| 3 | Effects of pyraclostrobin on growth,oxidative stress,and gene expression in relation to stress and ATP-binding cassette transporters in Tetrahymena thermophila显示文摘Pyraclostrobin(PYR),a widely used fungicide,has negative effects on fish and algae,but its toxicity in protozoa remains unclear.In this study,the effects of PYR on the growth,oxidative stress,and gene expression related to stress and ATP-binding cassette(ABC)transporters in Tetrahymena thermophila were investigated.The result showed that the 96-h IC_(50)of PYR against T.thermophila was 17.2 mg/L.Moreover,PYR inhibited the growth of T.thermophila in concentration-or time-dependent manner.A morphological study revealed that the shape and size of T.thermophila changed,and damage of cell membrane surface was observed by scanning electron microscopy after 96 h of PYR exposure.The activities of superoxide dismutase(SOD)and catalase(CAT)increased throughout the experiment.In contrast,the glutathione(GSH)content was increased at 24 h and 48 h of exposure and decreased at 96 h.Moreover,a significant increase in malondialdehyde(MDA)level was observed in T.thermophila after96 h of exposure.Furthermore,PYR upregulated the HSP703,HSP705,GPx2,and ABAC15 gene expression in the 0.1–5-mg/L groups and downregulated the HSP704,HSP90,TGR,and ABCC52 mRNA levels at 96 h of exposure.These results suggest that PYR may exert adverse effects on T.thermophila by inducing oxidative stress and changing the gene expression related to ABC transporters and stress,which may enrich the understanding of the toxicity mechanism of PYR in aquatic organisms and provide reference data for aquatic ecological risk assessments. | Yang LIU Jiale ZHANG Peng XIAO Xin LIU Yisifu MA Jing ZHANG Bangjun ZHANG | 2024 | Journal of Oceanology and Limnology2024，42，1： | 0 |
| 4 | Precise control of graphene etching by remote hydrogen plasma显示文摘Graphene with atomically smooth and configuration-specific edges plays the key role in the performance of graphene-based electronic devices.Remote hydrogen plasma etching of graphene has been proven to be an effective way to create smooth edges with a specific zigzag configuration.However,the etching process is still poorly understood.In this study,with the aid of a custom-made plasma-enhanced hydrogen etching(PEHE)system,a detailed graphene etching process by remote hydrogen plasma is presented.Specifically,we find that hydrogen plasma etching of graphene shows strong thickness and temperature dependence.The etching process of single-layer graphene is isotropic.This is opposite to the an isotropic etchi ng effect observed for bilayer and thicker graphe ne with an obvious depe ndence on temperature.On the basis of these observations,a geometrical model was built to illustrate the configuration evolution of graphene edges during etching,which reveals the origi n of the an isotropic etchi ng effect.By further utilizi ng this model,armchair graphe ne edges were also prepared in a con trolled manner for the first time.These investigations offer a better understanding of the etching process for graphene,which should facilitate the fabricati on of graphe ne?based electr onic devices with con trolled edges and the explorati on of more in teresti ng properties of graphe ne. | Bangjun Ma Shizhao Ren Peiqi Wang Chuancheng Jia Xuefeng Guo | 2019 | Nano Research2019，12，1： | 0 |
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