Nature Biotechnology pp 1229 - 1232

Scientists have developed a highly efficient microbial fuel cell, a sort of ‘bacterial battery’ that produces electricity consistently and over long periods of time. Taking advantage of the unique characteristics of a bacterium, Rhodoferax ferrireducens, previously isolated from marine sediments, Swades Chaudhuri and Derek Lovley report in the October issue of Nature Biotechnology on the power producing capabilities of a fuel cell harboring this organism. Because R. ferrireducens is capable of transferring electrons generated while feeding on simple sugars such as glucose (the main form of sugar in the environment), fructose (abundantly found in fruits), sucrose (present in sugar cane and sugar beet) and xylose (a constituent of wood and straw) directly to an electrode, the efficiency in converting the energy contained in these sugars to electricity is over 80%. Previously, fuel cells achieving up to 50% efficiency in energy conversion had been described, but these were dependent on the use of unstable electron transfer mediators, and thus expensive and not suitable for long-term electricity generation.

Given the wide range of substrates Chaudhuri and Lovley’s fuel cell can be powered with, the use of microbial fuel cells to produce energy from sugar-containing waste materials is now one step closer to being realized.

Nature Biotechnology pp 1200 - 1207

In the first example of therapeutic cloning for treating a brain disorder, Lorenz Studer and colleagues have used dopamine neurons derived from cloned mouse embryonic stem (ES) cells to treat mice with a Parkinson-like condition. The study, published in the October issue of Nature Biotechnology, is only the second report of therapeutic cloning in animals.

A loss of dopamine neurons is a hallmark of Parkinson disease. Dopamine neurons derived from ES cells were previously shown to be effective in treating parkinsonian mice. But the cells in this earlier study expressed a transgene—raising safety concerns—and they had not been generated by cloning.

The goal of therapeutic cloning is to produce specialized cells needed to repair a failing organ from human ES cells generated by cloning the patient’s own cells. Unlike generic ES cells, such cloned ES cells and their specialized progeny would be genetically identical to the patient and could be transplanted without being rejected by the patient’s immune system. Although therapeutic cloning has great promise for treating many diseases, it has not yet been demonstrated in human patients.