The Manner of Sperm Entry in the Starfish Egg

Chambers, Robert

doi:10.2307/1537113

Cited by 30 publications

(16 citation statements)

References 5 publications

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“…1) . Reacted sperm can be identified easily, as the flagella now project laterally from the midpiece, an observation initially made by Chambers (1930) and confirmed by Dan (1954) and Colwin (1955, 1956) . The anterior surface of the head no longer appears flattened, but is rounded .…”

Section: Morphology Light Microscopymentioning

confidence: 73%

The Polymerization of Actin: Its Role in the Generation of the Acrosomal Process of Certain Echinoderm Sperm

Tilney

Hatano

Ishikawa

et al. 1973

The Journal of Cell Biology

315

125

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When Asterias or Thyone sperm come in contact with egg jelly, a long process which in Thyone measures up to 90 µm in length is formed from the acrosomal region . This process can be generated in less than 30 s . Within this process is a bundle of microfilaments . Water extracts prepared from acetone powders of Asterias sperm contain a protein which binds rabbit skeletal muscle myosin forming a complex whose viscosity is reduced by ATP . Within this extract is a protein with the same molecular weight as muscle actin . It can be purified either by collecting the pellet produced after the addition of Mg++ or by reextracting an acetone powder of actomyosin prepared by the addition of highly purified muscle myosin to the extract . The sperm actin can be polymerized and by electron microscopy the polymer is indistinguishable from muscle F-actin . The sperm actin was shown to be localized in the microfilaments in the acrosomal processes by : (a) heavy meromyosin binding in situ, (b) sodium dodecyl sulfate (SDS) gel electrophoresis of the isolated acrosomal processes and a comparison to gels of flagella which contain no band corresponding to the molecular weight of actin, and (c) SDS gel electrophoresis of the extract from isolated acrosomal caps . Since the precursor for the microfilaments in the unreacted sperm appears amorphous, we suspected that the force for the generation of the acrosomal process is brought about by the polymerization of the sperm actin . This supposition was confirmed, for when unreacted sperm were lysed with the detergent Triton X-100 and the state of the actin in the sperm extract was analyzed by centrifugation, we determined that at least 80% of the actin in the unreacted sperm was in the monomeric state .

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Section: Morphology Light Microscopymentioning

confidence: 73%

The Polymerization of Actin: Its Role in the Generation of the Acrosomal Process of Certain Echinoderm Sperm

Tilney

Hatano

Ishikawa

et al. 1973

The Journal of Cell Biology

315

125

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“…While these changes in the structure of the sperm aster are taking place, the heartshaped male pronucleus transforms into a spheroid (Figs. [19][20][21].…”

Section: Formation Of the Sperm Astermentioning

confidence: 99%

THE FINE STRUCTURE OF PRONUCLEAR DEVELOPMENT AND FUSION IN THE SEA URCHIN, ARBACIA PUNCTULATA

Longo

Anderson

1968

The Journal of Cell Biology

236

137

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Fertilization events following coalescence of the gamete plasma membranes and culminating in the formation of the zygote nucleus were investigated by light and electron microscopy in the sea urchin, Arbacia punctulata. Shortly after the spermatozoon passes through the fertilization cone, it rotates approximately 180 ° and comes to rest lateral to its point of entrance. Concomitantly, the nonperforated nuclear envelope of the sperm nucleus undergoes degeneration followed by dispersal of the sperm chromatin and development of the pronuclear envelope. During this reorganization of the sperm nucleus, the sperm aster is formed. The latter is composed of ooplasmic lamellar structures and fasciles of microtubules. The male pronucleus, sperm mitochondrion, and flagellum accompany the sperm aster during its migration. As the pronuclei encounter one another, the surface of the female pronucleus proximal to the advancing male pronucleus becomes highly convoluted. Subsequently, the formation of the zygote nucleus commences with the fusion of the outer and the inner membranes of the pronuclear envelopes, thereby producing a small internuclear bridge and one continuous, perforated zygote nuclear envelope.

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“…Prior to sperm movement in other animal eggs, the sperm nuclear material decondenses and forms a small pronucleus before transport. In many eggs, the formation of a sperm aster is observed at the site of the male pronucleus prior to movement to the deeper central cytoplasm (Chambers, 1933). In contrast, such a "sperm aster" was not observed with the rapid translocation events in D. polymorpha sperm; however, aster formation may be very small and could have been overlooked.…”

Section: Discussionmentioning

confidence: 99%

Analysis of fertilization and polyspermy in serotonin-spawned eggs of the zebra mussel,Dreissena polymorpha

Misamore¹,

Silverman

Lynn

1996

Mol. Reprod. Dev.

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Eggs isolated from animals spawned with 10−3 M serotonin were inseminated with sperm concentrations ranging from 103–106 sperm/ml. Multiple sperm attached to the surface of the egg and sperm incorporation occurred within 3 min postinsemination (PI). Sperm mitochondria, centrioles, and flagellum were also incorporated. Incorporation was essentially complete by 6 min PI. In the egg cortex, the sperm head rotated 180°, and a rapid translocation of the sperm through the cytoplasm towards the egg interior began by 5–6 min PI. In heavily polyspermic inseminations, translocations of the sperm were either minimal or nonexistent. In monospermic eggs, nuclear decondensation occurred after translocation was complete, beginning by 9–10 min PI. A male pronucleus began to develop in the cytoplasm by 21 min PI and enlarged to 20 μm before fusing with the female pronucleus. Oscillation of the egg cytoplasm and mitotic spindle apparatus was observed immediately prior to cleavage. Cleavage occurred at 60 min PI. Sperm incorporation and pronuclear formation were confirmed with fluorescent and confocal microscopy using the DNA‐specific dyes Hoescht 33342 and 7‐aminoactinomycin D. In sperm concentrations >104 sperm/ml, 26–76% of the eggs exhibited polyspermy. The high incidence of polyspermy suggests that rapid, effective blocks to polyspermy were not present or were ineffective in a significant proportion of serotonin‐spawned eggs. © 1996 Wiley‐Liss, Inc.

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The Manner of Sperm Entry in the Starfish Egg

Abstract: In an article published several years ago (Chambers, 1923) I de-

Cited by 30 publications

References 5 publications

The Polymerization of Actin: Its Role in the Generation of the Acrosomal Process of Certain Echinoderm Sperm

The Polymerization of Actin: Its Role in the Generation of the Acrosomal Process of Certain Echinoderm Sperm

THE FINE STRUCTURE OF PRONUCLEAR DEVELOPMENT AND FUSION IN THE SEA URCHIN, ARBACIA PUNCTULATA

Analysis of fertilization and polyspermy in serotonin-spawned eggs of the zebra mussel,Dreissena polymorpha

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