Mammalian follicles are constituted of a complex structure composed of several layers of granulosa cells surrounding the oocyte and of theca cells that reside beneath its basement membrane. During ...folliculogenesis, granulosa cells separate into two anatomically and functionally distinct sub-types; the mural cells lining the follicle wall and the oocyte-surrounding cumulus cells, i.e. those in intimate metabolic contact with the oocyte. The cumulus cells connecting with the oocyte have trans-zonal cytoplasmic projections which, penetrating the zona pellucida, form the cumulus-oocyte complex. The connections through gap junctions allow the transfer of small molecules between oocyte and cumulus cells, such as ions, metabolites, and amino acids necessary for oocyte growth, as well as small regulatory molecules that control oocyte development. The bi-directional communication between the oocyte and cumulus cells is crucial for the development and functions of both cell types.
Our current knowledge of the relationship between the oocyte and its surrounding cumulus cells continues to change as we gain a greater understanding of factors regulating oocyte development and folliculogenesis. This review will mainly focus on the reciprocal interaction between oocytes and cumulus cells during the latter stages of follicle development i.e. through antral development to periovulatory events including oocyte maturation, expansion, and degradation of the cumulus matrix.
•The Cumulus cells are a biological barrier between the oocyte and its surroundings.•Oocyte-cumulus cell communication is crucial for development of both cell types.•Cumulus cells antioxidants are responsible for the oocyte oxidative stress defense.•Oocyte-secreted factors are primarily responsible for cumulus expansion.
Interspecies blastocyst complementation enables organ-specific enrichment of xenogenic pluripotent stem cell (PSC) derivatives. Here, we establish a versatile blastocyst complementation platform ...based on CRISPR-Cas9-mediated zygote genome editing and show enrichment of rat PSC-derivatives in several tissues of gene-edited organogenesis-disabled mice. Besides gaining insights into species evolution, embryogenesis, and human disease, interspecies blastocyst complementation might allow human organ generation in animals whose organ size, anatomy, and physiology are closer to humans. To date, however, whether human PSCs (hPSCs) can contribute to chimera formation in non-rodent species remains unknown. We systematically evaluate the chimeric competency of several types of hPSCs using a more diversified clade of mammals, the ungulates. We find that naïve hPSCs robustly engraft in both pig and cattle pre-implantation blastocysts but show limited contribution to post-implantation pig embryos. Instead, an intermediate hPSC type exhibits higher degree of chimerism and is able to generate differentiated progenies in post-implantation pig embryos.
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•Naive rat PSCs robustly contribute to live rat-mouse chimeras•A versatile CRISPR-Cas9 mediated interspecies blastocyst complementation system•Naive rodent PSCs show no chimeric contribution to post-implantation pig embryos•Chimerism is observed with some human iPSCs in post-implantation pig embryos
Human pluripotent stem cells robustly engraft into both cattle and pig pre-implantation blastocysts, but show limited chimeric contribution to post-implantation pig embryos.
This study was designed to investigate the impact of vitrification on the transcriptome profile of blastocysts using a porcine (
) model and a microarray approach. Blastocysts were collected from ...weaned sows (
= 13). A total of 60 blastocysts were vitrified (treatment group). After warming, vitrified embryos were cultured in vitro for 24 h. Non-vitrified blastocysts (
= 40) were used as controls. After the in vitro culture period, the embryo viability was morphologically assessed. A total of 30 viable embryos per group (three pools of 10 from 4 different donors each) were subjected to gene expression analysis. A fold change cut-off of ±1.5 and a restrictive threshold at
-value < 0.05 were used to distinguish differentially expressed genes (DEGs). The survival rates of vitrified/warmed blastocysts were similar to those of the control (nearly 100%, n.s.). A total of 205 (112 upregulated and 93 downregulated) were identified in the vitrified blastocysts compared to the control group. The vitrification/warming impact was moderate, and it was mainly related to the pathways of cell cycle, cellular senescence, gap junction, and signaling for TFGβ, p53, Fox, and MAPK. In conclusion, vitrification modified the transcriptome of in vivo-derived porcine blastocysts, resulting in minor gene expression changes.
