Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with a...Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with avermectins may contaminate various bodies of water, and accumulated to certain concentrations to impact the development of aquatic animals. Here, we tested the genotoxicity of three avermectins （abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB） on Polypedates megacephalus tadpoles by the alkaline single-cell gel electrophoresis assay. Tadpoles were treated for 48 h in the laboratory with different concentrations of these three agents, 0.006, 0.012, 0.018, 0.024, 0.030 mg/L for ABM, 0.003, 0.006, 0.009, 0.012, 0.015 mg/L for IVM and 0.04, 0.06, 0.08, 0.10, 0.12 mg/L for EMB, and then measured their DNA damage by the Comet assay tail factor %. The concentrations of resulted in highly significant increases in DNA damage of the tadpoles were found above the concentration threshold of 0.012 mg/ L ABM, 0.003 mg/L IVM and 0.06 mg/L EMB and linear correlations between the intensity of DNA damage and the concentrations of these three avermectins. Our results showed clearly that avermectins caused dose dependent DNA damage on amphibian tadpoles, and there might be a control on the misuse of avermectins.展开更多
The adsorption of biopesticide avermectins onto activated carbon from ethanol solution with different initial concentrations at 303.15 K was performed. The obtained equilibrium and kinetic data of the adsorption proce...The adsorption of biopesticide avermectins onto activated carbon from ethanol solution with different initial concentrations at 303.15 K was performed. The obtained equilibrium and kinetic data of the adsorption process were assayed to evaluate the adsorption potential of activated carbon for avermectins. The results show that the activated carbon is effective for the adsorption of avermectins. Moreover, the adsorption of avermectins onto activated carbon agrees with Langmuir isotherm model, while pseudo-second-order kinetics model is better fitable for such adsorption process. In addition, activated carbon can efficiently protect adsorbed avermectins from photodegradation.展开更多
The 2015 Nobel Prize in Physiology or Medicine has been awarded to avermectins and artemisinin,respectively.Avermectins produced by Streptomyces avermitilis are excellent anthelmintic and potential antibiotic agents.B...The 2015 Nobel Prize in Physiology or Medicine has been awarded to avermectins and artemisinin,respectively.Avermectins produced by Streptomyces avermitilis are excellent anthelmintic and potential antibiotic agents.Because wild-type strains only produce low levels of avermectins,much research effort has focused on improvements in avermectin production to meet the ever increasing demand for such compounds.This review describes the strategies that have been widely employed and the future prospects of synthetic biology applications in avermectin yield improvement.With the help of genome sequencing of S.avermitilis and an understanding of the avermectin biosynthetic/regulatory pathways,synthetic and systems biotechnology approaches have been applied for precision engineering.We focus on the design and synthesis of biological chassis,parts,devices,and modules from diverse microbes to reconstruct and optimize their dynamic processes,as well as predict favorable effective overproduction of avermectins by a 4Ms strategy(Mine,Model,Manipulation,and Measurement).展开更多
Avermectins,a group of polyketide natural products,are widely used as anthelmintics in agriculture.Metabolic engineering and combinatorial biosynthesis were extensively employed to improve Avermectins production and c...Avermectins,a group of polyketide natural products,are widely used as anthelmintics in agriculture.Metabolic engineering and combinatorial biosynthesis were extensively employed to improve Avermectins production and create novel Avermectin derivatives,including Ivermectin and Doramectin.It is labor intensive and time cost to genetically manipulate Avermectins producer Streptomyces avermitilis in vivo.Cloning and heterologous expression of Avermectins biosynthetic gene cluster will make it possible to tailor the cluster in vitro.We constructed a Bacterial Artificial Chromosome(BAC)library of S.avermitilis ATCC 31267 with inserted DNA fragments ranged from 100 to 130 Kb.Five recombinant BAC clones which carried the Avermectins biosynthetic gene cluster ave(81 Kb in size)were screened out from the library.Then,ave was hetero-expressed in S.lividans.Three Avermectin components,A2a,B1a and A1a were detected from the cell extracts of recombinant strains.It will facilitate the development of Avermectin derivatives by polyketide synthase domain swapping and provide functional element for Avermectins synthetic biology study.展开更多
