30 results on '"Qixing Zhou"'
Search Results
2. Triclosan Reprograms Immunometabolism and Activates the Inflammasome in Human Macrophages
- Author
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Peng Yuan, Fengge Shen, Junqiang Zhang, Shaohu Ouyang, Yuming Chen, Wei Zou, and Qixing Zhou
- Subjects
Environmental Chemistry ,General Chemistry - Abstract
To gather enough energy to respond to harmful stimuli, most immune cells quickly shift their metabolic profile. This process of immunometabolism plays a critical role in the regulation of immune cell function. Triclosan, a synthetic antibacterial component present in a wide range of consumer items, has been shown to cause immunotoxicity in a number of organisms. However, it is unclear whether and how triclosan impacts immunometabolism. Here, human macrophages were used as model cells to explore the modulatory effect of triclosan on immunometabolism. Untargeted metabolomics using integrated liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) revealed that triclosan changed the global metabolic profile of macrophages. Furthermore, Seahorse energy analysis and
- Published
- 2022
3. The Lung Microbiota Affects Pulmonary Inflammation and Oxidative Stress Induced by PM2.5 Exposure
- Author
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Simin Wang, Qixing Zhou, Yingze Tian, and Xiangang Hu
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Environmental Chemistry ,General Chemistry - Published
- 2022
4. Mitigation Effects and Associated Mechanisms of Environmentally Relevant Thiols on the Phytotoxicity of Molybdenum Disulfide Nanosheets
- Author
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Wei Zou, Chenxu Zhao, Xingli Zhang, Caixia Jin, Kai Jiang, and Qixing Zhou
- Subjects
Molybdenum ,Environmental Chemistry ,Disulfides ,Sulfhydryl Compounds ,General Chemistry ,Nanostructures - Abstract
Thorough investigations of the environmental fate and risks are necessary for the safe application of engineered nanomaterials. Nevertheless, the current understanding of potential transformations of MoS
- Published
- 2022
5. Magnetic Field-Guided MoS2/WS2 Heterolayered Nanofilm Regulates Cell Behavior and Gene Expression
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Shan Sun, Dandan Li, Shuqing Guo, Xuan Hou, Xiangang Hu, Qixing Zhou, and Jiwei Luo
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medicine.anatomical_structure ,Materials science ,Gene expression ,Cell ,medicine ,General Materials Science ,Magnetic field ,Cell biology - Published
- 2021
6. Nanocolloids, but Not Humic Acids, Augment the Phytotoxicity of Single-Layer Molybdenum Disulfide Nanosheets
- Author
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Hui Zeng, Xiangang Hu, Shaohu Ouyang, and Qixing Zhou
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Molybdenum ,chemistry.chemical_classification ,Reactive oxygen species ,media_common.quotation_subject ,Chlorella vulgaris ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Nanostructures ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,Environmental Chemistry ,Humic acid ,Phytotoxicity ,Disulfides ,Ecotoxicity ,Internalization ,Molybdenum disulfide ,Humic Substances ,Single layer ,0105 earth and related environmental sciences ,media_common - Abstract
Engineered nanomaterials (ENMs), especially transition metal dichalcogenide (TMDC), have received great attention in recent years due to their advantageous properties and applications in various fields and are inevitably released into the environment during their life cycle. However, the effect of natural nanocolloids, widely distributed in the aquatic environment, on the environmental transformation and ecotoxicity of ENMs remains largely unknown. In this study, the effects of natural nanocolloids were compared to humic acid on the environmental transformation and ecotoxicity of single-layer molybdenum disulfide (SLMoS2), a representative TMDC. SLMoS2 with nanocolloids or humic acid (HA) enhanced their dispersion and Mo ion release in deionized water. Nanocolloids induced growth inhibition, reactive oxygen species (ROS) elevation, and cell permeability. Low-toxicity SLMoS2 combined with nanocolloids will enhance the above adverse effects. SLMoS2-nanocolloids induced serious damage (cell distortion and deformation), SLMoS2 internalization, and metabolic perturbation on Chlorella vulgaris (C. vulgaris). In contrast, the addition of HA induced the growth promotion and lower ROS level, inhibited the internalization of SLMoS2, and mitigated metabolic perturbation on C. vulgaris. This work provides insights into the effect of natural nanocolloids on the behaviors and biological risks of ENMs in aquatic environments, deserving substantial future attention.
- Published
- 2021
7. Size Matters: Nano-Biochar Triggers Decomposition and Transformation Inhibition of Antibiotic Resistance Genes in Aqueous Environments
- Author
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Qixing Zhou, Baoshan Xing, Fei Lian, Shiguo Gu, Wenchao Yu, and Zhenyu Wang
- Subjects
Aqueous solution ,Chemistry ,Radical ,Drug Resistance, Microbial ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Decomposition ,Anti-Bacterial Agents ,Transformation (genetics) ,chemistry.chemical_compound ,Adsorption ,Charcoal ,Environmental chemistry ,Biochar ,Environmental Chemistry ,Fragmentation (cell biology) ,DNA ,0105 earth and related environmental sciences - Abstract
Antibiotic resistance genes (ARGs) are considered to be a type of emerging contaminant; their interaction with biochar (BC) could affect their dissemination and fate in the environment. Although adsorption of ARGs onto bulk-BC has been reported, the interaction with nanosized BC (nano-BC) is largely unknown. In this study, the interactions of a model extracellular DNA (eDNA, calf thymus DNA) and two typical ARGs (ampC and ermB) extracted from a natural river with bulk- and nano-BCs from two pyrolysis temperatures (400 and 700 °C) were investigated. Only adsorption was observed on bulk-BCs, while not only adsorption but also fragmentation of these eDNA molecules was found to occur on nano-BCs. Also, their replication was greatly inhibited by nano-BCs. The electron paramagnetic resonance results indicated that hydroxyl radicals produced from persistent free radicals (PFRs) on nano-BCs played a major role in the damage of eDNA. Moreover, the direct contact with nonradical reacting sites and PFRs on nano-BCs also contributed to the decay of eDNA. Comparatively, PFRs in bulk-BCs were difficult to be reached by eDNA because of steric hindrance and played a negligible role in destroying eDNA. These findings highlight the importance of the size effect in evaluating the reactivity and related environmental risks of PFRs on BC and improve our understanding on the interaction between ARGs and BC.
