The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium e...The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium extraction with over 90% at the Fe/S ratio of 5:0.5, 5:1 and 5:5, while poor extraction(<46%) at the Fe/S ratio of 5:0 and 5:10.Furthermore, the bacterial community analysis based on species-specific gyrB numbers indicated that, absent sulfur or excessive sulfur would be not conducive to the synergistic growth for A. ferrooxidans and A. thiooxidans, and then not conducive to the uranium dissolution. Meanwhile, the sulfur-oxidizers could play an important role in the process of uranium synergistic bioleaching by mixed bacterial consortia. Additionally, the characteristics of mineral residue was detected by SEM-EDS. The results showed appropriate sulfur dosage would change the structure and improve the porosity of passivation substance. Lastly, the uranium dissolution kinetics and biochemical reaction mechanism was analyzed. It indicated that the biochemical reaction coupling iron and sulfur had a pleiotropic effect on the uranium dissolution from the ore particles, appropriate Fe/S ratio is the key factor for uranium bioleaching by chemoautotrophic acidophiles.展开更多
Arsenic(As)speciation transformation in acid mine drainage(AMD)is comprehensively affected by biological and abiotic factors,such as microbially mediated Fe/S redox reactions and changes in environmental conditions(pH...Arsenic(As)speciation transformation in acid mine drainage(AMD)is comprehensively affected by biological and abiotic factors,such as microbially mediated Fe/S redox reactions and changes in environmental conditions(pH and oxidation-reduction potential).However,their combined impacts on arsenic speciation transformation remain poorly studied.Therefore,we explored arsenic transformation and immobilization during pyrite dissolution mediated by AMD enrichment culture under different acidic pH conditions.The results for incubation and mineralogical transformation of solid residues show that in the presence of AMD enrichment culture,pH 2.0,2.5,and 3.0 are more conducive to the formation of jarosites and ferric arsenate,which could immobilize high quantities of dissolved arsenic by adsorption and coprecipitation.The pH conditions significantly affect the initial adsorption of microbial cells to the minerals and the evolution of microbial community structure,further infuencing the biodissolution of pyrite and the release and oxidation process of Fe/S.The results of Fe/S/As speciation transformation of the solid residues show that the transformation of Fe,S,and As in solution is mainly regulated by pH and potential values,which imposed significantly different effects on the formation of secondary minerals and thus arsenic oxidation and immobilization.The above results indicated that arsenic transformation is closely related to the Fe/S oxidation associated with pyrite bio-oxidation,and this correlation is critically regulated by the pH conditions of the system.展开更多
本研究旨在探究线粒体复合物Ⅰ(ComplexⅠ,CⅠ)的核心结构蛋白NADH脱氢酶铁硫蛋白4(NADH Dehydrogenase(Ubiquinone)Fe S protein 4,NDUFS4)在涡虫成体干细胞功能维持与神经再生过程中的作用。通过克隆获得东亚三角涡虫(Dugesia sp.)ndu...本研究旨在探究线粒体复合物Ⅰ(ComplexⅠ,CⅠ)的核心结构蛋白NADH脱氢酶铁硫蛋白4(NADH Dehydrogenase(Ubiquinone)Fe S protein 4,NDUFS4)在涡虫成体干细胞功能维持与神经再生过程中的作用。通过克隆获得东亚三角涡虫(Dugesia sp.)ndufs4基因并进行序列及结构预测分析,结果显示其编码蛋白在保守结构域和关键氨基酸位点高度保守。采用RNA干扰技术持续敲降ndufs4表达,测定再生涡虫胚基(blastema)生长速率,并结合原位杂交与免疫组织化学等实验技术检测成体干细胞(Neoblasts)的增殖与分化、神经再生情况。结果表明,ndufs4敲降导致涡虫再生速率显著减慢,神经再生明显受损;同时,干细胞标记基因表达水平下降,干细胞分化进程受阻。上述结果说明,NDUFS4是维持涡虫成体干细胞群体功能及促进神经再生的必需蛋白,在生物再生中发挥重要调控功能。展开更多
