Biology

Dynamic developmental states of follicles are regarded to be determinants of sexual maturation in fish ovaries. However, it is still a challenge to identify the critical points at which the developmental processes of different types of follicles interact and affect the ovarian development. In this study, four subtypes of the primary follicle (PF) in the ovarian folliculogenesis of zebrafish, i.e., the so-called PF-i, PF-ii, PF-iii, and PF-iv, are first identified by discontinuous NaCl-Percoll gradient centrifugation, as well as their respective morphological features. Then, for the four subtypes of PFs, stage-specific comparative analysis is employed to identify the differentially expressed genes and the differentially methylated regions, which have been validated to be significantly enriched in biological processes encompassing ribosomal biogenesis, meiotic progression, transcriptional regulation, and mitochondrial respiration. Results from transcriptional analysis further demonstrate significant changes in the expression profiles at different developmental stages from the PF-ii to the PF-iii. By molecular biology identification, it is shown that the enhancement of Notch and mTOR pathways can significantly regulate the ovarian development through the pacing effect of primary follicles. Clearly, all these uncovered results could provide a deeper understanding of the initial regulation of ovarian maturation, as well as a new multidisciplinary analytic tool to study follicle candidate regulators in the developmental process of other fish.

Dysregulated macrophage polarization is associated with various diseases, including sepsis, atherosclerosis, and fibrotic diseases. While taurine is known to exert immunomodulatory effects, its mechanism in regulating M1 macrophage polarization and interleukin-1β (IL-1β) production remains incompletely understood. This study aimed to elucidate the role of taurine in modulating macrophage immunometabolism and inflammatory signaling. Using thioglycolate-elicited peritoneal macrophages and macrophage cell lines, we assessed taurine’s impact on lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced M1 polarization through metabolomics and a range of molecular biology techniques. Pharmacological manipulation of the JAK1/2-STAT1 pathway and an LPS-induced murine sepsis model were used for mechanistic and therapeutic validation. Our results demonstrate that taurine significantly suppressed M1 polarization. Metabolomic profiling uniquely identified a marked increase in intracellular spermine as a key metabolic alteration induced by taurine. This increased spermine subsequently inhibited JAK1/2-STAT1 activation, leading to reduced IL-1β release. In mice, taurine alleviated systemic inflammation, reduced pathological damage in multiple organs, and decreased intestinal M1 macrophage infiltration. These findings establish a novel mechanism where taurine attenuates M1 polarization and IL-1β production through metabolically driven spermine accumulation and subsequent JAK1/2-STAT1 suppression, highlighting its therapeutic potential for inflammatory diseases.

Continuous cropping affects soil health, microbial diversity, and organic matter dynamics, but its long-term impacts on soils under Aralia continentalis Kitag. (a medicinally important Northeast China-native plant) remain unclear. This study evaluated effects of 2-, 6-, and 12-year continuous cropping on soil microbial communities, physicochemical properties, and dissolved organic matter (DOM) of bulk soils, and elucidated links between cropping duration and soil health indicators. Results showed that key physicochemical properties (total organic carbon, TOC) and available nutrients (available nitrogen, AN; available phosphorus, AP; available potassium, AK) declined with cropping duration: AN, AP, and AK decreased from 75.24 ± 1.2, 16.39 ± 0.05, and 104.8 ± 0.27 mg·kg⁻¹ (2 years) to 63.47 ± 1.53, 13.38 ± 0.16, and 88.71 ± 0.94 mg·kg⁻¹ (12 years), respectively. Microbial diversity increased initially but stabilized after 6 years, with communities shifting from copiotrophic taxa (e.g., Proteobacteria) to oligotrophic taxa (e.g., Acidobacteria). Partial Least Squares Path Modeling (PLS-PM) revealed strong positive correlations between dissolved/organic carbon (DOC/TOC) and microbial diversity, highlighting organic matter’s role in sustaining microbial richness. UV-visible and 3D fluorescence spectroscopy indices correlated significantly with microbial diversity, confirming their utility for monitoring DOM quality and microbial dynamics. This study clarifies dynamic interactions between soil properties, microbial diversity, and organic matter under continuous cropping, providing insights for sustainable cultivation of A. continentalis.