Molecular forms of BMP15 and GDF9 in mammalian species that differ in litter size.

Bone morphogenetic protein (BMP15) and growth differentiation factor (GDF9) are critical for ovarian follicular development and fertility and are associated with litter size in mammals. These proteins initially exist as pre-pro-mature proteins, that are subsequently cleaved into biologically active forms. Thus, the molecular forms of GDF9 and BMP15 may provide the key to understanding the differences in litter size determination in mammals.

The Crazy Ovary.

From fetal life until senescence, the ovary is an extremely active tissue undergoing continuous structural and functional changes. These ever-changing events are best summarized by a quotation attributed to Plato when describing motion in space and time-'nothing ever is but is always becoming…'. With respect to the ovary, these changes include, at the beginning, the processes of follicular formation and thereafter those of follicular growth and atresia, steroidogenesis, oocyte maturation, and decisions relating to the number of mature oocytes that are ovulated for fertilization and the role of the corpus luteum.

Selection and characterisation of triclosan-specific aptamers using a fluorescence microscope-imaging assay.

This study reports a fluorescence microscope-imaging assay for determining the binding characteristics of single-stranded DNA aptamers selected against the antibacterial agent, triclosan. The imaging assay utilises fluorescently labelled aptamers and target-immobilised matrices. Upon binding of triclosan-specific aptamers to triclosan-conjugated matrices, the binding complex was visualised and the image was captured with the aid of a fluorescence microscope.

The follicular microenvironment in low (++) and high (I+B+) ovulation rate ewes.

Ewes with single copy mutations in GDF9, BMP15 or BMPR1B have smaller preovulatory follicles containing fewer granulosa cells (GC), while developmental competency of the oocyte appears to be maintained. We hypothesised that similarities and/or differences in follicular maturation events between WT (++) ewes and mutant ewes with single copy mutations in BMP15 and BMPR1B (I+B+) are key to the attainment of oocyte developmental competency and for increasing ovulation rate (OR) without compromising oocyte quality. Developmental competency of oocytes from I+B+ animals was confirmed following embryo transfer to recipient ewes.

Molecular forms of ruminant BMP15 and GDF9 and putative interactions with receptors.

Bone morphogenetic factor 15 (BMP15) and growth differentiation factor 9 (GDF9) are oocyte-secreted factors with demonstrable effects on ovarian follicular development and ovulation rate. However, the molecular forms of BMP15 and GDF9 produced by oocytes remain unclear. The aims herein, using Western blotting (WB) procedures with specific monoclonal antibodies (mabs), were to identify the molecular forms of BMP15 and GDF9 synthesised and secreted by isolated ovine (o) and bovine (b) oocytes The mabs were known to recognise the biological forms of BMP15 or GDF9 since they had previously been shown to inhibit their bioactivities and Using recombinant variants of oBMP15 and oGDF9, including a cysteine mutant form of oBMP15 (S356C) and a human (h) BMP15:GDF9 heterodimer (cumulin), it was established that the mabs were able to identify monomeric, dimeric, promature and higher-molecular-weight forms of BMP15 and GDF9 and cumulin (GDF9 mab only).

Unique oestrogen receptor ligand-binding domain sequence of native parrots: a possible link between phytoestrogens and breeding success.

The New Zealand (NZ) native parrots kākāpō, kākā and kea are classified as critically endangered, endangered and vulnerable respectively. Successful reproduction of kākāpō and kākā is linked to years of high levels of fruiting in native flora (mast years). To assess a possible hormonal link between native plants and reproductive success in these parrots in mast years, we examined the ligand-binding domains (LBD) of the progesterone receptor (PR), androgen receptor (AR), estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2) in NZ native (kākāpō, kākā, kea and kākāriki) and non-native (Australian cockatiel) parrots and compared them with those in the chicken.

A protective role of cumulus cells after short-term exposure of rat cumulus cell-oocyte complexes to lifestyle or environmental contaminants.

Ovarian follicular fluid provides a potential reservoir for exogenous compounds that may adversely affect oocyte quality. This study examined the effects of common lifestyle and environmental contaminants, namely bisphenol-A (BPA), caffeine, 3,4-methylenedioxymethamphetamine (MDMA), nicotine and Δ-tetrahydrocannabinol (THC) on gap junction genes (Gja1, Gja4) and proteins (GJA1), glucose metabolism genes (Gfpt1, Pfkp) and oocyte growth factor genes (Bmp15, Gdf9), as well as gap junction transfer rate, in rat cumulus-oocyte complexes (COCs). In vitro exposure to MDMA and THC accelerated the timing of meiotic resumption and all contaminants altered either gap junction gene expression (BPA, caffeine, MDMA and THC) or transfer rate (BPA and nicotine).

