Reactive oxygen species

To investigate the effect of reactive oxygen species (ROS)/silent information regulator 1 (SIRT1) on hyperoxia-induced mitochondrial injury in BEAS-2B cells.

The experiment was divided into three parts. In the first part, cells were divided into H0, H6, H12, H24, and H48 groups. In the second part, cells were divided into control group, H48 group, H48 hyperoxia+SIRT1 inhibitor group (H48+EX 527 group), and H48 hyperoxia+SIRT1 agonist group (H48+SRT1720 group). In the third part, cells were divided into control group, 48-hour hyperoxia+N-acetylcysteine group (H48+NAC group), and H48 group. The ROS kit was used to measure the level of ROS. Western blot and immunofluorescent staining were used to measure the expression levels of SIRT1 and mitochondria-related proteins. Transmission electron microscopy was used to observe the morphology of mitochondria.

Compared with the H0 group, the H6, H12, H24, and H48 groups had a significantly increased fluorescence intensity of ROS (P<0.05), the H48 group had significant reductions in the expression levels of SIRT1 protein and mitochondria-related proteins (P<0.05), and the H24 and H48 groups had a significant reduction in the fluorescence intensity of mitochondria-related proteins (P<0.05). Compared with the H48 group, the H48+SRT1720 group had significant increases in the expression levels of mitochondria-related proteins and the mitochondrial aspect ratio (P<0.05), and the H48+EX 527 group had a significant reduction in the mitochondrial area (P<0.05). Compared with the H48 group, the H48+NAC group had a significantly decreased fluorescence intensity of ROS (P<0.05) and significantly increased levels of SIRT1 protein, mitochondria-related proteins, mitochondrial area, and mitochondrial aspect ratio (P<0.05).

The ROS/SIRT1 axis is involved in hyperoxia-induced mitochondrial injury in BEAS-2B cells.

Astragaloside IV (AS‐IV) is the most active monomer in the traditional Chinese herbal medicine Radix Astragali, which has a wide range of antiviral, anti‐inflammatory, and antifibrosis pharmacological effects, and shows protective effects in acute lung injury.

This study utilized the immunofluorescence, flow cytometry, enzyme‐linked immunosorbent assay, quantitative reverse transcription‐polymerase chain reaction, western blot, and hematoxylin and eosin staining methods to investigate the mechanism of AS‐IV in reducing viral pneumonia caused by influenza A virus in A549 cells and BALB/c mice.

The results showed that AS‐IV suppressed reactive oxygen species production in influenza virus‐infected A549 cells in a dose‐dependent manner, and subsequently inhibited the activation of nucleotide‐binding oligomerization domain‐like receptor thermal protein domain associated protein 3 inflammasome and Caspase‐1, decreased interleukin (IL) ‐1β and IL‐18 secretion. In BALB/c mice infected with Poly (I:C), oral administration of AS‐IV can significantly reduce Poly (I:C)‐induced acute pneumonia and lung pathological injury.

AS‐IV alleviates the inflammatory response induced by influenza virus in vitro and lung flammation and structural damage caused by poly (I:C) in vivo.

The emerging fluoroquinolone antibiotics (FQs) are highly influential in nitrogen removal from livestock wastewater. However, beyond the capability of nitrogen removal, little is known about the molecular mechanisms (e.g., shift of core metabolism and energy allocation) of different anaerobic ammonium-oxidizing bacteria (AnAOB) under continuous FQ stress. This study investigated the effects of ciprofloxacin, ofloxacin and their mixture at concentrations detected in livestock wastewater on two key anammox species in membrane bioreactors. It was found 20 μg/L FQs promoted nitrogen removal efficiency and community stability, and42-51 % of FQs were removed simultaneously. Integrated meta-omics analysis revealed varied gene expression patterns between the two dominant AnAOB, Candidatus Brocadia sapporoensis (B AnAOB) and Candidatus Kuenenia stuttgartiensis (K AnAOB). The nitrogen metabolic processes were bolstered in B AnAOB, while those involved in anammox pathway of K AnAOB were inhibited. This difference was tentatively attributed to the up-regulation of reactive oxygen species scavenger genes (ccp and dxf) and FQ resistance gene (qnrB72) in B AnAOB. Importantly, most enhanced core biosynthesis/metabolism of AnAOB and close cross-feeding with accompanying bacteria were also likely to contribute to their higher levels of biomass yield and metabolism activity under FQ stress. This finding suggests that B AnAOB has the advantage of higher nitrogen metabolism capacity over K AnAOB in livestock wastewater containing FQs, which is helpful for efficient and stable nitrogen removal by the functional anammox species.