| 1. |
- Adamowicz-Skrzypkowska, Aleksandra, et al.
(författare)
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Joint inhibition of mitochondrial complex IV and alternative oxidase by genetic or chemical means represses chloroplast transcription in Arabidopsis
- 2020
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Ingår i: Philosophical Transactions of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 375:1801
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the functional state of mitochondria have profound effects on other cellular compartments. Genome-wide expression analysis of Arabidopsis rps10 mutants with an RNAi-silenced expression of mitoribosomal S10 protein has revealed extensive transcriptional reprogramming. A meta-analysis comparing expression datasets of 25 mitochondrial perturbations showed a high similarity of the aox1a:rpoTmp mutant, which is defective in the alternative oxidase (AOX1a) and dual-targeted mitochondrial and plastid RNA polymerase (RPOTmp), to rps10. Both rps10 and aox1a:rpoTmp showed a significantly decreased electron flux through both the cytochrome and the alternative respiratory pathways, and a markedly decreased the expression of nuclear-encoded components of the chloroplast transcription machinery. In line with this, a decreased level of plastid transcripts was observed in rps10 and aox1a: rpoTmp, which was reflected in a reduced rate of chloroplast transcription. Chemical treatment of wild-type seedlings with respiratory inhibitors showed that only simultaneous and direct inhibition of complex IV and AOX activity decreased the level of plastid transcripts. Taken together, both chemical and genetic studies show that the limitation of the activity of two mitochondrial terminal oxidases, complex IV and AOX, negatively impacts chloroplast transcription. Salicylic acid and oxygen are discussed as putative mediators of the signalling pathway between mitochondria, nucleus and chloroplasts. This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’.
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| 2. |
- Brzozowska, Beata, et al.
(författare)
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Freeware tool for analysing numbers and sizes of cell colonies
- 2019
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 58:1, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- The clonogenic cell survival assay is a basic method to study the cytotoxic effect of radiation and chemical toxins. In large experimental setups, counting of colonies by eye is tiresome and prone to bias. Moreover, it is often interesting to quantify the size of individual colonies. Such analyses are largely facilitated by computerised image analysis systems. Although a number of such systems exist, they all focus on enumerating colonies and not on analysing the colony size. We have developed a new software package for both counting colonies and plotting their size distributions. The software called count and Plot HIstograms of Colony Size(countPHICS) consists of two parts: (1) a macro written for ImageJ which analyses computerised images of cell culture dishes or 6-well plates, counts colonies, estimates their size and saves the results in a text file; (2) a program written with QT Creator which reads the text file, plots histograms of colony size distribution and fits the best function. The full program is freely available at: http://www.fuw.edu.pl/similar to bbrzozow/FizMed/countPHICS.html. In conclusion, our new publically available software will facilitate colony counting and provide additional information on the colony growth rate, which is relevant especially for radiosensitisation studies.
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| 3. |
- Czub, Joanna, et al.
(författare)
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Biological effects of mixed-ion beams. Part 1 : Effect of irradiation of the CHO-K1 cells with a mixed-ion beam containing the carbon and oxygen ions
- 2018
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 139, s. 304-309
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Tidskriftsartikel (refereegranskat)abstract
- Carbon and oxygen ions were accelerated simultaneously to estimate the effect of irradiation of living cells with the two different ions. This mixed ion beam was used to irradiate the CHO-K1 cells, and a survival test was performed. The type of the effect of the mixed ion beam on the cells was determined with the isobologram method, whereby survival curves for irradiations with individual ion beams were also used. An additive effect of irradiation with the two ions was found.
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| 4. |
- Czub, Joanna, et al.
(författare)
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Biological effects of mixed-ion beams. Part 2 : The relative biological effectiveness of CHO-K1 cells irradiated by mixed- and single-ion beams
- 2019
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 150, s. 192-198
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Tidskriftsartikel (refereegranskat)abstract
- The relative biological effectiveness (RBE) values were determined for single- and mixed-ion beams containing carbon and oxygen ions. The CHO-K1 cells were irradiated with beams with the linear energy transfer (LET) values of 236-300 and 461-470 keV/mu m for C-12 and O-16 ions, respectively. The RBE was estimated as a function of dose, survival fraction (SF) and LET. The SF was not affected by varying contributions of the constituent ions to the total mixed dose. The RBE has the same value for single-ion exposures with ions with LET 300 (C-12) and 470 keV/mu m (O-16).
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| 5. |
- Płódowska, Magdalena, et al.
(författare)
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Small is beautiful : low activity alpha and gamma sources for small-scale radiation protection research experiments
- 2021
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 97:4, s. 541-552
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Uncertainties regarding the magnitude of health effects following exposure to low dosesof ionizing radiation remain a matter of concern both for professionals and for the public. There isconsensus within the international radiation research community that more research is requiredon biological effects of radiation doses below 100 mGy applied at low dose rates. Moreover, thereis a demand for increasing education and training of future radiation researchers and regulators.Research, education and training is primarily carried out at universities but university-based radiationresearch is often hampered by limited access to radiation sources. The aim of the presentreport is to describe small and cost-effective low activity gamma and alpha sources that can easilybe installed and used in university laboratories.Methods and results: A gamma radiation source was made from an euxenite-(Y) rock(Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6) that was found in an abandoned mine in Sweden. It allows exposingcells grown in culture dishes to radiation at a dose rate of 50 μGy/h and lower. Three alpha sourceswere custom-made and yield a dose rate of 1 mGy/h each. The construction, dosimetry andcellular effects of the sources are described.Conclusions: We hope that the report will stimulate research and training activities in the lowdose field by facilitating access to radiation sources.
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