Assessing protein oxidation by inorganic nanoparticles with enzyme-linked immunosorbent assay (ELISA)

Oxidative stress response in pulmonary cells exposed to different fractions of PM2.5-0.3 from urban, traffic and industrial sites

The aim of this work was to study the relationship between oxidative stress damages and particulate matter (PM) chemical composition, sources, and PM fractions. PM_2.5-0.3 (PM with equivalent aerodynamic diameter between 2.5 and 0.3 μm) were collected at urban, road traffic and industrial sites in the North of France, and were characterized for major and minor chemical species. Four different fractions (whole PM_2.5-0.3, organic, water-soluble and non-extractable matter) were considered for each of the PM_2.5-0.3 samples from the three sites. After exposure of BEAS-2B cells to the four different fractions, oxidative stress was studied in cells by quantifying reactive oxygen species (ROS) accumulation, oxidative damage to proteins (carbonylated proteins), membrane alteration (8-isoprostane) and DNA damages (8-OHdG). Whole PM_2.5-0.3 was capable of inducing ROS overproduction and caused damage to proteins at higher levels than other fractions. Stronger cell membrane and DNA damages were found associated with PM and organic fractions from the urban site. ROS overproduction was correlated with level of expression of carbonylated proteins, DNA damages and membrane alteration markers. The PM_2.5-0.3 collected under industrial influence appears to be the less linked to cell damages and ROS production in comparison with the other influences.

Zn-doped CuO nanocomposites inhibit tumor growth by NF-κB pathway cross-linked autophagy and apoptosis

AIM

To investigate the antitumor effects and action mechanism of Zn-doped CuO nanocomposites (Zn-CuONPs).

MATERIALS & METHODS

Therapeutic effects and mechanisms of Zn-CuONPs were investigated both in vitro and in vivo.

RESULTS

Zn-CuONPs could inhibit tumor growth both in vitro and in vivo significantly. Zn-CuONPs treatment resulted in cytotoxicity, reactive oxygen species (ROS) production, DNA damage, apoptosis and autophagy. ROS scavenger N-acetylcysteine attenuated all of the above effects induced by Zn-CuONPs. N-acetylcysteine also restored the effects of Zn-CuONPs on protein expressions related to apoptosis, autophagy and NF-κB pathways. NF-κB pathway inhibitor pyrrolidine dithiocarbamate significantly attenuated Zn-CuONPs induced apoptosis and autophagy.

CONCLUSION

Our data demonstrated that Zn-CuONPs could inhibit tumor growth both in vitro and in vivo by ROS-dependent apoptosis and autophagy cross-linked by NF-κB pathways.

A review of the fate of engineered nanomaterials in municipal solid waste streams

Significant knowledge and data gaps associated with the fate of product-embedded engineered nanomaterials (ENMs) in waste management processes exist that limit our current ability to develop appropriate end-of-life management strategies. This review paper was developed as part of the activities of the IWWG ENMs in Waste Task Group. The specific objectives of this review paper are to assess the current knowledge associated with the fate of ENMs in commonly used waste management processes, including key processes and mechanisms associated with ENM fate and transport in each waste management process, and to use that information to identify the data gaps and research needs in this area. Literature associated with the fate of ENMs in wastes was reviewed and summarized. Overall, results from this literature review indicate a need for continued research in this area. No work has been conducted to quantify ENMs present in discarded materials and an understanding of ENM release from consumer products under conditions representative of those found in relevant waste management process is needed. Results also indicate that significant knowledge gaps associated with ENM behaviour exist for each waste management process investigated. There is a need for additional research investigating the fate of different types of ENMs at larger concentration ranges with different surface chemistries. Understanding how changes in treatment process operation may influence ENM fate is also needed. A series of specific research questions associated with the fate of ENMs during the management of ENM-containing wastes have been identified and used to direct future research in this area.

Biomarkers of oxidative damage in bacteria for the assessment of sanitation efficacy in lettuce wash water

In the fresh produce industry, validation of sanitation efficacy is critical to prevent cross-contamination of produce. The current validation approaches are either based on time-consuming plate counting assays or indirect measurements of chemical properties of wash water. In the study, the focus was to identify biomarkers that can provide direct assessment of oxidative damage in bacteria upon exposure to sanitizers in the presence of fresh produce and correlation of these oxidative biomarkers with logarithmic inactivation of bacteria. Two endogenous bacterial biomarkers, protein carbonylation and thiol oxidation, were evaluated for assessing oxidative damage in Escherichia coli O157:H7 and Listeria innocua during sanitation of pre-cut lettuce leaves with NaOCl or H2O2. Results show that NaOCl treatment was more effective than H2O2 for oxidation of both the intracellular thiols and protein carbonylation in the selected strains. Statistical analysis of the measurements illustrates that oxidation of the intracellular thiol induced by NaOCl or H2O2 was correlated with logarithmic reduction of E. coli O157:H7 and L. innocua. In contrast, changes in the protein carbonylation content were not correlated with reduction in bacterial cell viability. In summary, these results provide a novel approach to validate sanitation efficacy for the fresh produce industry.

Toxicity of metal oxide nanoparticles: mechanisms, characterization, and avoiding experimental artefacts

Metal oxide nanomaterials are widely used in practical applications and represent a class of nanomaterials with the highest global annual production. Many of those, such as TiO2 and ZnO, are generally considered non-toxic due to the lack of toxicity of the bulk material. However, these materials typically exhibit toxicity to bacteria and fungi, and there have been emerging concerns about their ecotoxicity effects. The understanding of the toxicity mechanisms is incomplete, with different studies often reporting contradictory results. The relationship between the material properties and toxicity appears to be complex and diifficult to understand, which is partly due to incomplete characterization of the nanomaterial, and possibly due to experimental artefacts in the characterization of the nanomaterial and/or its interactions with living organisms. This review discusses the comprehensive characterization of metal oxide nanomaterials and the mechanisms of their toxicity.