ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Meiotic activity in the öcytes of the starfish, Asterias forbesi, may be blocked by immersion in deuterated sea water (60% or more) as is judged by a stoppage in the breakdown of the germinal vesicles and a failure of the cells to form persistent polar bodies. These anti-meiotic effects of heavy water were reversed in significant degree by application of suitable intensities (3,000 to 6,000 psi) of hydrostatic pressure. In this regard meiosis resembles mitosis, as studied previously in the first cleavage division of the sea urchin, Strongylocentrotus purpuratus.In studying germinal vesicle breakdown, immersion of the öcytes in deuterated (60, 70 and 80% D2O) sea water was initiated ten minutes after shedding and pressurization was established six minutes later. None of the non-pressurized deuterated cells showed complete breakdown of the germinal vesicle, whereas complete breakdown was observed in a significant percentage of the pressurized deuterated specimen.In studying their capacity to form and maintain polar bodies, the öcytes were deuterated 60 minutes after shedding and pressurized six minutes later. Maximum release from deuterational blockage, as judged by the percentage of persistent polar bodies after one hour of treatment, was as follows: 85% at 2,000 psi for 50% D2O; 65% at 2,500 psi, for 60%; 77% at 3,000 psi for 70%; 55% at 3,500 psi for 80% and 65% at 3,500 psi for 90%. Persistence of polar bodies in the non-pressurized deuterated cells did not exceed 15% in any medium containing 60% or more of D2O and the average persistence in such media was only 2.5%.Basic mechanisms which may account for the observed effects are discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1040670103
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