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Efficient generation of zebrafish maternal-zygotic mutants through transplantation of ectopically induced and Cas9/gRNA targeted primordial germ cells

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Journal of Genetics and Genomics 2020年第1期47卷 37-47页

作者： Fenghua Zhang Xianmei Li Mudan He Ding Ye Feng Xiong Golpour Amin Zuoyan Zhu Yonghua Sun State Key Laboratory of Freshwater Ecology and Biotechnology Innovation Academy for Seed DesignInstitute of HydrobiologyChinese Academy of SciencesWuhan430072China College o f Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing100049China

The clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technology has been widely utilized for knocking out genes involved in various biological processes in zebrafish. Despite this technology is efficient for generating different mutations, one of the main drawbacks is low survival rate during embryogenesis when knocking out some embryonic lethal genes. To overcome this problem, we developed a novel strategy using a combination of CRISPR/Cas9 mediated gene knockout with primordial germ cell(PGC) transplantation(PGCT) to facilitate and speed up the process of zebrafish mutant generation, particularly for embryonic lethal genes. Firstly, we optimized the procedure for CRISPR/Cas9 targeted PGCT by increasing the efficiencies of genome mutation in PGCs and induction of PGC fates in donor embryos for PGCT. Secondly, the optimized CRISPR/Cas9 targeted PGCT was utilized for generation of maternal-zygotic(MZ) mutants of tcf7l1a(gene essential for head development), pou5f3(gene essential for zygotic genome activation) and chd(gene essential for dorsal development) at F1 generation with relatively high efficiency. Finally, we revealed some novel phenotypes in MZ mutants of tcf7l1 a and chd, as MZtcf7l1 a showed elevated neural crest development while MZchd had much severer ventralization than its zygotic counterparts. Therefore, this study presents an efficient and powerful method for generating MZ mutants of embryonic lethal genes in zebrafish. It is also feasible to speed up the genome editing in commercial fishes by utilizing a similar approach by surrogate production of CRISPR/Cas9 targeted germ cells.

关键词： Zebrafish CRISPR/Cas9 primordial germ cells Transplantation Maternal zygotic mutant

A Gravitational Wave Background from primordial Black Hole Lattices in Matter Dominated Era

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Communications in Theoretical Physics 2019年第10期71卷 1196-1204页

作者：王科 National Astronomical Observatories Chinese Academy of Sciences

We use the wide-used Einstein Toolkit to solve the Einstein constraints and then simulate the expansion of primordial black hole lattices(PBHLs) with different value of f PBH and m PBH. We find that f PBH plays an important role during the evolution of PBHLs. Since the motion of primordial black holes(PBHs) caused by the expansion of PBHLs occurs at speeds close to that of light, we expect the emission of gravitational waves(GWs) during the expansion of PBHLs. We use both analytical estimates and numerical simulations to cross check the production of GWs in expanding PBHLs.

关键词： Einstein Toolkit primordial black hole lattices gravitational waves

Measuring the tilt of primordial gravitational-wave power spectrum from observations

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 135-137页

作者： Jun Li Zu-Cheng Che Qing-Guo Huang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal UniversityChangsha 410081China

primordial gravitational waves (GWs) encode the information about inflation [1], and the power spectrum of primordial GWs have attracted a lot of attentions. There are in general two crucial properties for the primord... 详细信息

关键词： PTA BK Measuring the tilt of primordial gravitational-wave power spectrum from observations

primordial perturbations and non-gaussianities in Ho?ava-Lifshitz gravity

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Chinese Physics C 2019年第7期43卷 118-126页

作者：高显 School of Physics and Astronomy Sun Yat-sen University

We investigate primordial perturbations and non-gaussianities in the Horava-Lifshitz theory of gravitation.In the UV limit, the scalar perturbation in the Horava theory is naturally scale-invariant, ignoring the details of the expansion of the Universe. One may thus relax the exponential inflation and the slow-roll conditions for the inflaton field. As a result, it is possible that the primordial non-gaussianities, which are "slow-roll suppressed" in the standard scenarios, become large. We calculate the non-gaussianities from the bispectrum of the perturbation and find that the equilateral-type non-gaussianity is of the order of unity, while the local-type non-gaussianity remains small, as in the usual single-field slow-roll inflation model in general relativity. Our result is a new constraint on Horava-Lifshitz gravity.

关键词： cosmological perturbation theory primordial non-gaussianity Horava gravity inflation

Reprogramming of the pig primordial germ cells into pluripotent stem cells: a brief review

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Frontiers of Agricultural Science and Engineering 2019年第1期6卷 28-32页

作者： Qijing LEI Qin PAN Shuai YU Na LI Shulin CHEN Kuldip SIDHU Jinlian HUA College of Veterinary Medicine/Shaanxi Centre of Stem Cells Engineering and Technology Northwest A&F University Centre for Healthy Brain Ageing UNSW Medicine

primordial germ cells(PGCs) are regarded as unipotent cells that can produce only either spermatogonia or oocytes. However, PGCs can be converted into the pluripotent state by ?rst dedifferentiation to embryonic germ cells and then by reprogramming to induce them to become pluripotent stem cells(iPSCs). These two stages can be completely implemented with mouse cells. However, authentic porcine iPSCs have not been established.Here, we discuss recent advances in the stem cell ?eld for obtaining iPSCs from PGCs. This knowledge will provide some clues which will contribute to the regulation of reprogramming to pluripotency in farm species.

