Synthesis, structure, theoretical calculation and antibacterial property of two novel Zn(II)/Ni(II) compounds based on 3, 5-dichlorosalicylaldehyde thiocarbamide ligand.

Two new compounds namely [Zn(L1)phen]31 and Ni(L1)phen(MeOH) 2 (L1 = 3, 5-dichlorosalicylaldehyde thiosemicarbazone) were synthesized by the slow evaporation method at room temperature. The structure of ligand L1 was determined using 1H NMR and 13C NMR spectra. X-ray single crystal diffraction analysis revealed that compounds 1-2 can form 3D supramolecular network structures through π···π stacking and hydrogen bonding interactions. The DFT calculation shows that the coordination of ligand and metal is in good agreement with the experimental results. Hirshfeld surface analysis revealed that H…H and Cl…H interactions were the predominant interactions in compounds 1-2. Energy framework analysis indicated that dispersion energy played a dominant role in the energy composition of compounds 1-2. The inhibitory effects of compounds 1-2 against Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA) were tested using the paper disk diffusion method (1: E. coli: 18 mm, MRSA: 17 mm, 2: E. coli: 15 mm, MRSA: 16 mm). Ion releasing experiments were conducted to assess the ion release capacity of compounds 1-2 (Zn2+, 4 days, 38.33 µg/mL; Ni2+, 4 days, 29.12 µg/mL). Molecular docking demonstrated the interaction modes of compounds 1-2 with UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and dihydrofolate reductase (DHFR) in bacteria, involving hydrophobic, stacking, hydrogen bonding and halogen bonding interactions. The generation of reactive oxygen species (ROS) in bacteria under the presence of compounds 1-2 were evaluated using a fluorescent dye known as dichlorodihydrofluorescein diacetate (DCFH-DA). Potential antibacterial mechanisms of compounds 1-2 were proposed.

Strategy of Graphdiyne (g-Cn H2n-2 ) Preparation Coupling with the Flower-Like NiAl-LDH Heterojunctions for Efficient Photocatalytic Hydrogen Evolution*.

Graphdiyne (g-Cn H2n-2 ), a novel two-dimension carbon allotrope material composed of a sp- and sp2 -hybrid carbon network, has been widely explored since it was synthesized for the first time by Li's group in 2010. A series distinct and excellent properties bestow graphdiyne excellent performance in many fields. Here, an innovative progress for preparing graphdiyne by using Cu+ contained material as catalyst is reported and the composite CuI-GD is coupled with flower-like NiAl-LDH to produce H2 from photocatalytic water splitting. The results of FTIR and Raman spectroscopy together reveal that graphdiyne nanosheets are synthesized successfully by employing a cross-coupling method. Photocatalytic hydrogen evolution performance shows that the hydrogen production activity of CuI-GD/NiAl-LDH has a 15- and 216-fold enhancement compared with CuI-GD and NiAl-LDH, respectively. A series of characterizations are carried out to expound the underlying reasons in the enhancement of the photocatalytic hydrogen production performance of CuI-GD/NiAl-LDH. Meanwhile, a possible mechanism for the photocatalytic hydrogen evolution process was proposed to understand the interaction among these materials.

Polydopamine coating on individual cells for enhanced extracellular electron transfer.

A new strategy of redox mediator immobilization was developed by coating polydopamine (PDA) on individual live cells to enhance extracellular electron transfer. As a result of the synergistic effect of the redox properties of PDA and the ability to adsorb self-secreted flavin molecules, a double-mediator electron transport channel was achieved.

[Pro-apoptotic effects of luteolin on hepatoma HepG2 cells].

