The Experts below are selected from a list of 2748 Experts worldwide ranked by ideXlab platform
Yi-jun Dai - One of the best experts on this subject based on the ideXlab platform.
-
Biodegradation of the Neonicotinoid Insecticide Acetamiprid by Actinomycetes Streptomyces canus CGMCC 13662 and Characterization of the Novel Nitrile Hydratase Involved
Journal of agricultural and food chemistry, 2019Co-Authors: Ling Guo, Wen-wan Fang, Leilei Guo, Chuan-fei Yao, Yun-xiu Zhao, Yi-jun DaiAbstract:Neonicotinoid Insecticide pollution in soil and water poses serious environmental risks. Microbial biodegradation is an important Neonicotinoid Insecticide degradation pathway in the environment. I...
-
Biodegradation of the Neonicotinoid Insecticide Acetamiprid by Actinomycetes Streptomyces canus CGMCC 13662 and Characterization of the Novel Nitrile Hydratase Involved
2019Co-Authors: Ling Guo, Wen-wan Fang, Leilei Guo, Chuan-fei Yao, Yun-xiu Zhao, Yi-jun DaiAbstract:Neonicotinoid Insecticide pollution in soil and water poses serious environmental risks. Microbial biodegradation is an important Neonicotinoid Insecticide degradation pathway in the environment. In this study, 70.0% of the acetamiprid in a 200 mg/L solution was degraded by actinomycetes Streptomyces canus CGMCC 13662 (isolated from soil) in 48 h, and the acetamiprid degradation half-life was 27.7 h. Acetamiprid was degraded to IM-1-2 ((E)-1-(1-(((6-chloropyridin-3-yl)methyl)(methyl) amino)ethylidene)urea) through hydrolysis of the cyanoimine moiety. Gene cloning and overexpression indicated that a novel nitrile hydratase with three unusual subunits (AnhD, AnhE, and AnhA) without accessory protein mediated IM-1-2 formation. The purified nitrile hydratase responsible for degrading acetamiprid had a Km of 5.85 mmol/L and a Vmax of 15.99 U/mg. A homology model suggested that AnhD-Glu56 and AnhE-His21 play important roles in the catalytic efficiency of the nitrile hydratase. S. canus CGMCC 13662 could be used to remediate environments contaminated with acetamiprid
-
biodegradation of the Neonicotinoid Insecticide acetamiprid in surface water by the bacterium variovorax boronicumulans cgmcc 4969 and its enzymatic mechanism
RSC Advances, 2017Co-Authors: Shi-lei Sun, Wenlong Yang, Jingjing Guo, Yining Zhou, Xue Rui, Chen Chen, Yi-jun DaiAbstract:The plant growth-promoting rhizobacterium Variovorax boronicumulans CGMCC 4969 was used to degrade the Neonicotinoid Insecticide, acetamiprid (AAP), in surface water, and the enzymatic mechanisms of AAP degradation in V. boronicumulans CGMCC 4969 were explored. V. boronicumulans CGMCC 4969 degraded 34.7% of 2 mg L−1 AAP over 120 h with a degradation half-life of 182 h in surface water, and the major metabolite was the amide product, (E)-N2-carbamoyl-N1-[(6-chloro-3-pridyl) methyl]-N1-methylacetamidine (IM-1-2). Gene cloning and over-expression studies proved that AAP hydration to IM-1-2 was mediated by a nitrile hydratase (ANHase). Addition of AAP to the mineral salt medium (MSM) broth significantly upregulated the ANHase gene expression by 1.6-fold, when compared with that in the control without AAP. Co-expression of the ANHase gene with its activator gene (anhC) apparently increased ANHase activity 21-fold for AAP hydration compared with the ANHase gene alone. The independent over-expression of anhC gave rise to competitive inhibition on the β-subunit of the ANHase and resulted in decreased ANHase activity. This ANHase is versatile, hydrating aromatic, N-heterocyclic, and aliphatic nitrile compounds. The present study shows the potential of V. boronicumulans CGMCC 4969 in the bioremediation of AAP contaminated water.
