29 research outputs found
Generation of Genetically Modified Mice by Oocyte Injection of Androgenetic Haploid Embryonic Stem Cells
SummaryHaploid cells are amenable for genetic analysis. Recent success in the derivation of mouse haploid embryonic stem cells (haESCs) via parthenogenesis has enabled genetic screening in mammalian cells. However, successful generation of live animals from these haESCs, which is needed to extend the genetic analysis to the organism level, has not been achieved. Here, we report the derivation of haESCs from androgenetic blastocysts. These cells, designated as AG-haESCs, partially maintain paternal imprints, express classical ESC pluripotency markers, and contribute to various tissues, including the germline, upon injection into diploid blastocysts. Strikingly, live mice can be obtained upon injection of AG-haESCs into MII oocytes, and these mice bear haESC-carried genetic traits and develop into fertile adults. Furthermore, gene targeting via homologous recombination is feasible in the AG-haESCs. Our results demonstrate that AG-haESCs can be used as a genetically tractable fertilization agent for the production of live animals via injection into oocytes.PaperCli
Transient exposure to miR-203 expands the differentiation capacity of pluripotent stem cells
Full differentiation potential along with selfârenewal capacity is a major property of pluripotent stem cells (PSCs). However, the differentiation capacity frequently decreases during expansion of PSCs in vitro . We show here that transient exposure to a single microRNA, expressed at early stages during normal development, improves the differentiation capacity of alreadyâestablished murine and human PSCs. Short exposure to miRâ203 in PSCs (mi PSCs) induces a transient expression of 2C markers that later results in expanded differentiation potency to multiple lineages, as well as improved efficiency in tetraploid complementation and humanâmouse interspecies chimerism assays. Mechanistically, these effects are at least partially mediated by direct repression of de novo DNA methyltransferases Dnmt3a and Dnmt3b, leading to transient and reversible erasure of DNA methylation. These data support the use of transient exposure to miRâ203 as a versatile method to reset the epigenetic memory in PSCs, and improve their effectiveness in regenerative medicine
Parthenogenetic haploid embryonic stem cells efficiently support mouse generation by oocyte injection
Engineering of glycerol utilization in Gluconobacter oxydans 621H for biocatalyst preparation in a low-cost way
Abstract Background Whole cells of Gluconobacter oxydans are widely used in various biocatalytic processes. Sorbitol at high concentrations is commonly used in complex media to prepare biocatalysts. Exploiting an alternative process for preparation of biocatalysts with low cost substrates is of importance for industrial applications. Results G. oxydans 621H was confirmed to have the ability to grow in mineral salts medium with glycerol, an inevitable waste generated from industry of biofuels, as the sole carbon source. Based on the glycerol utilization mechanism elucidated in this study, the major polyol dehydrogenase (GOX0854) and the membrane-bound alcohol dehydrogenase (GOX1068) can competitively utilize glycerol but play no obvious roles in the biocatalyst preparation. Thus, the genes related to these two enzymes were deleted. Whole cells of G. oxydans âGOX1068âGOX0854 can be prepared from glycerol with a 2.4-fold higher biomass yield than that of G. oxydans 621H. Using whole cells of G. oxydans âGOX1068âGOX0854 as the biocatalyst, 61.6 g Lâ1 xylonate was produced from 58.4 g Lâ1 xylose at a yield of 1.05 g gâ1. Conclusion This process is an example of efficient preparation of whole cells of G. oxydans with reduced cost. Besides xylonate production from xylose, other biocatalytic processes might also be developed using whole cells of metabolic engineered G. oxydans prepared from glycerol
Long-term Exposure to Ambient Fine Particulate Pollution Induces Insulin Resistance and Mitochondrial Alteration in Adipose Tissue
Enzymatic Cascades for Efficient Biotransformation of Racemic Lactate Derived from Corn Steep Water
The
corn starch industry produces a large amount of corn steep
water, leading to high organic waste load. Lactate could be separated
from corn steep water at a low cost, which supports the value-added
utilization of corn steep water. However, the racemic characteristic
of lactate from corn steep water restricts the development of this
promising process. In this study, using d-lactate oxidase
(d-LOX) from <i>Gluconobacter oxydans</i>, l-lactate oxidase (l-LOX) from <i>Pediococcus</i> sp., pyruvate decarboxylase from <i>Zymomonas mobilis</i>, and catalase from bovine liver, we synthesized an <i>in vitro</i> enzymatic system, including different enzymatic cascades, for the
production of valuable platform chemicals from lactate separated from
the corn steep water. Pyruvate was produced as an important intermediate
and further converted into C2 (acetaldehyde) and C4 (acetoin) platform
chemicals at high yields using optimized concentrations of pyruvate
decarboxylase. The <i>in vitro</i> enzymatic system not
only provides a novel technology platform for the production of optical
lactate and lactate derivatives but also supports the sustainable
development of corn starch industry
Generation of human haploid embryonic stem cells from parthenogenetic embryos obtained by microsurgical removal of male pronucleus
Recommended from our members
Efficient derivation of stable primed pluripotent embryonic stem cells from bovine blastocysts
Embryonic stem cells (ESCs) are derived from the inner cell mass of preimplantation blastocysts. From agricultural and biomedical perspectives, the derivation of stable ESCs from domestic ungulates is important for genomic testing and selection, genome engineering, and modeling human diseases. Cattle are one of the most important domestic ungulates that are commonly used for food and bioreactors. To date, however, it remains a challenge to produce stable pluripotent bovine ESC lines. Employing a culture system containing fibroblast growth factor 2 and an inhibitor of the canonical Wnt-signaling pathway, we derived pluripotent bovine ESCs (bESCs) with stable morphology, transcriptome, karyotype, population-doubling time, pluripotency marker gene expression, and epigenetic features. Under this condition bESC lines were efficiently derived (100% in optimal conditions), were established quickly (3-4 wk), and were simple to propagate (by trypsin treatment). When used as donors for nuclear transfer, bESCs produced normal blastocyst rates, thereby opening the possibility for genomic selection, genome editing, and production of cattle with high genetic value