Accurate Prediction of Rat Acute Oral Toxicity and Reference Dose for Thousands of Polycyclic Aromatic Hydrocarbon Derivatives Based on Chemometric QSAR and Machine Learning.

Acute oral toxicity is currently not available for most polycyclic aromatic hydrocarbons (PAHs), especially their derivatives, because it is cost-prohibitive to experimentally determine all of them. Here, quantitative structure-activity relationship (QSAR) models using machine learning (ML) for predicting the toxicity of PAH derivatives were developed, based on oral toxicity data points of 788 individual substances of rats. Both the individual ML algorithm gradient boosting regression trees (GBRT) and the stacking ML algorithm (extreme gradient boosting + GBRT + random forest regression) provided the best prediction results with satisfactory determination coefficients for both cross-validation and the test set.

Mining flotation reagents: Quantitative and robust analysis of metal-xanthate complexes in water.

Xanthates, common mining flotation reagents, strongly bind thiophilic metals such as copper (Cu), lead (Pb), cadmium (Cd), and zinc (Zn) and consequentially change their bioavailability and mobility upon their discharge into the environment. However, accurate quantification of the metal-xanthate complexes has remained elusive. This study develops a novel and robust method that realizes the accurate quantification of the metal-xanthate complexes resulted from single and multiple reactions of three typical xanthates (ethyl, isopropyl, and butyl xanthates) and four thiophilic metals (Cu, Pb, Cd, and Zn) in water samples.

Congener-specific fate and impact of microcystins in the soil-earthworm system.

Microcystins (MCs) have a significant influence on aquatic ecosystems, but little is known about their terrestrial fate and impact. Here, we investigated the fate of two MCs (MC-LR and MC-RR) in the soil-earthworm system, with consideration of their congener-specific impact on earthworm health, soil bacteria, and soil metabolome. Although MCs had little acute lethal effect on earthworms, they caused obvious growth inhibition and setae rupture.

Biodegradation of phthalate acid esters and whole-genome analysis of a novel Streptomyces sp. FZ201 isolated from natural habitats.

Di-n-butyl phthalate (DBP) is one of the most extensively used phthalic acid esters (PAEs) and is considered to be an emerging, globally concerning pollutant. The genus Streptomyces holds promise as a degrader of various organic pollutants, but PAE biodegradation mechanisms by Streptomyces species remain unsolved. In this study, a novel PAE-degrading Streptomyces sp.

Bioremediation of aniline aerofloat wastewater at extreme conditions using a novel isolate Burkholderia sp. WX-6 immobilized on biochar.

Aniline aerofloat (AAF) is a refractory organic pollutant in floatation wastewater. Little information is currently available on its biodegradation. In this study, a novel AAF-degrading strain named Burkholderia sp.

Development, Evaluation, and Application of Machine Learning Models for Accurate Prediction of Root Uptake of Per- and Polyfluoroalkyl Substances.

Machine learning (ML) models were developed for understanding the root uptake of per- and polyfluoroalkyl substances (PFASs) under complex PFAS-crop-soil interactions. Three hundred root concentration factor (RCF) data points and 26 features associated with PFAS structures, crop properties, soil properties, and cultivation conditions were used for the model development. The optimal ML model, obtained by stratified sampling, Bayesian optimization, and 5-fold cross-validation, was explained by permutation feature importance, individual conditional expectation plot, and 3D interaction plot.

Polyethylene and polypropylene microplastics reduce chemisorption of cadmium in paddy soil and increase its bioaccessibility and bioavailability.

Microplastics (MPs) usually coexist with heavy metals (HMs) in soil. MPs can influence HMs mobility and bioavailability, but the underlying mechanisms remain largely unexplored. Here, polyethylene and polypropylene MPs were selected to investigate their effects and mechanisms of sorption-desorption, bioaccessibility and bioavailability of cadmium (Cd) in paddy soil.

Revealing microcystin-LR ecotoxicity to earthworm (Eisenia fetida) at the intestinal cell level.

Potential adverse effects of microcystin-LR (MC-LR) on soil invertebrates have not been studied. Here we investigated the mechanism of MC-LR toxicity to earthworm (Eisenia fetida) intestine at the individual level and at the cellular level. The results showed an inverse relationship between the bodyweight and survival rate of earthworms over exposure time- and MC-LR doses in soil.

Variant-Specific Adsorption, Desorption, and Dissipation of Microcystin Toxins in Surface Soil.

Microcystins (MCs) are hepatotoxic heptapeptides identified in cyanobacterial bloom-impacted waters and soils. However, their environmental fate in soils is poorly understood, preventing reliable site assessment. This study aims to clarify the variant-specific adsorption, desorption, and dissipation of MC-LR and MC-RR in agricultural soils.

Variety-Selective Rhizospheric Activation, Uptake, and Subcellular Distribution of Perfluorooctanesulfonate (PFOS) in Lettuce ( L.).

Perfluorooctanesulfonate (PFOS) as an accumulative emerging persistent organic pollutant in crops poses severe threats to human health. Lettuce varieties that accumulate a lower amount of PFOS (low-accumulating crop variety, LACV) have been identified, but the regarding mechanisms remain unsolved. Here, rhizospheric activation, uptake, translocation, and compartmentalization of PFOS in LACV were investigated in comparison with those of high-accumulating crop variety (HACV) in terms of rhizospheric forms, transporters, and subcellular distributions of PFOS.

