The daily rhythm of PERIOD (PER) protein expression is an integral component of the circadian clock, which is found among a broad range of animal species including fruit flies, marine mollusks, and even humans. The use of antibodies directed against PER has provided a helpful tool in the discovery of PER homologs and the labeling of putative pacemaker cells, especially in animals for which an annotated genome is not readily available. In this study, Drosophila-PER antibodies were used to probe for PER in the American lobster, Homarus americanus. This species exhibits robust endogenous circadian rhythms but the circadian clock has yet to be located or characterized. PER was detected in the eyestalks of the lobster but not in the brain. Furthermore, a significant effect of the light/dark cycle on daily PER abundance was identified, and PER was significantly more abundant at mid-dark than in early light or mid-light hours. Our results suggest that PER is a part of the molecular machinery of the circadian clock located in the eyestalk of the lobster.

中文翻译：

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美洲龙虾眼柄中 PERIOD 蛋白的日常节律

PERIOD (PER) 蛋白表达的日常节律是生物钟的一个组成部分，它存在于包括果蝇、海洋软体动物甚至人类在内的广泛动物物种中。使用针对 PER 的抗体为发现 PER 同源物和标记假定的起搏器细胞提供了有用的工具，尤其是在不易获得注释基因组的动物中。在这项研究中，果蝇-PER 抗体用于探测美洲龙虾 Homarus americanus 中的 PER。该物种表现出强大的内源性昼夜节律，但尚未定位或表征生物钟。在龙虾的眼柄中检测到 PER，但在大脑中未检测到。此外，还确定了光/暗循环对每日 PER 丰度的显着影响，PER 在中暗时明显多于早亮或中光时。我们的结果表明 PER 是位于龙虾眼柄中的生物钟分子机制的一部分。