解析和研究活体水平辐射旁效应及其作用机制对于低剂量辐射防护和肿瘤治疗具有重要的意义。神经酰胺（Ceramide），作为细胞内脂质的第二信使，已被报道与细胞水平辐射损伤信号的产生和传导有重要的关联。利用单粒子定点精确照射系统和突变体遗传学的方法，我们前期研究显示神经酰胺可能参与了线虫活体辐射旁效应信号在体细胞和生殖细胞的传导。本项目将在此基础上，利用特定分子探针、线虫RNA干涉技术和突变品系，深入探讨精确定点照射对线虫体内神经酰胺表达和分布的影响，研究神经酰胺上下游代谢和激活途径影响辐射旁效应的空间作用过程和相关信号通路，初步明确损伤信号从体细胞到生殖细胞的调控过程和分子机制，为辐射防护和肿瘤治疗提供可供参考的实验数据和理论依据。

The radiation-induced bystander effect in vivo (RIBE) is very significant for the healthy risk assessment at low doses, as well as cancer therapy. Ceramide, as the second message in the cell, has been reported to have the close relationship with radiation induced bystander effects. Using single particle microbeam and molecular genetic method, our previous study showed that Ceramide might involve in the signal transduction of RIBE from somatic cells to germ cells in the model animal C.elegans after the proton microbeam irradiation of pharynx. In the present study, we will further investigate the levels and distribution of Ceramide in C.elegans, the effects of radiation on the metabolism of Ceramide, the downstream pathways of Cermaide involving in the spatial processes of signals in C.elegans, using the methods of microbeam, RNAi and molecular probes etc. These results are expected to clarify the regulation procedures and molecular mechanisms of ceramid and its downstream signaling pathways to the RIBE in C.elegans.