Overexpression of NtEXPA7 promotes seedling growth and resistance to root-knot nematode in tobacco.

Root-knot nematode (RKN) is one of the most damaging plant pathogen in the world. They exhibit a wide host range and cause serious crop losses. The cell wall, encasing every plant cell, plays a crucial role in defending of RKN invasion. Expansins are a group of cell wall proteins inducing cell wall loosening and extensibility. They are widely involved in the regulation of plant growth and the response to biotic and abiotic stresses. In this study, we have characterized the biological function of tobacco (Nicotiana tabacum) NtEXPA7, the homologue of Solyc08g080060.2 (SlEXPA18), of which the transcription level was significantly reduced in susceptible tomato upon RKN infection. The expression of NtEXPA7 was up-regulated after inoculation of RKNs. The NtEXPA7 protein resided in the cell wall. Overexpression of NtEXPA7 promoted the seedling growth of transgenic tobacco. Meanwhile the increased expression of NtEXPA7 was beneficial to enhance the resistance against RKNs. This study expands the understanding of biological role of expansin in coordinate plant growth and disease resistance.

Design, Synthesis and Bioactivity of Novel Pyrimidine Sulfonate Esters Containing Thioether Moiety.

Pesticides play an important role in crop disease and pest control. However, their irrational use leads to the emergence of drug resistance. Therefore, it is necessary to search for new pesticide-lead compounds with new structures. We designed and synthesized 33 novel pyrimidine derivatives containing sulfonate groups and evaluated their antibacterial and insecticidal activities. Results: Most of the synthesized compounds showed good antibacterial activity against Xanthomonas oryzae pv. Oryzae (Xoo), Xanthomonas axonopodis pv. Citri (Xac), Pseudomonas syringae pv. actinidiae (Psa) and Ralstonia solanacearum (Rs), and certain insecticidal activity. A5, A31 and A33 showed strong antibacterial activity against Xoo, with EC50 values of 4.24, 6.77 and 9.35 µg/mL, respectively. Compounds A1, A3, A5 and A33 showed remarkable activity against Xac (EC50 was 79.02, 82.28, 70.80 and 44.11 µg/mL, respectively). In addition, A5 could significantly improve the defense enzyme (superoxide dismutase, peroxidase, phenylalanine ammonia-lyase and catalase) activity of plants against pathogens and thus improve the disease resistance of plants. Moreover, a few compounds also showed good insecticidal activity against Plutella xylostella and Myzus persicae. The results of this study provide insight into the development of new broad-spectrum pesticides.

Highly water-stable bimetallic organic framework MgCu-MOF74 for inhibiting bacterial infection and promoting bone regeneration.

As a typical metal-organic framework (MOF), Mg-MOF74 can release biocompatible Mg2+when the framework is degraded, and it has the potential to be used as filler in the field of bone tissue engineering. However, Mg-MOF74 has poor stability in aqueous environment and limited antibacterial ability, which limit its further development and applications. In this work, MgCu-MOF74 particles with different Cu content were synthesized through a facile one-step hydrothermal method. The physicochemical properties and water stability of the synthesized powders were characterized. The osteogenic potential of the MgCu-MOF74 particles on human osteogenic sarcoma cells (SaOS-2) was evaluated. The hybrid MgCu-MOF74 exhibited favorable water stability. These results indicated that MgCu-MOF74 enhanced cellular viability, alkaline phosphatase levels, collagen (COL) synthesis and osteogenesis-related gene expression. Moreover, the samples doped with Cu2+were more sensitive to the acidic microenvironment produced by bacteria, and exhibited stronger antibacterial ability than Mg-MOF74. In conclusion, MgCu-MOF-74 with good water stability, osteogenic ability and antibacterial ability, which could be attributed to the doping of Cu2+. Hence, MgCu-MOF74 shows great potential as a novel medical bio-functional fillers for the treatment of bone defects.

Rubidium-containing mesoporous bioactive glass scaffolds support angiogenesis, osteogenesis and antibacterial activity.

