CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent m...CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent motif(PAM)at the target site.While xCas9,a variant derived from Streptococcus pyogenes Cas9(SpCas9),can recognize a broader range of PAMs,its application in non-model insects is lacking.In this study,we explored xCas9 activity in gene editing by selecting corazonin(Crz)and the target sites with various PAMs in Locusta migratoria,a destructive insect pest worldwide.We found that xCas9 could cleave the target site with AG PAM while SpCas9 could not,although xCas9 appeared to have lower activity than SpCas9 at the canonical NGG PAMs.The heritable homozygous Crz^(-/-)locust strain was generated by the application of xCas9.The Crz^(-/-)strain showed an albino body color,with significantly downregulated expression of several body color-related genes including Pale,Vermilion,Cinnabar,White andβ-carotene-binding protein.In addition,Crz^(-/-)mutants exhibited significantly reduced expression of Chitin synthase 1,along with a markedly lower chitin content as well as compact and rigid cuticles.Furthermore,Crz^(-/-)mutants displayed impaired performance under low-temperature stress,including prolonged lifespan,reduced body weight and smaller body size.Our results suggest that xCas9 is effective for insect genome editing,and Crz plays essential roles in insect body color,cuticle development and adaptation to low-temperature stress.The findings of this study extend the application of xCas9 in non-model insects and provide new insights into our understanding of the regulation of insect cuticle development and environmental adaptation.展开更多
The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x=0, 1, 2 wt.%） were studied. The results indicated the secondary phase Mgl7Al12 precipitated from the ...The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x=0, 1, 2 wt.%） were studied. The results indicated the secondary phase Mgl7Al12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50 ＋ xCa al- loys increased initially to its peak, and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature, the hardness of the AM50 ＋ 2Ca ahoy decreased, whereas the hardness of AM50 and AM50 ＋ 1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50 ＋ 1Ca alloys increased after aging treatment for the precipitation of Mg17Al12 phase, which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature, their tensile strengths increased. For AM50 ＋ 2Ca alloy, the tensile strength declined after aging at 150℃ and 175℃, while it increased slightly at 200℃. The ductility of AM50 ＋ xCa alloys （x = 0, 1, 2 wt.%） declined after aging treatment.展开更多
The effects of aging treatment on the microstructures and mechanical properties of extruded AM50+xCa alloys （x=0,1%,2% in mass fraction） were studied. The results indicated the secondary phase Mg 17 Al 12 precipitat...The effects of aging treatment on the microstructures and mechanical properties of extruded AM50+xCa alloys （x=0,1%,2% in mass fraction） were studied. The results indicated the secondary phase Mg 17 Al 12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50+xCa alloys increased initially to its peak,and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature,the hardness of the AM50+2Ca alloy decreased,whereas the hardness of AM50 and AM50+1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50+1Ca alloys increased after aging treatment for the precipitation of Mg 17 Al 12 phase,which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature,their tensile strengths increased. For AM50+2Ca alloy,the tensile strength declined after aging at 150?℃ and 175?℃,while it increased slightly at 200?℃. The ductility of AM50+xCa alloys （x=0,1%,2%） declined after aging treatment.展开更多
