Mitochondrial DNA Stress-Mediated Health Risk to Dibutyl Phthalate Contamination on Zebrafish (Danio rerio) at Early Life Stage.

Plastics contaminations are found globally and fit the exposure profile of the planetary boundary threat. The plasticizer of dibutyl phthalate (DBP) leaching has occurred and poses a great threat to human health and the ecosystem for decades, and its toxic mechanism needs further comprehensive elucidation. In this study, environmentally relevant levels of DBP were used for exposure, and the developmental process, oxidative stress, mitochondrial ultrastructure and function, mitochondrial DNA (mtDNA) instability and release, and mtDNA-cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway with inflammatory responses were measured in zebrafish at early life stage. Results showed that DBP exposure caused developmental impairments of heart rate, hatching rate, body length, and mortality in zebrafish embryo. Additionally, the elevated oxidative stress damaged mitochondrial ultrastructure and function and induced oxidative damage to the mtDNA with mutations and instability of replication, transcription, and DNA methylation. The stressed mtDNA leaked into the cytosol and activated the cGAS-STING signaling pathway and inflammation, which were ameliorated by co-treatment with DBP and mitochondrial reactive oxygen species (ROS) scavenger, inhibitors of cGAS or STING. Furthermore, the larval results suggest that DBP-induced mitochondrial toxicity of energy disorder and inflammation were involved in the developmental defects of impaired swimming capability. These results enhance the interpretation of mtDNA stress-mediated health risk to environmental contaminants and contribute to the scrutiny of mitochondrial toxicants.

Dibutyl phthalate exposure induced mitochondria-dependent ferroptosis by enhancing VDAC2 in zebrafish ZF4 cells.

Dibutyl phthalate (DBP) contamination has raised global concern for decades, while its health risk with toxic mechanisms requires further elaboration. This study used zebrafish ZF4 cells to investigate the toxicity of ferroptosis with underlying mechanisms in response to DBP exposure. Results showed that DBP induced ferroptosis, characterized by accumulation of ferrous iron, lipid peroxidation, and decrease of glutathione peroxidase 4 levels in a time-dependent manner, subsequently reduced cell viability. Transcriptome analysis revealed that voltage-dependent anion-selective channel (VDAC) in mitochondrial outer membrane was upregulated in ferroptosis signaling pathways. Protecting mitochondria with a VDAC2 inhibitor or siRNAs attenuated the accumulation of mitochondrial superoxide and lipid peroxides, the opening of mitochondrial permeability transition pore (mPTP), and the overload of iron levels, suggesting VDAC2 oligomerization mediated the influx of iron into mitochondria that is predominant and responsible for mitochondria-dependent ferroptosis under DBP exposure. Furthermore, the pivotal role of activating transcription factor 4 (ATF4) was identified in the transcriptional regulation of vdac2 by ChIP assay. And the intervention of atf4b inhibited DBP-induced VDAC2 upregulation and oligomerization. Taken together, this study reveals that ATF4-VDAC2 signaling pathway is involved in the DBP-induced ferroptosis in zebrafish ZF4 cells, contributing to the in-depth understanding of biotoxicity and the ecological risk assessment of phthalates.

Environmentally relevant levels of BPA and NOR disturb early skeletal development in zebrafish.

Bisphenol A (BPA) and fluoroquinolone antibiotics (FQs) have been detected frequently in aquatic environments. Studies have shown that high levels of BPA and FQs exposure have adverse effects on chondrogenesis in young terrestrial vertebrates. However, little is known about their combined toxicity to bone metabolism. Here, we evaluated the single and combined effects of BPA and norfloxacin (NOR, a typical species of FQs) at an environmentally relevant level (1 µg/L) on early skeletal development in zebrafish. We found that both individual and combined BPA and NOR exposure resulted in poor embryo quality and decreased calcium-phosphorus ratio. The malformation increased after exposure to BPA and NOR, and craniofacial cartilage ossification was delayed. At the molecular level, the transcriptions of genes related to ossification were down-regulated significantly, and the lysine oxidase activity decreased. Hence, we infer that an environmentally relevant concentration of BPA and NOR have adverse effects on early skeletal development in fish. In addition, combined exposure to BPA and NOR seems to have an antagonistic effect on early skeletal development.

Insight into the health risk implicated in mitochondrial toxicity of dibutyl phthalate exposure on zebrafish (Danio rerio) cells.