-
Degradation of the Neonicotinoid Insecticide Acetamiprid via the N-Carbamoylimine Derivate (IM-1-2) Mediated by the Nitrile Hydratase of the Nitrogen-Fixing Bacterium Ensifer meliloti CGMCC 7333
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Ling-yan Zhou, Long-jiang Zhang, Shi-lei Sun, Shi-yun Mao, Zhong-hua Liu, Yi-jun Dai, Sheng YuanAbstract:The metabolism of the widely used Neonicotinoid Insecticide acetamiprid (ACE) has been extensively studied in plants, animals, soils, and microbes. However, hydration of the N-cyanoimine group in ACE to the N-carbamoylimine derivate (IM-1-2) by purified microbes, the enzyme responsible for this biotransformation, and further degradation of IM-1-2 have not been studied. The present study used liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy to determine that the nitrogen-fixing bacterium Ensifer meliloti CGMCC 7333 transforms ACE to IM-1-2. CGMCC 7333 cells degraded 65.1% of ACE in 96 h, with a half-life of 2.6 days. Escherichia coli Rosetta (DE3) overexpressing the nitrile hydratase (NHase) from CGMCC 7333 and purified NHase converted ACE to IM-1-2 with degradation ratios of 97.1% in 100 min and 93.9% in 120 min, respectively. Interestingly, IM-1-2 was not further degraded by CGMCC 7333, whereas it was spontaneously hydrolyzed at the N-carbamoylimine group to the derivat...
-
the metabolism of Neonicotinoid Insecticide thiamethoxam by soil enrichment cultures and the bacterial diversity and plant growth promoting properties of the cultured isolates
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2014Co-Authors: Guangcan Zhou, Ling-yan Zhou, Yi-jun Dai, Ying Wang, Shan Zhai, Sheng YuanAbstract:A soil enrichment culture (SEC) rapidly degraded 96% of 200 mg L(-1) Neonicotinoid Insecticide thiamethoxam (TMX) in MSM broth within 30 d; therefore, its metabolic pathway of TMX, bacterial diversity and plant growth-promoting rhizobacteria (PGPR) activities of the cultured isolates were studied. The SEC transformed TMX via the nitro reduction pathway to form nitrso, urea metabolites and via cleavage of the oxadiazine cycle to form a new metabolite, hydroxyl CLO-tri. In addition, 16S rRNA gene-denaturing gradient gel electrophoresis analysis revealed that uncultured rhizobacteria are predominant in the SEC broth and that 77.8% of the identified bacteria belonged to uncultured bacteria. A total of 31 cultured bacterial strains including six genera (Achromobacter, Agromyces, Ensifer, Mesorhizobium, Microbacterium and Pseudoxanthomonas) were isolated from the SEC broth. The 12 strains of Ensifer adhaerens have the ability to degrade TMX. All six selected bacteria showed PGPR activities. E. adhaerens TMX-23 and Agromyces mediolanus TMX-25 produced indole-3-acetic acid, whereas E. adhaerens TMX-23 and Mesorhizobium alhagi TMX-36 are N2-fixing bacteria. The six-isolated microbes were tolerant to 200 mg L(-1) TMX, and the growth of E. adhaerens was significantly enhanced by TMX, whereas that of Achromobacter sp. TMX-5 and Microbacterium sp.TMX-6 were enhanced slightly. The present study will help to explain the fate of TMX in the environment and its microbial degradation mechanism, as well as to facilitate future investigations of the mechanism through which TMX enhances plant vigor.
Johanna Yourstone - One of the best experts on this subject based on the ideXlab platform.
