Rui Qu,Huijie Hou,Keke Xiao,Bingchuan Liu,Sha Liang,Jingping Hu,Shijie Bian,Jiakuan Yang
The evaluation of ecological risks of contaminant mixtures to organisms is very challenging due to the non-linear response of organisms to each component, especially under the co-existence of both stimulators and inhibitors. Whether the stimulatory effect can reduce or even offset the inhibitory effect would be critical to the risk assessment and the treatment measures of mixed pollutants. Here, the combined toxicity of sodium fluoride (NaF), a stimulator with stimulation rate >100%, and six compounds that cannot induce hormesis (four ionic liquids (ILs) and two pesticides) were studied. The time-dependent toxicity of each toxicant on Vibrio qinghaiensis sp.-Q67 was investigated at 0.25, 2, 4, 6, 8, 10 and 12 h. Results showed that four ILs and two pesticides failed to induce hormesis, while NaF induced hormesis from 2 to 6 h and induced stimulation only after 6 h and reached its maximum (650%) at 12 h. All mixture rays with NaF induced hormesis at different times. In the four NaF-IL mixture systems, the absolute value of maximum stimulation demonstrated an upwards and then a downwards trend with the increasing of mixture ratio of IL. In two NaF-pesticide systems, the maximum stimulation effect declined with the increasing of the mixture ratio of pesticide. The toxicities of the mixture were successfully predicted by the improved inverse distance weighted interpolation, which are not able to be predicted by the commonly used concentration addition or independent action models. This paper shed lights on evaluating the hormesis of mixtures and the ecological risk of fluoride.
Yang Yi,Hao-Su Tang,Ying Sun,Wei Xu,Ting Min,Hong-Xun Wang
To explore the effects of phenolic binding on the structure and activity of lotus root polysaccharides (LRPs), five LRP-phenol complexes containing catechin (61.22 mg/g), gallic acid (9.37 mg/g), ferulic acid (29.28 mg/g), chlorogenic acid (83.80 mg/g) or caffeic acid (14.80 mg/g) were prepared via noncovalent intermolecular interaction, respectively. The interaction was confirmed by the differences among LRPs, phenols and their complexes in ultraviolet–visible and Fourier-transform infrared spectra. The phenolic binding caused significant changes in the molecular weight (MW) distribution and aggregation behavior of LRPs, particularly their average MW (34.49 kDa) increased by 3.73–8.30 times. Compared to LRPs, the complexes all showed stronger antioxidant activities. Notably, the binding of catechin improved the macrophage-stimulating effect of LRPs, specifically promoting the NO production at normal condition and inhibiting the NO overproduction induced by lipopolysaccharide. The noncovalent interaction with phenolic compounds is a promising method for the structural and functional improvement of LRPs.
Chemodynamic therapy (CDT), which uses metal ions to covert endogenous hydrogen peroxide into highly reactive hydroxyl radicals, is an newly-developing strategy for cancer therapy. However, poor drug delivery efficiency and restricted catalytic performance hinder the therapeutic potential of CDT. Herein, we constructed an in situ injectable hydrogel incorporating Fe/Mn-polydopamine nanoparticles and the ferroptosis inducer piperazine erastin (PE) (FMPEG) for mediating tumor-specific magnetic resonance imaging-visualized photothermal therapy (PTT)/CDT. Upon exposure to near-infrared light irradiation, FMPEG treatment exerted a PTT effect, which further accelerated the drug release behavior from FMP nanoparticles in response to the acidic tumor microenvironment. The released metal ions and PE enhanced the CDT effect at the tumor site. Furthermore, a long-term antitumor effect was obtained via the immunostimulatory effect of CDT/PTT by producing tumor-associated antigens. These findings, along with the unique advantages of injectable hydrogels in immune activation, prove the great potential of FMPEG administration as an efficient strategy for the clinical prevention of distant tumor metastasis of breast cancer.
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