Publications by authors named "Polina Klimenkova"
Denham Harman's oxidative damage theory identifies superoxide (O) radicals as central agents of aging and radiation injury, with Mn-dependent superoxide dismutase (MnSOD) as the principal O-scavenger. However, in the radiation-resistant nematode Caenorhabditis elegans, the mitochondrial antioxidant enzyme MnSOD is dispensable for longevity, and in the model bacterium Deinococcus radiodurans, it is dispensable for radiation resistance. Many radiation-resistant organisms accumulate small-molecule Mn-antioxidant complexes well-known for their catalytic ability to scavenge O, along with MnSOD, as exemplified by D.
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- Chronic ionizing radiation from sources like nuclear accidents and space exploration threatens human health, but fungi show remarkable resistance to such radiation.
- A study tested 95 fungal isolates for their ability to withstand chronic ionizing radiation, heavy metals, high temperatures, and low pH, giving insights into their resistance mechanisms.
- Results indicated that resistance to chronic ionizing radiation in fungi is primarily linked to their resistance to chromium and elevated temperatures, highlighting fundamental differences in how fungi cope with chronic versus acute radiation exposure.
Highly concentrated radionuclide waste produced during the Cold War era is stored at US Department of Energy (DOE) production sites. This radioactive waste was often highly acidic and mixed with heavy metals, and has been leaking into the environment since the 1950s. Because of the danger and expense of cleanup of such radioactive sites by physicochemical processes, bioremediation methods are being developed for cleanup of contaminated ground and groundwater.
View Article and Find Full Text PDFUnderstanding chronic ionizing radiation (CIR) effects is of utmost importance to protecting human health and the environment. Diverse bacteria and fungi inhabiting extremely radioactive waste and disaster sites (e.g.
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- Current genomic approaches cannot predict ionizing radiation (IR) resistance in cells; instead, electron paramagnetic resonance (EPR) spectroscopy reveals insights into DNA repair efficiency related to gamma radiation exposure.
- IR-resistant cells possess high levels of manganous ions organized in high-symmetry antioxidant complexes, enabling effective double-strand break repair, while IR-sensitive cells have manganese in low-symmetry complexes, indicating poor repair capabilities.
- The research suggests that IR resistance is influenced more by metabolic factors and cellular nutrition than by the presence of specific DNA repair or antioxidant enzymes.
Article Synopsis
- The study focuses on the genome sequencing and characterization of the IR-resistant bacterium KS 0460, which serves as a model to understand the effects of ionizing radiation on living organisms.
- The genome of KS 0460 consists of a 4.019 Mbp sequence with high GC content, featuring 3894 predicted genes, and is mostly organized in circular forms.
- A comparison with other bacteria reveals notable differences in metabolic pathways, including missing enzymes related to purine degradation and distinct genes linked to nitrogen metabolism and IR resistance.