For example, when gastrulating
embryos are treated with LiCl, they develop reduced notochords and enhanced vegetal structures, but when treatments are given at earlier or later cleavage stages, dorsalizing and anteriorizing effects, respectively, are observed (3, 9).
Changes in the morphology of gastrulating embryos were quantified.
Gastrulating embryos were fixed with 1% glutaraldehyde dissolved in MFSW at room temperature for 2 h.
Gastrulating embryos were fixed successively with cold methanol and ethanol (-20[degrees]C), 20 mm in each.
A micropipette was used to attach the gastrulating embryos to the bottom of the glass dish; in some cases, the embryos were pressed against the bottom of the dish with a fine glass needle, to ensure attachment.
To test this possibility, the change in the length of the archenteron was monitored in gastrulating embryos attached to a glass dish coated with poly-L-lysine.