Long Term Effects of Chernobyl Contamination on DNA Repair Function and Plant Resistance to Different Biotic and Abiotic Stress Factors

Thirty years after the Chernobyl explosion we still lack information regarding the genetic effects of radionuclide contamination on the plant population. For example, are plants adapting to the low dose of chronic ionising irradiation and showing improved resistance to radiation damage? Are they coping with changing/increased pathogenicity of fungi and viruses in the Chernobyl exclusion (ChE) zone? Are plant populations rapidly accumulating mutational load and should we expect rapid micro-evolutionary changes in plants in the Chernobyl area? This review will try to summarise the current knowledge on these aspects of plant genetics and ecology and draw conclusions on the importance of further studies in the area around Chernobyl

The Achene Mucilage Hydrated in Desert Dew Assists Seed Cells in Maintaining DNA Integrity: Adaptive Strategy of Desert Plant Artemisia sphaerocephala

Despite proposed ecological importance of mucilage in seed dispersal, germination and seedling establishment, little is known about the role of mucilage in seed pre-germination processes. Here we investigated the role of mucilage in assisting achene cells to repair DNA damage during dew deposition in the desert. Artemisia sphaerocephala achenes were first treated γ-irradiation to induce DNA damage, and then they were repaired in situ in the desert dew. Dew deposition duration can be as long as 421 min in early mornings. Intact achenes absorbed more water than demucilaged achenes during dew deposition and also carried water for longer time following sunrise. After 4-d dew treatment, DNA damage of irradiated intact and demucilaged achenes was reduced to 24.38% and 46.84%, respectively. The irradiated intact achenes exhibited much higher DNA repair ratio than irradiated demucilaged achenes. Irradiated intact achenes showed an improved germination and decreased nonviable achenes after dew treatment, and significant differences in viability between the two types of achenes were detected after 1020 min of dew treatment. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding DNA repair of achene cells in genomic-stressful habitats

ARG098, a novel anti-human Fas antibody, suppresses synovial hyperplasia and prevents cartilage destruction in a severe combined immunodeficient-HuRAg mouse model

<p>Abstract</p> <p>Background</p> <p>The anti-human Fas/APO-1/CD95 (Fas) mouse/human chimeric monoclonal IgM antibody ARG098 (ARG098) targets the human Fas molecule. The cytotoxic effects of ARG098 on cells isolated from RA patients, on normal cells <it>in vitro</it>, and on RA synovial tissue and cartilage <it>in vivo </it>using implanted rheumatoid tissues in an SCID mouse model (SCID-HuRAg) were investigated to examine the potential of ARG098 as a therapy for RA.</p> <p>Methods</p> <p>ARG098 binding to each cell was analyzed by cytometry. The effects of ARG098 on several cells were assessed by a cell viability assay <it>in vitro</it>. Effects on the RA synovium, lymphocytes, and cartilage were assessed <it>in vivo </it>using the SCID-HuRAg mouse model.</p> <p>Results</p> <p>ARG098 bound to cell surface Fas molecules, and induced apoptosis in Fas-expressing RA synoviocytes and infiltrating lymphocytes in the RA synovium in a dose-dependent manner. However, ARG098 did not affect the cell viability of peripheral blood mononuclear cells of RA patients or normal chondrocytes. ARG098 also induced apoptosis in RA synoviocytes and infiltrating lymphocytes in the RA synovium <it>in vivo</it>. The destruction of cartilage due to synovial invasion was inhibited by ARG098 injection in the modified SCID-HuRAg mouse model.</p> <p>Conclusions</p> <p>ARG098 treatment suppressed RA synovial hyperplasia through the induction of apoptosis and prevented cartilage destruction <it>in vivo</it>. These results suggest that ARG098 might become a new therapy for RA.</p

Anhydrobiosis-Associated Nuclear DNA Damage and Repair in the Sleeping Chironomid: Linkage with Radioresistance

Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae had restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated larvae after anhydrobiosis were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He). In contrast, low-LET radiation (gamma-rays) of the same dose caused less initial damage to the larvae, and DNA was completely repaired within within 24 h. The expression of genes encoding the DNA repair enzymes occurred upon entering anhydrobiosis and exposure to high- and low-LET radiations, indicative of DNA damage that includes double-strand breaks and their subsequent repair. The expression of antioxidant enzymes-coding genes was also elevated in the anhydrobiotic and the gamma-ray-irradiated larvae that probably functions to reduce the negative effect of reactive oxygen species upon exposure to these stresses. Indeed the mature antioxidant proteins accumulated in the dry larvae and the total activity of antioxidants increased by a 3–4 fold in association with anhydrobiosis. We conclude that one of the factors explaining the relationship between radioresistance and the ability to undergo anhydrobiosis in the sleeping chironomid could be an adaptation to desiccation-inflicted nuclear DNA damage. There were also similarities in the molecular response of the larvae to damage caused by desiccation and ionizing radiation

