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PubMed1985

Abnormal chromosome behavior in human oocytes which remained unfertilized during human in vitro fertilization.

Chromosomal abnormalities and abnormal embryonic development have previously been observed after human in vitro fertilization (IVF). Chromosomal abnormalities may arise not only after fertilization but even earlier during meiotic maturation of human oocytes in culture. Since chromosomal analysis is simple in oocytes during meiotic maturation, the chromosomal status was analyzed in oocytes which remained unfertilized in a human in vitro fertilization program. In 50 fertilization attempts the chromosomes of 62 unfertilized oocytes could be analyzed; 45 of them were in the process of meiotic maturation. In three oocytes two small polar bodies were observed 16-18 hr after insemination in the absence of fertilization. In one oocyte abnormal chromosome behavior was found during the first meiotic division, and in four oocytes during metaphase of the second meiotic division. These data suggest that chromosomal analysis of unfertilized oocytes in human IVF may improve the understanding human oocyte maturation and fertilization.

Chromosome Aberrations↗
PubMed1992

Enhancing in vitro fertilization of mouse oocytes by partial zona pellucida digestion.

This work was undertaken in order to evaluate the effect of partial zona digestion on fertilization in vitro of mouse oocytes and assess zona surface changes induced by the procedure. Three hundred forty-six oocytes allocated for treatment were exposed to Ham's F-10 medium supplemented with 0.5% Pronase for either 3 min (188 oocytes) or 5 min (158 oocytes); 324 oocytes served as controls. Oocyte losses incurred as a result of the procedure were small (15 oocytes; 4.3%). Control and Pronase-treated oocytes were each divided into four subgroups and inseminated with 5 x 10(5), 5 x 10(4), 5 x 10(3), or 5 x 10(2) sperm cells/ml. Fertilization was assessed 8 hr following insemination by the appearance of two pronuclei and development to the two- to four-cell stage the following day. The morphology of the zona pellucida following Pronase treatment was assessed by phase-contrast and scanning electron (SEM) microscopies performed immediately after treatment. Fertilization rate of control oocytes was 80% at a sperm concentration of 500,000/ml and gradually declined to approximately 30% at 500 cells/ml. In contrast, treated oocytes inseminated with 500 sperm cells/ml demonstrated a normal rate of fertilization. At this low sperm concentration the longer Pronase treatment was significantly (P less than 0.05) more efficient in enhancing fertilization (69 and 88% for 3 and 5 min of Pronase treatment, respectively). Polyspermic fertilization was not observed in any of the subgroups. Phase-contrast microscopic examination of oocytes at the time of Pronase treatment showed an initial swelling of the zona pellucida for 30-60 sec with a time-dependent increase in its transparency.

Animals↗
PubMed1992

The effect of caffeine on the ability of spermatozoa to fertilize mature human oocytes.

Although caffeine has been reported to enhance spermatozoon motility as well as fertilizing ability, its use in clinical practice has remained sparse. We report here the results carried out to assess the effect of exposing normal human spermatozoa to different concentrations of caffeine on their motility, their ability to fertilize oocytes, and the subsequent development of resulting embryos. Mature human oocytes were inseminated with spermatozoa washed and capacitated in 1.25, 2.5, and 5 mM caffeine. The fertilization rates were compared with control oocytes inseminated with untreated spermatozoa. While caffeine was observed to improve significantly various motility parameters in a dose-dependent manner, it did not lead to an improvement in the fertilization rates. At the highest concentration, 5 mM, it adversely affected the fertilization rate: 38%, compared with 78% in controls. Embryonic development was also observed to be retarded at the lower concentrations, while it was virtually inhibited in the 5 mM concentration group. Our results suggest that while a definite improvement in motility may occur when spermatozoa are exposed to caffeine, this improvement did not translate into enhanced fertilizing ability and subsequent embryonic development. We are therefore of the opinion that the use of caffeine as a spermatozoon motility enhancer requires further studies prior to wider clinical use in assisted pregnancy programs.

Caffeine↗
PubMed1991

Marriage rate and fertility in cycloid psychosis: comparison with affective disorder, schizophrenia and the general population.

