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Antibiotic resistance can be transferred into the food chain, leading to increased risks to human health from ready-to-eat vegetables. Mitigating the transmission of antibiotic resistance from soil to vegetables by green materials is of great significance. Here, we deciphered the roles of biochar and theaflavins in mitigating antibiotic resistance genes (ARGs) and antibiotic-resistant pathogens (ARPs) in a soil-lettuce continuum. Metagenomic results showed that biochar led to a significant decrease in the abundance of ARGs in lettuce leaves, while theaflavins contributed to a significant reduction in the diversity and abundance of ARGs in soil, particularly targeting dominant ARG types such as sulfonamide and aminoglycoside resistance genes. Meanwhile, biochar and theaflavins alleviated the potential mobility of ARGs, in lettuce leaves and soil, respectively, including the spread of ARGs to human pathogens. In addition, the diversity of ARG hosts was reduced in the soil-lettuce continuum and ARPs were not detected in lettuce leaves after the application of biochar or theaflavins. Overall, this study provides a novel perspective on green materials for mitigating the antibiotic resistome and ARPs in the soil-lettuce continuum, contributing to food security and human health., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Rapid hemostasis and wound healing are crucial in emergency trauma situations for saving patients' lives. Traditional hemostatic materials often have drawbacks such as slow hemostasis and susceptibility to post-hemostasis bacterial infections. Therefore, there is an urgent need for advanced wound dressing materials that can provide both rapid hemostasis and antimicrobial properties. In this study, we designed and fabricated a biocompatible hemostatic silk fibroin (SF) aerogel loaded with aggregation-induced emission (AIE)-featured berberine (BBr) and Ti 3 C 2 T x MXene. The resulting SFMB aerogel demonstrates robust mechanical properties and a porous structure that enables quick hemostasis. This aerogel exhibits photodynamic and photothermal responses for antimicrobial activity, releases BBr upon light exposure to enhance bacterial-killing efficiency (99.33 % in vitro and 99.09 % in vivo), and effectively promotes the healing of infected wounds in vivo through combined photothermal/photodynamic antibacterial and anti-inflammatory mechanisms. Furthermore, the aerogel shows high hemocompatibility and cytocompatibility, supporting its potential biomedical applications. Overall, the synthesized SFMB aerogel holds promise for treating bacteria-infected wounds and for use in first aid applications in clinical settings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Co-contamination of carbendazim (CBD) and deoxynivalenol (DON) is common in agricultural soils, yet their ecological impact on soil microbiome remains poorly assessed. Here, we investigated the influence of CBD and DON on the structure, function, and co-occurrence networks of soil microbiome. The combined treatment of CBD and DON significantly exacerbated the negative impacts on soil microbial diversity, functional diversity, and microbial network stability compared to individual treatments. Specifically, Lysobacter, Gemmatimonas, Nitrospira, Massilia, and Bacillus were identified as indicator species for CBD and DON. Simultaneously, the abundance of genes involved in key ecological functions, such as nitrification (amoA) and organic phosphorus mineralization (phoAD), was significantly reduced. Notably, key bacterial taxa Nitrospira and Gemmatimonas, with K-life history strategy and capabilities for nitrification and organic nitrogen mineralization, played crucial roles in promoting positive interactions in networks. Furthermore, variance partitioning analysis (VPA) and structural equation modeling (SEM) demonstrated that the abundance and niche breadth of key bacterial taxa were the primary drivers of microbial network stability. In conclusion, our study provides new insights into how soil microbiomes and networks respond to pesticides and mycotoxins, aiding in a more comprehensive assessment of exposure risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The emergence and spread of antibiotic resistance genes (ARGs) have become a serious issue in global agricultural production. However, understanding how these ARGs spread across different spatial scales, especially when exposed to both pesticides and antibiotics, has remained a challenge. Here, metagenomic assembly and binning methodologies were used to determine the spread pathway of ARGs in the soil-lettuce system under individual and combined exposure of fungicides (carbendazim and pyraclostrobin) and antibiotics (chlortetracycline and ciprofloxacin). These agrochemicals not only facilitated the spread of ARGs from soil to lettuce but also significantly elevated the risk of developing multi-antibiotic resistance among bacteria, especially to some antibiotic types (i.e. sulfonamide, aminoglycoside, quinolone, and tetracycline). ARGs could be migrated through distinct pathways, including both vertical and horizontal gene transfer, with plasmids playing a crucial role in facilitating the horizontal gene transfer. These transfer pathways have enabled key pathogenic bacteria belonging to the genera Acinetobacter, Pseudomonas, and Pantoea to acquire resistance and remain recalcitrant, posing the potential risk to crop health and food safety. In summary, our findings highlighted that fungicide and antibiotic could drive upward migration of ARGs in the soil-lettuce system and reduced the quality safety of agricultural products., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The development of antibiotic resistance threatens human and environmental health. Non-antibiotic stressors, including fungicides, may contribute to the spread of antibiotic resistance genes (ARGs). We determined the promoting effects of tebuconazole on ARG dissemination using a donor, Escherichia coli MG1655, containing a multidrug-resistant fluorescent plasmid (RP4) and a recipient (E. coli HB101). The donor was then incorporated into the soil to test whether tebuconazole could accelerate the spread of RP4 into indigenous bacteria. Tebuconazole promoted the transfer of the RP4 plasmid from the donor into the recipient via overproduction of reactive oxygen species (ROS), enhancement of cell membrane permeability and regulation of related genes. The dissemination of the RP4 plasmid from the donor to soil bacteria was significantly enhanced by tebuconazole. RP4 plasmid could be propagated into more genera of bacteria in tebuconazole-contaminated soil as the exposure time increased. These findings demonstrate that the fungicide tebuconazole promotes the spread of the RP4 plasmid into indigenous soil bacteria, revealing the potential risk of tebuconazole residues enhancing the dissemination of ARGs in soil environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Curcumin ameliorates bone loss by inhibiting osteoclastogenesis. Curcumin inhibits RANKL-promoted autophagy in osteoclast precursors (OCPs), which mediates its anti-osteoclastogenic effect. But the role of RANKL signaling in curcumin-regulated OCP autophagy is unknown. This study aimed to explore the relationship between curcumin, RANKL signaling, and OCP autophagy during