:: By Lydialyle Gibson

:: Photo by Dan Dry

Investigations ::

Cancer repair

Scientists have deciphered the molecular structures of two proteins that repair damaged cancer cells, raising the possibility of creating a substance that could make chemotherapy more effective by disrupting cancer-cell repair. The bacterial protein AlkB and a related human protein, ABH2, bind to a tumor’s DNA to mend lesions caused by alkylating treatments, which are among the most commonly used in chemotherapy. Alkylating agents target cancer cells’ genetic material, causing cross-linked DNA strands, abnormal base pairing, or breaks in the DNA strand—all of which prevent the cells from dividing. In the April 24 Nature Chicago researchers, led by chemist Chuan He, described AlkB and ABH2’s three-dimensional framework and their interactions with malignant cells.

New wrinkle in membrane study

Chemists Ka Yee Lee and Luka Pocivavsek scrutinize the wrinkles in a polyester film.

Unlike paper, which, when crumpled and flattened, retains permanent creases, microscopically thin membranes wrinkle and then fold—and, after the crumpling stops, flatten out smoothly. In the May 16 Science, U of C chemist Ka Yee Lee and MD/PhD student Luka Pocivavsek, SM’04, explained the physics governing how lung surfactant, a two-nanometer-thick membrane that aids breathing, behaves under compression. When people exhale, lung surfactant constricts, wrinkling at first and then transitioning to folds—peaks and troughs. With inhalation, the membrane stretches back flat. Lee, Pocivavsek, and their collaborators devised a set of experiments using a ten-micron-thick polyester film and three-layer gold nanoparticles to scrutinize the wrinkling-to-folding transition. Their findings could be used both to design foldable electronics and to develop therapies for those with respiratory-distress syndrome, a breathing problem caused by insufficient lung surfactant.

ACT prep flunks 

All those hours of intense preparation for the ACT may be a waste of students’ time—or worse. A three-year study released May 27 by the University-based Consortium on Chicago School Research linked significant class time spent on test drills to lower scores. Instead of test-prep, the researchers argue, teachers should concentrate on bolstering students’ knowledge of test subjects. Headed by Consortium codirector Elaine Allensworth, the study found that Chicago public-school teachers commonly spend a month of classroom time, spread out over a year, helping students cram for the exam, which Illinois requires all juniors to take. Eighty-three percent of the city’s 11th graders believe, erroneously, that their scores depend mostly on test-taking skills. In fact, the strongest predictor of high ACT scores is good grades in core courses like English, math, and science.

Riddle of the sphinx gene

Chicago scientists have found that a specific fruit-fly gene, when suppressed in males, leads the insects to court other males. Along with researchers in his lab, ecology & evolution professor Manyuan Long discovered the gene in 2002. Because its chimeric structure draws nucleotides from different parts of the genome, the team named the gene “sphinx” after the famous chimera from Greek mythology. Unique to fruit flies, it evolved within the past 2 to 3 million years. Males with functioning sphinx genes pursue other males, but rarely and only briefly. Long’s team found that with sphinx genes inactivated, males pursued each other routinely and persistently, progressing through an elaborate mating ritual that includes orienting, tapping, singing, and licking. Unable to copulate, though, they returned to female flies. Published in the May 27 Proceedings of the National Academy of Sciences, the study was coauthored by Hongzheng Dai, PhD’07, and Ying Chen, PhD’08.