Two recently engineered SpCas9 variants, namely xCas9 and Cas9-NG, show promising potential in improving targeting specificity and broadening the targeting range. In this study, we evaluated these Cas9 variants in the...Two recently engineered SpCas9 variants, namely xCas9 and Cas9-NG, show promising potential in improving targeting specificity and broadening the targeting range. In this study, we evaluated these Cas9 variants in the model and crop plant, rice. We first tested xCas9-3.7, the most effective xCas9 variant in mammalian cells, for targeted mutagenesis at 16 possible NGN PAM (protospacer adjacent motif) combinations in duplicates. xCas9 exhibited nearly equivalent editing efficiency to wild-type Cas9 (Cas9-WT) at most canonical NGG PAM sites tested, whereas it showed limited activity at non-canonical NGH (H = A, C, T) PAM sites. High editing efficiency of xCas9 at NGG PAMs was further demonstrated with C to T base editing by both rAPOBECI and PmCDAI cytidine deaminases. With mismatched sgRNAs, we found that xCas9 had improved targeting specificity over the Cas9-WT. Furthermore, we tested two Cas9-NG variants, Cas9-NGv1 and Cas9-NG, for targeting NGN PAMs. Both Cas9-NG variants showed higher editing efficiency at most non-canonical NG PAM sites tested, and enabled much more efficient editing than xCas9 at AT-rich PAM sites such as GAT, GAA, and CAA. Nevertheless, we found that Cas9-NG variants showed significant reduced activity at the canonical NGG PAM sites. In stable transgenic rice lines, we demonstrated that Cas9-NG had much higher editing efficiency than Cas9-NGv1 and xCas9 at NG PAM sites. To expand the base-editing scope, we developed an efficient C to T base-editing system by making fusion of Cas9-NG nickase (D10A version), PmCDAI, and UGI. Taken together, our work benchmarked xCas9 as a high-fidelity nuclease for targeting canonical NGG PAMs and Cas9-NG as a preferred variant for targeting relaxed PAMs for plant genome editing.展开更多
New long phosphorescent phosphors Ba 1-xCa xAl 2O 4∶Eu 2+, Dy 3+ with tunable color emission were prepared and studied. The emission spectra show that the tuning range of the color emission of the phosphors i...New long phosphorescent phosphors Ba 1-xCa xAl 2O 4∶Eu 2+, Dy 3+ with tunable color emission were prepared and studied. The emission spectra show that the tuning range of the color emission of the phosphors is between 498 and 440 nm, which is dependent on x, under the excitation of UV. The wavelength of the afterglow increases with the increasing of x until x equals 0.6. The XRD patterns show that the single phase limit in the phosphors is below x value of 0 4. The Thermoluminescence spectra were measured to investigate the traps created by the doping of Dy 3+.展开更多
基金supported by the Key Research and Development Project of Henan Province,China(221111112200)the National Natural Science Foundation of China(32070502 and 32072419)+1 种基金the Fundamental Research Program of Shanxi Province,China(202303021224005)the Natural Science Foundation of Henan Province,China(232300420185).
文摘CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent motif(PAM)at the target site.While xCas9,a variant derived from Streptococcus pyogenes Cas9(SpCas9),can recognize a broader range of PAMs,its application in non-model insects is lacking.In this study,we explored xCas9 activity in gene editing by selecting corazonin(Crz)and the target sites with various PAMs in Locusta migratoria,a destructive insect pest worldwide.We found that xCas9 could cleave the target site with AG PAM while SpCas9 could not,although xCas9 appeared to have lower activity than SpCas9 at the canonical NGG PAMs.The heritable homozygous Crz^(-/-)locust strain was generated by the application of xCas9.The Crz^(-/-)strain showed an albino body color,with significantly downregulated expression of several body color-related genes including Pale,Vermilion,Cinnabar,White andβ-carotene-binding protein.In addition,Crz^(-/-)mutants exhibited significantly reduced expression of Chitin synthase 1,along with a markedly lower chitin content as well as compact and rigid cuticles.Furthermore,Crz^(-/-)mutants displayed impaired performance under low-temperature stress,including prolonged lifespan,reduced body weight and smaller body size.Our results suggest that xCas9 is effective for insect genome editing,and Crz plays essential roles in insect body color,cuticle development and adaptation to low-temperature stress.The findings of this study extend the application of xCas9 in non-model insects and provide new insights into our understanding of the regulation of insect cuticle development and environmental adaptation.
基金This work was financially supported by the International Cooperation Foundation of Shanghai Science and Technology Committee of China (No. 02SL002) and the Regional Council of Rhone-Alpes of France.
