Identification of salt-tolerant Sinorhizobium sp. strain BL3 membrane proteins based on proteomics.

Sinorhizobium sp. BL3 is a salt-tolerant strain that can fix atmospheric nitrogen in symbiosis with leguminous host plants under salt-stress conditions. Since cell membranes are the first barrier to environmental change, it is interesting to explore the membrane proteins within this protective barrier under salt stress. The protein contents of membrane-enriched fractions obtained from BL3 were analyzed by nanoflow liquid chromatography interfaced with electrospray ionization tandem mass spectrometry. A total of 105 membrane proteins were identified. These proteins could be classified into 17 functional categories, the two biggest of which were energy production and conversion, and proteins not in clusters of orthologous groups (COGs). In addition, a comparative analysis of membrane proteins between salt-stressed and non-stressed BL3 cells was conducted using a membrane enrichment method and off-line SCX fractionation coupled to nanoLC-MS/MS. These techniques would be useful for further comparative analysis of membrane proteins that function in the response to environmental stress

Effect of 457 nm Diode-Pumped Solid State Laser on the Polymerization Composite Resins: Microhardness, Cross-Link Density, and Polymerization Shrinkage

Objective: The purpose of the present study was to test the usefulness of 457 nm diode-pumped solid state (DPSS) laser as a light source to cure composite resins. Materials and methods: Five different composite resins were light cured using three different light-curing units (LCUs): a DPSS 457 nm laser (LAS), a light-emitting diode (LED), and quartz-tungsten-halogen (QTH) units. The light intensity of LAS was 560 mW/cm(2), whereas LED and QTH LCUs was ∼900 mW/cm(2). The degree of polymerization was tested by evaluating microhardness, cross-link density, and polymerization shrinkage. Results: Before water immersion, the microhardness of laser-treated specimens ranged from 40.8 to 84.7 HV and from 31.7 to 79.0 HV on the top and bottom surfaces, respectively, and these values were 3.3–23.2% and 2.9–31.1% lower than the highest microhardness obtained using LED or QTH LCUs. Also, laser-treated specimens had lower top and bottom microhardnesses than the other LCUs treated specimens by 2.4–19.4% and 1.4–27.8%, respectively. After ethanol immersion for 24 h, the microhardness of laser-treated specimens ranged from 20.3 to 63.2 HV on top and bottom surfaces, but from 24.9 to 71.5 HV when specimens were cured using the other LCUs. Polymerization shrinkage was 9.8–14.7 μm for laser-treated specimens, and these were significantly similar or lower (10.2–16.0 μm) than those obtained using the other LCUs. Conclusions: The results may suggest that the 457 nm DPSS laser can be used as a light source for light-curing dental resin composites