- Published
- 2020
8. Natural Nanocolloids Mediate the Phytotoxicity of Graphene Oxide
- Author
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Hui Zeng, Qixing Zhou, Xiangang Hu, Yue Wang, and Shaohu Ouyang
- Subjects
Proteomics ,chemistry.chemical_classification ,Reactive oxygen species ,DNA damage ,Fatty acid ,Oxides ,General Chemistry ,010501 environmental sciences ,Photosynthesis ,Photosystem I ,behavioral disciplines and activities ,01 natural sciences ,Nanostructures ,chemistry ,mental disorders ,Biophysics ,Environmental Chemistry ,Humic acid ,Graphite ,Phytotoxicity ,Ecotoxicity ,0105 earth and related environmental sciences - Abstract
Nanocolloids (Ncs) are ubiquitous in natural surface waters. However, the effects of Ncs on the fate and ecotoxicity of graphene oxide (GO, a popular engineered nanomaterial (ENM)) remain largely unknown. Ncs exhibit strong adsorption affinity (KL = 1.93 L/mg) and high adsorption capacity (176.2 mg/g) for GO. After Ncs hybridization, GO nanosheets became scrolls, and the aggregation rate of GO decreased. The influence of humic acid and Ncs on GO toxicity was compared. Humic acid mitigated the phytotoxicity of GO. However, GO and GO-Ncs were found to have an envelopment effect on algal cells, and both could enter algal cells. GO-Ncs induced higher reactive oxygen species (ROS) generation, stronger DNA damage and plasmolysis, and more obvious inhibition of photosynthesis compared to GO. Proteomic analysis revealed that photosystem I- and II-related proteins (e.g., E1ZQR2 and E1ZPG5) were regulated more significantly in the GO-Ncs groups than in the GO groups. A combined proteomic and metabolomic analysis showed that inhibition of carbohydrate, fatty acid, and amino acid metabolism contributed to ROS generation. Given the high concentrations and activity of Ncs, the above results highlight the need for reconsideration of the Ncs-mediated environmental behaviors and risks of ENMs and other pollutants.
- Published
- 2020
9. WS2 Nanosheets at Noncytotoxic Concentrations Enhance the Cytotoxicity of Organic Pollutants by Disturbing the Plasma Membrane and Efflux Pumps
- Author
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Qixing Zhou, Xiangang Hu, and Peng Yuan
- Subjects
Pollutant ,Membrane permeability ,Substrate (chemistry) ,General Chemistry ,010501 environmental sciences ,Phosphate ,01 natural sciences ,Triclosan ,chemistry.chemical_compound ,Membrane ,chemistry ,Environmental chemistry ,Environmental Chemistry ,Efflux ,Xenobiotic ,0105 earth and related environmental sciences - Abstract
Emerging transition-metal dichalcogenide (TMDC) nanosheets, such as WS2 nanosheets, have shown tremendous potential for use in many fields such as intelligent manufacturing and environmental protection. However, considerable knowledge gaps still exist regarding the impact of TMDCs on environmental risks, especially risks involving organic pollutants. Here, a synergistic toxicity between WS2 nanosheets and organic pollutants (triclosan or tris(1,3-dichloro-2-propyl) phosphate) was found using the median-effect and combination index equations. In particular, the effect of synergy had a higher magnitude at low cytotoxicity levels and a noncytotoxic concentration of WS2 nanosheets clearly enhanced the cytotoxicity and intracellular accumulation of organic pollutants. On the one hand, WS2 nanosheets damaged the plasma membrane and cytoskeleton, resulting in increased membrane permeability and organic pollutant uptake. On the other hand, as shown by fluorescence substrate accumulation experiments and molecular dynamics simulations, WS2 nanosheets affected the secondary structure of the efflux pumps and competitively bound with efflux pumps, blocking xenobiotic removal. This work emphasized that TMDCs, especially at the noncytotoxic level, in combination with organic pollutants caused damage that cannot be ignored, providing insight into comprehensive safety assessment and the specific toxicological mechanisms of TMDCs that accompany organic pollutant exposure.
- Published
- 2020
10. Exposure to PbSe Nanoparticles and Male Reproductive Damage in a Rat Model
- Author
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Lu Liu, Zongkai Yue, Qingzhao Li, Ruiren Zhou, and Qixing Zhou
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Male ,medicine.medical_specialty ,Apoptosis ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Downregulation and upregulation ,Internal medicine ,medicine ,Animals ,Environmental Chemistry ,Selenium Compounds ,0105 earth and related environmental sciences ,Chemistry ,Endoplasmic reticulum ,technology, industry, and agriculture ,General Chemistry ,Sperm ,Rats ,Oxidative Stress ,Endocrinology ,Lead ,Toxicity ,Nanoparticles ,Reproductive toxicity ,Oxidative stress ,Hormone - Abstract
PbSe nanoparticles (PbSe-NPs) attract ever-growing interest owing to their great promise in various fields. However, potential toxic effects of PbSe-NPs on male reproductive systems have not been reported. This study aimed to determine whether early-life exposure to PbSe-NPs could affect male reproductive systems and other related health effects in rats. The male rats were intraperitoneally injected with 10 mg/kg/week PbSe-NPs for 60 days followed by a series of reproductive-related analyses. We found that the nanoparticles could accumulate in testes in a size-dependent manner. Furthermore, accumulation of PbSe-NPs resulted in oxidative stress and disorder of normal serum sex hormones. Endoplasmic reticulum and mitochondria-mediated cell apoptosis were triggered via oxidative stress, as shown by upregulation of cytoplasmic Cyt-c, Bax, cleaved Caspase-3, GRP78, and Caspase-12. Notably, PbSe-NP administration led to reduction in the quantity and quality of sperm, which caused a great fertility decrease. In contrast, released Pb2+ from PbSe-NPs did not result in any testis toxicity and fertility declines. These results demonstrate that PbSe-NPs could cause severe reproductive toxicity in a size-dependent manner and these toxic effects should be responsible for PbSe-NPs themselves rather than released Pb2+. The application of PbSe-NPs might be a double-edged sword, and corresponding measures should be taken before use.
