Plants doing quantum physics

This week the fledgling field of quantum biology took a major step forward with the publication of a significant study in Science.

In the study, scientist, Niek van Hulst, and colleagues at the Institute of Photonic Sciences in Castelldefels in Spain, outlined a extensive set of experiments which give the most concrete evidence yet of quantum principles being involved with the process of photosynthesis in plants. 

The study, whilst not the first to suggest that quantum processes are involved in photosynthesis, is important, as until now, no one had directly observed the impact of this kind of quantum mechanism at work, at room temperature.

As Jason Palmer writes: "Plants gather packets of light called photons, shuttling them deep into their cells where their energy is converted with extraordinary efficiency. [Š] An effect called a "coherence" helps determine the most efficient path for the photons. [....] The new study has been done painstakingly, aiming lasers at single molecules of the light-harvesting machinery to show how light is funnelled to the so-called reaction centres within plants where light energy is converted into chemical energy."

Quantum mechanics tends to be observed at very small, subatomic scales and at extremely cold temperatures. Organisms as large, wet and warm as plants have largely been understood using the principles of "classical physics".  But, the field of quantum biology has for some years now been suggesting a far deeper entanglement between large complex biological organisms and quantum mechanics.  Various research groups have shown that efficient energy transport in plants is connected to a quantum-mechanical phenomenon. In 2007, Berkeley Lab and the University of California published a paper in Nature that suggested that electronic quantum coherence played a role in photosynthesis.

This week's paper by the Institute of Photonic Sciences' underscores this, and provides compelling evidence. As Rienk van Grondelle of the Free University Amsterdam noted in an interview with the BBC, it is, "a very nice proof that the ideas that existed about these coherences are actually correct".

The research paves the way for far closer links between two fields of science - quantum physics and biology - often considered, with some humour, as polar opposites.  Greater collaborations between quantum physicists and biologists is likely to lead to important new insights in the coming years.  It is hoped by many scientists that understanding how quantum processes are involved in how plants harness energy could be applied to the development of, for example, more efficient solar cells, something which has been discussed for a few years now.

The field of quantum biology may just be coming of age.

Sources:
http://www.sciencedaily.com/releases/2013/06/130620142932.htm
http://www.scienceworldreport.com/

http://www.icfo.eu/

Oxygen discovered on Saturn's moon, Dione

Since the space probes, Galileo and Cassini, began sending ever more precise data from the farther reaches of the solar system, the Saturnian moon system has provided astronomers with a more-or-less constant stream of incredible information.

The latest discovery is that Saturn's moon, Dione, has an oxygen atmosphere.

Los Alamos National Laboratory announced this week that their scientists have detected molecular oxygen ions (O2+) in the upper atmosphere of the moon.

A sensor aboard the Cassini spacecraft called the Cassini Plasma Spectrometer (CAPS) detected the oxygen ions in Dione's wake during a flyby of the moon two years ago. Researchers Robert Tokar and Michelle Thomsen noticed the presence of the oxygen ions, and published their results in Geophysical Research Letters.

Robert Tokar notes:
"The concentration of oxygen in Dione's atmosphere is roughly similar to what you would find in Earth's atmosphere at an altitude of about 300 miles. It's not enough to sustain life, but, together with similar observations of other moons around Saturn and Jupiter, these are definitive examples of a process by which a lot of oxygen can be produced in icy celestial bodies that are bombarded by charged particles or photons from the Sun or whatever light source happens to be nearby."

The discovery is already generating interest within the astrobiology community. If oxygen exists on Dione, then why not also on some of the solar system's other moons? If oxygen is present on a moon within our solar system which is known to have sub-surface water - such as the Jovian moon, Europa - that oxygen could combine with carbon in subsurface lakes to form the building blocks of life.

Astronomy journalist, Jason Major notes:

"On Dione the energy source is Saturn's powerful magnetic field. As the moon orbits the giant planet, charged ions in Saturn's magnetosphere slam into the surface of Dione, stripping oxygen from the ice on its surface and crust. This molecular oxygen flows into Dione's exosphere, where it is then steadily blown into space by - once again - Saturn's magnetic field.

