SCIENCE & TECHNOLOGY
from the SCENEs A selection of stories from C&EN’s six online TOPICAL NEWS CHANNELS
PEPTIDE-DRUG CONJUGATE KILLS PERSISTENT BACTERIA To evade antibiotics, some pathogenic bacteria ramp down their metabolic activity and block the drugs from slipping through their membranes. These persistent microbes can cause chronic infections in patients. Now, researchers have linked a cell-penetrating peptide to an established antibiotic so the drug can enter persistent bacteria, killing them more effectively than the antibiotic alone (ACS Nano 2014, DOI:
FROM THE ENVIRONMENTAL SCENE
RECOVERING PHOSPHORUS FROM ANIMAL MANURE
10.1021/nn502201a). Gerard C. L. Wong 1 million times as potent against S. aureus and Andrea M. Kasko of the University of ones. Because developing new antibiotics California, Los Angeles, and colleagues is costly, Wong and Kasko hope this condesigned a 12-amino-acid peptide that can jugate strategy can work to ramp up the disrupt cell membranes and attached it potency of other existing antibiotics. to the aminoglycoside antibiotic toO Cell-penetrating peptide bramycin, which blocks the ribosome O N from carrying out protein translation. H O They then compared the ability of the new molecule, pentobra, to kill O H2 N OH HO persistent strains of Escherichia coli O H2N NH2 OH and Staphylococcus aureus with that of HO O O tobramycin. The modified antibiotic NH2 H2N was up to 10,000 times as potent toPentobra ward persistent E. coli cells and up to
FROM THE ANALYTICAL SCENE
of Minnesota, Twin Cities, wanted to use a method that required less energy. To test hydrothermal carbonization on animal waste, he and his colleagues suspended manure from cows, pigs, or chickens in water and heated the slurry to between 200 and 250 °C in a closed
Phosphorus is an essential nutrient in agriculture. Some scientists worry that the demands of the world’s growing population will overwhelm natural supplies of the element. One team looking for a sustainable source of phosphorus now reports that they can recover 80 to 90% of the element from animal manure through a method called hydrothermal carbonization (Environ. Sci. Technol. 2014, DOI: 10.1021/ es501872k). Manure produced each year by large-scale farming operations in the U.S. contains Manure from livestock, container. They such as pigs, contains 2.7 billion lb of P2O5, the phostreated the resultphosphorus that can be ing hydrochar solid phorus form used in fertilizer. harvested and used as a with aqueous acid to Other researchers have tried fertilizer for food crops. to harvest phosphorus from dissolve metal phossewage sludge by incinerating phate salts and then it and processing the resulting ash. But added base to precipitate predomiSteven M. Heilmann of the University nantly calcium phosphate.
HIGHLIGHTING TUMORS DURING BRAIN SURGERY
SHUTTERSTOCK
FROM THE BIOLOGICAL SCENE
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SEPTEMBER 15, 2014
Using a handheld Raman scanner and nanosized contrast agents, surgeons operating on mice have detected and removed clusters of brain cancer cells not visible to the naked eye (ACS Nano 2014, DOI: 10.1021/nn503948b). If the contrast agent is proven safe for use in people, the technique could help doctors do a more thorough job of removing brain tumors and improve patient survival. The 120-nmdiameter contrast agent is a spherical gold particle coated with a Raman-active dye and wrapped in a protective silica crust. Moritz F. Kircher, a radiologist at Memorial Sloan Kettering Cancer Center, and colleagues previously demonstrated in mice that a similar nanoparticle accumulates in brain tumors called glioblastomas and that it can help visualize the tumors under a Raman microscope. They wanted to see whether the contrast agent would also work with a handheld Raman scanner—a device resembling a laser pointer that is operating-room friendly. After neurosurgeons operated on mice using the contrast agents and handheld scanner, the team found no detectable cancer cells in the animals’ brains. When the surgeons used standard techniques, cancer cells remained.
