Synthesis of A Novel Bridged Bis(β-cyclodextrin)s Possessing Phenan- throline Tether and Its Molecular Binding Ability with Dyes

A novel b-cyclodextrin dimer bearing 2, 9-diformyl-1, 10-phenanthroline tether 4 has been synthesized and its inclusion complexation behavior with two triangular model substrates (RhB and BG) has been investigated through fluorescence and ultraviolet spectrometry. The result obtained indicated that novel bridged bis(b-cyclodextrin)s could significantly enhance the original molecular binding ability of native b-cyclodextrin by cooperative binding of two hydrophobic cavities.

Tracing soil erosion with Fe_(3)O_(4) magnetic powder: Principle and application

Magnetic powder is regarded as an effective and economical tracer for estimating soil erosion.However,the principle and application for using magnetic powder to estimate soil erosion are still not fully developed.In this study,magnetic powders with mean diameters of both 30 and 1μm were mixed into three soils at different mass proportion.The relationship between magnetic susceptibility and the mass proportion of the introduced magnetic powder in the tagged soil,and the binding ability of magnetic powder to soil particles after both dry and wet sieving were investigated.The accuracy of tracking soil loss by using magnetic powder as a tracer was assessed.The results showed that there was a significant linear relationship between the magnetic susceptibility and the mass proportion of the introduced magnetic powder in the tagged soil.The relationship between the amount of soil captured by a magnet and the mass proportion of magnetic powder in the tagged soil indicated that soils were readily magnetized by magnetic powder,especially fine fractions.The magnetic susceptibility of magnetic powder in different sizes of soil aggregates was variable.A majority of magnetic powder of both 30 and 1μm diameters was strongly bound with fine particles<0.05 mm in dry and wet sieving.Using the estimated tracer mass proportions,the relative errors between measured and estimated soil losses with enrichment correction factor were less than 18.3%under the simulated rain events.This study not only reveal the principle of Fe_(3)O_(4) powder in soil erosion,but also improve its estimated precision of soil loss,which can make the tracing method by Fe_(3)O_(4) magnetic powder more useable in future.

Quantitative characterization of Cu binding potential of dissolved organic matter （DOM） in sediment from Taihu Lake using multiple techniques

Dissolved organic matter （DOM） plays an important role in heavy metal speciation and distribution in the aquatic environment especially for eutrophic lakes which have higher DOM concentration. Taihu Lake is the third largest freshwater and a high eutrophic lake in the downstream of the Yangtze River, China. In the lake, frequent breakout of algae blooms greatly increased the concentration of different organic matters in the lake sediment. In this study, sediment samples were collected from various part of Taihu Lake to explore the spatial difference in the binding potential of DOM with Cu. The titration experiment was adopted to quantitatively characterize the interaction between Cu（II） and DOM extracted from Taihu Lake sediments using ion selective electrode （ISE） and fluorescence quenching technology. The ISE results showed that the exogenous DOM had higher binding ability than endogenous DOM, and DOM derived from aquatic macrophytes had a higher binding ability than that derived from algae. The fluorescence quenching results indicated that humic substances played a key role in the complexation between DOM and Cu（II） in the lake. However, because of the frequent breakout of algae blooms, protein-like matters are also main component like hnmic matters in Taihu Lake. Therefore, the metals bound by protein-like substances should be caused concern as protein-like substances in DOM were unstable and they will release bound metal when decomposed.

Functional characterization of a Niemann-Pick type C2 protein in the parasitoid wasp Micropfitis mediator

Niemann-Pick type C2 （NPC2） is a type of small soluble protein involved in lipid metabolism and triglyceride accumulation in vertebrates and arthropods. Recent stud- ies have determined that NPC2 also participates in chemical communication of arthropods. In this work, two novel NPC2 proteins （MmedNPC2a and MmedNPC2b） in Microplitis mediator were identified. Real-time quantitative PCR （qPCR） analysis revealed that Mmed- NPC2a was expressed higher in the antennae than in other tissues of adult wasps compared with MmedNPC2b. Subsequent immunolocalization results demonstrated that NPC2a was located in the lymph cavities of sensilla placodea. To further explore the binding charac- terization of recombinant MmedNPC2a to 54 candidate odor molecules, a fluorescence binding assay was performed. It was found MmedNPC2a could not bind with selected fatty acids, such as linoleic acid, palmitic acid, stearic acid and octadecenoic acid. How- ever, seven cotton volatiles, 4-ethylbenzaldehyde, 3,4-dimethylbenzaldehyde, fl-ionone, linalool, m-xylene, benzaldehyde and trans-2-hexen-l-al showed certain binding abilities with MmedNPC2a. Moreover, the predicted 3D model of MmedNPC2a was composed of seven r-sheets and three pairs of disulfide bridges. In this model, the key binding residues for oleic acid in CjapNPC2 of Camponotus japonicus, Lue68, Lys69, Lys70, Phe97, Thr103 and Phe127, are replaced with Phe85, Ser86, His87, Leu113, Tyr119 and Ile143 in MmedNPC2a, respectively. We proposed that MmedNPC2a in M. mediator may play roles in perception of plant volatiles.