-
seed coating with a Neonicotinoid Insecticide negatively affects wild bees
Nature, 2015Co-Authors: Maj Rundlof, Georg K.s. Andersson, Veronica Hederström, Lina Herbertsson, Björn K. Klatt, Thorsten R. Pedersen, Ove Jonsson, Ingemar Fries, Riccardo Bommarco, Johanna YourstoneAbstract:Neonicotinoid seed coating is associated with reduced density of wild bees, as well as reduced nesting of solitary bees and reduced colony growth and reproduction of bumblebees, but appears not to affect honeybees. Reports that Neonicotinoid Insecticides have adverse effects on bee populations remain controversial. Some studies have been criticized as using unrealistically high Insecticide dosages or conditions far removed from those in the field, and it has been suggested that bees might be able to detect the Insecticides and avoid treated crops. Two papers in this issue of Nature present results that fill some of the gaps in our knowledge. In laboratory experiments Sebastien Kessler et al. use field-level doses of three commonly used Neonicotinoids — clothianidin, imidacloprid and thiamethoxam — to show that both honeybees and bumblebees are able to detect their presence. However, the bees do not avoid Neonicotinoid-treated food and may even prefer it. Maj Rundlof et al. sowed oilseed rape with and without a clothianidin seed coating in matched and replicated agricultural landscapes. They found the seed coating to be associated with reduced density of wild bees, as well as reduced nesting of solitary bees and reduced colony growth of bumblebees, but they did not detect an effect on honeybees. Understanding the effects of Neonicotinoid Insecticides on bees is vital because of reported declines in bee diversity and distribution1,2,3 and the crucial role bees have as pollinators in ecosystems and agriculture4. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants5, and the European Union has therefore introduced a moratorium on three Neonicotinoids as seed coatings in flowering crops that attract bees6. The moratorium has been criticized for being based on weak evidence7, particularly because effects have mostly been measured on bees that have been artificially fed Neonicotinoids8,9,10,11. Thus, the key question is how Neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes11,12,13. Here we show that a commonly used Insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an Insecticide containing a combination of the Neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees1,2,3 may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees.
-
Seed coating with a Neonicotinoid Insecticide negatively affects wild bees
Nature, 2015Co-Authors: Maj Rundlof, Georg K.s. Andersson, Veronica Hederström, Lina Herbertsson, Björn K. Klatt, Thorsten R. Pedersen, Ove Jonsson, Ingemar Fries, Riccardo Bommarco, Johanna YourstoneAbstract:Understanding the effects of Neonicotinoid Insecticides on bees is vital because of reported declines in bee diversity and distri- bution1–3 and the crucial role bees have as pollinators in ecosystems and agriculture4 . Neonicotinoids are suspected to pose an unac- ceptable risk to bees, partly because of their systemic uptake in plants5 , and the European Union has therefore introduced a mora- torium on three Neonicotinoids as seed coatings in flowering crops that attract bees6 . The moratorium has been criticized for being based on weak evidence7 , particularly because effects have mostly been measured on bees that have been artificially fed neonicoti- noids8–11 . Thus, the key question is how Neonicotinoids influence bees, and wild bees in particular, in real-world agricultural land- scapes11–13 . Here we show that a commonly used Insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an Insecticide containing a combina- tion of the Neonicotinoid clothianidin and the non-systemic pyre- throid b-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees1–3 may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees
Sheng Yuan - One of the best experts on this subject based on the ideXlab platform.