osteoclastogenesis., Methods: We investigated the role of curcumin in RANKL-related molecular signaling in OCPs, and identified the significance of RANK-TRAF6 signaling in curcumin-treated osteoclastogenesis and OCP autophagy using flow sorting and lentiviral transduction. Tg-hRANKL mice were used to observe the in vivo effects of curcumin on RANKL-regulated bone loss, osteoclastogenesis, and OCP autophagy. The significance of JNK-BCL2-Beclin1 pathway in curcumin-regulated OCP autophagy with RANKL was explored via rescue assays and BCL2 phosphorylation detection., Results: Curcumin inhibited RANKL-related molecular signaling in OCPs, and repressed osteoclast differentiation and autophagy in sorted RANK + OCPs but did not affect those of RANK - OCPs. Curcumin-inhibited osteoclast differentiation and OCP autophagy were recovered by TRAF6 overexpression. But curcumin lost these effects under TRAF6 knockdown. Furthermore, curcumin prevented the decrease in bone mass and the increase in trabecular osteoclast formation and autophagy in RANK + OCPs in Tg-hRANKL mice. Additionally, curcumin-inhibited OCP autophagy with RANKL was reversed by JNK activator anisomycin and TAT-Beclin1 overexpressing Beclin1. Curcumin inhibited BCL2 phosphorylation at Ser70 and enhanced protein interaction between BCL2 and Beclin1 in OCPs., Conclusions: Curcumin suppresses RANKL-promoted OCP autophagy by inhibiting signaling pathway downstream of RANKL, contributing to its anti-osteoclastogenic effect. Moreover, JNK-BCL2-Beclin1 pathway plays an important role in curcumin-regulated OCP autophagy., Competing Interests: Conflicts of interest The authors declare that there is no conflict of interests., (© 2023 Chang Gung University. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

In nature, aquatic organisms may suffer from chemical pollution, together with thermal stress resulted from global warming. However, limited information is available on the combined effects of pesticide with climate change on aquatic organisms. In this study, the acute toxicity of clothianidin to Limnodrilus hoffmeisteri as well as its effect on the induction of oxidative stress under both constant temperature and daily temperature fluctuation (DTF) regimes was investigated. Results showed that clothianidin exhibited the minimal toxicity to L. hoffmeisteri at 25 °C, which was magnified by both increased or decreased temperatures and 10 °C DTF. At different temperatures (15 °C, 25 °C and 35 °C), clothianidin exposure led to the elevated reactive oxygen species (ROS) levels and activated the antioxidant enzymes to resist against the oxidative stress. However, the antioxidant response induced by clothianidin was overwhelmed at high temperature as evidenced by decreased glutathione (GSH) content. Significant elevation of catalase (CAT) and peroxidase (POD) activities but depletion of GSH was also observed in worms treated with clothianidin under DTF after 24 h. The results indicated that high temperature and DTF could aggravate the clothianidin-induced oxidative stress. Moreover, the critical thermal maximum (CT max ) of the worms decreased with the increasing clothianidin concentrations, suggesting that exposure to clothianidin could reduce the heat tolerance of L. hoffmeisteri. Our work highlights the crucial importance to integrate temperature changes into risk assessment of pesticides under global warming., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Earthworms are recognized as carriers of pollutants; however, how fungicide residues affect microbiota and antibiotic resistance genes (ARGs) in earthworm guts has remained unclear. In this work, changes in the earthworm gut microbiome and resistome were investigated after chlorothalonil (CTL) application. Earthworm activity accelerated the dissipation of CTL in soil, while metagenomic analysis revealed that CTL altered the ARG profile, leading to an increased abundance of ARGs in earthworm guts, particularly with respect to ARG subtypes CRP and OXA-427. CTL also reduced bacterial diversity and elevated the relative abundance of the phylum Proteobacteria, including a potential ARG host, Aeromonas, which is a known pathogen. Various bacterial genera from the Actinobacteria and Proteobacteria phyla were identified as broad-spectrum hosts for ARGs in earthworm guts. CTL could increase the abundance of multidrug efflux pump genes and enhance the abundance of mobile genetic elements, especially plasmids. Various co-occurrence patterns between plasmids and ARGs were also found after CTL treatments. It is concluded that CTL may act as a selective stress for ARGs and lead to an increase in their abundance by facilitating the proliferation of potential ARG hosts and enhancing plasmid-mediated horizontal transfer frequency of ARGs in earthworm guts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The high abundance of antibiotic resistance genes (ARGs) in the fungicide residual environment, posing a threat to the environment and human health, raises the question of whether and how fungicide promotes the prevalence and dissemination of antibiotic resistance. Here, we reported a novel mechanism underlying bidirectional regulation of a typical heavy-metal-containing fungicide mancozeb on the horizontal transfer of ARGs. Our findings revealed that mancozeb exposure significantly exerted oxidative and osmotic stress on the microbes and facilitated plasmid-mediated ARGs transfer, but its metallic portions (Mn and Zn) were potentially utilized as essential ions by microbes for metalating enzymes to deal with cellular stress and thus reduce the transfer. The results of transcriptome analysis with RT-qPCR confirmed that the expression levels of cellular stress responses and conjugation related genes were drastically altered. It can be concluded mancozeb bidirectionally regulated the ARGs dissemination which may be attributed to the diverse effects on the microbes by its different portions. This novel mechanism provides an updated understanding of neglected fungicide-triggered ARGs dissemination and crucial insight for comprehensive risk assessment of fungicides., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

A novel antibacterial strategy is urgently required to develop for solving bacterial biofilm obstruction and bacterial drug resistance in the infected wound healing process. Herein, the Chitosan/Bletilla striata polysaccharide composited microneedles were prepared by chitosan, tannic acid, AgNO 3 and Bletilla striata polysaccharide through step centrifugation. In our design system, the porous structure of microneedles gradually disappeared, and the mechanical properties were significantly improved after multiple fillings. Ag + is reduced in-situ to silver nanoparticles by the abundant polyphenols of tannic acid, displaying antibacterial effects both in vitro and vivo, even for methicillin resistant Staphylococcus aureus. The addition of Bletilla striata polysaccharide increased the ability of piercing biofilm and promoted wound healing. The microneedles exhibited good biocompatibility and with function of piercing the bacterial biofilms, scavenging excessive free radicals, inhibiting inflammatory factors, and promoting wound healing. Therefore, the multifunctional composited microneedles show great potential to promote infected and susceptible wound healing., (Copyright © 2022. Published by Elsevier B.V.)

