Heat stress-induced dysbiosis of the gut microbiota impairs spermatogenesis by regulating secondary bile acid metabolism in the gut.

Heat stress (HS) poses a substantial challenge to livestock. Studies have demonstrated that HS reduces fertility and leads to gut microbiota dysbiosis in bulls. However, the impact of the gut microbiota on fertility in bulls during HS is still unclear. Our research revealed that HS exposure decreased semen quality in bulls, and fecal microbiota transplantation (FMT) from heat-stressed bulls to recipient mice resulted in a significant decrease in number of testicular germ cells and epididymal sperm. Untargeted metabolomics methodology and 16S rDNA sequencing conjoint analysis revealed that Akkermansia muciniphila (A. muciniphila) seemed to be a key bacterial regulator of spermatogenesis after HS exposure. Moreover, the research indicated that A. muciniphila regulated secondary bile acid metabolism by promoting the colonization of bile salt hydrolase (BSH)-metabolizing bacteria, leading to increase of retinol absorption in the host gut and subsequently elevation of testicular retinoic acid level, thereby improving spermatogenesis. This study sheds light on the relationship between HS-induced microbiota dysbiosis and spermatogenesis, offering a potential therapeutic approach for addressing bull spermatogenic dysfunction triggered by HS exposure.

Gut-Derived Exosomes Mediate the Microbiota Dysbiosis-Induced Spermatogenesis Impairment by Targeting Meioc in Mice.

Diseases like obesity and intestinal inflammation diseases are accompanied by dysbiosis of the gut microbiota (DSGM), which leads to various complications, including systemic metabolic disorders. DSGM reportedly impairs the fertility of male mice; however, the regulatory mechanism is unclear. Exosomes are molecular mediators of intercellular communication, but the regulation of spermatogenesis by non-reproductive tissue-originated exosomes remains unknown. The present study shows that DSGM altered the miRNA expression profile of mouse circulating exosomes and impaired spermatogenesis. Moreover, the single-cell sequencing results indicate that circulating exosomes from mice with DSGM impaired spermatogenesis, while circulating exosomes from wild mice improved spermatogenesis by promoting meiosis. Further study demonstrates that DSGM leads to abnormal upregulation of miR-211-5p in gut-derived circulating exosomes, which inhibited the expression of meiosis-specific with coiled-coil domain (Meioc) in the testes and impaired spermatogenesis by disturbing meiosis process. In summary, this study defines the important role of gut-derived exosomes in connecting the "gut-testis" axis.

YTHDF2 as a Mediator in BDNF-Induced Proliferation of Porcine Follicular Granulosa Cells.

In female mammals, the proliferation and apoptosis of granulosa cells (GCs) are critical in determining the fate of follicles and are influenced by various factors, including brain-derived neurotrophic factor (BDNF). Previous research has shown that BDNF primarily regulates GC proliferation through the PI3K/AKT, NF-kB, and CREB tumour pathways; however, the role of other molecular mechanisms in mediating BDNF-induced GC proliferation remains unclear. In this study, we investigated the involvement of the m6A reader YTH domain-containing family member 2 (YTHDF2) in BDNF-stimulated GC proliferation and its underlying mechanism. GCs were cultured in DMEM medium supplemented with varying BDNF concentrations (0, 10, 30, 75, and 150 ng/mL) for 24 h. The viability, number, and cell cycle of GCs were assessed using the CCK-8 assay, cell counting, and flow cytometry, respectively. Further exploration into YTHDF2's role in BDNF-stimulated GC proliferation was conducted using RT-qPCR, Western blotting, and sequencing. Our findings indicate that YTHDF2 mediates the effect of BDNF on GC proliferation. Additionally, this study suggests for the first time that BDNF promotes YTHDF2 expression by increasing the phosphorylation level of the ERK1/2 signalling pathway. This study offers a new perspective and foundation for further elucidating the mechanism by which BDNF regulates GC proliferation.

Follicular fluid exosomes inhibit expression of BTG2 and promote glucose uptake in granulosa cells by delivering miR-21-5p.

