DEVELOPMENTAL MODIFICATIONS IN ARBACIA PUNCTULATA BY VARIOUS METABOLIC SUBSTANCES

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Abstract
The developmental effect of a series of substances, added to fertilized eggs at minimal concentrations necessary to elicit a morphological response was evaluated. Alcohol (ethyl and methyl) as solvent must be below 1% to prevent effects. The fertilization membrane may be removed by papain, trypsin, or pronase (0.25 mg/ml), the latter also reducing cortical consistency. Sodium taurocholate (2 mg/ml) is lethal at the blastula; at 12.5 [mu]g/ml, 4-nitroquinoline N-oxide arrests cleavage at the morula. Actinomycin D, in aqueous solution, is effective at low doses; at 5 [mu]g/ml survival is poor beyond the blastula; at 2 [mu]g/ml plutei show poor arm formation and persistent fertilization membranes. Persistent fertilization membranes as well as retardation of growth occur in thalidomide suspensions (0.1 mg/ml). Cobalt glycine (0.02 mg/ml), like cobalt chloride, produces irreversible, bizarre exogastrulae (vegetalization) and miniaturization of spicules. Mescaline (0.1 mg/ml) caused retarded plutei with no spicule formation. At 0.1 mg/ml plus 4 [mu]g/ml RNA there was an irreversible block at gastrulation. Coumarin (0.5 mg/ml) produced a developmental block at the blastula with malformations. No amelioration of the inhibiting effect of thymine (0.04 to 0.2 mg/ml) was evident with DNA, DN-ase, or RH-ase. At concentrations below 0.03 mg/ml RNA, 0.05 mg/ml RNA, 8 [mu]g/ml DN-ase, or 0.05 mg/ml RN-ase, development resembled that of the controls; at concentrations above, the effects were retardant and eventually lethal. Attempts were made to reverse the effects by the addition of nucleic acids and their enzymes.