Choice of coffee or beer can affect your DNA

December 6, 2013

DNAJerusalem, Dec 6: Your choice of coffee or beer can not only affect your mood, but also influence a part of DNA linked to ageing and cancer, a new study claims.

Working with a kind of yeast that shares many important genetic similarities with humans, the researchers from the Tel Aviv University found that caffeine shortens and alcohol lengthens telomeres - the end points of chromosomal DNA, implicated in ageing and cancer.

"For the first time we've identified a few environmental factors that alter telomere length, and we've shown how they do it," said Professor Martin Kupiec.

"What we learned may one day contribute to the prevention and treatment of human diseases," said Kupiec. Telomeres, made of DNA and proteins, mark the ends of the strands of DNA in our chromosomes and are essential to ensuring that 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 foetal and cancer cells have mechanisms to avoid this fate.

The researchers grew yeast cells in conditions that generate free radicals to test the effect on telomere length.

They were surprised to find that the length did not change. They 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 per cent ethanol solution lengthened telomeres.

To understand these changes, researchers 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, researchers note, 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.

"This is the first time anyone has analysed a complex system in which all of the genes affecting it are known," said Kupiec. The study was published in the journal PLOS Genetics.

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Agencies
May 25,2020

Singapore, May 25: COVID-19 patients are no longer infectious after 11 days of getting sick even though some may still test positive, according to a new study by infectious disease experts in Singapore.

A positive test "does not equate to infectiousness or viable virus," a joint research paper by Singapore's National Centre for Infectious Diseases and the Academy of Medicine, Singapore said. The virus "could not be isolated or cultured after day 11 of illness."

The paper was based on a study of 73 patents in the city-state.

The latest findings may have implications on the country's patient discharge policy. The discharge criteria is currently based on negative test results rather than infectiousness.

Singapore's strategy on managing COVID-19 patients is guided by the latest local and international clinical scientific evidence, and the Ministry of Health will evaluate if the latest evidence can be incorporated into its patient clinical management plan, according to a report by the Straits Times.

So far, 13,882, or about 45% of the total 31,068 Covid-19 patients in Singapore have been discharged from hospitals and community facilities. Singapore reported 642 new Covid-19 cases as of noon on Saturday.

The government has been actively screening pre-school staff as it prepares to reopen pre-schools from June 2. On Friday, two pre-school employees tested positive for the novel coronavirus, bringing the total number of confirmed cases among pre-school staff to seven, according to the Ministry of Health.

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Agencies
April 15,2020

Dear parents, if you want your children to have proper sleep, read this carefully. Joining a growing list of studies that tell parents to shun devices at bed-time, researchers say that children who use devices and decide what time they go to sleep, achieve less sleep and feel more sleepier the following day than their peers.

The study of children in this age-group (aged 11 to 13 years), published in the New Zealand Medical Journal, found most (72 per cent) of the 163 students interviewed by University of Otago researchers achieved recommended guidelines of an average 9 to 11 hours sleep nightly over one week.

"But that also means that almost one in four students did not achieve sleep within these guidelines, which highlights an area for improvement," said study researcher Kate Ford.

However, consistent with previous research in 15 to 17-year-old New Zealanders, the study results show less sleep on the nights where devices are used in the hour before bed.

According to the researchers, students who used devices before going to sleep were also more likely to report that they felt sleepy the following morning. Watching television before bed had no significant effect on sleep length.

There were also some interesting observations over the weekends where students went to bed later but woke later achieving similar sleep length to the school days, the researchers said.

A small group of students (six per cent) who reported less than seven hours of sleep, including a small number reporting not sleeping at all, according to the study,

Therefore, while the average across the week of 72 per cent of students reporting adequate sleep is reassuring, it is far from the goal of every child achieving sleep within the recommended guidelines," Ford said.

Dr Paul Kelly, head of the Sleep Health Service at Canterbury District Health Board, supervised the study and explained that the foundations for good health are based on proper nutrition, regular exercise and good sleep quality.

Sleep quality is often overlooked as a contributory factor to poor health.

"The study findings suggest the need for parental guidance around bedtimings and moderation of the use and availability of electronic devices before bed," Kelly said.

"Respect and protect your sleep, as good daytime functioning is reliant on adequate sleep," Kelly added.

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June 23,2020

The record levels of new daily COVID-19 cases are due to the fact that the pandemic is peaking in a number of big countries at the same time and reflect a change in the virus' global activity, the World Health Organisation said.

At a media briefing on Monday, WHO's emergencies chief Dr Michael Ryan said that the numbers are increasing because the epidemic is developing in a number of populous countries at the same time.

Some countries have attributed their increased caseload to more testing, including India and the US But Ryan dismissed that explanation.

We do not believe this is a testing phenomenon, he said, noting that numerous countries have also noted marked increases in hospital admissions and deaths neither of which cannot be explained by increased testing.

There definitely is a shift in that the virus is now very well established, Ryan said. The epidemic is now peaking or moving towards a peak in a number of large countries.

He added the situation was definitely accelerating in a number of countries, including the US and others in South Asia, the Middle East and Africa.

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