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PubMed1999

OsMADS13, a novel rice MADS-box gene expressed during ovule development.

MADS-box genes have been shown to play a major role in defining plant architecture. Recently, several MADS-box genes have been reported that are highly expressed in the ovule. However, only for the Petunia genes FBP7 and FBP11 has a function in defining ovule identity been shown. We have isolated a rice MADS-box gene named OsMADS13. Expression analysis has shown that this gene is highly expressed in developing ovules. In order to facilitate a detailed characterization of rice ovule-expressed genes, a comprehensive morphological description of ovule development in rice has been performed. The predicted amino acid sequence of OsMADS13 shows significant homology with ZAG2, a maize MADS-box gene, which is also expressed mainly in the ovule. Mapping of the gene in the rice genome showed that it is located on chromosome 12, which is syntenic to two maize regions where ZAG2 and its paralogous gene ZMM1 have been mapped. Our results suggest that OsMADS13 is the ortholog of ZAG2 and ZMM1 and might play a role in rice ovule and seed development.

Amino Acid Sequence↗
PubMed2000

A DEFICIENS homologue is down-regulated during apomictic initiation in ovules of Hieracium.

Hieracium is a member of the Asteraceae family, and contains sexual species in addition to apomictic species that reproduce by apospory and produce seed without fertilization. A homologue of the floral organ-identity gene DEFICIENS (DEF) was isolated from an apomictic line of Hieracium piloselloides (Vill.) following differential display between mature ovules and those initiating autonomous embryogenesis. The gene termed HPDEF has 93% amino acid identity with GDEF2, a DEF homologue isolated from Gerbera hybrida (D. Yu et al., 1999, Plant J. 17: 51-62), another member of the Asteraceae. In-situ analysis showed that early in floral development HPDEF is expressed in stamen and petal primordia, indicating expected B-function activity, according to the ABC model of floral organ identity (J. L. Bowman et al., 1991, Development 112: 1-20; E. S. Coen and E. M. Meyerowitz, 1991, Nature 353: 31-37). However, HPDEF expression was also observed in ovule primordia and expression continued in developing ovules until anthesis, indicating that this gene may have a role in ovule development. Expression of HPDEF was not detected in megaspore mother cells, or in sexual or aposporous embryo sacs. In sexual Hieracium, HPDEF was uniformly expressed throughout the ovule integument until anthesis. In most ovules of the apomict, however, HPDEF expression was transiently down-regulated in a specific zone in the chalazal region where cells initiating aposporous embryo sac formation differentiate. Uniform low-level HPDEF expression was subsequently observed prior to anthesis in ovules from sexual and apomictic plants. HPDEF may be down-regulated as a consequence of apomictic initiation and/or its down-regulation may facilitate progression of apomictic events.

Amino Acid Sequence↗
PubMed1982

The relationship between ovulation rate and embryonic survival in gilts.

Norwegian Landrace gilts were inseminated on the second day of their second oestrus and slaughtered 28 to 34 days after insemination. The number of corpora lutea (ovulation rate) and normal embryos was counted and the embryonic survival rate was calculated for the 306 pregnant gilts. Mean (+/-S.D.) ovulation rate, number of normal embryos and embryonic survival rate were 14.17+/-2.48, 10.55+/-3.30 and 74.8%+/-20.7%, respectively. The significant (P<0.001) curvilinear regression of embryonic survival rate on ovulation rate gives a maximum embryonic survival rate at 13.2 ovulations. Increased ovulation rate gives increased number of normal embryos up to 18.1 ovulations. Ovulation rate should be considered when assessing factors affecting embryonic survival in pigs.

Journal Article↗
PubMed1986

Seasonality of ovulation and estrus, and the ram effect in poll dorset ewes.