- Published
- 2019
11. Dissolved Oxygen and Visible Light Irradiation Drive the Structural Alterations and Phytotoxicity Mitigation of Single-Layer Molybdenum Disulfide
- Author
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Xiangang Hu, Qixing Zhou, Xingli Zhang, and Wei Zou
- Subjects
Molybdenum ,Light ,Chemistry ,chemistry.chemical_element ,General Chemistry ,010501 environmental sciences ,Photochemistry ,01 natural sciences ,Oxygen ,Plasmolysis ,chemistry.chemical_compound ,Environmental Chemistry ,Phytotoxicity ,Disulfides ,Surface charge ,Dissolution ,Molybdenum disulfide ,0105 earth and related environmental sciences ,Nanosheet - Abstract
Understanding environmental fate is a prerequisite for the safe application of nanoparticles. However, the fundamental persistence and environmental transformation of single-layer molybdenum disulfide (SLMoS2, a 2D nanosheet attracting substantial attention in various fields) remain largely unknown. The present work found that the dissolution of SLMoS2 was pH and dissolved oxygen dependent and that alterations in phase composition significantly occur under visible light irradiation. The 1T phase was preferentially oxidized to yield soluble species (MoO42- and SO42-), and the 2H phase remained as a residual. The transformed SLMoS2 exhibited a ribbon-like and multilayered structure and low colloidal stability due to the loss of surface charge. Dissolved oxygen competitively captured the electrons of SLMoS2 to generate superoxide radicals and accelerated the dissolution of nanosheets. Compared to pristine 1T-phase SLMoS2, the transformed 2H-phase SLMoS2 could not easily enter algal cells and induced a low developmental inhibition, oxidative stress, plasmolysis, photosynthetic toxicity and metabolic perturbation. The downregulation of amino acids and upregulation of unsaturated fatty acids contributed to the higher toxicity of 1T-phase SLMoS2. The dissolved ions did not induce apparent phytotoxicity. The connections between environmental transformation (phase change and ion release) and phytotoxicity provide insights into the safe design and evaluation of 2D nanomaterials.
- Published
- 2019
12. The Phases of WS2 Nanosheets Influence Uptake, Oxidative Stress, Lipid Peroxidation, Membrane Damage, and Metabolism in Algae
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Peng Yuan, Qixing Zhou, and Xiangang Hu
- Subjects
chemistry.chemical_classification ,Reactive oxygen species ,02 engineering and technology ,General Chemistry ,Metabolism ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,Photosynthesis ,medicine.disease_cause ,01 natural sciences ,Nanomaterials ,Lipid peroxidation ,chemistry.chemical_compound ,Membrane ,chemistry ,Phase (matter) ,Biophysics ,medicine ,Environmental Chemistry ,0210 nano-technology ,Oxidative stress ,0105 earth and related environmental sciences - Abstract
Application of transition metal dichalcogenide (TMDC) nanosheets with different phases have attracted much attention in various fields. However, the effects of TMDC phases on environmental biology remain largely unknown. In this study, chemically exfoliated WS2 nanosheets (Ce-WS2, mainly the 1T phase) and annealed exfoliated WS2 nanosheets (Ae-WS2, 2H phase) were fabricated to serve as representative TMDC nanomaterials. Ce-WS2 showed higher levels of cellular uptake, oxidative stress, lipid peroxidation, membrane damage, and inhibition of photosynthesis than Ae-WS2 in Chlorella vulgaris. These differences were attributed to the higher electron conductivity and higher separation efficiency of electrons and holes in the 1T phase, a typical feature of Ce-WS2. Correspondingly, 2H-phase Ae-WS2 exhibited lower photooxidation/reduction activity and a lower ability to generate reactive oxygen species (mainly •OH) under visible-light irradiation. 1T-phase Ce-WS2 dissolved more readily than Ae-WS2 and released more...
- Published
- 2018
13. Screening Priority Factors Determining and Predicting the Reproductive Toxicity of Various Nanoparticles
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Li Mu, Qixing Zhou, Xiangang Hu, Zhan Ban, and Anqi Sun
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Chemistry ,Reproduction ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Computational biology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Rats ,Nanotoxicology ,Toxicity ,Animals ,Nanoparticles ,Environmental Chemistry ,0210 nano-technology ,Reproductive toxicity ,0105 earth and related environmental sciences - Abstract
Due to the numerous factors (e.g., nanoparticle [NP] properties and experimental conditions) influencing nanotoxicity, it is difficult to identify the priority factors dominating nanotoxicity. Herein, by integrating data from the literature and a random forest model, the priority factors determining reproductive toxicity were successfully screened from highly heterogeneous data. Among 10 factors from more than 18 different NPs, the NP type and the exposure pathway were found to dominantly determine NP accumulation. The reproductive toxicity of various NPs primarily depended on the NP type and the toxicity indicators. Nanoparticles containing major elements (e.g., Zn and Fe) tended to accumulate in rats but induced lower toxicity than NPs containing noble elements. Compared with other exposure pathways, i.p. injection posed significantly higher risks for NP accumulation. By combining similarity network analysis and hierarchical clustering, the sources of highly heterogeneous data were identified, the factor-toxicity dependencies were extracted and visualized, and the prediction of nanotoxicity was then achieved based on the screened priority factors. The present work provides insights for the design of animal experiments and the illustration and prediction of nanotoxicity.
- Published
- 2018
14. Swift Acid Rain Sensing by Synergistic Rhizospheric Bioelectrochemical Responses
- Author
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Qing Du, Tian Li, Jingkun An, Lili Wan, Nan Li, Qixing Zhou, Chengmei Liao, Lean Zhou, Xin Wang, and Zhiyong Jason Ren
- Subjects
Glutamic Acid ,Bioengineering ,Acid Rain ,02 engineering and technology ,010501 environmental sciences ,Photosynthetic efficiency ,Plant Roots ,01 natural sciences ,Photosynthesis ,Instrumentation ,Rice plant ,0105 earth and related environmental sciences ,Fluid Flow and Transfer Processes ,Aspartic Acid ,Rhizosphere ,Alanine ,Chemistry ,Process Chemistry and Technology ,fungi ,Galactose ,food and beverages ,Oryza ,Electrochemical Techniques ,021001 nanoscience & nanotechnology ,Plant Leaves ,Glucose ,Environmental chemistry ,Acid rain ,0210 nano-technology ,Environmental Monitoring - Abstract
Acid rain poses significant threats to crops and causes a decline in food production, but current monitoring and response to acid rain damage is either slow or expensive. The direct damage observation on plants can take several hours to days when the damage is irreversible. This study presents a real time bioelectrochemical monitoring approach that can detect acid rain damage within minutes. The rhizospheric bioelectrochemical sensor (RBS) takes advantage of the fast chain responses from leaves to roots, and then to the microbial electrochemical reactions in the rhizosphere. Immediate and repeatable current fluctuations were observed within 2 min after acid rain, and such changes were found to correspond well to the changes in rhizospheric organic concentration and electrochemical responses. Such correlation not only can be observed during acid rain events that can be remedied via rinsing, but it was also validated when such damage is irreversible, resulted in zero current, photosynthetic efficiency, and electrochemical signals. The alanine, aspartate, and glutamate metabolism and galactose metabolism in leaves and roots were inhibited by the acid rain, which resulted in the decrease of rhizodeposits such as fumaric acid, d-galactose, and d-glucose. These changes resulted in reduced electroactivity of anodic microorganisms, which was confirmed by a reduced redox current, a narrower spectrum in differential pulse voltammetry, and the loss of peak in the Bode plot. These findings indicate that the RBS process can be a simple, swift, and low-cost monitoring tool for acid rain that allows swift remediation measures, and its potential may be broadened to other environmental monitoring applications.