In this study, rubidium-containing mesoporous bioglass (Rb-MBG) scaffolds were formed with the investigation of the influence of Rb addition on angiogenic and osteogenic differentiation abilities of hBMSC. The phase composition, microstructure, pore size distribution, ion release, biological activity, drug loading rate, and release rate of Rb-MBG were characterized. The proliferation and differentiation of hBMSC, the markers of bone formation (ALP, COL-1) and angiogenesis (VEGF, HIF-1α), and wnt/ß-catenin related-signaling pathway gene were studied by cell culture. Rb-MBG loaded with antibacterial agents enoxacin (ENX), coliforms and Staphylococcus aureus were cultured together to study the antibacterial effects. The results indicate that the samples have a 350-550 µm large pore structure and 4.5-5.5 nm mesoporous size. Adding Rb can increase the activity of ALP, the secretion of VEGF and COLI, and the expression of HIF-1α of hBMSCs. Rb containing MBG is likely to enhance the proliferation and differentiation of hBMSCs through the influence of Wnt/ß-catenin signal path. Rb-MBG scaffold can load effectively and release Rb ions and ENX continuously to damage the bacterial cell membrane with the synergistic effect, and therefore achieve antibacterial results. In conclusion, adding Rb to MBG supports angiogenesis and osteogenesis of hBMSCs, as well as antibacterial activity.

p38 MAPK signaling pathway activation by phenyl benzoxime in SNU-306 cells causes induction of apoptosis.

The present study was aimed to investigate and understand the mechanism of inhibitory effect of phenyl benzoxime on proliferation of SNU-306 cells. Proliferation of SNU-306 cells transfected with wild-type p53-induced phosphatase 1 (Wip1)-siRNA or treated with phenyl benzoxime was examined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Induction of apoptosis was examined by flow cytometry using annexin V-fluorescein isothiocyanate/propidium iodide staining. In SNU-306 cells Wip1 mRNA and protein expression was found to be significantly (p < 0.05) higher compared to normal cells. However, Wip1-siRNA transfection significantly (p < 0.02) inhibited the expression of Wip1 at 60 nmol/l. The proliferation of SNU-306 cells was inhibited to 3.7% on transfection with Wip1-siRNA. Phenyl benzoxime reduced proliferation to 92.0, 75.0, 49.0, 19.0 and 4.0% at 1, 2, 4, 8 and 10 µM doses, respectively. The expression of Wip1 was significantly (p < 0.01) suppressed in SNU-306 cells on phenyl benzoxime treatment. Phenyl benzoxime induced apoptosis in 74.73% cells at 10 µM doses compared to 1.34% in control. Treatment with phenyl benzoxime markedly increased the expression of Bax, caspase-3 and p53 and decreased Bcl-2 mRNA. Moreover, addition of SB203580 to cultures of SNU-306 cells significantly (p < 0.01) prevented phenyl benzoxime mediated inhibition of cell proliferation. Phenyl benzoxime induces apoptosis and inhibits SNU-306 cell proliferation by silencing Wip1 expression through p38 MAPK signaling pathway activation. Therefore, phenyl benzoxime can act as an important chemotherapeutic agent for breast cancer treatment.

Synthesis and in vitro degradation of a novel magnesium oxychloride cement.

Magnesium oxychloride cement (MOC) has been used in civil engineering as it exhibits a relatively high early strength and a low coefficient of thermal expansion. Its poor water resistance, although, has prevented its widespread use. Steady degradation when immersed in an aqueous environment, however, could be a beneficial property for a resorbable bone replacement. In this study, we have evaluated how different concentrations of phosphoric acid may be used to enhance water resistance providing some control over the rate of degradation. The phase compositions, microstructures, mechanical properties, and the degradation of MOC have been evaluated. As a preliminary assessment of biological suitability, the response of a population of bone marrow stromal cells to the surface was evaluated. X-ray diffraction data demonstrate that 5Mg(OH)2 ·MgCl2·8H2O (phase 5) was formed in all MOC samples. The MOC modified with H3PO4 exhibits good water resistance and can sustain strength in aqueous medium and by adjusting H3 PO4 concentration; degradation speed may be controlled. Cells cultured on the surface of the MOC attached and retained viability over the duration of the study.