The taste of D- and L-amino acids: In vitro binding assays with cloned human bitter (TAS2Rs) and sweet (TAS1R2/TAS1R3) receptors

Bassoli, Angela; Borgonovo, Gigliola; Caremoli, Filippo; Mancuso, Giuseppe

doi:10.1016/j.foodchem.2013.10.106

Cited by 71 publications

(53 citation statements)

References 16 publications

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“…In S1, S2, and S3, the major FAAs were Pro (sweet), Thr, and His (bitter), while Glu (fresh, sour), Pro, and Trp (bitter) were predominant in S4 and S5. Because FAAs have been shown to be associated with different tastes (Bassoli et al, 2014), these results suggested that the taste of the milk base fermented by L. casei GBHM-21 obviously affected when the fat content was increased to a certain extent, i.e., up to 60 g·L −1 in our study. FAAs can also be converted via a variety of pathways due to the catalytic activity of enzymes, contributing to malty, fruity, and sweet flavors (Ardö, 2006;Fox, Singh, & McSweeney, 1995).…”

Section: Faasmentioning

confidence: 48%

“…Additionally, lipolysis leads to the formation of free fatty acids (FFAs) and their oxidation products such as ketones, and therefore contributes to the development of a favored fermented aroma (Hassan, Mona, et al, 2013). Meanwhile, proteolysis leads to the production of free amino acids (FAAs), which are crucial for the characteristic taste of fermented milk and also are important precursors in the synthesis of essential volatile compounds (Bassoli, Borgonovo, Caremoli, & Mancuso, 2014;Mikulec, Habuš, Antunac, Vitale, & Havranek, 2010). However, the interrelation among the concentrations of these flavor-related compounds is relatively less studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Profiles of free fatty acids, free amino acids, and volatile compounds of milk bases fermented byLactobacillus caseiGBHM-21 with different fat levels

Bao¹,

Xiong²,

Lin³

et al. 2015

CyTA - Journal of Food

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Milk fat content is an important factor affecting the flavor of fermented dairy products. The effects of milk fat concentration (0-90) g·L −1 on the changes of flavor-related compounds in the milk base fermented by Lactobacillus casei GBHM-21 were investigated. The amount of some of the free fatty acids (FFAs) and free amino acids (FFAs) increased as the fat concentration increased, accompanied by a concomitant increase of the quantities and intensities of volatile compounds (VCs). A substantial increase in long-chain fatty acids was observed, whereas no significant effect on short-chain fatty acids was observed. The amount of the total FFA was linearly and positively correlated with the total FAA. The most abundant group of VCs was ketones for low-fat samples and carbonyl acids for high-fat samples. The level of FFA-derived ketones increased dramatically first and then reached a plateau, while FFA-derived carbonyl acids continuously increased. These results provided valuable informative utilization of milk fat in the fermented industry.Keywords: fermented milk base; free fatty acid; free amino acid; volatile compound; Lactobacillus casei El nivel de grasa en la leche es un factor importante en el sabor de los productos lácteos fermentados. Se investigaron los efectos del nivel de grasa en la leche (0-90 g·L −1 ) en los cambios en los compuestos relacionados con el sabor en bases de leche fermentadas con Lactobacillus casei GBHM-21 durante 72 h. Los ácidos no grasos (FFA) y los aminoácidos no grasos (FAA) de forma selectiva, además de la calidad e intensidad de los compuestos volátiles (VC) aumentaron significativamente con el aumento de la concentración de grasa. No se observó ningún efecto significativo en los ácidos grasos de cadena corta, mientras que sí se observó un aumento sustancial en los ácidos grasos de cadena larga. Se encontró que la relación positiva entre el total de ácidos no grasos y aminoácidos no grasos era lineal. El grupo más abundante de compuestos volátiles resultó ser las cetonas para las muestras bajas en grasa, mientras que los ácidos carbonilos para las muestras altas en grasa. El aumento en las cetonas derivadas de ácidos no grasos primero fue dramático y después cónico, mientras que el aumento en los ácidos carbonilos derivados de ácidos no grasos fue lineal. Estos resultados resultarían útiles para una mayor expansión de las aplicaciones de la grasa en la industria de la fermentación.

