Normal Eggs Research Articles

Cytological studies on induced meiogynogenesis in Japanese flounderParalichthys olivaceus(Temminck et Schlegel)

The cytological process of induced gynogenetic development and subsequent chromosome duplication by a cold shock treatment was observed in Japanese flounder Paralichthys olivaceus (Temminck et Schlegel). Mature eggs were at the metaphase of the second meiosis when inseminated with ultraviolet (UV)-irradiated sperm of red sea bream Pagrus major. After the beginning of cold shock treatment, the previously visible spindle became invisible, probably due to the side effect caused by cold shock treatment. The chromosomes at the centre of the metaphase plate were condensed. This condition continued during the duration of the cold shock treatment and several minutes after it. The release of the second polar body was blocked and it developed into a female-like pronucleus. Then, it fused with the female pronucleus to generate a diploid zygotic nucleus, and the egg exhibited the first mitosis. Consequently, the haploid female chromosome set of the egg was doubled by the inhibition of the second polar body release. There was a significant delay in developmental time in the gynogenetic eggs when compared with that in the normal eggs. From the time of insemination to early cleavage, the UV-irradiated heterospecific sperm nucleus remained condensed.

Deuterium for Estimating Total Body Water and Turnover Rates in Turkeys Exposed to Different Incubation Treatments

Total water intake (TWI) in poultry can be influenced by various factors. Recommendations for water requirements are usually reported on a flock basis without considering individual variation. In the present study, a total of 18 turkeys were used to measure water intake over a 1-wk period starting at 15 wk of age by applying the deuterium dilution technique. Poults originated from eggs exposed to different incubation treatments, with eggs incubated at normal temperature (37.5 degrees C) and eggs subjected to 38.5 degrees C at embryonic d 9 to 12. Experimental birds were kept in flocks of 22 to 30 birds separated by sex and treatment. Feed and water were provided ad libitum. Incubation treatment had no significant effect on any of the parameters investigated (BW, daily gain, water turnover rate, total body water, TWI), whereas sex exerted a significant effect on nearly all traits. Total body water ranged between 60 and 65% of BW, with significantly (P < 0.05) greater values for toms (63.2%) than for hens (60.9%). Males had approximately 30% greater water influxes than females (1,054 +/- 198 vs. 742 +/- 153 mL/d, mean +/- SD). However, the significant influence of sex was eliminated (P = 0.464) when TWI was expressed as grams per kilogram of BW (76 +/- 18 vs. 70 +/- 12 mL/kg of BW; males vs. females). Water consumed averaged 837 mL in male and 569 mL per day in female birds. The present results suggest that the isotope dilution method offers a viable method to measure individual water intake, which can be used for establishing reference values for water consumption in group-housed turkeys.

The effect of a rise or fall in the serum estradiol level prior to egg retrieval on outcome of in vitro fertilization-embryo transfer cycles in women with diminished egg reserve

The effect of a rise or fall in the serum estradiol level prior to egg retrieval on outcome of in vitro fertilization-embryo transfer cycles in women with diminished egg reserve

30 Years of IVF: What Does the Future Hold?

The publication of the first successful human birth after IVF-embryo transfer (IVF-ET) in 1978 revolutionized the infertility industry [1]. The original technique involved oocyte retrieval in a natural ovulatory cycle. The tools for retrieval and the culture medium for embryos were rather primitive compared with those used today, hence, initial pregnancy rates were low. In addition, despite careful monitoring, there were often times when the one egg could be released without being ‘caught’. This combination of factors resulted in low pregnancy rates [2,3]. The pervading thoughts at this time were that in a given cohort of antral follicles, some of the oocytes would be genetically normal whilst some would have meiosis errors, and it would be merely fortuitous if the follicle containing a genetically normal egg became dominant. Thus, stimulating multiple follicles with clomiphene citrate alone or with clomiphene and human menopausal gonadotropin, became the usual method for preparing oocyte retrieval [4]. An even greater recruitment of follicles could be achieved by the use of gonadotropin stimulation instead of clomiphene. This would not only allow more fresh embryos to be transfered, but also produce extra embryos that could be cryopreserved for future use [5]. Thus, one could try to maximize the success from one expensive oocyte harvest (cost of medications, monitoring, oocyte retrieval and anesthesia) by performing a much less expensive frozen-embryo transfer in case of failure to achieve a pregnancy with the fresh-embryo transfer [6]. Unfortunately, in approximately 20% of the cycles, the high serum estradiol levels generated by the expensive gonadotropins caused premature luteinization and, thus, cancellation of