Thiamethoxam (TMX) is commonly applied on leek plants by root irrigation. It might be taken up by leek plants and thus has lasting dietary risk. In this study, the uptake, translocation, and metabolism of TMX in leek plants were investigated. The results obtained from both the hydroponic and soil experiments indicated that TMX could be easily translocated upward and accumulated in leek shoots after being absorbed by roots. The total absorbed TMX amount (M total ) in leek plants from the tested soils varied greatly with its adsorption governed by soil characteristics. Interestingly, M total was closely correlated with the concentration of TMX in in situ pore water, indicating that TMX in in situ pore water could be a useful approach to predict uptake of this chemical by leek plants from various soils. Profoundly, clothianidin (CLO) was detected with concentration of 0.07-1.54 mg/kg in roots and 0.27-4.12 mg/kg in shoots at 14 d, respectively, suggesting that TMX is easily converted into CLO in leek plants. The results showed that TMX used in soil is easily absorbed by leek and accumulated in edible parts accompanying with formation of CLO., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Wound dressing is a kind of significant artificial materials for protecting injured tissues and promoting wound healing. However, fabrication of antibacterial wound dressing usually involves tedious procedures and toxic components. Herein, we demonstrate a multifunctional chitosan/silver/tannic acid (CS/Ag/TA) cryogel based on an economic method to block acute hemorrhage and promote wound healing. The prepared CS/Ag/TA cryogel not only performs steady stability and compressibility, but also shows good antibacterial ability for both S. aureus and E. coli. Attributing to TA molecules, the CS/Ag/TA cryogel can effectively scavenge more than 95% of free radicals, showing effective oxidation resistance. Due to the porous structure and positive charge of CS, the prepared cryogel exhibits good hemostatic capability with a hemostasis time less than 20 s. Benefitting from the good biocompatibility and cell proliferation, the CS/Ag/TA cryogel can significantly promote wound repair in the skin incision model. All the results indicated that the greenly fabricated cryogel can be widely applied in clinic for hemostasis and wound healing., (Copyright © 2022. Published by Elsevier B.V.)

Elaborating the environmental behavior of mefentrifluconazole, a novel triazole fungicide, in stereoselective level is of paramount importance for the application of the pesticide in agriculture. In this study, the enantioselective bioactivity, acute toxicity and stereoselective bioaccumulation of mefentrifluconazole in earthworm (Eisenia fetida) were investigated. Bioactivity tests against four pathogens revealed that R-(-)-mefentrifluconazole exhibited approximately 11-113 times higher bioactivity than its S-(+)-mefentrifluconazole. However, the LC 50 of S-(+)-, rac- and R-(-)-mefentrifluconazole to earthworm was measured to be 4.1, 11.4 and 7.3 μg/cm 2 , respectively, indicating active ingredient R-(-)-mefentrifluconazole is less toxic than its racemate and S-form. Accumulation of mefentrifluconazole in earthworms was non-enantioselective and negatively related to its adsorption onto soils. The concentration of mefentrifluconazole in in situ pore water (C IPW ) and CaCl 2 extraction (C CaCl2 ) was closely related to its accumulation in earthworms, suggesting that C IPW and C CaCl2 could be appropriate indicators for estimation of the bioavailability of mefentrifluconazole in soil. Conclusively, our study provides necessary information for the risk assessment of mefentrifluconazole in agriculture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The extensive use of copper-based fungicides in orchards, especially in vineyards, leads to the accumulation of copper, which has caused growing concern. However, data on the acquisition of antibiotic resistance in opportunistic pathogens under copper-based fungicides are scarce. In this study, we investigated the potential development of antibiotic resistance in Escherichia coli K12 under selective copper hydroxide pressure. The results indicated that copper hydroxide at concentrations of 100 mg/L and 200 mg/L evolved resistance against chloramphenicol and tolerance against tetracycline to 4-8 and 2.00-2.67 times than the initial minimal inhibitory concentrations (MICs), respectively. Whole-genome sequencing analysis showed that the obtained resistant strains carried gene mutations including AcrAB-TolC multidrug efflux pump (acrB and marR), outer membrane porin (evZ), and another indirect pathways. Furthermore, the expression of multidrug efflux pump genes and oxidative stress-related genes were significantly upregulated, whereas outer membrane porin genes were downregulated. Thus, our results could well explain the emergence of antibiotic resistance and resistance mechanisms selected by copper-based fungicide, and provide a basis for the management of copper-based fungicide in agriculture to avoid the spread of antibiotic resistance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The healing of defected skin tissue is a complex process, especially for chronic wounds. Poor healing of these wounds may cause extensive suffering and high cost for patients. Traditional wound dressings are typically designed for a single function and they cannot satisfy all requirements for the whole process of wound healing. Therefore, it is necessary to develop new types of wound dressings with multiple functions for wound healing. In particular, adding an antibacterial function has been shown to be of great benefit during tissue repair. Nano‑silver is widely used in wound treatment because of various advantages, such as its wide antibacterial spectrum and lower drug resistance. Therefore, wound dressings loaded with nano‑silver have attracted widespread attention in wound healing. Naturally derived polysaccharides hold great potential as wound dressings, because of their abundant availability, low prices and good biocompatibility. In this review, nano‑silver functionalized polysaccharide-based wound dressings are systematically reviewed, including their preparation methods, antibacterial performances and classification of nano‑silver wound dressings. Moreover, the toxicity of nano‑silver based wound dressings is discussed and the prospective research direction is elaborated. This review aims to provide readers with an overview of the latest developments in silver nanotechnology, and to provide a little guidance for the research of nano‑silver functionalized polysaccharide-based wound dressings., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Foaming is a common operational problem that occurs in activated sludge (AS) from many wastewater treatment plants (WWTPs), but the characteristic of antibiotic resistance genes (ARGs) and human pathogenic bacteria (HPB) in foams is generally lacking. Here, we used a metagenomic approach to characterize the profile of ARGs and HPB in foams and AS from full-scale WWTPs receiving pesticide wastewater. No significant difference in the microbial communities was noted between the AS and foam samples. The diversity and abundance of ARGs in the foams were similar to those in the pertinent AS samples. Procrustes analysis suggested that the bacterial community is the major driver