Wednesday, 7 November 2012

News from the journals

A few interesting stories from recent papers published in scientific journals:

Soybeans adapt to Chernobyl's radioactive soil by improving their heavy metal tolerance

The disaster that occurred at Ukraine's Chernobyl Nuclear Power Plant in 1986 was probably the worst nuclear accident that there has ever been. But despite the devastating size of the disaster, plant life continues to grow in the radiation-contaminated area. In order to investigate how plants manage this surprising survival trick, a team of scientists from Ukraine and Slovakia planted soybean seeds in two fields in the Chernobyl area in 2007. The two fields were very similar in terms of soil type, but one of them was radioactive and the other one wasn't. A year later the scientists harvested and analysed the soybeans. They found that after a year's exposure to radiation the plants in the radioactive field were different, in a number of interesting ways, from the plants in the non-radioactive field. Notably, they had adapted to be more tolerant of the heavy metals that cause the nuclear contamination.

Like most scientists who do something cool because of curiosity, but need to find practical reasons to justify the funding they receive, the researchers end their recent paper by suggesting ways that further experiments into this subject could be useful. Their first suggestion is that with a better understanding of how plants adapt to the radioactive environment, it could be possible develop ways of growing biofuel crops in the area (which, for obvious reasons, is not currently used for growing food crops). If you think that this represents some serious out-of-the-box thinking, then wait until you see their second suggestion:
"With a little of imagination, it is also tempting to speculate that understanding plant adaptation toward ionizing radiation (cosmic radiation) will be necessary for plant cultivation for food purposes during long space missions in the future."
[Read this paper for yourself at:]

Using a computer model to test ideas about plant cell wall structure

Just like animals, all plants are made up of little bags of life called cells. In plants (but not in animals) each cell is surrounded by a rigid structure called the 'cell wall'. Cell walls give plants shape, strength and stability (qualities we achieve with our muscles and bones).

Although we know what components plant cell walls are made from, we still only have educated guesses about how these components are arranged. One of the most popular ideas is that strong tubes called 'cellulose microfibrils' (they are a bit like tiny scaffolding poles) are held together by long, stringy molecules called 'hemicelluloses', in an arrangement something like that shown in the diagram below. The theory is that this binding together of the cellulose microfibrils is what gives the cell wall its large amount of strength.

In order to test this idea, two researchers from Pennsylvania State University have created a computer simulation of a cell wall, complete with simulated cellulose microfibrils and simulated hemicelluloses to hold them together. Once the simulation had been produced, they asked the computer what would happen if the cell wall was stretched, and whether the result would be different if the links between the two components were removed.

They found that the presence of the links does make a big difference. Without them, the simulated cell wall was much less able to withstand stretching. This is an important piece of evidence which suggests that this arrangement may actually be how the components are arranged in real life. However, they also found that even with the links, the cell wall was still not strong enough to withstand certain types of stretching that real-life cell walls could easily cope with. This suggests that in real-life, cell walls must have other, additional mechanisms to resist stretching.

[Read this paper for yourself at:]

Genetically Modified Soybeans with increased beta-carotene content

A few weeks ago I wrote about Golden Rice, a variety of rice which has been genetically modified to produce beta-carotene (an important, but often absent, component of human nutrition). Now, a team of Korean researchers have genetically modified Soybean to do the same thing.

[Read this paper for yourself at:]

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