Science news digest – 27th March 2014
In the science news this week, living materials could pave the way for greener manufacturing, dogs can recognise humans from their smell, and finally… newly discovered dwarf planet may be proof of Oort cloud.
Living materials could grow products
A Boston lab in the US have grown living materials, which in the future could lead to researchers being able to grow complex structures from cells programmed to assemble into intricate patterns, reports the BBC.
Biologist Timothy Lu and his team at the Massachusetts Institute of Technology, created living biofilms made from proteins tougher than steel, that were designed to incorporate semiconducting crystals and electrical wiring.
The biofilms have been created by a combination of advanced techniques in genetic engineering, which reprogramme a cell’s function, and the kind of protein chemistry found in the biofilm gloss on our teeth.
"Our vision is to create living materials, in which living cells grow, lay down biopolymers and control the inorganic compounds around them," Professor Lu explained.
"Just imagine what we could achieve if we could grow physical devices and structures from bottom up using cells and minimal inputs, rather than manufacture and shape them from top down."
The work from Lu and his team used previous developments in protein engineering, where complex, functional biopolymers self-assemble into scaffolds that other crystals then use to grow.
However, in this work, the proteins are produced by cells that have been reprogrammed using synthetic biology techniques, so that they can be used as switches to turn certain parts of the genome on and off at will.
In essence, Lu has created a biological computer circuit, with genetic switches that respond to chemical signals, and engineered genes that produce synthetic filaments of a protein called curli.
This means the bacteria secrete the protein matrix on demand either from stimulants being added by the researchers or from neighbouring cells.
The proteins have also been adapted so that inorganic materials, such as quantum dots, or metals, can grow on the scaffold. The team even programmed the bacteria to grow an electrical switch in one experiment.
"This is only a beginning," said Prof Lu. "We've shown that even with simple modifications we can get some pretty interesting materials. Downstream we'd like to try more sophisticated designs."
Dogs recognise their owners’ smell
Many dog owners will know how excited their dog gets when they see a familiar person in the distance or hear a car pull in to the driveway. New research shows that it’s not just audio and visual clues that can elicit canine emotion however, and that scent may be just as powerful.
When humans smell the familiar scent of someone they love, it’s common to experience an immediate rush of emotion, before any cognitive processes kick in. Scientists have this week revealed evidence that the same may also be true for dogs, and the fact that their olfactory sense is so much stronger than humans, mean the reaction is even more powerful.
The study, led by scientists at Emory University in Georgia USA, concluded that the scent of a dog’s owner lingers in the dog’s brain. Their research was published in the journal Behavioural Processes, and pinpoints the area of the canine brain that they believe responds particularly strongly to the smell of familiar humans.
So even if their owner is not physically present, dogs will respond with excitement to a familiar scent. Lead scientist Dr Gregory Burns explained to the Daily Telegraph:
“In our experiment… the scent donors were not physically present. That means the canine brain responses were being triggered by something distant in space and time. It shows that dogs' brains have these mental representations of us that persist when we're not there."
The experiment was conducted on dogs of various breeds, and involved a brain scan being carried out whilst they were exposed to five different scents from familiar and unfamiliar dogs and humans, one by one.
All five smells caused a response in the parts of the brain associated with detecting smells, and the results showed that the responses were strongest for the smell of familiar humans, followed by familiar dogs.
Dr Berns said: "This suggested that not only did the dogs discriminate the familiar human scent from the others, they had a positive association with it.
"While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the 'reward response' is reserved for their humans. Whether this is based on food, play, innate genetic predisposition or something else remains an area for future investigation."
Astronomers discover new dwarf planet
A dwarf planet at the outer edges of our Solar System has been discovered by astronomers, reported the Guardian.
The lump of ice and rock is roughly 450km wide and orbits the Sun at a distance greater than any other known object – at its closest it is 12 billion km away from the Sun, which is 80 times the distance of the Earth from the Sun.
The size of the object is still to be confirmed, but if it is, it would qualify as a dwarf planet in the same category as Pluto.
Astronomers believe this object could be the evidence that proves the existence of the inner Oort cloud, a region of icy bodies that lies beyond the orbit of Neptune.
Until the object is given an official name, it is known as 2012 VP113, or VP for short.