In addition, OMP regulates the dynamic range of ORNs in an OR-dependent way to allow for concentration-dependent odor coding.

PMID: 26961953 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaSpj

CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span.

Related Articles

CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span.

Chem Senses. 2015 Jul;40(6):373-9

Authors: Hellekant G, Schmolling J, Marambaud P, Rose-Hellekant TA

Abstract
Stimulation of Type II taste receptor cells (TRCs) with T1R taste receptors causes sweet or umami taste, whereas T2Rs elicit bitter taste. Type II TRCs contain the calcium channel, calcium homeostasis modulator protein 1 (CALHM1), which releases adenosine triphosphate (ATP) transmitter to taste fibers. We have previously demonstrated with chorda tympani nerve recordings and two-bottle preference (TBP) tests that mice with genetically deleted Calhm1 (knockout [KO]) have severely impaired perception of sweet, bitter, and umami compounds, whereas their sour and salty tasting ability is unaltered. Here, we present data from KO mice of effects on glossopharyngeal (NG) nerve responses, TBP, food intake, body weight, and life span. KO mice have no NG response to sweet and a suppressed response to bitter compared with control (wild-type [WT]) mice. KO mice showed some NG response to umami, suggesting that umami taste involves both CALHM1- and non-CALHM1-modulated signals. NG responses to sour and salty were not significantly different between KO and WT mice. Behavioral data conformed in general with the NG data. Adult KO mice consumed less food, weighed significantly less, and lived almost a year longer than WT mice. Taken together, these data demonstrate that sweet taste majorly influences food intake, body weight, and life span.

PMID: 25855639 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhGafr

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

J Neurosci. 2016 Mar 9;36(10):2995-3006

Authors: Dibattista M, Reisert J

Abstract
UNLABELLED: Olfactory receptor neurons (ORNs) in the nasal cavity detect and transduce odorants into action potentials to be conveyed to the olfactory bulb. Odorants are delivered to ORNs via the inhaled air at breathing frequencies that can vary from 2 to 10 Hz in the mouse. Thus olfactory transduction should occur at sufficient speed such that it can accommodate repetitive and frequent stimulation. Activation of odorant receptors (ORs) leads to adenylyl cyclase III activation, cAMP increase, and opening of cyclic nucleotide-gated channels. This makes the kinetic regulation of cAMP one of the important determinants for the response time course. We addressed the dynamic regulation of cAMP during the odorant response and examined how basal levels of cAMP are controlled. The latter is particularly relevant as basal cAMP depends on the basal activity of the expressed OR and thus varies across ORNs. We found that olfactory marker protein (OMP), a protein expressed in mature ORNs, controls both basal and odorant-induced cAMP levels in an OR-dependent manner. Lack of OMP increases basal cAMP, thus abolishing differences in basal cAMP levels between ORNs expressing different ORs. Moreover, OMP speeds up signal transduction for ORNs to better synchronize their output with high-frequency stimulation and to perceive brief stimuli. Last, OMP also steepens the dose-response relation to improve concentration coding although at the cost of losing responses to weak stimuli. We conclude that OMP plays a key regulatory role in ORN physiology by controlling multiple facets of the odorant response.
SIGNIFICANCE STATEMENT: Odorant receptors (ORs) form the largest family of G-protein-coupled receptors in mammals and are expressed in olfactory receptor neurons (ORNs). In this paper we show how the olfactory system ensures that monogenic expression of ORs dictates the response profile and the basal noise of ORNs. Olfactory marker protein (OMP), a protein long known to be expressed in mature ORNs, is responsible for controlling appropriate cAMP homeostasis and dynamics to ensure that the expressed OR is the main source of noise. In addition, OMP regulates the dynamic range of ORNs in an OR-dependent way to allow for concentration-dependent odor coding.

PMID: 26961953 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaSpj

Quinine Bitterness and Grapefruit Liking Associate with Allelic Variants in TAS2R31.

Related Articles

Quinine Bitterness and Grapefruit Liking Associate with Allelic Variants in TAS2R31.

