Patrick S. Spica, Emra Klempic, Sara E. Scanga, Jessica H. Shinn-Thomas. The Effects of Wrapping NGM Culture Plates with Parafilm M® on the Growth and Development of Caenorhabditis elegans. Poster Presentation at International C. elegans Meeting, Los Angeles, CA.
Parafilm M® is a thin thermoplastic used to seal a variety of containers in scientific laboratories. It is commonly used to seal Nematode Growth Media (NGM) culture plates to prevent microbial contamination and media dehydration. However, the effects on C. elegans of wrapping culture plates with Parafilm during experiments are unknown. Parafilm may limit gas exchange between the external and culture environment, potentially affecting the biology and life history of C. elegans, including its larval growth rate, viability, fecundity, lifespan, and behavior. In particular, wrapping culture plates with Parafilm may produce a hypoxic (low oxygen) environment compared to plates with no Parafilm (normoxic). Anoxic (no oxygen) and hypoxic conditions have shown to change the metabolism, development, and longevity of C. elegans (Hajeri et al., 2005; Leiser et al., 2013; Mendenhall et al., 2006; Powell-Coffman, 2010; Zhang et al., 2009).
Our research aims to determine the effects of wrapping NGM culture plates with Parafilm on C. elegans. We hypothesized that worms cultured on plates wrapped in Parafilm would exhibit a slower larval growth and decreased survival compared to worms grown in normoxic conditions. Synchronized L1 worms were individually transferred to culture plates and incubated within an anoxic environment, hypoxic environment, normoxic environment, or wrapped one time with Parafilm. Larval growth was measured 5 times over 48 hours and viability was measured at the conclusion of the treatments after 24 hours under normoxic conditions. We found no significant difference in larval growth rate among worms cultured in plates under conditions of normoxia, hypoxia, or wrapped with Parafilm. However, larval growth was significantly slower for worms grown in anoxic conditions compared to the other three environmental conditions. Survival was significantly lower in worms cultured in anoxic conditions, but was not significantly different among the other three environmental conditions. Our results suggest that wrapping C. elegans culture plates one time with Parafilm does not affect larval growth rate or viability. Future studies will focus on additional biological and life history metrics, such as lifespan, to verify that wrapping with Parafilm has no unexpected effects on the outcomes of C. elegans studies.