ACS Chemistry for Life

Discovery of the secrets that enable plants near Chernobyl to shrug off radiation
Environmental Science & Technology

Martin Hajduch and colleagues note that plants had an unexpected ability to adapt to an environment contaminated with radiation following the April 26, 1986 accident at the Chernobyl Nuclear Power Plant. Their previous research, for example, showed that soybean plants in the area have adapted to the contaminated soil with certain changes in their proteome. A proteome is the full complement of proteins produced by the genes in a plant or animal. The scientists grew flax seeds in radiation-contaminated soil in the Chernobyl region and compared their growth to those of seeds grown in non-radioactive soil. Radiation exposure had relatively little effect on the protein levels in the plants, with only about five percent of the proteins altered, they note. Among them were certain proteins involved in cell signaling, or chemical communication, which might help the plants shrug off radioactivity, the scientists suggest.

Study advises Chinese government to change fuel in millions of households
Environmental Science & Technology

Scientists in China are recommending that the Chinese government consider phasing out the direct burning of traditional chunks of coal in millions of households. Yingjun Chen and colleagues suggest that the government substitute coal briquettes and improved stoves for cooking and heating to help reduce the country’s high air pollution levels. The scientists compared emissions between traditional and improved stoves using either raw (unprocessed) coal chunks or coal briquettes. The briquettes consist of coal powder and clay and are molded into multihole columns. They found that burning briquettes in well-ventilated stoves dramatically reduced black carbon emissions by 98 percent and other emissions by more than 60 percent. The study concludes that this approach can bring about “explicit benefits in environment and health, together with possible gains in climate stabilization.”

Secrets of plant warfare underpin quest for safer, more secure global food supply
Chemical & Engineering News

Like espionage agents probing an enemy’s fortifications, scientists are snooping out the innermost secrets of the amazing defense mechanisms that plants use to protect themselves from diseases to enhance the safety and security of the global food supply. C&EN Associate Editor Sarah Everts notes that plants use a battery of cunning mechanisms to protect themselves from disease. When microbes breach those immune defenses, epidemics like the Irish potato famine or wheat stem rust can mean starvation and displacement for millions of people. Over the last 20 years, for instance, scientists have made inroads into the complex chemical architecture of those defenses. The insights include the identification of a gene for the first receptor protein involved in plant immunity as well as the discovery of plant structures that recognize invading microorganisms. Those and other insights could underpin development of more effective and more sustainable ways of fighting crop pests.

Cocaine production increases destruction of Colombia’s rainforests
Environmental Science & Technology

Cultivating coca bushes, the source of cocaine, is speeding up destruction of rainforests in Colombia and threatening the region’s “hotspots” of plant and animal diversity. Liliana M. Dávalos and colleagues underscore the need for establishing larger protected areas to help preserve biodiversity. Their analysis of data from 2002-2007 on the effects of coca cultivation on deforestation of rainforests in Colombia identified several factors that boosted the likelihood that rainforest would be destroyed. In southern Colombia forest close to newly developed coca farms, for instance, was likely to be cut, as was land in areas where much of the farmland was devoted to coca. This is the first time the indirect impact on deforestation from cultivation destined for the global cocaine market has been quantified across South America’s biodiversity hotspots. Establishing larger protected areas in the region could help control deforestation and preserve biodiversity, the report suggests.

Greener process for key ingredient for everything from paint to diapers
Environmental Science & Technology

Weijie Ji, Chak-Tong Au, and colleagues are reporting discovery of an environmentally friendly way to make a key industrial material – used in products ranging from paints to diapers – from a renewable raw material without touching the traditional pricey and increasingly scarce petroleum-based starting material. Acrylic acid is typically made from propylene obtained from petroleum, and is essential for making paints, adhesives, textiles, leather treatments, and hundreds of other products. With prices rising, manufacturers have been seeking alternative ways of making acrylic acid without buying propylene, including making it from lactic acid. But current processes for using lactic acid are inefficient, less selective, and require higher temperatures and the accompanying high inputs of energy. The scientists’ potential solution is a new catalyst that can convert lactic acid into acrylic acid more efficiently. Lactic acid is a classic renewable starting material, produced by bacteria growing in vats of biomass such as glucose and starch from plants. In laboratory studies, the scientists showed that the new catalyst can convert lactic acid to acrylic acid more selectively at lower temperatures.

