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1.
J Hazard Mater ; 423(Pt A): 127088, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34482077

RESUMO

Antibiotic resistance has become a global public health problem. Recently, various environmental pollutants have been reported to induce the proliferation of antibiotic resistance. However, the impact of multiple pollutants (e.g., heavy metals and antibiotics), which more frequently occur in practical environments, is poorly understood. Herein, one widely distributed heavy metal (Ag+) and one frequently detected antibiotic (tetracycline) were chosen to investigate their coexisting effect on the proliferation of antibiotic resistance in the activated sludge system. Results show that the co-occurrence of Ag+ and tetracycline at environmentally relevant concentrations exhibited no distinct inhibition in reactor performances. However, they inhibited the respiratory activity by 42%, destroyed the membrane structure by 218%, and increased membrane permeability by 29% compared with the blank control bioreactor. Moreover, the relative abundances of target antibiotic resistance genes (ARGs) (e.g., tetA, blaTEM-1, and sulII) in effluent after exposure of coexisting Ag+ and tetracycline were increased by 92-1983% compared with those in control reactor, which were 1.1-4.3 folds higher than the sum of the sole ones. These were possibly attributed to the enrichments of antibiotic-resistant bacteria. The results would illumine the coexisting effect of heavy metals and antibiotics on the dissemination of ARGs in activated sludge system.

2.
Sci Total Environ ; : 151575, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34767888

RESUMO

Wastewater treatment plants (WWTPs) are important sources of antibiotic resistance genes (ARGs). Increasing attention has been paid to extracellular ARGs in cell-free form due to their horizontal gene transfer via transformation. However, the fate of the adsorbed form of extracellular ARGs that exist in extracellular polymeric substances (EPS) of activated sludge in WWTP remains largely unknown. Herein, seven EPS-associated ARGs along the anaerobic-anoxic-aerobic (AAO) process were quantified using quantitative polymerase chain reaction. Results show that the absolute abundances of EPS-associated ARGs were 0.69-4.52 logs higher than those of cell-free ARGs. There was no significant difference in the abundances of EPS-associated ARGs along the AAO process. Among these target genes, the abundances of EPS-associated sul genes were higher than those of EPS-associated tet and bla genes. Proteobacteria and Bacteroidetes were identified as the major secretors of EPS-associated ARGs, and they may play an important role in the proliferation of extracellular ARGs. Moreover, the transformation efficiencies of EPS-associated ARGs were 3.55-4.65 logs higher than those of cell-free ARGs, indicating that EPS-associated ARGs have higher environmental risks. These findings have advanced our understanding of EPS-associated ARGs and are useful for the control and risk assessment of ARGs in WWTPs.

3.
J Hazard Mater ; 416: 125865, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492813

RESUMO

Anaerobic biological treatment technologies are one of the major hotspots of antibiotic resistance genes (ARGs). Previous studies have applied the electrochemical process to improve biogas production, however, it was challenged that high voltages might promote membrane permeability and reactive oxygen species overproduction to promote ARGs proliferation. Herein, the biogas production and ARGs proliferation in an anaerobic electrochemical membrane bioreactor (AnEMBR) were investigated at the gradient voltages of 0-0.9 V. Results show the reactor performances (average CH4 production and current generation) were distinctly improved with the increase of applied voltage, and reached the optimum at 0.9 V. However, long-term application (>30 day) of 0.9 V deteriorated the reactor performances. Meanwhile, the relative abundances of most target ARGs in the supernatant and effluent of AnEMBR at 0.9 V increased by 0.68-1.55 and 0.42-1.26 logs compared to those before applying voltage, respectively. After disconnecting the circuit, these ARGs abundances all decreased to the original level. Significant correlations between intlI and ARGs (e.g., tetA, tetQ, sulI, and sulII) were observed, indicating horizontal gene transfer may contribute to the increased ARGs. Moreover, the shift of microbial communities caused by the applied voltage enriched potential ARGs-hosts (e.g., Tolumonas), contributing to the proliferation of ARGs.


