Decreased cadmium content in Solanum melongena induced by grafting was related to glucosinolates synthesis.

Grafting is an effective horticultural method to reduce Cd accumulation in crops. However, the mechanism of grafting inducing the decrease in Cd content in scions remains unclear. This study evaluated the effect of grafting on fruit quality, yield, and Cd content of Solanum melongena, and explored the potential mechanism of grafting reducing Cd content in scions. In the low Cd-contaminated soil, compared with un-grafted (UG) and self-grafted plants (SG), the fruit yield of inter-grafted plants (EG) increased by 38 %, and the fruit quality was not markedly affected. In EG, the decrease in total S and Cd content was not related to organic acids and thiol compounds. The decrease in total S and Cd content in EG leaves and fruits was closely related to the synthesis and transportation of glucosinolates (GSL). The genes encoding GSL synthesis in leaves, such as basic helix-loop-helix, myelocytomatosis proteins, acetyl-CoA, cytochrome P450, and glutathione S-transferases, were significantly downregulated. In EG leaves, the contents of five of the eight amino acids involved in GSL synthesis decreased significantly (P < 0.05). Notably, total GSL in EG stems, leaves, and fruits had a significant linear correlation with total S and Cd. In summary, the decrease in total S and Cd content in scions caused by grafting is closely related to GSL. Our findings provide a theoretical basis for the safe use of Cd-contaminated soil, exploring the long-distance transport of Cd in plants and cultivating crops with low Cd accumulation.

Grafting with an invasive Xanthium strumarium improves tolerance and phytoremediation of native congener X. sibiricum to cadmium/copper/nickel tailings.

Invasive plants could play an important role in the restoration of tailings, but their invasiveness limits their practical application. In this study, the phytoremediation potentials and invasive risks of an exotic invasive plant (Xanthium strumarium, LT), a native plant (X. sibiricum, CR), and combinations of inoculations (EG, with CR as the scion and LT as the rootstock; SG, with CR as both the scion and rootstock) were evaluated on Cd/Cu/Ni tailings. LT rootstock has a stronger nutrient and metal transport capacity, compared with CR. EG not only had higher biomass and Cd/Cu/Ni accumulation, but also abundant rhizosphere microbial communities. Hydroponic and common garden experiments showed that the growth and metal enrichment characteristics of EG are not inherited by plant offspring, which reduces the risk of the biological diffusion in the process of using exotic species. Transcriptome analysis shows that a large number of differentially-expressed genes in EG leaves and roots are involved in phenylpropanoid biosynthesis, secondary metabolite generation, and signal transduction. The genes induced in EG leaves, including cyclic nucleotide-gated ion channel, calcium-binding protein, and WRKY transcription factor, were found to be differentially expressed compared to CR. The genes induced in EG roots, included phenylalanine ammonia-lyase, cinnamoyl-CoA reductase, caffeoyl-CoA O-methyltransferase, and beta-glucosidase. We speculate that lignin and glucosinolates play an important role in the metal accumulation and transportation of EG. The results demonstrate that grafting with LT not only improved CR tolerance and accumulation of Cd, Cu, and Ni, but also created a beneficial microbial environment for plants in tailings. More importantly, grafting with LT did not enhance the invasiveness of CR. Our results provide an example of the safe use of invasive plants in the restoration of Cd/Cu/Ni tailings.

An Interaction between the Inner Rod Protein YscI and the Needle Protein YscF Is Required to Assemble the Needle Structure of the Yersinia Type Three Secretion System.

The type III secretion system is a highly conserved virulence mechanism that is widely distributed in Gram-negative bacteria. It has a syringe-like structure composed of a multi-ring basal body that spans the bacterial envelope and a projecting needle that delivers virulence effectors into host cells. Here, we showed that the Yersinia inner rod protein YscI directly interacts with the needle protein YscF inside the bacterial cells and that this interaction depends on amino acid residues 83-102 in the carboxyl terminus of YscI. Alanine substitution of Trp-85 or Ser-86 abrogated the binding of YscI to YscF as well as needle assembly and the secretion of effectors (Yops) and the needle tip protein LcrV. However, yscI null mutants that were trans-complemented with YscI mutants that bind YscF still assembled the needle and secreted Yops, demonstrating that a direct interaction between YscF and YscI is critical for these processes. Consistently, YscI mutants that did not bind YscF resulted in greatly decreased HeLa cell cytotoxicity. Together, these results show that YscI participates in needle assembly by directly interacting with YscF.

Chiral separation of racemic naproxen by high-performance liquid chromatography with beta-CD/SiO2 as the chiral stationary phase.

A novel derivative beta-cyclodextrin (beta-CD) bonded silica gel (beta-CD/SiO2) was prepared via carbodiimide activation and used as a chiral stationary phase (CSP). The beta-CD/SiO2 CSP was characterized by X-ray photoelectron spectroscopy and FTIR spectroscopy to prove the successful immobilization of beta-CD onto the surface of the silica gel. The thermal behavior of the CSP was studied by differential scanning calorimetry and then used for the chiral separation of racemic naproxen using HPLC. Several factors affecting the separation efficiency of naproxen enantiomers were investigated systematically. The following parameters were selected: methanol-0.01 M phosphate buffer solution (85 + 15, v/v, pH 3.5) was the mobile phase, the flow rate was 1.0 mL/min, and the column temperature was 35 degrees C. Under optimal conditions, the racemic naproxen was efficiently separated with a resolution factor (R(S)) of 1.70 and a separation factor (alpha) of 1.25. This method was successfully used for the enantiomeric separation and purity assessment of naproxen in commercial naproxen sustained release tablets.

[Effects of praeruptorin C on cell hypertrophy, intracellular [Ca2+]i, nitric oxide and signal transduction in isolated hypertrophied rat smooth muscle cells induced by angiotensin II].

AIM: To investigate the effects of praeruptorin C (Pra-C) on smooth muscle cell (SMC) hypertrophy, intracellular calcium ([Ca2+]i), nitric oxide (NO) content and influence on cellular signal transduction in isolated cultured rat smooth muscle cell (SMC). METHODS: Hypertrophied smooth muscle cells (HSMCs) were induced by angiotensin II (Ang II), cell area was measured under inverted microscope. Nitric oxide (NO) concentration was measured using Griess method. [Ca2+]i was measured using Fura-2/AM. The responses to [Ca2+]i elevation stimulated by KCl (60 mmol.L-1 or norepinephrine (10 mumol.L-1) were observed by incubation with phorbol 12-myristate 13-acetate (PMA), staurosporine (ST), the agonist and inhibitor of protein kinase C (PKC), and pertussis toxin (PTX), the sensitive toxin of Gi. RESULTS: The cell area of SMCs were decreased by 39.01% (P < 0.001) and NO content of SMCs were significantly increased in Pra-C + Ang II group. In presence of 60 mmol.L-1 KCl or 10 mumol.L-1 NE, [Ca2+]i of SMCs in Pra-C + Ang II group was significantly decreased than that of Ang II group (P < 0.001) and closed to the normal group. Incubation of SMCs with PMA, ST and PTX, [Ca2+]i of SMCs in Ang II group was increased by PMA and decreased by ST and PTX, but that of Pra-C + Ang II group was similar to the normal group. CONCLUSION: These findings suggest that Pra-C can reduce vascular hypertrophy in isolated rat HSMCs, and this is associated with improvement of SMCs [Ca2+]i level, NO content and cellular signal transdution of PKC and Gi.