Science news digest – 15th July 2013
In the news this week: mothers’ stress during pregnancy can cause depression in children, factory farms appear to spread MRSA, fracking might cause major earthquakes, and a new type of concrete that absorbs air pollution.
A mother’s stress during pregnancy can cause depression in children
Stress hormones can be passed from mother to unborn child, potentially causing anxiety and depression in later life, according to research from the University of Edinburgh. The study uncovers the part of the placenta responsible for protecting a foetus from stress.
Professor Jonathan Seckl, lead researcher on the work undertaken at the Queen’s Medical Research Institute at the University of Edinburgh, told The Telegraph: “There is an enzyme found in high levels in the placenta and the baby’s brain.
"It seems to be a natural barrier to stress hormones as it deactivates them.
“If you inhibit this barrier then you start to get children being born with low birth weight and who have altered stress responses and depression. This may be what underpins the variation you get from one individual to another.”
The enzyme barrier can be overwhelmed by extreme stress levels, such as during an emotional upheaval, allowing stress hormones to pass into the baby’s brain. Once passed on, the chemicals can alter brain development and have previously been linked to lower intelligence levels and behavioural disorders in children.
According to the Daily Mail, another substance that can damage the enzyme barrier is found in liquorice, a particular problem in Finland, where the sweet is popular among young women. Seckl explained: “When we looked at Finnish women – who tend to eat a lot of liquorice – those who ate a bag a day compared with those who did not tended to have babies born a couple of days earlier. By the age of eight, we saw a two-thirds increase in the rates of attention deficits and anxiety behaviours.”
The researchers believe they have found a molecule that indicates exposure to high levels of stress in the womb, which opens up the possibility of a diagnostic test and possibly even new types of treatment.
Factory farms could be breeding ground for MRSA and similar bacteria
Factory farming methods could be causing an increase in dangerous infections such as MRSA, according to a study published in PLoS One. Workers in factories where animals are kept enclosed in confined spaces were found to have higher levels of Methicillin-resistant Staphylococcus Aureus in their airways, prompting fears that the bacteria is making its way into food.
MRSA usually spreads in hospitals, where it weakens the immune system, causes skin abscesses and can lead to death. Many scientists believe that the rising prevalence of the disease is caused by the liberal use of antibiotics. As the bacteria are frequently exposed to the chemicals, random mutations help a small number to survive, according to Smithsonian Magazine.
In factory farms, animals such as pigs, cows and chickens are bred in such close quarters that any infection spreads quickly. Antibiotics are often administered as a preventative measure, but also because they encourage growth. In these farms, just as in hospitals, bacteria are forced to evolve if they want to survive, effectively creating a breeding ground for drug-resistant diseases.
The study found that MRSA was present in 37 per cent of workers in factory farms, compared to 19 per cent in farms that did not use antibiotics. “This study shows that these livestock-associated strains are present among workers at industrial livestock operations and that these strains are resistant not just to methicillin, but to multiple antibiotics — including antibiotics that are used to treat human infections,” Christopher Heaney, corresponding author of the study, told the New York Times.
None of the workers studied showed signs of an active MRSA infection, and the causal link cannot be confirmed because of potential external factors, but the study raises questions about intensive farming that might not be answered easily.
Energy production methods cause large earthquakes in the US
Hydraulic fracturing or ‘fracking’ has been in the news recently for allegedly causing minor earthquakes in localised areas, but new findings from three papers published in the journal Science indicate that the problem could be far more widespread. Other methods of energy production that involve injecting water into the ground, such as natural gas extraction and geothermal energy collection have caused numerous earthquakes across the United States, according to Nature.
William Ellsworth, author of one of the papers and seismologist at the US Geological Survey, says that the number of US earthquakes recorded at a magnitude over 3.0 have increased tenfold in the last decade. Nicholas van der Elst of Columbia University reports that more than half of earthquakes greater than 4.5 in magnitude in the last decade struck near water injection sites.
Together the studies are convincing evidence of a trend, and Ellsworth believes that injecting water into the ground can lubricate existing fault lines, increasing the likelihood of tremors being caused by earthquakes on the other side of the world. The Telegraph reports that a moratorium on fracking in the UK following earthquake fears was lifted in 2012 after little evidence was found for tremors caused by the water injections directly. This new evidence shows that in areas where water has been injected to extract oil or gas, tremors tend to occur at the same time as other large earthquakes far away.
Heather Savage, a co-author on the research from Columbia University told The Guardian: "It is already accepted that when we have very large earthquakes seismic waves travel all over the globe, but even though the waves are small when they reach the other side of the world, they still shake faults. This can trigger seismicity in seismically active areas such as volcanoes where there is already a high fluid pressure. But this is the first time the same has been recognised for areas with anthropogenically induced high fluid pressure."
Concrete innovation purifies city air
Dutch scientists have created special cement that converts harmful air pollutants such as nitrogen oxide into less-dangerous chemicals such as nitrates. It works using titanium oxide which, when exposed to sunlight, acts as a catalyst for the reaction. According to the Huffington Post, the researchers hope that the concrete will be used in urban areas, and can reduce the number of pollutants in the air by up to 45 per cent.
Previous attempts at the idea have produced passable results, but this is the most effective formulation so far. Co-author of the paper, Jos Brouwers of the Department of Architecture, claims that the increased cost of implementing the new cement would be in the region of ten per cent.