- Published
- 2018
15. Nanocolloids in Natural Water: Isolation, Characterization, and Toxicity
- Author
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Shaohu Ouyang, Xiangang Hu, Ruiren Zhou, Xiaokang Li, Qixing Zhou, and Xinyu Miao
- Subjects
China ,Chlorophyll a ,Silver ,Starch ,Metal Nanoparticles ,02 engineering and technology ,010501 environmental sciences ,medicine.disease_cause ,01 natural sciences ,Plasmolysis ,chemistry.chemical_compound ,medicine ,Environmental Chemistry ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Reactive oxygen species ,Chlorophyll A ,General Chemistry ,021001 nanoscience & nanotechnology ,Fluorescence ,Chloroplast ,Ultrafiltration (renal) ,chemistry ,Environmental chemistry ,Chlorella vulgaris ,0210 nano-technology ,Water Pollutants, Chemical ,Genotoxicity - Abstract
Nanocolloids are widespread in natural water systems, but their characterization and ecological risks are largely unknown. Herein, tangential flow ultrafiltration (TFU) was used to separate and concentrate nanocolloids from surface waters. Unexpectedly, nanocolloids were present in high concentrations ranging from 3.7 to 7.2 mg/L in the surface waters of the Harihe River in Tianjin City, China. Most of the nanocolloids were 10-40 nm in size, contained various trace metals and polycyclic aromatic hydrocarbons, and exhibited fluorescence properties. Envelopment effects and aggregation of Chlorella vulgaris in the presence of nanocolloids were observed. Nanocolloids entered cells and nanocolloid-exposed cells exhibited stronger plasmolysis, chloroplast damage and more starch grains than the control cells. Moreover, nanocolloids inhibited the cell growth, promoted reactive oxygen species (ROS), reduce the chlorophyll a content and increased the cell permeability. The genotoxicity of nanocolloids was also observed. The metabolomics analysis revealed a significant ( p0.05) downregulation of amino acids and upregulation of fatty acids contributing to ROS increase, chlorophyll a decrease and plasmolysis. The present work reveals that nanocolloids, which are different from specific, engineered nanoparticles (e.g., Ag nanoparticles), are present at high concentrations, exhibit an obvious toxicity in environments, and deserve more attention in the future.
- Published
- 2018
16. Adsorption of Low-Molecular-Weight Amines in Aqueous Solutions to Zeolites: An Approach to Impeding Low-Molecular-Weight Amines from Regenerating N-Nitrosamines
- Author
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Xiaoyan Guo, Qilin Li, Qixing Zhou, Wanli Hu, Man Zhang, Huaiqi Shao, Chunyu Li, Shougang Fan, and Hailan Yun
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chemistry.chemical_classification ,Diethylamine ,Aqueous solution ,General Chemical Engineering ,Inorganic chemistry ,Aromatic amine ,General Chemistry ,010501 environmental sciences ,010402 general chemistry ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,Aniline ,chemistry ,Organic chemistry ,Ethylamine ,Zeolite ,Dimethylamine ,0105 earth and related environmental sciences - Abstract
The combined effects of the porous structure, acidity, and ion-exchange properties of zeolites and the structures of the degradation products of nitrosamines in aqueous solution on adsorption were evaluated. The degradation products of nitrosamines including the aliphatic low-molecular-weight amines methylamine, dimethylamine, ethylamine, and diethylamine and the aromatic amine aniline all exhibited significant adsorption affinities to HZSM-5 zeolites, and aliphatic low-molecular-weight amines exhibited much greater adsorption affinities to HY zeolite than to NaY and HZSM-5 zeolites, but aromatic amines exhibited little adsorption affinity to HY and NaY zeolites. The results of the pH-dependency experiments further indicated that the acidity and polarity of the adsorbates and the acidity of the adsorbents play a combinational role in determining the significance of the adsorption interactions between low-molecular-weight amines in aqueous solution and zeolites. We propose that the acid–base and electrosta...
- Published
- 2017
17. Bioelectrochemical Sensor Using Living Biofilm To in Situ Evaluate Flocculant Toxicity
- Author
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Qixing Zhou, Lean Zhou, Nan Li, Xin Wang, Hongwen Sun, Tian Li, Junhui Li, and Jingkun An
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In situ ,Flocculation ,Inorganic chemistry ,chemical and pharmacologic phenomena ,Bioengineering ,02 engineering and technology ,010501 environmental sciences ,Electrochemistry ,complex mixtures ,01 natural sciences ,chemistry.chemical_compound ,Instrumentation ,0105 earth and related environmental sciences ,Fluid Flow and Transfer Processes ,biology ,Chemistry ,Alum ,Process Chemistry and Technology ,Biofilm ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Toxicity ,Cyclic voltammetry ,0210 nano-technology ,Bacteria ,Nuclear chemistry - Abstract
Flocculants have been used to clarify water for thousands of years. However, the in situ evaluation of flocculant toxicity is difficult because flocculants usually exist as growing complex flocs which is hard to monitor. With alum (KAl(SO4)2·12H2O) as the typical flocculant, a bioelectrochemical sensor is designed to in situ detect its bacterial toxicity. The attenuation ratio of current densities linearly increased with alum concentration (R2 > 0.98) with a slope of 0.0054 A m–2 drop per mg L–1 of alum, indicating a typical toxic response of alum. Turnover and nonturnover cyclic voltammetries (CVs) revealed that the alum inhibited the electrochemical activity of bacteria rather than changing the electron transfer pathways. Alum also hindered the diffusion by flocculation at a concentration larger than 100 mg L–1, which was further confirmed by the linear decrease in viability when biofilm thickness increased. It was revealed that both inactivation of biofilm and influences on diffusion by alum can be det...
