Antioxidant activity and enzyme inhibitory potential of Euphorbia resinifera and E. officinarum honeys from Morocco and plant aqueous extracts

Natural products may be applied in a wide range of domains, from agriculture to food and pharmaceutical industries. In this study, the antioxidant properties and the capacity to inhibit some enzymatic activities of Euphorbia resinifera and Euphorbia officinarum aqueous extracts and honeys were assessed. The physicochemical characteristics were also evaluated. Higher amounts of iron, copper and aluminium were detected in E. officinarum honey, which may indicate environmental pollution around the beehives or inadequate storage of honey samples. This honey sample showed higher amounts of total phenols and better capacity for scavenging superoxide anion free radicals and DPPH free radicals as compared with E. resinifera honey, but poorer capacity for inhibiting lipoxygenase, acetylcholinesterase, tyrosinase and xanthine oxidase. The ratio plant mass:solvent volume (1:100) and extraction time (1 - 2 h) were associated with higher total phenols and better antioxidant activities and lipoxygenase, acetylcholinesterase and tyrosinase inhibitory activities, regardless of the plant species. The aqueous extracts had systematically higher in vitro activities than the respective honey samples.

     

Uptake and distributions of polycyclic aromatic hydrocarbons in cultivated plants around an E-waste disposal site in Southern China

Environmental Science and Pollution Research - Polycyclic aromatic hydrocarbons (PAHs) in air, soil, and cultivated plants at e-waste disposal sites in Taizhou, Zhejiang Province, were determined...     

Applicability of LIVE/DEAD BacLight stain with glutaraldehyde fixation for the measurement of bacterial abundance and viability in rainwater

Rainwater contains substantial bacteria and rain is an efficient pathway for the dissemination of bacteria from the atmosphere to land and water surfaces.However,quantitative information on rainwater bacteria is very limited due to the lack of a reliable method.In this study,the epifluorescence microscopy enumeration with the LIVE/DEAD BacLight Bacterial Viability Kit stain was verified to quantify the abundance of viable and non-viable bacterial cells in rainwater,with the 4',6-diamidino-2-phenylindole(DAPI) stain for the reference of total cell counts.Results showed that the total counts of bacterial cells by LIVE/DEAD BacLight staining were consistent with those by DAPI staining,and the average detection efficiency was(109 ± 29)%.The ratio of cell count with glutaraldehyde fixation to that without fixation was(106 ± 5)%on average.The bacterial concentration in negative control was usually an order of magnitude lower than that in rainwater samples.However,in case of small precipitation,the abundance in negative control could be more than that in rainwater samples.These results indicate that the enumeration with LIVE/DEAD BacLight bacterial viability assay coupled with glutaraldehyde fixation and careful negative control investigation is an approach applicable to the measurement of the concentration and viability of bacterial cells in rainwater.     

Effect of oxide nanoparticles on the morphology and fluidity of phospholipid membranes and the role of hydrogen bonds

Engineered oxide nanoparticles (NPs) are widely applied in insulators, catalyzers, paints, cosmetic products, textiles and semiconductors. Their attachment on cell membrane may lead to cytotoxicity. The effects of Al₂O₃, Fe₂O₃, SiO₂, TiO₂ and ZnO NPs on membrane integrity and fluidity were studied using giant or small unilamellar vesicles in this study. Al₂O₃ and SiO₂ NPs disrupted the oppositely charged membrane, indicating the important role of electrostatic attraction. However, Fe₂O₃, TiO₂ and ZnO NPs did not cause serious membrane disruption as Al₂O₃ and SiO₂ NPs. Membrane fluidity was evaluated by the generalized polarity (GP) values of Laurdan fluorescent emission. SiO₂ NPs induce the membrane gelation of both positively and negatively charged membrane. Al₂O₃ and ZnO NPs induced the gelation of the oppositely charged membrane, but did not cause obvious membrane gelation to the like charged membrane. The phospholipid molecular structural changes after NP exposure were analyzed by Fourier transform infrared (FT-IR) spectroscopy. FT-IR spectra revealed the hydrogen bond formation between NPs and the carbonyl/phosphate groups of phospholipids. Al₂O₃ and SiO₂ NPs showed strongest evidence of hydrogen bonding on their FT-IR spectra. It was consistent with the microscopic observation and fluorescent data that Al₂O₃ and SiO₂ NPs caused more serious membrane disruption and gelation. This study on membrane damage provides further knowledge on the cytotoxicity of nanomaterials and the safety of NP application.     

