Development of a Fast Method Using Inductively Coupled Plasma Mass Spectrometry Coupled with High-Performance Liquid Chromatography and Exploration of the Reduction Mechanism of Cr(VI) in Foods.

Hexavalent chromium (Cr(VI)) is known as the most hazardous species of chromium. Speciation analysis of Cr in foods is of a great significance for assessing its influences on human health. In this study, a fast HPLC-ICP-MS method for the determination of Cr(VI) was developed for determining the content of Cr(VI) and also investigating its transformation in foods. The developed method employs an alkali extraction and weak anion-exchange column separation for distinguishing the Cr species, facilitating accurate Cr(VI) quantification within 1.5 min. This technique was applied to determine the Cr(VI) levels in a range of food products, including yoghurt, milk powder, rice flour, orange juice, green tea, white vinegar, and whole wheat bread. The results showed that no Cr(VI) was detected in these food products. Spiking experiments revealed that the recovery rate of Cr(VI) decreased with the increase in its contact time with food products. A further exploration of Cr(VI) in various food components such as vitamin C, tea polyphenols, whey proteins, gelatin, fructose, and cellulose indicated the conversion of Cr(VI) to organic Cr(III) over a period from 20 min to 60 h. It was found that high temperatures and acidic conditions accelerated the rate of Cr(VI) conversion to organic Cr(III) in the six food components mentioned above. This evidence suggests that natural reducing substances in foods probably prevent the occurrence of Cr(VI).

Combined effects of copper and cadmium exposure on ovarian function and structure in Nile Tilapia (Oreochromis niloticus).

With the rapid development of industrialization and urbanization, the issue of copper (Cu) and cadmium (Cd) pollution in aquatic ecosystems has become increasingly severe, posing threats to the ovarian tissue and reproductive capacity of aquatic organisms. However, the combined effects of Cu and Cd on the ovarian development of fish and other aquatic species remain unclear. In this study, female Nile tilapia (Oreochromis niloticus) were individually or co-exposed to Cu and/or Cd in water. Ovarian and serum samples were collected at 15, 30, 60, 90, and 120 days, and the bioaccumulation, ovarian development, and hormone secretion were analyzed. Results showed that both single and combined exposure significantly reduced the gonadosomatic index and serum hormone levels, upregulated estrogen receptor (er) and progesterone receptor (pr) gene transcription levels, and markedly affected ovarian metabolite levels. Combined exposure led to more adverse effects than single exposure. The data demonstrate that the Cu and Cd exposure can impair ovarian function and structure, with more pronounced adverse effects under Cu and Cd co-exposure. The Cu and Cd affect the metabolic pathways of nucleotides and amino acids, leading to ovarian damage. This study highlights the importance of considering combined toxicant exposure in aquatic toxicology research and provides insights into the potential mechanisms underlying heavy metal-induced reproductive toxicity in fish.

Sargassum polysaccharide inhibits inflammatory response in PCV2 infected-RAW264.7 cells by regulating histone acetylation.

Toxic inflammatory response is frequently introduced upon virus infection. In this study, RAW264.7 cells were infected with porcine circovirus type 2 (PCV2) and treated with Sargassum polysaccharide SP. It was found that PCV2 infection induced increased significant inflammation response represented with increased secretion of inflammatory cytokines, corresponding with promoted HAT activity, inhibited HDAC activity, elevated HDAC1 mRNA levels, and up-regulated acetylation levels of H3 and H4 in RAW264.7 cells. SP treatment significantly inhibited the increase of inflammatory cytokines, HAT activity and the acetylation of histones, but dramatically increased the HDAC activity and the expression of HDAC1. From these results, SP might be able to protect immune cells from virus induced damages through inhibiting the inflammatory responds by maintaining an equilibrium between the activity of HATs and HDACs which contributes to an appropriate level of histone acetylation.

Sophora subprosrate polysaccharide inhibited cytokine/chemokine secretion via suppression of histone acetylation modification and NF-κb activation in PCV2 infected swine alveolar macrophage.

In the present study, effect of Sophora subprosrate polysaccharide on PCV2 infection-induced inflammation and histone acetylation modification in swine alveolar macrophage 3D4/2 cells was described for the first time. The relationship between histone acetylation modifications and inflammation response was investigated. The results showed that PCV2 infection induced inflammation by promoting the secretion of TNF-α, IL-1ß, IL-6 and IL-10 in 3D4/2 cells. The production of TNF-α, IL-1ß and IL-6 and their mRNA expression levels markedly decreased while the level and mRNA expression of IL-10 were elevated when the cells were treated with Sophora subprosrate polysaccharide. The SSP also decreased the activity of HATs, histone H3 acetylation (Ac-H3) and histone H4 acetylation (Ac-H4), p65 phosphorylation (P-p65) in the cells infected with PCV2 while HDACs activity was down-regulated, which involved in the inhibitory effect of SSP on histone acetylation and NF-κB signaling pathways activation. Down-regulation of HAT1 mRNA expression and up-regulation of HDAC1 mRNA expression further support the inhibitory effect of SSP on histone acetylation. In conclusion, Sophora subprosrate polysaccharide antagonized inflammatory responses induced by PCV2, via mechanisms involved in histone acetylation and NF-κB signaling pathways.