Both endogenous processes and exogenous physical and chemical sources generate deoxyribonucleic acid (DNA) damage in the nucleus and organelles of living cells. To prevent deleterious effects, damage is balanced by repair pathways. DNA repair was first documented for the nuclear compartment but evidence was subsequently extended to the organelles. Mitochondria and chloroplasts possess their own repair processes. These share a number of factors with the nucleus but also rely on original mechanisms. Base excision repair remains the best characterized. Repair is organized with the other DNA metabolism pathways in the organelle membrane-associated nucleoids. DNA repair in mitochondria is a regulated, stress-responsive process. Organelle genomes do not encode DNA repair enzymes and translocation of nuclear-encoded repair proteins from the cytosol seems to be a major control mechanism. Finally, changes in the fidelity and efficiency of mitochondrial DNA repair are likely to be involved in DNA damage accumulation, disease and aging. The present review successively addresses these different issues.

Despite constant threat of oxidative damage, sequence drift in mitochondrial and chloroplast DNA usually remains very low in plant species, indicating efficient defense and repair. Whereas the antioxidative defense in the different subcellular compartments is known, the information on DNA repair in plant organelles is still scarce. Focusing on the occurrence of uracil in the DNA, the present work demonstrates that plant mitochondria possess a base excision repair (BER) pathway. In vitro and in organello incision assays of double-stranded oligodeoxyribonucleotides showed that mitochondria isolated from plant cells contain DNA glycosylase activity specific for uracil cleavage. A major proportion of the uracil–DNA glycosylase (UDG) was associated with the membranes, in agreement with the current hypothesis that the DNA is replicated, proofread and repaired in inner membrane-bound nucleoids. Full repair, from uracil excision to thymidine insertion and religation, was obtained in organello following import of a uracil-containing DNA fragment into isolated plant mitochondria. Repair occurred through single nucleotide insertion, which points to short-patch BER. In vivo targeting and in vitro import of GFP fusions showed that the putative UDG encoded by the At3g18 630 locus might be the first enzyme of this mitochondrial pathway in Arabidopsis thaliana.

This study examined an innovative approach to functional finishes of linen-containing fabrics. Modification of surface properties along with creation on new interactive site onto the fabrics surfaces, i.e., —COOH or —NH2 groups, using oxygen-or nitrogen plasma followed by subsequent treatments with selected ionic dyes, certain metal salts, nano-scale metal or metal oxides, quaternary ammonium salt or nominated antibiotics were carried out to obtain linen-based textiles with upgrade UV-protection and/or antibacterial functions. The results detailed in this paper demonstrate that: (i) post-basic dyeing of oxygen plasma-treated substrates with C.I. Basic Red 24 brings about a significant improvement in the UV-protection and antibacterial activity against the G +ve (Staphylococcus aureus) and G —ve (Escherichia coli) bacteria, (ii) post-reactive dyeing of nitrogen plasma-treated substrates with C.I. Reactive violet 5, results in a remarkable improvement in both UV-blocking and antibacterial properties. (iii) the extent of improvement in the above-mentioned properties of the obtained dyeings is determined by the type of substrate, kind and concentration of the ionic dye, (iv) loading of the metal ions onto the preactivated fabric surfaces upgraded their UV-protection valued as well as their antibacterial efficiency, and the extent of enhancement is governed by the kind and concentration of metal salt as well as type of bacteria, (v) loading of nano-scale Ag, TiO2, or ZrO onto the plasma-treated substrates brings about a remarkable improvement in their functional properties, (vi) loading of the used antibiotics or choline chloride onto the plasma-treated substrates gives rise to better antibacterial ability, (vii) both the UV-protection ability and the antibacterial activity of selected samples were retained even after 10 laundering cycles, and (viii) the options described here for attaining linen-containing fabrics with high functional properties are effective, simple and applicable.