The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K+ growth conditions. The effects of external pH and Na+ on the accumulation of ce-sium were also studied, and the mechani...The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K+ growth conditions. The effects of external pH and Na+ on the accumulation of ce-sium were also studied, and the mechanism involved was discussed. K+ regimes played an important role in the accumulation of cesium by the strain TibetanG6. The quantity of cesium accumulated (24 h) was much higher in K+-deficient regime than that in K+-sufficient regime. The pH and Na+ had different effects on the accumulation of cesium in the two K+ regimes. IR spectra analyses indicated that the biosorption is a process of homeostasis with cesium initially accumulated on the cell wall.展开更多
Thermus thermophilus is an attractive species in the bioindustry due to its valuable natural products,abundant thermophilic enzymes,and promising fermentation capacities.However,efficient and versatile genome editing ...Thermus thermophilus is an attractive species in the bioindustry due to its valuable natural products,abundant thermophilic enzymes,and promising fermentation capacities.However,efficient and versatile genome editing tools are not available for this species.In this study,we developed an efficient genome editing tool for T.thermophilus HB27 based on its endogenous type IB,I-C,and III-A/B CRISPR-Cas systems.First,we systematically characterized the DNA interference capabilities of the different types of the native CRISPR-Cas systems in T.thermophilus HB27.We found that genomic manipulations such as gene deletion,mutation,and in situ tagging could be easily implemented by a series of genome-editing plasmids carrying an artificial self-targeting mini-CRISPR and a donor DNA responsible for the recombinant recovery.We also compared the genome editing efficiency of different CRISPR-Cas systems and the editing plasmids with donor DNAs of different lengths.Additionally,we developed a reporter gene system for T.thermophilus based on a heat-stableβ-galactosidase gene TTP0042,and constructed an engineered strain with a high production capacity of superoxide dismutases by genome modification.展开更多
Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither t...Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither the denitrification potential nor the evolutionary history of denitrification genes in the genus Thermus or phylum Deinococcota is well understood.Here,we performed a comparative analysis of 23 Thermus genomes and identified denitrification genes in 15 Thermus strains.We confirmed that Thermus harbors an incomplete denitrification pathway as none of the strains contain the nosZ gene.Ancestral character state reconstructions and phylogenetic analyses showed that narG,nirS,and norB genes were acquired by the last common ancestor of Thermales and were inherited vertically.In contrast,nirK of Thermales was acquired via two distinct horizontal gene transfers from Proteobacteria to the genus Caldithermus and from an unknown donor to the common ancestor of all known Thermus species except Thermus filiformis.This study expands our understanding of the genomic potential for incomplete denitrification in Thermus,revealing a largely vertical evolutionary history of the denitrification pathway in the Thermaceae,and supporting the important role for Thermus as an important heterotrophic denitrifier in geothermal environments.展开更多
MATTt （a thermostable methionine adenosyl- transferase from Thermus thermophilus HB27） was over- expressed in Escherchia coli and purified using Ni-NTA affinity column. The enzymatic activity of MATTt was investigat...MATTt （a thermostable methionine adenosyl- transferase from Thermus thermophilus HB27） was over- expressed in Escherchia coli and purified using Ni-NTA affinity column. The enzymatic activity of MATTt was investigated in a temperature range from 30 ℃ to 90 ℃, showing that MATTt exhibited a high enzymatic activity and good thermostability at 80 ℃. Circular dichroism spectra reveals that MATTt contains high portion of β- sheet structures contributing to the thermostability of MATTt. The kinetic parameter, Km is 4.19 mmoFL and 1.2 mmol/L for ATP and methionine, respectively. MATTt exhibits the highest enzymatic activity at pH 8. Cobalt （Co^2＋） and zinc ion （Zn^2＋） enhances remarkably the activity of MATTt compared to the magnesium ion （Mg^2＋）. All these results indicated that the thermostable MATTt has great potential for industry applications.展开更多
文摘The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K+ growth conditions. The effects of external pH and Na+ on the accumulation of ce-sium were also studied, and the mechanism involved was discussed. K+ regimes played an important role in the accumulation of cesium by the strain TibetanG6. The quantity of cesium accumulated (24 h) was much higher in K+-deficient regime than that in K+-sufficient regime. The pH and Na+ had different effects on the accumulation of cesium in the two K+ regimes. IR spectra analyses indicated that the biosorption is a process of homeostasis with cesium initially accumulated on the cell wall.
