Society for Reproductive Biology Founders' Lecture 2003.The making of an embryo: short-term goals and long-term implications.

2004 ◽  
Vol 16 (3) ◽  
pp. 325 ◽  
Author(s):  
Tom P. Fleming ◽  
Adrian Wilkins ◽  
Andrew Mears ◽  
Daniel J. Miller ◽  
Fay Thomas ◽  
...  

During early development, the eutherian mammalian embryo forms a blastocyst comprising an outer trophectoderm epithelium and enclosed inner cell mass (ICM). The short-term goal of blastocyst morphogenesis, including epithelial differentiation and segregation of the ICM, is mainly regulated autonomously and comprises a combination of temporally controlled gene expression, cell polarisation, differentiative cell divisions and cell–cell interactions. This aspect of blastocyst biogenesis is reviewed, focusing, in particular, on the maturation and role of cell adhesion systems. Early embryos are also sensitive to their environment, which can affect their developmental potential in diverse ways and may lead to long-term consequences relating to fetal or postnatal growth and physiology. Some current concepts of embryo–environment interactions, which may impact on future health, are also reviewed.

2021 ◽  
Author(s):  
Chuan Chen ◽  
Wenqiang Liu ◽  
Jiayin Guo ◽  
Yuanyuan Liu ◽  
Xuelian Liu ◽  
...  

AbstractN6-methyladenosine (m6A) on chromosome-associated regulatory RNAs (carRNAs), including repeat RNAs, plays important roles in tuning the chromatin state and transcription, but the intrinsic mechanism remains unclear. Here, we report that YTHDC1 plays indispensable roles in the self-renewal and differentiation potency of mouse embryonic stem cells (ESCs), which highly depends on the m6A-binding ability. Ythdc1 is required for sufficient rRNA synthesis and repression of the 2-cell (2C) transcriptional program in ESCs, which recapitulates the transcriptome regulation by the LINE1 scaffold. Detailed analyses revealed that YTHDC1 recognizes m6A on LINE1 RNAs in the nucleus and regulates the formation of the LINE1-NCL partnership and the chromatin recruitment of KAP1. Moreover, the establishment of H3K9me3 on 2C-related retrotransposons is interrupted in Ythdc1-depleted ESCs and inner cell mass (ICM) cells, which consequently increases the transcriptional activities. Our study reveals a role of m6A in regulating the RNA scaffold, providing a new model for the RNA-chromatin cross-talk.


2021 ◽  
Author(s):  
Hongling Zhang ◽  
Yuanyuan Li ◽  
Yongjian Ma ◽  
Chongping Lai ◽  
Qian Yu ◽  
...  

AbstractThe use of two inhibitors of Mek1/2 and Gsk3β (2i) promotes the generation of mouse diploid and haploid embryonic stem cells (ESCs) from the inner cell mass of biparental and uniparental blastocysts, respectively. However, a system enabling long-term maintenance of imprints in ESCs has proven challenging. Here, we report that the use of a two-step a2i (alternative two inhibitors of Src and Gsk3β, TSa2i) derivation/culture protocol results in the establishment of androgenetic haploid ESCs (AG-haESCs) with stable DNA methylation at paternal DMRs (differentially DNA methylated regions) up to passage 60 that can efficiently support generating mice upon oocyte injection. We also show coexistence of H3K9me3 marks and ZFP57 bindings with intact DMR methylations. Furthermore, we demonstrate that TSa2i-treated AG-haESCs are a heterogeneous cell population regarding paternal DMR methylation. Strikingly, AG-haESCs with late passages display increased paternal-DMR methylations and improved developmental potential compared to early-passage cells, in part through the enhanced proliferation of H19-DMR hypermethylated cells. Together, we establish AG-haESCs that can long-term maintain paternal imprints.


Author(s):  
Zubing Cao ◽  
Xu Tong ◽  
Huiqun Yin ◽  
Naru Zhou ◽  
Xiangdong Zhang ◽  
...  

Coactivator-associated arginine methyltransferase 1 (CARM1) is involved in both establishment of first pluripotent lineage and pluripotency maintenance of embryonic stem cells (ESCs) in mice. However, the histone substrates and role of CARM1 in early embryonic development remain largely unknown. Here, we show that CARM1 specifically catalyzes H3R26me2 to promote porcine blastocyst formation. The putative histone substrates of CARM1, including H3R2me2, H3R17me2, and H3R26me2, are present in pig early embryos. The changes of CARM1 mRNA during early embryogenesis parallel that of H3R26me2. Functional studies using a combinational approach of chemical inhibition and RNA interference (RNAi) showed that catalytic activity inhibition of CARM1 protein or knockdown (KD) of CARM1 mRNA did not alter the levels of both H3R2me2 and H3R17me2, but significantly reduced H3R26me2 levels in porcine embryos. Furthermore, CARM1 inhibition or KD did not affect embryo development to the 2-cell, 4-cell, 8-cell, and morula stages, but severely compromised blastocyst development. CARM1 knocked down embryos that developed to the blastocyst stage had fewer total cells, inner cell mass (ICM), and trophectoderm (TE) cells. Mechanistically, single embryo RNA-sequencing analysis revealed that CARM1 KD altered the transcriptome characterized by downregulation of key genes associated with Hippo and PI3K-AKT signaling pathways. Taken together, these results demonstrate that CARM1 specifically catalyzes H3R26me2 in porcine embryos and participates in blastocyst development.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.


