FIG. 5.

Effects of polyunsaturated fatty acids on cell death and pigment oxidation. Cells of desA mutant strain PR6080 containing no polyunsaturated fatty acids (14) were grown at 38°C in medium A-U with 1% (vol/vol) CO₂ in air, and the culture (OD₅₅₀, ∼1.0) was divided into five equal aliquots. The aliquots were incubated under the same growth conditions overnight with no addition (lane 1), with 0.1% (vol/vol) methanol (lane 2), with 18:1 (9) fatty acid (lane 3), with 18:2 (9, 12) fatty acid (lane 4), or with 18:3 (9, 12, 15) fatty acid (lane 5). The calculated final concentration of free fatty acids was 0.5 mM. Cells in lanes 4 and 5 were killed and completely bleached of all pigmentation.