Chem Senses. 2015 Jul;40(6):437-43

Authors: Hayes JE, Feeney EL, Nolden AA, McGeary JE

Abstract
Multiple psychophysical gene-association studies suggest a single nucleotide polymorphism (SNP) within the bitter receptor gene TAS2R19 on chromosome 12 may be functional. Previously, the Arg299Cys SNP (rs10772420) has been associated with differential bitterness of quinine and differential liking for grapefruit juice. However, quinine does not activate TAS2R19 in vitro; likewise, limonin and naringin, bitter compounds in grapefruit, do not activate TAS2R19 in vitro. Here, we examined quinine bitterness (whole-mouth swish-and-spit stimuli and regionally delivered quinine across 4 loci) and remembered liking for grapefruit juice to test whether they associate with SNPs in another nearby gene, TASR2R31. We observed SNP-phenotype associations between whole-mouth quinine bitterness and self-reported liking for grapefruit juice with SNPs in TAS2R31, and regional quinine bitterness followed a similar trend, but did not reach significance. Present data provide independent replication of prior associations reported for TAS2R19. However, we also observed strong linkage disequilibrium (LD) between TAS2R19 and TAS2R31 SNPs. When present data are considered in light of existing functional expression data, this suggests phenotypic associations reported previously for rs10772420 may potentially be due to LD between this SNP and polymorphism(s) in, or closer to, TAS2R31. If confirmed, this would reduce the number of TAS2Rs with putatively functional polymorphisms to 5.

PMID: 26024668 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhG9Iu

Variability in Human Bitter Taste Sensitivity to Chemically Diverse Compounds Can Be Accounted for by Differential TAS2R Activation.

Related Articles

Variability in Human Bitter Taste Sensitivity to Chemically Diverse Compounds Can Be Accounted for by Differential TAS2R Activation.

Chem Senses. 2015 Jul;40(6):427-35

Authors: Roura E, Aldayyani A, Thavaraj P, Prakash S, Greenway D, Thomas WG, Meyerhof W, Roudnitzky N, Foster SR

Abstract
The human population displays high variation in taste perception. Differences in individual taste sensitivity may also impact on nutrient intake and overall appetite. A well-characterized example is the variable perception of bitter compounds such as 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC), which can be accounted for at the molecular level by polymorphic variants in the specific type 2 taste receptor (TAS2R38). This phenotypic variation has been associated with influencing dietary preference and other behaviors, although the generalization of PROP/PTC taster status as a predictor of sensitivity to other tastes is controversial. Here, we proposed that the taste sensitivities of different bitter compounds would be correlated only when they activate the same bitter taste receptor. Thirty-four volunteers were exposed to 8 bitter compounds that were selected based on their potential to activate overlapping and distinct repertoires of TAS2Rs. Taste intensity ratings were evaluated using the general Labeled Magnitude Scale. Our data demonstrate a strong interaction between the intensity for bitter substances when they activate common TAS2Rs. Consequently, PROP/PTC sensitivity was not a reliable predictor of general bitter sensitivity. In addition, our findings provide a novel framework to predict taste sensitivity based on their specific T2R activation profile.

PMID: 25999325 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaPJZ

Temperature Affects Human Sweet Taste via At Least Two Mechanisms.

Related Articles

Temperature Affects Human Sweet Taste via At Least Two Mechanisms.

Chem Senses. 2015 Jul;40(6):391-9

Authors: Green BG, Nachtigal D

Abstract
The reported effects of temperature on sweet taste in humans have generally been small and inconsistent. Here, we describe 3 experiments that follow up a recent finding that cooling from 37 to 21 °C does not reduce the initial sweetness of sucrose but increases sweet taste adaptation. In experiment 1, subjects rated the sweetness of sucrose, glucose, and fructose solutions at 5-41 °C by dipping the tongue tip into the solutions after 0-, 3-, or 10-s pre-exposures to the same solutions or to H2O; experiment 2 compared the effects of temperature on the sweetness of 3 artificial sweeteners (sucralose, aspartame, and saccharin); and experiment 3 employed a flow-controlled gustometer to rule out the possibility the effects of temperature in the preceding experiments were unique to dipping the tongue into a still taste solution. The results (i) confirmed that mild cooling does not attenuate sweetness but can increase sweet taste adaptation; (ii) demonstrated that cooling to 5-12 °C can directly reduce sweetness intensity; and (iii) showed that both effects vary across stimuli. These findings have implications for the TRPM5 hypothesis of thermal effects on sweet taste and raise the possibility that temperature also affects an earlier step in the T1R2-T1R3 transduction cascade.

