Screening and prioritizing substances in groundwater in the Beijing-Tianjin-Hebei region of the North China Plain based on exposure and hazard assessments.

Screening and prioritizing hazardous substances in groundwater is crucial to monitor and control groundwater quality. Total of 283 substances were determined in 213 groundwater samples from the Beijing-Tianjin-Hebei region during 2019-2020. 184 substances were screened as candidates.

Spatial variation, water quality, and health risk assessment of trace elements in groundwater in Beijing and Shijiazhuang, North China Plain.

Metal(loid)s pollution of groundwater in northern China is of great concern due to the increasing shortage of fresh water resources. In the present study, total 159 of groundwater samples were collected from the Miyun-Huairou-Shunyi (MHS) districts in Beijing city and the Hutuo River Plain (HRP) in Shijiazhuang city. Nineteen trace elements dissolved in groundwater were measured.

Hormetic dose-responses for silver antibacterial compounds, quorum sensing inhibitors, and their binary mixtures on bacterial resistance of Escherichia coli.

Silver antibacterial compounds (SACs) and quorum sensing inhibitors (QSIs), as the potential antibiotic substitutes, have been recommended to prevent and treat microbial infections for the purpose of controlling the increasingly serious bacterial resistance induced by the abuse of antibiotics. However, there is little information regarding the resistance risk of these compounds, especially their mixtures. In this study, bacterial mutation and RP4 plasmid conjugative transfer among bacteria were used to characterize the bacterial endogenous and exogenous resistance, respectively.

Investigations on the influence of energy source on time-dependent hormesis: A case study of sulfadoxine to Aliivibrio fischeri in different cultivation systems.

Hormesis is a biphasic dose-response relationship featured by low-dose stimulation and high-dose inhibition. Although the hormetic phenomenon has been extensively studied over the past decades, there is little information regarding the influence of energy source on the occurrence of hormesis, especially the time-dependent one. In this study, to explore the role of cultivation system's energy source in time-dependent hormesis, the toxic dose-responses of Aliivibrio fischeri (A.

Resistance risk induced by quorum sensing inhibitors and their combined use with antibiotics: Mechanism and its relationship with toxicity.

The abuse of antibiotics has brought out serious bacterial resistance, which threatens the ecological environment and human health. Quorum sensing inhibitors (QSIs), as a new kind of potential antibiotic substitutes that are theoretically difficult to trigger bacterial resistance, are recommended to individually use or jointly use with traditional antibiotics. However, there are few studies on the resistance risk in the use of QSIs.

In-situ and ex-situ measurement of hydrophobic organic contaminants in soil air based on passive sampling: PAH exchange kinetics, non-equilibrium correction and comparison with traditional estimations.

It is a great challenge to accurately estimate chemical activity of hydrophobic organic contaminants in field soils. Ex-situ and in-situ determinations were developed for this purpose based on low-density polyethylene (LDPE) passive sampling and non-equilibrium correction by release of performance reference compounds (PRCs) previously spiked to the samplers. This work investigated kinetic processes of target contaminants' uptake into and PRCs' release from the sampler in an ex-situ soil suspension incubated for 100 days.

Hormetic dose-dependent response about typical antibiotics and their mixtures on plasmid conjugative transfer of Escherichia coli and its relationship with toxic effects on growth.

Bacterial resistance caused by the abuse of antibiotics has attracted worldwide attention. However, there are few studies exploring bacterial resistance under the environmental exposure condition of antibiotics that is featured by low-dose and mixture. In this study, sulfonamides (SAs), sulfonamide potentiators (SAPs) and tetracyclines (TCs) were used to determine the effects of antibiotics on plasmid RP4 conjugative transfer of Escherichia coli (E.

Insights into the role of energy source in hormesis through diauxic growth of bacteria in mixed cultivation systems.

Hormesis, a biphasic dose-response relationship characterized by low-dose stimulation and high-dose inhibition, has been reported to be closely related to energy sources in cultivation systems. However, few studies have clarified how the energy source influences hormesis. In this study, based on the typical diauxic patterns of Escherichia coli (E.

Similarities between the Yin/Yang Doctrine and Hormesis in Toxicology and Pharmacology.