Ovarian characteristics in sheep with multiple fecundity genes.

Ewes heterozygous for combinations of the Inverdale (FecX; I+), Booroola (FecB; B+) and Woodlands (FecX2; W+) mutations have ovulation rates higher than each mutation separately. The aims of the experiments described herein were to examine the ovarian phenotypes in I+B+ and I+B+W+ ewes and to compare these with the appropriate ++ (controls), I+ and BB animals available for this study. The mean ± s.

Activin A and follistatin during the oestrous cycle and early pregnancy in ewes.

The activin pathway has been postulated to be involved in regulation of multiple reproductive processes important for survival of the conceptus. These processes include luteinisation of the follicular cells and thus function of the corpus luteum, early embryo development and uterine function including implantation of the conceptus. Therefore, the aim of the current study was to determine whether the concentrations of activin A and follistatin (FST), an activin-binding protein, differed between ewes with a lifetime history of enhanced or reduced embryonic survival (ES).

The in-vitro effects of cAMP and cGMP modulators on inter-cellular dye transfer and gene expression levels in rat cumulus cell--oocyte complexes.

Supplementation of in-vitro maturation medium with reagents that inhibit meiotic resumption whilst supporting normal function of cumulus cell-oocyte complexes (COC) is challenging. This study compared the in-vitro effects of synthetic and physiologically-relevant reagents on meiotic resumption, gap junction activity and gene expression of rat COC. Higher doses of forskolin reduced gap junction activity.

Ultrasensitive colorimetric detection of 17β-estradiol: the effect of shortening DNA aptamer sequences.

We report a strategy enabling ultrasensitive colorimetric detection of 17β-estradiol (E2) in water and urine samples using DNA aptamer-coated gold nanoparticles (AuNPs). Starting from an established sensor format where aggregation is triggered when target-bound aptamers dissociate from AuNP surfaces, we demonstrated that step-change improvements are easily accessible through deletion of excess flanking nucleotides from aptamer sequences. After evaluating the lowest energy two-dimensional configuration of the previously isolated E2 binding 75-mer aptamer (KD ∼25 nM), new 35-mer and 22-mer aptamers were generated with KD's of 14 and 11 nM by simply removing flanking nucleotides on either side of the inner core.

Signalling pathways involved in the synergistic effects of human growth differentiation factor 9 and bone morphogenetic protein 15.

Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) act synergistically to regulate granulosa cell proliferation and steroid production in several species. Several non-Sma and mothers against decapentaplegic (SMAD) signalling pathways are involved in the action of murine and ovine GDF9 and BMP15 in combination, with the pathways utilised differing between the two species. The aims of this research were to determine if human GDF9 and BMP15 also act in a synergistic manner to stimulate granulosa cell proliferation and to identify which non-SMAD signalling pathways are activated.

The microenvironment of the ovarian follicle in the postpartum dairy cow: effects on reagent transfer from cumulus cells to oocytes in vitro.

This study's hypothesis was that the nutrient composition in follicular fluid (FF) of ovarian follicles in early lactating postpartum cows may influence reagent transfer from cumulus cells (CC) to the oocyte. To test this, concentrations of amino acids (AA), cholesterol, glucose, and nonesterified fatty acids were measured in FF from the largest antral follicles at Days 21 and 46 postpartum during which time, most animals were expected to have resumed ovulatory activity. From the range of concentrations measured, two media compositions (Lac and Half-Lac) were prepared to compare with medium 199 (M199).

Small molecule detection in solution via the size contraction response of aptamer functionalized nanoparticles.

We demonstrate a simple new sensor design that exploits aptamer functionalized nanoparticles (NPs) to transduce the signal of aptamer receptors binding to target small molecules. An aptamer capable of binding to our target 17β-estradiol (E2) was isolated by SELEX with dissociation constant of 50 nM and tethered to the surface of carboxylated polystyrene NPs. Upon exposing the aptamer functionalized NPs to E2 in buffered water, we use dynamic light scattering (DLS) and resistive pulse sensing (TRPS) to observe a distinct reduction of the conjugated particle size and a less negative zeta potential, which can be correlated to the E2 concentration in the lower nanomolar range.

Oocyte expression, secretion and somatic cell interaction of mouse bone morphogenetic protein 15 during the peri-ovulatory period.

Bone morphogenetic protein 15 (BMP15) is a key intraovarian growth factor regulating mammalian fertility, yet expression and localisation of different BMP15 protein forms within ovarian follicles around the time of the preovulatory LH surge remains unclear. Using immunoblotting and immunocytochemistry, the present study identified that post-translationally processed BMP15 proregion and mature proteins are increasingly expressed and localised with cumulus and granulosa cells from mice treated with pregnant mare's serum gonadotropin (PMSG) + human chorionic gonadotrophin (hCG). However, this increased expression was absent in cumulus-oocyte complexes matured in vitro.