PMID: 25963040 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhGbjj

Regulatory Effects of Ca2+ and H+ on the Rat Chorda Tympani Response to NaCl and KCl.

Related Articles

Regulatory Effects of Ca2+ and H+ on the Rat Chorda Tympani Response to NaCl and KCl.

Chem Senses. 2015 Jul;40(6):401-12

Authors: DeSimone JA, Phan TH, Mummalaneni S, Rhyu MR, Heck GL, Lyall V

Abstract
Modulatory effects of pHi and [Ca(2+)]i on taste receptor cell (TRC) epithelial sodium channel (ENaC) were investigated by monitoring chorda tympani (CT) responses to NaCl and KCl at various lingual voltages, before and after lingual application of ionomycin and with 0-10mM CaCl2 in the stimulus and rinse solutions adjusted to pHo 2.0-9.7. 0.1 and 0.5M KCl responses varied continuously with voltage and were fitted to an apical ion channel kinetic model using the same parameters. ENaC-dependent NaCl CT response was fitted to the same channel model but with parameters characteristic of ENaC. A graded increase in TRC [Ca(2+)]i decreased the ENaC-dependent NaCl CT response, and inhibited and ultimately eliminated its pH sensitivity. CT responses to KCl were pHi- and [Ca(2+)]i-independent. Between ±60 mV applied lingual potential, the data were well described by a linear approximation to the nonlinear channel equation and yielded 2 parameters, the open-circuit response and the negative of the slope of the line in the CT response versus voltage plot, designated the response conductance. The ENaC-dependent NaCl CT response conductance was a linear function of the open-circuit response for all pHi-[Ca(2+)]i combinations examined. Analysis of these data shows that pHi and [Ca(2+)]i regulate TRC ENaC exclusively through modulation of the maximum CT response.

PMID: 25953775 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaRS4

A Binary Genetic Approach to Characterize TRPM5 Cells in Mice.

Related Articles

A Binary Genetic Approach to Characterize TRPM5 Cells in Mice.

Chem Senses. 2015 Jul;40(6):413-25

Authors: Kusumakshi S, Voigt A, Hübner S, Hermans-Borgmeyer I, Ortalli A, Pyrski M, Dörr J, Zufall F, Flockerzi V, Meyerhof W, Montmayeur JP, Boehm U

Abstract
Transient receptor potential channel subfamily M member 5 (TRPM5) is an important downstream signaling component in a subset of taste receptor cells making it a potential target for taste modulation. Interestingly, TRPM5 has been detected in extra-oral tissues; however, the function of extra-gustatory TRPM5-expressing cells is less well understood. To facilitate visualization and manipulation of TRPM5-expressing cells in mice, we generated a Cre knock-in TRPM5 allele by homologous recombination. We then used the novel TRPM5-IRES-Cre mouse strain to report TRPM5 expression by activating a τGFP transgene. To confirm faithful coexpression of τGFP and TRPM5 we generated and validated a new anti-TRPM5 antiserum enabling us to analyze acute TRPM5 protein expression. τGFP cells were found in taste bud cells of the vallate, foliate, and fungiform papillae as well as in the palate. We also detected TRPM5 expression in several other tissues such as in the septal organ of Masera. Interestingly, in the olfactory epithelium of adult mice acute TRPM5 expression was detected in only one (short microvillar cells) of two cell populations previously reported to express TRPM5. The TRPM5-IC mouse strain described here represents a novel genetic tool and will facilitate the study and tissue-specific manipulation of TRPM5-expressing cells in vivo.

