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An EMS (ethy methanesulfonate)-induced lethal etiolated (le) mutant obtained from the rice variety Zhongjian 100 was characterized by lethal etiolated phenotypes, with significantly reduced levels of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids. Additionally, the mutant displayed a significantly decreased number of chloroplast grana, along with irregular and less-stacked grana lamellae. The le mutant showed markedly diminished root length, root surface area, and root volume compared with the wild type. It also exhibited significantly lower catalase activity and total protein content, while peroxidase activity was significantly higher. Using the map-based cloning method, we successfully mapped the LE gene to a 48-kb interval between markers RM16107 and RM16110 on rice chromosome 3. A mutation (from T to C) was identified at nucleotide position 692 bp of LOC_Os03g59640 (ChlD), resulting in a change from leucine to proline. By crossing HM133 (a pale green mutant with a single-base substitution of A for G in exon 10 of ChlD subunit) with a heterozygous line of le (LEle), we obtained two plant lines heterozygous at both the LE and HM133 loci. Among 15 transgenic plants, 3 complementation lines displayed normal leaf color with significantly higher total chlorophyll, chlorophyll a, and chlorophyll b contents. The mutation in le led to a lethal etiolated phenotype, which has not been observed in other ChlD mutants. The mutation in the AAA+ domain of ChlD disrupted the interaction of ChlDle with ChlI as demonstrated by a yeast two-hybrid assay, leading to the loss of ChlD function and hindering chlorophyll synthesis and chloroplast development. Consequently, this disruption is responsible for the lethal etiolated phenotype in the mutant.

Objective: To investigate the chemical composition and anti-inflammatory mechanism of Coregonus peled oil (CPO). Methods: CPO was extracted by ultrasonic homogenization and its major chemical components were detected. In addition, its fatty acid (FA) composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Macrophage RAW264.7 cells were cultured as an inflammation model and stimulated with lipopolysaccharides (LPS). Cytotoxicity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The accumulation of succinate was detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). The concentration of nitric oxide (NO) and the activity of inducible nitric oxide synthase (iNOS) in the supernatant were measured by commercial kits. Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the supernatant. The expression levels of CD68, CD86, Arg1, CD206, YM1 and HIF-1α were detected by quantitative real-time polymerase chain reaction (qPCR), and their protein expression levels were determined by Western blotting. Results: The major chemical constituents of CPO were palmitoleic acid, oleic acid, eicosapntemacnioc acid (EPA), and docosahexaenoic acid (DHA). CPO significantly inhibited the production of NO, iNOS, IL-6, TNF-α, and IL-1β as well as their gene expression levels. CPO blocked NF-κB activation by inhibiting the degradation of inhibitor α of NF-κB (IκBα) and decreasing p65 nuclear translocation in LPS-induced RAW264.7 cells. In addition, CPO promoted macrophage polarization from M1 to M2 types by inhibiting the phosphorylation of signal transducer and activator of transcription 1 (STAT1). The content of succinate and the expression levels of hypoxia-inducible factor-1α (HIF-1α) gene and protein indicated that CPO could inhibit the production of IL-1β by inhibiting the accumulation of succinate. Conclusion: The anti-inflammatory mechanism of CPO may be due to the inhibition of the NF-κB, STAT1, and succinate/HIF-1α signaling pathways.

Objective: To investigate the effect and underlying mechanism of live and pasteurized Akkermansia muciniphila on serum uric acid levels and inflammation in hyperuricemic mice. Methods: An Institute of Cancer Research (ICR) mouse model of hyperuricemia was established by oral administration with potassium oxonate and hypoxanthine combined with dietary supplementation with 20% of yeast extract for three weeks. The mice in the treatment groups were gavaged with live and pasteurized Akkermansia muciniphila, separately. Blood and tissue samples were collected to measure serum uric acid concentration as well as liver xanthine oxidase activity and to analyze renal and intestinal pathology by hematoxylin and eosin (HE) staining. Results: Both live and pasteurized Akkermansia muciniphila could reduce the concentration of serum uric acid in mice to a certain extent, and down-regulate the activity and protein expression of hepatic xanthine oxidase (XOD), thereby reducing the production of uric acid in the liver. Histopathological analysis showed that both the kidney and intestinal tract of mice in the model group were damaged, including glomerular atrophy, inflammatory cell infiltration in renal interstitium, and shortened intestinal villi. Treatment with Akkermansia muciniphila alleviated these symptoms. Akkermansia muciniphila intervention could also down-regulate Toll-like receptors 4 (TLR4) and Caspase-1 in the kidney and intestine, thereby inhibiting the expression of interleukin (IL-1β) and effectively alleviating the inflammatory responses in mice. This study shows that Akkermansia muciniphila can be used to improve hyperuricemia in mice, and pasteurized Akkermansia muciniphila also exhibits the same effect. These findings can lay a theoretical basis for developing probiotics and probiotic-related products for improving hyperuricemia in the future.