A cohort of patients with cycloid psychosis (n = 34) admitted to hospital for the first time in 1925 was compared with affective patients (n = 30) and schizophrenic patients (n = 81) admitted at the same time as well as with the general population in the catchment area. The marriage rate in cycloid probands was in accordance with that of the general population at index admission. Five years later it was significantly lower than expected, but after 10 years the marriage rate was statistically in accordance with expected figures. Fertility was significantly higher than in schizophrenic probands (P less than 0.001). Fertility in cycloid women was in accordance with expected figures based on the mean fertility of birth cohorts of women. It was, however, significantly lower than expected, both in affective women (P less than 0.05) and in schizophrenic women (P less than 0.0001). Prepsychotic fertility (before the index episode) did not significantly diverge from expected figures in cycloid women. It was, however, significantly lower both in affectively ill (P less than 0.05) and schizophrenic women (P less than 0.001). Postpsychotic fertility in cycloid women was in accordance with expected figures. In affective women it also approximated normality, but in schizophrenic women it was significantly lower than expected. Marital fertility was within the expected interval in cycloid probands. The observations are in support of the opinion that neither prepsychotic nor postpsychotic conditions constitute an unsurmountable obstacle to normal social adaptation in cycloid patients. The differences are also interpreted as an argument in favour of nosological autonomy of the category of cycloid psychosis.

Adult↗
PubMed1994

Sperm:oocyte ratios in an in vitro fertilization (IVF) program.

PURPOSE: During the past few years, many oocyte insemination techniques, including microinjection, have evolved in the treatment of male-factor infertility. This preliminary study was designed to evaluate whether microdroplet insemination could be considered a reliable technique, especially for semen samples with male-factor defects. The first objective was to assess fertilization rates obtained by inseminating sibling oocytes using both the conventional IVF and the microdroplet method (Group 1). The second objective was to evaluate subsequent embryo development and pregnancy rates resulting from microdroplet insemination, in addition to formulating adequate sperm:oocyte ratios for various semen categories (Group 2). Four semen categories were studied including fresh normal sperm, frozen/thawed normal sperm, and male-factor sperm with one defect and two or three defects. RESULTS: Group 1 consisted of 54 couples; no statistical significance was found in the fertilization rates between test tube and microdroplet insemination in all four semen categories. Based on these results, patients from Group 2 (48 couples) had their oocytes inseminated only in microdroplets with sperm:oocyte ratios ranging from 2000 to 10,000 motile sperm:1 oocyte. The average fertilization rate for male-factor sperm was 55%, with a 91% cleavage rate. CONCLUSION: Higher fertilization rates were observed in the lowest range of sperm:oocyte ratios (2000-4000:1) for male-factor sperm with one defect and in the highest range (8000-10,000:1) for male-factor sperm with two or three defects. Polyspermy occurred in only 0.4% of the oocytes inseminated. Microdroplet insemination is an alternative treatment for moderate to moderately severe male-factor infertility, establishing a bridge between conventional IVF and microinjection. With adequate sperm:oocyte ratios, this technique allows the natural selection process of fertilization in vitro to take place, without the high incidence of polyspermy or mechanical damage frequently observed in assisted fertilization techniques.

Adult↗
PubMed1994

Successful freezing of unfertilized mouse oocytes and effect of cocultures in oviducts on development of in vitro fertilized embryos after thawing.

PURPOSE: To establish a freeze-thawing method for unfertilized oocytes with a high success rate, we examined several conditions for freeze-thawing. The effects of EDTA and cocultures in oviducts on the development of embryos fertilized in vitro after thawing were also studied. RESULTS: In the first experiment, unfertilized oocytes that were frozen in 1.5 M dimethylsulfoxide (DMSO) supplemented with 0.2 M sucrose by a slow freeze-thawing method showed the best results (fertilization rate, 71.9%; blastocyst rate per frozen oocyte, 18.8%). The proportion of embryos that developed to blastocysts was significantly higher when DMSO was added at 4 degrees C than at room temperature (39.4 vs 19.4%; P < 0.01). The addition of EDTA (10 microM) to the culture medium did not promote embryo development after fertilization in vitro. However, the rate of development of in vitro fertilized embryos to blastocysts after thawing was significantly higher when the embryos were cultured in oviducts in vitro than the rates in control cultures and those cultured with EDTA (blastocyst rate from fertilized oocytes, 71.4 vs 51.0 and 52.8%, respectively; P < 0.01). CONCLUSION: Unfertilized mouse oocytes can be cryopreserved successfully by a slow freeze-thawing method with the addition of 1.5 M DMSO and 0.2 M sucrose at low temperatures, and coculture with oviducts enhances the development of embryos that are fertilized in vitro after thawing.

Animals↗
PubMed2004

Involvement of nitric oxide during in vitro fertilization and early embryonic development in mice.

