Remediation of Cd-As-Ni co-contaminated soil by extracellular polymeric substances from Bacillus subtilis: Dynamic improvements of soil properties and ecotoxicity.

As the primary reservoir of heavy metals in nature, soil is highly susceptible to significant co-contamination with Cd-As-Ni. In current study, extracellular polymeric substances (EPS) from Bacillus subtilis were utilized as a novel improver to simultaneously enhance soil property and restrain ecotoxicity in Cd-As-Ni co-contaminated soil. Our findings revealed that EPS effectively bound and immobilized free Cd, As, and Ni in soil and decreased 49.73 % of soil available Cd, 79.16 % of As and 77.87 % of Ni contents by increasing soil pH, soil organic matter and cation exchange capacity. The EPS was also found to inhibit the Cd-As-Ni induced ecotoxicity in Caenorhabditis elegans by increasing the activities of antioxidant enzymes including superoxide dismutase, glutathione, and catalase. The remediation of EPS showed progressive improvement over time, and maintained a lasting effect after achieving peak efficiency. Our results might provide a new perspective on the potential of EPS in remediation of soil heavy metal pollution and the development and utilization of microbial biomass resources in a wider range.

The ROS Mediates MCUb in Mitochondria-Regulated Apoptosis of TM4 Cells Induced by Titanium Dioxide Nanoparticles.

Titanium dioxide nanoparticles (TiO2 NPs) can cause mitochondrial apoptosis of TM4 cells associated with reactive oxygen species (ROS) accumulation and Ca2+ overload, but the relations among these processes remain unclear. This study aimed to evaluate whether the accumulation of ROS caused by TiO2 NPs inhibits MCUb expression, leading to mitochondrial calcium overload and subsequent cell apoptosis through the mitochondrial pathway. TM4 cells were exposed to different concentrations of TiO2 NPs (0, 25, 50, 75, 100 µg/mL) for 24 h. We assessed cell viability, ROS level, MCUb and VDAC1 expression, mitochondrial and cytoplasmic Ca2+ levels, mitochondrial membrane potential (MMP), apoptosis rate, and key proteins related to mitochondrial apoptosis (Bcl-2, Bax, Caspase 3, Caspase 9, p53 and Cyt c). Additionally, the effect of N-acetylcysteine (NAC) on MCUb expression, calcium homeostasis, and cell apoptosis was evaluated. Compared to control group, TiO2 NPs significantly increased ROS level, downregulated MCUb expression, elevated Ca2+ levels in mitochondria and cytoplasm, and enhanced mitochondria-regulated apoptosis, starting from the 50 µg/mL TiO2 NPs group. However, NAC significantly increased MCUb expression, attenuated Ca2+ levels in mitochondria and cytoplasm, and reduced mitochondria-related apoptosis. In conclusion, TiO2 NPs induced ROS accumulation, which inhibited the expression of MCUb. The decreased MCUb level led to Ca2+ overload in mitochondria, causing TM4 cell apoptosis via the mitochondrial pathway. This research elucidates, for the first time, the role of MCUb and its relation with ROS in apoptosis of TM4 cells induced by TiO2 NPs, which supplementing the molecular mechanism of cell apoptosis caused by TiO2 NPs.

Study on the mechanisms of defective spermatogenesis induced by TiO2 NPs based on 3D blood-testis barrier microfluidic chip.

Titanium dioxide nanoparticles (TiO2 NPs) can reduce sperm number, but the mechanisms of defective spermatogenesis induced by TiO2 NPs have not been studied through cell-cell interactions at present. A kind of biomimetic three-dimensional blood-testis barrier microfluidic chip capable of intercellular communication was constructed with soft lithography techniques, including Sertoli cell (TM4), spermatogonia (GC-1) and vascular endothelial cell units, to study the mechanisms of TiO2 NPs-induced defective spermatogenesis. TM4 and GC-1 cells cultured in TiO2 NPs exposure and control chips were collected for transcriptomics and metabonomics analysis, and key proteins and metabolites in changed biological processes were validated. In TM4 cells, TiO2 NPs suppressed glucose metabolism, especially lactate production, which reduced energy substrate supply for spermatogenesis. TiO2 NPs also decreased the levels of key proteins and metabolites of lactate production. In GC-1 cells, TiO2 NPs disturbed chemokine signaling pathways regulating cell proliferation and interfered with glutathione metabolism. The Cxcl13, Stat3 and p-Stat3 levels and cell proliferation rate were decreased, and the GSR, GPX4 and GSH contents were increased in GC-1 cells in chips under TiO2 NPs treatment. The decrease in energy substrate supply for spermatogenesis and inhibition of spermatogonia proliferation could be the main mechanisms of defective spermatogenesis induced by TiO2 NPs.

The status and influencing factors of lung ventilation function in employees exposed to dust in enterprises of the XPCC, China.

