A high-throughput test of cell growth inhibition was performed using mouse embryonic stem (ES) cells to assess chemical toxicities. We herein demonstrated using a 96-well culture plate approach and the MTT assay that this method was suitable for prioritization of chemicals for their cytotoxic properties. In order to categorize chemicals, we used p53 gene-modified mouse ES cells as well as wild-type ES cells. The p53 gene is a well-known tumor suppressor and controls programmed cell death (apoptosis) and cellular senescence that is triggered by DNA-damaging agents such as alkylating agents and radiation. In the present study, p53-deficient ES cells were found to be more resistant to a tumor initiator, diethylnitrosamine (DEN), than wild-type ES cells, suggesting the inhibition of apoptosis or senescence by a dysfunction in p53. Chromosome aberrations were more frequently detected in p53-deficient ES cells than in wild-type cells, indicating genomic instability due to the deletion of p53. Other tumor initiators, methyl methanesulfonate (MMS) and N-methyl-N-nitrosourea (NMU), did not reveal apparent differences in cytotoxicity between wild-type and p53-deficient ES cells. Thus, ES test system using gene-modified ES cells may be used to categorize chemicals by detecting their characteristic effects on apoptosis, genotoxic potentials as well as general cytotoxicity.

In the present study, ameliorating role of hydrogen sulfide (H₂S) in oilseed rape (Brassica napus L.) was studied with or without application of H₂S donor sodium hydrosulfide (NaHS) (0.3 mM) in hydroponic conditions under three levels (0, 0.1 and 0.3 mM) of aluminum (Al). Results showed that addition of H₂S significantly improved the plant growth, photosynthetic gas exchange, and nutrients concentration in the leaves and roots of B. napus plants under Al stress. Exogenously applied H₂S significantly lowered the Al concentration in different plant parts, and reduced the production of malondialdehyde and reactive oxygen species by improving antioxidant enzyme activities in the leaves and roots under Al stress. Moreover, the present study indicated that exogenously applied H₂S improved the cell structure and displayed clean mesophyll and root tip cells. The chloroplast with well-developed thylakoid membranes could be observed in the micrographs. Under the combined application of H₂S and Al, a number of modifications could be observed in root tip cell, such as mitochondria, endoplasmic reticulum, and golgi bodies. Thus, it can be concluded that exogenous application of H₂S under Al stress improved the plant growth, photosynthetic parameters, elements concentration, and biochemical and ultrastructural changes in leaves and roots of B. napus.

Environmental pollution from livestock production, particularly swine production, is often managed by the use of constructed wetlands, which incorporate plants such as Myriophyllum elatinoides as a means of treating wastewater. The M. elatinoides purification system has been shown to effectively remove, via nitrification and denitrification, more than 90 % of the total nitrogen (TN) and 84 % of the NH₄ ⁺-N produced in swine wastewater. However, the mechanisms of variation in aquatic environmental factors and how the interaction of these factors affects denitrification by microorganisms in sediments remain poorly understood. In this study, the impacts of dissolved oxygen (DO), TN, NH₄ ⁺-N, and NO₃ ⁻-N on the abundance, diversity, and community distribution of denitrifiers in the sediments from different concentrations and types of wastewater including tap water (CK), two strengths of synthetic wastewater: 200 mg NH₄ ⁺-N L⁻¹ (T1) and 400 mg NH₄ ⁺-N L⁻¹ (T2), swine wastewater diluted 50 % (T3), and swine wastewater (T4) were investigated in a microcosm experiment. A significant improvement was observed in the abundance of denitrification genes (nirK and nirS) in response to increased NO₃ ⁻-N and DO in the swine wastewater sediments. The abundance of these denitrification genes was highest in the T4 sediments compared with other treatments. Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the DO, TN, and NH₄ ⁺-N positively impacted the richness index (S) of the nirK denitrifiers in T1, whereas the NO₃ ⁻-N negatively affected the Simpson diversity index (D) of nirK and nirS denitrifiers in T3 and T4. However, the NO₃ ⁻-N positively affected the nirK and nirS denitrifier community distribution, whereas the DO negatively affected the nirK and nirS denitrifier distribution in T3 and T4. These findings will be helpful in that they allow us to recognize the effects of environmental factors on the formation of the denitrifiers in the sediments in a M. elatinoides purification system.

Brominated flame retardants (BFRs) are a group of widely used compounds that, due to their limited biodegradability, exhibit excessive persistence in the environment. The persistence and high toxicity of these compounds to the natural biota causes great environmental concern. We investigated the biodegradation of the BFR dibromoneopentyl glycol (DBNPG) under continuous culture conditions using a miniature membrane bioreactor (mMBR) to assess its feasibility as a bioremediation approach. This system demonstrated long-term, stable biodegradation of DBNPG (>90 days), with an average removal rate of about 50 %. Pyrosequencing of the 16S rRNA gene of the microorganisms involved in this process revealed the dominance of reads affiliated with the genus Brevundimonas of the Alphaproteobacteria class during the different mMBR operational stages. The bacterial community was also dominated by reads affiliated with the Sinorhizobium and Sphingopyxis genera within the Alphaproteobacteria class and the Sediminibacterium genus of the Sphingobacteria class. Real-time PCR used to analyze possible changes in the population dynamics of these four dominant groups revealed their consistent presence throughout the long-term mMBR biodegradation activity. Two genera, Brevundimonas and Sphingopyxis, were found to increase in abundance during the acclimation period and then remained relatively stable, forming the main parts of the consortium over the prolonged active stage.

