A new bacterial strain DMT-7 capable of selectively desulfurizing dibenzothiophene（DBT） was isolated from diesel contaminated soil.The DMT-7 was characterized and identified as Lysinibacillus sphaericus DMT-7（NCBI ...A new bacterial strain DMT-7 capable of selectively desulfurizing dibenzothiophene（DBT） was isolated from diesel contaminated soil.The DMT-7 was characterized and identified as Lysinibacillus sphaericus DMT-7（NCBI GenBank Accession No.GQ496620） using 16S rDNA gene sequence analysis.The desulfurized product of DBT,2-hydroxybiphenyl（2HBP）,was identified and confirmed by high performance liquid chromatography analysis and gas chromatography-mass spectroscopy analysis respectively.The desulfurization kinetics revealed that DMT-7 started desulfurization of DBT into 2HBP after the lag phase of 24 hr,exponentially increasing the accumulation of 2HBP up to 15 days leading to approximately 60% desulfurization of the DBT.However,further growth resulted into DBT degradation.The induced culture of DMT-7 showed shorter lag phase of 6 hr and early onset of stationary phase within 10 days for desulfurization as compared to that of non-induced culture clearly indicating the inducibility of the desulfurization pathway of DMT-7.In addition,Lysinibacillus sphaericus DMT-7 also possess the ability to utilize broad range of substrates as sole source of sulfur such as benzothiophene,3,4-benzo DBT,4,6-dimethyl DBT,and 4,6-dibutyl DBT.Therefore,Lysinibacillus sphaericus DMT-7 could serve as model system for efficient biodesulfurization of diesel and petrol.展开更多
[Objective] The paper was to explore the antigen harvest time of Mycoplasrna bovis and the antigen quantification alternative method. [Method] M. bovis 08M strain was inoculated in the Thiaueourt＇s medium containing ...[Objective] The paper was to explore the antigen harvest time of Mycoplasrna bovis and the antigen quantification alternative method. [Method] M. bovis 08M strain was inoculated in the Thiaueourt＇s medium containing 10% horse serum. Four growth curves were plotted by simultaneously measuring color change units （CCU）, colony forming units （CFU）, protein concentration and nucleic acid levels within 110 h. [ Result] The growth of M. bovis was divided into four phases： the longarithmie phase appeared after being cultured for 10 h; the stationary phase appeared at 30 h with the highest number of viable cells up to 1. 0× 108 CCU/mL and 7.7 × 107 CCU/mL, respectively; and the decline phase started at 75 h. The protein concentration afM. bov/s increased rapidly from 15 to 35 h, reached 72.06 μg/mL at 35 h, then maintained at 53.38 - 70.65 μg/mL. The nucleic acid levels of M. bov/s increased rapidly from 15 h, and the cycle threshold （Ct） values were maintained between 15, 32 and 17.84 after 25 h. [ Conclusion] There was a good correlation between the protein concentration and variable count of M. bov/s at the early stationary phase, which was the best time period to harvest antigen. The protein concentration determination could be an alternative method to quantify antigen content of M. bovis when preparing inactivated M. boviz vaccine. Key words Mycoplasma boyis; Antigen quantification; Color change units; Colony forming units; Protein concentration; Nucleic acid content展开更多
文摘A new bacterial strain DMT-7 capable of selectively desulfurizing dibenzothiophene（DBT） was isolated from diesel contaminated soil.The DMT-7 was characterized and identified as Lysinibacillus sphaericus DMT-7（NCBI GenBank Accession No.GQ496620） using 16S rDNA gene sequence analysis.The desulfurized product of DBT,2-hydroxybiphenyl（2HBP）,was identified and confirmed by high performance liquid chromatography analysis and gas chromatography-mass spectroscopy analysis respectively.The desulfurization kinetics revealed that DMT-7 started desulfurization of DBT into 2HBP after the lag phase of 24 hr,exponentially increasing the accumulation of 2HBP up to 15 days leading to approximately 60% desulfurization of the DBT.However,further growth resulted into DBT degradation.The induced culture of DMT-7 showed shorter lag phase of 6 hr and early onset of stationary phase within 10 days for desulfurization as compared to that of non-induced culture clearly indicating the inducibility of the desulfurization pathway of DMT-7.In addition,Lysinibacillus sphaericus DMT-7 also possess the ability to utilize broad range of substrates as sole source of sulfur such as benzothiophene,3,4-benzo DBT,4,6-dimethyl DBT,and 4,6-dibutyl DBT.Therefore,Lysinibacillus sphaericus DMT-7 could serve as model system for efficient biodesulfurization of diesel and petrol.
基金Supported by National Key Technology R&D Program(2015BAD12B02)Key Technology R&D Program of Gansu Province(1204NKCA071)Science and Technology Plan of Chengguan District,Lanzhou City(2012-2-1)
文摘[Objective] The paper was to explore the antigen harvest time of Mycoplasrna bovis and the antigen quantification alternative method. [Method] M. bovis 08M strain was inoculated in the Thiaueourt＇s medium containing 10% horse serum. Four growth curves were plotted by simultaneously measuring color change units （CCU）, colony forming units （CFU）, protein concentration and nucleic acid levels within 110 h. [ Result] The growth of M. bovis was divided into four phases： the longarithmie phase appeared after being cultured for 10 h; the stationary phase appeared at 30 h with the highest number of viable cells up to 1. 0× 108 CCU/mL and 7.7 × 107 CCU/mL, respectively; and the decline phase started at 75 h. The protein concentration afM. bov/s increased rapidly from 15 to 35 h, reached 72.06 μg/mL at 35 h, then maintained at 53.38 - 70.65 μg/mL. The nucleic acid levels of M. bov/s increased rapidly from 15 h, and the cycle threshold （Ct） values were maintained between 15, 32 and 17.84 after 25 h. [ Conclusion] There was a good correlation between the protein concentration and variable count of M. bov/s at the early stationary phase, which was the best time period to harvest antigen. The protein concentration determination could be an alternative method to quantify antigen content of M. bovis when preparing inactivated M. boviz vaccine. Key words Mycoplasma boyis; Antigen quantification; Color change units; Colony forming units; Protein concentration; Nucleic acid content
