Molecular Biology Section, Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi, Japan.
Sci Rep. 2016 Dec 16;6:39352. doi: 10.1038/srep39352.
Taste sensitivity differs among animal species depending on feeding habitat. To humans, sucrose is one of the sweetest natural sugars, and this trait is expected to be similar in other primates. However, previous behavioral tests have shown that some primate species have equal preferences for maltose and sucrose. Because sweet tastes are recognized when compounds bind to the sweet taste receptor Tas1R2/Tas1R3, we evaluated the responses of human and Japanese macaque Tas1R2/Tas1R3 to various natural sugars using a heterologous expression system. Human Tas1R2/Tas1R3 showed high sensitivity to sucrose, as expected; however, Japanese macaque Tas1R2/Tas1R3 showed equally high sensitivity to maltose and sucrose. Furthermore, Japanese macaques showed equally high sensitivity to sucrose and maltose in a two-bottle behavioral experiment. These results indicate that Japanese macaques have high sensitivity to maltose, and this sensitivity is directly related to Tas1R2/Tas1R3 function. This is the first molecular biological evidence that for some primate species, sucrose is not the most preferable natural sugar, as it is for humans.
味觉敏感度因动物物种的摄食生境而异。对于人类来说，蔗糖是最甜的天然糖之一，其他灵长类动物也应该具有类似的特性。然而，之前的行为测试表明，一些灵长类物种对麦芽糖和蔗糖具有同等的偏好。因为当化合物与甜味受体 Tas1R2/Tas1R3 结合时，甜味就会被识别出来，所以我们使用异源表达系统评估了人类和日本猕猴 Tas1R2/Tas1R3 对各种天然糖的反应。正如预期的那样，人类 Tas1R2/Tas1R3 对蔗糖表现出很高的敏感性；然而，日本猕猴 Tas1R2/Tas1R3 对麦芽糖和蔗糖的敏感性同样高。此外，在双瓶行为实验中，日本猕猴对蔗糖和麦芽糖表现出同样高的敏感性。这些结果表明，日本猕猴对麦芽糖具有很高的敏感性，这种敏感性与 Tas1R2/Tas1R3 的功能直接相关。这是第一个分子生物学证据，证明对于某些灵长类动物来说，蔗糖并不是最受欢迎的天然糖，就像人类一样。