Hormesis is a generalizable dose-response relationship characterized by low-dose stimulation and high-dose inhibition. Despite debate over this biphasic dose-response curve, hormesis is challenging central beliefs in the evaluation of chemicals or drugs and has influenced biological model selection, concentration range, study design, and hypothesis testing. We integrate the traditional Chinese philosophy - Yin/Yang doctrine - into the representation of the Western hormetic dose-response relationship and review the Yin/Yang historical philosophy contained in the hormesis concept, aiming to promote general acceptance and wider applications of hormesis.

Rhizosphere Microbiome Assembly and Its Impact on Plant Growth.

Microorganisms colonizing the plant rhizosphere provide a number of beneficial functions for their host. Although an increasing number of investigations clarified the great functional capabilities of rhizosphere microbial communities, the understanding of the precise mechanisms underlying the impact of rhizosphere microbiome assemblies is still limited. Also, not much is known about the various beneficial functions of the rhizosphere microbiome.

A trigger mechanism of herbicides to phytoplankton blooms: From the standpoint of hormesis involving cytochrome b, reactive oxygen species and nitric oxide.

The cause of phytoplankton blooms has been extensively discussed and largely attributed to favorable external conditions such as nitrogen/phosphorus resources, pH and temperature. Here from the standpoint of hormesis response, we propose that phytoplankton blooms are initiated by stimulatory effects of low concentrations of herbicides as environmental contaminants spread over estuaries and lakes. The experimental results revealed general stimulations by herbicides on Microcystis aeruginosa and Selenastrum capricornutum, with the maximum stimulation in the 30-60% range, depending on the agent and experiment.

Hormesis-induced gap between the guidelines and reality in ecological risk assessment.

Guidelines of ecological risk assessment (ERA) used worldwide, based on S-shaped threshold dose-response curve, fail to consider hormesis, a biphasic dose-response model represented as a J-shaped or an inverted U-shaped curve, that occurs in real-life environment. Now that humans are routinely exposed to chemicals below the threshold where hormetic stimulation prevails, it is noteworthy that over-strictness about chemical control also means a waste of limited resources. So hormesis leads to the gap between guidelines with S-shaped model and reality with hormesis model concerning ERA.

Regular time-dependent cross-phenomena induced by hormesis: A case study of binary antibacterial mixtures to Aliivibrio fischeri.

Time-dependent cross-phenomenon in which the cross between the actual concentration-response curve (CRC) for mixture crosses the CRCs for reference model varies with time has been frequently reported in previous studies, expressed as a heterogeneous pattern of joint toxic action. However, the variation tendency of time-dependent cross-phenomenon is rarely addressed. In this study, the joint toxic actions of binary antibacterial mixtures (i.

Correction to: Occurrence of polybrominated diphenyl ethers in floor and elevated surface house dust from Shanghai, China.

The article Occurrence of polybrominated diphenyl ethers in floor and elevated surface house dust from Shanghai, China, written by Dong Niu, Yanling Qiu, Li Li, Yihui Zhou, Xinyu Du, Zhiliang Zhu, Ling Chen and Zhifen Lin, was originally published electronically on the publisher's internet portal.

Air-soil diffusive exchange of PAHs in an urban park of Shanghai based on polyethylene passive sampling: Vertical distribution, vegetation influence and diffusive flux.

Compared with dry and wet deposition rates, air-soil exchange fluxes cannot be directly measured experimentally. Polyethylene passive sampling was applied to assess transport directions and to measure concentration gradients in order to calculate diffusive fluxes of polycyclic aromatic hydrocarbons (PAHs) across the air-soil interface in an urban park of Shanghai, China. Seven campaigns with high spatial resolution sampling at 18 heights between 0 and 200 cm above the ground were conducted in 2017-2018.

Combination of sulfonamides, silver antimicrobial agents and quorum sensing inhibitors as a preferred approach for improving antimicrobial efficacy against Bacillus subtilis.

More and more antibacterial agents are used together to treat bacterial infections in diverse fields, but the overuse of antibacterial agents may cause the environmental pollution of antibiotic resistance genes (ARGs). In order to reduce the use of antimicrobial agents, the potential joint effects of quorum-sensing inhibitors (QSIs) and traditional antimicrobial agents have been proposed to be effective. In this study, the joint effects of traditional antimicrobial agents, represented by sulfonamides (SAs) and silver antibacterial agents (silver nitrate (AgNO) and nanosilver (AgNP, 5 nm)), and five potential QSIs, were investigated using B.

