Objective To clone and analyze the cDNA of major allergen Der f 2 of Dermatophagoides farinae in south China. Methods cDNA of Der f 2 was cloned by RT-PCR, screened and their sequences were analyzed. Results cDNAof Der f 2 was cloned. The sequence of the cloned Der f 2 was different with that published (D10448) in GenBank, with 87 additional nucleotides inserted into the 62th nucleotide of the original one. According to the original ORF, the deduced amino acids that were located prior or after the inserted 29 amino acid sequence showed no changes. Conclusion The cDNA of Der f 2 was cloned from Dermatophagoides farinae and its sequence showed significant difference with that reported in the GenBank.

OBJECTIVE：To predict the potenti al target and mechanism of Astragali Radix in the treatment of ulcerative colitis （UC），and to provide reference for the clinical application of Astragali Radix in the treatment of UC. METHODS ：The active components and their corresponding target genes of Astragali Radix were retrieved by TCMSP and UniProt KB database.related target genes of UC were searched by Gene Cards GZK-2018-5） database. The intersection target genes of Astragali Radix and were obtained by Venny 2.1.0 online mapping tool ，and interaction network of “drug-compound-intersection target ” was constructed by using Cytoscape 3.7.0 software. PPI network of intersecting targets was obtained by using STRING 结合动物模型。E-mail：172924249@qq.com database， and the visualization analysis and topological analysis w ere carried out by using Cytoscape 3.7.0 software to obtain the core target genes. By using DAVID database ，the gene ontology （GO） function annotation and KEGG pathway enrichment of intersecting target genes were carried out ，and the “target-pathway”enrichment network was constructed by using Cytoscape 3.7.0 software. Through Auto Dock vina 1.1.2 software， the top five active components in the list of degree value were linked with the protein encoded by the core target genes ；Discovery Studio 3.5 software was applied to draw out binding pattern map. RESULTS ：There were 143 compounds in Astragali Radix ，20 active components were screened out ，and 189 corresponding target genes were selected ；there were 4 356 UC disease related target genes. There were 126 intersection target genes of Astragali Radix （involving 14 active components ）and UC. The core target genes in PPI network were AKT1，MAPK1，RB1，JUN，etc. A total of 2 294 GO items （q value＜0.05）were obtained from GO functional annotation ，including 2 093 biological process items （e.g. response to lipopolysaccharide ，response to molecule of bacterial origin ），49 cell composition items （e.g. membrane raft ，membrane microdomain ），and 152 molecular function items （e.g. nuclear receptor activity ，ligand-activated transcription factor activity ）. KEGG pathway enrichment analysis yielded 160 items（q value＜0.05），such as fluid shear stress and atherosclerosis signaling pathway ，phosphatidylinositol 3 kinase/protein kinase B （PI3K/Akt） signaling pathway ，interleukin-17 （IL-17） signaling pathway. Molecular docking results showed that top 5 active ingredients （quercetin，kaempferol，formenonetin，isorhamnetin，7-O-methylisomucronulatol） in the list of degree value had binding energies ＜5.0 kcal/mol with the protein encoded core targets. CONCLUSIONS ：Quercetin，kaempferol，formononetin and other active components in Astragali Radix may play a role in the treatment of UC through the action of MAPK14，JUN，AKT1 and other target genes ，and then on the signal pathways such as PI 3K/Akt and IL- 17.