- Published
- 2016
18. Nationwide Distribution of Per- and Polyfluoroalkyl Substances in Outdoor Dust in Mainland China From Eastern to Western Areas
- Author
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Shuai Chang, Hongwei Hu, Hongwen Sun, Zhiwei Gan, Yiming Yao, Qixing Zhou, and Yangyang Zhao
- Subjects
China ,Fluorocarbons ,010504 meteorology & atmospheric sciences ,Chemistry ,Dust ,General Chemistry ,Specific adsorption ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Perfluorooctane ,Altitude ,Environmental chemistry ,Environmental Chemistry ,Organic chemistry ,Perfluorooctanoic acid ,Environmental Pollutants ,Mineral particles ,Caprylates ,Sulfonic Acids ,Fluorotelomer ,Phosphoric acid ,Environmental Monitoring ,0105 earth and related environmental sciences - Abstract
From eastern to western areas, per- and polyfluoroalkyl substances (PFASs) were detected at substantial levels in the outdoor dust across mainland China. Urban samples generally showed higher levels compared with those of rural samples. Compared with neutral PFASs, ionizable PFASs (C4-C12 perfluoroalkyl carboxylic acids and C4/C8 perfluoroalkyl sulfonic acids) were more abundant, with the highest total concentration up to 1.6 × 10(2) ng/g and perfluorooctanoic acid (PFOA) being a predominant analogue. Fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphoric acid diesters (DiPAPs) were both detected in most samples with total concentrations of 0.12-32 and 0.030-20 ng/g, respectively. Perfluorooctane sulfonamidoethanols/sulfonamides (FOSE/As) were detected at low frequencies (
- Published
- 2016
19. Widespread Occurrence of Benzotriazoles and Benzothiazoles in Tap Water: Influencing Factors and Contribution to Human Exposure
- Author
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Junjie Zhang, Qixing Zhou, Lei Wang, and Hongwen Sun
- Subjects
China ,Wastewater ,010501 environmental sciences ,01 natural sciences ,Tap water ,Humans ,Environmental Chemistry ,Benzothiazoles ,Cities ,Groundwater ,Effluent ,0105 earth and related environmental sciences ,Drinking Water ,010401 analytical chemistry ,Environmental engineering ,Environmental Exposure ,General Chemistry ,Environmental exposure ,Contamination ,0104 chemical sciences ,Human exposure ,Environmental chemistry ,Environmental science ,Sewage treatment ,Surface water ,Water Pollutants, Chemical - Abstract
Despite the frequent detection of benzotriazoles (BTRs) and benzothiazoles (BTHs) in groundwater and surface-water environments, knowledge on their occurrence and profile in tap water is still scarce. This study demonstrates widespread occurrence of these compounds in tap water from 51 major cities in China, which have ranges of
- Published
- 2016
20. Uptake Pathway, Translocation, and Isomerization of Hexabromocyclododecane Diastereoisomers by Wheat in Closed Chambers
- Author
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Bing Li, Qixing Zhou, Hongwen Sun, Jiayao Xu, Yanwei Zhang, and Hongkai Zhu
- Subjects
0211 other engineering and technologies ,Stereoisomerism ,Chromosomal translocation ,02 engineering and technology ,010501 environmental sciences ,Plant Roots ,01 natural sciences ,Soil ,chemistry.chemical_compound ,Isomerism ,Soil Pollutants ,Environmental Chemistry ,Triticum ,0105 earth and related environmental sciences ,Hexabromocyclododecane ,021110 strategic, defence & security studies ,Chromatography ,Plant roots ,Chemistry ,Diastereomer ,Biological Transport ,General Chemistry ,Hydrocarbons, Brominated ,Plant Leaves ,Linear relationship ,Enantiomer ,Isomerization ,Environmental Monitoring - Abstract
To study the uptake pathways of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDs) in wheat, four closed chambers were designed to expose wheat to HBCDs via air and/or soil for 4 weeks. The results showed that HBCDs could be absorbed by wheat both via root from soil and via leaf from air. The Rt values (ratio of HBCDs from root-to-leaf translocation to the total accumulation in leaves) ranging from 14.4 to 29.8% suggested that acropetal translocation within wheat was limited. A negative linear relationship was found between log Rt and log Kow of the HBCD diastereoisomers (p0.05). The bioconcentration factors (BCFs, (μg/g wheat tissues)/(μg/g soil)) were in the order α-β-γ-HBCD in wheat roots and stems, being negatively related to their Kow values. No such correlation was found in leaves, where the HBCDs came mainly from air distribution. The results of enantiomeric fractions indicated that the (-)-enantiomer of α- and γ-HBCDs and the (+)-β-enantiomer were selectively accumulated. Furthermore, β- and γ-HBCDs were transformed to α-HBCD in the wheat, with 0.309-4.80% and 0.920-8.40% bioisomerization efficiencies at the end of the experiment, respectively, being the highest in leaves. Additionally, no isomerization product from α-HBCD was found.
- Published
- 2016
21. Effects of Graphene Oxide and Oxidized Carbon Nanotubes on the Cellular Division, Microstructure, Uptake, Oxidative Stress, and Metabolic Profiles
- Author
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Li Mu, Shaohu Ouyang, Xiangang Hu, Jing An, and Qixing Zhou
- Subjects
Cell division ,Cell Survival ,medicine.disease_cause ,Plasmolysis ,Valine ,medicine ,Environmental Chemistry ,Membrane Potential, Mitochondrial ,chemistry.chemical_classification ,Reactive oxygen species ,Nanotubes, Carbon ,Lysine ,Fatty acid ,General Chemistry ,Nanostructures ,Amino acid ,Oxidative Stress ,chemistry ,Biochemistry ,Nanotoxicology ,Fatty Acids, Unsaturated ,Graphite ,Chlorella vulgaris ,Reactive Oxygen Species ,Oxidation-Reduction ,Biomarkers ,Cell Division ,Oxidative stress - Abstract
Nanomaterial oxides are common formations of nanomaterials in the natural environment. Herein, the nanotoxicology of typical graphene oxide (GO) and carboxyl single-walled carbon nanotubes (C-SWCNT) was compared. The results showed that cell division of Chlorella vulgaris was promoted at 24 h and then inhibited at 96 h after nanomaterial exposure. At 96 h, GO and C-SWCNT inhibited the rates of cell division by 0.08-15% and 0.8-28.3%, respectively. Both GO and C-SWCNT covered the cell surface, but the uptake percentage of C-SWCNT was 2-fold higher than that of GO. C-SWCNT induced stronger plasmolysis and mitochondrial membrane potential loss and decreased the cell viability to a greater extent than GO. Moreover, C-SWCNT-exposed cells exhibited more starch grains and lysosome formation and higher reactive oxygen species (ROS) levels than GO-exposed cells. Metabolomics analysis revealed significant differences in the metabolic profiles among the control, C-SWCNT and GO groups. The metabolisms of alkanes, lysine, octadecadienoic acid and valine was associated with ROS and could be considered as new biomarkers of ROS. The nanotoxicological mechanisms involved the inhibition of fatty acid, amino acid and small molecule acid metabolisms. These findings provide new insights into the effects of GO and C-SWCNT on cellular responses.