of ARGs. Metagenomic assembly also indicated that most ARGs (e.g., multidrug, rifamycin, peptides, macrolide-lincosamide-streptogramin, tetracycline, fluoroquinolone, and beta-lactam resistance genes) were carried by chromosomes rather than mobile genetic elements. Moreover, the relative abundances of HPB, Pseudomonas putida and Mycobacterium smegmatis, were enriched in the foam samples. Nine HPB were identified as carriers of 21 ARG subtypes, of which Pseudomonas aeruginosa could carry 12 ARG subtypes. Overall, this study indicates the prevalence of ARGs, HPB, and ARG-carrying HPB in foams, which highlights the potential risk of foams in spreading ARGs and HPB into the surrounding environments., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Difenoconazole is a triazole fungicide that is widely used worldwide and has been frequently detected in agricultural soils, but its ecotoxicological effect on soil bacterial community remains unknown. Here, the degradation of difenoconazole and its effect on soil bacterial communities were investigated at three concentrations in five different agricultural soils. Difenoconazole degraded faster in non-sterilized soils than in sterilized soils, suggesting that biodegradation is a major contributor to the dissipation of difenoconazole in soils. Exposure to high concentrations of difenoconazole decreased the soil bacterial community diversity in most soils, and this influence was aggravated with the increasing concentration. The effect of difenoconazole on soil bacterial community diversity was also enhanced with the increasing content of organic matter and total nitrogen in soils. Moreover, difenoconazole exposure also reduced the soil bacterial community network complexity and exhibited a concentration-dependent characteristic. In addition, a core bacterial community (57 operational taxonomic units, OTUs) was identified, and some core OTUs were strongly linked to the degradation of difenoconazole in soils. It is concluded that high concentrations of difenoconazole may have a significant effect on the soil bacterial communities, and co-occurrence networks may improve the ecotoxicological risk assessment of fungicides on soil microbiome., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Uptake of residual pesticides in a soil by a certain crop plant may be governed by their physicochemical properties. Uptake and translocation of pesticides (imidacloprid, acetamiprid, tricyclazole, azoxystrobin, tebuconazole and difenoconazole) with the octanol/water partition coefficient (log K ow ) ranging from 0.57 to 4.36 were investigated in soil with maize as a model plant. The results show that all tested pesticides in soil were uptaken by maize with accumulation amount of 27.73, 17.75, 18.96, 12.56, 10.66 and 2.13 μg for imidacloprid, acetamiprid, tricyclazole, azoxystrobin, tebuconazole and difenoconazole at 14 d, respectively. The accumulation amount was negatively correlated with adsorption coefficients and positively correlated with pesticide concentration in in situ pore water (C IPW ). Root bioconcentration factor varied widely from 0.61 for imidacloprid to 974.64 for difenoconazole was positively correlated with log K ow and molecular weight but negatively with water solubility. Conversely, translocation factor varied from 0 for difenoconazole to 1.64 for imidacloprid was negatively correlated with log K ow but positively with water solubility. It determined that uptake, accumulation and translocation of the pesticides in soil by maize are governed by their physicochemical properties, especially log K ow . C IPW is an appropriate candidate to evaluate the accumulation of pesticides in maize from soil., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The persistence and ecotoxicity of carbendazim residues pose a potential risk to environmental ecology and human health. Here, a novel and highly efficient carbendazim-degrading bacterium Rhodococcus sp. CX-1, capable of utilizing carbendazim as its sole source of carbon and energy, was isolated from contaminated soil. The biodegradation characteristics and metabolic pathways were studied by mass spectrometry, genomic annotation, and transcriptome analysis. The degradation rate of carbendazim by strain CX-1 was 3.98-9.90 mg/L/h under different conditions, and the optimum degradation conditions were 40 °C and pH 7.0. The addition of carbon sources (glucose, fructose, and sucrose, 100 mg/L) could accelerate carbendazim degradation. HPLC-MS/MS identification suggested that carbendazim is first hydrolyzed into 2-aminobenzimidazole and then to 2-hydroxybenzimidazole, and is ultimately mineralized to carbon dioxide. The genome of strain CX-1 contained 6,511,628 bp nucleotides, 2 linear plasmids, 2 circular plasmids, and 6437 protein coding genes. Genome annotation and transcriptome analysis indicated that carbendazim degradation may be regulated by the degradation genes harbored in the chromosome and in plasmid 2, and two different degradation pathways of carbendazim by imidazole ring cleavage or benzene ring cleavage were predicted. This study provided new insight to reveal the biodegradation mechanism of carbendazim; furthermore, strain CX-1 is a promising bioresource for carbendazim bioremediation., Competing Interests: Declaration of competing interest We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Storm runoff is important for maintaining surface water resources, while this function is significantly affected by land use and land cover changes, e.g., afforestation and reforestation. The Chinese Loess Plateau (CLP) has undergone large-scale vegetation rehabilitation, especially afforestation over the past 20 years. We hypothesize that afforestation has profoundly changed the amounts and mechanisms of storm runoff generation in headwater catchments on the CLP. To test this hypothesis, rainfall, soil moisture, and streamflow were monitored in a grass catchment and an adjacent forest catchment for two consecutive years. The objective of this study was to elucidate the varied mechanisms of storm runoff generation in these two contrasting revegetated catchments. Results showed that (1) average runoff coefficient in the grassland catchment (0.042) was approximately ten times higher than that in the forestland catchment (0.004), confirming the impact of catchment afforestation on the suppression of storm runoff generation. (2) Peak rainfall intensity was the first-order control of the runoff coefficient in the grassland catchment, but not in the forestland catchment. (3) Threshold values for antecedent soil moisture (~18%) and the sum of antecedent soil moisture index and event precipitation (~210 mm) were identified in the grassland catchment, above which storm runoff significantly increased. (4) Two extraordinary high runoff coefficient events were observed in the grassland catchment, one due to high peak rainfall intensity and strong surface runoff and the other due to high rainfall amount and high antecedent soil moisture. We conclude that long-term afforestation has changed the mechanisms and patterns of storm runoff generation, and different conditions of rainfall intensity, rainfall amount and antecedent soil moisture determined the hydrological connectivity between the upper hillslope and downhill gully in the catchment. This study deepens our understanding of the mechanisms and thresholds of storm runoff