Lipids play essential roles in cell-structuring, cell-signaling, and as efficient metabolic energy stores. Lipid storage capacities determine life history traits of organisms and, thus, their ecological function. Among storage lipids, triacylglycerols (TAGs) are widespread in marine invertebrates. However, abilities to accumulate TAGs can vary even between closely related species, such as the caridean shrimps Crangon crangon and Pandalus montagui. The first species shows low TAG levels throughout the year in the main storage organ, the midgut gland, while the latter accumulates high TAG-levels, peaking in summer. TAGs synthesis is facilitated by the terminal step of the Kennedy-pathway, where the enzyme diacylglycerol-acyltransferase (DGAT) catalyzes the esterification of diacylglycerols with activated fatty acids. We investigated DGAT activity in the midgut gland using a fluorescent enzyme assay. Sequence information was extracted from whole transcriptome shotgun assembly data, that was publicly available on NCBI, and catalytic properties were deduced from molecular structure analysis. C. crangon showed significantly lower TAG synthesis rates than P. montagui, which explains the native TAG levels. Transcriptome data yielded several isoforms of DGAT enzymes in both species. C. crangon DGAT showed point mutations, which are capable of obstructing the catalytic capacity. The consequences are limited starvation resistance and, thus, presumably restricting C. crangon to a habitat with year-round sufficient food. In contrast, higher TAG synthesis rates presumably enable P. montagui to extend into northern subarctic habitats with limited food availability in winter. Moreover, the limited TAG synthesis and accumulation in the midgut gland may force C. crangon to direct energy into the ovaries, which results in multiple spawnings.

脂质在细胞结构、细胞信号传导和有效的代谢能量储存中发挥着重要作用。脂质储存能力决定生物体的生命史特征，从而决定其生态功能。在储存脂质中，三酰甘油（TAG）广泛存在于海洋无脊椎动物中。然而，即使在密切相关的物种之间，积累标签的能力也可能有所不同，例如加勒比虾Crangon crangon和Pandalus montagui。第一个物种在主要储存器官中肠腺中全年显示出较低的 TAG 水平，而后者则积累了较高的 TAG 水平，在夏季达到顶峰。肯尼迪途径的末端步骤促进了 TAG 的合成，其中二酰甘油酰基转移酶 (DGAT) 催化二酰甘油与活化脂肪酸的酯化反应。我们使用荧光酶测定研究了中肠腺中的 DGAT 活性。序列信息是从 NCBI 上公开的全转录组鸟枪组装数据中提取的，并从分子结构分析中推断出催化特性。C. crangon显示出明显低于P. montagui 的TAG 合成率，这解释了天然 TAG 水平。转录组数据在这两个物种中产生了几种 DGAT 酶亚型。C. crangon DGAT 显示点​​突变，能够阻碍催化能力。其后果是抗饥饿能力有限，因此可能将Crangon限制在全年食物充足的栖息地。相比之下，较高的 TAG 合成率可能使P. montagui能够扩展到冬季食物供应有限的北亚北极栖息地。此外，中肠腺中有限的 TAG 合成和积累可能会迫使C. crangon将能量引导至卵巢，从而导致多次产卵。