*Molecular electronics paves the way for DNA-based computer circuits*

The research could re-ignite interest in the use of DNA-based wires and devices in the development of programmable circuits that would be more sophisticated, cheaper and simpler to make.

By JUDY SIEGEL-ITZKOVICH
A scientist looks through a microscope (photo credit: INGIMAGE)
A scientist looks through a microscope
(photo credit: INGIMAGE)
An international group of scientists that includes a group at the Hebrew University in Jerusalem have announced the most significant breakthrough in a decade toward developing DNA-based electrical circuits, and published their findings in Nature Nanotechnology.
The research could re-ignite interest in the use of DNA-based wires and devices in the development of programmable circuits that would be more sophisticated, cheaper and simpler to make.
The central technological revolution of the 20th century was the development of computers, leading to the communications and Internet era. The main measure of this evolution is miniaturization – making machines smaller. A computer with the memory of the average laptop today was the size of a tennis court in the 1970s.
Yet while scientists made great strides in reducing of the size of individual computer components through microelectronics, they have been less successful at reducing the distance between transistors, the main element of computers. These spaces between transistors have been much more challenging and extremely expensive to miniaturize – an obstacle that limits the future development of computers.
Molecular electronics, which uses molecules as building blocks for the fabrication of electronic components, was seen as the ultimate solution to the miniaturization challenge. But so far, no one has actually been able to make complex electrical circuits using molecules.
The only known molecules that can be pre-designed to self-assemble into complex miniature circuits, which could in turn be used in computers, are DNA molecules.
But no one has yet been able to demonstrate reliably and quantitatively the flow of electrical current through long DNA molecules.
Now, the international group led by HU Prof. Danny Porath of the chemistry institute report reproducible and quantitative measurements of electricity flow through long molecules made of four DNA strands, signaling a significant breakthrough towards the development of DNA-based electrical circuits. The research was carried out in collaboration with groups from Denmark, Spain, the US, Italy and Cyprus.
According to Prof. Porath, “This research paves the way for implementing DNAbased programmable circuits for molecular electronics, which could lead to a new generation of computers.”
REPTILES WITH ‘BAD HABITS’ DIE FASTER
If you want to live longer, you should be a vegetarian and abstain from sex until late in life – at least if you’re a snake or lizard. Researchers at the University of Lincoln in the UK investigated how longevity of scaled reptiles (Lepidosaurs) is influenced by key environmental characteristics and by their feeding and sexual habits and published their findings in Global Ecology and Biogeography.
Based on a worldwide study, involving 1,014 species, including 672 lizards and 336 snakes, it was found that a higher frequency of laying or giving birth and early sexual maturation are associated with shortened longevity.
Co-author Dr. Daniel Pincheira-Donoso, said: “We observed that more sex (or at least more pregnancies) means shorter life, very much like the rock star adage ‘Live fast, die young.’ Along the same lines, the study revealed that reptiles that sexually mature at a younger age will likely have shorter lives, while those who prefer to delay sexual maturity will probably live longer. And lastly, we found that vegetarians live longer than their carnivorous counterparts. Vegetal food is an intrinsically low-nutrition food, so we think that those who have these diets experience a reduction in reproductive rates, which in turn increases their lifespan.”
The results support key predictions from life-history theory and suggest that reproducing more slowly and at older ages and being herbivorous result in increased longevity.
The scientists found that long-living scaled reptiles are generally characterized by “slow” life-history traits: delayed and infrequent reproduction, smaller clutches, larger hatchlings and colder body temperatures. High investment in reproduction, expressed in frequent, large clutches is correlated with short life – but species with large eggs compared to their size live longer.
The team also discovered that herbivores live longer than similar-sized carnivores.
Ingestion of a protein-rich, meat diet may lead to faster growth, earlier and more intense reproduction and hence to shortened longevity. Herbivorous individuals probably consume poorer food, so reach maturity later and live longer. It could also be that hunting is more risky than collecting fruits and vegetables. The study provided the first large-scale, comparative study of longevity in cold-blooded animals and opens many avenues for further research on the attributes that govern longevity in this group.