Mammalian oocyte therapies

In assisted human reproduction, the cytoplasm of oocytes recovered from follicles is often abnormal. Its lower quality, especially in older patients, may be responsible for certain chromosomal abnormalities or developmental arrest. Thus, the deficiency of some vital molecules, which are necessary for oocyte maturation, can be the cause of infertility in women. Moreover, mutated mitochondrial DNA (mtDNA) that is located in the oocyte cytoplasm might be transmitted to offspring. With the advance of new micromanipulation techniques like the oocyte nucleus replacement or cytoplasmic transfer, some of these abnormalities could be theoretically eliminated. In this review, we briefly discuss some of these approaches and their potential use in assisted human reproduction.     

Improving delivery and offspring viability of in vitro-produced and cloned sheep embryos

Recently developed, assisted reproductive technologies (e.g., in vitro embryo production and nuclear transfer) have encountered perinatal morbidity/mortality of the offspring produced, which are likely to hinder the application of these techniques. Consequently we have sought to develop a system of hormonal stimulation that will ensure the delivery of offspring more prepared for extrauterine life. Here we examine deliveries outcome in sheep carrying in vitro-produced and nuclear transfer (NT) embryos in comparison to artificially inseminated and naturally mated control ewes. All groups (excluding NT, which received one treatment) were subjected to one of two hormonal treatments for induction of delivery, whereas the third part of each group was left without any treatment. The first (commonly used for naturally mated ewes) dexamethasone treatment did not solve a majority of parturition disturbances, and actually the number of deliveries necessitating assistance was reduced (P < 0.05) by this treatment in the control group. On the other hand, combined estradiol plus betamethasone stimulation (E + B) solved a majority of complications regarding delivery performance such as lack of the preparation of the mammary gland, low myometrial contractility, insufficient cervical ripening, and impaired maternal behavior. Moreover, substantial reduction of neonatal mortality was observed following the combined treatment. In conclusion, the E + B induction of delivery overcame the majority of physiological and behavioral intrapartum failures of sheep foster mothers and increased the survival of offspring, and thus can be recommended as a safe method for inducing delivery in foster mothers carrying in vitro-generated embryos.     

Inhibition of Methyltransferase Setd7 Allows the In Vitro Expansion of Myogenic Stem Cells with Improved Therapeutic Potential

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Chromosomal Location of Genes Encoding Barley (1-->3, 1-->4)-beta-Glucan 4-Glucanohydrolases

Preparations of DNA from wheat (Triticum aestivum, cv Chinese Spring), barley (Hordeum vulgare, cv Betzes) and six euplasmic wheat-barley addition lines were digested to completion with restriction endonucleases and the products probed by Southern blot analysis using a cDNA-encoding barley (1→3, 1→4)-β-glucanase isoenzyme II. It is shown that one of the barley (1→3, 1→4)-β-glucanase genes is located on chromosome 1.     

In vitro separation and development of sheep blastomeres

Four cell embryos collected by laparatomy from Sardinian breed ewes superovulated with FSH-p (16 mg Sigma), were divested of their zonae pellucidae (ZP) by micromanipulation or chemical methods (pronase 0.5%, tyrode pH 2.2). The blastomeres were separated by pipetting using a flame polished pasteur pipette in a Ca free medium (PBS. Sigma) and were inserted into previously evacuated Z.P. using a Leitz micromanipulator. The Z.P. were removed either mechanically or with acid tyrode; pronase was unable to digest them after incubation at 30 degrees C for 120 minutes. The single blastomeres were cocultured on a monolayer of ovine oviductal epithelial cells in TCM 199 + 10 FCS at 38 degrees C in 5% CO2 for 60 hours. No developments were observed in blastomeres obtained by acid digestion of the ZP while 50% of the other blastomeres continued their development until the 16 cell stages. Our results suggest that coculture with oviductal epithelial cell monolayers can support in vitro development of single ovine blastomeres.     

ATGs help MHC class II,but inhibit MHC class I antigen presentation

We have recently shown that the LC3/Atg8 lipidation machinery of macroautophagy is involved in the internalization of MHC class I molecules. Decreased internalization in the absence of ATG5 or ATG7 leads to MHC class I surface stabilization on dendritic cells and macrophages, resulting in elevated CD8⁺ T cell responses during viral infections and improved immune control. Here, we discuss how the autophagic machinery supports MHC class II restricted antigen presentation, while compromising MHC class I presentation via internalization and degradation.