Induction of gynogenesis in stellate sturgeon (Acipenser stellatusPallas, 1771) and its verification using microsatellite markers

Normal egg fertilization was carried out in stellate sturgeon Acipenser stellatus sperm by 60-, 90- and 120-s ultraviolet irradiation, and a cold shock was carried out afterwards. The treatments included haploids, diploid gynogens, triploid and control groups. Fertilization, hatching and survival rate at the 60-s irradiation time were significantly greater than those in the 90-s and 120-s irradiation and control groups. Two pairs of microsatellite markers were used to find gynogenesis in comparison with the parental and offspring genome in one locus. The results showed all maternal genomes among gynogen offspring with no paternal genome. The markers also showed the maximum gynogenesis induction in the Gy60 treatment.

A Matched Control Study of Pregnancy Rates Following In Vitro Fertilization–Embryo Transfer in Women Aged ≤37 Years With Diminished Versus Normal Egg Reserve

A Matched Control Study of Pregnancy Rates Following In Vitro Fertilization–Embryo Transfer in Women Aged ≤37 Years With Diminished Versus Normal Egg Reserve

Abnormal Eggs of Rio Grande Wild Turkeys on the Edwards Plateau, Texas

Abstract We studied the reproductive ecology of Rio Grande Wild Turkeys (Meleagris gallopavo intermedia) in the Edwards Plateau region, Texas during 2005 and 2006. Runt eggs from a single adult female were observed through three nesting events over 2 years. Mean mass and volume for the runt eggs were 44% of normal Wild Turkey eggs. Production of runt eggs is common in domesticated gallinaceous birds, yet little information is available on runt egg production in wild gallinaceous birds. To our knowledge, our observations are the first which indicate runt egg production occurs in Wild Turkeys.

Sperm nuclear expansion and meiotic maturation in normal and gynogenetic eggs of the scallop, Chlamys farreri

Sperm nuclear expansion, meiosis and the association of the male and female pronuclei leading to the four-cell stage in normal Chlamys farreri eggs were observed under a fluorescence microscope. The effects of ultraviolet (UV) irradiation on the fertilizing sperm were also examined. Both normal and UV-irradiated sperm nuclei enlarged at three distinct phases (phase A, metaphase I; phase B, polar body formation; and phase C, female pronuclear development and expansion) that were temporally correlated with meiotic process of the maternal chromosomes. Sperm nuclei underwent a rapid, initial enlargement during phase A, but condensed slightly during phase B, then re-enlarged during phase C. The effects of UV irradiation were not apparent during transformation of the sperm nucleus into a male pronucleus, and there was not any apparent effect on meiotic maturation and development of the female pronucleus. However, the rate of expansion of the UV-irradiated sperm nuclei and the size of male pronuclei were reduced apparently. Unlike the female pronucleus, the male pronucleus derived from sperm genome inactivated by UV irradiation did not form chromosomes, but became a dense chromatin body (DCB). At mitotic anaphase, DCB did not participate in the karyokinesis of the first cleavage as evidenced by chromosomal nondisjunction, demonstrating the effectiveness of using UV irradiation to induce gynogenetic scallop embryos.

Intraperitoneal and dorsal median sinus vaccination effects on growth, immune response, and reproductive potential in farmed Atlantic salmon Salmo salar

Intra-abdominal adhesions resulting from ip vaccination affect ovaries and may have an impact on broodstock fecundity and egg quality. The effects of ip and dms vaccination on reproductive success and immune protection in Salmo salar were compared. Cumulative mortalities for 12–16 weeks post vaccination were 1–5% in range for ip vaccinated fish and 0.5–1% in dms fish. Growth of vaccinated fish in both groups dipped for 3 to 6 weeks post vaccination but pre transfer growth did not differ. Vaccine induced lesions from ip vaccination were mild and did not affect oocyte development, with mean score values from 0.95–1.03 and melanin deposition of 1.5–1.7. High antibody titres to A. salmonicida ssp salmonicida were present in all fish 16 weeks after vaccination by either the dms or ip route. In bacterial challenge rps was over 98% and there was no significant difference in immune protection with dms or ip vaccination. Broodstock vaccinated ip showed minor grade adhesions affecting the ovary on spawning but residual eggs were stripped easily by hand. A mean gonadosomatic index of 38.8% was higher in the ip vaccinated fish as was relative fecundity at 1999 eggs kg−1. The percentage of normal viable eggs at 180 degree days development did not differ between vaccination routes at 70% in dms and 68% in ip fish respectively. It is concluded that, although ovaries of ip vaccinated fish displayed adhesions, egg production and viability were not affected.