In order to mitigate the occurrence and damage of cowpea whitefly, reduce chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design andstatistical analysi...In order to mitigate the occurrence and damage of cowpea whitefly, reduce chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design andstatistical analysis were used in field efficacy trials, to study the control effect of cowpea anthracnose by usingchemical pesticides dinotefuran, acetamiprid, pymetrozine, and bio-pesticide avermectin. The results showed that after applying 1.85% avermectin EC 375 g, 20% dinotefuran SP 600 g, 5% acetamiprid WP 600 g, and 25% pymetrozine WP 600 g （control pesticide） per hm2 once every 5-8 days, and 3 times continuously underserious autumn occurrence of greenhouse whitefly, the control efficacy was 90.9%, 97.0%, 88.0%, 93.9%respectively on the 7th day after the pesticides application; 97.4%, 92.1%, 84.2%, 89.4% respectively on the 14th day after the pesticides application; and 95.6%, 86.7%, 82.2%, 84.5%, respectively on the 20th day afterthe pesticides application. The control effects among avermectin, acetamiprid and pymetrozine were not significantly different, while the effects of avermectin and pymetrozine were significantly higher than that of acetamiprid on the 7th day. The control effects among avermectin, dinotefuran and pymetrozine were not significantly different, while significantly higher than that of acetamiprid on the 14th day. The control effect of avermectin was significantly higher than that of dinotefuran, acetamiprid and pymetrozine on the 20th day. Meanwhile, the control effect of avermectin was slightly lower, higher and much higher than that of dinotefuran on the 7th, 14th, 20th day respectively after the treatment. These results indicated that the four pesticides,especiaLly biopesticide avermectin, were ideal pesticides, which could not only be used for controlling cowpea whitefly, but also realize modern, green, organic and ecological agricultural production.展开更多
基金granted by the Natural Science Foundation of Fujian, China (2015J01124)
文摘Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with avermectins may contaminate various bodies of water, and accumulated to certain concentrations to impact the development of aquatic animals. Here, we tested the genotoxicity of three avermectins （abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB） on Polypedates megacephalus tadpoles by the alkaline single-cell gel electrophoresis assay. Tadpoles were treated for 48 h in the laboratory with different concentrations of these three agents, 0.006, 0.012, 0.018, 0.024, 0.030 mg/L for ABM, 0.003, 0.006, 0.009, 0.012, 0.015 mg/L for IVM and 0.04, 0.06, 0.08, 0.10, 0.12 mg/L for EMB, and then measured their DNA damage by the Comet assay tail factor %. The concentrations of resulted in highly significant increases in DNA damage of the tadpoles were found above the concentration threshold of 0.012 mg/ L ABM, 0.003 mg/L IVM and 0.06 mg/L EMB and linear correlations between the intensity of DNA damage and the concentrations of these three avermectins. Our results showed clearly that avermectins caused dose dependent DNA damage on amphibian tadpoles, and there might be a control on the misuse of avermectins.
基金Projects(2006AA10A203 2007AA021808) supported by the National High-Tech Research and Development Program of China
文摘The adsorption of biopesticide avermectins onto activated carbon from ethanol solution with different initial concentrations at 303.15 K was performed. The obtained equilibrium and kinetic data of the adsorption process were assayed to evaluate the adsorption potential of activated carbon for avermectins. The results show that the activated carbon is effective for the adsorption of avermectins. Moreover, the adsorption of avermectins onto activated carbon agrees with Langmuir isotherm model, while pseudo-second-order kinetics model is better fitable for such adsorption process. In addition, activated carbon can efficiently protect adsorbed avermectins from photodegradation.