紫外消毒对城市污水处理厂耐药菌去除的影响研究

通过选取假单胞杆菌、鲍曼不动杆菌以及芽孢杆菌3种耐药菌作为研究对象,研究紫外光变化对这3种耐药菌的去除效果,得出较好的紫外消毒条件,应用到实际的污水处理厂消毒过程中。结果表明,紫外消毒对3种耐药菌都有很好的灭活效果。     

不同主体功能定位的县域空间功能区划研究

文章通过判别分析法,尝试构建一套针对不同主体功能定位县通用的指标体系,以反映社会经济发展状况、生态环境保护重要性、国土空间开发支撑条件。通过在广西10个不同主体功能定位县的实践应用,将县域空间划分为城镇空间、农业空间和生态空间,重点开发区、农产品主产区、重点生态功能区的城镇空间分别小于30%、20%和10%,农产品主产区的农业空间和重点生态功能区的生态空间均大于50%。研究成果为全省范围推广县域空间功能区划提供了科学依据。     

Effects of Cu2+ and humic acids on degradation and fate of TBBPA in pure culture of Pseudomonas sp. strain CDT

Soil contamination with tetrabromobisphenol A(TBBPA) has caused great concerns;however, the presence of heavy metals and soil organic matter on the biodegradation of TBBPA is still unclear. We isolated Pseudomonas sp. strain CDT, a TBBPA-degrading bacterium, from activated sludge and incubated it with ~(14)C-labeled TBBPA for 87 days in the absence and presence of Cu~(2+)and humic acids(HA). TBBPA was degraded to organic-solvent extractable(59.4% ± 2.2%) and non-extractable(25.1% ± 1.3%) metabolites,mineralized to CO_2(4.8% ± 0.8%), and assimilated into cells(10.6% ± 0.9%) at the end of incubation. When Cu~(2+)was present, the transformation of extractable metabolites into non-extractable metabolites and mineralization were inhibited, possibly due to the toxicity of Cu~(2+)to cells. HA significantly inhibited both dissipation and mineralization of TBBPA and altered the fate of TBBPA in the culture by formation of HA-bound residues that amounted to 22.1% ± 3.7% of the transformed TBBPA. The inhibition from HA was attributed to adsorption of TBBPA and formation of bound residues with HA via reaction of reactive metabolites with HA molecules, which decreased bioavailability of TBBPA and metabolites in the culture. When Cu~(2+)and HA were both present, Cu~(2+)significantly promoted the HA inhibition on TBBPA dissipation but not on metabolite degradation. The results provide insights into individual and interactive effects of Cu~(2+)and soil organic matter on the biotransformation of TBBPA and indicate that soil organic matter plays an essential role in determining the fate of organic pollutants in soil and mitigating heavy metal toxicity.     

Study of cyanide removal from contaminated water using zinc peroxide nanomaterial

The present study highlights the potential application of zinc peroxide(ZnO_2)nanomaterial as an efficient material for the decontamination of cyanide from contaminated water. A process patent for ZnO_2 synthesis has been granted in United States of America(US Patent number 8,715,612; May 2014),South Africa,Bangladesh,and India. The ZnO_2 nanomaterial was capped with polyvinylpyrrolidone(PVP)to control the particle size. The PVP capped ZnO_2nanomaterial(PVP-ZnO_2)before and after adsorption of cyanide was characterized by scanning electron microscope,transmission electron microscope,X-ray diffractometer,Fourier transform infrared spectroscopy and time of flight-secondary ion mass spectrometry. The remaining concentration of cyanide after adsorption by PVP-ZnO_2 was determined using ion chromatograph. The adsorption of cyanide over PVP-ZnO_2 was also studied as a function of p H,adsorbent dose,time and concentration of cyanide. The maximum removal of cyanide was observed in p H range 5.8–7.8 within 15 min. The adsorption data was fitted to Langmuir and Fruendlich isotherm and it has been observed that data follows both the isotherms and also follows second order kinetics.     

A metal-free composite photocatalyst of graphene quantum dots deposited on red phosphorus

A simple approach to enhance the photocatalytic activity of red phosphorus(P) was developed.A mechanical ball milling method was applied to reduce the size of red P and to deposit graphene quantum dots onto red P. The product was characterized by scanning electron microscopy, transmission electron microscopy, contact angle measurements, zeta-potential measurements, X-ray diffraction and UV–vis absorption spectroscopy. The product exhibited high visible-light-driven photocatalytic performance in the photodegradation of rhodamine B.     

Construction of vesicle CdSe nano-semiconductors photocatalysts with improved photocatalytic activity: Enhanced photo induced carriers separation efficiency and mechanism insight

Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Vesicle Cd Se nano-semiconductor photocatalyst are successfully prepared by a gas template method and characterized by a variety of methods. The vesicle Cd Se nano-semiconductors display enhanced photocatalytic performance for the degradation of tetracycline hydrochloride, the photodegradation rate of78.824% was achieved by vesicle Cd Se, which exhibited an increase of 31.779% compared to granular Cd Se. Such an exceptional photocatalytic capability can be attributed to the unique structure of the vesicle Cd Se nano-semiconductor with enhanced light absorption ability and excellent carrier transport capability. Meanwhile, the large surface area of the vesicle Cd Se nano-semiconductor can increase the contact probability between catalyst and target and provide more surface-active centers. The photocatalytic mechanisms are analyzed by active species quenching. It indicates that h+and UO_2~-are the main active species which play a major role in catalyzing environmental toxic pollutants. Simultaneously, the vesicle Cd Se nano-semiconductor had high efficiency and stability.