Silver nanoparticle （SNP） is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar grow...Silver nanoparticle （SNP） is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs - B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy （FT-IR） peaks for the exopolysaccharides extracted from the bacterial culture supernatant and＇the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray diffraction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanopartieles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.展开更多
The current study evaluates the cytogenetic effects of chromium（Ⅲ） oxide nanoparticles on the root cells of Allium cepa.The root tip cells of A.cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles...The current study evaluates the cytogenetic effects of chromium（Ⅲ） oxide nanoparticles on the root cells of Allium cepa.The root tip cells of A.cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles（NPs） at five different concentrations（0.01,0.1,1,10,and 100 μg/m L） for 4 hr.The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses.After 4 hr exposure to Cr2O3 NPs,a significant decrease in mitotic index（MI） from 35.56%（Control） to 35.26%（0.01 μg/m L）,34.64%（0.1 μg/m L）,32.73%（1 μg/m L）,29.6%（10 μg/m L） and 20.92%（100 μg/m L） was noted.The optical,fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as-chromosome stickiness,chromosome breaks,laggard chromosome,clumped chromosome,multipolar phases,nuclear notch,and nuclear bud at different exposure concentrations.The concentration-dependent internalization/bio-uptake of Cr2O3 NPs may have contributed to the enhanced production of anti oxidant enzyme,superoxide dismutase to counteract the oxidative stress,which in turn resulted in observed chromosomal aberrations and cytogenetic effects.These results suggest that A.cepa root tip assay can be successfully applied for evaluating environmental risk of Cr2O3 NPs over a wide range of concentrations.展开更多
Due to the COVID-19 pandemic, disposable face masks have become a significant source of microplastic pollution in marine ecosystems. Diatoms, as primary producers are often used as model organism for aquatic toxicity ...Due to the COVID-19 pandemic, disposable face masks have become a significant source of microplastic pollution in marine ecosystems. Diatoms, as primary producers are often used as model organism for aquatic toxicity assessments. Only a limited number of studies have examined the toxicity of mask leachate (ML) on diatoms. However, the toxicity mechanism of ML released at different time intervals is underexplored. Furthermore, the role of extracellular polymeric substances (EPS) in modulating ML toxicity is also poorly understood. To address these gaps, we investigated the toxicity of ML from three time intervals (1-day, 14-day, and 21-day) on the marine diatom Chaetoceros sp., finding that toxicity increased with time: 21-day ML > 14-day ML > 1-day ML. To assess the toxicity, we have estimated chlorophyll pigment levels, reactive oxygen species, and malondialdehyde levels. Furthermore, the presence of heavy metals in the ML was analyzed using Inductively Coupled Plasma Mass Spectrometry. Our results suggest that increased ROS production is a crucial mechanism of toxicity, while EPS reduces toxic effects compared to pristine ML. The interaction of EPS with ML was analyzed using Fourier-Transform Infrared Spectroscopy and 3D-Excitation Emission Matrix spectroscopy. Pearson correlation and heatmap were used to assess the correlations between toxicity endpoints. This study provides critical insights into the environmental impact of ML on marine diatoms and highlights the role of EPS in mitigating ML toxicity.展开更多
In this study,FeNi nanoparticles were green synthesized using Punica granatum(pomegranate)peel extract,and these nanoparticles were also formed in situ over quartz sand(GS-FeNi)for removal of tetracycline(TC).Under th...In this study,FeNi nanoparticles were green synthesized using Punica granatum(pomegranate)peel extract,and these nanoparticles were also formed in situ over quartz sand(GS-FeNi)for removal of tetracycline(TC).Under the optimized operating conditions,(GS-FeNi concentration:1.5%w/v;concentration of TC:20 mg/L;interaction period:180 min),99±0.2%TC removal was achieved in the batch reactor The removaT capacity was 181±1 mg/g.A detailed characterization of the sorbent and the solution before and after the interaction revealed that the removal mechanism(s)involved both the sorption and degradation of TC.The reusability of reactant was assessed for four cycles of operation,and 77±4%of TC removal was obtained in the cycle.To judge the environmental sustainability of the process,residual toxicity assay of the interacted TC solution was performed with indicator bacteria(Bacillus and Pseudomonas)and algae(Chlorella sp.),which confirmed a substantial decrease in the toxicity.The continuous column studies were undertaken in the packed bed reactors using GS-FeNi.Employing the optimized conditions,quite high removal efficiency(978±5 mg/g)was obtained in the columns.The application of GS-FeNi for antibiotic removal was further evaluated in lake water,tap water,and ground water spiked with TC,and the removal capacity achieved was found to be 781±5,712±5,and 687±3 mg/g,respectively.This work can pave the way for treatment of antibiotics and other pollutants in the reactors using novel green composites prepared from fruit wastes.展开更多