Nitric oxide (NO) has emerged as an important intracellular and intercellular messenger, controlling many physiological processes and participating in the fertilization process via the autocrine and paracrine mechanisms. This study investigated whether nitric oxide synthase (NOS) inhibitior (L-NAME) and L-arginine could regulate in vitro fertilization and early embryonic development in mice. Mouse epididymal spermatozoa, oocytes, and embryos were incubated in mediums of variable conditions with and without L-NAME or L-arginine (0.5, 1, 5 and 10 mM). Fertilization rate and early embryonic development were significantly inhibited by treating sperms or oocytes with L-NAME (93. 8% vs 66.3%, 92.1% vs 60.3%), but not with L-arginine. In contrast, fertilization rate and early embryonic development were conspicuously reduced when L-NAME or L-arginine was added to the culture media for embryos. Early embryonic development was inhibited by microinjection of L-NAME into the fertilized embryos in a dose-dependent manner, but only by high concentrations of L-arginine. These results suggest that a moderate amount of NO production is essential for fertilization and early embryo development in mice.

Animals↗
PubMed1989

Oocyte fertilization in vitro is associated with high follicular immunoreactive beta-endorphin levels.

Follicular fluid (FF) levels of immuno reactive beta-Endorphin (i.r. beta-EP), i.r. gamma-Endorphin (i.r. gamma-EP), i.r. alpha-melanocyte-stimulating hormone (i.r. alpha-MSH), androgens and estrogens were measured in 76 preovulatory follicles obtained, after gonadotropin stimulation from 19 women undergoing in vitro fertilization (IVF). The aim of the study was to investigate the relationships existing between peptide contents of FF and both oocyte-cumulus-corona-complex (OCCC) maturity and the success of IVF. Peptides and steroids were measured by RIA after FF extraction with liquid chromatography and ethyl-ether, respectively. Out of the total of 76 oocytes, 52 were fertilized in vitro and 35 of them underwent normal cleavage and were transferred. Among the three peptides, only i.r. beta-EP levels were higher in FF from follicles which contained oocytes that were subsequently fertilized (127.6 +/- 16.2 pmol/L mean +/- SE) than in FF from follicles which contained oocytes that did not subsequently fertilized (62.9 +/- 8.4, p less than 0.04). Independent of subsequent fertilization, i.r. alpha-MSH values in FF were 5 times higher than those of i.r. beta-EP and i.r. gamma-EP. In the presence of a morphologically mature oocyte, FF i.r. gamma-EP levels (165.2 +/- 45.3 pmol/L) were higher than in FF from follicles yielding immature (63.6 +/- 13.5, p less than 0.01) or luteinized (32.7 +/- 9.2, p less than 0.01) oocytes. Steroid levels in FF did not change in relation to oocyte maturity or subsequent oocyte fertilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed2005

Chromosomal location of a pollen fertility-restoring gene, Rf, for CMS in Japanese bunching onion (Allium fistulosum L.) possessing the cytoplasm of A. galanthum Kar. et Kir. revealed by genomic in situ hybridization.

In a previous study, we developed cytoplasmic male sterile lines of Allium fistulosum possessing the cytoplasm of A. galanthum, a wild species, by continuous backcrossing. Furthermore, we reported the presence of a pollen fertility-restoring gene (Rf) for cytoplasmic male sterility (CMS) in A. fistulosum from segregation of pollen fertility of backcross progenies. In the present study, genomic in situ hybridization (GISH), using genomic DNA of A. galanthum as the probe DNA and that of A. fistulosum as the blocking DNA, was applied to F(1) hybrids between both species and backcross progenies to determine the chromosomal location of the Rf locus. By means of GISH, eight chromosomes from A. galanthum were clearly discriminated from those of A. fistulosum in the F(1) hybrids, and chromosome substitution process through continuous backcrossing was visualized. Interestingly, the chromosome region from A. galanthum, specific to male fertile plants, was detected in one chromosome of BC(4) to BC(7) generations. Based on the karyotype analysis of the male fertile plants, the chromosome was identified as the 5F chromosome. Our results confirm that the Rf locus is located on the 5F chromosome of the male fertile plants. This is the first report that identified the chromosomal location of the pollen fertility-restoring gene in A. fistulosum.

Allium↗
PubMed2006

Identification of AFLP markers linked to the male fertility restorer gene of CMS (Moricandia arvensis) Brassica juncea and conversion to SCAR marker.