OBJECTIVE: To investigate the effect of luteolin on cell growth and apoptosis of HepG2 cells in vitro. METHODS: Cultured HepG2,HL60,A549 and LO2 cells were treated with luteolin for different doses (0 µg/ml,2.5 µg/ml,10 µg/ml and 20 µg/ml) and varied times (0 h,24 h,48 h and 72 h). Cell viability was measured with MTT assay and IC50 was calculated. The reactive oxygen species (ROS) levels in HepG2 cells treated with luteolin for 6 h and 12 h were measured with flow cytometry. Cell apoptosis of HepG2 cells treated with luteolin for 24h was examined with flow cytometry and Annexin V-FITC/PI. Expression levels of apoptosis pathway proteins (p53,ASPP2 and iASPP) in HepG2 cells were detected with western blot and the dose and time-effect was analyzed. RESULTS: Luteolin effectively inhibited tumor cell proliferation in a dose-and time-dependent manner,and the inhibition rates of 20 µg/ml Luteolin for 72 h were 39.34%,62.90%,57.57% and 62.90% to LO2,HepG2, HL60 and A549 cells,respectively. The intracellular ROS level was decreased in HepG2 cells by 13.88% and 41.11% after being treated with luteolin for 6 h and 12 h,respectively. The apoptosis rate of HepG2 cells treated with luteolin for 24 h was 14.43%,and western blot showed that luteolin reduced the expression level of iASPP by 77.07% and up-regulated the expression of p53 by 179.37% and ASPP2 by 725.02% in HepG2 cells treated with luteolin for 12 h. CONCLUSION: Luteolin has ant-proliferative and pro-apoptotic activity on hepatoma HepG2 cells, which is associated with the altered expression of pro-apoptotic factors and decreased ROS level in HepG2 cells.

Magnetic solid-phase extraction and ultrafast liquid chromatographic detection of Sudan dyes in red wines, juices, and mature vinegars.

A nanocomposite of polystyrene-coated magnetic nanoparticles was successfully synthesized and employed as adsorbent for magnetic solid-phase extraction of four Sudan dyes (I, II III, and IV) in red wines, juices, and mature vinegars. The prepared magnetic nanoparticles with highly hydrophobic properties have excellent adsorption capacity for these lipophilic Sudan dyes. Extraction conditions were optimized. Experimental results showed that the recoveries of the four Sudan dyes were very satisfactory when 70 mg of polystyrene-coated magnetic nanoparticles were used and the extraction could be completed within 20 min. It was proved that these magnetic nanoparticles can be reused after an easy washing process. By coupling the magnetic solid-phase extraction with ultrafast liquid chromatography-ultraviolet spectrometry, a rapid, green, effective, and sensitive method for the determination of Sudan dyes was developed. The LOD for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.0039, 0.0063, 0.0057, and 0.017 ng/mL, respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.1, 1.0, and 10.0 ng/mL) were between 76.3 and 96.6%. The intra- and interday RSDs for the analytes were lower than 9.6%.

Electrochemical reclamation of silver from silver-plating wastewater using static cylinder electrodes and a pulsed electric field.

Silver was reclaimed from silver-plating wastewater by using a pulsed electric field (PEF) combined with static cylinder electrodes (SCE). The conditions that produced the maximal silver recovery rate (RR(Ag)) (99%) were as follows: average retention time of 10 min, interelectrode gap of 50mm, solution pH of 9.0, temperature of 45 degrees C, initial Ag(I) concentration of 1000 mg L(-1), PEF pulse frequency of 1200 Hz, current density of 5.0 A m(-2) and a pulse duty cycle of 60%. Compared with the conventional direct current (DC) technology, the PEF process exhibited improvements in the silver recovery rate (RR(Ag)), total energy consumption (TEC) and physical properties of the silver deposits, especially for low Ag(I) concentrations, for example, from 500 to 1000 mg L(-1). For an initial Ag(I) concentration of 500 mg L(-1), the PEF process produced an RR(Ag) of up to 99%, and the TEC was 4.56 kWh (kg Ag)(-1). In comparison, the RR(Ag) and TEC were 90% and 5.66 kWh (kg Ag)(-1), respectively, in the DC process. The results of SEM observation and XRD analysis indicated that the silver deposits formed by the PEF process were smaller, denser, and of a higher purity than those produced by the DC process. Therefore, the presented method was effective for reclaiming silver from silver-plating wastewater.

Heavy metal availability and impact on activity of soil microorganisms along a Cu/Zn contamination gradient.

All the regulations that define a maximum concentration of metals in the receiving soil are based on total soil metal concentration. However, the potential toxicity of a heavy metal in the soil depends on its speciation and availability. We studied the effects of heavy metal speciation and availability on soil microorganism activities along a Cu/Zn contamination gradient. Microbial biomass and enzyme activity of soil contaminated with both Cu and Zn were investigated. The results showed that microbial biomass was negatively affected by the elevated metal levels. The microbial biomass-C (C(mic))/organic C (C(org)) ratio was closely correlated to heavy metal stress. There were negative correlations between soil microbial biomass, phosphatase activity and NH4NO3 extractable heavy metals. The soil microorganism activity could be predicted using empirical models with the availability of Cu and Zn. We observed that 72% of the variation in phosphatase activity could be explained by the NH4NO3-extractable and total heavy metal concentration. By considering different monitoring approaches and different viewpoints, this set of methods applied in this study seemed sensitive to site differences and contributed to a better understanding of the effects of heavy metals on the size and activity of microorganisms in soils. The data presented demonstrate the relationship between heavy metals availability and heavy metal toxicity to soil microorganism along a contamination gradient.

