Végétalisation de l'œuf de l'oursinParacentrotus lividus par l'hydrazide de l'acide isonicotinique (isoniazide)

Summary Isonicotinic acid hydrazide (isoniazid) causes vegetalization of whole larvae of the sea urchinParacentrotus lividus. The effects of isoniazid are compared with those of chloramphenicol and lithium ions. The protein synthesis during the phase of reversible determination, i.e. to the late blastula stage, appears to be of paramount importance in the differentiation of larvae. It is suggested that the protein synthesis connected with the determination of ectodermal structures is more sensitive to the action of vegetalizing agents than the protein synthesis connected with the determination of entomesodermal structures.