ABSTRACT
Brassica campestris Male Fertility 20 (BcMF20) is a typical zinc-finger transcription factor that was previously isolated from flower buds of Chinese cabbage (Brassica campestris ssp. chinensis). By applying expression pattern analysis, it can be known that BcMF20 was specifically and strongly expressed in tapetum and pollen, beginning from the uninucleate stage, and was maintained during the mature-pollen stage. As BcMF20 was highly conserved in Cruciferae, it can be indicated that this zinc-finger transcription factor is important during the growth of Cruciferae. In this study, 12 C2H2-type zinc-finger TFs which shared high homology with BcMF20 were found from NCBI via BLAST. A new molecular phylogenetic tree was constructed by the comparison between BcMF20 and these 12 C2H2-type zinc-finger TFs with NJ method. By analyzing this phylogenetic tree, the evolution of BcMF20 was discussed. Then, antisense RNA technology was applied in the transgenesis of Arabidopsis thaliana to get the deletion mutants of BcMF20, so that its function during the pollen development can be identified. The results showed: BcMF20 are in the same clade with three genes from Arabidopsis. The inhibition of BcMF20 expression led to smaller amounts of and lower rate in germination of pollen and lower rate in fruit setting in certain transgenetic plants. This also led to the complete collapse of pollen grains. By SEM and TEM, pollen morphology and anther development processes were observed. In the middle uninucleate microspore stage, a relatively thin or even no primexine was formed in microspores. This may result in the malformation of the pollen wall and finally cause the deformity of pollens. Above all, it can be indicated that BcMF20 may act as a part of regulation mechanisms of TAZ1 and MS1. Together they play a role in a genetic pathway in the tapetum to act on proliferation of tapetal cells and keep the normal development of pollens.
Subject(s)
Brassica/genetics , Germination , Plant Proteins/genetics , Pollen/genetics , Transcription Factors/genetics , Brassica/growth & development , Brassicaceae/genetics , Brassicaceae/growth & development , Gene Expression Regulation, Plant , Genes, Plant , Phylogeny , Pollen/growth & development , Zinc FingersABSTRACT
Three Ag(I)-organic frameworks, [Ag5(pydc)2(CN)]n, {[Ag4(pydc)2]CH3CN}n, and [Ag(4,4'-bpy)NO3]n, were synthesized and embedded into silica gels to form metal-organic-framework (MOF)-embedded gels for the microextraction of polybrominated diphenyl ethers (PBDEs) in soils. Despite the great differences in the structures of the organic ligands, all three Ag(I)-organic frameworks were found to effectively accumulate and concentrate PBDEs from sample solutions prepared with contaminated soil and purified water, indicating the important roles of Ag centers in PBDE extraction. Under the optimal experimental conditions (MOF mass, water volume, temperature, extraction time, and back-extraction time) for PBDE extraction from sample solutions, the detection limits of seven PBDEs (BDE-28, 47, 99, 100, 153, 154, and 183) ranged from 0.01 to 2.6ngg(-1) for [Ag5(pydc)2(CN)]n, 0.20-0.64ngg(-1) for {[Ag4(pydc)2]CH3CN}n, and 0.60-3.08ngg(-1) for [Ag(4,4'-bpy)NO3]n. The reproducibilities of the three methods were all satisfactory with relative standard deviations (RSDs) in the range of 2.2-9.6%, 5.3-10.4%, and 6.9-9.4% for [Ag5(pydc)2(CN)]n, {[Ag4(pydc)2]CH3CN}n, and [Ag(4,4'-bpy)NO3]n, respectively. The use of Ag(I)-organic frameworks for the microextraction of PBDEs was validated using both certified reference soils and field-contaminated soils, and the proposed methods are recommended as rapid and environmentally friendly alternatives for the extraction and determination of PBDEs in soils.
Subject(s)
Chromatography, Gas , Environmental Monitoring/methods , Halogenated Diphenyl Ethers/analysis , Organic Chemicals/chemistry , Silica Gel/chemistry , Silver/chemistry , Soil Pollutants/analysis , Halogenated Diphenyl Ethers/isolation & purification , Soil Pollutants/isolation & purification , Solid Phase Microextraction , Temperature , Water/chemistryABSTRACT
OBJECTIVE: To study the chemical constituents from leaves of Phyllostachys pubescens. METHOD: Column chromatography on sephadex LH-20 as well as preparative HPLC and spectral analysis were used to isolate and elucidate the constituents. RESULT: Six compounds were isolated from leaves of Phyllostachys pubescens, and identified as vanillin (I), syringic aldehyde (II), p-hydroxybenzaldehyde (III), vanillic acid (IV), syringic acid (V), 4-hydroxy-3-methoxy cinnamic acid, ethyl ester (VI). CONCLUSION: All above the compounds were isolated from the plant for the first time.