Another bioactive sphingolipid, CER, results from either the degradation of SM by sphingomyelinases or de novo synthesis through the condensation of palmitate and serine [32, 34] . These lipids were preferentially up regulated in DENV-infected cells at both the 36 and 60 hr time points (,2-fold compared to the mock). Since SM was also up regulated similarly in DENV infected cells, the rise in CER is possibly the result of de novo synthesis rather than SM degradation. UV-DENV-exposed cells showed undetectable CER levels at 36 hr, while at 60 hr the expression was (,2 fold) above the mock control. Since there was a concurrent decrease in SM in UV-DENV exposed cells at 60 hr, the increased levels of CER in this case could be due to the degradation of SM resulting from increased cellular stress (resulting from incubation of the cells for 60 hr). Similar to other lipid species, CER also showed temporal regulation depending on the molecular species expressed ( Figure 3F ).