Successful establishment of pregnancy includes the achievement of a state of immune tolerance toward the embryos (and placenta), where the well‐coordinated maternal immune system is capable of ...recognizing conceptus antigens while maintaining maternal defense against pathogens. In physiological pregnancies, following natural mating or artificial insemination (AI), the maternal immune system is exposed to the presence of hemi‐allogeneic embryos, that is, embryos containing maternal self‐antigens and foreign antigens from the paternal side. In this scenario, the hemi‐allogeneic embryo is recognized by the mother, but the immune system is locally modified to facilitate embryo implantation and pregnancy progression. Pig allogeneic pregnancies (with embryos containing both paternal and maternal material foreign to the recipient female), occur during embryo transfer (ET), with conspicuously high rates of embryonic death. Mortality mainly occurs during the peri‐attachment phase, suggesting that immune responses to allogeneic embryos are more complex and less efficient, hindering the conceptuses to survive to term. Reaching a similar maternal tolerance as in conventional breeding would render ET successful. The present review critically summarizes mechanisms of maternal immune recognition of pregnancy and factors associated with impaired maternal immune response to the presence of allogeneic embryos in the porcine species.
Shrinking Cities: Urban Challenges of Globalization MARTINEZ-FERNANDEZ, CRISTINA; AUDIRAC, IVONNE; FOL, SYLVIE ...
International journal of urban and regional research,
March 2012, Letnik:
36, Številka:
2
Journal Article
Recenzirano
Urban shrinkage is not a new phenomenon. It has been documented in a large literature analyzing the social and economic issues that have led to population flight, resulting, in the worse cases, in ...the eventual abandonment of blocks of housing and neighbourhoods. Analysis of urban shrinkage should take into account the new realization that this phenomenon is now global and multidimensional — but also little understood in all its manifestations. Thus, as the world's population increasingly becomes urban, orthodox views of urban decline need redefinition. The symposium includes articles from 10 urban analysts working on 30 cities around the globe. These analysts belong to the Shrinking Cities International Research Network (SCIRN), whose collaborative work aims to understand different types of city shrinkage and the role that different approaches, policies and strategies have played in the regeneration of these cities. In this way the symposium will inform both a rich diversity of analytical perspectives and country‐based studies of the challenges faced by shrinking cities. It will also disseminate SCIRN's research results from the last 3 years.
Résumé
La décroissance urbaine n'est pas un phénomène nouveau. De nombreux travaux ont analysé les problèmes sociaux et économiques conduisant au départ de populations et résultant dans les pires des cas à l'abandon d'îlots d'habitat et de quartiers entiers. Cependant, l'étude de la décroissance urbaine doit aujourd'hui tenir compte du constat récent selon lequel ce phénomène est désormais global et multidimensionnel, tout en restant peu appréhendé dans toutes ses composantes. Ainsi, alors que la population mondiale est de plus en plus urbaine, les conceptions classiques du déclin urbain méritent d'être réexaminées. Ce symposium inclut des articles de dix chercheurs travaillant sur trente villes à travers le monde. Ils appartiennent au Shrinking Cities International Research Netwok (SCIRN), dont le travail collectif a pour objectif d'analyser différents types de décroissance urbaine et le rôle que les multiples approches, politiques et stratégies ont joué dans la régénération des villes touchées par ce processus. Ce numéro s'appuie sur une diversité d'approches et sur l'étude de contextes urbains variés, ayant pour point commun d'être concernés par les enjeux de la décroissance urbaine. Il permet de diffuser les résultats des recherches menées au sein du SCIRN au cours des trois dernières années.
•Gastroduodenal quinoa protein digests showed potent in vitro anti-diabetic properties.•Peptides released during digestion could contribute on the observed effects.•Activity was mediated through ...DPP-IV, α-amylase, and α-glucosidase inhibition.•Three novel peptides derived from 11S seed storage globulin B were identified.
As diabetes is a major cause of mortality and morbidity in epidemic rates, continuous research is being done on development of foods with anti-diabetic activity. In this study, the influence of gastrointestinal digestion of quinoa protein to release peptides with anti-diabetic potential was investigated. Quinoa protein was subjected to an in vitro simulated gastrointestinal digestion and fractionated by ultrafiltration. Gastric and gastroduodenal digests and peptide fractions were evaluated for dipeptidyl peptidase IV (DPP-IV), α-amylase and α-glucosidase inhibitory activities. Peptides released during the duodenal phase showed the highest inhibitory effects. Three novel peptides derived from 11S seed storage globulin B were identified in the most active fraction by HPLC-MS/MS. These peptides showed ability to inhibit enzymes involved in incretin degradation and digestion of dietary carbohydrates. Therefore, quinoa proteins are promising ingredients of functional foods or nutraceutical applications for the control of diabetes.
