NEWS
ENERGY
EU renewables overtake coal
ANALYTICAL SCIENCE DNA detection kit ANTHONY KING
Discovered in 2012, the DNA scissors enzyme CRISPR-Cas9 has become an important tool in gene editing. Now, scientists led by Jennifer Doudna at University of California, Berkeley, US, report that another CRISPR enzyme – Cas12a – not only binds to and cuts double-stranded DNA, but also triggers shredding of all single-stranded DNA in a test tube. The discovery could usher in simple and
rapid tests for viral infections, boost our ability to detect bacterial infection, or even screen for cancer, Doudna and coworkers report (Science, doi:10.1126/science.aar6245). The scientists deployed their new
strategy in patient samples containing human papilloma virus (HPV). They accurately detected ‘high risk’ HPV types 16 and 18 in samples infected with many different HPV types in just one hour. Before beginning their detective work,
the researchers first amplified the target DNA to make it easier for the Cas12a to find it.
Synthetic single-stranded DNA added MARIA BURKE
Renewables outstripped coal power for the first time in electricity generation in Europe in 2017, according to a new report. The European Power Sector in 2017 – by think-tanks Sandbag and Agora Energiewende – predicts renewables could provide half of Europe’s electricity by 2030. Wind, solar and biomass generation
collectively rose by 12% in 2017 – to 679 Terawatt hours, generating 21% of Europe’s electricity, and contributing to 30% of the energy mix. ‘This is incredible progress considering just five years ago coal generation was more than twice that of wind, solar and biomass,’ the report states. However, growth is variable. Germany and the UK alone contributed to 56% of the expansion in the past three years. There is also a ‘bias’ for wind, with a 19% increase in 2017, due to good wind conditions and huge investments, the report says. ‘This is good news now the biomass boom is over, but bad news in that solar was responsible for just 14% of the renewables growth in 2014 to 2017.’ New analysis by trade group
WindEurope backs up the findings on
wind power, showing that countries across Europe installed more offshore capacity than ever before: 3.14GW. This corresponds to 560 new offshore wind turbines across 17 wind farms. Fourteen projects were fully completed and connected to the grid, including the first floating offshore wind farm. Europe now has a total installed offshore wind capacity of 15.78GW. Germany remains top of the European
league, with the largest total installed wind-power capacity; it installed 42% of the EU’s new capacity in 2017; followed by Spain, the UK and France. Denmark boasts the largest share of wind in its power mix at 44% of electricity demand. Separately, the US solar industry lost 9800 jobs in 2017, according to The Solar Foundation’s annual National Solar Jobs Census, the first time jobs have decreased since the first survey in 2010. It attributes the 4% drop to losses in mature markets like California and Massachusetts. The industry has also been concerned about tariffs on imported solar panels. At the same time, the long-term trend continues to show significant growth. Employment in the solar industry far outpaces that of the coal, wind and nuclear energy industries.
to the sample was immediately shredded, triggering the release of a fluorescent signal and showing that Cas12a had found and bound to its target. They dubbed the diagnostic system ‘DNA Endonuclease Targeted CRISPR Trans Report,’ or DETECTR. It involves combining all of the reagents in a single test tube: CRISPR-Cas12a, guide RNA, fluorescent reporter molecules and recombinase polymerase amplification (RPA). RPA is a new way to amplify DNA, without using expensive polymerase chain reaction (PCR), developed by TwistDX in Cambridge, UK. The researchers claim that DETECTR can
analyse cells, blood, saliva, urine and stool to detect genetic mutations, cancer and antibiotic resistance as well as diagnose bacterial and viral infections; with attomolar – 10-18
moles per litre – sensitivity. Used as a diagnostic tool in test tubes, this ability to shred single stranded DNA is potentially very useful, comments CRISPR researcher Malcolm White at the University of St Andrews, UK, who was not involved in the study. ‘A significant amount of fluorescent signal is generated from just a few molecules of DNA, which makes it easier to detect and so is very sensitive,’ he says. For human DNA engineering, he notes that this shredding activity of Cas12a would not be desirable, ‘because cells do generate single-stranded DNA during replication.’
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