No abstract

Gastrulation is a key event in embryonic development when the germ layers are specified and the basic animal body plan is established. The complexities of primate gastrulation remain a mystery because of the difficulties in accessing primate embryos at this stage. Here, we report the establishment of an in vitro culture (IVC) system that supports the continuous development of cynomolgus monkey blastocysts beyond early gastrulation up to 20 days after fertilization. The IVC embryos highly recapitulated the key events of in vivo early postimplantation development, including segregation of the epiblast and hypoblast, formation of the amniotic and yolk sac cavities, appearance of the primordial germ cells, and establishment of the anterior-posterior axis. Single-cell RNA-sequencing analyses of the IVC embryos provide information about lineage specification during primate early postimplantation development. This system provides a platform with which to explore the characteristics and mechanisms of early postimplantation embryogenesis in primates with possible conservation of cell movements and lineages in human embryogenesis.

During white-light exposure, the region outside of the hologram polymerized to form a random-phase segregated morphology referred to as the floodlit region. Film thickness was controlled by the addition of 10 lm diameter glass rods to the pre-polymer syrup. The diffraction efficiency of the grating was determined through the ratio of the intensity of diffracted light to incident light using a He-Ne (632 nm) laser. SEM images were collected with a Hitachi 900S operating at 1 keV. The PM597 was excited with the doubled output (532 nm) of a Nd:YAG that had a repetition rate of 10 Hz and pulse duration of 5-8 ns. Photoluminescence (PL) was collected perpendicular to the cell with an Ocean Optics CCD/spectrometer that had a resolution of 1.9 nm.

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A comprehensive set of transition probabilities and radiative lifetimes of Rydberg states of alkali atoms (for Na, K, Cs, n 30; and for Rb, n 6 50) is obtained by using a simple, exactly solvable potential model for atoms. The results agree well with the available experimental values and other theoretical ones. Scaling relations for evaluating transition probabilities and lifetimes of high Rydberg states are also discussed. The well known (n*)-' scaling law of the transition probabilities A,,,,. with n'= n >> 1 is generally valid; however, we also find deviations from this law for some d-, p and f-* d transitions for Rb. A third-power polynomial is found to be better than the currently used exponential scaling law in predicting the lifetimes of even higher excited states.

Preimplantation embryogenesis encompasses several critical events including genome reprogramming, zygotic genome activation (ZGA), and cell-fate commitment. The molecular basis of these processes remains obscure in primates in which there is a high rate of embryo wastage. Thus, understanding the factors involved in genome reprogramming and ZGA might help reproductive success during this susceptible period of early development and generate induced pluripotent stem cells with greater efficiency. Moreover, explaining the molecular basis responsible for embryo wastage in primates will greatly expand our knowledge of species evolution. By using RNA-seq in single and pooled oocytes and embryos, we defined the transcriptome throughout preimplantation development in rhesus monkey. In comparison to archival human and mouse data, we found that the transcriptome dynamics of monkey oocytes and embryos were very similar to those of human but very different from those of mouse. We identified several classes of maternal and zygotic genes, whose expression peaks were highly correlated with the time frames of genome reprogramming, ZGA, and cell-fate commitment, respectively. Importantly, comparison of the ZGA-related network modules among the three species revealed less robust surveillance of genomic instability in primate oocytes and embryos than in rodents, particularly in the pathways of DNA damage signaling and homology-directed DNA double-strand break repair. This study highlights the utility of monkey models to better understand the molecular basis for genome reprogramming, ZGA, and genomic stability surveillance in human early embryogenesis and may provide insights for improved homologous recombination-mediated gene editing in monkey.

The paper described here concerns a challenge of general interest for producing a novel structure of a polymer aggregate, the achievement of nanowires with controlled diameters. We provide a strategy for fabricating a supramolecular polymer, in which ordered polydiacetylene nanowires can be obtained by associated self-polymerization and self-assembly processes. The polymer nanowire film shows excellent field emission properties with the turn-on field of 8.2 V/mum at 10 muA/cm2 and the maximum current density of 5 mA/cm2 at an applied field of 15 V/mum.

4-Methyl-2-nitroacetanilide (1) crystallizes in white (1W), amber (1A), and yellow (1Y) modifications. The isomorphic molecules 4-chloro-2-nitroacetanilide (2) and 2-nitro-4-trifluoromethylacetanilide (3) were synthesized, and their effects on the crystallization of 1 were studied. The percentages of an additive incorporated into the 1W, 1A, and 1Y crystal lattices were determined by HPLC. Compound 2 is incorporated as a solid solution in 1A up to levels of 30% (w/w), whereas the incorporation efficiency of 3 is much lower at the same doping level. From these results it can be assumed that 2 causes less disruption to the host lattices than does 3. At the same doping level of an additive, 1A incorporates the additive at a greater level than 1W or 1Y. As the incorporation level of an additive increases, both the solution and solid-state transformation rate from 1A to either 1W or 1Y decreases. Structural comparison of the 1W, 1A, and 1Y crystal lattices indicates that the additives may be least disruptive to the 1A lattice, therefore explaining the greater incorporation efficiency of an additive in 1A.