generation in headwater catchments on the CLP., Competing Interests: Declaration of competing interest The authors stated that this paper has no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Triazole-resistance in Aspergillus fumigatus is widespread. We evaluated whether triazole-resistance in A. fumigatus and its related cyp51A mutations, induced by a combination of the triazole fungicides difenoconazole and propiconazole, differs from resistance induced by the individual fungicides. Both difenoconazole and propiconazole can induce triazole-resistance in A. fumigatus. Resistance is much easier induced by formulated fungicides or a combination of these two fungicides compared with standard fungicides or individual fungicides, respectively. Six different mutations (G138S, G138D, H147Y, I246M, M263I and D430N) were identified in the induced resistant strains. The H147Y, I246M and M263I mutations were associated with triazole-resistance. This implies that the application of a combination of difenoconazole and propiconazole may result in higher triazole-resistance in A. fumigatus and more mutations in the cyp51A gene., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Organic manure has been implicated as an important source of antibiotic resistance genes (ARGs) in agricultural soils. However, the profiles of biocide resistance genes (BRGs), metal resistance genes (MRGs) and virulence genes (VGs) and their bacterial hosts in manure-amended soils remain largely unknown. Herein, a systematic metagenome-based survey was conducted to comprehensively explore the changes in resistomes, VGs and their bacterial hosts, mobile genetic elements (MGEs), and pathogenic bacteria in manure-amended greenhouse soils. Many manure-borne ARGs, BRGs, MRGs, VGs, and bacterial pathogens could be transferred into soils by applying manures, and their abundance and diversity were markedly positively correlated with greenhouse planting years (manure amendment years). The main ARGs transferred from manures to soils conferred resistance to tetracycline, aminoglycoside, and macrolide-lincosamide-streptogramin. Both statistical analysis and gene arrangements showed a good positive co-occurrence pattern of ARGs/BRGs/MRGs/VGs and MGEs. Furthermore, bacterial hosts of resistomes and VGs were significantly changed in the greenhouse soils in comparison with the field soils. Our findings confirmed the migration and dissemination of resistomes, VGs, and bacterial pathogens, and their accumulation and persistence were correlated with the continuous application of manures., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Antibiotic resistance genes (ARGs) harbored by plant microbiomes have been implicated as a potential risk to public health via food chain, especially directly edible fruits and vegetables. Here, we investigated the microbiome and antibiotic resistome in soil-strawberry ecosystem using shotgun metagenomic sequencing. The results showed that the enterobacterial population dominated the endophytes of strawberry fruits. Moreover, 85 subtypes of ARGs, including several clinically important ARGs, were detected in the strawberry fruit metagenomes. Additionally, host tracking analysis in combination with antibiotic-resistant bacterial isolate screening suggested that fruit-borne ARGs were mainly carried by members of the Enterobacteriaceae family. Unexpectedly, most of fruit-borne isolates were found to be resistant to several clinically important antimicrobials, e.g., erythromycin and cephalexin. Our findings provide broad insights into endophytic antibiotic resistomes of direct edible strawberry fruits and their potential hosts, and highlight the potential exposure risks of plant microbiomes to the human food chain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Residual acetochlor and atrazine in soils, resulting from their extensive application to maize plants, may affect product safety of the ultimate wheat crop. To determine the potential uptake and accumulation of acetochlor and atrazine by wheat plants, the uptake mechanism, translocation, and subcellular distribution of these two herbicides were studied through hydroponic experiments (10 mg L - 1 ). The results indicated that acetochlor can be taken up through the apoplastic pathway and can accumulate in wheat roots with little upward translocation. However, atrazine could be taken up by roots through the symplastic pathway and subsequently transported to the stems and leaves. Little upward translocation of acetochlor in wheat plants was due to its preferential distribution into root organelles with higher lipid contents. Conversely, the low bioconcentration of atrazine in root organelles and cell walls after uptake led to its easy upward translocation. Uptake of acetochlor and atrazine by wheat roots and the distribution of atrazine to the stems and leaves were predicted well by using the partition-limited model. The obtained results indicated that residual atrazine in soil may be taken up by wheat roots and acropetally translocated, thereby posing a threat to product safety of wheat., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aspergillus fumigatus is the mainly leading cause of invasive aspergillosis associated with significant morbidity and mortality in immunocompromised patients. However, triazole resistance in A. fumigatus has increased dramatically throughout the world nowadays. The emergence of triazole resistance has aroused growing concern. This research was conducted to assess if the resistance in A. fumigatus and its associated mutations in the cpy51A gene could be induced during its exposure to tebuconazole in liquid medium and in soil. The results indicated that the resistance in A. fumigatus with mutations of TR46/Y121F/T289A could be induced by tebuconazole in liquid medium. Nine resistant strains without any mutation in cyp51A were isolated in soil treated with tebuconazole at levels of 0.5-5.0 mg kg -1 after incubation for 120 d. The two (HI-30 and HI-36) of the nine resistant isolates were caused by overexpression of AtrF, AfuMDR1, cyp51A and cyp51B and hereditary stability. This strongly implies that conventional application of tebuconazole for plant protection will cause resistance of A. fumigatus to triazole medicals in agricultural soils., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The dissemination of antibiotic resistance genes (ARGs), human pathogenic bacteria (HPB), and antibiotic-resistant HPB (ARHPB) from animal feedlot to nearby environment poses a potentially high risk to environmental ecology and public health. Here, a metagenomic analysis was employed to explore the dissemination of ARGs, HPB, and ARHPB from a pig feedlot to surrounding stream and agricultural soils. In total, not detectable (ND)-1,628.4 μg/kg of antibiotic residues, 18 types of ARGs, 48 HPB species, and 216 ARB isolates were detected in all samples. Antibiotic residues from pig feedlot mainly migrated into stream sediments and greenhouse soil. The dominant ARGs and HPB species from pig feedlot spread into stream sediments (tetracycline resistance genes, Clostridium difficile, and Mycobacterium tuberculosis), stream water (multidrug resistance (MDR) genes, Shigella flexneri, and Bordetella pertussis), and greenhouse soil (MDR genes, Bacillus anthracis, and Brucella melitensis). It is concerning that 54.4% of 216 ARB isolates from all samples