Aberrant GDF9 expression and activation are associated with common human ovarian disorders.

Context: Growth differentiation factor 9 (GDF9) is a central regulator of folliculogenesis and ovulation rate. Fourteen mutations in human (h) GDF9 have been reported in women with premature ovarian failure or polycystic ovarian syndrome as well as in mothers of dizygotic twins, implicating GDF9 in the etiology of these conditions. We sought to determine how these mutations alter the biological activity of hGDF9.

Follicle development, endocrine profiles and ovulation rate in adult Merino ewes: effects of early nutrition (pre- and post-natal) and supplementation with lupin grain.

In adult ewes, we tested whether ovarian function, including the response to short-term supplementation, was affected by the nutrition of their mothers during the pre-/post-natal period. A 2×2 factorial design was used with nutrition in early life (low or high) and a 6-day supplement (with or without) as factors. All ewes received three prostaglandin (PG) injections 7 days apart, and the supplement (lupin grain) was fed for 6 days from 2 days after the second until the third PG injection.

Effects of immunization against androstenedione or bone morphogenetic protein 15 (BMP15) on reproductive performance in sheep.

Partial neutralization of bone morphogenetic protein 15 (BMP15) bioactivity by immunization is known to increase ovulation rate in sheep. However, it remains uncertain whether BMP15 vaccination would be a suitable procedure for increasing lambing rate. The aim of this study was to compare the efficacy of a BMP15 vaccination treatment on lamb production to that of commercially-available androstenedione-based vaccines that are used for this purpose.

Ranking and selection of MII oocytes in human ICSI cycles using gene expression levels from associated cumulus cells.

Study Question: Can the ranked expression levels of a cohort of cumulus cell (CC) genes be used to select MII oocytes with a potential for blastocyst development and live birth?

Summary Answer: A ranking method containing four (HAS2, FSHR, VCAN, PR) of the eight genes evaluated in this study for identifying good quality MII oocytes provides a significantly better outcome compared with random selection and is equally as good as using all oocytes for ICSI.

What Is Known Already: Recent evidence has identified a number of candidate genes in CC that have the potential to serve as markers of oocyte quality; however, a reliable method for selecting MII oocytes with blastocyst and live birth potential remains a challenge.

Study Design, Size, Duration: A group of 25 patients (<38 years old) underwent rFSH-stimulated ICSI treatment with single embryo replacement (SET).

Using sheep lines with mutations in single genes to better understand ovarian function.

Livestock populations have been subjected to strong selection pressure to improve reproductive success, and this has led to the identification of lines of animals with increased fecundity. These animals provide a rich biological resource for discovery of genes and regulatory mechanisms that underpin improved reproductive success. To date, three genes, all related to the transforming growth factor β pathway, have been identified as having mutations that lead to alterations in ovulation in sheep.

An earlier rise in systemic progesterone and increased progesterone in the uterine vein during early pregnancy are associated with enhanced embryonic survival in the ewe.

Improved livestock production efficiency through greater embryonic survival (ES) is of economic and animal welfare benefit. Physiological characterization of animals that are extreme outliers for ES provides a valuable opportunity to identify a naturally occurring mechanism by which this trait may be enhanced. The objective was to determine the likely cause for the lifetime history of enhanced or reduced ES in a line of ewes selected for high fecundity.

The fate of granulosa cells following premature oocyte loss and the development of ovarian cancers.

This review examines the importance of the epithelial origin of granulosa cells and their possible contribution to the development of ovarian cancers in three animal models. We hypothesise that undifferentiated granulosa cells, devoid of their germ cell regulator, retain their embryonic plasticity and may give rise to ovarian cancers of epithelial origin. Dazl-KO and FancD2-KO mice and BMP15-KO sheep are animal models in which germ cells or oocytes are lost at specific stages of follicular formation or growth, leaving behind clusters of residual, but healthy somatic cells.

Effects of species differences on oocyte regulation of granulosa cell function.

The aims were to investigate whether oocyte-secreted growth factors from a high (i.e. rat) and low (i.

Booroola BMPR1B mutation alters early follicular development and oocyte ultrastructure in sheep.

Booroola ewes homozygous (BB) for a mutation in the bone morphogenetic protein receptor-1b (BMPR1B) gene exhibit higher ovulation rates, have larger diameter oocytes at earlier stages of follicular development (i.e. Type 3) and smaller diameter follicles at ovulation than wild-type (++) sheep.