Spica, Patrick et al. (2015) International Worm Meeting "The Effects of Wrapping NGM Culture Plates with Parafilm M® on the Growth and Development of Caenorhabditis elegans."

Scanga, Sara, Spica, Patrick, Shinn-Thomas, Jessica, Klempic, Emra

[International Worm Meeting, 2015]

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 M® during experiments are unknown. Parafilm M® 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 M® may produce a hypoxic (low oxygen) environment compared to plates with no Parafilm M® (normoxic). Anoxic (no oxygen) and hypoxic conditions have been shown to change the metabolism, development, and longevity of C. elegans.Our research aims to determine the effects of wrapping NGM culture plates with Parafilm M® on C. elegans. We hypothesized that worms cultured on plates wrapped in Parafilm M® would exhibit a slower rate of larval growth and increased mortality 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 M®. BD GasPaks™ were used to create anoxic and hypoxic environments, and normoxic culture conditions consisted of unsealed plates. Larval growth rate and mortality were measured 5 times over 48 hours. We found no significant difference in the growth rate between worms cultured in normoxic conditions and on plates wrapped with Parafilm M®. However, the growth rate between worms cultured on plates wrapped with Parafilm M® and worms in anoxic and hypoxic conditions was significantly higher. Mortality was significantly higher in worms cultured in anoxic conditions, but was not significantly different among the other three environmental conditions. Our data suggest that wrapping C. elegans culture plates one time with Parafilm M® does not affect the larval growth rate or viability. Future studies will focus on additional biological and life history metrics, such as fecundity and lifespan, to verify that wrapping with Parafilm M® has no unexpected effects on the outcomes of C. elegans studies.

Hasanspahic, Bilal et al. (2017) International Worm Meeting "An investigation of nontarget insecticide effects of erythritol on C. elegans and two common agricultural crop plants."

Hasanspahic, Bilal, Zvornicanin, Edin, Scanga, Sara, Shinn-Thomas, Jessica, Rahme, Andrew, Samardzic, Jasmina

[International Worm Meeting, 2017]

Sugar substitutes, such as Truvia registered , are increasingly gaining popularity in cooking and processed foods. Erythritol, a non-nutritive polyol, is the main component of Truvia. Previous studies showed that erythritol consumption does not affect plasma and urine osmolarity and electrolyte levels and it is not toxic or carcinogenic to rats. In contrast, erythritol was shown to significantly decrease longevity in Drosophila melanogaster compared to sucrose and other polyols with the exception of D-mannitol. Researchers have suggested that erythritol has potential use as an insecticide given its apparent safety for mammals but harmful effects on arthropods such as Drosophila. However, for erythritol to have practical use as an environmentally-friendly insecticide in agricultural settings, it must have neutral to positive effects on crop plants and other nontarget organisms, including soil and compost-dwelling animals such as C. elegans. The purpose of our research is to examine the dose-dependent, nontarget effects of erythritol on C. elegans lifespan and larval survival, and tomato (Solanum lycopersicum) and corn (Zea mays) germination and growth.

Sara Vassalli et al. (2006) European Worm Meeting "Identification of Genes required for Anchor Cell Attachment and Invasion during Vulval Development"

ALEX HAJNAL, Sara Vassalli

[European Worm Meeting, 2006]

Sara Vassalli and Alex Hajnal. During vulval development in the hermaphrodite, three out of six equivalent vulval precursor cells (the VPCs P3.p to P8.p) are induced by a signal from the gonadal anchor cell (AC). The LIN-3 EGF growth factor produced by the AC activates the EGFR/RAS/MAPK pathway in the VPCs to specify the primary cell fate. Prior to vulval induction, the gonad is separated from the VPCs by two basal laminas covering each tissue such that the position of the AC relative to the VPCs is variable when the animal moves. At the time of vulval induction in the early L3 stage, however, the AC attaches to the basal side of the future primary cell P6.p. After the first round of vulval cell divisions (Pn.px stage), the basal laminas separating the gonad from the vulval cells start to dissolve precisely under the AC. After the second round of divisions (Pn.pxx stage), the basal laminas between the AC and the four primary vulval cells are interrupted, and the AC invades the vulval tissue.. While the mechanism of vulval induction is well studied, less is known about genes regulating the attachment of the AC to P6.p and the following invasion step. To study these two processes, we performed a forward genetic screen for mutants with defects in AC positioning and/or invasion. Since worms with an abnormal or missing connection between the gonad and the vulva usually display a protruding vulva (Pvl) phenotype, we first screened for animals with a Pvl phenotype and then examined them for defects in the positioning or invasion of the AC. Among 5300 F1 clones, we identified 8 sterile mutants with a misplaced AC and 2 mutants, in which the AC is normally positioned but fails to dissolve the basal laminas and invade the vulval tissue. Details about the cloning and analysis of the genes identified in this screen will be presented at the meeting.