A scalable culturing system for the marine annelid Platynereis dumerilii

Abstract

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.

Small-molecule mimicry hunting strategy in the imperial cone snail, Conus imperialis

“…S6). Thus, the feeding biology of C. imperialis is more complex than previously recorded ( 24 – 26 ).…”

“…Thus, a model system was required. P. dumerilii is one of the few polychaete model systems used in biological research ( 24 ), and it is consumed by worm-hunting cones ( 25 , 26 ). To determine whether P. dumerilii would provide a suitable model, we reinvestigated this question using a validated polymerase chain reaction (PCR) approach that has been recently applied to worm-hunting cones ( 26 ).…”

The Nereid on the rise: Platynereis as a model system

“…Current laboratory cultures of P. dumerilii , which range in scale from a few hundred to tens of thousands of worms per culture, all trace back to the initial culture established by Carl Hauenschild in the 1950s, and originate from the Bay of Naples (Italy) with sporadic in-crossing from other locations such as Arcachon [ 21 , 22 ]. Laboratory culture techniques were more recently improved [ 40 , 41 ].…”

“…For wild-type strains, lab colony sizes can be as small as 500–1000 worms at a time (Hird et al, unpublished). Based on the number of mature animals needed, it is easy to scale up or down P. dumerilii cultures [ 41 ]. While practices vary across labs, the worms typically can be cultured in food-safe, non-reactive plastic containers with 500–1500 mL sea water.…”

“…However, recent efforts to develop new culturing methods solely based on artificial seawater from commercially available sea salt mixes have proven successful (Hird et al , unpublished). In addition, progress has been made on standardizing and improving feeding, such as spirulina powder instead of spinach for juveniles [ 41 ] and using algae cocktails and live feeds for faster larval settlement and early development, respectively (Hird et al, unpublished). One of the critical future advances will be developing and improving cryopreservation methods for larvae or sperm for maintaining and sharing transgenic or mutant strains [ 42 ].…”