were potential ARHPB species, and genome sequencing and functional annotation of 4 MDR HPB isolates showed 9 ARG types. Our findings revealed the potential migration and dissemination of antibiotic residues, ARGs, HPB, and ARHPB from pig feedlot to surrounding stream and agricultural soils via pig sewage discharge and manure fertilization., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The biodegradability and ecological safety assessment of the previously isolated DDT-degrading bacterial strain Stenotrophomonas sp. DDT-1 were investigated in the DDT-contaminated soil under laboratory and field conditions. Under laboratory conditions, the degradation rates of fresh p,p'-DDT in soil were enhanced by 2.0-3.0-fold with the introduction of the strain DDT-1 compared to those of the control treatments. A similar enhancement in the dissipation of DDTs (p,p'-DDT, p,p'-DDE, p,p'-DDD, and o,p'-DDT) in the aged DDT-contaminated field plot soils resulted from the inoculation with this strain. Meanwhile, the degradation rates of DDTs increased by 2.9-5.5- and 2.8-7.6-fold in the inoculated greenhouse and open field soils, respectively, after field demonstration application of strain DDT-1 preparation. Moreover, no significant differences in the soil enzyme activity, microbial functional diversity, and bacterial community structure were observed between the inoculated and un-inoculated field soils, but several soil microbial genera exhibited some fluctuations in abundance. It is concluded that strain DDT-1 could accelerate the removal of DDTs residues in field soils, and furthermore, its inoculation was ecologically safe., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The dissipation of ciprofloxacin (CIP, 1.0 and 10.0mg/kg) and kresoxim-methyl (KM, 1.0 and 2.0mg/kg) in manure-amended soil, the variations in soil enzyme activities and microbial functional diversities, and CIP-induced bacterial community tolerances were studied using a chromatographic analysis, enzyme colorimetric and titration analyses, and the BIOLOG EcoPlate method. Three successive treatments of individual and combined samples of CIP and KM at low and high concentrations were performed at 60d intervals. The dissipation half-life of CIP increased, but that of KM decreased in manured soil with treatment frequency; furthermore, the combined treatment altered the dissipation rates of CIP and KM. A stronger inhibitory effect on the activities of soil neutral phosphatase and urease was observed in the individual KM treatment than in the individual CIP treatment. A similar inhibitory trend was also found in soil neutral phosphatase activity in the combined treatment at high concentration compared to that at low concentration, but the activity of soil catalase was enhanced in the early stages of the KM or CIP treatments. Meanwhile, the inhibitory trend on the overall activity and functional diversity of soil microorganisms was observed in the individual KM or CIP treatment, and the combined treatment exerted a greater suppression effect than that in the individual treatment. Bacterial community resistance to CIP increased significantly with increasing treatment frequency and concentration, and furthermore antibiotic resistance developed faster in the combined treatment than in the individual treatment. It was concluded that the repeated treatments of CIP and KM could alter their dissipation rates and soil enzyme activities, suppress microbial functional diversity, and increase bacterial community resistance to CIP in manured soil., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The application of the herbicide chlorimuron-ethyl has a lasting toxic effect on some succession crops. Here, a bacterium capable of utilizing chlorimuron-ethyl as the sole source of nitrogen was isolated from the contaminated soil and was identified as Enterobacter ludwigii sp. CE-1, and its detoxification and degradation of the herbicide were then examined. The biodegradation of chlorimuron-ethyl by the isolate CE-1 was significantly accelerated with increasing concentration (1-10mg/l) and temperature (20-40°C). The optimal pH for the degradation of chlorimuron-ethyl by the isolate CE-1 was pH 7.0. A pathway for the biodegradation of chlorimuron-ethyl by the isolate CE-1 was proposed, in which it could be first converted into 2-amino-4-chloro-6-methoxypyrimidine and an intermediate product by the cleavage of the sulfonylurea bridge and then transformed into saccharin via hydrolysis and amidation. The plant height and fresh weight of corn that had been incubated in nutrient solution containing 0.2mg/l of chlorimuron-ethyl significantly recovered to 83.9% and 83.1% compared with those in the uninoculated control, although the root growth inhibition of chlorimuron-ethyl could not be alleviated after inoculation for 14 d. The results indicate that the isolate CE-1 is a promising bacterial resource for the biodegradation and detoxification of chlorimuron-ethyl., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Fomesafen is a long residual herbicide and poses a potential risk to environmental safety, leading to an increasing need to find eco-friendly and cost-effective techniques to remediate fomesafen-contaminated soils. In this article, a novel strain of Bacillus sp., FE-1 was isolated from paddy field soil. This strain was found to degrade fomesafen both in liquid medium and in soil. >82.9% of fomesafen, at concentrations of 0.5, 1 and 10mgL -1 , was degraded by Bacillus sp. FE-1 in liquid medium within 14h. The optimal pH and temperature for degradation were 7.0 and 35°C, respectively. Soil samples inoculated with strain FE-1 showed significantly increased rates of fomesafen degradation. Two metabolites of fomesafen degradation were detected and identified as amino-fomesafen and 5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-amino-benzoic acid. This is the first report of a novel fomesafen biodegradation pathway involving the reduction of a nitro group followed by the hydrolysis of an amide bond. The excellent remediation capability of the isolate FE-1 to detoxify fomesafen-contaminated soil was shown by bioassay of the sensitive aftercrop corn. The results indicate that Bacillus sp. FE-1 has potential for use in the bioremediation of fomesafen-contaminated soil., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A strain of Ochrobactrum sp. DDT-2 that was capable of degrading DDT as the sole carbon and energy source was isolated and sequenced, and its biodegradation characteristics and metabolism mechanism were examined. The genome sequence of the isolate DDT-2 was composed of 4,630,303bp with a GC content of 55.99% and 4454 coding genes. The degradation rate of DDT by the isolate DDT-2 increased with the increasing substrate concentration (0.1-10mg/l) and temperature (20-40°C). The degradation half-life of DDT in the presence of the isolate DDT-2 at pH7.0 was obviously shorter than those at pH5.0 and 9.0. Potential DDT degradation genes were found in the isolate DDT-2 genome by a BLASTx search against a DDT degradation genes (DDGs) database. A common biodegradation pathway of DDT was proposed based on the combined analysis of genome annotation and mass spectrometry. DDT was initially dechlorinated to form DDD and DDE. Then, it was transformed into DDMU and DDA via dechlorination and carboxylation, and it may ultimately be mineralized to carbon