DNA Instability in premature aging

DNA damage accumulates with increased chronological age and may contribute to both cell senescence and cancer. However, the importance and role(s) of DNA damage in promoting ageing is difficult to analyze experimentally at the molecular level since ageing results from a complex interplay of genetic and environmental factors. Premature human ageing syndromes offer a route to determining the molecular basis of at least some of the changes in DNA associated with normal ageing, as they are caused by mutation of individual genes whose protein products can be characterized in vitro. Furthermore, experimental manipulation of DNA stability may permit analysis of the contribution of DNA damage to the ageing process. Here, we assess the types of DNA instability observed in premature human ageing, particularly progeroid Hutchison Guilford Progeria and Werner's syndrome, and experimental models of these. The role for RecQ helicases and cognate exonucleases in maintaining DNA stability and preventing premature ageing is discussed in the context of studies in vitro and in model organisms. We conclude that it is by combining studies in various experimental systems that the true in vivo activities of these critical proteins can be elucidated. © 2010 Nova Science Publishers, Inc. All rights reserved

DNA Instability in premature aging

DNA damage accumulates with increased chronological age and may contribute to both cell senescence and cancer. However, the importance and role(s) of DNA damage in promoting ageing is difficult to analyze experimentally at the molecular level since ageing results from a complex interplay of genetic and environmental factors. Premature human ageing syndromes offer a route to determining the molecular basis of at least some of the changes in DNA associated with normal ageing, as they are caused by mutation of individual genes whose protein products can be characterized in vitro. Furthermore, experimental manipulation of DNA stability may permit analysis of the contribution of DNA damage to the ageing process. Here, we assess the types of DNA instability observed in premature human ageing, particularly progeroid Hutchison Guilford Progeria and Werner's syndrome, and experimental models of these. The role for RecQ helicases and cognate exonucleases in maintaining DNA stability and preventing premature ageing is discussed in the context of studies in vitro and in model organisms. We conclude that it is by combining studies in various experimental systems that the true in vivo activities of these critical proteins can be elucidated. © 2010 Nova Science Publishers, Inc. All rights reserved

Telomeres and seed banks

Нами показано, что при продолжительном хранении семян, во время которого жизнеспобность семян снижается от 98 до 0 %, происходит прогрессивная потеря теломерных последовательностей из высокомолекулярной ДНК и их накопление в низкомолекулярной фракции. Распределение теломер по ДНК в целом соответствует стандартным профилям деградации ДНК у семян, хранящихся в сухом виде; при этом также наблюдается общая потеря теломер из ДНК как следствие такого хранения. Существует необходимость в подборе подходящего маркера «качества семян», который можно легко отслеживать в течение хранения. Анализируя возможность применения наших результатов, мы убеждены, что есть значительный потенциал для использования теломерных последовательностей как маркера старения семян, хранящихся в Банках семян

Nucleotide and amino acid sequences of a coat protein of an Ukrainian isolate of Potato virus Y: comparison with homologous sequences of other isolates and phylogenetic analysis

Aim. Identification of the widespread Ukrainian isolate(s) of PVY (Potato virus Y) in different potato cultivars and subsequent phylogenetic analysis of detected PVY isolates based on NA and AA sequences of coat protein. Methods. ELISA, RT-PCR, DNA sequencing and phylogenetic analysis. Results. PVY has been identified serologically in potato cultivars of Ukrainian selection. In this work we have optimized a method for total RNA extraction from potato samples and offered a sensitive and specific PCR-based test system of own design for diagnostics of the Ukrainian PVY isolates. Part of the CP gene of the Ukrainian PVY isolate has been sequenced and analyzed phylogenetically. It is demonstrated that the Ukrainian isolate of Potato virus Y (CP gene) has a higher percentage of homology with the recombinant isolates (strains) of this pathogen (approx. 98.8– 99.8 % of homology for both nucleotide and translated amino acid sequences of the CP gene). The Ukrainian isolate of PVY is positioned in the separate cluster together with the isolates found in Syria, Japan and Iran; these isolates possibly have common origin. The Ukrainian PVY isolate is confirmed to be recombinant. Conclusions. This work underlines the need and provides the means for accurate monitoring of Potato virus Y in the agroecosystems of Ukraine. Most importantly, the phylogenetic analysis demonstrated the recombinant nature of this PVY isolate which has been attributed to the strain group O, subclade N:O