Food additive sodium bisulfite induces intracellular imbalance of biothiols levels in NCM460 colonic cells to trigger intestinal inflammation in mice.

Sulfites and other preservatives are considered food additives to prevent pathogen growth in food, and they are generally regarded as safe since the late 1950s. However, the possible effects of sulfites on potential damage to host intestinal tissue remain largely unexplored. Given that endogenous sulfite mainly comes from the metabolism of biothiol, we attempted to clarify the relationship among biothiol levels, gut and food additives sulfite, including sodium bisulfite (NaHSO3), and the possible mechanism of sulfite affecting the intestine. In the present study, the NaHSO3 treatments markedly increased the homocysteine (Hcy) level but decreased the cysteine (Cys) level by promoting the expression of Hcy synthase and inhibiting the activities of cystathionine ß-synthase and cystathionine γ-lyase in NCM460 cells. The level of methionine (Met) was not significantly changed, but NaHSO3 promoted ROS-mediated NF-κB signaling pathway, and increased the expressions of proinflammatory cytokines by regulating the levels of Hcy and Cys in NCM460 cells. Vitamin B6 (VB6) supplementation successfully ameliorated NaHSO3-induced damage in NCM460 cells and the colon of Balb/c mice. Altogether, our study provided valuable insights into the safety evaluation of food preservatives. Besides, VB6 could be used as a promising candidate in novel therapies for sodium bisulfite-induced intestinal inflammation.

Omics Analyses of Gut Microbiota in a Circadian Rhythm Disorder Mouse Model Fed with Oolong Tea Polyphenols.

Microbiome has been revealed as a key element involved in maintaining the circadian rhythms. Oolong tea polyphenols (OTP) has been shown to have potential prebiotic activity. Therefore, this study focused on the regulation mechanisms of OTP on host circadian rhythms. After 8 weeks of OTP administration, a large expansion in the relative abundance of Bacteroidetes with a decrease in Firmicutes was observed, which reflected the positive modulatory effect of OTP on gut flora. In addition, Kyoto Encyclopedia of Genes and Genomes pathways of ATP-binding cassette transporters, two-component system, and the biosynthesis of amino acids enriched the most differentially expressed genes after OTP treatment. Of the differentially expressed proteins identified, most were related to metabolism, genetic information processing, and environmental information processing. It underscores the ability of OTP to regulate circadian rhythm by enhancing beneficial intestinal microbiota and affecting metabolic pathways, contributing to the improvement of host microecology.

A ferritin from Dendrorhynchus zhejiangensis with heavy metals detoxification activity.

Ferritin, an iron homeostasis protein, has important functions in transition and storage of toxic metal ions. In this study, the full-length cDNA of ferritin was isolated from Dendrorhynchus zhejiangensis by cDNA library and RACE approaches. The higher similarity and conserved motifs for ferritin were also identified in worm counterparts, indicating that it belonged to a new member of ferritin family. The temporal expression of worm ferritin in haemocytes was analyzed by RT-PCR, and revealed the ferritin could be induced by Cd(2+), Pb(2+) and Fe(2+). The heavy metal binding activity of recombinant ferritin was further elucidated by atomic force microscopy (AFM). It was observed that the ferritin protein could form a chain of beads with different size against three metals exposure, and the largest one with 35~40 nm in height was identified in the Cd(2+) challenge group. Our results indicated that worm ferritin was a promising candidate for heavy metals detoxification.