Assuntos
Antibacterianos , Biocombustíveis , Anaerobiose , Antibacterianos/farmacologia , Reatores Biológicos , Proliferação de Células , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos
4.
J Hazard Mater ; 420: 126672, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329092

RESUMO

Earthworms have shown their effectiveness in reducing the abundances of antibiotic resistance genes (ARGs) from solid waste. However, the mechanisms of the reduced ARGs by earthworm and whether the solid waste would affect the ARGs profile in earthworm gut were poorly understood. Herein, the patterns of ARGs and microbial communities in digested sludge-amended soil and earthworm gut after 80-day cultivation were investigated. Results show that the enrichment of ARGs (e.g., tetA, tetQ, and sulII) in soil caused by digested sludge-amendment was temporary and would recover to their original levels before amendment. In addition, earthworms could contribute to the further reduction of ARG abundances, which was mainly attributed to their gut digestion via shifting the microbial community (e.g., attenuating the anaerobes). However, the amended soil could significantly increase ARGs abundance in the earthworm gut, which may enhance the potential risk of ARGs spread via the food chain. These findings may provide a new sight on the control of ARGs occurrence and dissemination in sludge-amended soil ecosystem with consideration of earthworms.


Assuntos
Microbiota , Solo , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Esgotos
5.
J Hazard Mater ; 408: 124428, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33160787

RESUMO

Antibiotic resistance has been regarded as a global concern and biological wastewater treatment plants (WWTPs) are ideal hotbeds for the emergence and propagation of antibiotic resistance genes (ARGs). Extracellular polymeric substances (EPS), one of the primary components of activated sludge, might affect the distribution of extracellular ARGs in supernatant and EPS matrix, and thus alter their uptake potential by microbial cells. Herein, the presence and significance of EPS-associated ARGs in activated sludge from four WWTPs were assessed. Seven typical ARGs (sulI, sulII, blaTEM-1, tetA, tetO, tetQ, tetW) and class I integron (intI1) in EPS-associated, cell-free, and intracellular DNA were quantified. Results show that the absolute abundances of EPS-associated, cell-free, and intracellular ARGs were 5.90 × 106-6.45 × 109, 5.53 × 104-4.58 × 106, and 2.68 × 108-1.79 × 1011 copies/g-volatile suspended solids, respectively. The absolute abundances of EPS-associated ARGs were 0.2-4.6 orders of magnitude higher than those of the corresponding cell-free ARGs. Considering the higher DNA contents in EPS, the transformation abilities of EPS-associated ARGs were 3.3-236.3 folds higher than those of cell-free ARGs. Therefore, EPS-associated ARGs are an important source of extracellular ARGs, and it may play a crucial role in horizontal gene transfer via transformation in WWTPs.


Assuntos
Matriz Extracelular de Substâncias Poliméricas , Esgotos , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos/genética , Matriz Extracelular de Substâncias Poliméricas/genética , Genes Bacterianos , Águas Residuárias
6.
PeerJ ; 8: e9724, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32864222

RESUMO

Forchlorfenuron, N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU), is often used to promote fruit growth and improve production. The role of CPPU in kiwifruit growth has been established. However, the correlation between fruit weight and nutritional metabolism during development after CPPU treatments remains largely undetermined. Here, we surveyed the variations in weight and nutrient components of the 'Hongyang' kiwifruit (Actinidia chinensis) when CPPU was sprayed on fruit 25 days after anthesis. The CPPU application did not significantly influence the dry matter, soluble solids, starch, vitamin C or protein concentrations. However, the fresh weight, length and maximum diameter were significantly increased compared with the control. Moreover, in fruit of the same developmental stage, the fructose, glucose and soluble sugar levels increased after the CPPU treatment, compared with the control. On the contrary, citric, quinic and titratable acid concentrations decreased. However, a correlation analysis between fresh weight and the nutritional contents revealed that CPPU did not affect the concentrations of the most abundant organic acids (quinic and citric) and sugars (glucose, fructose and sucrose), compared with control fruit of the same weight. Therefore, CPPU applications enhance 'Hongyang' kiwifruit weight/size. However, there were no significant differences in the nutritional qualities of treated and untreated fruit having the same weights.

