Small mutations in the core promoter region of a gene may result in substantial changes in expression strengths.However,targeting TA-rich sequences of core promoters may pose a challenge for Cas9 variants such as SpCa...Small mutations in the core promoter region of a gene may result in substantial changes in expression strengths.However,targeting TA-rich sequences of core promoters may pose a challenge for Cas9 variants such as SpCas9 and other G-rich PAM-compatible Cas9s.In this study,we engineered a unique FrCas9 system derived from Faecalibaculum rodentium for plant genome editing.Our findings indicate that this system is efficient in rice when the TATA sequence is used as a PAM.In addition,FrCas9 demonstrated activity against all 16 possible NNTA PAMs,achieving an efficiency of up to 35.3%in calli and generating homozygous or biallelic mutations in 31.3%of the T_(0)transgenic plants.A proof-ofconcept experiment to examine editing of the rice WX core promoter confirmed that FrCas9-induced mutations could modify gene expression and amylose content.Multiplex mutations and deletions were produced by bidirectional editing,mediated by FrCas9,using a single palindromic TATA sequence as a PAM.Moreover,we developed FrCas9-derived base editors capable of programmable conversion between AT and GC pairs in plants.This study highlights a versatile FrCas9 toolset for plant core promoter editing,offering great potential for the fine-tuning of gene expression and creating of new germplasms.展开更多
The influence of source concrete (SC) with different compression strengths on the workability and mechanical properties of recycled mortar made with river sand substituted by 100% fine recycled concrete aggregates (FR...The influence of source concrete (SC) with different compression strengths on the workability and mechanical properties of recycled mortar made with river sand substituted by 100% fine recycled concrete aggregates (FRCA) is experimentally investigated. The basic physical performance test shows that with the increase in SC strength, FRCA exhibit lower water absorption and crushing index, meanwhile keeping higher densities. Mechanical property tests, including compressive strength, flexural strength and uniaxial compressive stress-strain tests, show that compressive strength,flexural strength and elasticity modulus of recycled sand mortars increase roughly with the increase in SC strength. The proposed mixture design method demonstrates that all of the components can be kept as the same as those in natural mortar mixture design and FRCA must be pre-wetted before making mortar mixture. Meanwhile, the reuse of higher strength SC can ensure that recycled mortar mixtures are able to achieve similar mechanical performance when compared to natural mortar designs.展开更多
应用模糊控制理论,研究了ATM网络的流量管理问题。将ABR(Available Bit Rate)业务的流量控制抽象为一时滞系统的控制问题,提出了一种模糊速率流量控制算法,实现了带宽在各个ABR虚连接中公平有效地分配。仿真结果表明算法具有良好的综合...应用模糊控制理论,研究了ATM网络的流量管理问题。将ABR(Available Bit Rate)业务的流量控制抽象为一时滞系统的控制问题,提出了一种模糊速率流量控制算法,实现了带宽在各个ABR虚连接中公平有效地分配。仿真结果表明算法具有良好的综合性能。展开更多
基金funded by the Improved Varieties Joint Research(Rice)Project of Anhui Province(the 14th five-year plan),the National Key Research and Development Program(2022YFF1002803)the National Natural Science Foundation of China(No.32300343,32000284,and 32270430)+1 种基金the Natural Science Foundation of Anhui Province(No.2208085Y11 and 2308085Y20)the Innovative Research Team of Anhui Education(No.2022AH010056).
文摘Small mutations in the core promoter region of a gene may result in substantial changes in expression strengths.However,targeting TA-rich sequences of core promoters may pose a challenge for Cas9 variants such as SpCas9 and other G-rich PAM-compatible Cas9s.In this study,we engineered a unique FrCas9 system derived from Faecalibaculum rodentium for plant genome editing.Our findings indicate that this system is efficient in rice when the TATA sequence is used as a PAM.In addition,FrCas9 demonstrated activity against all 16 possible NNTA PAMs,achieving an efficiency of up to 35.3%in calli and generating homozygous or biallelic mutations in 31.3%of the T_(0)transgenic plants.A proof-ofconcept experiment to examine editing of the rice WX core promoter confirmed that FrCas9-induced mutations could modify gene expression and amylose content.Multiplex mutations and deletions were produced by bidirectional editing,mediated by FrCas9,using a single palindromic TATA sequence as a PAM.Moreover,we developed FrCas9-derived base editors capable of programmable conversion between AT and GC pairs in plants.This study highlights a versatile FrCas9 toolset for plant core promoter editing,offering great potential for the fine-tuning of gene expression and creating of new germplasms.
基金The National Key Research and Development Programm of China(No.2018YFD1100402-05)the National Natural Science Foundation of China(No.6505000184)
文摘The influence of source concrete (SC) with different compression strengths on the workability and mechanical properties of recycled mortar made with river sand substituted by 100% fine recycled concrete aggregates (FRCA) is experimentally investigated. The basic physical performance test shows that with the increase in SC strength, FRCA exhibit lower water absorption and crushing index, meanwhile keeping higher densities. Mechanical property tests, including compressive strength, flexural strength and uniaxial compressive stress-strain tests, show that compressive strength,flexural strength and elasticity modulus of recycled sand mortars increase roughly with the increase in SC strength. The proposed mixture design method demonstrates that all of the components can be kept as the same as those in natural mortar mixture design and FRCA must be pre-wetted before making mortar mixture. Meanwhile, the reuse of higher strength SC can ensure that recycled mortar mixtures are able to achieve similar mechanical performance when compared to natural mortar designs.
