The Ceramidase Inhibitor, Carmofur, Significantly Disrupts Reproduction In Daphnia Magna

Daniel Arega

School Name

Governor's School for Science and Math

Grade Level

12th Grade

Presentation Topic

Microbiology

Presentation Type

Mentored

Mentor

Mentor: Dr. Baldwin; Department of Toxicology, Clemson University

Abstract

Sphingomyelinase converts sphingomyelin to ceramide and ceramidase converts ceramide to sphingosine. We used inhibitors of these enzymes to determine the potential role of ceramide and sphingosine in Daphnia magna. We used the ceramidase inhibitor, Carmofur that blocks sphingosine production and the sphingomyelinase inhibitor, GW4869 that blocks ceramide production in toxicity tests. The daphnids were exposed to different concentrations of the toxicants in order to determine their effects on reproduction. We hypothesized that both inhibitors will significantly decrease reproduction in D. magna. We ran 48-hour acute toxicity tests on < 24 hour old D. magna. Concentrations up to 1000 µg/L of GW4869 caused no toxicity, and only the 1000 µg/L concentration decreased survival in the Carmofur group (50%). We also performed 21-day chronic toxicity tests to study the effect of these chemicals on survival and reproduction. Unexposed daphnids reproduced at 8 days old, but 100 and 200µg/L Carmofur-exposed daphnids did not reproduce until 15 days old. GW4869 did not have observable effects. The expression of ceramidase and sphingomyelinase genes in D. magna at 2, 4, 7 and 14 days old through Polymerase Chain Reaction (PCR) were also assessed. The results showed that the ceramidase gene was highly expressed in grown daphnids capable of reproduction (Zheng, 2012).

Location

Owens 110

Start Date

4-16-2016 8:45 AM

COinS
 
Apr 16th, 8:45 AM

The Ceramidase Inhibitor, Carmofur, Significantly Disrupts Reproduction In Daphnia Magna

Owens 110

Sphingomyelinase converts sphingomyelin to ceramide and ceramidase converts ceramide to sphingosine. We used inhibitors of these enzymes to determine the potential role of ceramide and sphingosine in Daphnia magna. We used the ceramidase inhibitor, Carmofur that blocks sphingosine production and the sphingomyelinase inhibitor, GW4869 that blocks ceramide production in toxicity tests. The daphnids were exposed to different concentrations of the toxicants in order to determine their effects on reproduction. We hypothesized that both inhibitors will significantly decrease reproduction in D. magna. We ran 48-hour acute toxicity tests on < 24 hour old D. magna. Concentrations up to 1000 µg/L of GW4869 caused no toxicity, and only the 1000 µg/L concentration decreased survival in the Carmofur group (50%). We also performed 21-day chronic toxicity tests to study the effect of these chemicals on survival and reproduction. Unexposed daphnids reproduced at 8 days old, but 100 and 200µg/L Carmofur-exposed daphnids did not reproduce until 15 days old. GW4869 did not have observable effects. The expression of ceramidase and sphingomyelinase genes in D. magna at 2, 4, 7 and 14 days old through Polymerase Chain Reaction (PCR) were also assessed. The results showed that the ceramidase gene was highly expressed in grown daphnids capable of reproduction (Zheng, 2012).