[...] Molecular oxygen, if present on other moons as well could potentially bond with carbon in subsurface water to form the building blocks of life. Since there's lots of water ice on moons in the outer solar system, as well as some very powerful magnetic fields emanating from planets like Jupiter and Saturn, there's no reason to think there isn't more oxygen to be found? in our solar system or elsewhere."

Dione was discovered by renown Italian-French astronomer, Giovanni Cassini (who the Cassini spaceprobe is named after) in 1684. It is one of 62 known moons which orbit Saturn, and is is the 15th largest. It is composed primarily of water ice and shared many physical features with it's neighbour, Rhea.

Sources: http://www.lanl.gov & http://www.agu.org/pubs/crossref/2012/2011GL050452.shtml

Spider-goats and the Rise of Synthetic Biology

Spider-goats, synthetic neurobiology and bio-hacking - Adam Rutherford's recent synthetic biology documentary for the BBC's flagship science programme, Horizon, is an important compendium of cutting edge ideas. Equal parts fascinating and disturbing, the documentary, provocatively entitled Playing God, was an overview of how synthetic biologists are breaking down nature into spare parts, and rebuilding it however they please.

Rutherford began by introducing viewers to "spider-goats" - goats which have been cross-bred with spiders, so that they excrete spider-silk in their milk.

Spider-silk is among the strongest materials which occurs in nature, but it's practical use to science has been limited by the relatively tiny amounts that scientists can extract from spiders. Spiders are notoriously impossible to farm, due to their cannibalistic nature. So scientists at Utah State University have come up with an ingenious method of producing spider-silk in industrial quantities.

As Rutherford explains in an article for The Observer, Randy Lewis, a professor of genetics at Utah, took the gene that encodes silk from an orb-weaver spider, and placed it among the DNA that prompts milk production in the goats. This genetic circuit was then inserted in an egg and implanted into a mother goat. Now, when the goats lactate, their milk contains spider-silk protein. The practical use for large quantities of spider-silk are numerous, but Lewis is interested in it's medical potential. He notes, "we already know that we can produce spider silk that's good enough to be used in ligament repair. [....] We've done some studies that show that you can put it in the body and you don't get inflammation and get ill."

The documentary further probed the medical implications for this type of work by introducing Ron Weiss's work at MIT. Weiss's team are creating living programmable machines that seek and destroy only the cells that cause disease. Using BioBricks, they have built a "cancer assassin cell". It distinguishes a cancer cell from a healthy cell using a set of five criteria. It then destroys the tumour cell if it satisfied those conditions. As Rutherford notes, "this sniper targeting is the opposite of the blunderbuss approach of chemotherapy, which can destroy both tumour and healthy cells with reckless abandon."

The documentary also probed how relatively simple it has become to experiment with synthetic biology, due to the popularisation of BioBricks and the emergence of biohacking and biology-hobbyists such as BioCurious. After visiting the BioCurious hobby space in the States, Rutherford comments: "there, high-school students were learning about biology by introducing fluorescent proteins from deep-sea jellyfish into bacteria to make them glow in the dark. In 2009, three scientists won Nobel prizes for this work. Already, it is literally child's play."

The documentary analyses industrial applications of synthetic biology, such as the development of synthetic biodiesel. Biotech companies Amyris have modified brewer's yeast so that instead of fermenting sugar to produce alcohol, diesel seeps out of every cell. The biodiesel is already in use.

Rutherford takes a balanced approach to the field, giving watchdog and campaign group, ETC, an opportunity to point of the risks of producing synethetic organisms on an industrial scale.. Their stance on synthetic biology can be found here.

This fascinating documentary and the companion article in The Observer, which documents the main narrative, is an excellent primer to an incredibly fast-moving field.

Sources:
BBC Horizon
The Observer

Guardian Podcast