关键词： pig pluripotent stem cells primordial germ cells reprogramming

SUPERNOVAE AND THE MASS LOSS FROM primordial CLOUDS

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Science China Mathematics 1989年第5期32卷 585-595页

作者：马駬俞允强陈时 Beijing Astronomical Observatory Department of Physics Peking University Institute of Theoretical Physics Academia Sinica Beijing

The influence of supernova. (SN) explosions on the evolution of low mass primordialclouds is discussed. Because of the low escape velocity from a low mass cloud the radiativephase of SNR evolution has been taken into account. Making general assumptions about thestar formation rate and the initial mass function, the SN explosion rate has been calculated.The SN explosions will expel gas from a cloud in two ways: gradual boundary gas-drivingand sudden and complete gas loss by multiple SN explosions. The slower the star formationoccurs, the more important the boundary effect becomes. Numerical calculations on the va-riationof gas content with time show that if a low mass primordial cloud has a density aslow as that of the present epoch dwarf E galaxies, the cloud will be destroyed by the SNexplosions inside them. However, a high density cloud in the same mass range will losesome of its gas and evolve to a low surface brightness system which might be identifiedwith a present epoch dE galaxy.

关键词： supernovae mass loss primordial clouds.

Do Very Short Gamma Ray Bursts Originate from primordial Black Holes? Review

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International Journal of Astronomy and Astrophysics 2011年第3期1卷 164-172页

作者： David B. Cline Stanislaw Otwinowski Bozena Czerny Agnieszka Janiuk 不详

We present the state of current research of Very Short Gamma Ray Bursts (VSGRBs) from seven GRB detectors. We found that VSGRBs form distinct class of GRBs, which in our opinion, in most cases can originate from the evaporating primordial Black Holes (PBHs). Arguments supporting our opinion: 1) GRBs with time duration (T90) < 100 ms form distinct class: VSGRBs. 2) We observe significant anisotropy in the galactic angular distribution of BATSE VSGRB events. 3) V/Vmax distribution for BATSE VSGRB events indicates the local distance production. 4) VSGBBs have more energetic γ-ray burst than other GRBs with longer duration (KONUS). 5) We observe small number of afterglows in SWIFT VSGRB sample (25%), in contrast with the noticeable afterglow frequency in SGRB sample (78%). 6) Time profile of rising part BATSE VSGRBs is in agreement with the evaporation PBH model.

关键词： Black Hole Physics Cosmology Gamma Ray Burst primordial Black Hole

Chicken Mesenchymal Stem Cells as Feeder Cells Facilitate the Cultivation of primordial Germ Cells from Circulating Blood and Gonadal Ridge

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干细胞探索（英文） 2019年第1期9卷 1-14页

作者： Dongsheng Li Zhisheng Chen Shengfeng Chen Huiqin Ji Xiaoshu Zhan Dongzhang Luo Huina Luo Bingyun Wang School of Life Science and Engineering Foshan University Foshan China

Long-term maintenance of chicken primordial germ cells (PGCs) in vitro has tremendous potential for transgenic chicken production. Feeder cells are essential for the establishment and culture of chicken PGCs in vitro. Buffalo rat liver (BRL) cells are the most commonly used feeder cells for PGCs culture;however, this feeder layers from other animal species usually cause immunogenic contaminations, compromising the potential of PGCs in applications. Therefore, we tested chicken source mensenchymal stem cell (MSCs) derived from bone marrow as feeder cells to further improve PGC culture conditions. MSCs derived from chicken bone marrow have a powerful capacity to proliferate and secrete cytokines. We found chicken primordial germ cells derived from circulating blood (cPGCs) and gonads (gPGCs) can be maintained and proliferated with MSCs feeder layer cells. PGCs co-cultured on MSCs feeder retained their pluripotency, expressed PGCs specific genes and stemness markers, and maintained undifferentiated state. Our study indicated that the xeno-free MSCs-feeders culture system is a good candidate for growth and expansion of PGCs as the stepping stone for transgenic chicken research.

关键词： Chicken primordial Germ Cells Mensenchymal Stem Cells Transgenic

Formation of Galaxies in the Context of Gravitational Waves and primordial Black Holes

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Journal of Modern Physics 2019年第3期10卷 214-224页

作者： Shawqi Al Dallal Walid J. Azzam College of Graduate Studies and Research Ahlia University Manama Bahrain Department of Physics College of Science University of Bahrain Sakhir Bahrain

The recent discovery of gravitational waves has revolutionized our understanding of many aspects regarding how the universe works. The formation of galaxies stands as one of the most challenging problems in astrophysics. Regardless of how far back we look in the early universe, we keep discovering galaxies with supermassive black holes lurking at their centers. Many models have been proposed to explain the rapid formation of supermassive black holes, including the massive accretion of material, the collapse of type III stars, and the merger of stellar mass black holes. Some of these events give rise to the production of gravitational waves that could be detected by future generations of more sensitive detectors. Alternatively, the existence of these supermassive black holes can be explained in the context of primordial black holes. In this paper we discuss the various models of galaxy formation shedding light on the role that gravitational waves can play to test of the validity of some of these models. We also discuss the prospect of primordial black holes as a seeding constituent for galaxy formation.

关键词： Gravitational Waves Galaxy Formation primordial Black Holes Supermassive Black Holes