SCIENCE & TECHNOLOGY CONCENTRATES
MORE FRACKING STUDIES The overall water consumption of hydraulic fracturing to extract oil and natural gas and the technology’s impact on climate change and local air and water pollution compare favorably with other energy sources, such as burning coal, using nuclear fuel, or producing ethanol, according to a new study. A team of environmental scientists came to that conclusion after analyzing 165 academic studies and government databases in an effort to evaluate the environmental costs and benefits of fracking (Annu. Rev. Environ. Resour. 2014, DOI: 10.1146/annurevenviron-031113-144051). Meanwhile, a separate study by some of the same researchers supports prior studies in showing that the drilling and fracturing process is not directly to blame for well-publicized cases of groundwater contamination. By sampling hydrocarbon and noble-gas isotopes in oil, natural gas, and water wells, the researchers found that rare cases of pollutants showing up in well water stems from defective steel and cement casings in fracking wells or from gas formations not linked to fracturing zones (Proc. Natl. Acad. Sci. USA 2014, DOI: 10.1073/pnas.1322107111). Both studies suggest that issuing and enforcing regulations on well construction, inspections, and water treatment are the primary means of managing current and long-term environmental costs and ensuring the most economic benefit from fracking.—SR
Researchers have developed a method for detecting condition-dependent changes in protein conformations in biological samples such as cell lysates. The method paves the way for the discovery of protein biomarkers for diagnosing diseases and other apHeme plications on the basis of changes in protein structure in addition to changes in abundance. Paola Picotti of ETH Zurich and coworkers achieve this with a two-step protein digestion coupled to mass spectrometry (Nat. Biotechnol. Helix F Loop 2014, DOI: 10.1038/nbt.2999). The first digestion is performed UNFOLDING A two-step digestion method on proteins in their native state combined with mass spectrometry can detect by selecting and using a protease structural changes in myoglobin that has released its heme group. enzyme that cleaves proteins on the basis of their structure. In the second step, those pieces are digested further under denaturing conditions by trypsin, a protease that cleaves proteins at sequence-specific sites. Variations in the resulting peptide patterns before and after changing conditions, such as adding a drug, reveal proteins that undergo conformational changes. The researchers showed they can detect drastic or subtle conformational changes even in the complex chemical makeup of a cell extract. For example, they detected the transformation of α-synuclein from a single unfolded protein to a β-sheet-rich fibril of proteins and the unfolding of a single α-helix of myoglobin that has released its heme group.—CHA
Bleaching agents such as hydrogen peroxide lighten hair by oxidizing its melanin pigment. But the agents also induce other chemical changes, not all of which are desirable or understood. Getting to the root of these modifications could help scientists develop better products for protecting or repairing Untreated hair human hair. Researchers led by Gustavo S. Luengo of personal care AFM and FTIR revealed how bleaching exposes SO3– groups on hair’s keratin surface.
L ANGMUIR
MAPPING DAMAGED MANE DOMAINS
products manufacturer L’Oréal and Sabri Akari of contract research firm NanoCraft Coating have launched what they say is the most comprehensive study of hair surface chemistry to date (Langmuir 2014, DOI: 10.1021/la500461y). The team showed that H2O2 strips hair of its natural hydrophobic lipid coating, exposing charged sulfite groups of cysteic acid molecules in micro- and nanoscopic clusters. FTIR spectroscopy allowed the researchers to identify the molecules bound to the keratin surface of the hair cuticle. They also scanned hairs with atomic force miO O O O O S S S S S croscopy (AFM) using chemically modified Keratin tips for the first time. The researchers used O O O O O O methyl-terminated tips S S S O O O to map a hair strand’s hydrophobicity and Keratin aminated tips to probe its electronic charge –
100 µm Bleached hair
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profile with nanometer resolution, revealing the size and spacing of damaged domains. These results, Luengo says, “help us understand the surface of hair so we can better take care of it.”—MD
SEABORGIUM CARBONYL COMPLEX CREATED Scientists have succeeded in creating 18 molecules of a seaborgium carbonyl complex, Sg(CO)6. Seaborgium and other transactinides can be created only in particle accelerators, but studies of their chemistry help determine the accuracy of chemical theory and whether an element’s position in the periodic table correctly reflects its reactivity. The properties of transactinides are uncertain because those elements are subject to relativistic effects in which the innermost s orbitals contract, outer d and f orbitals expand, and electron energy levels split as a result of spin-orbit coupling—all affecting an element’s reactivity. A team working at Japan’s RIKEN Nishina Center for Accelerator-Based Science led by Christoph E.
NAT. BIOTECHNOL.
