Biological rhythms in the beach amphipod Talitrus saltator

所有生物，从细菌到人类都有生物钟，使他们能够与周围环境保持时间，这就是我们人类每天大约在同一时间醒来的原因！值得注意的是，这些通常在动物大脑中发现的内部计时机制，即使在有机体与昼夜循环等线索分离的情况下，也会继续工作。生物钟非常重要，因为生物体可以在一天中最合适的时间提前为活动、生长、交配和其他必要的活动做好准备，以躲避捕食者、寻找食物或配偶。因此，它们对所有生物的生存和成功做出了重大贡献。我们现在知道，已经研究过的不同植物和动物的生物钟机制在驱动它们的分子上有着惊人的相似之处，但是，我们的大部分理解都来自于对极少数“模式生物”的研究，比如果蝇。果蝇和几乎所有陆生生物一样，利用昼夜的光循环来使它们的生物钟与当地条件同步。因此，它们的节律性行为和生理以大约24小时为周期重复。然而，海洋植物和动物暴露在许多不同的周期事件中，如潮汐的进出（潮汐时钟，每12.4小时），潮汐周期（潮汐高度周期，12.8小时），甚至潮汐的变化（春潮和小潮）是由月球和太阳的引力引起的（半月时钟，14天）。虽然众所周知，许多海洋物种根据这些不同的事件来调整它们的行为和生理，但我们对它们的生物钟是如何工作的知之甚少。例如，它们是否有与日常时钟相同的分子“齿轮”，但以不同的速度“运行”，或者它们是否有专用的“潮汐”、“月球”或“半月”时钟？本项目将破译沙蚤（Talitrus saltator）循环行为的遗传和生化基础。在英国，这种小甲壳类动物晚上从沙子里的洞穴里出来觅食。夜晚，它沿着地平线的光亮在海岸上下航行，但就在黎明前，它又转过身来，被陆地的黑暗所吸引。沙跳虫的出现和对光/暗的偏好是受时钟控制的，即使它们被人工地保持在完全黑暗的环境中，它们也会继续表现出来。在地中海，同一物种以不同的方式航行——利用太阳和月亮的位置作为它们的向导。这还需要时间感，因为当地球旋转时，太阳和月亮似乎在天空中移动，跳沙鸟必须补偿这一点，以保持航向。我将把英国的跳沙者与地中海的跳沙者进行比较，以确定他们的生物钟是否不同，甚至他们的大脑中是否有多个时钟。这项工作的结果可能会对我们对生物钟的理解产生重要影响，它们如何进化和适应当前的环境条件，它们如何促进生物体的成功以及它们与其他物种的相互作用。

All living things, from bacteria to humans have biological 'clocks' that enable them to keep time with their surrounding environment which is how we humans tend to wake up at roughly the same time each day! Remarkably, these internal timing mechanisms, which are normally found in the brains of animals, continue to work even when the organism is separated from cues, such as cycles of night and day. Biological clocks are extremely important because organisms can prepare in advance for bouts of activity, growth, mating and other necessary activity at the most appropriate part of the day to avoid predators, find food or mates. Therefore they contribute significantly to the survival and success of all organisms. We now know that the clock mechanisms in different plants and animals that have been studied share striking similarities in the molecules that drive them but, most of our understanding comes from work on a very few 'model organisms' such as the fruit fly. The fruit fly, and nearly all terrestrial organisms, uses the night and day light cycles to synchronise their clocks to local conditions. Consequently their rhythmic behaviour and physiology recurs on a cycle of about 24h. However, marine plants and animals are exposed to many different cyclic events such as the tide coming in and out (tidal clocks; every 12.4h), lunidian (cycles of tidal height; 12.8h) and even changes in tidal range (spring and neap tides) caused by the gravitational pull of the moon and the sun (semilunar clocks; 14d). Although it is well known that many marine species time their behaviour and physiology to these different events, we know very little about their how their internal clocks work. For instance, do they have the same molecular 'cogs' as daily clocks but 'run' at a different speed, or do they have dedicated 'tidal', 'lunidian' or 'semilunar' clocks? This project will decipher the genetic and biochemical basis of cyclic behaviours in the sand-hopper, Talitrus saltator. In the UK this small crustacean emerges from its burrow in the sand at night to feed. It navigates up and down the shore by moving towards the light of the sea horizon in the night but just before dawn it turns back and is drawn to the dark of the land. The emergence and light/dark preferences of the sand-hopper are under clock control and continue to be expressed even if they are kept artificially in total darkness. In the Mediterranean the same species navigate in a different way- by using the position of the sun and moon as their guide. This must also require a sense of time because as the Earth rotates, the sun and the moon appear to move across the sky and the sand-hopper must compensate for this to keep on course. I will compare the UK sand-hoppers to those of the Mediterranean to determine whether their clocks are geared differently or even if they have multiple clocks in their brains. The outcomes of this work could have important impacts on our understanding of biological clocks, how they have evolved and adapted to suit the prevailing environmental conditions and how they contribute to the success of the organism and their interactions with other species.