Kawa skraca życie, alkohol je przedłuża

In a new yeast study, researchers from Tel Aviv University and Columbia University have found that caffeine shortens and alcohol lengthens telomeres – the end points of chromosomal DNA, implicated in aging and cancer.

Telomeres, made of DNA and proteins, mark the ends of the strands of DNA in our chromosomes. They are essential to ensuring that the DNA strands are repaired and copied correctly. Every time a cell duplicates, the chromosomes are copied into the new cell with slightly shorter telomeres. Eventually, the telomeres become too short, and the cell dies. Only fetal and cancer cells have mechanisms to avoid this fate – they go on reproducing forever.

Prof Martin Kupiec of Tel Aviv University with colleagues set out to expand on a 2004 study by Nobel Prize-winning molecular biologist Prof Elizabeth Blackburn, which suggested that emotional stress causes the shortening of the telomeres characteristic of aging, presumably by generating free radicals in the cells. They grew yeast cells in conditions that generate free radicals to test the effect on telomere length.

They then went on to expose the yeast cells to 12 other environmental stressors. Most of the stressors – from temperature and pH changes to various drugs and chemicals – had no effect on telomere length. But a low concentration of caffeine, similar to the amount found in a shot of espresso, shortened telomeres, and exposure to a 5-to-7 percent ethanol solution lengthened telomeres.

To understand these changes, Prof Kupiec’s team scanned 6,000 strains of the yeast, each with a different gene deactivated.

They then conducted genetic tests on the strains with the longest and shortest telomeres, revealing that two genes, Rap1 and Rif1, are the main players mediating environmental stressors and telomere length.

“In total, some 400 genes interact to maintain telomere length, underscoring the importance of this gene network in maintaining the stability of the genome. Strikingly, most of these yeast genes are also present in the human genome,” said Prof Kupiec, who is the senior author of the study published in the journal PLoS Genetics.

“This is the first time anyone has analyzed a complex system in which all of the genes affecting it are known. It turns out that telomere length is something that’s very exact, which suggests that precision is critical and should be protected from environmental effects.”

http://www.sci-news.com/genetics/science-caffeine-alcohol-genome-01605.html

 

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