Prophase I arrest and progression to metaphase I in mouse oocytes are controlled by Emi1-dependent regulation of APC(Cdh1).

Mammalian oocytes are arrested in prophase of the first meiotic division. Progression into the first meiotic division is driven by an increase in the activity of maturation-promoting factor (MPF). In mouse oocytes, we find that early mitotic inhibitor 1 (Emi1), an inhibitor of the anaphase-promoting complex (APC) that is responsible for cyclin B destruction and inactivation of MPF, is present at prophase I and undergoes Skp1-Cul1-F-box/betaTrCP-mediated destruction immediately after germinal vesicle breakdown (GVBD). Exogenous Emi1 or the inhibition of Emi1 destruction in prophase-arrested oocytes leads to a stabilization of cyclin B1-GFP that is sufficient to trigger GVBD. In contrast, the depletion of Emi1 using morpholino oligonucleotides increases cyclin B1-GFP destruction, resulting in an attenuation of MPF activation and a delay of entry into the first meiotic division. Finally, we show that Emi1-dependent effects on meiosis I require the presence of Cdh1. These observations reveal a novel mechanism for the control of entry into the first meiotic division: an Emi1-dependent inhibition of APC(Cdh1).

Assessing a pilot co-operative-based workshop-subsidy model toward improving small-scale chicken production in peri-urban Nepal.

Farmers in Nepal face many of the same global challenges associated with initiating and scaling poultry husbandry as many other developing countries. These include access to innovative approaches in finance, credit, coop design, marketing, and sales. As with most low-income countries, Nepalese poultry farmers also lack adequate training in poultry husbandry including biosecurity. In this paper, we describe a collaborative workshop-subsidy approach to addressing these challenges conducted by a partnership with the UC Davis School of Veterinary Medicine, the College of Engineering, the School of Education, and a farming co-operative based in the semi-rural area of Bhaktapur, Nepal. The program included two workshops covering aspects of poultry rearing including coop construction, chick rearing, biosecurity, and husbandry. Both workshops were a combination of lectures and hands-on learning. Following completion of the workshops, each farmer received subsidized materials for coop construction and poultry rearing. The co-operative provided training facilities and a market for selling eggs. Despite an outbreak of Highly Pathogenic Avian Influenza (HPAI), which affected the scale of program implementation, our results suggest that the workshop subsidy collaborative approach can be successful in reducing market entry barriers. Our 6-mo post-workshop survey showed that two-thirds of the workshop participants ultimately built their own coop and raised chicks. Half of these participants reported market available egg production and a doubling of egg consumption at home.

A Broken Heart After Witnessing a Dying Heart: A Case of Takotsubo Cardiomyopathy.

Takotsubo cardiomyopathy is a form of non-ischemic cardiomyopathy characterized by transient systolic dysfunction. The prevalence of Takotsubo cardiomyopathy has been estimated to be about 2% overall but about 10% amongst women presenting with clinical manifestations of acute coronary syndrome. The overall mechanism of the disease still remains unclear. However, treatment of Takotsubo cardiomyopathy appears to be similar to congestive heart failure (CHF) medical management. This case highlights the classic presentation exhibited very similar to acute coronary syndrome and diagnostic criteria for Takotsubo (stress-induced) cardiomyopathy.

Luteinizing hormone-dependent activation of the epidermal growth factor network is essential for ovulation.