Reducing hurdles to clinical trials without compromising the therapeutic promises of peptide candidates becomes an essential step in peptide-based drug design. Machine-learning models are ...cost-effective and time-saving strategies used to predict biological activities from primary sequences. Their limitations lie in the diversity of peptide sequences and biological information within these models. Additional outlier detection methods are needed to set the boundaries for reliable predictions; the applicability domain. Antimicrobial peptides (AMPs) constitute an extensive library of peptides offering promising avenues against antibiotic-resistant infections. Most AMPs present in clinical trials are administrated topically due to their hemolytic toxicity. Here we developed machine learning models and outlier detection methods that ensure robust predictions for the discovery of AMPs and the design of novel peptides with reduced hemolytic activity. Our best models, gradient boosting classifiers, predicted the hemolytic nature from any peptide sequence with 95-97% accuracy. Nearly 70% of AMPs were predicted as hemolytic peptides. Applying multivariate outlier detection models, we found that 273 AMPs (~ 9%) could not be predicted reliably. Our combined approach led to the discovery of 34 high-confidence non-hemolytic natural AMPs, the de novo design of 507 non-hemolytic peptides, and the guidelines for non-hemolytic peptide design.
•Germination effect on the nutritional benefits of germinated brown rice bread is determined.•Germination for 48h provides gluten free bread with nutritionally superior quality.•Breads with higher ...content of protein, lipids and bioactive compounds are obtained.•Breads also have increased antioxidant activity and reduced phytic acid content.•Germination reduces significantly the glycaemic index of rice based gluten free breads.
The effect of germination conditions on the nutritional benefits of germinated brown rice flour (GBR) bread has been determined. The proximate composition, phytic acid, in vitro protein digestibility and in vitro enzymatic hydrolysis of starch, glucose and starch content, as well as the most relevant bioactive compounds (GABA, γ-oryzanol and total phenolic compounds) and antioxidant activity of breads prepared with GBR at different germination conditions was determined. When comparing different germination times (0h, 12h, 24h and 48h), germination for 48h provides GBR bread with nutritionally superior quality on the basis of its higher content of protein, lipids and bioactive compounds (GABA and polyphenols), increased antioxidant activity and reduced phytic acid content and glycaemic index, although a slight decrease in in vitro protein digestibility was detected. Overall, germination seems to be a natural and sustainable way to improving the nutritional quality of gluten-free rice breads.
Spermatozoa need to conduct a series of biochemical changes termed capacitation in order to fertilize. In vivo, capacitation is sequentially achieved during sperm transport and interaction with the ...female genital tract, by mechanisms yet undisclosed in detail. However, when boar spermatozoa are stored in the tubal reservoir pre-ovulation, most appear to be in a non-capacitated state. This study aimed at deciphering the transcriptomics of capacitation-related genes in the pig pre-ovulatory oviduct, following the entry of semen or of sperm-free seminal plasma (SP). Ex-vivo samples of the utero-tubal junction (UTJ) and isthmus were examined with a microarray chip (GeneChip
Porcine Gene 1.0 ST Array, Thermo Fisher Scientific) followed by bioinformatics for enriched analysis of functional categories (GO terms) and restrictive statistics. The results confirmed that entry of semen or of relative amounts of sperm-free SP modifies gene expression of these segments, pre-ovulation. It further shows that enriched genes are differentially associated with pathways relating to sperm motility, acrosome reaction, single fertilization, and the regulation of signal transduction GO terms. In particular, the pre-ovulation oviduct stimulates the Catsper channels for sperm Ca
influx, with
and
genes being positive regulators while
and
genes appear to be inhibitors of the process. We postulate that the stimulation of
and
genes in the pre-ovulation sperm reservoir/adjacent isthmus, mediated by SP, act to prevent premature massive capacitation prior to ovulation.
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