ABSTRACT
New dammarane-type triterpenoid saponin, named 22(R)-notoginsenoside Ab1 (1), together with thirteen known dammarane-type triterpenoid saponins (2-14) was isolated from the EtOH extract of black ginseng and their structures were elucidated on the basis of one- and two-dimensional NMR (including 1H-NMR, 13C-NMR, HSQC, HMBC, ROESY) and calculated ECD. Among them, compounds 1-2 and 6-8 were isolated for the first time from ginseng and black ginseng. Besides, the absolute structure of 22(R)- and 22(S)- notoginsenoside Ab1 were distinguished by ECD for the first time.
ABSTRACT
In this study, we characterized a WRKY family member gene, SsWRKY1, which is located in the nucleus and contains multiple stress-related cis-acting elements. In addition, constructed SsWRKY1-overexpressing Arabidopsis thaliana had higher antioxidant enzyme activity and proline content under drought stress conditions, with lower malondialdehyde content and reactive oxygen species (ROS) accumulation, and the expression levels of six stress-related genes were significantly upregulated. This indicates that the overexpression of SsWRKY1 in Arabidopsis thaliana improves resistance to drought stress. SsWRKY1 does not have transcriptional autoactivation activity in yeast cells. The yeast two-hybrid (Y2H) system and the S. spontaneum cDNA library were used to screen 21 potential proteins that interact with SsWRKY1, and the interaction between SsWRKY1 and ATAF2 was verified by GST pull-down assay. In summary, our results indicate that SsWRKY1 plays an important role in the response to drought stress and provide initial insights into the molecular mechanism of SsWRKY1 in response to drought stress.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Saccharum , Arabidopsis/genetics , Arabidopsis/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Saccharum/genetics , Drought Resistance , Plant Proteins/genetics , Plant Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Plants, Genetically Modified/genetics , Gene Expression Regulation, Plant , Droughts , Antioxidants/metabolism , Stress, Physiological/geneticsABSTRACT
A novel reverse osmosis (RO) composite membrane, poly(amide-urethane-imide@Ag) (PAUI@Ag), was prepared on a polysulfone supporting film through two-step interfacial polymerization. First, in the 1st interfacial polymerization procedure, a new tri-functional crosslinking agent with -OCOCl and -COCl groups, 5-choroformyloxyisophaloyl chloride (CFIC), was reacted with 4-methyl-phenylenediamine (MMPD) without curing treatment to obtain the poly(amide-urethane) base membrane with a CFIC-MMPD precursor separation layer. And then N,N'-dimethyl-m-phenylenediamine (DMMPD) with nano-Ag particle dispersion was introduced onto the base membrane to further construct a CFIC-DMMPD modified ultrathin separation layer via the 2nd interfacial polymerization. Thus, the PAUI@Ag RO membrane with poly(amide-urethane-imide) bi-layer skin was obtained. The membrane was characterized for the chemical composition of separation layer, the membrane cross-section structure and the membrane surface morphology. Permeation experiment was employed to evaluate the PAUI@Ag membrane performance including salt rejection rate and water flux. The results revealed that the PAUI@Ag membrane composed the highly cross-linked separation layer with entire ridges and valleys, small surface roughness, and well dispersed nano-Ag particles. Upon exposure of the membranes to high concentration of free chlorine solutions, the PAUI@Ag RO membrane showed a slightly less chlorine-resistant property compared with the nascent PAUI RO membrane, but was still superior to the conventional polyamide MPD-TMC RO membrane, meanwhile it processed higher anti-biofouling property.