dioxide. The results suggested that the isolate DDT-2 could be useful for the bioremediation of DDT and its metabolite residues., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Azole resistance in Aspergillus fumigatus is a growing public health problem. The sources of this resistance have been gained much attention. The present study was conducted to assess if resistant strain of A. fumigatus and its associated mutations in cyp51A could be induced by triazole fungicides and whether the resistant strain of A. fumigatus exist in agricultural fields. The results indicated that the resistance in A. fumigatus with mutations of TR46/Y121F/T289A, A284T, G448S and P222Q could be induced by agricultural triazoles (epoxiconazole, tebuconazole, propiconazole, hexaconazole, and metconazole). TR46/Y121F/T289A was the most common mutation in the induced resistant strain of A. fumigatus. A total of 144 soil samples were collected from different greenhouses for vegetables and fruits in Zhejiang, China. Among them, 2 voriconazole-resistant strains (No. 15 and 44) harboring the mutation of TR46/Y121F/T289A and 1 itraconazole-resistant strain (No. 51) harboring the mutation of TR34/L98H/S297T/F495I were isolated and identified. This implies that resistant strain of A. fumigatus has already distributed at least in 5.8% of the greenhouses. These findings might imply that there is a direct link between the agricultural use of triazoles and the appearance of the resistance in A. fumigatus to triazole medicals and its associated mutations in cyp51A., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The degradation characteristics of carbendazim (CBD) and chlortetracycline (CTC) in individual and combined treatments, and dynamics of soil microbial structural and functional diversity as well as their potential relations were studied during three repeated treatments using different concentrations. The results showed that the degradation half-life of CBD at concentrations of 3mg/kg and 6mg/kg obviously increased, but that of CTC at levels of 1mg/kg and 10mg/kg decreased with increasing treatment frequency. Soil microbial activity and functional diversity displayed the suppression trend in CBD treatment and the suppression-recovery-stimulation trend in CTC and CBD+CTC treatments, which were consistent with the findings of decreased degradation rate of CBD and increased degradation rate of CTC. 16S amplicon sequencing analysis revealed five potentially dominant CTC-resistant microbial genera including Bacillus, Actinobacillus, Pseudomonas, Mycobacterium, and Corynebacterium, which may mainly carry major facilitator superfamily transporter protein, ribosomal protection protein, and other proteins encoded by tetA, tetB, tetC, tetH, tetL, tetM, tetO, tetV, tetW, tetX, tetZ, tet33, and tet39. These five dominant genera may jointly contribute to the elevated bacterial community resistance to CTC. Our findings provided a better understanding of microbial community structure and function changes in repeatedly treated soils with CBD and CTC., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Nitric oxide (NO) and mitogen-activated protein kinase (MPK) play important roles in brassinosteroid (BR)-induced stress tolerance, however, their functions in BR-induced pesticides metabolism remain unclear. Here, we showed that MPK activity and transcripts of SlMPK1 and SlMPK2 were induced by chlorothalonil (CHT), a widely used fungicide, in tomato leaves. However, cosilencing of SlMPK1/2 compromised the 24-epibrassinolide (EBR)-induced upregulation of detoxification genes and CHT metabolism in tomato leaves. In addition, cosilencing of SlMPK1/2 inhibited the accumulation of S-nitrosothiol (SNO), the reservoir of nitric oxide (NO) in plants, whereas tungstate, the inhibitor of nitrate reductase (NR), blocked EBR-induced SNO accumulation and MPK activity. Inhibiting the accumulation of NO by cPTIO, the specific scavenger and tungstate abolished the EBR-induced upregulation of detoxification genes, glutathione accumulation and CHT metabolism. The results showed that MPK and NR-dependent NO were involved in BR-induced CHT metabolism. Notably, there was a positive crosstalk between the MPK and NO production., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Substantial application of the herbicide atrazine in agriculture leads to persistent contamination, which may damage the succeeding crops and pose potential threats to soil ecology and environmental health. Here, the degradation characteristics of atrazine and dynamic change of soil bacterial community structure and function as well as their relations were studied during three repeated treatments at the recommended, double, and five-fold doses. The results showed that the degradation half-life of atrazine obviously decreased with increased treatment frequency. Soil microbial functional diversity displayed a variation trend of suppression-recovery-stimulation, which was associated with increased degradation rate of atrazine. 16S amplicon sequencing was conducted to explore bacterial community structure and correlate the genus to potential atrazine degradation. A total of seven potentially atrazine-degrading bacterial genera were found including Nocardioides, Arthrobacter, Bradyrhizobium, Burkholderia, Methylobacterium, Mycobacterium, and Clostridium. These bacterial genera showed almost complete atrazine degradation pathways including dechlorination, dealkylation, hydroxylation, and ring cleavage. Furthermore, the relative abundance of four of them (i.e., Nocardioides, Arthrobacter, Methylobacterium, and Bradyrhizobium) increased with treatment frequency and atrazine concentration, suggesting that they may participate in atrazine degradation during repeated treatments. Our findings reveal the potential relationship between atrazine degradation and soil bacterial community structure in repeatedly treated soils., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The abundance and diversity of biodegradation genes (BDGs) and potential degradation pathways of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and atrazine (ATZ) in freshwater and marine sediments were investigated by metagenomic analysis using 6 datasets (16Gb in total). The datasets were derived using Illumina high-throughput sequencing and were based on BLAST against self-established databases of BDGs, DDT degradation genes (DDGs), HCH degradation genes (HDGs), and ATZ degradation genes (ADGs). The results showed that the abundance and diversity of BDGs, DDGs, HDGs, and ADGs varied with sample source and locations. The lip and mnp genes, which encode for peroxidase, and the carA gene, which encodes for laccase, were detected as the dominant genes for degradation of organic pollutants. The hdt, hdg, and atzB genes, which encode for hydratase, dehalogenase, and ethylaminohydrolase, were found to be the most abundant genes involved in DDT, HCH, and ATZ degradation, respectively. The identified 69 genera capable of degrading organic pollutants were mostly affiliated with Proteobacteria (49.3%) and Actinobacteria (21.7%). Four genera, including Plesiocystis, Anaerolinea, Jannaschia, and Mycobacterium, were the major biodegradation populations in all sediments. In this study, the nearly complete biodegradation pathways of DDT and ATZ were found, and the partial degradation pathway of HCH was detected in all sediments., (© 2013.)