The effects of month on the proportion of Poll Dorset ewes expressing estrus and ovulating and on their ovulation rate when continually exposed to vasectomised rams and the effects of isolating the ewes from rams in winter/early spring were examined during 15 months in New South Wales, Australia. The percentage of ewes ovulating and their ovulation rate varied from 23% and 1.10 in November to an average of 99% and 1.85 in April and June, and the proportion of ewes expressing estrus followed a similar trend. Some ewes (6.8%) ovulated throughout the 15 months, and the average breeding season was 294 (SE = 6.1) days. Isolating ewes from rams in late winter/early spring significantly decreased the proportion of ewes ovulating from September to November, increased the proportion in December, but did not significantly alter ovulation rate. The variability in reproductive measures during spring offers scope for selection; with the ram effect, improvements in spring joining results from Dorset ewes are possible.

Journal Article↗
PubMed1990

Time of ovulations in dairy goats induced to superovulate with porcine follicle stimulating hormone during and out of the breeding season.

Alpine dairy goats were induced to superovulate at the end of a progestagen treatment with porcine follicle stimulating hormone (pFSH) during the breeding season (n = 10 goats) and out of the breeding season (n = 10 goats). Occurrence of estrus and of the luteinizing hormone (LH) peak were checked every 4 h. Ovulations were determined every 6 h by ovarian laparoscopic examination. Among the parameters studied, the mean interval from sponge removal to the onset of estrus did not differ whatever the season of treatment, but the variability was higher for females treated out of the breeding season. Ovulations began during the laparoscopic control period for nine of ten goats during the breeding season vs seven of ten goats out of the breeding season. For these 16 females, on which the LH peak and beginning of ovulation were known, the season did not affect the intervals between the onset of estrus and the LH peak and between the LH peak and the beginning of ovulation. When ovulations are observed by laparoscopy every 6 h, for any given goat 54.9% of total ovulations (counted 7 d after estrus) occurs in less than 6 h, and 87.1% in less than 12 h. Although the interval between the LH peak and the ovulation is quite constant, the additive variabilities of the intervals between the sponge removal and the onset of estrus and between the onset of estrus and the LH peak precluded the determination of an optimal time for artificial insemination (AI) by timing sponge removal or onset of estrus.

Journal Article↗
PubMed1991

Determination of ovulation time in bitches based on teasing, vaginal cytology, and elisa for progesterone.

The estrous cycle of 16 mature mongrel female dogs was monitored to evaluate the accuracy of teasing, vaginal cytology and quantitative ELISA progesterone assay to determine ovulation. The dogs were presented to male, and blood samples and vaginal swabs were taken daily during proestrus and estrus. Selected serum samples collected during estrus were assayed for endogenous LH by radioimmunoassay (RIA). Plasma samples collected during proestrus and estrus were assayed for progesterone with a commercially available ELISA kit. Ovulation was considered to take place 48 h after the preovulatory LH peak. Vaginal cytology smears were stained with Wright's stain and evaluated for the percentage of superficial squamous cells. Day 1 of diestrus (Day 1) was defined as a drop of 20% or more in the total number of superficial cells. Two standard curves (linear and best fitted curves) commonly used with ELISA were compared together and with the RIA progesterone assay. Ovulation was estimated to occur when progesterone concentration was 4.9 +/- 1.0 ng/ml (mean +/- SD, n = 15), with a range of 3.4 to 6.6 ng/ml. Based on vaginal cytology, ovulation took place 6.9 +/- 1.6 d (n = 15) after 80% of the squamous cells were superficial and 6.8 +/- 1.4 d (n = 16) before Day 1. Ovulation took place 2.1 +/- 3.9 d (n=11) after the first day of standing estrus and 8.8 +/- 1.5 d (n = 10) before the last day of receptivity. The two standard curves were found parallel to each other and to the RIA progesterone assay. Based on the results of the present study, ELISA progesterone assay and determination of the first day of estrus by vaginal cytology are reliable methods for predicting ovulation, whereas the last day of receptivity as determined by teasing and Day 1 as determined by vaginal cytology are reliable methods to retrospectively estimate ovulation time.

Journal Article↗
PubMed1996

Recovery rate and quality of embryos from mares inseminated after ovulation.

