Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain ...Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain a deeper understanding of the genetic mechanism of lutein in marigold, a chromosome-scale assembly of the marigold(T. erecta V-01) genome was completed based on Illumina, PacBio, and Hi-C reads. The707.21-Mb assembled genome consisted of 35 834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs(covering 621.20 Mb) to 12 pseudochromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold was closely related to the Asteraceae species bitter vine(Mikania micrantha) and sunflower(Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade 23.57 million years ago(MYA) and from M. micrantha 19.59 MYA.Marigold has undergone three whole-genome duplication events, as well as a recent whole-genome duplication event(WGD-2) common to H.annuus and M. micrantha. Marigold gene families were significantly less expanded than those of M. micrantha or H. annuus, and the marigold genome contained significantly fewer interspersed repeats, which might account for its smaller genome. In addition, a range of candidate genes involved in the lutein biosynthetic pathway were identified. The high-quality reference genome obtained in this study provided a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.展开更多
In order to develop and utilize the tropical medicinal resource Amomum(A.)longiligulare T.L.Wu more reasonably and effectively,this paper summarizes the research progress in chemical constituents and pharmacological a...In order to develop and utilize the tropical medicinal resource Amomum(A.)longiligulare T.L.Wu more reasonably and effectively,this paper summarizes the research progress in chemical constituents and pharmacological activities of A.longiligulare by consulting the literatures,so as to provide a certain theoretical basis for exploring its material basis.The chemical constituents of A.longiligulare mainly include volatile oil,diphenylheptane and flavonoids,which have good efficacy in anti-peptic ulcer,as well as antioxidant,analgesic and other pharmacological activities.This paper briefly discusses the reasons for the differences in the composition of volatile oil studied by different scholars.By summarizing its pharmacological activities,it is found that its various pharmacological activities may be the basis of its anti-peptic ulcer.展开更多
本文首先简单介绍全数字化T/R组件应用场景,然后详细阐述了全数字化T/R组件发射通道的工作原理及关键技术,主要是直接数字合成技术(direct Digital Synthesize,DDS),之后提出了一种L波段(5.3GHz~5.9GHz)数字化T/R组件方案并给出原理框图...本文首先简单介绍全数字化T/R组件应用场景,然后详细阐述了全数字化T/R组件发射通道的工作原理及关键技术,主要是直接数字合成技术(direct Digital Synthesize,DDS),之后提出了一种L波段(5.3GHz~5.9GHz)数字化T/R组件方案并给出原理框图;再重点分析全数字化T/R组件发射通道的设计,包括:信道模块、发射前端、数字及控制单元设计,并出于一体化设计的考虑简单介绍了射频接收前端的设计思想;最后,对整个系统进行调测试,给出了实物照片和测试数据,测试结果表明该数字化T/R组件发射通道参数:工作带宽5.3GHz~5.9GHz,调制带宽1MHz~5MHz,移相范围0o~360o,最大衰减量15dB,最大输出峰值功率50W,最大工作占空比25%,杂散抑制大于60dBc,达到了指标要求,验证了数字化T/R组件发射通道的性能。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 31572166, 31772344, 31871691 and 31972444)。
文摘Marigold(Tagetes erecta L., African marigold) is a widely grown ornamental plant and a main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. To gain a deeper understanding of the genetic mechanism of lutein in marigold, a chromosome-scale assembly of the marigold(T. erecta V-01) genome was completed based on Illumina, PacBio, and Hi-C reads. The707.21-Mb assembled genome consisted of 35 834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs(covering 621.20 Mb) to 12 pseudochromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold was closely related to the Asteraceae species bitter vine(Mikania micrantha) and sunflower(Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade 23.57 million years ago(MYA) and from M. micrantha 19.59 MYA.Marigold has undergone three whole-genome duplication events, as well as a recent whole-genome duplication event(WGD-2) common to H.annuus and M. micrantha. Marigold gene families were significantly less expanded than those of M. micrantha or H. annuus, and the marigold genome contained significantly fewer interspersed repeats, which might account for its smaller genome. In addition, a range of candidate genes involved in the lutein biosynthetic pathway were identified. The high-quality reference genome obtained in this study provided a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.
基金supported by the National Natural Science Foundation of China(81660649),and Innovative Scientific Research Project for Postgraduates of Hainan Medical University(HYYS2020-05)。
文摘In order to develop and utilize the tropical medicinal resource Amomum(A.)longiligulare T.L.Wu more reasonably and effectively,this paper summarizes the research progress in chemical constituents and pharmacological activities of A.longiligulare by consulting the literatures,so as to provide a certain theoretical basis for exploring its material basis.The chemical constituents of A.longiligulare mainly include volatile oil,diphenylheptane and flavonoids,which have good efficacy in anti-peptic ulcer,as well as antioxidant,analgesic and other pharmacological activities.This paper briefly discusses the reasons for the differences in the composition of volatile oil studied by different scholars.By summarizing its pharmacological activities,it is found that its various pharmacological activities may be the basis of its anti-peptic ulcer.
文摘本文首先简单介绍全数字化T/R组件应用场景,然后详细阐述了全数字化T/R组件发射通道的工作原理及关键技术,主要是直接数字合成技术(direct Digital Synthesize,DDS),之后提出了一种L波段(5.3GHz~5.9GHz)数字化T/R组件方案并给出原理框图;再重点分析全数字化T/R组件发射通道的设计,包括:信道模块、发射前端、数字及控制单元设计,并出于一体化设计的考虑简单介绍了射频接收前端的设计思想;最后,对整个系统进行调测试,给出了实物照片和测试数据,测试结果表明该数字化T/R组件发射通道参数:工作带宽5.3GHz~5.9GHz,调制带宽1MHz~5MHz,移相范围0o~360o,最大衰减量15dB,最大输出峰值功率50W,最大工作占空比25%,杂散抑制大于60dBc,达到了指标要求,验证了数字化T/R组件发射通道的性能。
