Evolutionary transition between invertebrates and vertebrates via methylation reprogramming in embryogenesis

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Xu, X., Li, G., Li, C., Zhang, J., Wang, Q., Simmons, D. K., Chen, X., Wijesena, N., Zhu, W., Wang, Z., Wang, Z., Ju, B., Ci, W., Lu, X., Yu, D., Wang, Q., Aluru, N., Oliveri, P., Zhang, Y. E., Martindale, M. Q., & Liu, J. Evolutionary transition between invertebrates and vertebrates via methylation reprogramming in embryogenesis. National Science Review, 6(5), (2019):993-1003, doi:10.1093/nsr/nwz064.Major evolutionary transitions are enigmas, and the most notable enigma is between invertebrates and vertebrates, with numerous spectacular innovations. To search for the molecular connections involved, we asked whether global epigenetic changes may offer a clue by surveying the inheritance and reprogramming of parental DNA methylation across metazoans. We focused on gametes and early embryos, where the methylomes are known to evolve divergently between fish and mammals. Here, we find that methylome reprogramming during embryogenesis occurs neither in pre-bilaterians such as cnidarians nor in protostomes such as insects, but clearly presents in deuterostomes such as echinoderms and invertebrate chordates, and then becomes more evident in vertebrates. Functional association analysis suggests that DNA methylation reprogramming is associated with development, reproduction and adaptive immunity for vertebrates, but not for invertebrates. Interestingly, the single HOX cluster of invertebrates maintains unmethylated status in all stages examined. In contrast, the multiple HOX clusters show dramatic dynamics of DNA methylation during vertebrate embryogenesis. Notably, the methylation dynamics of HOX clusters are associated with their spatiotemporal expression in mammals. Our study reveals that DNA methylation reprogramming has evolved dramatically during animal evolution, especially after the evolutionary transitions from invertebrates to vertebrates, and then to mammals.This work was supported by the National Key Research and Development Program of China (2018YFC1003303), the Strategic Priority Research Program of the CAS (XDB13040200), the National Natural Science Foundation of China (91519306, 31425015), the Youth Innovation Promotion Association of the CAS and the Key Research Program of Frontier Sciences, CAS (QYZDY-SSW-SMC016)

Effect of Children’s Support on Depression among Older Adults Living Alone or with a Spouse: A Comparative Analysis between Urban and Rural Areas of China

Against the backdrop of rapid urbanization and severe population aging, older adults living alone or with a spouse in China have become a special and vulnerable group that deserve more research attention. Based on a national sample of 3886 older adults (≥60 years old) living alone or with a spouse, we used multiple linear regression models to investigate the effect of children’s support on depression among older adults living alone or with a spouse in China. A comparative analysis was conducted to examine the differences between urban and rural areas. The results indicated that financial support from children was negatively correlated with depression among older adults living alone or with a spouse, especially in rural areas. Their children’s frequency of contact also significantly alleviated depression among non-cohabiting parents in rural areas, but not for the same types of parents living in urban areas. Compared with financial support, their children’s frequency of contact contributes more to decreasing depression among older adults living alone or with a spouse. The effect of their children’s support on depression is comparable to that of demographic characteristics, which are usually deemed as important factors in the psychological health of older adults. Moreover, we found that the marginal effects of self-rated health and pain were significant and much higher than other control variables, especially in the urban model

experimentandnumericalsimulationonthecharacteristicsoffluidstructureinteractionsofnonrigidairships

Fluid-structure interaction is an important issue for non-rigid airships with inflated envelopes. In this study, a wind tunnel test is conducted, and a loosely coupled procedure is correspondingly established for numerical simulation based on computational fluid dynamics and nonlinear finite element analysis methods. The typical results of the numerical simulation and wind tunnel experiment, including the overall lift and deformation, are in good agreement with each other. The results obtained indicate that the effect of fluid-structure interaction is noticeable and should be considered for non-rigid airships. Flowinduced deformation can further intensify the upward lift force and pitching moment, which can lead to a large deformation. Under a wind speed of 15 m/s, the lift force of the non-rigid model is increased to approximately 60% compared with that of the rigid model under a high angle of attack

Preparation of Silicon Carbide Powder from Amorphous Silica and Investigation of Synthesis Mechanism

An innovative process for preparing silicon carbide (SiC) from acid leaching residue of ferronickel slag through a carbon–thermal reduction process was proposed in this study. The results indicate that the acid leaching residue is an ideal silicon source for SiC preparation according to its high amorphous silica content of 84.20% and fine particle size of d50 = 29.16 μm. Compared with carbon black, activated carbon, and graphite, coke is the more appropriate carbon source for SiC preparation. A micron-size SiC powder with grade of 88.90% and an average particle size (d50) of 44.68 μm can be obtained under the following conditions: the mass ratio of coke to leaching residue as 1.2:1, in an air atmosphere, reducing at 1600 °C for 3 h, following by decarbonizing at 700 °C for 4 h. The XRD, SEM and FTIR analyses show that the prepared powder is 3C-SiC and belongs to the β-SiC crystal type. Based on thermodynamic analysis and micromorphology observation, it can be concluded that with amorphous silica as the silicon source, the carbon–thermal synthesis of SiC powder follows both the solid–solid reaction mechanism and the gas–solid mechanism. The SiC created through solid–solid reaction is primarily nucleated in situ on amorphous SiO2, with a size close to that of the original acid-leaching slag, while the SiC generated according to the gas–solid mechanism mainly nucleates heterogeneously on the surface of carbon particles, resulting in a smaller particle size and mostly adhering to the surface of solid–solid nucleated SiC particles. This study provides a feasible method for the effective utilization of amorphous silica, which is also significant for the efficient consumption of the vast acid leaching residue

Tuning diamond electronic properties for functional device applications

Because of its ultrahigh hardness, synthetic diamond has been widely used in advanced manufacturing and mechanical engineering. As an ultra-wide bandgap semiconductor, on the other hand, diamond recently shows a great potential in electronics industry due to its outstanding physical properties. However, like silicon-based electronics, the electrical properties of diamond should be well modulated before it can be practically used in electronic devices. In this work, we briefly review the recent progresses in producing high-quality, electronic grade synthetic diamonds, as well as several typical strategies, from the conventional element doping to the emerging “elastic strain engineering,” (ESE) for tuning the electrical and functional properties of microfabricated diamonds. We also briefly show some device application demonstrations of diamond and outline some remaining challenges that are impeding diamond’s further practical applications as functional devices and offer some perspective for future functional diamond development