In experiments, sweet potatoes grown in Maryland and Alabama yielded two to three times as much carbohydrate for fuel ethanol production as field corn grown in those states, Agricultural Research Service (ARS) scientists report. The same was true of tropical cassava in Alabama.

The sweet potato carbohydrate yields approached the lower limits of those produced by sugarcane, the highest-yielding ethanol crop. Another advantage for sweet potatoes and cassava is that they require much less fertilizer and pesticide than corn.

Lew Ziska, a plant physiologist at the ARS Crop Systems and Global Change Laboratory in Beltsville, Md., and colleagues at Beltsville and at the ARS National Soil Dynamics Laboratory in Auburn, Ala., performed the study. The research is unique in comparing the root crops to corn, and in growing all three crops simultaneously in two different regions of the country.

The tests of corn, cassava and sweet potato were in the field at Beltsville, and in large soil bins at Auburn.

For the sweet potatoes, carbohydrate production was 4.2 tons an acre in Alabama and 5.7 tons an acre in Maryland. Carbohydrate production for cassava in Alabama was 4.4 tons an acre, compared to 1.2 tons an acre in Maryland. For corn, carbohydrate production was 1.5 tons an acre in Alabama and 2.5 tons an acre in Maryland.

The disadvantages to cassava and sweet potato are higher start-up costs, particularly because of increased labor at planting and harvesting times. If economical harvesting and processing techniques could be developed, the data suggests that sweet potato in Maryland and sweet potato and cassava in Alabama have greater potential than corn as ethanol sources.

Further studies are needed to get data on inputs of fertilizer, water, pesticides and estimates of energy efficiency. Overall, the data indicate it would be worthwhile to start pilot programs to study growing cassava and sweet potato for ethanol, especially on marginal lands.

Hydrogen will be one of the most important fuels of the future. It would be ideal to obtain hydrogen by splitting water instead of from petroleum. However, the electrolysis of water is a very energy intensive process, making it both expensive and unsustainable if the electricity necessary to generate it comes from the burning of fossil fuels. Photolysis, the splitting of water by light, is a highly promising alternative.

A team of Australian and American researchers has now developed a catalyst that effectively catalyzes one of the necessary half reactions, the photooxidation of water. As it reports in the journal Angewandte Chemie, the core of the catalyst is a manganese-containing complex modeled after those found in photosynthetic organisms.

Electrolysis is the reverse of the process that occurs in a battery: that is electrical energy is converted to chemical energy. The electrolysis of water involves two half reactions: at the cathode, protons (positively charged hydrogen ions) are reduced to hydrogen, whereas at the anode the oxidation of water produces oxygen. The goal of the researchers is to use sunlight to get this energy-intensive process going. To make this work, the light-harvesting power of modern solar cells must be combined with effective photocatalysts for the oxidation of water and reduction of hydrogen ions into hydrogen gas.

The biggest hurdle to overcome in the photocatalytic splitting of water to date has been the lack of a robust catalyst that oxidizes water. In fact, the best known catalyst, which very effectively oxidizes water when irradiated with visible light, is a manganese-containing enzyme in the photosynthetic apparatus of living organisms.

Robin Brimblecombe and Leone Spiccia at Monash University (Australia), Gerhard F. Swiegers at the Commonwealth Scientific and Industrial Research Organisation (CSIRO, Australia), and G. Charles Dismukes at Princeton University (USA) have used this structure as a model for their photocatalyst.

The catalyst in question is a manganese oxo complex with a cubic core made of four manganese and four oxygen atoms capped by ancillary phosphinate molecules. The catalytically active species is formed when energy from light causes the release of one the capping molecules from the cube.

However, the manganese complex is not soluble in water. The researchers have overcome this problem by coating one electrode with a wafer-thin Nafion membrane. Housed within the aqueous channels of this membrane, the catalytic species is stabilized and has good access to the water molecules. Irradiation with visible light under an applied 1.2 volts leads to the effective electro-oxidation of water.

This anodic half-cell could be easily paired with a catalytic hydrogen-producing cathode cell. This would result in a photoelectrochemical cell that produces pure hydrogen and oxygen from water and sunlight.

A somatic cell is generally taken to mean any cell forming the body of an organism. Somatic cells, by definition, are not germline cells.

In mammals, germline cells are the sperm and ova (also known as "gametes") which fuse during fertilization to produce a cell called a zygote, from which the entire mammalian embryo develops.

