Effects of proteolytic enzymes on the zona pellucida of fertilized and unfertilized mammalian eggs

Chang, M. C.; Hunt, Dorothy M.

doi:10.1016/0014-4827(56)90128-8

Cited by 68 publications

(17 citation statements)

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“…After fertilization, the rabbit zona pellucida becomes significantly more resistant to digestion by trypsin (Chang & Hunt, 1956;Conrad, Buckley & Stambaugh, 1971), and to acrosin (present results), and yet the zonas of previously fertilized and un¬ fertilized rabbit eggs placed together in the same oviduct are penetrated by the same number of spermatozoa in 3-4 h (Overstreet & Bedford, 1974). The results obtained here with WGA treatment are similar in principle, because the effects of WGA persist during oviductal incubation.…”

Section: Discussionsupporting

confidence: 87%

Normal penetration of rabbit spermatozoa through a trypsin- and acrosin-resistant zona pellucida

Bedford¹,

Cross²

1978

Reproduction

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Exposure of rabbit ova to wheat germ agglutinin (WGA) at a concentration of 50 microgram/ml for 30-45 min rendered the zona pellucida at least 10 times more resistant to digestion by 1 mg trypsin/ml, and also more resistant to acrosin. Nevertheless, the zonas of WGA-treated eggs were penetrated by spermatozoa as readily as those of untreated eggs in the same oviduct. These results suggest that penetration of spermatozoa through the zona pellucida may not require the agency of a trypsin-like enzyme acting as a primary zona lysin. The validity of the general belief that a lysin in necessary for zona penetration is considered briefly in relation to the mode of penetration and structural organization of the mammalian sperm head.

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Section: Discussionsupporting

confidence: 87%

Normal penetration of rabbit spermatozoa through a trypsin- and acrosin-resistant zona pellucida

Bedford¹,

Cross²

1978

Reproduction

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“…All rabbits in this series were primed. These results confirm statistically the previous observations of Chang & Hunt (1956), Smithberg (1953) and Gwatkin (1964), which indicated that the zona pellucida of the fertilized ovum is more resistant to proteolysis than the zona of the unfertilized ovum. However, an excessive amount of proteolytic enzyme (15-0 mU trypsin/ml) will overcome this inhibition and the difference will no longer be evident.…”

supporting

confidence: 95%

Studies on the Nature of the Block to Polyspermy in Rabbit Ova

Conrad¹,

Buckley²,

Stambaugh³

1971

Reproduction

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“…Our capillary suction experiments did detect a 56% reduction in zona deformability in early two-cell hamster embryos compared with pre-fertilization oocytes. This is the first mechanical confirmation of the zona hardening that follows fertilization in this species, in which no hardening phenomenon is detectable by other methods [Chang and Hunt, 1956; Inoue and Wolf, 19751. In the mouse, where zona hardening is easily detected by solubility methods [reviewed by Wolf, 19811, we were also able to demonstrate a significant reduction in deformability.…”

mentioning

confidence: 54%

Factors regulating mammalian sperm migration through the female reproductive tract and oocyte vestments

1989

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Mechanisms of mammalian sperm migration through the female reproductive tract and ovum vestments are described. The perspective is biophysical as well as biochemical and morphological, and the focus is upon the role of sperm motility in these processes. Sperm forward progression is characterized as an interactive process between the the cell and its environment, and the mediation of flagellar bend propagation by the physical properties of its surroundings is described. These properties, together with flagellar beat kinematics, sperm morphology, and surface properties, determine the magnitude of the forces generated by sperm and their consequent rate of progression. Sperm interactions with the cervical mucus, the cumulus oophorus, and the zona pellucida are described. The poorly understood affinity of the sperm surface for the macromolecules of the mucus, cumulus, and zona is stressed, as is the viscoelastic structural mechanical resistance of these biopolymers to sperm motion. The kinematics and consequences of hyperactivated sperm motion are presented, with emphasis on objective characterization of such motion (as a biomarker), along with analysis of the mechanical advantage that such motion may confer on spermatozoa during egg-vestment interaction. Key words: sperm, transport, mucus, cumulus, zona pellucida, fertilization INTRODUCTIONFlagellar movement is a fundamental expression of the vitality of a sperm cell, and is essential for its reproductive function. The active mechanism of flagellar motion produces a sequence of principal and reverse bends [Gibbons and Gibbons, 1974; Woolley, 19771. These can have varying degrees of curvature and can be initiated and propagated along the flagellum at different rates. Flagellar bending results in a distribution of local forces and torques against the surrounding fluid. In accordance with Newton's Third Law, these are resisted by equal and opposite local forces and torques. In order to satisfy Newton's Second Law, the summation of the local local external forces and torques over the sperm head and tail must be zero. As a consequence, there Received November 8, 1988; accepted November 17, 1988. Address reprint requests to David F. Katz In a general biophysical sense, mammalian sperm swim optimally; the principles of hydrodynamics and optimal control theory demonstrate that the smooth flagellar traveling waves, commonly seen in low-viscosity media, tend to maximize the sperm's propulsive velocity with respect to the hydrodynamic power output (Pironneau and Katz, 1974). Mammalian sperm must use their swimming ability to reach the oocyte-cumulus complex, and the forces due to flagellar motion assist them in penetrating the egg vestments to reach the oolemma.Our studies of these processes are hampered by their complexity and by apparent variation among species. Some of this biological variation is real; for example, the site of semen deposition may be the vagina, cervix, or uterus. These environments differ not only with respect to their distance from the site of ferti...

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Effects of proteolytic enzymes on the zona pellucida of fertilized and unfertilized mammalian eggs

Cited by 68 publications

References 1 publication

Normal penetration of rabbit spermatozoa through a trypsin- and acrosin-resistant zona pellucida

Normal penetration of rabbit spermatozoa through a trypsin- and acrosin-resistant zona pellucida

Studies on the Nature of the Block to Polyspermy in Rabbit Ova

Factors regulating mammalian sperm migration through the female reproductive tract and oocyte vestments

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