A deep insight into the toxic mechanism for sulfonamides based on bacterial cell-cell communication.

Sulfonamides (SAs), a kind of commonly used antibiotics, have been frequently detected in the environment. Due to their potential threat to the ecological environment, the toxicity of SAs to bacteria have been determined in depth, and the toxic mechanism is found to target dihydropteroate synthase (DHPS). However, other toxic mechanism may also exist for SAs, which is still unclear to us.

QSAR-based investigation on antibiotics facilitating emergence and dissemination of antibiotic resistance genes: A case study of sulfonamides against mutation and conjugative transfer in Escherichia coli.

Antibiotic resistance genes (ARGs), which are emerging environmental contaminants, have posed great threats to global public health. Although extensive efforts have been undertaken to investigate ARG pollution, little attention has been paid to the structural information of antibiotics when exploring their impact on the emergence and dissemination of ARGs. In this study, setting Escherichia coli (E.

Time-Dependent Toxicities of Quorum Sensing Inhibitors to and .

Quorum sensing inhibitors (QSIs) are being used widely as a promising alternative to antibiotics and drawing attention as potential pollutants. However, the assessment methods of the toxicities of QSIs, including model organism and affecting time, have not been established. To investigate how model organism and acting time impact the toxicities of QSIs, the effect of 4 QSIs to and were determined at different exposing time in the present study.

Multiple-species hormetic phenomena induced by indole: A case study on the toxicity of indole to bacteria, algae and human cells.

Hormesis is a dose-response relationship phenomenon characterized by low-dose stimulation and high-dose inhibition. Although hormetic phenomena have been reported in broadly ranging biological areas, there is still no unified mechanism of hormesis. Investigating multiple-species hormesis of one compound and then exploring the possible mechanism may be an effective approach to clarify the reason for the occurrence of hormetic phenomena in a broad range of organisms.

Hormetic mechanism of sulfonamides on Aliivibrio fischeri luminescence based on a bacterial cell-cell communication.

Hormesis is a biphasic dose-response model with low-dose stimulation and high-dose inhibition. The mechanism for hormesis remains inconclusive, although it is becoming a central concept in toxicology. In this paper, the hormetic mechanism of sulfachloropyridazine (SCP) on Aliivibrio fischeri (A.

Occurrence of polybrominated diphenyl ethers in floor and elevated surface house dust from Shanghai, China.

House dust is the main source of human exposure to flame retardants by ingestion. This study investigated the occurrence of polybrominated diphenyl ethers (PBDEs) in indoor dust from 22 houses in Shanghai, China. House dust was separately collected from the floor and elevated furnishings surface (mostly between 0.

A swinging seesaw as a novel model mechanism for time-dependent hormesis under dose-dependent stimulatory and inhibitory effects: A case study on the toxicity of antibacterial chemicals to Aliivibrio fischeri.

Hormesis occurs frequently in broadly ranging biological areas (e.g. plant biology, microbiology, biogerontology), toxicology, pharmacology and medicine.

Mechanistic explanation of time-dependent cross-phenomenon based on quorum sensing: A case study of the mixture of sulfonamide and quorum sensing inhibitor to bioluminescence of Aliivibrio fischeri.

Cross-phenomenon in which the concentration-response curve (CRC) for a mixture crosses the CRC for the reference model has been identified in many studies, expressed as a heterogeneous pattern of joint toxic action. However, a mechanistic explanation of the cross-phenomenon has thus far been extremely insufficient. In this study, a time-dependent cross-phenomenon was observed, in which the cross-concentration range between the CRC for the mixture of sulfamethoxypyridazine (SMP) and (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone (C30) to the bioluminescence of Aliivibrio fischeri (A.

A study on the role that quorum sensing play in antibiotic-resistant plasmid conjugative transfer in Escherichia coli.

Horizontal genes transfer (HGT) plays an important role in the dissemination of antibiotic resistance genes (ARGs) in the environment. However, the mechanisms of HGT of ARGs under the influence of antibiotics in sub-MIC remain rarely explored. Moreover, given its collective nature, HGT was considered to be relative to quorum sensing (QS) system.