7.
Environ Pollut ; 255(Pt 2): 113327, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31600703

RESUMO

Fish-associated antibiotic resistance genes (ARGs) have attracted increasing attention due to their potential risks to human beings via the food chain. However, data are scarce regarding the antibiotic resistance in fish themselves. Herein, the antibiotic resistance genes (ARGs) were assessed in the gut of four major Chinese freshwater carp (i.e., silver carp, grass carp, bighead carp, and crucian carp) from food retail markets. Results show that the abundances of target ARGs (e.g., tetA, tetO, tetQ, tetW, sulI, sulII, and blaTEM-1) and class 1 integrase (intI1) were in the range 9.4 × 10-6 - 1.6 × 10-1 and 6.7 × 10-5 - 5.2 × 10-2 gene copies per 16S rRNA gene, respectively. The sulI, sulII, and tetQ strongly correlated with silver and mercury resistance genes (e.g., silE and merR). The microbial taxa of fish gut could be partly separated among retail markets based on the PCA analysis. About 15.0% of the OTUs in fish gut were shared and 74.5% of the shared OTUs were identified as Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, and Proteobacteria. These phyla may constitute the core microbiota in the guts of the four Chinese freshwater carp. The possible ARG hosts were revealed based on the network analysis, and the presence of pathogen-associated resistant genera in fish gut highlights the need to fully understand their potential human health risks.


Assuntos
Carpas/microbiologia , Farmacorresistência Bacteriana/genética , Microbioma Gastrointestinal/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Acidobacteria/efeitos dos fármacos , Acidobacteria/genética , Acidobacteria/isolamento & purificação , Animais , Antibacterianos/farmacologia , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Chloroflexi/efeitos dos fármacos , Chloroflexi/genética , Chloroflexi/isolamento & purificação , Cianobactérias/efeitos dos fármacos , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Firmicutes/efeitos dos fármacos , Firmicutes/genética , Firmicutes/isolamento & purificação , Água Doce/microbiologia , Microbioma Gastrointestinal/genética , Genes Bacterianos/genética , Metais Pesados/toxicidade , Proteobactérias/efeitos dos fármacos , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética
8.
Environ Int ; 130: 104902, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31228781

RESUMO

The aerobic granular sludge with larger size and more compact spherical structure generally shows excellent performance in antibiotic removal, yet little is known about the long-term effect of environmentally-relevant concentration (µg/L) of antibiotics on the proliferation of antibiotic resistance genes (ARGs) and microbial community in aerobic granules. Herein, a sequencing batch reactor (SBR) was set up with dosing different concentrations (0-500 µg/L) of tetracycline to investigate its influences on microbial communities and ARG levels in aerobic granular sludge. Results show that the bioreactor could effectively remove chemical oxygen demand (COD), nitrogen, and tetracycline during the long-term operation. The quantitative polymerase chain reaction (qPCR) analysis shows that tetracycline at µg/L level could greatly enhance the absolute and relative abundances of tetA, sulII, and blaTEM-1 in the effluent and aerobic granules, indicating tetracycline could serve as a selection pressure on the development of ARGs corresponding to different types of antibiotics in aerobic granules. Pearson's correlation analysis also implies that sulII and blaTEM-1 were correlated strongly with tetA. Moreover, the presence of tetracycline altered the microbial communities and diversity of the effluent and aerobic granules in the bioreactor. These findings would advance our understanding of the proliferation and development of ARGs in aerobic granules under tetracycline pressure and serve as a foundation to guide the application of aerobic granular sludge for treatment of antibiotic-containing wastewater.


