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1′-Acetoxychavicol acetate (ACA) is found in Thai ginger (Alpinia galanga) and is a powerful agonist of transient receptor potential ankyrin 1 (TRPA1). In a diet-induced obesity mouse model, ACA reduced fat deposition. Sympathetic nerve activation was also indicated in the ACA-fed group. This study is expected to promote the utilization of food containing TRPA1 agonists to treat obesity. [ABSTRACT FROM AUTHOR]

Many functional food ingredients activate human bitter taste receptors (hTAS2Rs). In this study, A novel inhibitor, Trp-Trp, for hTAS2R14 was identified by searching for the agonist peptide's analogs. Trp-Trp also inhibited hTAS2R16, hTAS2R43, and hTAS2R46, which share the same agonists with hTAS2R14. The multifunctional characteristic of Trp-Trp is advantageous for use as bitterness-masking agents in functional foods. [ABSTRACT FROM AUTHOR]

Humans sense taste and smell of various chemical substances through approximately 430 chemosensory receptors. The overall picture of ligand–chemosensory receptor interactions has been partially clarified because of numerous interactions. This study presents a new method that enables a rapid and simple screening of chemosensory receptors. It would be useful for identifying chemosensory receptors activated by taste and odor substances. [ABSTRACT FROM AUTHOR]

The uptake of di/tripeptides is mediated by the proton-dependent oligopeptide transporter (POT) family. In this study, 3 POT family transporters, designated PotA, PotB, and PotC were identified in Aspergillus oryzae. Growth comparison of deletion mutants of these transporter genes suggested that PotB and PotC are responsible for di/tripeptide uptake. PotA, which had the highest sequence similarity to yeast POT (Ptr2), contributed little to the uptake. Nitrogen starvation induced potB and potC expression, but not potA expression. When 3 dipeptides were provided as nitrogen sources, the expression profiles of these genes were different. PrtR, a transcription factor that regulates proteolytic genes, was involved in regulation of potA and potB but not in potC expression. Only potC expression levels were dramatically reduced by disruption of ubrA , an orthologue of yeast ubiquitin ligase UBR1 responsible for PTR2 expression. Expression of individual POT genes is apparently controlled by different regulatory mechanisms. [ABSTRACT FROM AUTHOR]

γ-glutamyl peptides have been suggested to impart kokumi properties to foods by activating human calcium-sensing receptor (hCaSR). In this study, the relationship between γ-glutamyl peptide structure and hCaSR activity was systematically analyzed using γ-[Glu](n=0-4)-α-[Glu](n=0-3)-Tyr. Our results suggest that N-terminal [Glu]3 moiety is very important for hCaSR activities of γ-glutamyl peptides. [ABSTRACT FROM AUTHOR]

Daidai (bitter orange, Citrus aurantium) is characterized by its fresh citrus scent. In Japanese cuisine, its juice is an important ingredient. As tons of industrial waste is obtained while processing the daidai juice, additional utilization of this waste has great social value. In our study, we prepared the essential oil from the waste obtained during daidai juice processing and demonstrated that the oil activates human TRPA1 (hTRPA1). This oil contains 10 types of terpenes, all of which activated hTRPA1 with an EC50 value of 6–167 µM. To our knowledge, this study is the first to show a hTRPA1 activation by five terpenes: linalyl acetate, geranyl acetate, osthole, geranyl propionate, and neryl acetate. Because physiological benefits of TRPA1 agonists, such as enhancement of energy metabolism and promotion of skin barrier recovery, have been reported, the oil could be a promising ingredient for anti-obesity food products and cosmetics. Graphical Abstract Human TRPA1 activation by terpenes contained in the peel of daidai. [ABSTRACT FROM AUTHOR]

Tangeretin and nobiletin are polymethoxylated flavonoids in citrus peel. Both tangeretin and nobiletin are bitter; however, their bitterness has not been evaluated using human bitter taste receptors (hTAS2Rs). We screened 25 kinds of hTAS2Rs and found that hTAS2R14 and hTAS2R46 received both compounds. [ABSTRACT FROM PUBLISHER]

The article discusses a study on improvement of Saccharomyces cerevisiae yeast cells growth during the exponential phase by the addition of soy peptides to the media. It mentions an increment in growth and expression levels of six of the G proteins coupled receptors by an average of 2.3 fold when compared against the free amino acid based medium. The main factor involved in enhanced protein expression is by alleviation of metabolite stress because of amino acid source depletion.

The article presents a study on the structural change and test-modifying activity in neoculin depending on the pH levels. It states that neoculin is a protein that contains sweetness and shows taste-modifying activity like converting sourness to sweetness. The study determined that the structural changes in neoculin is reversible depending on the pH levels. Moreover, the study adds that one can repeatedly sense the sweet taste by taking acidic solution within 30 minutes.

The article presents a study on the induction of non-acidic compounds on the sweetness of neoculin, a taste-modifying protein. The study used solutions of sodium acetate buffer at different concentrations at the same pH and an intrinsic tryptophan (Trp) fluorescence spectroscopic analysis to determine the structure of neoculin changes. Results showed that ammonium chloride and amino acids serine (Ser), cysteine (Cys), and threonine (Thr) can induce the intense sweetness of neoculin.