Every other cell type in the mammalian body, apart from the sperm and ova, the cells from which they are made (gametocytes) and undifferentiated stem cells, is a somatic cell; internal organs skin, bones, blood and connective tissue are all made up of somatic cells.

Harvard and Columbia scientists have for the first time used a new technique to transform an ALS (amyotrophic lateral sclerosis, or Lou Gehrig's disease) patient's skin cells into motor neurons, a process that may be used in the future to create tailor-made cells to treat the debilitating disease. he research – led by Kevin Eggan, Ph.D. of the Harvard Stem Cell Institute – will be published July 31 in the online version of the journal Science.

This is the first time that skin cells from a chronically-ill patient have been reprogrammed into a stem cell-like state, and then coaxed into the specific cell types that would be needed to understand and treat the disease.

Though cell replacement therapies are probably still years away, the new cells will solve a problem that has hindered ALS research for years: the inability to study a patient's motor neurons in the laboratory.

ALS is caused by the degeneration and death of motor neurons, the nerve cells which convey nerve impulses from the spinal cord to each of the body's muscles. The death of motor neurons leads to paralysis of these muscles, including those involved in swallowing and breathing, and ultimately leads to death of the patient. The disease affects about 30,000 people in the United States.

"Up until now, it's been impossible to get access to the neurons affected by ALS and, although everyone was excited by the potential of the new technology, it was uncertain that we would be able to obtain them from patients' skin cells," says co-author Chris Henderson, Ph.D., professor of pathology, neurology and neuroscience, co-director of the Center for Motor Neuron Biology and Disease at Columbia, and senior scientific advisor of the Project A.L.S./ Jenifer Estess Laboratory for Stem Cell Research. "Our paper now shows that we can generate hundreds of millions of motor neurons that are genetically identical to a patient's own neurons. This will be an immense help as we try to uncover the mechanisms behind this disease and screen for drugs that can prolong life."

The motor neurons were created using a new technique that reprograms human adult skin cells into cells that resemble embryonic stem (ES) cells. The technique used to make these cells – called induced pluripotent stem (iPS) cells – was a major advance in the field that was first reported last November by researchers in Japan and Wisconsin. Those studies used skin cells from healthy adults, but it remained unknown whether iPS cells could be created with cells from chronically-ill patients and then transformed into neurons. The Columbia-Harvard team, in this paper, showed this was possible using an ALS patient's skin cells.

Columbia clinician-researchers Wendy Chung, M.D., Ph.D., Herbert Irving Assistant Professor of Pediatrics in Medicine, and Hiroshi Mitsumoto, M.D., D.Sc., the Wesley J. Howe Professor of Neurology at Columbia, obtained skin cells from an 82-year-old ALS patient. In the Project A.L.S. laboratory, Columbia researchers Dr. Henderson and Hynek Wichterle, Ph.D., assistant professor of pathology, and colleagues cultured the cells and contributed expertise needed for identifying iPS cell-derived motor neurons. Finally, Harvard researchers, led by Kevin Eggan of the Harvard Stem Cell Institute, successfully used the new technique to reprogram the skin cells into iPS cells and differentiate them into motor neurons.

Scientists had originally hoped to create neurons and other adult cells using "therapeutic cloning," in which DNA from a patient is inserted into a donated egg to create embryonic stem cells. That technique, however, has still not been successful in humans, and is also hindered by a shortage of donated eggs.

If the iPS technique holds its promise in producing neurons and other cells for research, it will probably replace the "therapeutic cloning" approach, Dr. Henderson says, but there are still lots of questions about the iPS-derived neurons.

"We don't know yet how similar they are to the motor neurons in ALS patients," he says. "While the cells exhibit many properties that are typical of motor neurons, we don't yet know whether they will be prone to degeneration that will allow us to mimic the disease in the culture dish and therefore to screen potential drugs."

Researchers at Columbia and Harvard are already collaborating to investigate the cells with the ultimate goal of determining how they differ from a healthy person's motor neurons.

"Project A.L.S. has always maintained that collaboration between scientists is the answer to understanding and treating this disease," Valerie Estess, founder and research director, Project A.L.S. "We are thrilled to have catalyzed the Harvard-Columbia collaboration that led to this discovery."

"Therapeutic use of the cells is probably a long way off," Dr. Henderson says. "Right now there are safety issues with iPS cells, including a risk of cancer. We also don't know how to reintroduce cells into a sick adult in a way that will be beneficial. All these hurdles need to be overcome first before we can think about using the cells to treat disease, but we can start immediately to evaluate them as a tool for drug discovery."