Fig. 1. DMPP is lethal at the L2/L3 molt and induces aberrant L3 cuticle
synthesis. (A) Fraction of wild-type larvae reaching adulthood when
grown on increasing concentrations of DMPP (n
50 worms).
Experiments were performed at 20°C. (B) Representative example of
an animal exposed to 0.75 mM DMPP which dies as an early L3 larvae, just after
shedding the L2 cuticle (arrow). Scale bar: 0.1 mm. (C-E) Electron
microscopy (EM) pictures after chemical fixation of young L3 larvae. Scale
bar: 5 µm. Worms grown on DMPP (D,E) have irregular shapes when compared
with the control (C). (F,G) Electron microscopy pictures of
young L3 larvae cuticle after high-pressure freezing fixation. Scale bar: 250
nm. (F) Control animals grown on standard plates show a typical mono-layered
L3 cuticle (Cut) covering a thin epidermis (Ep) and underlying body-wall
muscles (Mus). (G) Animals grown on DMPP have an aberrant L3 cuticle with
several layers of heterogeneous aspects and fibrillar structures (arrow).