A scalable culturing system for the marine annelid Platynereis dumerilii

Platynereis dumerilii is a marine segmented worm (annelid) with externally fertilized embryos and it can be cultured for the full life cycle in the laboratory. The accessibility of embryos and larvae combined with the breadth of the established molecular and functional techniques has made P. dumerilii an attractive model for studying development, cell lineages, cell type evolution, reproduction, regeneration, the nervous system, and behavior. Traditionally, these worms have been kept in rooms dedicated for their culture. This allows for the regulation of temperature and light cycles, which is critical to synchronizing sexual maturation. However, regulating the conditions of a whole room has limitations, especially if experiments require being able to change culturing conditions. Here we present scalable and flexible culture methods that provide ability to control the environmental conditions, and have a multi-purpose culture space. We provide a closed setup shelving design with proper light conditions necessary for P. dumerilii to mature. We also implemented a standardized method of feeding P. dumerilii cultures with powdered spirulina which relieves the ambiguity associated with using frozen spinach, and helps standardize nutrition conditions across experiments and across different labs. By using these methods, we were able to raise mature P. dumerilii, capable of spawning and producing viable embryos for experimentation and replenishing culture populations. These methods will allow for the further accessibility of P. dumerilii as a model system, and they can be adapted for other aquatic organisms.

杜氏阔沙蚕（Platynereis dumerilii）是一种体外受精的海洋分节环节动物（annelid），可在实验室中完成全生命周期的培养。其胚胎与幼虫易于获取，加之成熟分子与功能技术手段的广泛应用，使其成为研究发育、细胞谱系、细胞类型演化、生殖、再生、神经系统及行为的极具吸引力的模型生物。传统上，这类蠕虫需饲养于专用隔间内，以便调控温度与光照周期——这对同步其性成熟至关重要。但整室环境调控存在局限，尤其当实验需要灵活调整培养条件时。本研究报道了一套可扩展且灵活的培养方法，可精准调控环境参数，并打造多用途培养空间。我们设计了封闭式置物架装置，配置杜氏阔沙蚕成熟所需的适宜光照条件；同时建立了以螺旋藻粉为饲料的标准化饲养流程，规避了使用冷冻菠菜带来的操作歧义，有助于统一不同实验及不同实验室间的营养条件。采用上述方法，我们成功培养出可产卵并产生可用实验胚胎的成熟杜氏阔沙蚕，且可实现培养种群的持续补充。本方法将进一步提升杜氏阔沙蚕作为模型系统的可及性，同时可适配其他水生生物的培养需求。