Mechanistic insight into esterase-catalyzed hydrolysis of phthalate esters (PAEs) based on integrated multi-spectroscopic analyses and docking simulation.

A novel PAE-hydrolyzing esterase (named Hyd) gene was screened from the genomic library of Rhodococcus sp. 2G and was successfully expressed in heterologous E. coli, which was defined as a new family of esterolytic enzymes.

Complete biodegradation of di-n-butyl phthalate (DBP) by a novel Pseudomonas sp. YJB6.

Phthalate acid esters (PAEs) are environmentally ubiquitous and have aroused a worldwide concern due to their threats to environment and human health. Di-n-butyl phthalate (DBP) is one of the most frequently observed PAEs in the environment. In this study, a novel bacterium identified as Pseudomonas sp.

Adsorption of microcystin contaminants by biochars derived from contrasting pyrolytic conditions: Characteristics, affecting factors, and mechanisms.

The growing incidence of microcystins (MCs) in the environment has become an issue of global concern for the high ecological and human health risks. Herein, a comparative adsorption of three MCs (MC-LR, MC-YR and MC-RR) by spent mushroom substrate (SMS)-derived biochars from contrasting pyrolytic conditions (temperature: 600/300 °C; and gas steam: CO2/N2) was surveyed to better understand the mechanisms and factors affecting the adsorption performance. For biochar preparation, 600 °C and CO led to greater levels of aromaticity, ash, S, and porosity, while 300 °C and N created more surface functional groups.

Bioaccumulation and Phytotoxicity and Human Health Risk from Microcystin-LR under Various Treatments: A Pot Study.

Microcystin-LR (MC-LR) is prevalent in water and can be translocated into soil-crop ecosystem via irrigation, overflow (pollution accident), and cyanobacterial manure applications, threatening agricultural production and human health. However, the effects of various input pathways on the bioaccumulation and toxicity of MCs in terrestrial plants have been hardly reported so far. In the present study, pot experiments were performed to compare the bioaccumulation, toxicity, and health risk of MC-LR as well as its degradation in soils among various treatments with the same total amount of added MC-LR (150 μg/kg).

Improved bio-electricity production in bio-electrochemical reactor for wastewater treatment using biomass carbon derived from sludge supported carbon felt anode.

Microbial fuel cell (MFC), a promising bio-electrochemical reactor could decompose organics in wastewater by redox processes of electro-active microorganism in anode and produce bio-energy, and the total MFC performance could mainly rely on electrochemical performance anode. Here, biomass carbon derived from municipal sludge was employed as low-cost and high-performance bio-anode for enhancing bioelectricity generation and wastewater treatment in MFC simultaneously. The electrochemical tests demonstrated that the large electrochemical active surface area, strong conductivity, and good biocompatibility in sludge carbon (SC) electrode resulted in higher power density (615.

High ecological and human health risks from microcystins in vegetable fields in southern China.

Frequent cyanobacterial blooms in the eutrophic waters produce a variety of toxins such as the monocyclic heptapeptide microcystins, greatly harming aquatic ecosystems and human health. However, little information of microcystins in agricultural fields is known. This field study of three common microcystin variants (MC-LR, MC-RR, and MC-YR) in vegetables (n = 161), soils (n = 161) and irrigation water samples (n = 23) collected from southern China regions affected by cyanobacteria blooms, shows their prevalence with total concentrations up to 514 μg/L water, 187 μg/kg soil (dry weight) and 382 μg/kg vegetable (fresh weight).

Stiff substrates enhance cultured neuronal network activity.

The mechanical property of extracellular matrix and cell-supporting substrates is known to modulate neuronal growth, differentiation, extension and branching. Here we show that substrate stiffness is an important microenvironmental cue, to which mouse hippocampal neurons respond and integrate into synapse formation and transmission in cultured neuronal network. Hippocampal neurons were cultured on polydimethylsiloxane substrates fabricated to have similar surface properties but a 10-fold difference in Young's modulus.

[Effect of aurora A on carcinogenesis of human prostate cancer].

Objective: To investigate whether Aurora A is involved in prostate cancer carcinogenesis.

Methods: The expressions of Aurora A mRNA and protein in prostate cancer tissue and cell line were measured using RT-PCR, immunohistochemistry and Western blot analyses. Meanwhile, A DNAzyme targeting at Aurora A mRNA was performed to detect the inhibition effect of Aurora A in regulating the growth of prostate cancer cell line PC3.

[Circadian rhythms of DNA synthesis and telomerase expression in hepatic cancer transplanted in nude mice].

Objective: To study the circadian rhythms of DNA synthesis and telomerase expression in hepatic cancer transplanted in nude mice.

Method: Sixteen BALB/C mice were synchronized with an alternative lighting regimen with 12 h for light and 12 h for darkness (12:12 LD) for 4 weeks. Hepatic cancer cells (SMMC-7721) were implanted into both flanks of each mouse.

[Preliminary analysis on human telomerase reverse transcriptase gene expression in acute leukemia].

Objective: To explore the relationship between gene expression of human telomerase reverse transcriptase (hTERT) and its clinical characteristics in leukemia.

Methods: The protocol of RT-PCR was used to detect the hTERTmRNA expressing levels in peripheral blood samples from leukemic patients under primary treatment(n=42), in complete remission(n=21), with recurrent leukemia (n=4); and from normal subjects (n=5), respectively.

Results: The positive percentage of hTERTmRNA expression was 73.