Widespread application of anammox process has been primarily limited to the high sensitivity of anammox consortia to fluctuations of temperature. However, the metabolic acclimation of anammox consortia to decreased temperature remains unclear, which is the core of developing potential strategies for improving their low-temperature resistance. Here, we operated anammox reactors at 25 °C and 35 °C to explore the acclimation mechanism of anammox consortia in terms of metabolic responses and cross-feedings. Accordingly, we found that the adaptation of anammox consortia to ambient temperature (25 °C) was significantly linked to energy conservation strategy, resulting in decreased extracellular polymeric substance secretion, accumulation of ATP and amino acids. The expression patterns of cold shock proteins and core enzymes caused the apparent metabolic advantage of Candidatus Brocadia fulgida for acclimation to ambient temperature compared to other anammox species. Importantly, strengthened cross-feedings of amino acids, nitrite and glycine betaine benefited adaptation of anammox consortia to ambient temperature. Our work not only uncovers the temperature-adaptive mechanisms of anammox consortia, but also emphasizes the important role of metabolic cross-feeding in the temperature adaptation of microbial community.

Background: Shikonin, a natural naphthoquinone, is abundant in Chinese herb medicine Zicao (purple gromwell) and has a wide range of biological activities, especially for cancer. Shikonin and its analogues have been reported to induce cell-cycle arrest, but target information is still unclear. We hypothesized that shikonin, with a structure similar to that of quinone-type compounds, which are inhibitors of cell division cycle 25 (Cdc25) phosphatases, will have similar effects on Cdc25s. To test this hypothesis, the effects of shikonin on Cdc25s and cell-cycle progression were determined in this paper. Methods: The in vitro effects of shikonin and its analogues on Cdc25s were detected by fluorometric assay kit. The binding mode between shikonin and Cdc25B was modelled by molecular docking. The dephosphorylating level of cyclin-dependent kinase 1 (CDK1), a natural substrate of Cdc25B, was tested by Western blotting. The effect of shikonin on cell cycle progression was investigated by flow cytometry analysis. We also tested the anti-proliferation activity of shikonin on cancer cell lines by MTT assay. Moreover, in vivo anti-proliferation activity was tested in a mouse xenograft tumour model. Results: Shikonin and its analogues inhibited recombinant human Cdc25 A, B, and C phosphatase with IC₅₀ values ranging from 2.14 ± 0.21 to 13.45 ± 1.45 μM irreversibly. The molecular modelling results showed that shikonin bound to the inhibitor binding pocket of Cdc25B with a favourable binding mode through hydrophobic interactions and hydrogen bonds. In addition, an accumulation of the tyrosine 15-phosphorylated form of CDK1 was induced by shikonin in a concentration-dependent manner in vitro and in vivo. We also confirmed that shikonin showed an anti-proliferation effect on three cancer cell lines with IC₅₀ values ranging from 6.15 ± 0.46 to 9.56 ± 1.03 μM. Furthermore, shikonin showed a promising anti-proliferation effect on a K562 mouse xenograph tumour model. Conclusion: In this study, we provide evidence for how shikonin induces cell cycle arrest and functions as a Cdc25s inhibitor. It shows an anti-proliferation effect both in vitro and in vivo by mediating Cdc25s.

Naked carp ( Gymnocypris przewalskii ) is a second-grade animal under state protection of China. We report 16S rRNA gene amplicon analysis of the gut microbiota of Gymnocypris przewalskii . The three most abundant phyla are Tenericutes , Proteobacteria , and Fusobacteria , and the six most abundant genera are Aeromonas , Clostridium , Cetobacterium , Shewanella , Prochlorococcus , and Vibrio .

Climate-change-induced thermal stress poses a significant threat to cold-adapted aquatic species, particularly fish endemic to high-altitude ecosystems such as Gymnocypris eckloni, which is native to the Qinghai-Tibetan Plateau. To elucidate the molecular and metabolic mechanisms underlying their response to elevated temperatures, we integrated RNA-seq, miRNA-seq, and LC-MS-based metabolomic analyses of liver tissue from fish exposed to chronic thermal stress (HT) versus control (CT) conditions. Although no significant differences were observed in growth parameters, histopathological examination revealed structural damage under heat stress. Transcriptomic analysis identified widespread dysregulation of genes involved in energy metabolism, with significant downregulation of pathways related to amino acid, fatty acid, glucose, and oxidative phosphorylation. In contrast, upregulated DEGs were enriched in N-glycan biosynthesis, protein processing in the endoplasmic reticulum, and phagosome. Concomitant miRNA profiling revealed differentially expressed miRNAs, including miR-196a-5p, miR-132-3p, and miR-181b-5p, which were predicted to regulate key metabolic genes such as ugt1a1, pepck, and calr. Metabolomic analysis further demonstrated significant alterations in metabolic profiles, with glutathione metabolism, tryptophan metabolism, steroid hormone biosynthesis, and pyruvate metabolism emerging as central pathways in the heat stress response. Integrated multi-omics analysis confirmed coordinated regulation of these pathways, highlighting the critical role of glutathione and tryptophan, as well as disruptions in purine and energy metabolism. The DEMiR-DEG-DEM networks involving miR-196a-5p-pepck-PEP, miR-133a-3p-gne-UDP-GlcNAc, and miR-132-3p-ugt1a1-Bilirubin may play an important role in thermal stress. This study provided a new perspective on the molecular, regulatory, and metabolic adaptations of Gymnocypris eckloni to thermal stress, identifying potential biomarkers and regulatory networks that may inform conservation strategies for cold-water fish under global warming.

Many xenobiotic compounds can threaten human health and natural ecosystems. The ability to predict the level of human activities and identify major impact factors is crucial for the design of pollutant risk-reduction plans. In this study, a total of 25 volatile organic compounds (VOCs) including eight alkenes, six alkanes, and eleven aromatics were identified at 11 monitoring locations along the Huangshui River of the Tibetan Plateau. GC-MS analysis was applied to detect the concentrations of the VOCs. The results showed that the alkene, alkane, and aromatic concentrations in the sediment were significantly higher than in the water in all seasons (p < 0.001). The VOC concentrations in summer were significantly higher than in spring and winter (p < 0.01). In addition, several VOCs were found to surpass the national standard, i.e., bromoform reached 312.43 μg/L in water during the summer (the national standard is 100 μg/L), carbon tetrachloride was 209.58 μg/L (the national standard is 2 μg/L), and vinyl chloride was 10.99 μg/L (the national standard is 5 μg/L), which were all related to human activities. Principal component analysis (PCA) was used to comprehensively evaluate the water quality and the VOCs. The total organic carbon (TOC) was found to be responsible for the presence of the VOCs in the river, accounting for 77.93%, 81.97%, and 82.13% of the total variance in the datasets in spring, summer, and winter, respectively.