In the preovulatory ovarian follicle, mammalian oocytes are maintained in prophase meiotic arrest until the luteinizing hormone (LH) surge induces reentry into the first meiotic division. Dramatic changes in the somatic cells surrounding the oocytes and in the follicular wall are also induced by LH and are necessary for ovulation. Here, we provide genetic evidence that LH-dependent transactivation of the epidermal growth factor receptor (EGFR) is indispensable for oocyte reentry into the meiotic cell cycle, for the synthesis of the extracellular matrix surrounding the oocyte that causes cumulus expansion, and for follicle rupture in vivo. Mice deficient in either amphiregulin or epiregulin, two EGFR ligands, display delayed or reduced oocyte maturation and cumulus expansion. In compound-mutant mice in which loss of one EGFR ligand is associated with decreased signaling from a hypomorphic allele of the EGFR, LH no longer signals oocyte meiotic resumption. Moreover, induction of genes involved in cumulus expansion and follicle rupture is compromised in these mice, resulting in impaired ovulation. Thus, these studies demonstrate that LH induction of epidermal growth factor-like growth factors and EGFR transactivation are essential for the regulation of a critical physiological process such as ovulation and provide new strategies for manipulation of fertility.

Synthesis of a low band gap polymer and its application in highly efficient polymer solar cells.

HOMO level of the PBDTTT-based polymer was successfully reduced by introducing an ketone group in place of the ester group. The average PCE of the PBDTTT-based devices reached 6.3% with a champion PCE result of 6.58%. Due to its highly efficient photovoltaic performance and more feasible synthesis approach, PBDTTT-C has the potential to be successfully applied in the large-scale manufacturing of polymer solar cells.

Wee1B is an oocyte-specific kinase involved in the control of meiotic arrest in the mouse.

In most species, the meiotic cell cycle is arrested at the transition between prophase and metaphase through unclear somatic signals. Activation of the Cdc2-kinase component of maturation promoting factor (MPF) triggers germinal vesicle breakdown after the luteinizing hormone (LH) surge and reentry into the meiotic cell cycle. Although high levels of cAMP and activation of protein kinase A (PKA) play a critical role in maintaining an inactive Cdc2, the steps downstream of PKA in the oocyte remain unknown. Using a small-pool expression-screening strategy, we have isolated several putative PKA substrates from a mouse oocyte cDNA library. One of these clones encodes a Wee1-like kinase that prevents progesterone-induced oocyte maturation when expressed in Xenopus oocytes. Unlike the widely expressed Wee1 and Myt1, mWee1B mRNA and its protein are expressed only in oocytes, and mRNA downregulation by RNAi injection in vitro or transgenic overexpression of RNAi in vivo causes a leaky meiotic arrest. Ser15 residue of mWee1B is the major PKA phosphorylation site in vitro, and the inhibitory effects of the kinase are enhanced when this residue is phosphorylated. Thus, mWee1B is a key MPF inhibitory kinase in mouse oocytes, functions downstream of PKA, and is required for maintaining meiotic arrest.

Intraovarian tumor necrosis factor-related weak inducer of apoptosis/fibroblast growth factor-inducible-14 ligand-receptor system limits ovarian preovulatory follicles from excessive luteinization.

In addition to gonadotropins, many ovarian paracrine factors are crucial for optimal follicle rupture, oocyte maturation, and luteinization. Based on DNA microarray analyses, we found that transcripts for the fibroblast growth factor-inducible-14 (Fn14) receptor are increased after LH/human chorionic gonadotropin (hCG) treatment of gonadotropin-primed immature mice or rats. Fn14 is the cognate receptor for TNF-related weak inducer of apoptosis (TWEAK), a TNF superfamily member. TWEAK transcripts also were detected in the ovary; however, their levels were not regulated by gonadotropins. In situ hybridization analyses indicated that the Fn14 receptor is expressed in the granulosa and cumulus cells of preovulatory follicles and, to a lesser extent, in theca cells. In contrast, in situ hybridization analyses revealed that TWEAK is primarily expressed in theca cells. In cultured granulosa cells pretreated with hCG to induce Fn14 receptor expression, treatment with TWEAK suppressed progesterone synthesis without accompanying changes in cAMP production. Furthermore, intrabursal injection of TWEAK suppressed ovarian progesterone content in gonadotropin-primed rats. In contrast, preovulatory follicles cultured in the presence of the Fn14 decoy, a recombinant protein containing the ligand-binding domain of Fn14, led to increases in progesterone production, presumably by antagonizing the actions of endogenous TWEAK. Likewise, ip injection of the Fn14 decoy enhanced serum progesterone levels with accompanying increases in transcript levels for several key steroidogenic enzymes. The present findings demonstrate a suppressive role of the TWEAK/Fn14 signaling system in the ovary. Following gonadotropin induction of ovulation, Fn14 is induced and could protect preovulatory follicles from excessive luteinization.

