Table 2. Fatty acid composition of isogenic C. elegans strains of varying lifespan.

(N.B.: double-mutant control strains had values close to N2, and are not shown here although included for calculation of correlation coefficients.)

FA amounts are indicated as percents of total FAs. Longevity was assessed at least twice per strain, with the results as indicated in Table 1, column 3. For rank-order correlations, strains with median lifespans near the value of wild-type N2DRM (relative median lifespans near 1), were assigned the same longevity rank, since they could not be ordered unambiguously with respect to one another. These strains were the control strain N2DRM, the double-mutant control strains SR818 [daf-16(m26); daf-2(e1370)], SR819 [daf-16(m26); age-1(hx546)] and SR820 [daf-16(m26); age-1(mg44)], and SR803 [old-1(zls3000)]. In these analyses, N is the total number of biological replicates. For each correlation coefficient R, calculated from N data points, its P value was ascertained from its t-transformation, t = |R| · [(N – 2) / (1 – R²)]^½, treating the result as coming from a t distribution with N–2 degrees of freedom.

Average Chain Length, ACL=[(Σ[%14C]×14) + (Σ[%15C]×15) + (Σ[%16C]×16) + (Σ[%17C]×17) + (Σ[%18C]×18) + (Σ[%20C]×20) + (Σ[%22C]×22)]/100, where sums Σ are for all fatty acid chains of the indicated length (14C, 15C, 16C etc.).

(Σ[%22C]×22)]/100, where sums Σ are for all fatty acid chains of the indicated length (14C, 15C, 16C etc.).

Double Bond Index, DBI = (Σ[%nC:1] × 1) + (Σ[%nC:2] × 2) + (Σ[%nC:3] × 3) + (Σ[%nC:4] × 4) + (Σ[%nC:5] × 5), where Σ is for n=12–22.

Peroxidation Index, PI = (Σ[% nC:1] × 0.025) + (Σ[% nC:2] × 1) + (Σ[% nC:3] × 2) + (Σ[% nC:4] × 4) + (Σ[% nC:5] × 6), taking Σ for n=12–22.