Night games in sports stadiums and street lighting can cause spike in daytime ozone air pollution
Chemical & Engineering News

Researchers have discovered – in a classic case of scientific serendipity – that the bright light from sports stadiums and urban street lights may boost daytime levels of ozone, a key air pollutant in many heavily populated areas. C&EN Associate Editor Jyllian Kemsley describes a so-called “field campaign” that took place in southern California and Mexico last year. It was a far-ranging effort by land, sea, and air to gain a deeper scientific understanding of all the factors involved in air quality and climate change. One of experiments involved use of detectors to measure the intensity of sunlight from an airplane. As the plane flew over a brightly lit sports stadium, one of the crew suggested, perhaps only half seriously, turning the device on, even though it was the dead of night. Much to the scientists’ surprise, they found there was enough light to drive certain chemical reactions in the atmosphere that would boost daytime levels of ozone, one of the most prevalent and difficult-to-control air pollutants in urban areas.

Banana peels get a second life as water purifier
Industrial & Engineering Chemistry Research

Gustavo Castro and colleagues report that minced banana peel performs better than an array of other materials in purifying drinking water contaminated with potentially toxic metals. They note that mining processes, runoff from farms, and industrial wastes can all put heavy metals, such as lead and copper, into waterways, which can have adverse health and environmental effects. Current methods of removing heavy metals from water are expensive, and some substances used in the process are toxic themselves. The researchers found that minced banana peel could quickly remove lead and copper from river water as well as, or better than, many other materials. A purification apparatus made of banana peels can be used up to 11 times without losing its metal-binding properties, they note. The team adds that banana peels are very attractive as water purifiers because of their low cost and because they don’t have to be chemically modified in order to work.

Tungsten may not be the best shot for making “green” bullets
Chemical Research in Toxicology

With efforts underway to ban lead-based ammunition as a potential health and environmental hazard, scientists are reporting new evidence that a prime alternative material for bullets – tungsten – may not be a good substitute. The report by Jose Centeno and colleagues found that tungsten accumulates in major structures of the immune system in animals. Tungsten alloys have been introduced as a replacement for lead in bullets and other munitions due to concerns that lead from spent ammunition could harm wildlife when it dissolves into water in the soil, streams, and lakes. Scientists thought that tungsten was relatively non-toxic, and a “green” replacement for lead, but recent studies suggest otherwise. Centeno’s group added small amounts of a tungsten compound to the drinking water of laboratory mice, used as surrogates for people in such research, and examined the organs and tissues to see exactly where tungsten ended up. The highest concentrations of tungsten were in the spleen, one of the main components of the immune system, and the bones, the center or “marrow” of which is the initial source of all the cells of the immune system, but further research will be needed to determine what effects, if any, tungsten may have on functioning of the immune system.

New antibacterial material for bandages, food packaging, shoes
ACS Nano

Chunhai Fan, Qing Huang, and colleagues have developed a new form of paper with the built-in ability to fight disease-causing bacteria could have applications that range from anti-bacterial bandages to food packaging that keeps food fresher longer to shoes that ward off foot odor. Scientists have tried to use graphene in solar cells, computer chips, and sensors. Fan and Huang decided to see how graphene affects living cells. So they made sheets of paper from graphene oxide, and then tried to grow bacteria and human cells on top. Bacteria were unable to grow on the paper, and it had little adverse effect on human cells.

Regrowing lost limbs
Chemical & Engineering News

C&EN Senior Editor Sophie Rovner notes that salamanders, flatworms, and certain other creatures can easily regrow lost body parts, including organs, nerves, and muscle, providing clues to regenerating human limbs. People can grow new skin and nerves, for instance, but regrowing an entire arm or leg seems like pure science fiction. Scientists have discovered certain proteins and genes with key roles in regenerating lost body parts. Certain chemicals in the amniotic fluid that cushions and protects fetuses prior to birth may help promote regeneration in adult mammals. There are other hints that electricity might be used to help jump-start regeneration.

Solving the mystery of bone loss from drug for epilepsy and bipolar disorder
Journal of Proteome Research

Glenn Morris and colleagues report a possible explanation for the bone loss that may occur following long-term use of a medicine widely used to treat epilepsy, bipolar disorder, and other conditions. The drug, valproate, appears to reduce the formation of two key proteins important for bone strength, they said. Valproate now is prescribed for mood disorders, migraine headache, and spinal muscular atrophy (SMA), a rare genetic disease that causes loss of muscle control and movement. Many SMA patients develop weak bones as a result of the disease itself, making further bone loss from valproate especially undesirable. The researchers found that valproate reduced production of collagen, the key protein that gives bone its strength, by almost 60 percent. The drug also reduced levels of osteonectin, which binds calcium and helps maintain bone mass, by 28 percent.

