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Due to its potential applications in cultivated plants, ionizing radiation (IR) and its effect on organisms is increasingly studied. Here we measured the effects of ionizing radiation on Eruca sativa by analyzing plants from irradiated seeds (1 and 10 Gy) grown in hydroponics. We measured several morpho-physiological traits and genotoxicity. Radiation stress induced a noticeable variability of the morpho-physiological traits highlighting decreased plant vigor. Shoot length and leaf number were significantly higher in 1 Gy-treated samples, whereas root length was significantly higher in 10 Gy treated plants. Stomata number significantly increased with IR dose, whereas both pigment and Rubisco content decreased under radiation stress. Phenol content significantly increased in 1 Gy treated samples, otherwise from total antioxidants, which were not different from control. Most results could find a feasible explanation in a hormesis-like pattern and in a decreased plant vigor under radiation stress. IR induced genotoxic damage, evaluated by ISSR markers, in 15 day old leaves; specifically, a severe decrease in the genome template stability was observed. However, a partial recovery occurred after 2 weeks, especially under the lowest dose ( i.e ., 1 Gy), suggesting that DNA damage detection and repair mechanisms are active. Pigment content and genotoxic damage may serve as proxies for evaluating plant responses to IR stress, since they show univocal dose-dependent trends. The use of more checkpoints for analyses and more doses over a wider range, as well as the focus on different metabolites, could help elucidate plant response in terms of morpho-physiological changes., Competing Interests: Fiore Capozzi and Valeria Spagnuolo are Academic Editors for PeerJ., (© 2023 Sorrentino et al.)

Among different radiotherapy techniques, proton irradiation is an established and effective method for treatment of several types of cancer, because less healthy tissue is exposed with respect to conventional radiotherapy by photons/electrons. Recently, proton therapy has been proposed for the treatment of breast cancer. In vitro studies of proton irradiated normal human breast cells can provide information about cellular radioresponse, particularly as far as healthy tissue is concerned. In this paper, a study of the effects at different time points, following proton irradiation at different doses, of human normal MCF10A breast cells is performed by Raman spectroscopy. The aim of this investigation is to detect the unwanted effects of proton treatment and to investigate the possibility of monitoring them and of making an assessment of the cellular sensitivity by means of such a technique. The obtained results seem to indicate a rather significant sensitivity of MCF10A cells to proton irradiation. In fact, even at doses as low as 0.5 Gy, biological effects are clearly detectable in Raman spectra. In particular, ratiometric analysis of the Raman spectra measured from the nucleoplasm compartment showed that DNA/RNA damage increases with time, suggesting that most cells are unable to repair DNA/RNA broken bonds. The results obtained by the Raman spectroscopy analysis exhibit a similar trend with regard to dose to those obtained by commonly used radiobiological assays (i.e. MTT, clonogenic assay, senescence, apoptosis and necrosis). The results of this study strongly suggest the possibility that the Raman technique can be used to identify molecular markers predicting radiation response.

mRNA splicing and export plays a key role in the regulation of gene expression, with recent evidence suggesting an additional layer of regulation of gene expression and cellular function through the selective splicing and export of genes within specific pathways. Here we describe a role for the RNA processing factors THRAP3 and BCLAF1 in the regulation of the cellular DNA damage response (DDR) pathway, a key pathway involved in the maintenance of genomic stability and the prevention of oncogenic transformation. We show that loss of THRAP3 and/or BCLAF1 leads to sensitivity to DNA damaging agents, defective DNA repair and genomic instability. Additionally, we demonstrate that this phenotype can be at least partially explained by the role of THRAP3 and BCLAF1 in the selective mRNA splicing and export of transcripts encoding key DDR proteins, including the ATM kinase. Moreover, we show that cancer associated mutations within THRAP3 result in deregulated processing of THRAP3/BCLAF1-regulated transcripts and consequently defective DNA repair. Taken together, these results suggest that THRAP3 and BCLAF1 mutant tumors may be promising targets for DNA damaging chemotherapy., (© The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.)

The polykaryon-forming unit (PFU) cell survival assay is based on the postirradiation flow cytometric analysis of the DNA content accumulated in high-ploidy cells (polykaryons) induced by the cytokinesis inhibitor cytochalasin B and can provide a meaningful measure of cell radiosensitivity. In this assay, cell survival is defined as the ability to form a polykaryon of a given ploidy after irradiation. The slope of the polykaryon dose response has been shown to be highly correlated with the initial slope of the clonogenic survival curves after gamma irradiation, which implies a common subset of lethal lesions. We reported previously on an apoptotic mode of cell death in the polykaryon system and on the heritability of small variations in polykaryon radioresponse. We now show that exposure of PFUs to a given dose of alpha particles results in a greater reduction in the proportion of cells able to reach at least 16C when compared to the same dose of low-LET radiation. This reduction is less than that observed in the low-dose (alpha term) region of the clonogenic curve. On the basis of published LET-dependent spectra of radiation-induced DNA damage, we suggest that this behavior reflects a differential expression of lethal damage that can be probed by varying the LET of the radiation and that base damages contributing additional complexity to clustered DNA lesions may be more deleterious in PFUs than in clonogens.

In the polykaryon-forming unit (PFU) assay, which defines cell survival as the ability to form a cytochalasin-induced polykaryon of predetermined ploidy, the mode of PFU deletion is not known. Incubation of L5178Y-S PFU in cytochalasin resulted in polyploidy (> or =32C) and most polykaryons (>75%) ultimately underwent apoptosis, detected using chromatin condensation and externalised phosphatidylserine. However, large polykaryons carrying terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL)-labelled DNA strand breaks were not observed, presumably due to rapid loss of DNA. Gamma irradiation of PFU prior to cytochalasin exposure caused a reduction in the frequency of highly polyploid cells (>16C), consistent with either a supra-induction of apoptosis or a reduction in the ability of PFU to reach high ploidies. We conclude that L5178Y-S PFU are deleted by apoptosis., (Copyright 2000 Academic Press.)

The aim was to evaluate the effect of modelled microgravity on radiation-induced chromosome aberrations (CAs). G0 peripheral blood lymphocytes were exposed to 60 MeV protons or 250?kVp X-rays in the dose range 0?–?6?Gy, and allowed to repair DNA damage for 24?h under either normal gravity or microgravity modelled by the NASA-designed rotating-wall bioreactor. Cells were then stimulated to proliferate by phytohaemagglutinin (PHA) under normal gravity conditions and prematurely condensed chromosomes were harvested after 48?h. CAs were scored in chromosomes 1 and 2 by fluorescence in-situ hybridization. Proliferation gravisensitivity was examined by cell growth curves and by morphological evaluation of mitogen-induced activation. Cell replication rounds were monitored by bromodeoxyuridine labelling. Modelled microgravity markedly reduced PHA-mediated lymphocyte blastogenesis and cell growth. However, no significant differences between normal gravity and modelled microgravity were found in the dose?–?response curves for the induction of aberrant cells or total interchromosomal exchange frequency. Rotating-wall bioreactor-based microgravity reproduced space-related alterations of mitogen stimulation in human lymphocytes but did not affect the yield of CAs induced by low- linear energy transfer radiation. [ABSTRACT FROM AUTHOR]