English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In recent reports from this laboratory, it has been shown that a series of complex events occur at the gamete surfaces after spermatozoa contact the egg (Hart- mann, Gwatkin & Hutchison, 1972; Hartmann & Hutchison, 1973, 1974a, b). The relatively long period between the B1 and B2 bindings between the gamete surfaces suggests that changes occur which are a prelude to the penetration of the zona pellucida. Our earlier studies suggested that after pre-exposure to a population of eggs the spermatozoa were altered by the action of a vitelline factor in a manner which enabled them to bind sooner to a second population of eggs (Hartmann et al., 1972; Hartmann & Hutchison, 1974a). In this report, it will be shown that following B1 the zona pellucida is also altered in a manner which apparently prepares it for the final binding step (B2). Spermatozoa were collected from the caudal portion of the epididymis of the golden hamster (Mesocricetus auratus) and capacitated by the method outlined by Gwatkin & Williams (1970) with the exception that the Medium 199 (Morgan, Morton & Parker, 1950) was modified to contain sodium pyruvate (30 /tg/ml), crystalline bovine serum albumin (3 mg/ml) and sodium bicarbonate (2 mg/ml). This medium was designated 199M2 (R. B. L. Gwatkin, personal communication). The binding of the spermatozoa to the eggs was scored as previously described (Hartmann & Gwatkin, 1971). To detect changes on the surface of the zona pellucida before B2, the eggs were exposed successively to two drops of medium containing capacitated spermatozoa. After 25 min in the first drop, a time period representing the later part of the B1-B2 interval, the spermatozoa were detached by transfer with a micropipette through three washes of 199M2. Most spermatozoa were removed after the first wash. The washed eggs were then exposed to the second drop containing spermatozoa and binding was scored at various intervals thereafter. The results (Text-fig. 1) show that the spermatozoa in the second drop went through an apparently normal Bl, with a peak at 3 min, but that B2 and pene¬ tration occurred earlier than in control eggs. This change in the zona pellucida was referred to as 'priming', and was assayed by scoring for early B2 at 30 min. To determine whether the soluble portion of the spermatozoa could prime, we exposed eggs to the supernatant of the spermatozoa for 25 min, washed the eggs and then challenged them with capacitated spermatozoa. The results are shown in Table 1. The supernatant failed to prime the eggs or exhibited only

MAMMALIAN FERTILIZATION IN VITRO: SPERMINDUCED PREPARATION OF THE ZONA PELLUCIDA OF GOLDEN HAMSTER OVA FOR FINAL BINDING