- Published
- 2015
22. Envelopment–Internalization Synergistic Effects and Metabolic Mechanisms of Graphene Oxide on Single-Cell Chlorella vulgaris Are Dependent on the Nanomaterial Particle Size
- Author
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Shaohu Ouyang, Xiangang Hu, and Qixing Zhou
- Subjects
Chlorophyll ,Materials science ,Cell division ,media_common.quotation_subject ,Cell ,Gas Chromatography-Mass Spectrometry ,Permeability ,Plasmolysis ,law.invention ,Nanomaterials ,law ,Quantum Dots ,Spectroscopy, Fourier Transform Infrared ,medicine ,General Materials Science ,Amino Acids ,Particle Size ,Internalization ,media_common ,Membrane Potential, Mitochondrial ,Graphene ,Chlorophyll A ,Cell Membrane ,Oxides ,Nanostructures ,Oxidative Stress ,Membrane ,medicine.anatomical_structure ,Biochemistry ,Nanotoxicology ,Biophysics ,Graphite ,Chlorella vulgaris ,Cell Division - Abstract
The interactions between nanomaterials and cells are fundamental in biological responses to nanomaterials. However, the size-dependent synergistic effects of envelopment and internalization as well as the metabolic mechanisms of nanomaterials have remained unknown. The nanomaterials tested here were larger graphene oxide nanosheets (GONS) and small graphene oxide quantum dots (GOQD). GONS intensively entrapped single-celled Chlorella vulgaris, and envelopment by GONS reduced the cell permeability. In contrast, GOQD-induced remarkable shrinkage of the plasma membrane and then enhanced cell permeability through strong internalization effects such as plasmolysis, uptake of nanomaterials, an oxidative stress increase, and inhibition of cell division and chlorophyll biosynthesis. Metabolomics analysis showed that amino acid metabolism was sensitive to nanomaterial exposure. Shrinkage of the plasma membrane is proposed to be linked to increases in the isoleucine levels. The inhibition of cell division and chlorophyll a biosynthesis was associated with decreases in aspartic acid and serine, the precursors of chlorophyll a. The increases in mitochondrial membrane potential loss and oxidative stress were correlated with an increase in linolenic acid. The above metabolites can be used as indicators of the corresponding biological responses. These results enhance our systemic understanding of the size-dependent biological effects of nanomaterials.
- Published
- 2015
23. Highly Efficient Antibacterial and Pb(II) Removal Effects of Ag-CoFe2O4-GO Nanocomposite
- Author
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Shuanglong Ma, Yanan Jia, Sihui Zhan, and Qixing Zhou
- Subjects
Silver ,Materials science ,Cell Survival ,Analytical chemistry ,Metal Nanoparticles ,Nanoparticle ,Bacterial Physiological Phenomena ,Ferric Compounds ,Nanocomposites ,Water Purification ,Nanomaterials ,symbols.namesake ,X-ray photoelectron spectroscopy ,Water Pollutants ,General Materials Science ,Fourier transform infrared spectroscopy ,Nanocomposite ,Oxides ,Cobalt ,Anti-Bacterial Agents ,Disinfection ,Lead ,symbols ,Graphite ,Cyclic voltammetry ,Raman spectroscopy ,Antibacterial activity ,Nuclear chemistry - Abstract
Ag-CoFe2O4-graphene oxide (Ag-CoFe2O4-GO) nanocomposite was synthesized by doping silver and CoFe2O4 nanoparticles on the surface of GO, which was used to purify both bacteria and Pb(II) contaminated water. The Ag-CoFe2O4-GO nanomaterial was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), cyclic voltammetry (CV), and magnetic property tests. It can be found that Ag-CoFe2O4-GO nanocomposite exhibited excellent antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus compared with CoFe2O4, Ag-CoFe2O4, and CoFe2O4-GO composite. This superior disinfecting effect was possibly attributed to the combination of GO nanosheets and Ag nanoparticles. Several antibacterial factors including temperature, time, and pH were also investigated. It was obvious that E. coli was more susceptible than S. aureus toward all the four types of nanomaterials. The structural difference of bacterial membranes should be responsible for the resistant discrepancy. We also found that Ag-CoFe2O4-GO inactivated both bacteria in an irreversibly stronger manner than Ag-CoFe2O4 and CoFe2O4-GO. The Pb(II) removal efficiency with all the nanomaterials showed significant dependence on the surface area and zeta potential of the materials. In this work, not only did we demonstrate the simultaneous superior removal efficiency of bacteria and Pb(II) by Ag-CoFe2O4-GO but also the antibacterial mechanism was discussed to have a better understanding of the interaction between Ag-CoFe2O4-GO and bacteria. In a word, taking into consideration the easy magnetic separation, bulk availability, and irreversibly high antibacterial activity of Ag-CoFe2O4-GO, it is the very promising candidate material for advanced antimicrobial or Pb(II) contaminated water treatment.
