Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Max Planck School Matter to Life, 69120 Heidelberg, Germany.
Mar Drugs. 2022 Feb 2;20(2):119. doi: 10.3390/md20020119.
Patellamides are highly bioactive compounds found along with other cyanobactins in the symbiosis between didemnid ascidians and the enigmatic cyanobacterium . The biosynthetic pathway of patellamide synthesis is well understood, the relevant operons have been identified in the genome and genes involved in patellamide synthesis are among the most highly transcribed cyanobacterial genes in hospite. However, a more detailed study of the in vivo dynamics of patellamides and their function in the ascidian- symbiosis is complicated by the fact that remains uncultivated despite numerous attempts since its discovery in 1975. A major challenge is to account for the highly dynamic microenvironmental conditions experienced by in hospite, where light-dark cycles drive rapid shifts between hyperoxia and anoxia as well as pH variations from pH ~6 to ~10. Recently, work on patellamide analogues has pointed out a range of different catalytic functions of patellamide that could prove essential for the ascidian- symbiosis and could be modulated by the strong microenvironmental dynamics. Here, we review fundamental properties of patellamides and their occurrence and dynamics in vitro and in vivo. We discuss possible functions of patellamides in the ascidian- symbiosis and identify important knowledge gaps and needs for further experimental studies.
栉水母肽是高度生物活性的化合物，与神秘的蓝细菌共生在Didemnid 海鞘中其他氰基化合物一起发现。栉水母肽合成的生物合成途径已经很好理解，相关的操纵子已经在基因组中被识别，并且参与栉水母肽合成的基因是宿主中转录水平最高的蓝细菌基因之一。然而，由于自 1975 年发现以来，尽管进行了多次尝试，但仍然无法培养，因此对栉水母肽在体内的动态及其在海鞘共生体中的功能进行更详细的研究变得复杂。一个主要的挑战是要解释宿主中经历的高度动态微环境条件，其中光暗循环导致超氧和缺氧之间的快速转换以及 pH 值从 pH6 到 pH10 的变化。最近，关于栉水母肽类似物的研究指出了栉水母肽的一系列不同的催化功能，这些功能可能对海鞘共生体至关重要，并且可以通过强烈的微环境动态进行调节。在这里，我们回顾了栉水母肽的基本特性及其在体外和体内的存在和动态。我们讨论了栉水母肽在海鞘共生体中的可能功能，并确定了进一步实验研究的重要知识差距和需求。
