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This study concerned changes in the motional properties of cellular water during the first cell cycle of fertilized sea urchin eggs (Lytechinus variegatus). There was a significant decrease in proton NMR T1 relaxation time and in cytoplasmic ice crystal growth during mitosis and a significant increase in T1 time and cytoplasmic ice crystal size during cleavage. This was not caused by egg water content changes as reflected by egg volume measurements. Removal of both the fertilization membrane and the hyaline layer shortly after fertilization did not alter the pattern of T1 time changes at mitosis and cleavage as compared to whole eggs; thus, the pattern of T1 time changes was attributed to intracellular events. Treatment of fertilized eggs with cytochalasin B, an inhibitor of actin polymerization, did not block the fall in T1 time at mitosis, but did block cytokinesis and the increase in T1 time, which normally occurred at cleavage. A significant pattern of actin disassembly and reassembly at mitosis and cytokinesis was found by studies on the total amount of monomeric actin (G actin) using the DNase I assay. This led to the hypothesis that the observed changes in T1 time and ice crystal size during the first cell cycle were due to the depolymerization and polymerization of cytoplasmic actin. To test this, the effect of the in vitro polymerization of purified actin on the T1 time and on ice crystal growth was examined. It was concluded that changes in the T1 time and ice crystal growth upon polymerization of actin in vitro resembled the changes seen in vivo. These results suggest that changes in the motional properties of cytoplasmic water during the first cell cycle are due, at least in part, to the state of polymerization of cytoplasmic actin.
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1970,
Biorheology,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1966,
Tsitologiia,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
May 1984,
Experimental cell research,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
October 1979,
European journal of cell biology,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1977,
Biochemical Society transactions,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
October 1963,
Experimental cell research,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1985,
Development, growth & differentiation,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1985,
Development, growth & differentiation,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1990,
Journal of reproduction and fertility. Supplement,
I L Cameron, and
K R Cook, and
D Edwards, and
G D Fullerton, and
G Schatten, and
H Schatten, and
A M Zimmerman, and
S Zimmerman
January 1975,
Development, growth & differentiation,