-
Degradation of the Neonicotinoid Insecticide Acetamiprid via the N-Carbamoylimine Derivate (IM-1-2) Mediated by the Nitrile Hydratase of the Nitrogen-Fixing Bacterium Ensifer meliloti CGMCC 7333
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Ling-yan Zhou, Long-jiang Zhang, Shi-lei Sun, Shi-yun Mao, Zhong-hua Liu, Yi-jun Dai, Sheng YuanAbstract:The metabolism of the widely used Neonicotinoid Insecticide acetamiprid (ACE) has been extensively studied in plants, animals, soils, and microbes. However, hydration of the N-cyanoimine group in ACE to the N-carbamoylimine derivate (IM-1-2) by purified microbes, the enzyme responsible for this biotransformation, and further degradation of IM-1-2 have not been studied. The present study used liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy to determine that the nitrogen-fixing bacterium Ensifer meliloti CGMCC 7333 transforms ACE to IM-1-2. CGMCC 7333 cells degraded 65.1% of ACE in 96 h, with a half-life of 2.6 days. Escherichia coli Rosetta (DE3) overexpressing the nitrile hydratase (NHase) from CGMCC 7333 and purified NHase converted ACE to IM-1-2 with degradation ratios of 97.1% in 100 min and 93.9% in 120 min, respectively. Interestingly, IM-1-2 was not further degraded by CGMCC 7333, whereas it was spontaneously hydrolyzed at the N-carbamoylimine group to the derivat...
-
the metabolism of Neonicotinoid Insecticide thiamethoxam by soil enrichment cultures and the bacterial diversity and plant growth promoting properties of the cultured isolates
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2014Co-Authors: Guangcan Zhou, Ling-yan Zhou, Yi-jun Dai, Ying Wang, Shan Zhai, Sheng YuanAbstract:A soil enrichment culture (SEC) rapidly degraded 96% of 200 mg L(-1) Neonicotinoid Insecticide thiamethoxam (TMX) in MSM broth within 30 d; therefore, its metabolic pathway of TMX, bacterial diversity and plant growth-promoting rhizobacteria (PGPR) activities of the cultured isolates were studied. The SEC transformed TMX via the nitro reduction pathway to form nitrso, urea metabolites and via cleavage of the oxadiazine cycle to form a new metabolite, hydroxyl CLO-tri. In addition, 16S rRNA gene-denaturing gradient gel electrophoresis analysis revealed that uncultured rhizobacteria are predominant in the SEC broth and that 77.8% of the identified bacteria belonged to uncultured bacteria. A total of 31 cultured bacterial strains including six genera (Achromobacter, Agromyces, Ensifer, Mesorhizobium, Microbacterium and Pseudoxanthomonas) were isolated from the SEC broth. The 12 strains of Ensifer adhaerens have the ability to degrade TMX. All six selected bacteria showed PGPR activities. E. adhaerens TMX-23 and Agromyces mediolanus TMX-25 produced indole-3-acetic acid, whereas E. adhaerens TMX-23 and Mesorhizobium alhagi TMX-36 are N2-fixing bacteria. The six-isolated microbes were tolerant to 200 mg L(-1) TMX, and the growth of E. adhaerens was significantly enhanced by TMX, whereas that of Achromobacter sp. TMX-5 and Microbacterium sp.TMX-6 were enhanced slightly. The present study will help to explain the fate of TMX in the environment and its microbial degradation mechanism, as well as to facilitate future investigations of the mechanism through which TMX enhances plant vigor.