基金the National Natural Science Foundation of China(32170096)the Fundamental Research Funds for the Central Universities(2662022S KPY001)Cooperation Fund of Huazhong Agricultural University-Agricultural Genomics Institute at Shenzhen(CAAS)(SZYJY2021002).
文摘Thermus thermophilus is an attractive species in the bioindustry due to its valuable natural products,abundant thermophilic enzymes,and promising fermentation capacities.However,efficient and versatile genome editing tools are not available for this species.In this study,we developed an efficient genome editing tool for T.thermophilus HB27 based on its endogenous type IB,I-C,and III-A/B CRISPR-Cas systems.First,we systematically characterized the DNA interference capabilities of the different types of the native CRISPR-Cas systems in T.thermophilus HB27.We found that genomic manipulations such as gene deletion,mutation,and in situ tagging could be easily implemented by a series of genome-editing plasmids carrying an artificial self-targeting mini-CRISPR and a donor DNA responsible for the recombinant recovery.We also compared the genome editing efficiency of different CRISPR-Cas systems and the editing plasmids with donor DNAs of different lengths.Additionally,we developed a reporter gene system for T.thermophilus based on a heat-stableβ-galactosidase gene TTP0042,and constructed an engineered strain with a high production capacity of superoxide dismutases by genome modification.
基金supported by funding from the National Natural Science Foundation of China(Nos.91951205,92051108,31850410475,and 31970122)the National Science and Technology Fundamental Resources Investigation Program of China(2021FY100900)the U.S.National Science Foundation(DEB 1557042 and DEB 1841658).
文摘Biological denitrification is a crucial process in the nitrogen biogeochemical cycle,and Thermus has been reported to be a significant heterotrophic denitrifier in terrestrial geothermal environments.However,neither the denitrification potential nor the evolutionary history of denitrification genes in the genus Thermus or phylum Deinococcota is well understood.Here,we performed a comparative analysis of 23 Thermus genomes and identified denitrification genes in 15 Thermus strains.We confirmed that Thermus harbors an incomplete denitrification pathway as none of the strains contain the nosZ gene.Ancestral character state reconstructions and phylogenetic analyses showed that narG,nirS,and norB genes were acquired by the last common ancestor of Thermales and were inherited vertically.In contrast,nirK of Thermales was acquired via two distinct horizontal gene transfers from Proteobacteria to the genus Caldithermus and from an unknown donor to the common ancestor of all known Thermus species except Thermus filiformis.This study expands our understanding of the genomic potential for incomplete denitrification in Thermus,revealing a largely vertical evolutionary history of the denitrification pathway in the Thermaceae,and supporting the important role for Thermus as an important heterotrophic denitrifier in geothermal environments.
基金This work was financially supported by the National 973 Basic Research Program of China （2014CB745100）, National Natural Science Foundation of China （Grant Nos. 21376024 and 21390202）.
文摘MATTt （a thermostable methionine adenosyl- transferase from Thermus thermophilus HB27） was over- expressed in Escherchia coli and purified using Ni-NTA affinity column. The enzymatic activity of MATTt was investigated in a temperature range from 30 ℃ to 90 ℃, showing that MATTt exhibited a high enzymatic activity and good thermostability at 80 ℃. Circular dichroism spectra reveals that MATTt contains high portion of β- sheet structures contributing to the thermostability of MATTt. The kinetic parameter, Km is 4.19 mmoFL and 1.2 mmol/L for ATP and methionine, respectively. MATTt exhibits the highest enzymatic activity at pH 8. Cobalt （Co^2＋） and zinc ion （Zn^2＋） enhances remarkably the activity of MATTt compared to the magnesium ion （Mg^2＋）. All these results indicated that the thermostable MATTt has great potential for industry applications.
