Wednesday, February 13, 2013

Red Queen's Race

Getting hard to stay ahead.

From Nature's news blog:

 Synthetic biologists have developed DNA modules that perform logic operations in living cells. These ‘genetic circuits’ could be used to track key moments in a cell’s life or, at the flick of a chemical switch, change a cell’s fate, the researchers say. Their results are described this week in Nature Biotechnology.

From Gardens of the Sun:
The window looked out across a huge spherical chamber carved out of the native ice and lit by a point source hung at the apex of its ceiling like a drop of incandescent blood. Its walls curved down to a floor creased with smooth ridges, and the top of each ridge was streaked with dark eddies and swirls and littered with dense copses of half-melted candles, phalanxes of tooth-like spikes, heaps of tangled wires or curled scrolls like spun sugar,meadows of brittle hairs, pods of paper-thin fins breaking out of the ice. All these growths stark black in the ruby light, apart from a large candle-copse close to the observation window that was clearly dying from the inside out, its lumpy spires crumbling into pale ash.

‘Vacuum organisms,’ Loc said. ‘A garden of vacuum organisms.’

He’d been expecting something truly exotic. A clone farm of superhuman babies. A wonderland full of weird plants and animals. A city of intelligent rats or raccoons. But these growths weren’t that much different from the vacuum organisms cultivated on the naked surface around every city and settlement on the moons of Saturn.

‘They look like vacuum organisms,’ Sri Hong-Owen said. ‘But they are not. They are not constructed from bound nanotech, but are spun from intricate pseudo-proteinaceous polymers. I call them polychines. If commercial vacuum organisms are synthetic analogues of prokaryotes - bacteria, Mr Ifrahim - these are analogues of the ancestors of prokaryotes.’

‘You want to give me a lecture,’ Loc said. ‘It would be easier if you cut to the chase, and told me exactly why these things are worthless. They certainly look worthless.’

Sri Hong-Owen ignored his sally, and told him that the chamber contained a methane-hydrogen atmosphere at minus twenty degrees Centigrade, far warmer than Mimas’s ambient temperature. ‘As for the polychines, they do not possess a pseudocellular structure; nor are they generated by the systematic execution of a centralised set of encoded instructions. Instead, they are networks of self-catalysing metabolic cycles created by interactions between specific structures in their polymers.’

‘Like carpets, or suit-liners.’

‘Very good, Mr Ifrahim. But although halflife materials are self-repairing and can even grow when fed the correct substrate, they encode only a very simple set of on/off instructions and can express only one morphology. The polychines are far more versatile. They are non-binary logic engines that use a form of photosynthesis to transform simple chemicals to complex polymers. They can reproduce, and they can even exchange information, although that information is entirely analogue in form. And they possess a limited set of components which obey a limited set of self-organising rules capable of generating new instructions, and, therefore, new properties and even new forms. Once I completely understand how those rules operate in every possible combination, it will be possible to manipulate the polychines to produce predictable states.’


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