Basic Science

Breakthrough Achieved in Programming and Inheritance of Parental Epigenetic Modification in Mammals

It is a mystery how a fertilized egg can develop into an animal, which include more than 200 different cells with different phenotype and functions. DNA methylation is one major epigenetic modification which plays crucial roles during early embryogenesis. In 2013, Liu Jiang Group from the Beijing institute of Genomics, CAS uncovered that sperm DNA methylome is inherited by zebrafish early embryos (CELL, 2013). But limited was known on how offspring inherits the parental DNA methylome in mammals. Recently, Liu Jiang group collaborated with Huang Xingxu group from the Nanjing University, and revealed the principal on the programming and inheritance of parental DNA methylomes in mammals. Their studies changed the traditional knowledge in this field. The discoveries will have a big impact on the evolutionary, developmental and reproductive biology and human health. Their research result was published in journal CELL on May 8th, 2014.

Series of Progress Made on Electrochemical Effect of Nanocrystal Facets

In recent years, it is a hot topic to explore nanomaterials modified electrodes to realize highly sensitive and selective electrochemical detection of trace-level heavy metal ions in water. However, the increased currents and analytical sensitivity were generally thought to be an increased microscopic surface area. It was rarely reported about the essence of nanomaterials enhanced electrochemical response on the atomic scale. Recently, a series of progresses have been made in the novel electroanalysis method through metal oxide nanostructures exposed with different facets modified electrodes by the research group led by Prof. Liu Jinhuai and Prof. Huang Xingjiu at the Research Center for Biomimetic Functional Materials and Sensing Devices, Institute of Intelligent Machines, CAS. The research team found that metal oxide nanostructures with different exposed crystal facets modified electrodes could result in the selective electrochemical responses, and proposed the role of the effect of exposed nanocrystal facets in the electrochemical sensing of metal ions (Sci. Rep. 2013, 3, 2886; Electrochem. Commun. 2013, 34, 270). Based on the above achievements, the research group further investigated the electrochemical sensing mechanism of three types of α-Fe2O3 nanostructures including nanocubes, nanoplates, and nanorods with crystallographically dominant facets of {012}, {001}, and {110}, respectively, toward Pb2+ ion at the atomic-scale level with the combined experimental and theoretical efforts. Firstly, these three types of α-Fe2O3 nanostructures first designed and fabricated. Then, their electrochemical sensing performances were studied systematically. It was found interestingly that the electrochemical performances (e.g., sensitivity, limit of detection, etc.) of these α-Fe2O3 nanostructures depend on their exposed facets, and especially, the sensitivity can be ranked as “nanocube < nanoplate < nanorod”, which is consistent with the experimental results about adsorption. Furthermore, density functional theoretical calculation were carried out by Prof. Li Qunxiang at Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China. The calculation results demonstrated that different exposed facets held different surface energies, which influenced adsorption and diffusion behaviors of Pb2+, resulting in different electrochemical performances. These results revealed that the selective electrochemical response of heavy metal ions on different exposed crystal facets is attributed to the selective adsorption, which provides a new route to realize the improved sensitivity in electrochemical sensing of toxic metal ions. The experimental results have been published in Chemical Communications (Chem. Commun., 2014, 50, 5011-5013).