Effect of heat shock on the mutagenicity of mutagens and carcinogens in <i>Euglena gracilis</i>

Chreno, O.; Krajčovič, Juraj; Ebringer, L.; Polónyi, J

doi:10.1002/tcm.1770080305

Cited by 7 publications

(4 citation statements)

References 20 publications

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“…These findings are also remarkable in that previously evaluated antibiotics eliminated E. gracilis chloroplasts only from growing cells (6)(7)(8)(9). In contrast, mutagens and carcinogens eliminated chloroplasts from either growing or nongrowing cells (3,8,9). We recently identified differences between DNA gyrase inhibitors and classical mutagens in their action on E. gracilis chloroplasts.…”

Section: Discussionmentioning

confidence: 87%

“…Exposure to coumermycin A1 results in growth of not only green and white colonies but also mosaic or ringlike colonies. Such mixed colonies are only sometimes induced by exposure to other DNA gyrase antagonists but are commonly seen after exposure to mutagens and carcinogens (3).…”

Section: Discussionmentioning

confidence: 99%

“…These organelles are semiautonomous (with their own DNA and protein synthesis apparatus) and appear to be of eubacterial origin (9,10,13,21). We previously demonstrated that chloroplasts of the flagellate Euglena gracilis are susceptible to antibacterial agents and other biologically active compounds (3,(6)(7)(8)(9)(10). In contrast to the higher plants, chloroplasts in E. gracilis are not essential, thus placing this unicellular eucaryotic microorganism on the boundary between the plant and animal kingdoms.…”

mentioning

confidence: 99%

“…The antichloroplastic activities of various drugs on E. gracilis are macroscopically manifested by the permanent loss of the ability to form green colonies, with cells changing from autotrophy to heterotrophy and becoming white (bleaching). As determined by electron microscopic evaluation, bleaching is associated with degradation and loss of chloroplasts (3,24; J. Polonyi, L. Ebringer, J. Krajcovic, and K. Kapeller, Z. Mikroskop.-Anat. Forsch., in press).…”

mentioning

confidence: 99%

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Quinolones and coumarins eliminate chloroplasts from Euglena gracilis

Krajčovič

Ebringer

Polónyi

1989

Antimicrob Agents Chemother

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Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Quinolones and coumarins eliminate chloroplasts from Euglena gracilis

Krajčovič

Ebringer

Polónyi

1989

Antimicrob Agents Chemother

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Interaction of drugs with extranuclear genetic elements and its consequences

Ebringer¹

1990

Teratog Carcinog Mutagen

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Bacterial ancestry of mitochondria and plastids is now generally accepted. Both organelles contain their own DNA and transcription-translation apparatus of a prokaryotic type. Due to this fact these systems carry bacteria-like properties. Thus organellar DNA and ribosomes are essentially different from nuclear DNA and cytoplasmic ribosomes in physical as well as in functional respects. Due to the bacterial character of both types of organelles they are susceptible to various antibacterial chemicals. Inhibitors of bacterial protein synthesis inhibit mitochondrial (plastidial) biogenesis. Therefore the cellular content of mitochondria (plastids)-made proteins decreases during cytoplasmic turnover or cell division in the presence of these drugs. Such drug activity consequently leads to a reduced capacity for oxidative phosphorylation or photosynthesis. Organellar genomes are less stable and more sensitive to mutagenesis as compared to nuclear genome. It means also that genotoxic agents induce various disorders of mitochondrial (plastidial) functions. Impairments in the respiratory chain are associated with structural as well as functional abnormalities of mitochondria. These are clinically expressed mostly in tissues with a high demand for ATP: brain, heart, skeletal muscle, and retina. On the other hand, some antibacterial inhibitors of mitochondrial biogenesis (e.g., tetracyclines) inhibit selectively tumor cell proliferation. Therefore they may be considered for use in anticancer therapy. The article summarizes the response of mitochondria and plastids in various organisms to drugs and environmental xenobiotics. Various model organisms suitable for detection of xenobiotic effect on mitochondria (plastids) are presented as well as the possible consequences of such interaction.

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