The aim of this study was to evaluate the quality of embryos and their recovery rate from mares inseminated at different intervals after ovulation. Finnhorse and warmblood mares were inseminated with fresh semen 8 to 16 h, 16 to 24 h, or 24 to 32 h after ovulation. Control mares were inseminated before ovulation. Sixty-seven embryo flushings were performed between Days 7 and 9 after ovulation/insemination. Thirteen mares were not flushed, but their uteri were scanned for pregnancy on Days 14 to 16. Embryo recovery rates decreased as time from ovulation to insemination increased, although embryo quality remained normal as evaluated by morphological criteria and mitotic index. However, postovulatory insemination in this trial appeared to delay embryo development, since the embryos recovered from mares inseminated after ovulation were appreciably smaller and at an earlier stage of development than control embryos recovered from mares inseminated prior to ovulation. Part of this delay in embryo development in the postovulation group could be due to the time needed for sperm capacitation. In addition, as the time from ovulation to insemination increased, embryo development might have been further delayed by defects in the aging oocyte.

Journal Article↗
PubMed2000

Synchronization of ovulation in beef cows (Bos indicus) using GnRH, PGF2alpha and estradiol benzoate.

The objective of this study was to evaluate protocols for synchronizing ovulation in beef cattle. In Experiment 1, Nelore cows (Bos indicus) at random stages of the estrous cycle were assigned to 1 of the following treatments: Group GP controls (nonlactating, n=7) received GnRH agonist (Day 0) and PGF2alpha (Day 7); while Groups GPG (nonlactating, n=8) and GPG-L (lactating, n=9) cows were given GnRH (Day 0), PGF2alpha (Day 7) and GnRH again (Day 8, 30 h after PGF2alpha). A new follicular wave was observed 1.79+/-0.34 d after GnRH in 19/24 cows. After PGF2alpha, ovulation occurred in 19/24 cows (6/7 GP, 6/8 GPG, 7/9 GPG-L). Most cows (83.3%) exhibited a dominant follicle just before PGF2alpha, and 17/19 ovulatory follicles were from a new follicular wave. There was a more precise synchrony of ovulation (within 12 h) in cows that received a second dose of GnRH (GPG and GPG-L) than controls (GP, ovulation within 48 h; P<0.01). In Experiment 2, lactating Nelore cows with a visible corpus luteum (CL) by ultrasonography were allocated to 2 treatments: Group GPE (n=10) received GnRH agonist (Day 0), PGF2alpha (Day 7) and estradiol benzoate (EB; Day 8, 24 h after PGF2alpha); while Group EPE (n=11), received EB (Day 0), PGF2alpha (Day 9) and EB (Day 10, 24 h after PGF2alpha). Emergence of a new follicular wave was observed 1.6+/-0.31 d after GnRH (Group GPE). After EB injection (Day 8) ovulation was observed at 45.38+/-2.03 h in 7/10 cows within 12 h. In Group EPE the emergence of a new follicular wave was observed later (4.36+/-0.31 d) than in Group GEP (1.6+/-0.31 d; P<0.001). After the second EB injection (Day 10) ovulation was observed at 44.16+/-2.21 h within 12 (7/11 cows) or 18 h (8/11 cows). All 3 treatments were effective in synchronizing ovulation in beef cows. However, GPE and, particularly, EPE treatments offer a promising alternative to the GPG protocol in timed artificial insemination of beef cattle, due to the low cost of EB compared with GnRH agonists.

Animal Husbandry↗
PubMed1988

Treatment of seasonally anestrous Romney ewes with continuous infusion of low doses of GnRH: effects on estrus, ovulation and plasma progesterone concentration.

