Figure 2.

Measurement of sphingolipids after treatment with bacterial sphingomyelinase. Macrophages (J774.1) were treated with either 250 or 500 mU/ml bacterial sphingomyelinase (bSMase). Monolayers were then washed and subject to lipid extraction. Lipid extracts were then analyzed using LC-coupled MS and normalized to protein found in the cell extract using the Bradford assay. A, sphingomyelin (SM) species in the treated samples are shown (n = 3). B, ceramide (Cer) species in the treated samples are shown (n = 3). Error bars represent the SEM, and statistical significance was determined using ANOVA with Tukey's multiple comparisons test. Not significant (ns), ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.005, and ∗∗∗∗p < 0.0001 compared with the untreated control. All p values were adjusted for multiplicity.