-
biodegradation of the Neonicotinoid Insecticide thiamethoxam by the nitrogen fixing and plant growth promoting rhizobacterium ensifer adhaerens strain tmx 23
Applied Microbiology and Biotechnology, 2013Co-Authors: Guangcan Zhou, Ying Wang, Shan Zhai, Feng Ge, Sheng YuanAbstract:Thiamethoxam (THIA), a second generation Neonicotinoid Insecticide in the thianicotinyl subclass, is used worldwide. Environmental studies revealed that microbial degradation is the major mode of removal of this pesticide from soil. However, microbial transformation of THIA is poorly understood. In the present study, we isolated a bacterium able to degrade THIA from rhizosphere soil. The bacterium was identified as Ensifer adhaerens by its morphology and 16S ribosomal DNA sequence analysis. High-performance liquid chromatography and mass spectrometry analysis suggested that the major metabolic pathway of THIA in E. adhaerens TMX-23 involves the transformation of its N-nitroimino group (=N–NO2) to N-nitrosoimino (=N–NO) and urea (=O) metabolites. E. adhaerens TMX-23 is a nitrogen-fixing bacterium harboring two types of nifH genes in its genome, one of which is 98 % identical to the nifH gene in the cyanobacterium Calothrix sp. MCC-3A. E. adhaerens TMX-23 released various plant-growth-promoting substances including indole-3-acetic acid, exopolysaccharides, ammonia, HCN, and siderophores. Inoculation of E. adhaerens TMX-23 onto soybean seeds (Glycine max L.) with NaCl at 50, 100, or 154 mmol/L increased the seed germination rate by 14, 21, and 30 %, respectively. THIA at 10 mg/L had beneficial effects on E. adhaerens TMX-23, enhancing growth of the bacterium and its production of salicylic acid, an important plant phytohormone associated with plant defense responses against abiotic stress. The nitrogen-fixing and plant-growth-promoting rhizobacterium E. adhaerens TMX-23, which is able to degrade THIA, has the potential for bioaugmentation as well as to promote growth of field crops in THIA-contaminated soil.
-
biotransformation of the Neonicotinoid Insecticide thiacloprid by the bacterium variovorax boronicumulans strain j1 and mediation of the major metabolic pathway by nitrile hydratase
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Huijuan Zhang, Qianwen Zhou, Guangcan Zhou, Guangdong Shang, Weiwei Ji, Sheng YuanAbstract:A Neonicotinoid Insecticide thiacloprid-degrading bacterium strain J1 was isolated from soil and identified as Variovorax boronicumulans by 16S rRNA gene sequence analysis. Liquid chromatography–mass spectrometry and nuclear magnetic resonance analysis indicated the major pathway of thiacloprid (THI) metabolism by V. boronicumulans J1 involved hydrolysis of the N-cyanoimino group to form an N-carbamoylinino group containing metabolite, THI amide. Resting cells of V. boronicumulans J1 degraded 62.5% of the thiacloprid at a concentration of 200 mg/L in 60 h, and 98% of the reduced thiacloprid was converted to the final metabolite thiacloprid amide. A 2.6 kb gene cluster from V. boronicumulans J1 that includes the full length of the nitrile hydratase gene was cloned and investigated by degenerate primer polymerase chain reaction (PCR) and inverse PCR. The nitrile hydratase gene has a length of 1304 bp and codes a cobalt-type nitrile hydratase with an α-subunit of 213 amino acids and a β-subunit of 221 amino ...
-
n demethylation of Neonicotinoid Insecticide acetamiprid by bacterium stenotrophomonas maltophilia cgmcc 1 1788
Biodegradation, 2008Co-Authors: Ting Chen, Yi-jun Dai, Juanfang Ding, Sheng YuanAbstract:Our previous study found that Stenotrophomonas maltophilia CGMCC 1.1788 could hydroxylate imidacloprid (IMI) to 5-hydroxy IMI. Here we first report that S. maltophilia CGMCC 1.1788 can demethylate acetamiprid (AAP) to form IM 2-1 that was characterized by HPLC-MS/MS and NMR. IM 2-1 retained only 10.5% contact activity and 13.1% oral activity of AAP against horsebean aphid. Time course of biotransformation under existing of sucrose revealed that 58.9% of AAP disappeared, but only 16.7% of reduced AAP was transformed to IM 2-1, after 8 days. Both demethylation and degradation of AAP contribute to the weak bioefficacy of AAP in soil application. The differences in metabolism and detoxification pathways between AAP and IMI are probably originated from the structural differences of these Insecticides.
Maj Rundlof - One of the best experts on this subject based on the ideXlab platform.