This study was conducted to investigate the biodegradation ability of the mixed culture of Trichoderma viride and Aspergillus niger through the study of the organic matter extracted from rice straw and the lignocellulose structure by using gas chromatography–mass spectrometer (GC-MS) and Fourier transform infrared spectroscopy (FTIR). The results of the GC-MS showed that the mixed culture possessed shorter alkane (heptane) at the end of the incubation and more kinds of organic matter (except the alkanes, 29 kinds of organic matter were detected) than the pure cultures. It could be deduced that the organic matter could indicate the degradation degree of the lignocellulose to some extent. Moreover, pinene was detected in the mixed culture on days 5 and 10, which might represent the antagonistic relationship between T. viride and A. niger. The analysis of FTIR spectrums which indirectly verified the GC-MS results showed that the mixed culture possessed a better degradation of rice straw compared with the pure culture. Therefore, the methods used in this research could be considered as effective ones to investigate the lignocellulose degradation mechanism in mixed culture.

Contamination of roxarsone has been recognized as a potential environmental hazard. In this study, Eisenia fetida samples were collected after roxarsone exposures to analyze their intestinal epithelium ultrastructure, expression levels of stress-related genes, and proteomics. Our results showed that mitochondria and endoplasmic reticulum in roxarsone-treated earthworms demonstrated variety of damages. Furthermore, 149 proteins were displayed in 2-DE, and 36 of them were identified by MALDI-TOF/TOF-MS. Those identified proteins are involved in several important processes including cell immunity, cell stress responses, and cell genetic behaviors. Our study demonstrates the toxicity responses of earthworms toward arsenic-based animal drug roxarsone with practical usefulness and demonstrates a proteomic profile change that may be critical for the roxarsone stress survival mechanisms of E. fetida. Graphical Abstract Inspiration of this referred to the form of Fig. 4 in the article “Proteomic analysis of a high aluminum tolerant yeast Rhodotorula taiwanensis RS1 in response to aluminum stress” of Chao, W et al.

This papers deals with direct measurements of dry deposition flux of total acidifying N species (gaseous HNO₃ and particulate NO₃ ⁻) and theoretically by parameterization method to vegetation (leaf surfaces) over a semiarid region in India. Annual average experimental dry deposition of NO₃ ⁻ to leaf of Cassia is 0.65 ± 0.61 mg m⁻² day⁻¹. Ambient concentrations of HNO₃ vapor and particulate NO₃ ⁻ are 1.53 and 1.24 μg m⁻³, respectively. Theoretically obtained dry deposition velocity of HNO₃ and NO₃ ⁻ are 0.74 cm s⁻¹ for both while calculated dry deposition flux of total NO₃ ⁻ is found to be 1.3 ± 0.33 mg m⁻² day⁻¹. The measured dry deposition flux of NO₃ ⁻ to Cassia leaf is in the range of theoretically obtained flux. The annual input of N as nitrate is 3.8 mmol m⁻² year⁻¹ which is lower than the other forest site in China which is probably because of low pollution than China.

The linking of various environmental chemicals exposure to neurodegenerative disorders is current. This study was undertaken to elucidate the toxic effects and the underlying biochemical mechanism of leachate obtained from Elewi Odo municipal battery recycling site (EOMABRL) using key markers of neuronal damage in rat via an oral route. Analysis of the concentrations of heavy metals showed that lead, cadmium, nickel, chromium, manganese, and iron were higher than the acceptable limits set by the regulatory authority—the World Health Organization. Whereas, copper, zinc, and cobalt were lower than permissible limits. EOMABRL was administered at 0, 20, 40, 60, 80, and 100 % concentrations to adult male rats for 60 days. An in vitro study was also carried out in the cerebellum to assess cholinesterase biochemistry assays. Following exposure, brain was collected to determine the antioxidant status. EOMABRL administration significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, and a sequential decrease in reduced glutathione (GSH) level with a concomitant increase in the accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) level was observed, when compared with the control. The treated rat had a significant (P < 0.05) increase in the activities of acetycholinesterase (AChE) and butyrylcholinesterase (BuChE). Taken together, these findings conclude that some possible mechanisms by which EOMABRL elicits neuronal disorder in male rat could be through the activation of AChE and BuChE and induction of oxidative stress with necrosis of neuronal cells.

Ammonia is a common toxicant in aquatic systems; this substance has become a critical threat to fish, especially in early life stages. This study aimed to evaluate the effects of unionized ammonia (NH₃-N: 0, 0.068, 0.138, 0.206, 0.275, 0.343, 0.412, and 0.481 mg L⁻¹) on fertilized eggs and larvae of obscure puffer Takifugu obscurus, a fish species with potential economic value. Results showed that hatch time was significantly retarded and hatch rate was significantly decreased as NH₃-N concentrations increased; newly hatched larvae exhibited high rate of abnormalities and low viability. The survival rate of larvae also decreased significantly as NH₃-N concentrations increased; larvae could tolerate NH₃-N to a less extent than embryos. NH₃-N also caused a significant decrease in superoxide dismutase (SOD) and Na⁺/K⁺ ATPase activities but not in malondialdehyde (MDA) levels of larvae. Two-way ANOVA indicated that there was a statistically significant interaction between NH₃-N concentrations and exposure times on SOD activity but not on Na⁺/K⁺ ATPase activity. Such responses indicated that an increase in ammonia concentration in surface water may negatively affect the early development of T. obscurus and thus likely impair population recruitment and persistence of this fish species.