This image shows how the CRISPR surveillance complex is disabled by two copies of anti-CRISPR protein AcrF1 (red) and one AcrF2 (light green). These anti-CRISPRs block access to the CRISPR RNA (green tube) preventing the surveillance complex from scanning and targeting invading viral DNA for destruction. Credit: Image from Lander Lab/The Scripps Research Institute

Scientists now reveal how viruses disable bacterial immune systems. For many bacteria, one line of defense against viral infection is a sophisticated RNA-guided “immune system” called CRISPR-Cas. At the center of this system is a surveillance complex that recognizes viral DNA and triggers its destruction...

How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of various biological systems? This is the fascinating question addressed by Antonio Suma and Cristian Micheletti, researchers at the International School for Advanced Studies (SISSA) in Trieste who used computer simulations to investigate the options available to the genetic material in such situations. The study has just been published in PNAS, the journal of the National Academy of Sciences of the Unites States. Credit: Antonio Suma, SISSA

How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of various biological systems? This is the fascinating question addressed by Antonio Suma and Cristian Micheletti, re...

1. Iowa State engineers don’t need a plow to clear snow from the heated test slabs they installed at the Des Moines International Airport. Larger photo. Photos courtesy of Halil Ceylan.
2. A thermal image of the heated airport pavements.

Engineers have installed 2 test slabs of electrically conductive concrete and the pavement has effectively cleared ice and snow. Iowa State University’s Halil Ceylan picked up his smartphone, opened up an app and called up the remote controls for the first full-scale test slabs. When a winter storm approaches, Ceylan can use that app to turn on the heated pavement system and, thanks to real-time video capability, watch as snow and ice melts away.

Late last fall Prof...

Artist’s impression of stars born in winds from supermassive black holes. Credit: ESO/M. Kornmesser

MUSE and X-shooter instruments on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile have been used to study an ongoing collision between two galaxies, known collectively as IRAS F23128-5919, 600 million light-years from Earth. The group observed the outflows – that originate near the supermassive black hole at the heart of the pair’s southern galaxy, and have found the first clear evidence that stars are being born within them. The discovery has many consequences for understanding galaxy properties and evolution.

Such galactic outflows are driven by the huge energy output from the active and turbulent centres of galaxies...