-
seed coating with a Neonicotinoid Insecticide negatively affects wild bees
Nature, 2015Co-Authors: Maj Rundlof, Georg K.s. Andersson, Veronica Hederström, Lina Herbertsson, Björn K. Klatt, Thorsten R. Pedersen, Ove Jonsson, Ingemar Fries, Riccardo Bommarco, Johanna YourstoneAbstract:Neonicotinoid seed coating is associated with reduced density of wild bees, as well as reduced nesting of solitary bees and reduced colony growth and reproduction of bumblebees, but appears not to affect honeybees. Reports that Neonicotinoid Insecticides have adverse effects on bee populations remain controversial. Some studies have been criticized as using unrealistically high Insecticide dosages or conditions far removed from those in the field, and it has been suggested that bees might be able to detect the Insecticides and avoid treated crops. Two papers in this issue of Nature present results that fill some of the gaps in our knowledge. In laboratory experiments Sebastien Kessler et al. use field-level doses of three commonly used Neonicotinoids — clothianidin, imidacloprid and thiamethoxam — to show that both honeybees and bumblebees are able to detect their presence. However, the bees do not avoid Neonicotinoid-treated food and may even prefer it. Maj Rundlof et al. sowed oilseed rape with and without a clothianidin seed coating in matched and replicated agricultural landscapes. They found the seed coating to be associated with reduced density of wild bees, as well as reduced nesting of solitary bees and reduced colony growth of bumblebees, but they did not detect an effect on honeybees. Understanding the effects of Neonicotinoid Insecticides on bees is vital because of reported declines in bee diversity and distribution1,2,3 and the crucial role bees have as pollinators in ecosystems and agriculture4. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants5, and the European Union has therefore introduced a moratorium on three Neonicotinoids as seed coatings in flowering crops that attract bees6. The moratorium has been criticized for being based on weak evidence7, particularly because effects have mostly been measured on bees that have been artificially fed Neonicotinoids8,9,10,11. Thus, the key question is how Neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes11,12,13. Here we show that a commonly used Insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an Insecticide containing a combination of the Neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees1,2,3 may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees.
-
Seed coating with a Neonicotinoid Insecticide negatively affects wild bees
Nature, 2015Co-Authors: Maj Rundlof, Georg K.s. Andersson, Veronica Hederström, Lina Herbertsson, Björn K. Klatt, Thorsten R. Pedersen, Ove Jonsson, Ingemar Fries, Riccardo Bommarco, Johanna YourstoneAbstract:Understanding the effects of Neonicotinoid Insecticides on bees is vital because of reported declines in bee diversity and distri- bution1–3 and the crucial role bees have as pollinators in ecosystems and agriculture4 . Neonicotinoids are suspected to pose an unac- ceptable risk to bees, partly because of their systemic uptake in plants5 , and the European Union has therefore introduced a mora- torium on three Neonicotinoids as seed coatings in flowering crops that attract bees6 . The moratorium has been criticized for being based on weak evidence7 , particularly because effects have mostly been measured on bees that have been artificially fed neonicoti- noids8–11 . Thus, the key question is how Neonicotinoids influence bees, and wild bees in particular, in real-world agricultural land- scapes11–13 . Here we show that a commonly used Insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an Insecticide containing a combina- tion of the Neonicotinoid clothianidin and the non-systemic pyre- throid b-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees1–3 may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees
Xiyue Zhao - One of the best experts on this subject based on the ideXlab platform.
