Cyclo（delta-Ala-L-Val）是由δ-丙氨酸和缬氨酸融合形成的二酮哌嗪，据报道是真菌和细菌的次生代谢产物。在铜绿假单胞菌中，环（delta-Ala-L-Val）能够激活N-酰基高丝氨酸内酯（AHLs）。Cyclo（delta-Ala-L-Val）还能够激活或拮抗其他基于LuxR的群体感应系统。虽然环（delta-Ala-L-Val）的作用方式尚不清楚，但其活性表明细菌信号系统之间存在串扰。 Cyclo(delta-Ala-L-Val) is a diketopiperazine formed by the fusion of delta-alanine and valine which has been reported as a secondary metabolite of fungi and bacteria. In Pseudomonas aeruginosa, cyclo(delta-Ala-L-Val) is capable of activating N-acylhomoserine lactones (AHLs). Cyclo(delta-Ala-L-Val) is also capable of activating or antagonizing other LuxR-based quorum-sensing systems. While the mode of action of cyclo(delta-Ala-L-Val) is not known, its activity suggests the existence of cross talk among bacterial signalling systems.