DECIPHERING PROTEINS
SCIENCE & TECHNOLOGY CONCENTRATES
Düllmann of Johannes Gutenberg University, Mainz, in Germany, created Sg(CO)6 by bombarding a 248Cm target with 22Ne and then magnetically separating seaborgium and its group 6 neighbors molybdenum and tungsten from other products (Science 2014, DOI: 10.1126/science.1255720). They next treated the metals with carbon monoxide and funneled them to a silica gas chromatography column lined with radiation detectors to identify the species. Sg(CO)6 adsorption to the column was similar to Mo(CO)6 and W(CO)6 adsorption, which the researchers say confirms theoretical predictions.—JK
CORD BLOOD STEM-CELL TRANSPLANT BOOSTER
tions of bacteria that colonize the digestive tract and lead to elevated blood sugar levels, a harbinger of diabetes (Nature 2014, DOI: 10.1038/nature13793). A research team led by Eran Elinav of Weizmann Institute of Science, in Israel, gave mice drinking water supplemented with glucose and an artificial sweetener. The mice developed elevated blood sugar levels compared with mice drinking water alone or water with just sugar in it. When the team gave the mice an antibiotic that wiped out gut bacteria, blood sugar levels dropped to match those of the control mice. The researchers noted similar associations between sweetener consumption, microbial changes, and glucose metabolism in a group of seven human volunteers in a one-week study. Previous studies have shown that dietary changes can alter gut microbe composition and function. In addition, human health and nutrition studies have shown that using artificial sweeteners to limit calories has not curbed the global prevalence of obesity. The researchers say their results raise new questions about the benefits versus safety of consuming artificial sweeteners.—SR
2014, DOI: 10.1039/c4sc01626b). Adding an (S)-hydroxyaminobutyric acid to neomycin’s B-ring and fluorinating it was also effective (ACS Chem. Biol. 2014, DOI: 10.1021/ cb5003416). To see how fluorine made a difference, Hanessian’s team used X-ray crystallography. Aminoglycosides interfere with bacterial protein synthesis by binding tightly to a microbe’s ribosomal RNA in a position called the A-site. The crystal structure shows that axial fluorine contacts a guanine nucleic acid in the A-site.—CD
CHINESE HAZE SOURCES IDENTIFIED Air pollution leading to dense haze in Chinese cities is driven by formation of aerosol particles in the atmosphere stemming from a variety of organic and inorganic precursor materials, according to a report (Nature
Scientists have identified another molecule that boosts the ability of umbilical cord blood to produce hematopoietic stem cells—cells that have the potential to beElemental carbon Unidentified come any type of blood cell in the body (Sci3% 10% ence 2014, DOI: 10.1126/science.1256337). Chloride 4% With further research, the discovery Trace Organic could offer a solution for the 30 to 40% of elements matter 4% 41% people who need bone marrow transplants Ammonium but are unable to find a matched donor. 10% FLUORINE FIX FOR Transplanted stem cells from cord blood Nitrate are readily accepted by people, but they’re WEAKENING ANTIBIOTICS 12% Sulfate not produced in a sufficient quantity to 16% be useful in adults. Scientists have been A strategically placed fluorine today could Composition of airborne particles in Beijing searching for small molecules that boost keep antibiotic resistance at bay. Aminoglycord blood stem-cell production in lab cell cosides are a class of antibiotics that have 2014, DOI: 10.1038/nature13774). The recultures. A Canadian and American team traditionally been useful against infections sults suggest that reducing health-harming led by Guy Sauvageau in patients with severe burns or cystic fibroparticulate matter—the Chinese State N of the University sis. Antibiotic-resistant bacteria Council’s goal is to get to 75% of 2012 levels N H C N H of Montreal now 3 have emerged, however, carrying by 2017—will require control of the precurN N describes a pyan arsenal of aminoglycosidesors. The study, which was led by Jun-Ji Cao N rimidoindole called UM171, inactivating enzymes. One apof the Chinese Academy of Sciences and which they screened from a proach to counter the enzymes has André S. H. Prévôt of Switzerland’s Paul N HN library of 5,280 compounds, that been to remove certain aminoglycoside Scherrer Institute, looked at the composiincreases hematopoietic stem cells hydroxyl groups. But that change can make tion of atmospheric particles in Beijing, 13-fold in cord blood samples. UM171 the drugs toxic to the kidneys. Stephen Shanghai, Guangzhou, and Xi’an in January also appears to increase production Hanessian and colleagues at the University 2013. Excluding dust, the researchers found of stem-cell precursor cells more that a majority of particles with a diameter NH2 of Montreal instead tinkered with neoUM171 than a previously described cord mycin B, an aminoglycoside and the acless than 2.5 µm are formed in the atmoblood booster named SR1. The researchers tive ingredient in popular over-thesphere rather than being emitted directly. NH2 F found that UM171 remains effective for up counter antibiotic ointments, to As in urban settings elsewhere in the to 30 weeks when used in transplants in see whether fluorination might world, reducing airborne particulate O immunocompromised mice.—EKW help. When Hanessian’s team matter in China will thereHO H2N replaced the 4´-hydroxyl group fore require not just H2N O HO NH2 controlling primary on neomycin’s A-ring with O O OH ARTIFICIAL SWEETENERS an axial fluorine (shown), emissions but also HO H N particle precursors such as 2 BOOST GLUCOSE LEVELS they created an analog that evades aminoglySO2, NOx, and volatile organic carbon O OH O A preliminary study on the metabolism coside-inactivating compounds released by fossil-fuel and H2N OH of artificial sweeteners has found that the enzymes in bacterial biomass burning, the study’s compounds may alter the types and funccell cultures (Chem. Sci. Fluorinated neomycin analog authors note.—JK CEN.ACS.ORG
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