Lectin coated colloidal gold as a marker for mesoderm formation in mammalian embryos, cultured in vitro

A simple in vitro culture system for mammalian embryos of pre-somite to 30-somite stages is described, in which mouse and rat embryos are used. The rat embryo culture turned out to be more successful for periods longer than 8 hr. The formation of mesoderm and mesectoderm was studied in these embryos by labeling the primitive streak and neural crest with lectin-coated colloidal gold, that was injected into the amniotic cavity with a micro-injection system.