Heat transfer for Marangoni convection over a vapor-liquid interface due to an imposed temperature gradient

A similarity analysis for Marangoni convection induced flow over a vapor-liquid interface due to an imposed temperature gradient was carried out. The analysis assumes that the surface tension varies linearly with temperature but the temperature variation is a power law function of the location. The similarity solutions are presented numerically and the associated transfer characteristics are discussed.

Short telomeres impede germ cell specification by upregulating MAPK and TGFβsignaling

Functional telomeres protect chromosome ends and play important roles in stem cell maintenance and differentiation. Short telomeres negatively impact germ cell development and can contribute to age-associated infertility. Moreover, telomere syndrome resulting from mutations of telomerase or telomere-associated genes exhibits short telomeres and reduced fertility. It remains elusive whether and how telomere lengths affect germ cell specification. We report that functional telomere is required for the coordinated germ cell and somatic cell fate decisions. Using telomerase gene Terc deficient mice as a model, we show that short telomeres restrain germ cell specification of epiblast cells but promote differentiation towards somatic lineage. Short telomeres increase chromatin accessibility to elevate TGFβ and MAPK/ERK signaling for somatic cell differentiation. Notably,elevated Fst expression in TGFβ pathway represses the BMP4-pSmad signaling pathway, thus reducing germ cell formation. Reelongation of telomeres by targeted knock-in of Terc restores normal chromatin accessibility to suppress TGFβ and MAPK signaling, thereby facilitating germ cell formation. Taken together, our data reveal that functional telomeres are required for germ cell specification by repressing TGFβ and MAPK signaling.

Generation of developmentally competent oocytes and fertile mice from parthenogenetic embryonic stem cells

Parthenogenetic embryos,created by activation and diploidization of oocytes,arrest at mid-gestation for defective paternal imprints,which impair placental development.Also,viable offspring has not been obtained without genetic manipulation from parthenogenetic embryonic stem cells(pESCs)derived from parthenogenetic embryos,presumably attributable to their aberrant imprinting.We show that an unlimited number of oocytes can be derived from pESCs and produce healthy offspring.Moreover,normal expression of imprinted genes is found in the germ cells and the mice.pESCs exhibited imprinting consistent with exclusively maternal lineage,and higher X-chromosome activation compared to female ESCs derived from the same mouse genetic background.pESCs differentiated into primordial germ cell-like cells(PGCLCs)and formed oocytes following in vivo transplantation into kidney capsule that produced fertile pups and reconstituted ovarian endocrine function.The transcriptome and methylation of imprinted and X-linked genes in pESC-PGCLCs closely resembled those of in vivo produced PGCs,consistent with efficient reprogramming of methylation and genomic imprinting.These results demonstrate that amplification of germ cells through parthenogenesis faithfully maintains maternal imprinting,offering a promising route for deriving functional oocytes and having potential in rebuilding ovarian endocrine function.

Characterization of oogonia stem cells in mice by Fragilis

Dear Editor,Identification of oogonia stem cells would have great potentials in infertility treatment and fertility preservation.Here we tested whether Fragilis/lfitm3 can identify oogonia stem cells in fetal mouse ovaries and their molecular features,if it can,and whether the oogonia stem cells marked by Fragilis can be found in the postnatal ovaries.

Correction to:Characterization of oogonia stem cells in mice by Fragilis

Figure 2.Neo-meiosis and functional test of oocytes developed from Fragilis*cells.(A)Immunofluorescenee of SCP1(red)and SCP3(green,appear as yellowish by merge with SCP1)showing pachytene spread of E12.5 Fragilis*cells obtained from aggregates with fetal E12.5 somatic cells 6 days following transplantation,compared with those of E17.5 ovaries.Right panel,Percentage of synaptonemal complex elements based on count of spread at pachytene(n-22).Scale bar=5 pm.(B)Representative immunofluorescence of MLH1 foci at pachytene stage by co-immunostaining of SCP3(red)and MLH1(green).Right panel,Statistics of MLH1 foci represents 20 spread per each group.

Correction to: Characterization of oogonia stem cells in mice by Fragilis

Correction to:Protein Cell 2019,10(11):825831 htps://oi.org/0/.007/13238-019-0106545-0 In the original publiq|htps://doi.Org/10.1007/sI P 1D,Y-axis is incorrectly publisheb.Thooonoot aooninrgorrodld be read as Fragilis+/SSEA1+and the correct Figure 1 is provided in this correction.