Worm Breeder's Gazette 10(2): 115
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
The tumor promoting phorbol ester TPA causes severe perturbations in the growth and reproduction of larval and adult C. elegans. One g/ml of TPA arrests the growth of L1 larvae. We reported previously that the partial embryo that comprised an AB or a P1 cell underwent many rounds of cell division to form cell clusters and that E-cell specific autofluorescence developed normally in a P1-derived partial embryo in 1 g/ml of TPA. Thus, we concluded that C. elegans early embryogenesis was unaffected by TPA. The observations have been confirmed in the presence of 5 g/ml TPA using laser microsurgery. We have, however, remained unable to tell whether the late embryogenesis is also unaffected by TPA, because gastrulation and morphogenesis do not proceed normally in the partial embryo. In an attempt to solve this problem, we used laser microsurgery to puncture an eggshell without causing apparent damages in individual cells. We punctured the eggshell of two-cell stage embryos with laser microbeam (wave length 560nm, about 1 m diameter at the focal plane, pulsed beam of 6ns duration) in the embryonic culture medium and followed the embryonic development. To insure that an effective hole was opened at the egg shell, a nontoxic fluorescent dye, 0.1% lucifer yellow, was added to the culture medium. All laser-treated embryos underwent many rounds of cell division in the absence of TPA. Although many stopped developing probably at the beginning of morphogenesis, about 10% of the treated embryos completed morphogenesis and hatched. Hatchees stained with lucifer yellow assured that an effective hole had been made in the eggshell. Some hatchees stained with lucifer yellow were observed even in the presence of 10 g/ml TPA. Muscle differentiation was also investigated in both the presence and the absence of TPA. Laser-treated embryos were cultured and stained with anti-myosin monoclonal antibody. As expected from the above experiment, myosin was stained in the presence of 10 g/ml TPA just as in its absence. These results suggest that TPA has little or no effect on C. elegans embryogenesis.