Time-dependent effects of pre-aging polymer films in cell culture medium on cell adhesion and spreading.

We have tested the hypothesis that cell adhesion and spreading on polymer films are influenced by the amount of time that the polymer films are pre-aged in cell culture medium. Cell adhesion and spreading were assessed after a 6-h culture on poly(D,L-lactic acid) (PDLLA) films that had been pre-aged in cell culture medium for 30 min, 1, 3 or 7 d. Cell adhesion and spread area were enhanced as the duration of pre-aging PDLLA films in cell culture medium was increased. Materials characterization showed that the hydrophobicity and surface morphology of the PDLLA films changed with increasing length of pre-aging time. These results suggest that cell adhesion and spreading are sensitive to the time-dependent changes in PDLLA hydrophobicity and surface morphology that occur during exposure of the polymer to cell medium for different lengths of time. These results demonstrate that cell response to a degradable, biomedical polymer can change as a function of the amount of time that the polymer is exposed to physiological medium.

The spectrum of Trp- mutants isolated as 5-fluoroanthranilate-resistant clones in Saccharomyces bayanus, S. mikatae and S. paradoxus.

5-Fluoroanthranilic acid (FAA)-resistant mutants were selected in homothallic diploids of three Saccharomyces species, taking care to isolate mutants of independent origin. Mutations were assigned to complementation groups by interspecific complementation with S. cerevisiae tester strains. In all three species, trp3, trp4 and trp5 mutants were recovered. trp1 mutants were also recovered if the selection was imposed on a haploid strain. Thus, FAA selection may be more generally applicable than was previously described.

The G-protein-coupled receptors GPR3 and GPR12 are involved in cAMP signaling and maintenance of meiotic arrest in rodent oocytes.

In mammalian and amphibian oocytes, the meiotic arrest at the G2/M transition is dependent on cAMP regulation. Because genetic inactivation of a phosphodiesterase expressed in oocytes prevents reentry into the cell cycle, suggesting autonomous cAMP synthesis, we investigated the presence and properties of the G-protein-coupled receptors (GPCRs) in rodent oocytes. The pattern of expression was defined using three independent strategies, including microarray analysis of GV oocyte mRNAs, EST database scanning, and RT-PCR amplification with degenerated primers against transmembrane regions conserved in the GPCR superfamily. Clustering of the GPCR mRNAs from rat and mouse oocytes indicated the expression of the closely related Gpr3, Gpr12, and Edg3, which recognize sphingosine and its metabolites as ligands. Expression of these mRNAs was confirmed by RT-PCR with specific primers as well as by in situ hybridization. That these receptors are involved in the control of cAMP levels in oocytes was indicated by the finding that expression of the mRNA for Gpr3 and Gpr12 is downregulated in Pde3a-deficient oocytes, which have a chronic elevation of cAMP levels. Expression of GPR3 or GPR12 in Xenopus laevis oocytes prevented progesterone-induced meiotic maturation, whereas expression of FSHR had no effect. A block in spontaneous oocyte maturation was also induced when Gpr3 or Gpr12 mRNA was injected into mouse oocytes. Downregulation of GPR3 and GPR12 caused meiotic resumption in mouse and rat oocytes, respectively. However, ablation of the Gpr12 gene in the mouse did not cause a leaky meiotic arrest, suggesting compensation by Gpr3. Incubation of mouse oocytes with the GPR3/12 ligands SPC and S1P delayed spontaneous oocyte maturation. We propose that the cAMP levels required for maintaining meiotic arrest in mouse and rat oocytes are dependent on the expression of Gpr3 and/or Gpr12.