We have developed a cytoplasmic male sterile (CMS) line of Brassica juncea through somatic hybridization with Moricandia arvensis and introgressed the fertility restorer gene into B. juncea. This fertility restorer locus is unique in that it is capable of restoring male fertility to two other alloplasmic CMS systems of B. juncea. As a first step toward cloning of this restorer gene we attempted molecular tagging of the Rf locus using the amplified fragment length polymorphism (AFLP) technique. A BC(1)F(1) population segregating for male sterility/fertility was used for tagging using the bulk segregant analysis method. Out of 64 primer combinations tested in the bulks, 5 combinations gave polymorphic amplification patterns. Further testing of these primers in individual plants showed four amplicons associated with the male fertility trait. Polymorphic amplicons were cloned and used for designing SCAR primers. One of the SCAR primers generated amplicons mostly in the fertile plants. Linkage analysis using MAPMAKER showed two AFLP and one SCAR markers linked to the male fertility gene with a map distance ranging from 0.6 to 2.9 cM. All the markers are located on one side of the Rf locus.

Fertility↗
PubMed2006

Nitrogen fertilizer and gender effects on the secondary metabolism of yaupon, a caffeine-containing North American holly.

Yaupon (Ilex vomitoria) is a caffeine-containing dioecious shrub native to the southeastern United States that was historically brewed into a stimulating beverage. We tested predictions of the carbon/nutrient balance (CNB) hypothesis by determining whether nitrogen availability and gender influence production of caffeine and related alkaloids as well as phenolic compounds in leaves of pot-grown yaupon plants fertilized with ammonium nitrate. The CNB hypothesis predicts that additional nitrogen should result in increased alkaloid concentrations and decreased phenolic concentrations. An extension of the CNB hypothesis to dioecious plants predicts that females have higher C/N ratios and therefore higher phenolic concentrations and lower alkaloid concentrations than male conspecifics. In our study, caffeine and total alkaloid concentrations were 5-10 times higher in fertilized than control plants but did not vary by gender. Nevertheless, an observed interaction between gender and fertilization suggests that females respond more to fertilization than males in caffeine production. In addition, fertilized plants not only contained higher concentrations of alkaloids and total nitrogen but also allocated a larger proportion of their nitrogen to alkaloid production than control plants. Total phenolic concentrations were higher in control females than control males as predicted by the CNB hypothesis, but did not vary by treatment nor were there differences by gender among fertilized plants. We also found high correlations between antioxidant capacity and both classes of phenolic compounds detected in our study (cinnamic acid derivatives and flavonoids) indicating that in addition to their putative defensive function against herbivores, phenolics protect yaupon from oxidative stress. Explanation of the inconsistencies between our data and predictions of the CNB hypothesis may benefit from a re-appraisal of the physiological mechanisms by which resource availability affects secondary metabolism as well as consideration of the selective pressures to which secondary metabolism responds.

Alkaloids↗
PubMed2006

The potential impact of antiretroviral therapy on fertility in sub-Saharan Africa.

Approximately 14 million women of child-bearing age are living with HIV/AIDS in sub-Saharan Africa. Women with HIV infection have between 25% and 40% lower fertility than noninfected women. As antiretroviral (ARV) therapy becomes increasingly accessible in sub-Saharan Africa, it is important to understand whether and how the associated clinical improvements correspond with changes in the incidence of pregnancy and fertility. Accordingly, this paper reviews the literature on the potential impact of ARV therapy on the fertility of women with HIV infection in sub-Saharan Africa. We use Bongaarts' proximate determinants of fertility framework (adapted for conditions of a generalized HIV epidemic) to examine the underlying mechanisms through which use of ARV therapy may impact the fertility of women with HIV infection. A conceptual framework is proposed to guide future research aimed at understanding how widespread use of ARV therapy may impact fertility in sub-Saharan Africa.

Africa South of the Sahara↗
PubMed1991

Recurrent failure of in vitro fertilization: role of the hemizona assay in the sequential diagnosis of specific sperm-oocyte defects.

The results of predictive fertilization bioassays (hemizona assay, hamster ova-human sperm penetration assay), in vitro fertilization treatment, fertile donor cross-match tests with either sperm or oocytes, and oocyte micromanipulation for assisted fertilization were used to establish a pathophysiologic diagnosis in cases of recurrent failed fertilization in vitro. Disorders of sperm function manifested at the level of zona binding, zona penetration, oolemma fusion, and pronuclear decondensation as well as oocyte anomalies were considered to represent the specific gamete defects that led to abnormal sperm-oocyte interactions (i.e., failed fertilization). Our findings show that the sequential application of bioassays can elucidate specific sperm or oocyte defects that characterize functional abnormalities among sperm populations.

