To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.col...To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+、 N+( 20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.展开更多
Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to o...Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.展开更多
Objectives:This study used Deinococcus radiodurans,which is extremely resistant to oxidative damage,genotoxic chemicals,high levels of ionising and ultraviolet radiation and drying,and its Vitreoscilla haemoglobin(vgb...Objectives:This study used Deinococcus radiodurans,which is extremely resistant to oxidative damage,genotoxic chemicals,high levels of ionising and ultraviolet radiation and drying,and its Vitreoscilla haemoglobin(vgb)gene-cloned recombinant with the vgb−recombinant strain as a control.In addition to the conditions wherein bacteria have an optimum Cr(Ⅲ)biosorption capacity,the contribution of the vgb gene to the biosorption ability of the bacteria has been investigated by providing the organism with a more oxygenic environment.Methods:Bacteria were produced and metal stock solution was prepared.To determine the Cr(Ⅲ)removal capacities of wild and recombinant D.radiodurans strains,the residual metal concentration in aqueous media at the beginning and after biosorption was determined in Atomic Absorption Spectrophotometer.Some optimal conditions were created for the biosorption conditions to occur.Conclusions:The optimisation tests showed that Cr(Ⅲ)reached the highest biosorption capacity within 15 minutes at a metal concentration of 2,000 ppm,30°C,pH 5.0 and 150 rpm stirring speed in all the three bacteria.The vgb gene had no significant contribution to the biosorption capacity.展开更多
Deinococcus radiodurans (D. radiodurans) is distinguished by the most radioresistant organism ever known, and can tolerate extreme environments such as ionizing radiation, ultraviolet radiation, oxidation, and desicca...Deinococcus radiodurans (D. radiodurans) is distinguished by the most radioresistant organism ever known, and can tolerate extreme environments such as ionizing radiation, ultraviolet radiation, oxidation, and desiccation. D. radiodurans is an important model for studying DNA damage/repair and redox regulation upon high dose ionizing radiation. How D. radiodurans response and repair ROS-induced oxidative damage remains a subject of ongoing investigation. This review provides an overview of the radioresistance characteristics of D. radiodurans. Among them, the DNA damage repair pathway and high-efficiency antioxidant defense system are summarized in detail. Furthermore, a novel model that protects the cell against the ionizing radiation is proposed. This review also discusses the potential application , future challenges and directions in advancing towards D. radiodurans studies.展开更多
基金the National Natural Science Foundation of China! No.196O5005)
文摘To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+、 N+( 20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.
基金This work was supported by the National Nature Science Foundation of China! No.19605005
文摘Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.
基金This study was supported by Inonu University Scientific Research Projects Coordination Unit(project number:2012-192).
文摘Objectives:This study used Deinococcus radiodurans,which is extremely resistant to oxidative damage,genotoxic chemicals,high levels of ionising and ultraviolet radiation and drying,and its Vitreoscilla haemoglobin(vgb)gene-cloned recombinant with the vgb−recombinant strain as a control.In addition to the conditions wherein bacteria have an optimum Cr(Ⅲ)biosorption capacity,the contribution of the vgb gene to the biosorption ability of the bacteria has been investigated by providing the organism with a more oxygenic environment.Methods:Bacteria were produced and metal stock solution was prepared.To determine the Cr(Ⅲ)removal capacities of wild and recombinant D.radiodurans strains,the residual metal concentration in aqueous media at the beginning and after biosorption was determined in Atomic Absorption Spectrophotometer.Some optimal conditions were created for the biosorption conditions to occur.Conclusions:The optimisation tests showed that Cr(Ⅲ)reached the highest biosorption capacity within 15 minutes at a metal concentration of 2,000 ppm,30°C,pH 5.0 and 150 rpm stirring speed in all the three bacteria.The vgb gene had no significant contribution to the biosorption capacity.
基金supported by the National Undergraduate Training Program for Innovation and Entrepreneurship of China(Project number:202010007748).
文摘Deinococcus radiodurans (D. radiodurans) is distinguished by the most radioresistant organism ever known, and can tolerate extreme environments such as ionizing radiation, ultraviolet radiation, oxidation, and desiccation. D. radiodurans is an important model for studying DNA damage/repair and redox regulation upon high dose ionizing radiation. How D. radiodurans response and repair ROS-induced oxidative damage remains a subject of ongoing investigation. This review provides an overview of the radioresistance characteristics of D. radiodurans. Among them, the DNA damage repair pathway and high-efficiency antioxidant defense system are summarized in detail. Furthermore, a novel model that protects the cell against the ionizing radiation is proposed. This review also discusses the potential application , future challenges and directions in advancing towards D. radiodurans studies.