Background: Occupational health is closely related to harmful factors in the workplace. Dust is the primary contributing factor causing impaired lung ventilation function among employees with dust exposure, and their lung ventilation function may also be influenced by other factors. We aimed at assessing the status and influencing factors of lung ventilation function among employees exposed to dust in the enterprises of the Eighth Division located in the Xinjiang Production and Construction Corps (XPCC), China. Methods: Employees exposed to dust in enterprises of the Eighth Division located in the XPCC in 2023 were selected as the subjects of this cross-sectional study. Their lung ventilation function indicators were extracted from health examination records, and an on-site electronic questionnaire survey was conducted among them. Binary logistic regression analyses were conducted to evaluate the factors influencing lung ventilation function. Results: According to the fixed value criteria, the abnormal rates of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC were 31.6, 1.4, and 0.4%, respectively. The lower limit of normal (LLN) criteria could overestimate the rate of abnormal lung ventilation function. Several factors were related to impaired lung ventilation function, including gender, age, education level, marital status, body mass index (BMI), smoking status, physical activity, the type of dust, industry, enterprise scale, occupation, length of service, working shift, monthly income, and respiratory protection. Conclusions: A relatively low abnormal rate of lung ventilation function was observed among employees exposed to dust in enterprises of the Eighth Division, XPCC, and their lung ventilation function was associated with various factors. Effective measures should be taken urgently to reduce the effects of adverse factors on lung ventilation function, thereby further protecting the health of the occupational population.

Titanium dioxide nanoparticles induce apoptosis through ROS-Ca2+-p38/AKT/mTOR pathway in TM4 cells.

Titanium dioxide nanoparticles (TiO2 NPs) can cause apoptosis in TM4 cells; however, the underlying mechanism has not been entirely elucidated. The purpose of this study was to investigate the effects of TiO2 NPs on ROS, Ca2+ level, p38/AKT/mTOR pathway, and apoptosis in TM4 cells and to evaluate the role of Ca2+ in p38/AKT/mTOR pathway and apoptosis. After exposure to different concentrations (0, 50, 100, 150, and 200 µg/mL) of TiO2 NPs for 24 h, cell viability, ROS, Ca2+ level, Ca2+-ATPase activity, p38/AKT/mTOR pathway-related proteins, apoptosis rate, and apoptosis-related proteins (Bax, Bcl-2, Caspase 3, Caspase 9, and p53) were detected. The ROS scavenger NAC was used to determine the effect of ROS on Ca2+ level. The Ca2+ chelator BAPTA-AM was used to evaluate the role of Ca2+ in p38/AKT/mTOR pathway and apoptosis. TiO2 NPs significantly inhibited cell viability, increased ROS level, and elevated Ca2+ level while suppressing Ca2+-ATPase activity. TiO2 NPs regulated the p38/AKT/mTOR pathway via increasing p-p38 level and decreasing p-AKT and p-mTOR levels. TiO2 NPs significantly enhanced the apoptosis. NAC attenuated Ca2+ overload and reduction in Ca2+-ATPase activity caused by TiO2 NPs. BAPTA-AM alleviated TiO2 NPs-induced abnormal expression of p38/AKT/mTOR pathway-related proteins. BAPTA-AM assuaged the apoptosis caused by TiO2 NPs. Altogether, this study revealed that TiO2 NPs elevated intracellular Ca2+ level through ROS accumulation. Subsequently, the heightened intracellular Ca2+ level was observed to exert regulation over the p38/AKT/mTOR pathway, ultimately culminating in apoptosis. These results provides a complementary understanding to the mechanism of TiO2 NPs-induced apoptosis in TM4 cells.

Titanium Dioxide Nanoparticles Induce Cell Cycle Arrest and Apoptosis through Inhibiting PI3K/AKT/mTOR Pathway in Spermatogonia.

Titanium dioxide nanoparticles (TiO2 NPs) can result in the reduction of sperm numbers, but the mechanisms have not been well elucidated. The purpose of this study was to investigate the effects of TiO2 NPs on cell cycle and apoptosis in spermatogonia and to explore the role of PI3K/AKT/mTOR signaling pathway in this process. The mouse spermatogonia cell line (GC-1) was treated with TiO2 NPs at different concentrations (0, 25, 50, 75 and 100 µg/mL) for 24 h to detect cell viability, cell cycle, apoptosis, and key proteins related to cell cycle and PI3K/AKT/mTOR signaling pathway. The agonist (IGF-1) and inhibitor (LY294002) of PI3K were used to verify the role of PI3K/AKT/mTOR signaling pathway in cell cycle and apoptosis. TiO2 NPs significantly inhibited cell proliferation, induced cell cycle arrest at G0/G1 phase and resulted in apoptosis. TiO2 NPs downregulated the levels of cyclin-dependent kinases (CDKs) and cyclins, including CDK4, CDK2, Cyclin D1 and Cyclin E1, while upregulated the levels of p21 and p53 proteins. Furthermore, TiO2 NPs inhibited the PI3K/AKT/mTOR signaling pathway by decreasing the levels of p-PI3K, p-AKT and p-mTOR. IGF-1 reversed the G0/G1 phase arrest and apoptosis caused by TiO2 NPs. However, LY294002 aggravated the G0/G1 phase arrest and apoptosis resulting from TiO2 NPs. Collectively, TiO2 NPs induced cell cycle arrest at G0/G1 phase and apoptosis through inhibiting the activation of PI3K/AKT/mTOR pathway, which could be the main reason for the reduction in sperm numbers caused by TiO2 NPs.