Glucose metabolism in granulosa cells (GCs) is essential for follicle development and oocyte maturation. Porcine follicular fluid exosomes promote the proliferation of porcine GCs and the synthesis of steroid hormones. However, their role in regulating glucose uptake in GCs is unclear. The objective of this study was to elucidate the effects of porcine follicular fluid exosomes on glucose uptake in porcine GCs and the intrinsic mechanisms involved. First, transcriptome sequencing revealed that glucose metabolism-related pathways were altered in GCs treated with follicular fluid exosomes. Next, in vitro culture experiments showed that glucose uptake was increased and the IRS1/AKT signaling pathway was activated in GCs after treatment with follicular fluid exosomes. Finally, miRNA sequencing of follicular fluid exosomes revealed that miR-21-5p was the most abundant miRNA. Subsequent investigations indicated that miR-21-5p promoted glucose uptake in GCs by targeting BTG2, which activated the IRS1/AKT signaling pathway. In conclusion, the findings of this study indicate that porcine follicular fluid exosomes promote glucose uptake in porcine GCs by delivering miR-21-5p, which inhibits the expression of BTG2, activating the IRS1/AKT signaling pathway.

lnc RNA LOC102163816 Promotes Proliferation of Porcine Follicular Granulosa Cells Via miR-455-3p/PTK2B/PI3K/AKT Pathway.

The proliferation and differentiation of granulosa cells (GCs) is a crucial process in follicular development. However, the molecular regulatory mechanism of follicular proliferation and differentiation of GCs needs further research. Studies have reported that follicular fluid exosomes are involved in regulation of proliferation of GCs, but the specific mechanism is unclear. This study demonstrated that LOC102163816 is upregulated in porcine GCs treated with follicular fluid exosomes. Further study defined LOC102163816 to be a novel long noncoding RNA that is highly homologous to human metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and enriched in porcine follicular fluid exosomes. We have speculated that LOC102163816 might have a cell-proliferative effect similar to that of MALAT1. We found that overexpression of LOC102163816 promoted transition from the G1 phase to the S phase of the cell cycle, thereby promoting proliferation of GCs. To explore the specific mechanism underlying this promotion of proliferation, miRNA sequencing was performed after overexpression of LOC102163816. Our results showed that LOC102163816 sponged miR-455-3p, promoting expression of protein tyrosine kinase 2 beta (PTK2B), thereby activating the PI3K/AKT signaling pathway to regulate proliferation of porcine follicular GCs. These findings provide useful insights into follicular development.

Oxygen vacancies-rich Cu-W18O49 nanorods supported on reduced graphene oxide for electrochemical reduction ofN2to NH3.

High-performance nitrogen fixation is severely limited by the efficiency and selectivity of a catalyst of electrochemical nitrogen reduction reaction (NRR) under ambient conditions. Here, the RGO/WOCu (reduced graphene oxide and Cu-doping W18O49) composite catalysts with abundant oxygen vacancies are prepared by the hydrothermal method. The obtained RGO/WOCu achieves an enhanced NRR performance (NH3 yield rate:11.4 µg h-1 mgcat-1, Faradaic efficiency: 4.4%) at -0.6 V (vs. RHE) in 0.1 mol L-1 Na2SO4 solution. Furthermore, the NRR performance of the RGO/WOCu still keeps at 95% after four cycles, demonstrating its excellent stability. The Cu+-doping increases the concentration of oxygen vacancies, which is conducive to the adsorption and activation of N2. Meanwhile, the introduction of RGO further improves the electrical conductivity and reaction kinetics of the RGO/WOCu due to the high specific surface area and conductivity. This work provides a simple and effective method for efficient electrochemical reduction ofN2.

Paclobutrazol Ameliorates Low-Light-Induced Damage by Improving Photosynthesis, Antioxidant Defense System, and Regulating Hormone Levels in Tall Fescue.