Assuntos
Resistência Microbiana a Medicamentos/genética , Genes Bacterianos/genética , Microbiota , Esgotos/microbiologia , Tetraciclina/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , Monitoramento Ambiental , Microbiota/efeitos dos fármacos , Microbiota/genética
9.
Water Res ; 159: 145-152, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31085389

RESUMO

Antibiotic resistance genes (ARGs) have been regarded as an emerging pollutant in municipal wastewater treatment plant (WWTP) effluents due to their potential risk to human health and ecological safety when reused for landscape and irrigation. Conventional wastewater treatment processes generally fail to effectively reduce ARGs, especially extracellular ARGs (eARGs), which are persistent in the environment and play an important role in horizontal gene transfer via transformation. Herein, an integrated process of pre-coagulation and microfiltration was developed for removal of ARGs, especially eARGs, from wastewater effluent. Results show that the integrated process could effectively reduce the absolute abundances of total ARGs (tARGs) (>2.9 logs) and eARGs (>5.2 logs) from the effluent. The excellent performance could be mainly attributed to the capture of antibiotic resistant bacteria (ARB) and eARGs by pre-coagulation and co-rejection during subsequent microfiltration. Moreover, the integrated process exhibited a good performance on removing common pollutants (e.g., dissolved organic carbon and phosphate) from the effluent to improve water quality. Besides, the integrated process also greatly reduced membrane fouling compared with microfiltration. These findings suggest that the integrated process of pre-coagulation and microfiltration is a promising advanced wastewater treatment technology for ARGs (especially eARGs) removal from WWTP effluents to ensure water reuse security.


Assuntos
Antibacterianos , Águas Residuárias , Bactérias , Resistência Microbiana a Medicamentos , Genes Bacterianos , Humanos
10.
Sci Total Environ ; 657: 1014-1022, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30677869

RESUMO

Municipal wastewater treatment plants (WWTPs) are an important reservoir for heavy metal (e.g., Hg and Ag) resistance genes and antibiotic resistance genes (ARGs). However, current knowledge on Hg/Ag resistance genes and their association with ARGs in WWTPs remains largely unknown. In this study, the fates of five Hg/Ag resistance genes (merB, merD, merR, silE, and silR), five ARGs (sulI, sulII, tetO, tetQ, tetW), and class 1 integrase (intI1) in a WWTP were investigated. Results show that the absolute abundances of all target genes were greatly reduced through the treatment systems. The dynamics of merB, merD and silE were significantly correlated with tetW and sulII. Based on network analysis, Hg/Ag resistance genes might share the same microbial hosts with tetQ and tetW, implying the potential importance of Hg/Ag in ARGs evolution and spread. These findings advanced our understanding of the occurrence of Hg/Ag resistance genes and ARGs in WWTPs.


Assuntos
Resistência Microbiana a Medicamentos/genética , Mercúrio/farmacologia , Microbiota/genética , Prata/farmacologia , Eliminação de Resíduos Líquidos/métodos , Proteínas de Bactérias/genética , Reatores Biológicos/microbiologia , Proteínas de Transporte/genética , China , Proteínas de Ligação a DNA/genética , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Filtração , Halogenação , Liases/genética , Microbiota/efeitos dos fármacos , Águas Residuárias/microbiologia , Áreas Alagadas
11.
Sheng Li Xue Bao ; 69(6): 817-829, 2017 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-29270598

RESUMO

Myelin is a highly specialized membrane structure, wrapping around the axons. It is essential for the protection of axons, insulation and maintenance of the saltatory conduction of the action potential. Myelin membrane is rich in lipids, however, the lipid composition varies significantly from other biological membranes. Since myelination requires extraordinarily high level of lipid synthesis, the integrity of myelin is susceptible to numerous lipid metabolism disorders. Studies on transgenic mice targeting key molecules of various lipid biosynthesis pathways have elucidated the lipid metabolism and functions of myelin. Besides, myelinating glial cells have a remarkable capacity to take up extracellular lipids, which also contributes to myelination. Therefore, understanding the metabolism and functions of myelin lipids will help us to understand the role of lipids in myelin damage-related diseases and provide novel strategies for the treatment of demyelinating diseases. In this paper, some progresses in metabolism and functions of myelin lipids are reviewed.


Assuntos
Metabolismo dos Lipídeos , Bainha de Mielina/fisiologia , Animais , Humanos
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