Optimization of Triterpene Yield from Ganoderma atrum HBSD Z19 (Agaricomycetes) by Optimization of Medium Components and Evaluation of Bioactivity Under Simulated Gastrointestinal Digestion In Vitro.

The intracellular triterpene yield from Ganoderma atrum was enhanced by optimization based on single-factor experiments, Plackett-Burman experimental design (PBED) and response surface methodology (RSM) under liquid fermentation conditions. The optimal medium composition (g·L-1) was glucose (46.0), bean cake powder (30.2), KH2PO4 (2.0), CaCl2 (3.0), MgSO4 (1.5), FeSO4 (0.2), and pH 6.0. Under the optimal conditions, the highest triterpene yield of 0.527 g·L-1 was obtained, which was 4.705-fold higher than before optimization. The fermented powder that was collected from the optimal medium was subjected to simulated gastrointestinal digestion, with differences resulting from extraction in different digestive juices (purified water, simulated gastric digestive juice, simulated gastrointestinal digestive juice). The content of triterpenes and polysaccharides increased, except for total phenol content. In terms of the antioxidant activity, the 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH+⋅) scavenging activity gradually decreased whereas the 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+⋅) scavenging activity first decreased and then increased. In terms of enzyme viability, the activity of α-amylase (α-AL) and α-glucosidase (α-GC) in the digestive juices decreased dramatically. The main bioactive components of G. atrum and their bioactivity in digestive juices were evaluated, providing a reference for the effective use of fermented power from G. atrum.

Transcriptome analysis revealing molecular mechanisms of enhanced pigment yield by succinic acid and fluconazole.

This study aimed to elucidate the molecular mechanisms through which succinic acid and fluconazole stimulate Monascus pigment biosynthesis under liquid fermentation conditions. The pigment yield was significantly improved by adding 0.35 g·L-1 succinic acid or 1.5 g·L-1 fluconazole. Transcriptome sequencing and RT-qPCR confirmation were performed to reveal transcriptome changes. The results indicated that the addition of succinic acid significantly decreased mRNA expression of genes involved in fatty acid biosynthesis while increasing expression of genes involved in pyruvate metabolism. Fluconazole significantly down-regulated transcripts involved in branched-chain amino acid metabolism, fatty acid metabolism, glycolysis/gluconeogenesis, and pyruvate metabolism, as well as the generation of acetyl-CoA for pigment biosynthesis. On the other hand, nitrogen metabolism and lysine degradation pathways were significantly enriched, which could stimulate the generation of acetyl-CoA. Therefore, the mechanism for enhancing pigment yield may be attributed to the competitive regulation of metabolic pathways toward acetyl-CoA biosynthesis. Additionally, up-regulation of some different key genes in the presence of fluconazole or succinic acid was involved in improving pigment production. This study deepens the theoretical understanding for enhancing pigment biosynthesis and provides a few potential approaches for improving pigment yield.

Human invariant natural killer T cells promote tolerance by preferential apoptosis induction of conventional dendritic cells.

Graft-versus-host disease (GvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. We recently showed in murine studies and in vitro human models that adoptively transferred invariant natural killer T (iNKT) cells protect from GvHD and promote graft-versus-leukemia effects. The cellular mechanisms underlying GvHD prevention by iNKT cells in humans, however, remain unknown. In order to study relevant cellular interactions, dendritic cells (DC) were either generated from monocytes or isolated directly from blood of healthy donors or GvHD patients and co-cultured in a mixed lymphocyte reaction (MLR) with T cells obtained from healthy donors or transplantation bags. Addition of culture-expanded iNKT cells to the MLR-induced DC apoptosis in a cell contact-dependent manner, thereby preventing T-cell activation and proliferation. Annexin V/propidium iodide staining and image stream assays showed that CD4+CD8-, CD4-CD8+ and double negative iNKT cells are similarly able to induce DC apoptosis. Further MLR assays revealed that conventional DC (cDC) but not plasmacytoid DC (pDC) could induce alloreactive T-cell activation and proliferation. Interestingly, cDC were also more susceptible to apoptosis induced by iNKT cells, which correlates with their higher CD1d expression, leading to a bias in favor of pDC. Remarkably, these results could also be observed in GvHD patients. We propose a new mechanism how ex vivo expanded human iNKT cells prevent alloreactivity of T cells. iNKT cells modulate T-cell responses by selective apoptosis of DC subsets, resulting in suppression of T-cell activation and proliferation while enabling beneficial immune responses through pDC.