Allergenicity of recombinant Humulus japonicus pollen allergen 1 after combined exposure to ozone and nitrogen dioxide.

Ozone (O3) and nitrogen dioxide (NO2) are thought to play primary roles in aggravating air pollution-induced health problems. However, the effects of joint O3/NO2 on the allergenicity of pollen allergens are unclear. Humulus japonicus pollen allergen 1 (Hum j1) is a profilin protein that causes widespread pollinosis in eastern Asia. In order to study the effects of combined O3/NO2 on the allergenicity of Hum j1, tandem six-histidine peptide tag (His6)-fused recombinant Hum j1 (rHum j1) was expressed in a prokaryotic system and purified through His6 affinity chromatography. The purified rHum j1 was used to immunize SD rats. Rat sera with high titers of IgG and IgE antibodies against rHum j1 were used for allergenicity quantification. The rHum j1 was exposed to O3/NO2, and changes in allergenicity of the exposed rHum j1 were assayed using the immunized rat antibodies. Tandem LC-MS/LC (liquid chromatography-mass spectrometer/liquid chromatography spectrometer) chromatography and UV and circular dichroism (CD) spectroscopy were used to study the structural changes in rHum j1. Our data demonstrated that a novel disulfide bond between the sulfhydryl groups of two neighboring cysteine molecules was formed after the rHum j1 exposure to joint O3/NO2, and therefore IgE-binding affinity was increased and the allergenicity was reinforced. Our results provided clues to elucidate the mechanism behind air pollution-induced increase in pollinosis prevalence.

Distribution, fate, and risk assessment of antibiotics in five wastewater treatment plants in Shanghai, China.

The project studied the occurrence, fate, and seasonal variation of 14 antibiotics, from five wastewater treatment plants (WWTPs) in Shanghai. The results indicated that ofloxacin, sulfamethoxazole, and oxytetracycline were the predominant antibiotics, with maximum concentrations of 1208.20, 959.13, and 564.30 ng/L in influents, while 916.88, 106.60, and 337.81 ng/L in effluents, respectively. The level of antibiotics in WWTPs obviously varied with seasonal changes, and higher detectable frequencies and concentrations were found in winter. The daily mass loads per capita of amoxicillin, enrofloxacin, and oxytetracycline in the study were all higher than those in other regions/countries, such as Hong Kong, Australia, and Italy. The elimination of antibiotics through these WWTPs was incomplete, and a wide range of removal efficiencies during the different treatment process and seasons were observed (-500.56 to 100 % in winter and -124.24 to 94.21 % in summer). Sulfonamides were relatively easy to be removed in WWTPs and the ultraviolet (UV) process can effectively improve the removal efficiency. Risk assessment of antibiotics in effluents was estimated. Only AMOX's hazard quotient (HQ) was higher than 0.01. Even though the environmental risks in the study were estimated to be low, the potential negative effects on aquatic ecosystems should call our attention as continually discharge in the long term.

Excess titanium dioxide nanoparticles on the cell surface induce cytotoxicity by hindering ion exchange and disrupting exocytosis processes.

To date, considerable effort has been devoted to determine the potential toxicity of nanoparticles to cells and organisms. However, determining the mechanism of cytotoxicity induced by different types of nanoparticles remains challenging. Herein, typically low toxicity nanomaterials were used as a model to investigate the mechanism of cytotoxicity induced by low toxicity nanomaterials. We studied the effect of nano-TiO2, nano-Al2O3 and nano-SiO2 deposition films on the ion concentration on a cell-free system simulating the cell membrane. The results showed that the ion concentration of K(+), Ca(2+), Na(+), Mg(2+) and SO4(2-) decreased significantly following filtration of the prepared deposition films. More specifically, at a high nano-TiO2 concentration (200 mg L(-1)) and a long nano-TiO2 deposition time (48 h), the concentration of Na(+) decreased from 2958.01 to 2775.72, 2749.86, 2757.36, and 2719.82 mg L(-1), respectively, for the four types of nano-TiO2 studied. Likewise, the concentration of SO4(2-) decreased from 38.83 to 35.00, 35.80, 35.40, and 35.27 mg L(-1), respectively. The other two kinds of typical low toxicity nanomaterials (nano-Al2O3 and nano-SiO2) have a similar impact on the ion concentration change trend. Adsorption of ions on nanoparticles and the hydrated shell around the ions strongly hindered the ions through the nanoparticle films. The endocytosed nanoparticles could be released from the cells without inducing cytotoxicity. Hindering the ion exchange and disrupting the exocytosis process are the main factors that induce cytotoxicity in the presence of excess nano-TiO2 on the cell surface. The current findings may offer a universal principle for understanding the mechanism of cytotoxicity induced by low toxicity nanomaterials.

[Perspectives on synergic biological effects induced by ambient allergenic pollen and urban fine/ultrafine particulate matters in atmosphere].

Ambient particulate matters (PM) and allergenic pollens in urban atmosphere have taken negative effects on human health and air quality. Studies on synergistic effects between the two pollutants are being focused in disciplines, such as atmospheric sciences, environmental toxicology, and immunology. In this study, physicochemical characterization of airborne fine/ultrafine particles in Shanghai, China and ambient allergenic pollens (cedar) in Kanto, Japan were investigated. We found that allergenic protein particles (Ubisch body) with diameter less than 0.7 microm were absorbed on Japanese cedar pollen, and airborne particles which contained allergenic particles mainly distributed in < 1 microm size range. The highest mass concentration of chemical elements in Shanghai airborne particles was found in the 0.3-0.18 microm size range, but mass level of pollutant elements, such as S and Pb, in ambient in ultrafine (nano) particles were higher than that in coarse and fine particles. And also, pollen particles were found in Shanghai airborne particles. Synergistic effects between diesel exhaust particles (DEPs), which were the main component in urban airborne particles, and ambient pollens in urban atmosphere can be found, but their mechanism have not been clear. After our new results and other conclusions published recently on allergenic pollen and airborne fine/ultrafine particles were summarized, perspectives of this new discipline were presented.

Ultrathin alumina membranes for surface nanopatterning in fabricating quantum-sized nanodots.

Using ultrathin alumina membranes (UTAMs) as evaporation or etching masks large-scale ordered arrays of surface nanostructures can be synthesized on substrates. However, it is a challenge for this technique to synthesize quantum-sized surface structures. Here an innovative approach to prepare UTAMs with regularly arrayed pores in the quantum size range is reported. This new approach is based on a well-controlled pore-opening process and a modulated anodization process. Using UTAMs with quantum-sized pores for the surface patterning process, ordered arrays of quantum dots are synthesized on silicon substrates. This is the first time in realizing large-scale regularly arrayed surface structures in the quantum size range using the UTAM technique, which is an important breakthrough in the field of surface nanopatterning.