Exogenous hormones induce poor rates of oviposition in the anurans, Litoria moorei and L. aurea

Combinations of commercially available hormones (luteinising hormone-realeasing hormone agonist, human chorionic gonadotrophin and progesterone) were given intra-coelomically to gravid females of two Australian bell frogs, Litoria moorei and L. aurea. The injections were not sufficient to cause normal ovulation and egg laying in the absence of males. Further studies are still required to develop a safe method of programming ovulation and oviposition in these and other recalcitrant species to obtain eggs that have not been exposed to sperm.

Mild ovarian stimulation

To evaluate the efficacy of using only mild ovarian stimulation protocols for in vitro fertilization. Both groups with decreased and normal ovarian reserve were evaluated. Three different mild stimulation protocols were evaluated: natural with no exogenous follicle stimulation hormone (FSH) drugs at all, natural with a boost of low dose FSH to complete follicular maturation, and minimal stimulation with low dose (75-150IU) FSH from day 3-5 of the menstrual cycle. Ethinyl estradiol was sometimes used to lower high day 3 serum FSH. Good pregnancy and implantation rates were found even in those women with elevated serum FSH that could only generate one follicle. Mild ovarian stimulation seems preferable to high dose FSH regimens in women with elevated day 3 serum FSH based on previous poor reported pregnancy rates with the latter protocols. Comparable pregnancy rates to high dose regimen were seen in women with normal egg reserve at much lower risk and cost.

Effect of egg shape index on mechanical properties of chicken eggs

Eggs are available in different shapes. These shapes can be differentiated using a shape index (SI). The shapes most often encountered are sharp, normal (standard), and round eggs which are enumerated on the SI as <72, 72–76, and >76, respectively. In this study, the effect of egg shape on the mechanical behaviour of chicken eggs under a compression load was investigated. The resistance of chicken eggs (Lohmann) to damage was determined by measuring the average rupture force, specific deformation, rupture energy and firmness along the X-front ( X f), X-back ( X b) and Z-axes at different compression speeds (0.33, 0.66 and 0.99 mm/s). The greatest amount of force required to break the eggs was required when eggs were loaded along the X f-axis and the least compression force was required along the Z-axis. The specific deformation and rupture energy required for the eggs tested was lower along the X f-axis than the X b- or Z-axes. The highest measure of firmness in the eggs tested was found to be along their X f-axis. The results indicated that when testing the effects of compression speed the rupture force is highly dependent on SI. The greatest force needed to rupture eggs was found in eggs with high SI values that were tested at low compression speeds.

Recognition of vertebrate egg abnormalities in the Upper Cretaceous fossil record

In fossil vertebrate eggs, the most commonly reported abnormality consists of an unusually thick shell with one or more superimposed eggshell layers. Although rare, taxonomically referable abnormal specimens provide a more reliable basis for inferences regarding reproductive biology of extinct taxa. Eggshell abnormalities recognized in a Cretaceous turtle and three dinosaurs (hadrosaur, sauropod, theropod) are assigned to these taxa base on: 1) normal eggs containing embryos within the same clutch, 2) identical eggshell microstructure as eggs containing embryonic remains from the same stratum; and 3) inclusion of normal eggs of the same oospecies in a cladistic analysis of egg characters. Distinguishing multiple eggshell layers of biological origin from those produced by taphonomic processes is a critical component in the study of fossil specimens. Features useful for distinguishing a pathological condition in fossil eggs include: 1) multiple eggshell layers separated by permineralized membrane, 2) close conformation of the base of the outer eggshell to the unweathered surface of the underlying egg, and 3) structural relationships of eggshell features (e.g. pore truncation, intercalated membrane and shell fragments, optical continuity of superimposed fragments). Documentation of microstructural features of abnormal eggshell provides important information on the timing and magnitude of stress and facilitates recognition of phylogenetically significant patterns of egg abnormality in the fossil record.

Obligate symbiont involved in pest status of host insect.

The origin of specific insect genotypes that enable efficient use of agricultural plants is an important subject not only in applied fields like pest control and management but also in basic disciplines like evolutionary biology. Conventionally, it has been presupposed that such pest-related ecological traits are attributed to genes encoded in the insect genomes. Here, however, we report that pest status of an insect is principally determined by symbiont genotype rather than by insect genotype. A pest stinkbug species, Megacopta punctatissima, performed well on crop legumes, while a closely related non-pest species, Megacopta cribraria, suffered low egg hatch rate on the plants. When their obligate gut symbiotic bacteria were experimentally exchanged between the species, their performance on the crop legumes was, strikingly, completely reversed: the pest species suffered low egg hatch rate, whereas the non-pest species restored normal egg hatch rate and showed good performance. The low egg hatch rates were attributed to nymphal mortality before or upon hatching, which were associated with the symbiont from the non-pest stinkbug irrespective of the host insect species. Our finding sheds new light on the evolutionary origin of insect pests, potentially leading to novel approaches to pest control and management.