- Published
- 2015
24. Ambient Water and Visible-Light Irradiation Drive Changes in Graphene Morphology, Structure, Surface Chemistry, Aggregation, and Toxicity
- Author
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Xiangang Hu, Qixing Zhou, and Ming Zhou
- Subjects
Light ,Surface Properties ,Protein Carbonylation ,Kinetics ,Oxide ,Nanotechnology ,law.invention ,chemistry.chemical_compound ,law ,Toxicity Tests ,Environmental Chemistry ,Irradiation ,Surface charge ,Singlet Oxygen ,Graphene ,Singlet oxygen ,Water ,Oxides ,General Chemistry ,chemistry ,Chemical engineering ,Nanotoxicology ,Graphite ,Chlorella vulgaris ,Reactive Oxygen Species ,Oxidation-Reduction - Abstract
The environmental behaviors and risks associated with graphene have attracted considerable attention. However, the fundamental effects of ambient water and visible-light irradiation on the properties and toxicity of graphene remain unknown. This work revealed that hydration and irradiation result in the transformation of large-sheet graphene to long-ribbon graphene. The thickness of the treated graphene decreased, and oxides were formed through the generation of singlet oxygen. In addition, hydration and irradiation resulted in greater disorder in the graphene structure and in the expansion of the d-spacing of the structure due to the introduction of water molecules and modifications of the functional groups. Oxidative modifications with two-stage (fast and low) kinetics enhanced the number of negative surface charges on the graphene and enhanced graphene aggregation. The above property alterations reduced the nanotoxicity of graphene to algal cells by reducing the generation of reactive oxygen species, diminishing protein carbonylation and decreasing tail DNA. A comparative study using graphene oxide suggested that oxidative modifications could play an important role in inhibiting toxicological activity. This study provides a preliminary approach for understanding the environmental behaviors of graphene and avoids overestimating the risks of graphene in the natural environment.
- Published
- 2015
25. Humic Acid Acts as a Natural Antidote of Graphene by Regulating Nanomaterial Translocation and Metabolic Fluxes in Vivo
- Author
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Xiangang Hu, Kaicheng Lu, Ruiren Zhou, Li Mu, Jia Kang, and Qixing Zhou
- Subjects
Chlorophyll ,Antidotes ,Spectrum Analysis, Raman ,Plant Roots ,law.invention ,chemistry.chemical_compound ,law ,Aconitic acid ,Environmental Chemistry ,Humic acid ,Humic Substances ,Triticum ,chemistry.chemical_classification ,Cadaverine ,Graphene ,food and beverages ,Biological Transport ,Oryza ,General Chemistry ,Metabolic Flux Analysis ,Nanostructures ,Phthalic acid ,chemistry ,Biochemistry ,Shoot ,Metabolome ,Graphite ,Phytotoxicity ,Adsorption ,Plant Shoots - Abstract
Graphene-related research has intensified rapidly in a wide range of disciplines, but few studies have examined ecosystem risks, particularly phytotoxicity. This study revealed that graphene significantly inhibits the number of wheat roots and the biosynthesis of chlorophyll, and altered the morphology of shoots. Humic acid (HA), a ubiquitous form of natural organic matter, significantly (P0.05) relieved this phytotoxicity and recovered the sharp morphology of shoot tips. Both graphene and graphene-HA were transferred from wheat roots to shoots and were found in the cytoplasms and chloroplasts. HA increased the disordered structure and surface negative charges, and reduced the aggregation of graphene. HA enhanced the storage of graphene in vacuoles, potentially indicating an effective detoxification path. The content of cadaverine, alkane, glyconic acid, and aconitic acid was up-regulated by graphene, greatly contributing to the observed phytotoxicity. Conversely, inositol, phenylalanine, phthalic acid, and octadecanoic acid were up-regulated by graphene-HA. The metabolic pathway analysis revealed that the direction of metabolic fluxes governed nanotoxicity. This work presents the innovative concept that HA acts as a natural antidote of graphene by regulating its translocation and metabolic fluxes in vivo. This knowledge is critical for avoiding the overestimation of nanomaterial risks and can be used to control nanomaterial contamination.
- Published
- 2014
26. Green Synthesis of Low-Toxicity Graphene-Fulvic Acid with an Open Band Gap Enhances Demethylation of Methylmercury
- Author
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Jia Kang, Qixing Zhou, Kaicheng Lu, Xiangang Hu, and Li Mu
- Subjects
Light ,Band gap ,Inorganic chemistry ,Oxide ,Electrons ,Catalysis ,law.invention ,chemistry.chemical_compound ,Electron transfer ,law ,Microalgae ,Humans ,Benzopyrans ,General Materials Science ,Demethylation ,Mercury Compounds ,Chemistry ,Graphene ,Water ,Oxides ,Mercury ,Methylmercury Compounds ,Reagent ,Photocatalysis ,Graphite - Abstract
The demethylation of methylmercury has received substantial attention. Here, a novel chemical method for the demethylation of methylmercury is proposed. The low-toxicity graphene-fulvic acid (FA, a ubiquitous material in the environment) was synthesized without the use of a chemical reagent. The hybridized graphene-FA presented an indirect open band gap of 2.25-2.87 eV as well as adequate aqueous dispersion. More importantly, the hybridized graphene-FA exhibited 6- and 10-fold higher photocatalytic efficiencies for the demethylation of methylmercury than FA and free FA with graphene, respectively. This result implies that immobilized, rather than free, FA accelerated the catalysis. Furthermore, inorganic mercuric ion, elemental mercury, and mercuric oxide were identified as the primary demethylation products. For free FA with graphene, graphene quenches the excited-state FA, inhibiting the demethylation by electron transfer. In contrast, the graphene of the self-assembled graphene-FA serves as an electron reservoir, causing electron-hole pair separation. Graphene-FA showed a negligible toxicity toward microalgae compared to graphene. The above results reveal that the green synthesis of graphene and organic molecules is a convenient strategy for obtaining effective cocatalysts.
- Published
- 2014
27. Twin-Arginine Signal Peptide of Bacillus subtilis YwbN Can Direct Tat-Dependent Secretion of Methyl Parathion Hydrolase
- Author
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Zhenqiang Zuo, Hong Jiang, Ruihua Liu, Cunjiang Song, Qixing Zhou, Chao Yang, Ping Xu, Chuanling Qiao, and Yingming Xu
- Subjects
Signal peptide ,Arginine ,Molecular Sequence Data ,Mutant ,Bacillus subtilis ,Protein Sorting Signals ,Bacterial Proteins ,Western blot ,mental disorders ,Hydrolase ,medicine ,Secretion ,Bacterial Secretion Systems ,Base Sequence ,biology ,medicine.diagnostic_test ,General Chemistry ,biology.organism_classification ,Molecular biology ,Phosphoric Monoester Hydrolases ,Transport protein ,Protein Transport ,Biochemistry ,General Agricultural and Biological Sciences ,human activities - Abstract
The twin-arginine translocation (Tat) pathway exports folded proteins across the cytoplasmic membranes of bacteria and archaea. Two parallel Tat pathways (TatAdCd and TatAyCy systems) with distinct substrate specificities have previously been discovered in Bacillus subtilis. In this study, to secrete methyl parathion hydrolase (MPH) into the growth medium, the twin-arginine signal peptide of B. subtilis YwbN was used to target MPH to the Tat pathway of B. subtilis. Western blot analysis and MPH assays demonstrated that active MPH was secreted into the culture supernatant of wild-type cells. No MPH secretion occurred in a total-tat2 mutant, indicating that the observed export in wild-type cells was mediated exclusively by the Tat pathway. Export was fully blocked in a tatAyCy mutant. In contrast, the tatAdCd mutant was still capable of secreting MPH. These results indicated that the MPH secretion directed by the YwbN signal peptide was specifically mediated by the TatAyCy system. The N-terminal sequence of secreted MPH was determined as AAPQVR, demonstrating that the YwbN signal peptide had been processed correctly. This is the first report of functional secretion of a heterologous protein via the B. subtilis TatAyCy system. This study highlights the potential of the TatAyCy system to be used for secretion of other heterologous proteins in B. subtilis.