Biosorption of copper(II) and zinc(II) from aqueous solution by Pseudomonas putida CZ1.

To study Pseudomonas putida CZ1, having high tolerance to copper and zinc on the removal of toxic metals from aqueous solutions, the biosorption of Cu(II) and Zn(II) by living and nonliving P. putida CZ1 were studied as functions of reaction time, initial pH of the solution and metal concentration. It was found that the optimum pH for Zn(II) removal by living and nonliving cells was 5.0, while it was 5.0 and 4.5, respectively, for Cu(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The adsorption data with respect to both metals provide an excellent fit to the Langmuir isotherm. The binding capacity of living cells is significantly higher than that of nonliving cells at tested conditions. It demonstrated that about 40-50% of the metals were actively taken up by P. putida CZ1, with the remainder being passively bound to the bacterium. Moreover, desorption efficiency of Cu(II) and Zn(II) by living cells was 72.5 and 45.6% under 0.1M HCl and it was 95.3 and 83.8% by nonliving cells, respectively. It may be due to Cu(II) and Zn(II) uptake by the living cells enhanced by intracellular accumulation.

Effect of copper-tolerant rhizosphere bacteria on mobility of copper in soil and copper accumulation by Elsholtzia splendens.

The role of rhizosphere bacteria in facilitating the solubility of copper (Cu) in contaminated soil and Cu accumulation in plant were studied. The bacteria strains were isolated from the rhizosphere of Elsholtzia splendens, a Cu accumulator growing on Tonglu Mountain copper mines. After the sandy soils containing 237 mg kg(-1) were incubated with the bacteria strains, it was indicated that rhizosphere microbes played an important role in influencing the availability of water-soluble Cu in soils. Soils had greater concentrations of water-extractable Cu compared with axenic soils inoculated with different bacterial strains. Further evidence for bacterial facilitation of increased solubility of Cu in the soil was obtained using the antibiotic ampicillin (0.1 mg g(-1)). There were 36% decreases in Cu concentration in the presence of bacterial strain MS12 and ampicillin together compared with bacterial inoculation alone. Different bacterial strains had different abilities on soil water-soluble Cu. To achieve the highest rates of plant Cu accumulation, it was necessary for bacteria to be present in the rhizosphere of E. splendens. Inoculated plants supplied with 20 micromol L(-1) CuSO4 had significantly greater concentrations of Cu in shoots and roots than uninoculated plants and bacterial strain MS2 was the most effective strain in promoting plant Cu uptake. There were 2.2-fold and 2.5-fold increases in Cu accumulation in the shoots and roots of plants inoculated with strain MS2 compared to axenic controls. Furthermore, when ampicillin and the bacterial strains were added together to the nutrient solution, the Cu concentrations in roots and shoots of ampicillin-treated plants were lower than those in inoculated plants. When ampicillin was added to the nutrient solution, Cu accumulation was inhibited by about 24-44% in shoots and 20-44% in roots. The above results provided a new insight into the phytoremediation of Cu-contaminated soil.

[Preliminary application of PCR-DGGE to analyzing microbial diversity in biofilters treating air loaded with ammonia].

As a new DNA fingerprinting technique, denaturing gradient gel electrophoresis (DGGE) can be used to analyze the microbial diversity in different environmental samples. Three biofilters treating air loaded with ammonia will be studied with respect to microbial diversity by applying cultivation-independent molecular methods DGGE. The principal objectives of this paper include the development and application of a suitable set of molecular tools to deliver information about the possible microbial community changes within carriers during treatment of ammonia-contaminated gas. Carriers were sampled at different time during operation of biofilters. After extraction and purification of the genomic DNA, the 16S rRNA genes (V3 region) were amplified by using the specific primers. These amplified DNA fragments were then separated by paralleled DGGE. The profile of DGGE showed that the same carrier at different time had the different bands' patterns. The structural diversity of the microbial community was examined by the Shannon index of general diversity H. Shannon indexes of three kinds of carriers all showed a decrease with time, which had a similar trend to NH3 removal efficiency.