PMID: 25940069 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhG8UP

Characterization of Sensory Properties of Flavanols - A Molecular Dynamic Approach.

Related Articles

Characterization of Sensory Properties of Flavanols - A Molecular Dynamic Approach.

Chem Senses. 2015 Jul;40(6):381-90

Authors: Ferrer-Gallego R, Quijada-Morín N, Brás NF, Gomes P, de Freitas V, Rivas-Gonzalo JC, Escribano-Bailón MT

Abstract
In this work, sensations elicited by catechin and procyanidins in comparison with those elicited by gallocatechin and prodelphinidins were evaluated by means of a sensory panel. To obtain further insights into the mechanisms of action, molecular dynamics (MD) simulations and saturation transfer difference nuclear magnetic resonance (STD NMR) experiments have been performed. Results showed clear differences between the 2 types of flavanols. Dihydroxylated B-ring flavanols were more astringent, bitter, dry, rough, unripe, and persistent than trihydroxylated B-ring ones. Besides, these last compounds were smoother, more velvety, and viscous. MD simulations and STD NMR experiments support results obtained from tasting panel. MD results suggested that catechin binds to a human salivary proline-rich peptide IB714 faster than gallocatechin and this interaction is maintained longer. IB714 can interact with 2 catechin molecules concurrently while only interacts with 1 gallocatechin molecule. Accordingly, STD NMR experiments showed a greater affinity of catechin than gallocatechin for the peptide (K D = 2.7 and 25.7, respectively). Results indicate that the number of hydroxyl substituents present in B-ring of the flavanic nucleus is decisive for the interaction with salivary proteins and the development of astringency perception.

PMID: 25934978 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaPcV

CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span.

Related Articles

CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span.

Chem Senses. 2015 Jul;40(6):373-9

Authors: Hellekant G, Schmolling J, Marambaud P, Rose-Hellekant TA

Abstract
Stimulation of Type II taste receptor cells (TRCs) with T1R taste receptors causes sweet or umami taste, whereas T2Rs elicit bitter taste. Type II TRCs contain the calcium channel, calcium homeostasis modulator protein 1 (CALHM1), which releases adenosine triphosphate (ATP) transmitter to taste fibers. We have previously demonstrated with chorda tympani nerve recordings and two-bottle preference (TBP) tests that mice with genetically deleted Calhm1 (knockout [KO]) have severely impaired perception of sweet, bitter, and umami compounds, whereas their sour and salty tasting ability is unaltered. Here, we present data from KO mice of effects on glossopharyngeal (NG) nerve responses, TBP, food intake, body weight, and life span. KO mice have no NG response to sweet and a suppressed response to bitter compared with control (wild-type [WT]) mice. KO mice showed some NG response to umami, suggesting that umami taste involves both CALHM1- and non-CALHM1-modulated signals. NG responses to sour and salty were not significantly different between KO and WT mice. Behavioral data conformed in general with the NG data. Adult KO mice consumed less food, weighed significantly less, and lived almost a year longer than WT mice. Taken together, these data demonstrate that sweet taste majorly influences food intake, body weight, and life span.

PMID: 25855639 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhGafr

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons.

