It has been proposed that oxidative stress, elicited by high levels of reactive oxygen species, accelerates telomere shortening by erosion of telomeric DNA repeats. While most eukaryotes counteract telomere shortening by telomerase-driven addition of these repeats, telomeric loss in Drosophila is compensated by retrotransposition of the telomeric retroelements HeT-A, TART and TAHRE to chromosome ends. In this study we tested the effect of chronic exposure of flies to non-/sub-lethal doses of paraquat, which is a redox cycling compound widely used to induce oxidative stress in various experimental paradigms including telomere length analyses. Indeed, chronic paraquat exposure for five generations resulted in elevated transcriptional activity of both telomeric and non-telomeric transposable elements, and extended telomeric length in the tested fly lines. We propose that low oxidative stress leads to increased telomere length within Drosophila populations. For a mechanistic understanding of the observed phenomenon we discuss two scenarios: adaption, acting through a direct stimulation of telomere extension, or positive selection favoring individuals with longer telomeres within the population.

• MeSH
• Drosophila melanogaster účinky léků   genetika   MeSH
• genetická transkripce účinky léků   MeSH
• homeostáza telomer účinky léků   MeSH
• hormeze * MeSH
• paraquat farmakologie   MeSH
• reaktivní formy kyslíku farmakologie   MeSH
• retroelementy účinky léků   MeSH
• telomery účinky léků   fyziologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zkracování telomer účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Despite a high toxicity, paraquat is one of the most widely used herbicides in the world. Our study evaluated the effect of paraquat exposure on antioxidant response and locomotion activity in Drosophila melanogaster. We examined the enzymatic activity of superoxide dismutase (SOD) and catalase, and the transcript levels of both enzymes. Flies were exposed to a wide range of paraquat concentrations (0.25 μM to 25 mM) for 12 h. SOD, at both transcript and enzymatic levels, revealed a biphasic dose-response curve with the peak at 2.5 μM paraquat. A similar dose-response curve was observed at transcript levels of catalase. Males revealed higher susceptibility to paraquat exposure, displaying higher lethality, increased levels of SOD activity, and increased peroxide levels than in females. We found that the exposure of females to 2.5 μM paraquat leads to an increase in locomotion activity. Because susceptibility to paraquat was enhanced by mating, the study supports the hypothesis of elevation of stress sensitivity as a physiological cost of reproduction.

• MeSH
• antioxidancia metabolismus   MeSH
• chování zvířat účinky léků   MeSH
• Drosophila melanogaster účinky léků   metabolismus   MeSH
• herbicidy toxicita   MeSH
• katalasa metabolismus   MeSH
• oxidace-redukce MeSH
• paraquat toxicita   MeSH
• peroxidy metabolismus   MeSH
• rozmnožování účinky léků   MeSH
• sexuální faktory MeSH
• superoxiddismutasa metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH