Progress in ionizing radiation resistance modification of polymer materials

With the wide application of polymer materials, much attention has been paid to the modification methods of polymer materials with high-energy radiation resistance to satisfy special environment, such as nuclear industry, space technology, medical equipmen. In this review, progress in ionizing radiation resistance modification of polymer materials is introduced in depth and different modification methods are compared. Finally, future perspectives of this field are discussed.

Identification of Fungi Resistant to 137Cs Gamma Radiation From an Artwork by Candido Portinari

Gamma radiation is a safe and effective technique for the treatment of art collections being used with high efficiency in reducing microbial loads being obtained by the emission of a radioactive isotope, such as Cesium 137. Portinari's work, from the collection of the National Museum (Brazil), was analyzed and the fungi contained therein were collected, isolated, and further treated with gamma radiation for decontamination. Radiation doses used were 16, 19 and 22 kGy. Results indicated 11 genera and 17 species isolated. Penicillium and Cladosporium were isolated in air, artwork and its support - emphasizing the predominance they assume in the contamination of works of art under favorable conditions, such as museums. The genera Penicillium, Cladosporium, Nigrospora and Curvularia showed high resistances (16 kGy). The most resistant was Cladosporium, which showed no growth under 22 kGy. As there are some differences in ionizing radiation resistance among fungi from the same order or species, the results here outlined indicates that the rates of DNA damage and repair were critical, depending on chronic or acute dose irradiated. The biochemical mechanism acting on fungal cells under irradiation was basically the inactivation of specific enzymes and, probably, DNA damage, particularly stimulating double-strand breaks.

DetR DB: A Database of Ionizing Radiation Resistance Determinants

Nuclear pollution is an urgent environmental issue and is a consequence of rapid industrialization and nuclear accidents in the past. Remediation of nuclear polluted sites using microbial vital activity (bioremediation) is a promising approach to recover contaminated areas in an environmentally friendly and cost-saving way. At the same time, the number of known bacterial and archaeal species able to withstand extremely high doses of ionizing radiation (IR) is steadily growing every year, together with growing knowledge about mechanisms of radioresistance that opens up opportunities for developing new biotechnological solutions. However, these data are often not systemized, and can be difficult to access. Here, we present the Determinants of Radioresistance Database, or DetR DB, gathering a comprehensive catalog of radioresistant microbes and their molecular and genetic determinants of enhanced IR tolerance. The database provides search tools, including taxonomy, common gene name, and BLAST. DetR DB will be a useful tool for the research community by facilitating the extraction of the necessary information to help further analysis of radiation-resistant mechanisms.

DetR DB: A Database of Ionizing Radiation Resistance Determinants

Nuclear pollution is an urgent environmental issue as a consequence of rapid industrialization and nuclear accidents in the past. Remediation of nuclear polluted sites using microbial vital activity (bioremediation) is a promising approach to recover contaminated areas in an environmentally friendly and cost-saving way. At the same time, the number of known bacterial and archaeal species able to withstand extremely high doses of ionizing radiation is steadily growing every year, together with growing knowledge about mechanisms of radioresistance. This opens up new opportunities for developing new biotechnological solutions. However, these data are often not systemized and it can be difficult to access. Here, we present the Determinants of Radioresistance Database, or DetR DB (http://extremebiolab.com/detr-db/), gathering a comprehensive catalog of radioresistant microbes and their molecular and genetic determinants of enhanced ionizing radiation tolerance. The database provides search tools including taxonomy, common gene name, and BLAST. DetR DB will be a useful tool for research community by facilitating the extraction of the necessary information to help further analysis of radiation-resistant mechanisms.

A hyperactive variant of theEscherichia colianaerobic transcription factor FNR enhances ionizing radiation resistance

We have previously generated four replicate populations of ionizing radiation (IR)- resistantEscherichia colithough directed evolution. Sequencing of isolates from these populations revealed that mutations affecting DNA repair (through DNA double-strand break repair and replication restart), ROS amelioration, and cell wall metabolism were prominent. Three mutations involved in DNA repair explained the IR resistance phenotype in one population, and similar DNA repair mutations were prominent in two others. The remaining population, IR-3-20, had no mutations in the key DNA repair proteins, suggesting that it had taken a different evolutionary path to IR resistance. Here, we present evidence that a variant of the anaerobic metabolism transcription factor FNR isolated from population IR-3-20 can play a role in IR resistance. An FNR variant is unique to IR-3-20 and suggests a role for altered global metabolism through the FNR regulon as a means for experimentally-evolved IR resistance.