J Neurosci. 2016 Mar 9;36(10):2995-3006

Authors: Dibattista M, Reisert J

Abstract
UNLABELLED: Olfactory receptor neurons (ORNs) in the nasal cavity detect and transduce odorants into action potentials to be conveyed to the olfactory bulb. Odorants are delivered to ORNs via the inhaled air at breathing frequencies that can vary from 2 to 10 Hz in the mouse. Thus olfactory transduction should occur at sufficient speed such that it can accommodate repetitive and frequent stimulation. Activation of odorant receptors (ORs) leads to adenylyl cyclase III activation, cAMP increase, and opening of cyclic nucleotide-gated channels. This makes the kinetic regulation of cAMP one of the important determinants for the response time course. We addressed the dynamic regulation of cAMP during the odorant response and examined how basal levels of cAMP are controlled. The latter is particularly relevant as basal cAMP depends on the basal activity of the expressed OR and thus varies across ORNs. We found that olfactory marker protein (OMP), a protein expressed in mature ORNs, controls both basal and odorant-induced cAMP levels in an OR-dependent manner. Lack of OMP increases basal cAMP, thus abolishing differences in basal cAMP levels between ORNs expressing different ORs. Moreover, OMP speeds up signal transduction for ORNs to better synchronize their output with high-frequency stimulation and to perceive brief stimuli. Last, OMP also steepens the dose-response relation to improve concentration coding although at the cost of losing responses to weak stimuli. We conclude that OMP plays a key regulatory role in ORN physiology by controlling multiple facets of the odorant response.
SIGNIFICANCE STATEMENT: Odorant receptors (ORs) form the largest family of G-protein-coupled receptors in mammals and are expressed in olfactory receptor neurons (ORNs). In this paper we show how the olfactory system ensures that monogenic expression of ORs dictates the response profile and the basal noise of ORNs. Olfactory marker protein (OMP), a protein long known to be expressed in mature ORNs, is responsible for controlling appropriate cAMP homeostasis and dynamics to ensure that the expressed OR is the main source of noise. In addition, OMP regulates the dynamic range of ORNs in an OR-dependent way to allow for concentration-dependent odor coding.

PMID: 26961953 [PubMed - in process]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaSpj

Quinine Bitterness and Grapefruit Liking Associate with Allelic Variants in TAS2R31.

Related Articles

Quinine Bitterness and Grapefruit Liking Associate with Allelic Variants in TAS2R31.

Chem Senses. 2015 Jul;40(6):437-43

Authors: Hayes JE, Feeney EL, Nolden AA, McGeary JE

Abstract
Multiple psychophysical gene-association studies suggest a single nucleotide polymorphism (SNP) within the bitter receptor gene TAS2R19 on chromosome 12 may be functional. Previously, the Arg299Cys SNP (rs10772420) has been associated with differential bitterness of quinine and differential liking for grapefruit juice. However, quinine does not activate TAS2R19 in vitro; likewise, limonin and naringin, bitter compounds in grapefruit, do not activate TAS2R19 in vitro. Here, we examined quinine bitterness (whole-mouth swish-and-spit stimuli and regionally delivered quinine across 4 loci) and remembered liking for grapefruit juice to test whether they associate with SNPs in another nearby gene, TASR2R31. We observed SNP-phenotype associations between whole-mouth quinine bitterness and self-reported liking for grapefruit juice with SNPs in TAS2R31, and regional quinine bitterness followed a similar trend, but did not reach significance. Present data provide independent replication of prior associations reported for TAS2R19. However, we also observed strong linkage disequilibrium (LD) between TAS2R19 and TAS2R31 SNPs. When present data are considered in light of existing functional expression data, this suggests phenotypic associations reported previously for rs10772420 may potentially be due to LD between this SNP and polymorphism(s) in, or closer to, TAS2R31. If confirmed, this would reduce the number of TAS2Rs with putatively functional polymorphisms to 5.

PMID: 26024668 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhG9Iu

Variability in Human Bitter Taste Sensitivity to Chemically Diverse Compounds Can Be Accounted for by Differential TAS2R Activation.

Related Articles

Variability in Human Bitter Taste Sensitivity to Chemically Diverse Compounds Can Be Accounted for by Differential TAS2R Activation.