Biological Evaluation of Normal and Low Cholesterol Eggs

Biological Evaluation of Normal and Low Cholesterol Eggs

The MEK inhibitor, U0126, alters fertilization-induced [Ca 2+] i oscillation parameters and secretion: Differential effects associated with in vivo and in vitro meiotic maturation

Although mitogen-activated protein kinase (MAPK) is a well-known cell cycle regulator, emerging studies have also implicated its activity in the regulation of intracellular calcium concentration ([Ca 2+] i) and secretion. Those studies raise the hypothesis that MAPK activity during oocyte maturation and early fertilization is required for normal egg Ca 2+ oscillations and cortical granule (CG) secretion. We extend the findings of [Lee, B., Vermassen, E., Yoon, S.-Y., Vanderheyden, V., Ito, J., Alfandari, D., De Smedt, H., Parys, J.B., Fissore, R.A., 2006. Phosphorylation of IP 3R1 and the regulation of [Ca 2+] i responses at fertilization: a role for the MAP kinase pathway. Development 133, 4355–4365] by demonstrating acute effects on Ca 2+ oscillation frequency, amplitude, and duration in fertilized mouse eggs matured in vitro with the MAPK inhibitor, U0126. Frequency was increased, whereas amplitude and duration were greatly decreased. These effects were significantly reduced in eggs matured in vivo and fertilized in the presence of the inhibitor. Ionomycin studies indicated that intracellular Ca 2+ stores were differentially affected in eggs matured in vitro with U0126. Consistent with these effects on [Ca 2+] i elevation, fertilization-induced CG exocytosis and metaphase II exit were also reduced in in vitro-matured eggs with U0126, but not in those similarly treated after in vivo maturation. These results indicate that MAPK targets Ca 2+ regulatory proteins during both maturation and fertilization, as well as provide a new hypothesis for MAPK function, which is to indirectly regulate events of early development by controlling Ca 2+ oscillation parameters.

Molecular characterization, tissue-specific expression and RNAi knockdown of the first vitellogenin receptor from a tick

This is the first full-length message for a vitellogenin receptor (VgR) sequenced from ticks. VgRs, members of the low-density lipoprotein receptor (LDLR) superfamily, mediate the uptake of the yolk protein, vitellogenin (Vg), from the hemolymph. The VgR message from the American dog tick, Dermacentor variabilis (GenBank accession No. DQ103506.4) comprised 5673 bp which coded for a 1798 aa deduced protein with a predicted 196.6 kDa molecular mass. After removing the 20 aa signal peptide, the 1778 aa deduced mature protein had a predicted 196.6 kDa molecular mass. BLAST comparisons showed the highest similarity to the VgR of the cockroach, Periplaneta americana. VgR message was expressed in mated female ovary but absent in female midgut and salivary glands or whole body mRNA from blood fed males, indicating that it is both sex and tissue specific. VgR transcript was absent in virgin (previtellogenic) females but present in ovaries of mated females following drop off. RNAi showed that unfed adult ticks injected with a VgR-dsRNA probe failed to lay eggs, develop brown eggs or fully express VgR transcript (Northern blots). In contrast, controls oviposited numerous normal brown eggs and showed strong expression of VgR transcripts. These results show that the expression of the VgR message is essential for Vg uptake and egg development in the American dog tick.

Schistosome egg production is dependent upon the activities of two developmentally regulated tyrosinases

Egg production is responsible for life cycle progression and host immunopathology during schistosomiasis, with the associated parasite molecules being investigated as potential novel chemotherapeutic targets. Here, we characterize two Schistosoma mansoni products, tyrosinase 1 and tyrosinase 2 (SmTYR1/SmTYR2) and show that their diphenol oxidase enzyme activities are critical for eggshell formation and production. The genes encoding these bifunctional enzymes (monophenol and diphenol oxidases) result from a duplication event that likely occurred before speciation and exist in the parasite's genome as multiple copies, which are linked and localized to chromosomes 4 and W. SmTYR1/SmTYR2 transcription and diphenol oxidase action are developmentally regulated with most enzyme activity localized to the eggshell-producing cells contained within the vitellaria of adult female worms. Importantly, kojic-acid mediated inhibition (IC50=0.5 microM) of SmTYR1/SmTYR2's diphenol oxidase activity during in vitro culture of sexually mature adult worms resulted in a significant decrease in the production of phenotypically normal eggs. Therefore our data suggest that SmTYR1/2 inhibition represents a novel and potentially effective strategy for combating schistosomiasis and furthermore, it may point to new methods for combinatorial control of immunopathology and egg transmission during platyhelminth infection.