Both sorption by soil and uptake by organisms of ionizable organic pollutants depend on their speciation (i.e., neutral and ionized forms); thus, the bioavailability of ionizable organic pollutants is more complicated than that of neutral organic pollutants in soil. The toxicity of the weak base carbendazim to earthworms (Eisenia fetida) was estimated using Soxhlet extracted concentrations (C(SE)), an excess of water extracted concentrations (C(EEW)), ex situ pore water concentrations (C(EPW)) and in situ pore water concentrations (C(IPW)) in different soils. The results indicated that the median lethal concentrations (LC50) calculated from C(SE) ranged from 2.32 to 34.0 mg kg(-1) in the five tested soils and the coefficient of variation (CV) of LC50s was 69.8%. When the LC50 was calculated from the C(EEW), C(EPW) and C(IPW), the variability of the LC50 gradually became smaller in these soils, with the CVs of LC50s being 58.1%, 50.6% and 38.6% (for C(EEW), C(EPW) and C(IPW), respectively). However, the LC50 based on C(IPW) in strongly acidic soil (where carbendazim partially exists as ionized form) was significantly lower than in other soils, and the values of the LC50 calculated from the in situ pore water concentrations were approximately equal. The results indicated that the in situ pore water concentration could be used to estimate the toxicity of carbendazim in different soils especially in those soils where carbendazim exists in the neutral form., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The effect of successive chlorothalonil applications on the persistence of chlorothalonil, soil respiration activity, and dehydrogenase activity (DHA) in soil was investigated under laboratory conditions. The persistence of chlorothalonil in soil was prolonged significantly with the increase in the concentration applied. Repeated applications of chlorothalonil at 25 mg kg⁻¹ led to its accumulation in soil. The effect of repeated chlorothalonil applications on soil respiration and DHA was found to be a concentration-dependent process. Soil respiration was permanently inhibited by the successive introductions of chlorothalonil at 25 mg kg⁻¹. DHA was reduced significantly on day 15 after four successive treatments of 10 mg kg⁻¹ and 25 mg kg⁻¹ of chlorothalonil, although a recovery trend could be found after the third and fourth treatments. Repeated chlorothalonil applications might increase the persistence of chlorothalonil in soil and thus alter soil microbial activity., (Copyright © 2012 Elsevier Inc. All rights reserved.)

To overcome the poor survival and low activity of the bacteria used for bioremediation, a plasmid-mediated bioaugmentation method was investigated, which could result in a persistent capacity for the degradation of chlorpyrifos in soil. The results indicate that the pDOC plasmid could transfer into soil bacteria, including members of the Pseudomonas and Staphylococcus genera. The soil bacteria acquired the ability to degrade chlorpyrifos within 5 days of the transfer of pDOC. The efficiency of the pDOC transfer in the soil, as measured by the chlorpyrifos degradation efficiency and the most probable number (MPN) of chlorpyrifos degraders, was influenced by the soil temperature, moisture level and type. The best performance for the transfer of pDOC was observed under conditions of 30°C and 60% water-holding capacity (WHC). The results presented in this paper show that the transfer of pDOC can enhance the degradation of chlorpyrifos in various soils, although the degradation efficiency did vary with the soil type. It may be concluded that the introduction of plasmids encoding enzymes that can degrade xenobiotics or donor strains harboring these plasmids is an alternative approach in bioaugmentation., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The effect of repeated carbendazim applications on functional diversity of culturable microorganisms and bacterial community composition was studied under field conditions. The functional diversity of soil culturable microbial community (Shannon index, H') reduced significantly (P<0.05) after the first introduction of carbendazim at levels of 0.94, 1.88 and 4.70 kg active ingredient (a.i.)ha(-1) and then recovered to that in the control with subsequent applications. An evident (P<0.01) difference in the bacterial community composition was observed after the second carbendazim application by Temperature Gradient Gel Electrophoresis (TGGE) analysis of 16S rRNA genes amplified from treated and control soils, which remained after the third and fourth treatments. Our results indicated that repeated carbendazim applications have a transient harmful effect on functional diversity of soil culturable microbial community and result in an alteration in bacterial community composition largely due to one species within the γ-proteobacterium., (Copyright © 2011 Elsevier Inc. All rights reserved.)

A bacterial strain DDT-6 (D6) capable of utilizing dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE) (DDTs) as its sole carbon and energy source was isolated and identified as Sphingobacterium sp. The degradation of DDTs by strain D6 in mineral salt medium and in field soil was investigated. The half-lives of the degradation of DDTs increased with increasing concentration ranging from 1 to 50 mg L(-1). Favorable degradation conditions for DDTs by strain D6 were found to be pH 7.0 and 30°C. The degradation of DDTs by strain D6 was found to be statistically significantly enhanced (p ≤ 0.05) by the addition of glucose. Based on the metabolites detected, a pathway was proposed for DDT degradation in which it undergoes dechlorination, hydrogenation, dioxygenation, decarboxylation, hydroxylation, and phenyl ring-cleavage reactions to complete the mineralization process. The addition of strain D6 into the contaminated soils was found to statistically significantly enhance (p ≤ 0.05) the degradation of DDTs. The results indicate that the isolate D6 can be used successfully for the removal or detoxification of residues of DDTs in contaminated soil., (Copyright © 2010 Elsevier B.V. All rights reserved.)

In this paper, the spectroscopic properties of Nd(3+) doped transparent oxyfluoride glass ceramics containing LaF(3) nano-crystals were systematically studied. The formation and distribution of LaF(3) nano-crystals in the glass matrix were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Based on Judd-Ofelt theory, the intensity parameters Omega(t) (t=2, 4, 6), spontaneous emission probability, radiative lifetime, radiative quantum efficiency, width of the emission line and stimulated emission cross-section of Nd(3+) were evaluated. Particularly, the effect of Nd(3+) doping level on them was discussed. With the increase of Nd(3+) concentration in the glass ceramic, the experimental luminescence lifetime, radiative quantum efficiency and stimulated emission cross-section vary from 353.4 micros, 78.3% and 1.86 x 10(-20)cm(2) to 214.7 micros, 39.9% and 1.52 x 10(-20)cm(2), respectively. The comparative study of Nd(3+) spectroscopic parameters in different hosts suggests that the investigated glass ceramic system is potentially applicable as laser materials for 1.06 microm emission.