1997 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Brian De Vries

This article introduces a volume devoted to the examination of later-life bereavement: an analysis of variation in cause, course, and consequence. Six articles address and represent this variation and comprise this volume: 1) Prigerson et al. present case histories of the traumatic grief of spouses; 2) Hays et al. highlight the bereavement experiences of siblings in contrast to those spouses and friends; 3) Moss et al. address the role of gender in middle-aged children's responses to parent death; 4) Bower focuses on the language adopted by these adult children in accepting the death of a parent; 5) de Vries et al. explore the long-term, longitudinal effects on the psychological and somatic functioning of parents following the death of an adult child; and 6) Fry presents the short-term and longitudinal reactions of grandparents to the death of a grandchild. A concluding article is offered by de Vries stressing both the unique and common features of these varied bereavement experiences touching on some of the empirical issues and suggesting potential implications and applications.


2021 ◽  
Vol 13 (9) ◽  
pp. 5024
Author(s):  
 Vítor Manuel de Sousa Gabriel ◽  
María Mar Miralles-Quirós ◽  
José Luis Miralles-Quirós

This paper analyses the links established between environmental indices and the oil price adopting a double perspective, long-term and short-term relationships. For that purpose, we employ the Bounds Test and bivariate conditional heteroscedasticity models. In the long run, the pattern of behaviour of environmental indices clearly differed from that of the oil prices, and it was not possible to identify cointegrating vectors. In the short-term, it was possible to conclude that, in contemporaneous terms, the variables studied tended to follow similar paths. When the lag of the oil price variable was considered, the impacts produced on the stock market sectors were partially of a negative nature, which allows us to suppose that this variable plays the role of a risk factor for environmental investment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viet Cao ◽  
Ghinwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep

AbstractMetallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 days. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.


1992 ◽  
Vol 46 (1) ◽  
pp. 225-264 ◽  
Author(s):  
Raymond F. Hopkins

The principles and norms adopted by the regime governing food aid in the 1950s have changed substantially during the subsequent three decades. Explaining the changes necessarily includes analyzing the efforts of an international epistemic community consisting of economic development specialists, agricultural economists, and administrators of food aid. According to the initial regime principles, food aid should be provided from donors' own surplus stocks, should supplement the usual commercial food imports in recipient countries, should be given under short-term commitments sensitive to the political and economic goals of donors, and should directly feed hungry people. As a result of following these principles, the epistemic community and other critics argued, food aid often had the adverse effects of reducing local production of food in recipient countries and exacerbating rather than alleviating hunger. The epistemic community (1) developed and proposed ideas for more efficiently supplying food aid and avoiding “disincentive” effects and (2) pushed for reforms to make food aid serve as the basis for the recipients' economic development and to target it at addressing long-term food security problems. The ideas of the international epistemic community have increasingly received support from international organizations and the governments of donor and recipient nations. Most recently, they have led to revisions of the U.S. food aid program passed by Congress in October 1990 and signed into law two months later. As the analysis of food aid reform demonstrates, changes in the international regime have been incremental, rather than radical. Moreover, the locus for the change has shifted from an American-centered one in the 1950s to a more international one in recent decades.


2011 ◽  
Vol 35 (5) ◽  
pp. 613-628 ◽  
Author(s):  
Erik Gómez-Baggethun ◽  
Manuel Ruiz-Pérez

In the last decade a growing number of environmental scientists have advocated economic valuation of ecosystem services as a pragmatic short-term strategy to communicate the value of biodiversity in a language that reflects dominant political and economic views. This paper revisits the controversy on economic valuation of ecosystem services in the light of two aspects that are often neglected in ongoing debates. First, the role of the particular institutional setup in which environmental policy and governance is currently embedded in shaping valuation outcomes. Second, the broader economic and sociopolitical processes that have governed the expansion of pricing into previously non-marketed areas of the environment. Our analysis suggests that within the institutional setup and broader sociopolitical processes that have become prominent since the late 1980s economic valuation is likely to pave the way for the commodification of ecosystem services with potentially counterproductive effects in the long term for biodiversity conservation and equity of access to ecosystem services benefits.


Circulation ◽  
1993 ◽  
Vol 88 (3) ◽  
pp. 1205-1214 ◽  
Author(s):  
P Golino ◽  
G Ambrosio ◽  
M Ragni ◽  
I Pascucci ◽  
M Triggiani ◽  
...  

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