Acrosome↗
PubMed1994

Unsuspected Chlamydia trachomatis infection and in vitro fertilization outcome.

OBJECTIVE: Chlamydia trachomatis infections of the female genital tract, although a major cause of infertility, are often asymptomatic and undetected. Since many infertile women now seek in vitro fertilization, a procedure whereby fertilization and embryo implantation are precisely timed, we sought to determine the relation between an unsuspected C. trachomatis infection and the ability of embryos to implant and develop after their transfer to the uterus. STUDY DESIGN: At the time of oocyte aspiration, endocervical samples were obtained from 216 women and assayed by enzyme-linked immunoassay for immunoglobulin A antibodies to C. trachomatis structural membrane components and to recombinant C. trachomatis heat shock protein. The presence of C. trachomatis in the cervices was assessed by the polymerase chain reaction. The outcome of each in vitro fertilization cycle was then ascertained. RESULTS: Oocytes from 198 (91.7%) of the women were fertilized in vitro and subsequently transferred to the uterus. Term deliveries of healthy infants occurred after 68 (34.3%) of these transfers. Cervical immunoglobulin A antibodies to chlamydial heat shock protein were detected in 5 (7.3%) of the women with term births, and 1 (1.5%) also had immunoglobulin A antibody to chlamydial structural components; 3 (4.4%) were positive by the polymerase chain reaction for C. trachomatis. In contrast, among the 130 women whose embryo transfers did not result in an ongoing pregnancy, 36 (27.7%) had cervical antiheat shock protein immunoglobulin A (p = 0.0007) and 24 (18.5%) had antichlamydial structural component immunoglobulin A (p = 0.0002); 15 (11.5%) of these women had positive results of polymerase chain reaction for C. trachomatis. The majority of women with cervical antibodies to chlamydial structural antigens were also positive for antibody to heat shock protein. However, only 35% of the women with antibodies to heat shock protein were also positive for the other chlamydial antibodies. C. trachomatis was detected by polymerase chain reaction in 29.2% of women with anti-C. trachomatis antibodies and 7.8% of women with anti-heat shock protein antibodies. Women positive for antichlamydial immunoglobulin A were more likely to be undergoing a repeat in vitro fertilization cycle than were women who were antibody negative (p = 0.007). CONCLUSION: Unsuspected C. trachomatis infection or reactivation of an immune response to the C. trachomatis heat shock protein may induce an inflammatory reaction in the uterus that impairs embryo implantation and/or facilitates immune rejection after uterine transfer of in vitro fertilized embryos.

Antibodies, Bacterial↗
PubMed1986

Changes in triacylglycerol, diacylglycerol and free fatty acids after fertilization in developing toad embryos.

The content and fatty-acid composition of triacylglycerols, diacylglycerols and free fatty acids were analyzed from the unfertilized oocyte stage to the gastrula stage in the toad Bufo arenarum Hensel. Fertilization triggered a 30% and a 40% decrease in triacylglycerol and diacylglycerol, respectively. In contrast, free fatty acid increased continuously from oocyte to gastrula stage with an accumulation of palmitate predominating. However, the observed increase in free fatty acid was too small to account for the decreases in both neutral glycerides. The decrease in triacylglycerol might be a reflection of the activation of lipolytic enzymes and the subsequent oxidation of fatty acids to meet the increased metabolic energy requirements brought on by fertilization. The diminished diacylglycerol content due to fertilization may be accounted for, at least in part, by the utilization of diacylglycerol in the synthesis of membrane phospholipids, inasmuch as their decrease occurred simultaneously with an increase in phosphatidic acid. When cell-free homogenates taken from the three stages of development (unfertilized, fertilized and gastrula) were incubated in Tris-Ringer buffer for 90 min, free fatty acid accumulated. Triacylglycerol and diacylglycerol did not change substantially during this incubation period. This fact indicates that the free fatty acid released during incubation was not derived from neutral glycerides, but probably from membrane phospholipids. The release of free fatty acid was significantly greater in samples from the fertilized oocyte stage. The results described in this paper suggest that the synthesis of membrane phospholipids, including an enhanced turnover of the acyl moiety, plays a significant role in the metabolic events activated by fertilization.

