3-Methylindole(skatole)is regarded as one of the most offensive compounds in odor emission.Biodegradation is feasible for skatole removal but the functional species and genes responsible for skatole degradation remain...3-Methylindole(skatole)is regarded as one of the most offensive compounds in odor emission.Biodegradation is feasible for skatole removal but the functional species and genes responsible for skatole degradation remain enigmatic.In this study,an efficient aerobic skatole-degrading consortium was obtained.Rhodococcus and Pseudomonas were identified as the two major and active populations by integrated metagenomic and metatranscriptomic analyses.Bioinformatic analyses indicated that the skatole downstream degradation wasmainly via the catechol pathway,and upstream degradation was likely catalyzed by the aromatic ring-hydroxylating oxygenase and flavin monooxygenase.Genome binning and gene analyses indicated that Pseudomonas,Pseudoclavibacter,and Raineyella should cooperate with Rhodococcus for the skatole degradation process.Moreover,a pure strain Rhodococcus sp.DMU1 was successfully obtained which could utilize skatole as the sole carbon source.Complete genome sequencing showed that strain DMU1 was the predominant population in the consortium.Further crude enzyme and RT-qPCR assays indicated that strain DMU1 degraded skatole through the catechol ortho-cleavage pathway.Collectively,our results suggested that synergistic degradation of skatole in the consortium should be performed by diverse bacteria with Rhodococcus as the primary degrader,and the degradation mainly proceeded via the catechol pathway.展开更多
This paper reviews the usage and emissions of endosulfan, the newest member of the persistent organic pollutants （POPs）, in China, and its fate and behavior in Chinese environment. Endosulfan usage in China has been...This paper reviews the usage and emissions of endosulfan, the newest member of the persistent organic pollutants （POPs）, in China, and its fate and behavior in Chinese environment. Endosulfan usage in China has been estimated to be approximately 25700 t between 1994 and 2004. Concentrations of endosulfan in different environ- mental compartments in China, such as air, soil, water, and biota, but focusing at air and surface soil, have been summarized. Concentrations of total endosulfan in surface soil across China were ranged from below detection limit （BDL） to 19000 pg.g^-1 dry weight （dw）, with geometric mean of 120pg.g^-1dw. The results indicated that endo- sulfan sulfate had highest concentration in Chinese soil, followed by r- and α-endosulfan. Air concentrations of endosulfan in China were ranged 0-340 pg.m3 for a- endosulfan and 0-121 pg. m--3 for β-endosulfan, with high concentrations occurred in the cotton production areas. Gridded usage inventories of endosulfan on a fine gridded system with a 1/4° longitude by 1/6° latitude resolution were compiled, from which, emission to air and residues in soil of endosulfan were calculated in each grid by using a modified simplified gridded pesticide emission and residue model （SGPERM）, an integrated modeling system combining mathematical model, database management system, and geographic information system. Total emissions were around 10800 t from 1994 to 2004. Based on the emission and residue inventories, concentrations of α- and β- endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell, which are in general consistent with the published monitoring data.展开更多
基金supported by the National Natural Science Foundation of China(No.32170121)the Fundamental Research Funds for the Central Universities(No.3132022159).
文摘3-Methylindole(skatole)is regarded as one of the most offensive compounds in odor emission.Biodegradation is feasible for skatole removal but the functional species and genes responsible for skatole degradation remain enigmatic.In this study,an efficient aerobic skatole-degrading consortium was obtained.Rhodococcus and Pseudomonas were identified as the two major and active populations by integrated metagenomic and metatranscriptomic analyses.Bioinformatic analyses indicated that the skatole downstream degradation wasmainly via the catechol pathway,and upstream degradation was likely catalyzed by the aromatic ring-hydroxylating oxygenase and flavin monooxygenase.Genome binning and gene analyses indicated that Pseudomonas,Pseudoclavibacter,and Raineyella should cooperate with Rhodococcus for the skatole degradation process.Moreover,a pure strain Rhodococcus sp.DMU1 was successfully obtained which could utilize skatole as the sole carbon source.Complete genome sequencing showed that strain DMU1 was the predominant population in the consortium.Further crude enzyme and RT-qPCR assays indicated that strain DMU1 degraded skatole through the catechol ortho-cleavage pathway.Collectively,our results suggested that synergistic degradation of skatole in the consortium should be performed by diverse bacteria with Rhodococcus as the primary degrader,and the degradation mainly proceeded via the catechol pathway.
文摘This paper reviews the usage and emissions of endosulfan, the newest member of the persistent organic pollutants （POPs）, in China, and its fate and behavior in Chinese environment. Endosulfan usage in China has been estimated to be approximately 25700 t between 1994 and 2004. Concentrations of endosulfan in different environ- mental compartments in China, such as air, soil, water, and biota, but focusing at air and surface soil, have been summarized. Concentrations of total endosulfan in surface soil across China were ranged from below detection limit （BDL） to 19000 pg.g^-1 dry weight （dw）, with geometric mean of 120pg.g^-1dw. The results indicated that endo- sulfan sulfate had highest concentration in Chinese soil, followed by r- and α-endosulfan. Air concentrations of endosulfan in China were ranged 0-340 pg.m3 for a- endosulfan and 0-121 pg. m--3 for β-endosulfan, with high concentrations occurred in the cotton production areas. Gridded usage inventories of endosulfan on a fine gridded system with a 1/4° longitude by 1/6° latitude resolution were compiled, from which, emission to air and residues in soil of endosulfan were calculated in each grid by using a modified simplified gridded pesticide emission and residue model （SGPERM）, an integrated modeling system combining mathematical model, database management system, and geographic information system. Total emissions were around 10800 t from 1994 to 2004. Based on the emission and residue inventories, concentrations of α- and β- endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell, which are in general consistent with the published monitoring data.