The aim of this study was to assess the suitability of a GnRH infusion regimen (125 ng/h or 250 ng/h) to induce estrous behaviour, ovulation and normal corpus luteum function in progesterone-primed Romney ewes each month of seasonal anestrus (i.e. September to February inclusive) over two years. None of the progesterone-primed control ewes (i.e. no GnRH treatment; N = 120 observations) ovulated, showed normal corpus luteum function or displayed estrous behaviour at any time during anestrus. Approximately 27 and 50% of the respective 125 ng/h and 250 ng/h GnRH-treated ewes (N = 120 observations per GnRH treatment) ovulated and showed normal luteal function. Of those which ovulated 59.2% and 52.4% in the respective 125 ng/h and 250 ng/h GnRH treatment groups showed estrous behaviour. There was a significant effect of GnRH dose on the median number of ovulations (250 ng/h > 125 ng/h; P<0.01) but no overall difference (when both treatment years and GnRH doses were pooled) in the median number of ovulations per month of anestrus. The frequency of ewes with an ovulation rate >2 was low with only 4/95 treated ewes with more than 2 corpora lutea (CL). Treatment of progesterone-primed ewes with 250 ng/h GnRH increased plasma LH (P<0.01) but not FSH concentrations; a significant increase in LH pulse amplitude (P<0.05) but not LH pulse frequency was observed. The plasma gonadotropin levels in the 125 ng/h GnRH treatment groups were not studied. We suggest that in breeds such as the Romney which have a strict (i.e. 5-6 month) anovulatory interval, the GnRH-infusion technique may be of limited practical use for inducing pregnancies during the non-breeding season.

Journal Article↗
PubMed1994

Characteristics of follicular evacuation during human ovulation.

Our objectives were to determine the rate and extent of follicular evacuation during human ovulation. Female volunteers were given 5000 or 10,000 IU human chorionic gonadotropin to induce ovulation when a follicle reached 18-20 mm. Ovulations were observed via transvaginal ultrasonography and recorded. Images were digitized for computer-assisted analysis. Areas of the follicles, taken to reflect follicular volume, were measured at specific time intervals from the moment of the first leakage of fluid until complete follicular evacuation. Twenty-five ovulations were visualized. In 23 cases (92%) all of the follicular fluid was expelled, but in two cases the follicle failed to empty completely. In all complete ovulations the initial fluid loss was rapid. The time to reach 70% evacuation was 0.9 +/- 0.3 min (+/- SEM). The remaining fluid leaked out more slowly; the mean time to complete follicular evacuation was 6.1 +/- 1.1 min. There was considerable variability in the rates of ovulation (range 6 s to 18.5 min). An association was observed between the type of stigma formed prior to ovulation and the initial rate of fluid loss. The data provide evidence of variability during follicular evacuation, which may in turn influence the successful expulsion of the oocyte from the follicle.

Journal Article↗
PubMed1999

Fecundity above the Species Level: Ovule Number and Brood Size in the Genisteae (Fabaceae: Papilionoideae).

Per-fruit components of fecundity (ovules per ovary, seeds per fruit, seed : ovule ratio, and patterns of seed maturation within pods) were studied in 33 species of the Genisteae, a legume tribe of mostly Mediterranean shrubs, e.g., Cytisus, Ulex, that also includes more widespread herbs such as Lupinus. Species identity explained most variance in both potential (ovules) and realized (seeds per fruit and seed : ovule ratio) fecundity, and although significant population-specific effects existed, these were relatively small, indicating that estimates of fecundity were not particularly prone to environment-induced changes. Average seed : ovule ratios varied between 20% (for a few species in which fixed rates of embryo abortion result into single seeded pods) and 100% (annuals), but most taxa were in the 40%-60% range. The probability that an ovule near the base of the ovary matured into a seed was significantly lower than the pod average in the majority of species. As indicated by the large size of stigmatic pollen loads, this was unlikely to result from insufficient pollination but rather from preferential embryo abortion. High abortion rates next to pod base occurred in both presumed selfers and obligate outcrossers. Evidence points to relatively stereotyped reproductive ways and high reproductive coherence in the tribe, with major departures from the norm being high seed : ovule ratios exhibited by annual Lupinus (associated with selfing), and low ratios shown by species with single seeded pods (associated with fixed rates of embryo abortion).

Journal Article↗
PubMed2000

Single-dose miconazole nitrate vaginal ovule in the treatment of vulvovaginal candidiasis: two single-blind, controlled studies versus miconazole nitrate 100 mg cream for 7 days.