Chem Senses. 2015 Jul;40(6):427-35

Authors: Roura E, Aldayyani A, Thavaraj P, Prakash S, Greenway D, Thomas WG, Meyerhof W, Roudnitzky N, Foster SR

Abstract
The human population displays high variation in taste perception. Differences in individual taste sensitivity may also impact on nutrient intake and overall appetite. A well-characterized example is the variable perception of bitter compounds such as 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC), which can be accounted for at the molecular level by polymorphic variants in the specific type 2 taste receptor (TAS2R38). This phenotypic variation has been associated with influencing dietary preference and other behaviors, although the generalization of PROP/PTC taster status as a predictor of sensitivity to other tastes is controversial. Here, we proposed that the taste sensitivities of different bitter compounds would be correlated only when they activate the same bitter taste receptor. Thirty-four volunteers were exposed to 8 bitter compounds that were selected based on their potential to activate overlapping and distinct repertoires of TAS2Rs. Taste intensity ratings were evaluated using the general Labeled Magnitude Scale. Our data demonstrate a strong interaction between the intensity for bitter substances when they activate common TAS2Rs. Consequently, PROP/PTC sensitivity was not a reliable predictor of general bitter sensitivity. In addition, our findings provide a novel framework to predict taste sensitivity based on their specific T2R activation profile.

PMID: 25999325 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaPJZ

Temperature Affects Human Sweet Taste via At Least Two Mechanisms.

Related Articles

Temperature Affects Human Sweet Taste via At Least Two Mechanisms.

Chem Senses. 2015 Jul;40(6):391-9

Authors: Green BG, Nachtigal D

Abstract
The reported effects of temperature on sweet taste in humans have generally been small and inconsistent. Here, we describe 3 experiments that follow up a recent finding that cooling from 37 to 21 °C does not reduce the initial sweetness of sucrose but increases sweet taste adaptation. In experiment 1, subjects rated the sweetness of sucrose, glucose, and fructose solutions at 5-41 °C by dipping the tongue tip into the solutions after 0-, 3-, or 10-s pre-exposures to the same solutions or to H2O; experiment 2 compared the effects of temperature on the sweetness of 3 artificial sweeteners (sucralose, aspartame, and saccharin); and experiment 3 employed a flow-controlled gustometer to rule out the possibility the effects of temperature in the preceding experiments were unique to dipping the tongue into a still taste solution. The results (i) confirmed that mild cooling does not attenuate sweetness but can increase sweet taste adaptation; (ii) demonstrated that cooling to 5-12 °C can directly reduce sweetness intensity; and (iii) showed that both effects vary across stimuli. These findings have implications for the TRPM5 hypothesis of thermal effects on sweet taste and raise the possibility that temperature also affects an earlier step in the T1R2-T1R3 transduction cascade.

PMID: 25963040 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XhGbjj

Regulatory Effects of Ca2+ and H+ on the Rat Chorda Tympani Response to NaCl and KCl.

Related Articles

Regulatory Effects of Ca2+ and H+ on the Rat Chorda Tympani Response to NaCl and KCl.

Chem Senses. 2015 Jul;40(6):401-12

Authors: DeSimone JA, Phan TH, Mummalaneni S, Rhyu MR, Heck GL, Lyall V

Abstract
Modulatory effects of pHi and [Ca(2+)]i on taste receptor cell (TRC) epithelial sodium channel (ENaC) were investigated by monitoring chorda tympani (CT) responses to NaCl and KCl at various lingual voltages, before and after lingual application of ionomycin and with 0-10mM CaCl2 in the stimulus and rinse solutions adjusted to pHo 2.0-9.7. 0.1 and 0.5M KCl responses varied continuously with voltage and were fitted to an apical ion channel kinetic model using the same parameters. ENaC-dependent NaCl CT response was fitted to the same channel model but with parameters characteristic of ENaC. A graded increase in TRC [Ca(2+)]i decreased the ENaC-dependent NaCl CT response, and inhibited and ultimately eliminated its pH sensitivity. CT responses to KCl were pHi- and [Ca(2+)]i-independent. Between ±60 mV applied lingual potential, the data were well described by a linear approximation to the nonlinear channel equation and yielded 2 parameters, the open-circuit response and the negative of the slope of the line in the CT response versus voltage plot, designated the response conductance. The ENaC-dependent NaCl CT response conductance was a linear function of the open-circuit response for all pHi-[Ca(2+)]i combinations examined. Analysis of these data shows that pHi and [Ca(2+)]i regulate TRC ENaC exclusively through modulation of the maximum CT response.

PMID: 25953775 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1pBaRS4