20 mM taurine, 20 mM HEPES, 1.0 g/l BSA, pH 7.1) at a concentration of 3-56106 cells/ml. Cells were incubated with 1 mg/mL LPS for 4 h. Respiration rates were measured at 37uC in a high-resolution oxygraph (Oxygraph-2k, Oroboros Instruments, Innsbruck, Austria). For assessment of mitochondrial complex activity cells were first permeabilized with digitonin (8.1 mM) for 5 min. Afterwards, for complex I-dependent maximal respiration stimulation, substrates added were glutamate (10 mM) and malate (5 mM), followed by addition of adenosine diphosphate (ADP) (0.25 mM) causing a sudden burst of oxygen uptake as ADP is converted into ATP. After a stable signal was reached and marked, rotenone (0.5 mM) was added to inhibit complex I, and then complex II-dependent respiration was stimulated by adding succinate (10 mM), while complex III was inhibited by antimycin A (0.5 mM) (Sigma Aldrich, Buchs, Switzerland). 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PLoS ONE | www.plosone.org 11 June 2010 | Volume 5 | Issue 6 | e10983