Dibutyl phthalate (DBP) is commonly applied plasticizer in plastic products such as face masks, easily leaches or migrates into environment and its widespread contamination posed profound health risks. Further concerns rise regarding to the toxicity of DBP at subcellular level, while little is known about the ranging effects on mitochondrial susceptibility. Present study investigated the mitochondrial impairments with implicated cell death upon DBP exposure on zebrafish cells. Elevated mitochondrial oxidative stress reduced its membrane potential and count, enhanced fragmentation, and impaired ultrastructure that showed smaller size and cristae rupture. Afterwards, the critical function of ATP synthesis was damaged and the stabilized binding capacity between DBP with mitochondrial respiratory complexes was simulated by the molecular docking. And the top pathways enrichment of mitochondrion and metabolism by transcriptome analyses verified the mitochondrial dysfunction that indicated the human diseases risks. The mitochondrial DNA (mtDNA) replication and transcription with DNA methylation modifications were also disrupted, reflecting the genotoxicity on mtDNA. Moreover, the activated autophagy and apoptosis underlying mitochondrial susceptibility integrated into cellular homeostasis changes. These findings provide the first systemic evidence broadening and illustrating the mitochondrial toxicity of DBP exposure on zebrafish model that raise concern on phthalates contamination and ecotoxicological evaluation.

Numerical Simulation on the Heat Recovery Law of Exploiting Geothermal Energy from a Closed-Loop Geothermal System Converted from an Abandoned Five-Spot Well Pattern.

Exploiting geothermal energy from abandoned wells is a research hotpot at present. However, there is still a lack of research on exploiting geothermal energy using an abandoned well pattern. Aiming at this problem, in this paper, a novel method for exploiting geothermal energy from an abandoned well pattern is proposed. An unsteady heat transfer model is proposed to study the influence of some key parameters on the production law of the novel scheme, and the proposed model is verified with field experimental data. The result indicates that there exists a critical flow rate that can change the form of the characteristic curve of the outlet temperature with production time. The change of flow rate has more influence on the outlet temperature than that of temperature. A higher geothermal gradient is conducive to production. When the total number of wells and the total flow rate of the system are fixed, fewer production wells will be conducive to production. When the number of production wells and injection wells is determined, changing the deployment of production wells and injection wells has little effect on the outlet temperature and thermal power.

[Development of Special Drive Pediatric Ventricular Assist Device].

This paper uses AVR16 SCM, programming to achieve the software of PWM (pulse width modulation) control of intelligent H bridge chip LMD18200 driver of high speed DC motor, makes special speed tablet, obtains speed signal of high speed for photocoupler PC817, through the A/D conversion and processing circuit, and realizes the LED LCD digital display speed scheme. The driver for the pediatric ventricular assist device has been used at the laboratory trial, has high performance and wide application prospect.

Rich1 negatively regulates the epithelial cell cycle, proliferation and adhesion by CDC42/RAC1-PAK1-Erk1/2 pathway.

Rich1, a previously identified Rho GTPase-activating protein (RhoGAP), was found to have close relationship with Rho GTPase family members in multiple cellular processes in nervous cells and platelets. But the exact role of Rich1 in epithelial cells remains obscure. The present investigation demonstrated that up-regulation of Rich1 could cause S-phase arrest, proliferation inhibition and adhesion decline with F-actin amount decrease in epithelial cells. Further exploration in hepatocyte HL7702 revealed that overexpression of Rich1 could greatly elevate the intrinsic GTPase activities on both of CDC42 and RAC1 by stimulating GTP hydrolysis, which consequently attenuated the activities of the Rho proteins and the phosphorylation level of those in PAK1-ERK1/2 signaling cascade. While the GAP domain deleted Rich1 variant or silence of endogenous Rich1 expression could not result in any of the biological effects. It is indicated that Rich1, completely different from in other types of cells, might act as a crucial upstream negative regulator via its GAP domain in control of epithelial cell cycle, proliferation and focal adhesion through CDC42/RAC1-PAK1-ERK1/2 signaling pathway and F-actin dynamics.

Characteristics of MnO2 catalytic ozonation of sulfosalicylic acid and propionic acid in water.

The characteristics of different types of MnO(2) catalytic ozonation of sulfosalicylic acid (SSal) and propionic acid (PPA) have been investigated in this paper. The experimental results show the dependence of catalytic activity of MnO(2) on organic compounds and the pH of solutions, but it is independent on the type of MnO(2). For example, three types of MnO(2) have not any catalytic activity when ozonation of PPA under the condition of this experiment. All MnO(2) catalytic ozonation of SSal at pH=1.0 have a greater total organic carbon removal than ozonation alone has, however, at pH=6.8 and 8.5, catalytic efficiency is not observed. Furthermore, the batch experimental results indicate that there are no direct relationship between the activity of metal oxide catalytic decomposition of ozone and that of its catalytic degradation of organic compounds.