Umami taste-yielding foods, such as, Joseonganjang, dried anchovies, dried shiitake, dried Konbu (kelp), and Yukjeot, are widely used in the Korean cuisine as soup base. While Umami taste enhancement related to Kokumi taste substances has been proposed in human sensory studies, the potential action of Kokumi taste substances has not been explored on calcium-sensing receptors (CaSR), here referred to as Kokumi taste receptors. In this study, we investigated the effect of Umami taste-yielding foods on Kokumi taste receptors using cells expressing human CaSR. We monitored the temporal changes in intracellular Ca2+ in HEK293T cells expressing CaSR in response to aqueous extract of Joseonganjang, dried anchovies, dried shiitake, dried Konbu, and Yukjeot. Kokumi substances tested-glutathione and γ-Glu-Val-Gly- evoked intracellular Ca2+ influx in a concentration-dependent manner. A similar increment of intracellular Ca2+ influx was induced by Joseonganjang, Yukjeot, and dried anchovies, but not by dried shiitake and dried Konbu. Only Joseonganjang- and Yukjeot-evoked intracellular Ca2+ influx was significantly reduced by NPS 2143, a CaSR-specific antagonist. These data indicated that some Umami substances/Umami-yielding materials could activate CaSR, but this property was not observed for all the Umami tasting substances.

밥맛은 밥쌀용 쌀 품종의 품질을 평가하는 중요한 항목 중 하나로, 훈련된 패널을 활용하여 평가하고 있다. 본 연구는 밥맛 평가의 정밀도 향상을 위하여 전자혀의 일종인 taste sensing system을 이용하여 관능적 식미 특성이 다른 쌀 10 품종의 밥맛을 측정하여 분석하였다. 분석 결과, taste sensor를 이용한 밥맛 측정은 밥의 쓴맛, 감칠맛, 단맛 측정에 적합한 것으로 나타났고 감칠맛의 경우, 관능적 평가에서 밥맛이 좋게 평가되었던 삼광의 측정값이 가장 높았고, 관능적 평가에서 밥맛이 나쁘게 평가되었던 한아름은 가장 낮은 측정값을 보였으며 품종간의 값 차이는 유의성이 인정되었다. 이러한 결과는 taste sensor를 밥맛 측정에 활용할 수 있다는 가능성을 보여주며, taste sensing system을 본격적으로 밥맛 측정에 활용하기 위해서는 다양한 조합을 통한 상관 분석이 필요할 것으로 생각된다.

Although it is believed that internal nutrient sensors play important roles in feeding behaviors, their molecular and neural mechanisms underlying of the modulation of physiological status and cell growth are poorly understood. Using a Ca2+ imaging experiments with heterologous expression systems, we show that one of the gustatory receptors in the western honey bee Apis mellifera is selectively tuned to amino acids. Remarkably, we report that this gustatory receptor of the honey bee is highly expressed in hypopharyngeal gland, which plays a role in caste differentiation as well as royal jelly production and secretion. Knocking down this gustatory receptor gene reduces cellular pathways responsible for nutritional sensing such as mTOR signals in hypopharageal gland. Furthermore, the interfering expression of this gustatory receptor gene not only alters morphological changes and developmental retardation of the hypopharyngeal gland, but it also blocks cellular growth signals to induce autophagy. This new report indicates that internal sensing and downstream signals detecting nutrients is essential for honey bee to maintain the cellular growth and development of internal organs essential for caste development and maintenance of social structure in the honey bee.