-
impact of the novel Neonicotinoid Insecticide paichongding on bacterial communities in yellow loam and huangshi soils
Environmental Science and Pollution Research, 2016Co-Authors: Zhiqiang Cai, Jing Wang, Jinyan Cai, Guanghua Yang, Xiyue ZhaoAbstract:Insecticides are widely sprayed in modern agriculture for ensuring the crop yield, which could also lead to contamination and Insecticide residue in soils. Paichongding (IPP) is a novel Neonicotinoid Insecticide and was developed recently in China. Soil bacterial community, diversity, and community composition vary widely depending on environmental factors. As for now, little is known about bacterial species thriving, bacterial community diversity, and structure in IPP-spraying soils. In present study, IPP degradation in yellow loam and Huangshi soils was investigated, and bacterial communities and diversity were examined in soil without IPP spray and with IPP spray through pyrosequencing of 16S ribosomal RNA (rRNA) gene amplicons. The degradation ratio of IPP at 60 days after treatment (DAT) reached 51.22 and 34.01 % in yellow loam and Huangshi soil, respectively. A higher richness of operational taxonomic units (OTUs) was found in yellow loam soil (867 OTUs) and Huangshi soil (762 OTUs) without IPP spray while OUTs were relatively low in IPP-spraying soils. The community composition also differed both in phyla and genus level between these two environmental conditions. Proteobacteria, Firmicutes, Planctomycetes, Chloroflexi, Armatimonadetes, and Chlorobi were stimulated to increase after IPP application, while IPP inhibited the phyla of Bacteroidetes, Actinobacteria, and Acidobacteria.
-
aerobic biodegradation kinetics and pathway of the novel cis nitromethylene Neonicotinoid Insecticide paichongding in yellow loam and huangshi soils
Applied Soil Ecology, 2016Co-Authors: Zhiqiang Cai, Yan Rong, Jie Chen, Jing Wang, Wenjie Zhang, Xiyue ZhaoAbstract:Abstract Biodegradation of Paichongding (IPP), a recently developed cis -nitromethylene Neonicotinoid Insecticide, was investigated in two different soils under aerobic condition. IPP degradation rate was strongly affected by soil physic-chemical characteristics and the inoculation of IPP-degrading bacteria. Inoculation of IPP-degrading bacteria can increase degradation rate and decrease DT50 (half-life value). The removal ratio of RR-IPP, SS-IPP, SR-IPP and RS-IPP at 60 days after treatment (DAT) reached 30.17%, 28.06%, 51.48% and 45.76% in Yellow clayed soil (S1), 20.04%, 19.78%, 36.22% and 40.59% in Huangshi soil (S2), respectively. DT50 of IPP in S1 and S2 decreased after inoculation of Sphingobacterium sp. M3-1. Furthermore, based on the identified eight metabolites (M1–M8) by LC–MS/MS and their behavior, a biodegradation pathway of IPP in soils was proposed. New metabolites, M4, M6 and M7 were observed and determined in soils. Biodegradation of IPP involved continuous biocatalytic reactions such as nitro reduction and elimination, hydrolysis, C-N cleavage, de-methyl, and ether cleavage reactions. Finally, IPP was bio-transformed into M7 and M8.
-
effects of the novel cis nitromethylene Neonicotinoid Insecticide paichongding on enzyme activities and microorganisms in yellow loam and huangshi soils
Environmental Science and Pollution Research, 2016Co-Authors: Zhiqiang Cai, Yan Rong, Jie Chen, Jing Wang, Wenjie Zhang, Xiyue ZhaoAbstract:Soil enzyme activity and microbial population play important roles in maintaining soil fertility and ensure crop yield. Paichongding (IPP) is a novel cis-nitromethylene Neonicotinoid Insecticide, which was recently developed in China. In this study, in order to better understand IPP ecological toxicity, the impact of IPP on soil enzyme activity and microbial population in soils was investigated. The results showed that, urease activity was inhibited by IPP before 75 days incubation, after that this inhibiting effect gradually weakened. IPP had different stimulating effects on the activities of dehydrogenase, protease, and catalase. They were consistently stimulated from the initial time in soils. The results of microbial population indicated that the number of bacteria increased after IPP application compared with the control, fungal number increased before 45 days incubation and then decreased. While actinomycete number decreased during degradation period. DT50 (half-life value), k (degradation rate constant) of IPP in S1 (yellow loam soil), and S2 (Huangshi soil) were found 90 days and 173 days, 0.0077 day(-1), and 0.0040 day(-1), respectively.