Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fu...Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.展开更多
Degradation kinetics of microencapsulated chlorpyrifos （CPF-MC） in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos （CPF-E...Degradation kinetics of microencapsulated chlorpyrifos （CPF-MC） in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos （CPF-EC） in laboratory. The residual periods of CPF-MC with fortification levels of 5 and 20 mg/kg reached 120 days in soil, both of the degradation curves did not fit the first-order model, and out-capsule residues of chlorpyrifos in soil were maintained at 1.76 （±0.33） and 5.92 （±1.20） mg/kg in the period between 15 and 60 days, respectively. The degradation kinetics of CPF-EC fit the first-order model, and the residual periods of 5 and 20 mg/kg treatments were 60 days. Bacterial community structures in soil treated with two concentrations of CPF-MC showed similarity to those of the control during the test period, as seen in the band number and relative intensities of the individual band on DGGE gels （p 〉 0.05）. Fungal community structures were slightly affected in the 5 mg/kg treatments and returned to the control levels after 30 days, but initially differed significantly from control in the 20 mg/kg treatments （p 〈 0.05） and did not recover to control levels until 90 days later. The CPF-EC significantly altered microbial community structures （p 〈 0.05） and effects did not disappear until 240 days later. The results indicated that the microcapsule technology prolonged the residue periods of chlorpyrifos in soil whereas it decreased its side-effects on soil microbes as compared with the emulsifiable concentration formulation.展开更多
文摘Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.
基金supported by the National High Technology R&D Program of China (Nos. 2013AA102804D, 2012AA06A204)the National Natural Science Foundation of China (Nos. 21177111, 42171489)+2 种基金the Key Scientific and Technological Innovation Team Program of Zhejiang Province (No. 2010R50028)the Zhejiang Provincial Natural Science Foundation (No. LZ13D010001)the Hangzhou Science and Technology Development Item (No. 20110232B11)
文摘Degradation kinetics of microencapsulated chlorpyrifos （CPF-MC） in soil and its influence on soil microbial community structures were investigated by comparing with emulsifiable concentration of chlorpyrifos （CPF-EC） in laboratory. The residual periods of CPF-MC with fortification levels of 5 and 20 mg/kg reached 120 days in soil, both of the degradation curves did not fit the first-order model, and out-capsule residues of chlorpyrifos in soil were maintained at 1.76 （±0.33） and 5.92 （±1.20） mg/kg in the period between 15 and 60 days, respectively. The degradation kinetics of CPF-EC fit the first-order model, and the residual periods of 5 and 20 mg/kg treatments were 60 days. Bacterial community structures in soil treated with two concentrations of CPF-MC showed similarity to those of the control during the test period, as seen in the band number and relative intensities of the individual band on DGGE gels （p 〉 0.05）. Fungal community structures were slightly affected in the 5 mg/kg treatments and returned to the control levels after 30 days, but initially differed significantly from control in the 20 mg/kg treatments （p 〈 0.05） and did not recover to control levels until 90 days later. The CPF-EC significantly altered microbial community structures （p 〈 0.05） and effects did not disappear until 240 days later. The results indicated that the microcapsule technology prolonged the residue periods of chlorpyrifos in soil whereas it decreased its side-effects on soil microbes as compared with the emulsifiable concentration formulation.
