FIGURE 6.

Pulse labeling of wild type and dga1Δlro1Δare1Δare2Δ with ³²[P]orthophosphate. Cultures were grown in I⁺C⁺ medium at 37 °C until mid-logarithmic phase of growth (A₆₀₀ = 0. 5) and then divided in half. One half of the culture was filtered, washed in pre-warmed I⁺C⁺, and resuspended in the same medium, whereas the remaining half was filtered-washed with prewarmed I⁻C⁺ medium and resuspended in I⁻C⁺. Both cultures were incubated at 37 °C, and samples were collected at 1.5 and 3 h and pulse-labeled for 20 min with ³²P. Lipids were extracted and analyzed as described under “Experimental Procedures.” Data are expressed as counts of radiolabel ³²P incorporated into total and individual phospholipids per absorbance units in the cell culture. PE, phosphatidylethanolamine; Total PL, total phospholipids. The inset on each of the panels is an expansion of the data that accounts for PI, PA, and CDP-DAG. Panel A, shown are cultures harvested at 1.5 h after the shift to I⁻C⁺ at 37 °C. Panel B, shown are samples harvested at 3 h after the shift to I⁻C⁺ at 37 °C. Panel C, shown are samples taken at 3 h after the shift to I⁺C⁺ at 37 °C. Solid bars represent wild type cells, and open bars indicate dga1Δlro1Δare1Δare2Δ.