Nanotoxicity of different sizes of graphene (G) and graphene oxide (GO) in vitro and in vivo.

Graphene family nanomaterials (GFNs) have attracted significant attention due to their unique characteristics and applications in the fields of biomedicine and nanotechnology. However, previous studies highlighted the in vitro and in vivo toxicity of GFNs with size and oxidation state differences are still elusive. Therefore, we prepared graphene (G) and graphene oxide (GO) of three different sizes (S-small, M-medium, and L-large), and characterized them using multiple surface-sensitive analytical techniques. In vitro assays using HEK 293T cells revealed that the small and large sizes of G and GO significantly reduced the cell viability and increased DNA damage, accompanying with activated reactive oxygen species (ROS) generation and induced various expressions of associated critical genetic markers. Moreover, the bacterial assays highlighted that G and GO caused strong acute toxicity on Tox2 bacteria. Effects of G were higher than GO and showed size dependent effect: L > M > S, while the medium size of GO induced mild genetic toxicity on RecA bacteria. In vivo assays revealed that exposure to G and GO caused the developmental toxicity, induced ROS generation, and activated related pathways (specifically GO) in zebrafish. Taken together, G showed stronger ability to decrease the survival rate and induce the acute toxicity, while GO showed obvious toxicity in terms of DNA damages, ROS generation, and abnormal gene expressions. Our findings highlighted that G and GO differentially induced toxicity based on their varying physical characteristics, especially sizes and oxidation state, and exposure concentrations and sensitivity of the employed in vitro and in vivo models. In short, this study provided deep insights on the negative effects of GFNs exposure.

[Isolation, identification and diversity analysis of petroleum-degrading bacteria in Shengli Oil Field wetland soil].

The petroleum-degrading bacteria in Shengli Oil Field wetland soil were isolated and identified by traditional experiment methods, and their diversity was analyzed by PCR-DGGE (denaturing gradient gel electrophoresis). A total of thirteen petroleum-degrading bacterial strains were isolated, among which, six strains were found to have the ability of degrading the majority of C12-C26 petroleum hydrocarbon, with a degradation rate of > 90%. These petroleum degraders were phylogeneticly identified as the members of Halomonas, Alcanivorax, and Marinobacter, which were all belonged to gamma-proteobacteria. The uncultured predominant bacteria in Shengli Oil Field wetland soil were of Sulfurovum, Gillisia and Arcobacter. Among the predominant bacteria, gamma-proteobacteria accounted for a larger proportion, followed by alpha-proteobactiria, epsilon-proteobactiria, Actinobacteria, and Flavobacteria.