CAFFEINE EFFECTS ON FERTILIZATION AND DEVELOPMENT IN ARBACIA PUNCTULATA

¹ Biology Department, Brooklyn College, and The Marine Biological Laboratory, Woods Hole, Mass.

1. Caffeine does affect the gametes and the zygotes development of Arbacia punctulata.

2. Pre-treatment of both gametes with caffeine (0.5 per cent or higher) prior to mixing for fertilization and developed in CSW prevents the separation of the fertilization membrane.

3. Since some development occurs if both gametes are caffeinized but developed in SW, the FM may form but not be separated from the egg mass in the case of CSW as the environment.

4. The results of gamete activity following immersion and subsequent fertilization and development in CSW suggest that the egg is somewhat more sensitive than the sperm to caffeine.

5. Minimum effective concentrations in general are 0.1 per cent CSW (M/200). Slight retardation of development in 0.02 per cent CSW, under conditions of C x N and development in SW, is noted.

6. Oxygen uptake inhibition effect of caffeine is a primary factor in the retardation of cleavage time.

7. Early cleavage stages are retarded most.

8. The inhibition of O₂ utilization, retardation of cleavage time, and the degree of interference with the symmetrical differentiation attained, are directly proportional to the caffeine concentrations.

9. Concentrations of 0.5 per cent CSW (M/40) or higher as an environmental medium inhibit completely the physiological processes underlying the mechanics of further differentiation.

10. Caffeine does not initiate an osmotic effect with regard to the transport of water into the Arbacia egg.

11. Other factors in the explanation of the results observed are suggested.