Deathstalker scorpion venom could improve gene therapy for brain cancer
ACS Nano

Miqin Zhang and colleagues note that chlorotoxin, an ingredient in the venom of the “deathstalker” scorpion could help gene therapy become an effective treatment for brain cancer. Difficulties in getting genes to enter cancer cells and concerns over the safety and potential side effects of substances used to transport these genes have kept the approach from helping patients. Chlorotoxin allows therapeutic genes to reach more brain cancer cells and slow their spread better than current approaches. In tests on lab mice, the scientists demonstrated that their venom-based nanoparticles can induce nearly twice the amount of gene expression in brain cancer cells as nanoparticles that do not contain the venom ingredient.

Advance toward earlier detection of melanoma
ACS Nano

Lihong Wang, Younan Xia, and colleagues are reporting development of a substance to enhance the visibility of skin cancer cells during scans with an advanced medical imaging system that combines ultrasound and light. The five-year survival rate for melanoma is about 98 percent if detected early but can be as low as 15 percent when detected at an advanced stage. Existing imaging techniques for early detection of melanoma produce low-quality images, “seeing” only a fraction of an inch below the skin, and use potentially harmful radioactive materials. A promising new technique called photoacoustic tomography (PAT) can overcome these problems, but the PAT system lacks an optimal contrast agent that can easily enter skin cancer cells and make them visible. The scientists developed such an agent by attaching a peptide (one of the building blocks of proteins) that targets skin cancer cells to gold “nanocages.” When injected into mice with skin cancer, the nanocages improved the image quality of the cancer cells by three-fold compared to nanoparticles lacking the peptide. The gold nanocages also show promise as a way to kill skin cancer cells using heat or anti-cancer drugs, they add.

New evidence that fat cells are not just dormant storage depots for calories
Journal of Proteome Research

Anja Rosenow and colleagues are reporting new evidence that the fat tissue in those spare tires and lower belly pooches – far from being a dormant storage depot for surplus calories – is an active organ that sends chemical signals to other parts of the body, perhaps increasing the risk of heart attacks, cancer, and other diseases. They are reporting discovery of 20 new hormones and other substances not previously known to be secreted into the blood by human fat cells and verification that fat secretes dozens of hormones and other chemical messengers. Among those hormones is leptin, which controls appetite, and adiponectin, which makes the body more sensitive to insulin and controls blood sugar levels. However, little is known about most of the proteins produced by the billions of fat cells in the adult body. The scientists identified 80 different proteins produced by the fat cells, including six new proteins and 20 proteins that have not been previously detected in human fat cells. The findings could pave the way for a better understanding of the role that hormone-secreting fat cells play in heart disease, diabetes, and other diseases.

No longer just a spectator, silicon oxide gets into the electronics action on computer chips
Journal of the American Chemical Society

Jun Yao, Douglas Natelson, Lin Zhong, and James Tour are documenting that one fundamental component of computer chips, long regarded as a passive bystander, can actually be made to act like a switch. That potentially allows it to take part in the electronic processes that power cell phones, iPads, computers, and thousands of other products. They document the multiple ways in which silicon dioxide, long regarded simply as an electric insulator, gets involved in the action. They explain that manufacturers have long used silicon oxide, normally a very poor conductor of electricity, as both a supportive and insulating material in electronics. The scientists recently showed, however, that the oxide material can be converted to a switchable conductor by an electrical process. This phenomenon may hold the key to developing a new generation of smaller, more powerful computer chips, but the mechanism behind this switching was unclear, until now.

Advance could speed use of genetic material RNA in nanotechnology
ACS Nano

Peixuan Guo and colleagues describe development of a highly stable RNA nanoparticle overcoming a major barrier to the use of the genetic material RNA in nanotechnology – the field that involves building machines thousands of times smaller than the width of a human hair and now is dominated by its cousin, DNA. They point out that DNA, the double-stranded genetic blueprint of life, and RNA, its single-stranded cousin, share common chemical features that can serve as building blocks for making nanostructures and nanodevices. In some ways, RNA even has advantages over DNA. However, the chemical instability of RNA and its tendency to breakdown in the presence of enzymes have slowed progress in the field. They tested its ability to power the nano-sized biological motor of a certain bacteriophage – a virus that infects bacteria – that operates using molecules of RNA. The modified RNA showed excellent biological activity similar, even in the presence of high concentrations of enzymes that normally breakdown RNA.