文摘The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x=0, 1, 2 wt.%） were studied. The results indicated the secondary phase Mgl7Al12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50 ＋ xCa al- loys increased initially to its peak, and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature, the hardness of the AM50 ＋ 2Ca ahoy decreased, whereas the hardness of AM50 and AM50 ＋ 1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50 ＋ 1Ca alloys increased after aging treatment for the precipitation of Mg17Al12 phase, which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature, their tensile strengths increased. For AM50 ＋ 2Ca alloy, the tensile strength declined after aging at 150℃ and 175℃, while it increased slightly at 200℃. The ductility of AM50 ＋ xCa alloys （x = 0, 1, 2 wt.%） declined after aging treatment.
文摘The effects of aging treatment on the microstructures and mechanical properties of extruded AM50+xCa alloys （x=0,1%,2% in mass fraction） were studied. The results indicated the secondary phase Mg 17 Al 12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50+xCa alloys increased initially to its peak,and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature,the hardness of the AM50+2Ca alloy decreased,whereas the hardness of AM50 and AM50+1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50+1Ca alloys increased after aging treatment for the precipitation of Mg 17 Al 12 phase,which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature,their tensile strengths increased. For AM50+2Ca alloy,the tensile strength declined after aging at 150?℃ and 175?℃,while it increased slightly at 200?℃. The ductility of AM50+xCa alloys （x=0,1%,2%） declined after aging treatment.
基金National Transgenic Major Project (2018ZX08020-003)the Sichuan Youth Science and Technology Foundation (2017JQ0005)+3 种基金the National Science Foundation of China (31771486)the Science Strength Promotion Program of UESTC to Y.Z.the Open Foundation of Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding (PL201801) to Y.Z. and T.Z.and the National Science Foundation Plant Genome Research Program (IOS-1758745) and USDA-NIFA Biotechnology Risk Assessment Research Program (2018-33522- 28789) to Y.Q.
文摘Two recently engineered SpCas9 variants, namely xCas9 and Cas9-NG, show promising potential in improving targeting specificity and broadening the targeting range. In this study, we evaluated these Cas9 variants in the model and crop plant, rice. We first tested xCas9-3.7, the most effective xCas9 variant in mammalian cells, for targeted mutagenesis at 16 possible NGN PAM (protospacer adjacent motif) combinations in duplicates. xCas9 exhibited nearly equivalent editing efficiency to wild-type Cas9 (Cas9-WT) at most canonical NGG PAM sites tested, whereas it showed limited activity at non-canonical NGH (H = A, C, T) PAM sites. High editing efficiency of xCas9 at NGG PAMs was further demonstrated with C to T base editing by both rAPOBECI and PmCDAI cytidine deaminases. With mismatched sgRNAs, we found that xCas9 had improved targeting specificity over the Cas9-WT. Furthermore, we tested two Cas9-NG variants, Cas9-NGv1 and Cas9-NG, for targeting NGN PAMs. Both Cas9-NG variants showed higher editing efficiency at most non-canonical NG PAM sites tested, and enabled much more efficient editing than xCas9 at AT-rich PAM sites such as GAT, GAA, and CAA. Nevertheless, we found that Cas9-NG variants showed significant reduced activity at the canonical NGG PAM sites. In stable transgenic rice lines, we demonstrated that Cas9-NG had much higher editing efficiency than Cas9-NGv1 and xCas9 at NG PAM sites. To expand the base-editing scope, we developed an efficient C to T base-editing system by making fusion of Cas9-NG nickase (D10A version), PmCDAI, and UGI. Taken together, our work benchmarked xCas9 as a high-fidelity nuclease for targeting canonical NGG PAMs and Cas9-NG as a preferred variant for targeting relaxed PAMs for plant genome editing.
文摘New long phosphorescent phosphors Ba 1-xCa xAl 2O 4∶Eu 2+, Dy 3+ with tunable color emission were prepared and studied. The emission spectra show that the tuning range of the color emission of the phosphors is between 498 and 440 nm, which is dependent on x, under the excitation of UV. The wavelength of the afterglow increases with the increasing of x until x equals 0.6. The XRD patterns show that the single phase limit in the phosphors is below x value of 0 4. The Thermoluminescence spectra were measured to investigate the traps created by the doping of Dy 3+.