基金the National Program on Key Basic Research Project(973 program,2013CB734000 and 2012CB725203)the National Natural Science Foundation of China(31170095,31000057,and 31100075)+1 种基金the Ministry of Science and Technology of the People’s Republic of China(2011ZX11102-011-11 and 2013ZX10005004-005)China Ocean Mineral Resources R&D Association(DY125-15-T-07)。
文摘The 2015 Nobel Prize in Physiology or Medicine has been awarded to avermectins and artemisinin,respectively.Avermectins produced by Streptomyces avermitilis are excellent anthelmintic and potential antibiotic agents.Because wild-type strains only produce low levels of avermectins,much research effort has focused on improvements in avermectin production to meet the ever increasing demand for such compounds.This review describes the strategies that have been widely employed and the future prospects of synthetic biology applications in avermectin yield improvement.With the help of genome sequencing of S.avermitilis and an understanding of the avermectin biosynthetic/regulatory pathways,synthetic and systems biotechnology approaches have been applied for precision engineering.We focus on the design and synthesis of biological chassis,parts,devices,and modules from diverse microbes to reconstruct and optimize their dynamic processes,as well as predict favorable effective overproduction of avermectins by a 4Ms strategy(Mine,Model,Manipulation,and Measurement).
基金This work was financially supported by the Ministry of Science and Technology of China(“973”Program 2013CB734003)the National Science Foundation of China(31670030).
文摘Avermectins,a group of polyketide natural products,are widely used as anthelmintics in agriculture.Metabolic engineering and combinatorial biosynthesis were extensively employed to improve Avermectins production and create novel Avermectin derivatives,including Ivermectin and Doramectin.It is labor intensive and time cost to genetically manipulate Avermectins producer Streptomyces avermitilis in vivo.Cloning and heterologous expression of Avermectins biosynthetic gene cluster will make it possible to tailor the cluster in vitro.We constructed a Bacterial Artificial Chromosome(BAC)library of S.avermitilis ATCC 31267 with inserted DNA fragments ranged from 100 to 130 Kb.Five recombinant BAC clones which carried the Avermectins biosynthetic gene cluster ave(81 Kb in size)were screened out from the library.Then,ave was hetero-expressed in S.lividans.Three Avermectin components,A2a,B1a and A1a were detected from the cell extracts of recombinant strains.It will facilitate the development of Avermectin derivatives by polyketide synthase domain swapping and provide functional element for Avermectins synthetic biology study.
基金Supported by Approving on the First Batch of National Modern Agriculture Demonstration District by Ministry of Agriculture([2010]No.22)Fundamental Research Funds for the Central Universities(XDJK2016A020)~~
文摘In order to mitigate the occurrence and damage of cowpea whitefly, reduce chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design andstatistical analysis were used in field efficacy trials, to study the control effect of cowpea anthracnose by usingchemical pesticides dinotefuran, acetamiprid, pymetrozine, and bio-pesticide avermectin. The results showed that after applying 1.85% avermectin EC 375 g, 20% dinotefuran SP 600 g, 5% acetamiprid WP 600 g, and 25% pymetrozine WP 600 g （control pesticide） per hm2 once every 5-8 days, and 3 times continuously underserious autumn occurrence of greenhouse whitefly, the control efficacy was 90.9%, 97.0%, 88.0%, 93.9%respectively on the 7th day after the pesticides application; 97.4%, 92.1%, 84.2%, 89.4% respectively on the 14th day after the pesticides application; and 95.6%, 86.7%, 82.2%, 84.5%, respectively on the 20th day afterthe pesticides application. The control effects among avermectin, acetamiprid and pymetrozine were not significantly different, while the effects of avermectin and pymetrozine were significantly higher than that of acetamiprid on the 7th day. The control effects among avermectin, dinotefuran and pymetrozine were not significantly different, while significantly higher than that of acetamiprid on the 14th day. The control effect of avermectin was significantly higher than that of dinotefuran, acetamiprid and pymetrozine on the 20th day. Meanwhile, the control effect of avermectin was slightly lower, higher and much higher than that of dinotefuran on the 7th, 14th, 20th day respectively after the treatment. These results indicated that the four pesticides,especiaLly biopesticide avermectin, were ideal pesticides, which could not only be used for controlling cowpea whitefly, but also realize modern, green, organic and ecological agricultural production.