Usage of titanium dioxide nanoparticles(TiO_(2) NPs)and tetracycline(TC)has increased significantly in the present era.This leads to their release and accumulation in the environment.Both the compounds,individually,ca...Usage of titanium dioxide nanoparticles(TiO_(2) NPs)and tetracycline(TC)has increased significantly in the present era.This leads to their release and accumulation in the environment.Both the compounds,individually,can have adverse toxic effects on the plants.Their binary mixtures can increase this degree of damage.The present study aimed to evaluate the toxicity of both the contaminants in individual and binary mixtures in Allium cepa.Further,the toxicity of TiO_(2) NPs upon UVA pre-irradiation was also measured.Results showed that UVA pre-irradiated NPs(UVA-TiO_(2) NPs)had a significant decrease in cell viability than their non-irradiated counterparts(NI-TiO_(2)),denoting an increase in photocatalytic activity upon UVA pre-irradiation.Very low concentrations of TC(EC10=0.016µmol/L)mixed with TiO2 NPs significantly increased the toxicity for both UVA-TiO_(2) and NI-TiO_(2) NPs.Intracellular ROS generation was significantly high for UVA-TiO_(2) NPs.However,TC did not have any effects on ROS production.Both the compounds exhibited genotoxic potential in A.cepa.Different chromosomal abnormalities like anaphase bridges,telophase bridges,laggard chromosomes,binucleate cells,etc.were observed.The binary mixture of UVA-TiO_(2) NPs and TC showed the highest chromosomal aberrations(64.0%±1.26%)than the mixture with NI-TiO_(2) or the individual contaminants.This decreased significantly after recovery(46.8%±1.92%),denoting the self-repair processes.This study proved that UVA-TiO2 NPs were more toxic and could be enhanced further when mixed with a sub-lethal concentration of TC.This work will help to assess the risk of both compounds in the environment.展开更多
The Asia-Pacific region now faces another year of slowing growth, but the region will remain the anchor of global economic stability, said a UN Economic and Social Commission for Asia and the Pacific (ESCAP) survey re...The Asia-Pacific region now faces another year of slowing growth, but the region will remain the anchor of global economic stability, said a UN Economic and Social Commission for Asia and the Pacific (ESCAP) survey released in May. In a recent interview with Beijing Review,展开更多
基金VIT University Chancellor for providing us with funding to carry out our research
文摘Silver nanoparticle （SNP） is a threat to soil, water and human health. Protection of environment from silver nanoparticles is a major concern. A sewage isolate, Bacillus pumilus treated with SNPs showed similar growth kinetics to that without nanoparticles. A reduction in the amount of exopolysaccharides was observed after SNPs - B. pumilus culture supernatant interaction. The Fourier transform infrared spectroscopy （FT-IR） peaks for the exopolysaccharides extracted from the bacterial culture supernatant and＇the interacted SNPs were almost similar. The exopolysaccharide capping of the SNPs was confirmed by UV-Visible, FT-IR and X-ray diffraction analysis. The study of bacterial exopolysaccharides capped SNPs with E. coli, S. aureus and M. luteus showed less toxicity compared to uncoated SNPs. Our studies suggested that the capping of nanopartieles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.
文摘The current study evaluates the cytogenetic effects of chromium（Ⅲ） oxide nanoparticles on the root cells of Allium cepa.The root tip cells of A.cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles（NPs） at five different concentrations（0.01,0.1,1,10,and 100 μg/m L） for 4 hr.The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses.After 4 hr exposure to Cr2O3 NPs,a significant decrease in mitotic index（MI） from 35.56%（Control） to 35.26%（0.01 μg/m L）,34.64%（0.1 μg/m L）,32.73%（1 μg/m L）,29.6%（10 μg/m L） and 20.92%（100 μg/m L） was noted.The optical,fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as-chromosome stickiness,chromosome breaks,laggard chromosome,clumped chromosome,multipolar phases,nuclear notch,and nuclear bud at different exposure concentrations.The concentration-dependent internalization/bio-uptake of Cr2O3 NPs may have contributed to the enhanced production of anti oxidant enzyme,superoxide dismutase to counteract the oxidative stress,which in turn resulted in observed chromosomal aberrations and cytogenetic effects.These results suggest that A.cepa root tip assay can be successfully applied for evaluating environmental risk of Cr2O3 NPs over a wide range of concentrations.