To determine the efficacy and safety of a single-dose (1200 mg) soft gel insert (vaginal ovule) with miconazole nitrate (2%) topical cream compared with Monistat 7 (miconazole nitrate 2%) Vaginal Cream (Advanced Care Products, North Brunswick NJ) in treating vulvovaginal candidiasis (VVC), two randomized, single-blind, multicenter, controlled, comparative phase III studies were performed. Five hundred fifty-eight patients received either a single-dose miconazole nitrate (1200 mg) ovule or seven consecutive doses of Monistat 7. Ovule arm patients also received miconazole nitrate 2% cream for symptom relief, as needed, up to twice daily. The primary end point was a therapeutic cure. Also evaluated were time to complete symptom relief, safety, and patient preference. The ovule had overall cure rates of 71.7% (71 of 99 patients) and 61.5% (64 of 104 patients). Monistat 7 had overall cure rates of 70.1% (68 of 97 patients) and 61.1% (55 of 90 patients). A significantly greater proportion of patients experienced complete symptom relief by day 3 with the ovule (p = 0.008 and p = 0.025), and time to complete relief was significantly faster (median 4 versus 5 days and 3 versus 4 days). Overall safety results were consistent between groups in both studies. Miconazole nitrate vaginal ovule is as safe and efficacious in curing VVC as Monistat 7 while providing complete symptom relief significantly faster. Patients preferred the ovule to prior therapy.

Administration, Intravaginal↗
PubMed2002

Early ovule development following self- and cross-pollinations in Eucalyptus globulus Labill. ssp. globulus.

The study was conducted to identify the self-incompatibility mechanism in Eucalyptus globulus ssp. globulus. Controlled self- and cross-pollinations were conducted on individual flowers from three mature trees that had self-incompatibility levels of 76, 99.6 and 100%. Flowers were harvested at 4, 6 and 8 weeks after pollination. Embryology was investigated by bright field microscopy on material harvested at 4 and 6 weeks after pollination. Fertilization had taken place at 4 weeks after pollination with zygotes and free nuclear endosperm visible. There was a greater proportion of healthy, fertilized ovules in the cross- compared with the self-pollination treatment, and approx. half the ovules examined from both pollen treatments were not fertilized or were degenerating. By 6 weeks after pollination a few zygotes were starting to divide. The number of healthy, fertilized ovules was still greater in the cross-pollination treatment, but the number of healthy fertilized ovules was lower in both treatments compared with 4 weeks after pollination, and many ovules were degenerating. Fertilized ovules were significantly larger than non-fertilized or degenerating ovules and this difference was detectable by eye at 6 and 8 weeks after pollination. The mechanism of self-incompatibility appears to have both late pre- and post-zygotic components.

Algorithms↗
PubMed1995

The Arabidopsis SUPERMAN Gene Mediates Asymmetric Growth of the Outer Integument of Ovules.

Arabidopsis superman (sup, also referred to as floral mutant10) mutants have previously been shown to have flowers with supernumerary stamens and reduced carpels as a result of ectopic expression of the floral homeotic gene APETALA3 (AP3). Here, we report that sup mutations also cause specific alterations in ovule development. Growth of the outer integument of wild-type ovules occurs almost exclusively on the abaxial side of the ovule, resulting in a bilaterally symmetrical hoodlike structure. In contrast, the outer integument of sup mutant ovules grows equally on all sides of the ovule, resulting in a nearly radially symmetrical tubular shape. Thus, one role of SUP is to suppress growth of the outer integument on the adaxial side of the ovule. Genetic analyses showed that the effects of sup mutations on ovule development are independent of the presence or absence of AP3 activity. Thus, SUP acts through different mechanisms in its early role in ensuring proper determination of carpel identity and in its later role in asymmetric suppression of outer integument growth.

Journal Article↗
PubMed1998

GENETIC ANALYSIS OF OVULE DEVELOPMENT.

Ovules are the direct precursors of seeds and thus play central roles in sexual plant reproduction and human nutrition. Extensive classical studies have elucidated the evolutionary trends and developmental processes responsible for the current wide variety of ovule morphologies. Recently, ovules have been perceived as an attractive system for the study of genetic regulation of plant development. More than a dozen regulatory genes have now been identified through isolation of ovule mutants. Characterization of these mutants shows that some aspects of ovule development follow independent pathways, while other processes are interdependent. Some of these mutants have ovules resembling those of putative ancestors of angiosperms and may help in understanding plant evolution. Clones of several of the regulatory genes have been used to determine expression patterns and putative biochemical functions of the gene products. Newly constructed models of genetic regulation of ovule development provide a framework for interpretation of future discoveries.

