The neuroethology of feeding in jellyfish

1.1.为了鉴定控制摄食的神经元，我们在水母中使用磷酸化MAPK抗体染色。通常，当神经元激发动作电位时，钙流入细胞，引起MAPK/ERK信号通路的激活，这反过来触发MAPK磷酸化为磷酸化MAPK（pMAPK）。因此，通过用pMAPK抗体染色整个水母，我们可以鉴定活化的神经元。为了证明这种方法有效，我们用光刺激水母，并将pMAPK染色与保持在黑暗中的水母进行比较。这导致水母眼睛周围的神经元染色强烈，但仅限于暴露在光线下的动物。这证明抗pMAPK染色可用于标记水母中的活性神经元。不幸的是，当我们使用其他感觉方式时，例如化学或机械刺激，我们无法识别出一个清晰的模式。水母摄食相关基因的鉴定为了更好地了解水母摄食调控相关基因，我们对饥饿和进食的动物进行了RNA分析。通过这种方式，我们能够识别出数百种基因，这些基因在水母饥饿或饱足时表达量更高。我们的假设是，这些基因中的一些可能参与调节水母的食欲。利用生物信息学方法，我们能够识别出在其他动物的食欲调节中也起作用的潜在保守基因。

1.1. Neuronal activity mapping in the jellyfishTo identify neurons controlling feeding, we used phospho-MAPK antibody staining in the jellyfish. Typically, when a neuron fires an action potential, calcium flows into the cell, causing activation of the MAPK/ERK signaling pathway, which in turn triggers MAPK phosphorylation into phospho-MAPK (pMAPK). Thus, by staining whole jellyfish eith a pMAPK antibody, we can identify activated neurons. To prove that this approach works, we stimulated jellyfish with light and compared the pMAPK staining with jellyfish which remained in darkness. This resulted in strong staining of the neurons around the jellyfish eyes, but only for the animals that were exposed to light. This proves that anti-pMAPK staining can be used for labeling active neurons in jellyfish. Unfortunately, we were unable to identify a clear pattern when we used other sensory modalities, such as chemical or mechanical stimulation.1.2. Identification of genes involved in jellyfish feedingTo better understand the genes involved in the regulation of jellyfish feeding, we carried out RNA analyses in hungry and fed animals. In this way, we were able to identify hundreds of genes that become more highly expressed when the jellyfish is hungry or full. Our hypothesis is that some of these genes may be involved in the regulation of appetite in jellyfish. Using bioinformatics approaches, we were able to identify potentially conserved genes that also play a role in appetite regulation in other animals.