- Published
- 2014
28. Evaluation of Cadmium Phytoremediation Potential in Chinese Cabbage Cultivars
- Author
-
Zhineng Zhang, Qixing Zhou, Weitao Liu, Zhang Cai, and Tao Hua
- Subjects
Cadmium ,Irrigation ,Chemistry ,chemistry.chemical_element ,Bioconcentration ,Brassica ,General Chemistry ,Contamination ,Phytoremediation ,Biodegradation, Environmental ,Agronomy ,Soil water ,Shoot ,Soil Pollutants ,Cultivar ,General Agricultural and Biological Sciences - Abstract
Selecting a phytoextraction plant with moderate to high Cd-accumulating ability and high biomass based on the plant’s compatibility with mechanized cultivation techniques may yield more immediately practical results. In the present study, six Chinese cabbage cultivars were grown in three soils, ranging from 0.15 to 2.25 mg Cd kg–1 soil, to examine uptake and translocation of Cd in their tissues. The results indicated that the order of the shoot Cd concentration values in the cultivars was as follows: Beijingxiaoza 56 > Suancaiwang > Quansheng and Qiubo 60 > Xianfengkuaicai and Chunkang. Similar order was also found in the bioaccumulation factor (BAF), translocation factor (TF), and metal extraction ratio (MER). Several soil Cd fractions after Beijingxiaoza 56 harvesting decreased most. Beijingxiaoza 56 is thus promising for phytoextraction of Cd from soils with low to moderate (
- Published
- 2011
29. Characterization of Alginase and Elicitor-Active Oligosaccharides from Gracilibacillus A7 in Alleviating Salt Stress for Brassica campestris L
- Author
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Jingchun Tang, Qixing Zhou, Shinichi Nagata, and Hongrui Chu
- Subjects
biology ,Brassica ,Oligosaccharides ,Gracilibacillus ,General Chemistry ,Degree of polymerization ,biology.organism_classification ,Malondialdehyde ,Polymerization ,Elicitor ,Superoxide dismutase ,Lipid peroxidation ,Kinetics ,chemistry.chemical_compound ,Point of delivery ,Bacterial Proteins ,Biochemistry ,chemistry ,Stress, Physiological ,biology.protein ,Salts ,General Agricultural and Biological Sciences ,Bacillaceae ,Polysaccharide-Lyases - Abstract
Alginase was purified from Gracilibacillus A7 and evaluated for its ability to produce elicitor-active oligosaccharides. The optimum conditions for the alginase reaction are as follows: temperature, 40 °C; pH, 8.0; alginate content, 0.3-0.7%; and the presence of Na(+) and Mg(2+) metal ions. The degree of polymerization (DP) decreased as the reaction time of the alginase progressed, achieving values of 5.4 and 3.3 after 240 and 300 min, respectively. The relative root length (RRL) of the Brassica campestris L. increased with the addition of oligosaccharides with reduced DP values. The oligosaccharides with lower DP values are effective in reducing the effect of salt stress on the activity of the superoxide dismutase (SOD) and guaiacol peroxidase (POD), and oligosaccharides with moderate DP values can reduce the increase in lipid peroxidation activities (as malondialdehyde content) induced by salt stress. These results suggest that oligosaccharides may act as osmoprotective agents during the plant germination process.
- Published
- 2011
30. Trends in Antibiotic Resistance Genes Occurrence in the Haihe River, China
- Author
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Lin Xu, Pedro J. J. Alvarez, Hongjie Zhang, Yi Luo, Michal Rysz, Daqing Mao, and Qixing Zhou
- Subjects
Hydrology ,China ,Veterinary medicine ,Tetracycline ,Chemistry ,Sediment ,Drug Resistance, Microbial ,General Chemistry ,Drug resistance ,DNA, Ribosomal ,Polymerase Chain Reaction ,Anti-Bacterial Agents ,Chine ,Tandem Mass Spectrometry ,RNA, Ribosomal, 16S ,medicine ,Environmental Chemistry ,Water quality ,Water Microbiology ,Relative species abundance ,Surface water ,Chromatography, High Pressure Liquid ,Water Pollutants, Chemical ,Antibiotic resistance genes ,medicine.drug - Abstract
The occurrence of antibiotics and antibiotic resistance genes (ARGs) was quantified in water and sediment samples collected from a 72 km stretch of the Haihe River, China. Tetracycline resistance genes (tetW, tetQ, tetO, tetT, tetM, tetB, and tetS) were not detected by quantitative PCR in many samples. In contrast, sul1 and sul2 (coding for sulfonamide resistance) were present at relatively high concentrations in all (38) samples. The highest ARG concentrations detected were (7.8 ± 1.0) × 10(9) copies/g for sul1 and (1.7 ± 0.2) × 10(11) copies/g for sul2, in sediment samples collected during the summer. The corresponding total bacterial concentration (quantified with a universal 16S-rDNA probe) was (3.3 ± 0.4) × 10(12) cells/g. Sul1 and sul2 concentrations in sediments were 120-2000 times higher than that in water, indicating that sediments are an important ARG reservoir in the Haihe River. Statistical analysis indicated a positive correlation between the relative abundance of these ARGs (i.e., sul1/16S-rDNA and sul2/16S-rDNA) and the total concentration of sulfamethoxazole, sulfadiazine, plus sulfachlororyridazine, suggesting that sulfonamides exerted selective pressure for these ARGs. A class 1 integron was implicated in the propagation of sul1. Overall, the widespread distribution of sulfonamide ARGs underscores the need to better understand and mitigate their propagation in the environment and the associated risks to public health.
- Published
- 2010
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