Journal Article↗
PubMed1998

Pattern formation and growth during floral organogenesis: HUELLENLOS and AINTEGUMENTA are required for the formation of the proximal region of the ovule primordium in Arabidopsis thaliana.

Our understanding of the molecular mechanisms that regulate and integrate the temporal and spatial control of cell proliferation during organ ontogenesis, particularly of floral organs, continues to be primitive. The ovule, the progenitor of the seed, of Arabidopsis thaliana has been used to develop an effective model system for the analysis of plant organogenesis. A typical feature of a generalized ovule is the linear arrangement of at least three distinct elements, the funiculus, chalaza and nucellus, along a proximal-distal axis. This pattern is supposed to be established during the early proliferative phase of ovule development. We provide genetic evidence that the young ovule primordium indeed is a composite structure. Two genes, HUELLENLOS and AINTEGUMENTA have overlapping functions in the ovule and differentially control the formation of the central and proximal elements of the primordium. The results indicate that proximal-distal pattern formation in the Arabidopsis ovule takes place in a sequential fashion, starting from the distal end. Furthermore, we show that HUELLENLOS also regulates the initiation and/or maintenance of integument and embryo sac ontogenesis and interestingly prevents inappropriate cell death in the young ovule.

Arabidopsis↗
PubMed2004

Protein patterns of the Brassica rapa ovules and seeds under altered gravity.

Electrophoretic investigation of protein patterns of Brassica rapa L. ovules and seeds from plants grown under clinorotation and in the laboratory control was carried out. Ovules at different stages (7 and 18 days after pollination) and mature seeds were analyzed. Polymorphism of seed storage proteins of B. rapa was taken into consideration in analysis of changes in ovule protein patterns under clinorotation. The appearance of a protein component in the region of about 43 kDa was detected in protein patterns of 7-day-old and 18-day-old ovules in the clinostat variants. Under altered gravity, in 18-day-old ovules, the appearance of a protein in the region of about 70 kDa was also revealed. The appearance of the protein component with the similar mobility (about 43 kDa) in ovules of different age from plants grown at clinorotation suggests that synthesis of this protein may be associated with the plant response to altered gravity. However, the investigation of the nature of this protein and its role requires further research to rule out its appearance because of genotypic differences between ovules of the control and experimental variants.

2S Albumins, Plant↗
PubMed1977

Plasma hormones in human gonadotropin induced ovulation.

Plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrone (E1), estradiol-17beta(E2), progesterone (P), androstenedione (A), and testosterone (T) were analyzed in daily plasma samples of seven cycles of human menopausal gonadotropin (hMG)-human chorionic gonadotropin (hCG) induced ovulation. Plasma FSH rose gradually and remained at a higher level (20 to 30 mlU/ml) during hMG injection while LH stayed at a low tonic level. The FSH/LH ratio of plasma gonadotropins was consistently higher than 1 in spite of injecting an hMG preparation with FSH/LH ratio of 1. A pharmacologically induced high RSH/LH ratio in the late follicular phase is contradictory to the low ratio seen in the normal ovulatory cycle. This may be one of the causes of multiple follicular maturation and ovulation frequently encountered in the hMG-hCG induced ovulation. Higher than normal levels of plasma progesterone commonly seen in the hMG-hCG induced cycle is attributed to the multiple ovulation. Plasma androgen levels, both A and T, in these therapy cycles stayed consistently within normal range. This is a strong contrast to the clomiphene induced cycle in which A and T were frequently elevated in parallel with elevated LH. No significant differences in plasma hormones were observed between the pregnant and nonpregnant patient following hMG-hCG induced ovulation. A consistent and similar ovarian response to hMG-hCG was noted in 1 individual who had 3 consecutive therapy cycles studied. The plasma hormone levels in the multiple ovulation did not show a significant difference from those in the single ovulation with the exception of a higher plasma P level in the former.

Adult↗