One new quaternary rare-earth sulfide, FeSm6Si2S（14）, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the noncentrosymmetric hexagonal space group P63, belon...One new quaternary rare-earth sulfide, FeSm6Si2S（14）, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the noncentrosymmetric hexagonal space group P63, belonging to the Ce6Al（3.33）S（14） structure-type, and the AxRE3MQ7 family. Its crystal structure features a 3-D framework constructed by SmS 8 bicapped trigonal prisms, where Fe and Si atoms occupy the octahedral（2a） and tetrahedral（2c） voids, respectively. The FeS 6 octahedra are connected with each other to form a chain along the b direction. FeSm6Si2S（14） represents a new chemical composition among the large family of AxRE3MQ7 compounds. The other related compounds containing transition metal are also discussed.展开更多
In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular aux...In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxinresponse machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell mainte-nance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 （WOX5）transcription factor modulates expression of auxin biosynthetic genes in the quiescent center （QC） of the root and thusprovides a robust mechanism for the maintenance of auxin response maximum in the root tip. This WOX5 action is bal-anced through the activity of indole-3-acetic acid 17 （IAA17） auxin response repressor. Our combined genetic, cell biol-ogy, and computational modeling studies revealed a previously uncharacterized feedback loop linking WOX5-mediatedauxin production to IAA17-dependent repression of auxin responses. This WOX5-1AA17 feedback circuit further assuresthe maintenance of auxin response maximum in the root tip and thereby contributes to the maintenance of distal stemcell （DSC） populations. Our experimental studies and in silico computer simulations both demonstrate that the WOX5-iAA17 feedback circuit is essential for the maintenance of auxin gradient in the root tip and the auxin-mediated root DSCdifferentiation.展开更多
基金supported by the Higher Education Science Foundation of Jiangsu Province(No.15KJB150031)State Key Laboratory of Structural Chemistry(No.20150009)Yangzhou Engineering Technology Research Center of Petrochemical New Materials(YZM2015086)
文摘One new quaternary rare-earth sulfide, FeSm6Si2S（14）, has been synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the noncentrosymmetric hexagonal space group P63, belonging to the Ce6Al（3.33）S（14） structure-type, and the AxRE3MQ7 family. Its crystal structure features a 3-D framework constructed by SmS 8 bicapped trigonal prisms, where Fe and Si atoms occupy the octahedral（2a） and tetrahedral（2c） voids, respectively. The FeS 6 octahedra are connected with each other to form a chain along the b direction. FeSm6Si2S（14） represents a new chemical composition among the large family of AxRE3MQ7 compounds. The other related compounds containing transition metal are also discussed.
文摘In plants, the patterning of stem cell-enriched meristems requires a graded auxin response maximum thatemerges from the concerted action of polar auxin transport, auxin biosynthesis, auxin metabolism, and cellular auxinresponse machinery. However, mechanisms underlying this auxin response maximum-mediated root stem cell mainte-nance are not fully understood. Here, we present unexpected evidence that WUSCHEL-RELATED HOMEOBOX 5 （WOX5）transcription factor modulates expression of auxin biosynthetic genes in the quiescent center （QC） of the root and thusprovides a robust mechanism for the maintenance of auxin response maximum in the root tip. This WOX5 action is bal-anced through the activity of indole-3-acetic acid 17 （IAA17） auxin response repressor. Our combined genetic, cell biol-ogy, and computational modeling studies revealed a previously uncharacterized feedback loop linking WOX5-mediatedauxin production to IAA17-dependent repression of auxin responses. This WOX5-1AA17 feedback circuit further assuresthe maintenance of auxin response maximum in the root tip and thereby contributes to the maintenance of distal stemcell （DSC） populations. Our experimental studies and in silico computer simulations both demonstrate that the WOX5-iAA17 feedback circuit is essential for the maintenance of auxin gradient in the root tip and the auxin-mediated root DSCdifferentiation.