Paclobutrazol (PBZ) is a plant-growth regulator (PGR) in the triazole family that enhances plant tolerance to environmental stresses. Low-light (LL) intensity is a critical factor adversely affecting the growth of tall fescue (Festuca arundinacea Schreb.). Therefore, in this study, tall fescue seedlings were treated with PBZ under control and LL conditions to investigate the effects of PBZ on enhancing LL stress resistance by regulating the growth, photosynthesis, oxidative defense, and hormone levels. Our results reveal that LL stress reduced the total biomass, chlorophyll (Chl) content, photosynthetic capacity, and photochemical efficiency of photosystem II (PSII) but increased the membrane lipid peroxidation level and reactive oxygen species (ROS) generation. However, the application of PBZ increased the photosynthetic pigment contents, net photosynthetic rate (Pn), maximum quantum yield of PSII photochemistry (Fv/Fm), ribulose-1,5-bisphosphate carboxylase (RuBisCO) activity, and starch content. In addition, PBZ treatment activated the antioxidant enzyme activities, antioxidants contents, ascorbate acid-glutathione (AsA-GSH) cycle, and related gene expression, lessening the ROS burst (H2O2 and O2∙-). However, the gibberellic acid (GA) anabolism was remarkably decreased by PBZ treatment under LL stress, downregulating the transcript levels of kaurene oxidase (KO), kaurenoic acid oxidase (KAO), and GA 20-oxidases (GA20ox). At the same time, PBZ treatment up-regulated 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, significantly increasing the endogenous abscisic acid (ABA) concentration under LL stress. Thus, our study revealed that PBZ improves the antioxidation and photosynthetic capacity, meanwhile increasing the ABA concentration and decreasing GA concentration, which ultimately enhances the LL stress tolerance in tall fescue.

N-doping TiO2 hollow microspheres with abundant oxygen vacancies for highly photocatalytic nitrogen fixation.

Photocatalytic fixation of nitrogen to ammonia (NH3) is a green but low-efficiency technology due to the high recombination of photo-generated carriers and poor light absorption of photocatalysts. Generally, the adsorption capacity for N2 and the band position of TiO2 are responsible for bandgap, light-adsorption, and the separation of photocarriers. Therefore, they play crucial roles to improve catalytic activity. Herein, N-doping TiO2 hollow microspheres (NTO-0.5) with oxygen vacancies were synthesized via a hydrothermal method using phenolic resin microsphere as a template. The obtained NTO-0.5 achieves an impressive ammonia yield of 80.09 µmol gcat-1h-1. Oxygen vacancies of NTO-0.5 were confirmed by ESR, Raman, XPS, Zeta potential, and H2O2 treatment for reducing oxygen vacancies. The ammonia yield of NTO-0.5 decreases to 34.78 µmol gcat-1h-1 after reducing oxygen vacancies by H2O2 treatment, which demonstrates the importance of oxygen vacancies. The oxygen vacancies narrow the bandgap from 3.18 eV to 2.83 eV and impede the recombination of photo-generated carriers. The hollow microspheres structure is conducive to light absorption and utilization. Therefore, the synergistic effect between the oxygen vacancies and the hollow microspheres structure boosts the efficiency of photocatalytic nitrogen fixation. After four cycles, the ammonia production yield still maintains at 76.52 µmol gcat-1h-1, meaning high stability. This work provides a new insight into the construction of catalysts with oxygen vacancies to enhance photocatalytic nitrogen fixation performance.

2-Methyl Nonyl Ketone From Houttuynia Cordata Thunb Alleviates LPS-Induced Inflammatory Response and Oxidative Stress in Bovine Mammary Epithelial Cells.

Mastitis is one of the most common diseases in dairy cows, causing huge economic losses to the dairy industry every year. Houttuynia Cordata Thunb ( H.cordata ) is a traditional Chinese herbal medicine that is widely used in clinical treatment. However, the therapeutic effect of 2-methyl nonyl ketone (MNK), the main volatile oil component in the aqueous vapor extract of H. cordata, on mastitis has been less studied. The purpose of this study was to investigate the protective effect and mechanism of MNK against lipopolysaccharide (LPS)-induced mastitis in vitro. The results showed that MNK pretreatment of the bovine mammary epithelial cell line (MAC-T) enhanced cell viability and inhibited LPS-induced reactive oxygen species (ROS) production and inflammatory response. MNK reduced the production of pro-inflammatory cytokines such as interleukin (IL) and tumor necrosis factor-α (TNF-α) by repressing LPS-induced activation of Toll-like receptor 4-nuclear factor-κB (TLR4-NF-κB) signaling pathway. In addition, MNK protected cells from inflammatory responses by blocking the downstream signaling of inflammatory factors. MNK also induced Heme Oxygenase-1 ( HO-1 ) production by Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway through AKT and extracellular signal-regulated kinase (ERK) pathways, thereby reducing LPS-induced oxidative damage for MAC-T cells. In conclusion, MNK played a protective role against LPS-induced cell injury. This provides a theoretical basis for the research and development of MNK as a novel therapeutic agent for mastitis.