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Section: Faasmentioning

confidence: 48%

Section: Introductionmentioning

confidence: 99%

Profiles of free fatty acids, free amino acids, and volatile compounds of milk bases fermented byLactobacillus caseiGBHM-21 with different fat levels

Bao¹,

Xiong²,

Lin³

et al. 2015

CyTA - Journal of Food

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“…CLQ is an agonist of TAS2Rs and has been shown to activate several TAS2Rs, including TAS2R3, TAS2R7, TAS2R10, and TAS2R39 [19-21]. We showed that CLQ did not exhibit any effects on the base tone of human DSM strips.…”

Section: Resultsmentioning

confidence: 66%

Activation of bitter taste receptors (tas2rs) relaxes detrusor smooth muscle and suppresses overactive bladder symptoms

et al. 2016

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Bitter taste receptors (TAS2Rs) are traditionally thought to be expressed exclusively on the taste buds of the tongue. However, accumulating evidence has indicated that this receptor family performs non-gustatory functions outside the mouth in addition to taste. Here, we examined the role of TAS2Rs in human and mouse detrusor smooth muscle (DSM). We showed that mRNA for various TAS2R subtypes was expressed in both human and mouse detrusor smooth muscle (DSM) at distinct levels. Chloroquine (CLQ), an agonist for TAS2Rs, concentration-dependently relaxed carbachol- and KCl-induced contractions of human DSM strips. Moreover, 100 μM of CLQ significantly inhibited spontaneous and electrical field stimulation (EFS)-induced contractions of human DSM strips. After a slight contraction, CLQ (1 mM) entirely relaxed carbachol-induced contraction of mouse DSM strips. Furthermore, denatonium and quinine concentration-dependently decreased carbachol-induced contractions of mouse DSM strips. Finally, we demonstrated that CLQ treatment significantly suppressed the overactive bladder (OAB) symptoms of mice with partial bladder outlet obstruction (PBOO). In conclusion, we for the first time provide evidence of the existence of TAS2Rs in the urinary DSM and demonstrate that TAS2Rs may represent a potential target for OAB. These findings open a new approach to develop drugs for OAB in the future.

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“…Although this hypothesis requires further validation, another mechanism by which airway T1R2/3 receptors may be activated is through bacterial production of D-amino acids, several of which activate the sweet taste receptor (26, 33). Life has evolved to predominately utilize L-amino acids as protein building blocks, but bacteria produce a diverse array of D-amino acids used as cell wall structural components and possibly intercellular signals.…”

Section: Introductionmentioning

confidence: 99%

“…This range is predicted to be sufficient to activate the sweet taste receptor (33, 53) on the airway epithelial SCCs that produce T1R2/3. We hypothesize that certain D-amino acids produced by bacteria may play an important role in host-pathogen interactions in the sinonasal cavity by activating the sweet taste receptor in SCCs, and thus we sought to study the effects of sweet-receptor–activating D-amino acids on upper respiratory epithelial cells and on the physiology of respiratory bacteria.…”

Section: Introductionmentioning

confidence: 99%

Bacterial d -amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells

et al. 2017

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In the upper respiratory epithelium, bitter and sweet taste receptors present in solitary chemosensory cells influence antimicrobial innate immune defense responses. Whereas activation of the bitter taste receptor (T2R) stimulates surrounding epithelial cells to release antimicrobial peptides, activation of the sweet taste receptor (T1R) in the same cells inhibits this response. It is thought that this mechanism exists to control the magnitude of antimicrobial peptide release based upon the sugar content of airway surface liquid. We hypothesized that D-amino acids, which are produced by various bacteria and activate T1R in taste receptor cells in the mouth, may also activate T1R in the airway. Here, we show that both the T1R2 and T1R3 subunits of the sweet taste receptor (T1R2/3) are present in the same chemosensory cells of primary human sinonasal epithelial cultures. Respiratory isolates of Staphylococcus species, but not Pseudomonas aeruginosa, produced at least two D-amino acids that activate the sweet taste receptor. In addition to inhibiting P. aeruginosa biofilm formation, D-amino acids derived from Staphylococcus inhibited T2R-mediated signaling and defensin secretion in sinonasal cells by activating T1R2/3. D-amino acid–mediated activation of T1R2/3 also enhanced epithelial cell death during challenge with Staphylococcus aureus in the presence of the bitter-receptor–activating compound denatonium benzoate. These data establish a potential mechanism for interkingdom signaling in the airway mediated by bacterial D-amino acids and the mammalian sweet taste receptor in airway chemosensory cells.

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The taste of D- and L-amino acids: In vitro binding assays with cloned human bitter (TAS2Rs) and sweet (TAS1R2/TAS1R3) receptors

Cited by 71 publications

References 16 publications

Profiles of free fatty acids, free amino acids, and volatile compounds of milk bases fermented byLactobacillus caseiGBHM-21 with different fat levels

Profiles of free fatty acids, free amino acids, and volatile compounds of milk bases fermented byLactobacillus caseiGBHM-21 with different fat levels

Activation of bitter taste receptors (tas2rs) relaxes detrusor smooth muscle and suppresses overactive bladder symptoms

Bacterial d -amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells

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