Animals↗
PubMed1983

Timing the early events during sea urchin fertilization.

To determine precisely the timing, duration, and sequences of the earliest events during sea urchin (Lytechinus variegatus) fertilization, the bioelectric recordings of microelectrode-impaled eggs were electronically superimposed, by video mixing, over the microscopic differential interference contrast image of the same egg at insemination. Videotape analysis, utilizing a slow-motion analyzer, demonstrates that the successful sperm triggers the bioelectric membrane potential reversal within 3.36 +/- 3.02 sec (0.72-9.76 sec range; sigma = 23 eggs) of sperm-egg attachment. This sperm, actively gyrating about its attachment site, is indistinguishable from the other, unsuccessful sperm until 12.66 +/- 2.72 sec (6.72-16.60 sec range; sigma = 15) later when the sperm tail ceases its beating and sperm incorporation ensues. The cortical granules begin to discharge, and the fertilization coat starts to elevate at the fusion site at 20.79 +/- 3.18 sec (13.62-26.08 sec range; sigma = 12) after the onset of the fertilization potential, i.e., an average of about 8 sec after the cessation of sperm-tail motility during incorporation. In most cases, the bioelectric responses starts within 7 sec of sperm adhesions; if the data are analyzed excluding the few slow cases, the fertilization potential is found to start 1.93 sec (+/- 1.28 sec) after sperm attachment. These results indicate that the first successful sperm triggers the fast block to polyspermy within 3.4 sec, perhaps as quickly as 1.9 sec, of sperm-egg adhesion, about 13 sec before the first morphological indication of fertilization, and about 21 sec before the characteristic elevation of the fertilization coat responsible for the late block to polyspermy.

Animals↗
PubMed1983

Fertilization of amphibian eggs: a comparison of electrical responses between anurans and urodeles.

In Pleurodeles waltl and Ambystoma mexicanum, which exhibit physiological polyspermy, the membrane potential in most eggs did not change in any consistent pattern during 45 min after fertilization; in some cases, a slow hyperpolarization began 5 to 15 min after insemination and continued for 10-15 min. These eggs then slowly depolarized, reaching a stable value of -10 to +10 mV, about 45 min after fertilization. Membranes of eggs activated by A23187 or by electrical stimulus showed a similar behavior. The diversity of responses does not correlate with the number of sperm fusing with the egg. Holding the membrane potential at a constant value between -40 and +40 mV during insemination did not prevent fertilization nor delay sperm-egg interactions. The fertilization or activation potential of Rana temporaria eggs consists of a rapid (1 sec) depolarization accompanied by a sudden decrease in membrane resistance. The activation potential can be triggered by A23187 and by calcium iontophoresis; its amplitude depends on the (Cl-)0 and to a lesser extent on the (Na+)0. Fertilization was prevented when the membrane potential was clamped above +15 mV. However, slowing the rise time (5 to 8 sec instead of 1 sec) and reducing the amplitude (10-20 mV instead of 40-60 mV) of the fertilization potential, both by injecting negative current, never induced polyspermy.

Amphibians↗
PubMed1986

The vitelline envelope to fertilization envelope conversion in eggs of Xenopus laevis.

Fertilization of the Xenopus laevis egg causes the conversion of the vitelline envelope to the fertilization envelope, a change reflected in the loss of sperm penetrability of the egg and the appearance of an electron-dense layer on the outer aspect of the fertilization envelope. As seen by one-dimensional gel electrophoresis, two components with molecular weights of 69,000 and 64,000 in the vitelline envelope were converted to 66,000 and 61,000 in the fertilization envelope. By two-dimensional gel electrophoresis, the components in the 69,000 and 64,000 molecular weight regions of the vitelline envelope were seen to shift to more basic isoelectric points upon conversion to the fertilization envelope. Peptide mapping by limited proteolysis suggested that the 69,000 and 64,000 molecular weight components shared the same polypeptide chains but the smaller glycoprotein lacked a carbohydrate side chain found on the larger species. Similar sites on each glycoprotein were affected when the vitelline envelope was converted to the fertilization envelope. No N-terminal amino acids could be identified on the envelope components, indicating that these glycoproteins have blocked N-termini. Ionophore A23187-activation of jellied eggs (but not dejellied eggs) caused the molecular weight changes in the absence of sperm. Thus, factors from the jelly and the cortical granules but not from sperm apparently are involved in the processing of the 69,000 and 64,000 molecular weight components.

Amino Acid Sequence↗