Fig 1. Diverse environmental stress conditions increase steady state apoptotic corpses in the germline.

(A) Diagram of a single hermaphrodite gonad arm. Germ cells are born in the germ stem cell niche (Mitotic Zone). As they are displaced by the proliferation of germ cells in this region, they exit the niche, enter the Transition Zone and commit to meiosis. In late pachytene, a subset of germ cells undergoes physiological apoptosis while others begin to grow larger as they are provisioned via cytoplasmic streaming from the rachis and receptor-mediated endocytosis from the pseudocoelom [10, 17]. As meiosis 1 completes, large oocytes form a line, enter the spermatheca one at a time during ovulation, and are fertilized. Fertilized embryos develop in the uterus until they are laid. (B) A fluorescent micrograph of the germline loop region of an adult hermaphrodite (L4+24h) in control conditions. The arrow indicates an apoptotic corpse expressing CED-1::GFP. Scale bar: 20μm. (C-D) Number of germ cell corpses per gonad arm after (C) acid (HCl) or oxidative stress (paraquat) exposure, and (D) starvation or (E) ethanol exposure. Black bars indicate estimated marginal means +/- standard error. (* p = 0.01–0.05, ** p = 0.001–0.01, *** p < 0.001; comparisons are all to control for each condition). For statistical models (negative binomial regression) and results, see S1 Table.