文摘Due to the COVID-19 pandemic, disposable face masks have become a significant source of microplastic pollution in marine ecosystems. Diatoms, as primary producers are often used as model organism for aquatic toxicity assessments. Only a limited number of studies have examined the toxicity of mask leachate (ML) on diatoms. However, the toxicity mechanism of ML released at different time intervals is underexplored. Furthermore, the role of extracellular polymeric substances (EPS) in modulating ML toxicity is also poorly understood. To address these gaps, we investigated the toxicity of ML from three time intervals (1-day, 14-day, and 21-day) on the marine diatom Chaetoceros sp., finding that toxicity increased with time: 21-day ML > 14-day ML > 1-day ML. To assess the toxicity, we have estimated chlorophyll pigment levels, reactive oxygen species, and malondialdehyde levels. Furthermore, the presence of heavy metals in the ML was analyzed using Inductively Coupled Plasma Mass Spectrometry. Our results suggest that increased ROS production is a crucial mechanism of toxicity, while EPS reduces toxic effects compared to pristine ML. The interaction of EPS with ML was analyzed using Fourier-Transform Infrared Spectroscopy and 3D-Excitation Emission Matrix spectroscopy. Pearson correlation and heatmap were used to assess the correlations between toxicity endpoints. This study provides critical insights into the environmental impact of ML on marine diatoms and highlights the role of EPS in mitigating ML toxicity.
基金We wholeheartedly thank the Department of Science and Technology-Science and Engineering Research Board(DST-SERB)Organization(Sanction No.EMR72016/004816)for providing the financial support for carrying out this research work.We would also express sincere gratitude to Dr.Sruthi Ann Alex,Teaching fellow,Centre for Nano Science and Technology,ACTECH-Anna University,Chennai for her help in proof reading the manuscript.
文摘In this study,FeNi nanoparticles were green synthesized using Punica granatum(pomegranate)peel extract,and these nanoparticles were also formed in situ over quartz sand(GS-FeNi)for removal of tetracycline(TC).Under the optimized operating conditions,(GS-FeNi concentration:1.5%w/v;concentration of TC:20 mg/L;interaction period:180 min),99±0.2%TC removal was achieved in the batch reactor The removaT capacity was 181±1 mg/g.A detailed characterization of the sorbent and the solution before and after the interaction revealed that the removal mechanism(s)involved both the sorption and degradation of TC.The reusability of reactant was assessed for four cycles of operation,and 77±4%of TC removal was obtained in the cycle.To judge the environmental sustainability of the process,residual toxicity assay of the interacted TC solution was performed with indicator bacteria(Bacillus and Pseudomonas)and algae(Chlorella sp.),which confirmed a substantial decrease in the toxicity.The continuous column studies were undertaken in the packed bed reactors using GS-FeNi.Employing the optimized conditions,quite high removal efficiency(978±5 mg/g)was obtained in the columns.The application of GS-FeNi for antibiotic removal was further evaluated in lake water,tap water,and ground water spiked with TC,and the removal capacity achieved was found to be 781±5,712±5,and 687±3 mg/g,respectively.This work can pave the way for treatment of antibiotics and other pollutants in the reactors using novel green composites prepared from fruit wastes.
文摘Usage of titanium dioxide nanoparticles(TiO_(2) NPs)and tetracycline(TC)has increased significantly in the present era.This leads to their release and accumulation in the environment.Both the compounds,individually,can have adverse toxic effects on the plants.Their binary mixtures can increase this degree of damage.The present study aimed to evaluate the toxicity of both the contaminants in individual and binary mixtures in Allium cepa.Further,the toxicity of TiO_(2) NPs upon UVA pre-irradiation was also measured.Results showed that UVA pre-irradiated NPs(UVA-TiO_(2) NPs)had a significant decrease in cell viability than their non-irradiated counterparts(NI-TiO_(2)),denoting an increase in photocatalytic activity upon UVA pre-irradiation.Very low concentrations of TC(EC10=0.016µmol/L)mixed with TiO2 NPs significantly increased the toxicity for both UVA-TiO_(2) and NI-TiO_(2) NPs.Intracellular ROS generation was significantly high for UVA-TiO_(2) NPs.However,TC did not have any effects on ROS production.Both the compounds exhibited genotoxic potential in A.cepa.Different chromosomal abnormalities like anaphase bridges,telophase bridges,laggard chromosomes,binucleate cells,etc.were observed.The binary mixture of UVA-TiO_(2) NPs and TC showed the highest chromosomal aberrations(64.0%±1.26%)than the mixture with NI-TiO_(2) or the individual contaminants.This decreased significantly after recovery(46.8%±1.92%),denoting the self-repair processes.This study proved that UVA-TiO2 NPs were more toxic and could be enhanced further when mixed with a sub-lethal concentration of TC.This work will help to assess the risk of both compounds in the environment.
文摘The Asia-Pacific region now faces another year of slowing growth, but the region will remain the anchor of global economic stability, said a UN Economic and Social Commission for Asia and the Pacific (ESCAP) survey released in May. In a recent interview with Beijing Review,
