For many people, the recent festive period was more about spending time with family, eating too much and being generally merry than it was about reading ground breaking science. As such, we’ve put together a quick recap of some of the things you may have missed.
Specific enzymes – produced in great numbers as a defensive response to viral attack in the model plant Arabidopsis thaliana – may actually harm the plants ability to fight infection. Nahid Shamandi, Matthias Zytnicki, Hervé Vaucheret and colleagues have shown that, when Arabidopsis is infected with a virus, levels of RNASE THREE-LIKE 1 (RTL1) enzymes rise in response. However, these enzymes counterproductively inhibit many classes of small interfering RNAs (siRNAs) that are known to aid the plant fight off viral infection. After disabling this extra line of defence, the ‘helpful’ RTL1 enzyme is then itself defeated by the virus’ own defensive systems. The authors also show that even artificially increasing the levels of RTL1 enzyme does not equate to a better defence against viral attack. Read the Synopsis.
Image Credit: 10.1371/journal.pbio.1002326.g002
The human adolescent brain is a notoriously complex place. However, Scott Marek, Beatriz Luna and colleagues have explored the developmental changes in the brain during this important stage of life.
Our brains are made up of a number of differently-functioning regions, which work together as networks to perform cognitive tasks. Communication between a given brain region and other regions outside of its own network is known as integration. By performing fMRI on nearly 200 young people aged between 10 and 26, the authors found that, although the regions making up each network do not change appreciably during adolescence, the amount of integration between networks continues to grow. They suggest brain networks become established before adolescence, after which the amount of cross-network integration increases as the brain continues to develop, leading to greater cognitive function.
Image Credit: 10.1371/journal.pbio.1002328
Metastasis – the spread of cancerous cells around the body – is one of the factors that can turn a localised tumour into a killer. The transcription factor ELF5, a protein that controls milk production in the breast after pregnancy, has been found to aid the spread of breast cancer cells. David Gallego-Ortega, Christopher Ormandy and colleagues have shown ELF5 helps tumours exploit the natural immune system to create blood vessels around them, allowing cancerous cells to metastasise to the lungs. Tying in with previous work by the authors, they now suggest that ELF5 proteins are responsible both for enabling the spread of cancerous cells and for increasing their resistance to treatments.
Image Credit: National Cancer Institute/Wikimedia Commons
Roots are essential to the survival of the majority of plant species, but are regularly eaten by below-ground herbivores. As such, it’s unsurprising that many species have evolved strategies to deter the attentions of would-be attackers.
The roots of the dandelion (Taraxacum officinale agg.) are often fed upon by larvae of the common cockchafer beetle (Melolontha melolontha). However, Meret Huber, Matthias Erb and colleagues have shown that the dandelion releases a chemical deterrent (taraxinic acid) in the sticky latex exuded from its roots when attacked, which can successfully ward off these larvae and protect the plant.
Image Credit: Meret Huber
Immunotherapy is the practice of manipulating the body’s own immune system to aid the fight against disease. One branch of immune response, known as the complement system, has been shown to most effectively attack targets that are ‘flagged’ by six antibodies binding as a ring on the cell surface. This is because the front line of the complement system involves the C1q complex, which has matching six-fold symmetry (see the top of this image). Now, Rob de Jong, Frank Beurskens, Paul Parren and colleagues have identified mutations of a specific antibody, IgG1, that they can use to enhance the formation of a six-membered ring (“hexamerisation”) and ultimately encourage the complement system to eradicate a greater number of harmful cells than it would do naturally.
Image Credit: Joost M. Bakker, ScicomVisuals