O-277: Lupron trigger experience in GnRH antagonist ART cycles: Not a panacea

To determine the ability of a GnRH agonist to trigger final egg maturation and reduce the risk of ovarian hyperstimulation in GnRH-antagonist controlled IVF and Donor Egg cycles. Retrospective Cohort. A “Lupron Trigger” was used in 85 cases from June 2004 until October 2005 when the risk of OHSS was judged to be high. A single dose of Lupron (leuprolide acetate) 2 mg was given SC (in place of hCG 5,000 IU) 35 hours before planned egg retreival. Luteal support was begun the day after egg retrieval (progesterone (P4) 50 mg IM daily and estradiol (E2) 2 mg PO bid). Fifteen cycles were Egg Donor; 70 were standard IVF. In 17 cases a prior cycle in which hCG had been used as a trigger was available for comparison (of which 7 were donor egg cycles). Results are given as mean ± standard deviation. At the time of the trigger, E2 was 3821 pg/mL (±1327) and the number of follicles larger than 10 mm was 29.6 (±9.7). The morning after the Lupron Trigger, the mean LH was 54.2 IU/L (±29.9) and P4 was 8.9 ng/mL (±4.5). After use of a Lupron Trigger: 1. None of the 85 cases developed any degree of OHSS despite being high risk. 2. In three cases there was an aberrant surge response [case 1: LH 2.2 IU/L, P4 12.8 ng/mL, 22 eggs but none fertilized; case 2: LH 8.0 IU/L, P4 5.5 ng/mL, 23 eggs of which only 2 were mature; case 3: LH 10 IU/L, P4 1.2 ng/mL, no eggs from first 5 aspirates]. In 6 other cases, despite an adequate surge response, many fewer than expected eggs were obtained (n=3: 9 eggs from 23 large follicles, 20 from 50, 24 from 60), or few were mature (n=4: 2 of 23, 0 of 23, 4 of 21, 11 of 20), and/or few fertilized (n=5: 3 of 11, 1 of 9, 2 of 11, 1 of 16, 1 of 24). 3. In the fresh IVF cycles with transfer (n=57), implantation rate was 16.9%, 44% had a clinical pregnancy, 33% miscarried, and 29% have ongoing or delivered pregnancies. However, these disappointing outcomes were not seen in either the Donor Egg cases (of 15 transfers, the implantation rate was 63%; 77% became clinical pregnant and none have miscarried) or the subsequent cryo-thaw cycles of the initial IVF cases (of 13 transfers, the implantation rate was 59.4%; 76.9% became pregnant and 61.5% are ongoing or delivered). 4. The paired analysis (n=17) showed lower egg yield in the Lupron Trigger cases (58% of follicles 13 mm or larger yielded an egg) vs. the hCG trigger cases (79%). Use of the Lupron Trigger reduces (if not eliminates) the risk of OHSS. However, the Lupron Trigger failed to induce normal final egg maturation in 10 of 85 cases. Moreover, the yield of eggs was reduced in the paired analysis, and pregnancy outcomes were low in the fresh IVF (but not Donor Egg or frozen IVF) cycles. This descrepancy suggests an endometrial defect with use of the Lupron Trigger. We advise caution in adopting the Lupron Trigger as the primary strategy to avert OHSS in antagonist controlled cycles.

Egg Coloration and Recognition of Conspecific Brood Parasitism in Eastern Bluebirds

AbstractIndividual eastern bluebird (Sialia sialis) females produce clutches of eggs with unique coloration and older females and females in better body condition lay more pigmented blue‐green eggs. Conspecific brood parasitism in this species is not uncommon and bluebirds occasionally reject what appear to be normal eggs by moving them to the periphery of the nest. I used UV‐visual reflectance spectrometry to objectively measure coloration of eggs and nest material. To estimate the conspicuousness of the trait, I calculated the contrast between eggs and background nest material. I found high achromatic and chromatic contrast between the coloration of eggs and of the nests, suggesting that bluebird eggs are highly conspicuous. To test the hypothesis that expression of blue‐green coloration eggs facilitates recognition of eggs laid by conspecific brood parasites, I cross‐fostered individual eggs into host nests during egg laying and monitored the fate of those eggs. I found no support, however, for the hypothesis that egg coloration facilitates discrimination of parasitic eggs from host eggs.