基金Project(51804165) supported by the National Natural Science Foundation of ChinaProject(2018JJ3441) supported by the Natural Science Foundation of Hunan Province,China。
文摘The role of Fe/S ratios(ω, g/g) in the uranium bioleaching from a complex uranium ore by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans consortium was investigated. The results showed good uranium extraction with over 90% at the Fe/S ratio of 5:0.5, 5:1 and 5:5, while poor extraction(<46%) at the Fe/S ratio of 5:0 and 5:10.Furthermore, the bacterial community analysis based on species-specific gyrB numbers indicated that, absent sulfur or excessive sulfur would be not conducive to the synergistic growth for A. ferrooxidans and A. thiooxidans, and then not conducive to the uranium dissolution. Meanwhile, the sulfur-oxidizers could play an important role in the process of uranium synergistic bioleaching by mixed bacterial consortia. Additionally, the characteristics of mineral residue was detected by SEM-EDS. The results showed appropriate sulfur dosage would change the structure and improve the porosity of passivation substance. Lastly, the uranium dissolution kinetics and biochemical reaction mechanism was analyzed. It indicated that the biochemical reaction coupling iron and sulfur had a pleiotropic effect on the uranium dissolution from the ore particles, appropriate Fe/S ratio is the key factor for uranium bioleaching by chemoautotrophic acidophiles.
基金supported by the National Natural Science Foundation of China (NSFC) (No.41830318)the Joint Funds of the NSFC-DFG (No.51861135305)。
文摘Arsenic(As)speciation transformation in acid mine drainage(AMD)is comprehensively affected by biological and abiotic factors,such as microbially mediated Fe/S redox reactions and changes in environmental conditions(pH and oxidation-reduction potential).However,their combined impacts on arsenic speciation transformation remain poorly studied.Therefore,we explored arsenic transformation and immobilization during pyrite dissolution mediated by AMD enrichment culture under different acidic pH conditions.The results for incubation and mineralogical transformation of solid residues show that in the presence of AMD enrichment culture,pH 2.0,2.5,and 3.0 are more conducive to the formation of jarosites and ferric arsenate,which could immobilize high quantities of dissolved arsenic by adsorption and coprecipitation.The pH conditions significantly affect the initial adsorption of microbial cells to the minerals and the evolution of microbial community structure,further infuencing the biodissolution of pyrite and the release and oxidation process of Fe/S.The results of Fe/S/As speciation transformation of the solid residues show that the transformation of Fe,S,and As in solution is mainly regulated by pH and potential values,which imposed significantly different effects on the formation of secondary minerals and thus arsenic oxidation and immobilization.The above results indicated that arsenic transformation is closely related to the Fe/S oxidation associated with pyrite bio-oxidation,and this correlation is critically regulated by the pH conditions of the system.
文摘本研究旨在探究线粒体复合物Ⅰ(ComplexⅠ,CⅠ)的核心结构蛋白NADH脱氢酶铁硫蛋白4(NADH Dehydrogenase(Ubiquinone)Fe S protein 4,NDUFS4)在涡虫成体干细胞功能维持与神经再生过程中的作用。通过克隆获得东亚三角涡虫(Dugesia sp.)ndufs4基因并进行序列及结构预测分析,结果显示其编码蛋白在保守结构域和关键氨基酸位点高度保守。采用RNA干扰技术持续敲降ndufs4表达,测定再生涡虫胚基(blastema)生长速率,并结合原位杂交与免疫组织化学等实验技术检测成体干细胞(Neoblasts)的增殖与分化、神经再生情况。结果表明,ndufs4敲降导致涡虫再生速率显著减慢,神经再生明显受损;同时,干细胞标记基因表达水平下降,干细胞分化进程受阻。上述结果说明,NDUFS4是维持涡虫成体干细胞群体功能及促进神经再生的必需蛋白,在生物再生中发挥重要调控功能。
