Synthesis of Se polysaccharide catalyzed by sulfonic acid functionalized ionic liquids: Synergism effect of anion/cation.

The rational design and construction of controllable selenylation strategy are important for the study on the structure-activity relationship of Se polysaccharides. Herein, selenized Artemisia sphaerocephala polysaccharides (SePASs) were synthesized by using sulfonic acid functionalized ionic liquids (SFILs) as catalysts in order to study the regulation of the cation/anion constitute on the selenylation efficiency and Se polysaccharide structure. Impressively, SFILs could promote the efficient substitution of seleno-group on the polysaccharide backbone through the synergistic catalysis by cation/anions (Se content up to 5582.7 µg/g). Further, reaction mechanism and potential dissolution effect was supported by DFT calculation and polarized light microscopy. 13C NMR and FT-IR spectra analysis of SePASs exhibited that selenite existed in polysaccharides and the substitution position occured at C-6. SEC-MALLS, monosaccharide composition results revealed that strong acidity of SFILs lead to the driving forces toward low molecular mass polysaccharide fragments and synergistic effect of anion/cations in SFILs (-SO3H group of cations as proton donor, anions as nucleophile) showed regulation on average molecular mass. In addition, the strong attractions between the seleno-groups generated agglomeration of polysaccharide chain, which was proved by applying AFM analysis. Therefore, this work provided a new insight for manipulate Se content and MW of Se polysaccharides.

An easily-performed high-throughput method for plant genomic DNA extraction.

Genomic DNA isolation is a crucial technique for researchers studying plant molecular biology. A current widely-used protocol for DNA extraction needs a pestle and mortal for each sample and consumes a large amount of liquid nitrogen in grinding the samples. Most high-throughput methods depend on expensive machines for tissue homogenization. Here we developed a CTAB-based DNA extraction method using 2.0 mL microcentrifuge tubes for sample processing. This protocol has the advantages that it is suitable for a variety of plants, easily-performed without special equipment, and high-throughput; it effectively avoids sample cross-contamination, and is inexpensive, rapid and safe.

A novel, easy and rapid method for constructing yeast two-hybrid vectors using In-Fusion technology.

Yeast two-hybrid systems are powerful tools for analyzing interactions between proteins. Vector construction is an essential step in yeast two-hybrid experiments, which require bait and prey plasmids. In this study, we modified the multiple cloning site sequence of the yeast plasmid pGADT7 by site-directed mutagenesis PCR to generate the pGADT7-In vector, which resulted in an easy and rapid method for constructing yeast two-hybrid vectors using the In-Fusion cloning technique. This method has three key advantages: only one pair of primers and one round of PCR are needed to generate bait and prey plasmids for each gene, it is restriction endonuclease- and ligase-independent, and it is fast and easily performed.