Lovett, alumni named AAAS Fellows

Professor of Biology Susan T. Lovett was elected a fellow of the American Association for the Advancement of Science. AAAS fellows will be recognized for their contributions to science and technology on 16 February 2013 during the AAAS Annual Meeting in Boston. Brandeis alumni elected as fellows are Steve Alexander (PhD ’76), Patrick Casey (PhD ’86), Rui-Ming Xu (PhD ’90) and Charles Brenner (postdoc 93-96).

Lovett, who works on DNA repair mechanisms in bacteria, has recently been profiled on Brandeis NOW.

NSAID gels and COX-2 selectivity in topical pain killers

Research from Bing Xu’s lab, published in November in Journal of the American Chemical Society, has recently been featured in C&E News. The Xu lab researchers, including Chemistry grad students Jiayang Li, Yi Kuang, Yuan Gao, Xuewen Du and Junfeng Shi, synthesized hydrogels by synthetically coupling small D-amino acid peptides to naproxen (a non-steroidal antiinflammatory drug – NSAID). This was done with the idea of forming gels that can be used for topical pain treatment.

Studies on the compounds formed showed that not only are gels formed, but the D-peptide conjugates of naproxen showed better selectivity towards COX-2 (the therapeutic target) compared to COX-1 (a source of side effects) than naproxen alone or an L-peptide conjugate. Clinical applications are still far away, but this finding opens exciting new avenues for research.

Li J, Kuang Y, Gao Y, Du X, Shi J, Xu B. d-Amino Acids Boost the Selectivity and Confer Supramolecular Hydrogels of a Nonsteroidal Anti-Inflammatory Drug (NSAID). J Am Chem Soc. 2012.

Med School and Grad School in the Lone Star State

Wensink lab alum Mien-Chie Hung (PhD ’84), who is currently Ruth Legett Jones Distinguished Chair at  The University of Texas MD Anderson Cancer Center, will give seminar on Monday, Dec 3 at noon in Rosenstiel 118 on “Novel signaling pathways in cancer cells and their crosstalk to predict resistance for target therapy“.  He will also meet with interested students on Monday Dec. 3 in the Alumni Lounge in Usdan at 7 PM; there will be pizza.   He will talk with undergrads, prospective grad and med students about medical schools and graduate schools in Texas Medical Center including MD Anderson, UT Health Science Center and Baylor.

Pieter Wensink (1941-2012)

Professor Jim Haber presented the following memorial tribute at Faculty Meeting on Nov 8, 2012:

Professor Emeritus Pieter Croissant Wensink passed away on October 2, 2012 in Wellesley, MA. Pieter was born in Washington, DC, in 1941, and grew up in Bethesda and Chevy Chase, MD. He attended Lawrence College in Appleton, WI, but like many young people in the 60s, dropped out. He ended up working in a laboratory at Johns Hopkins, where he discovered a passion for science. He never got his BA, but by taking night courses Pieter got himself accepted as a graduate student at Johns Hopkins, where he received his PhD in Biology in 1971, working with Don Brown, a pioneer in studying the regulation of gene expression in frogs. Pieter then went to Stanford, where he did post-doctoral work with David Hogness. At Stanford, Pieter got in on the ground floor of the new recombinant DNA technology. He published, with Hogness, a landmark paper entitled “A system for mapping DNA sequences in the chromosomes of Drosophila melanogaster” – the fruit fly.

In 1975 Pieter came to Brandeis as an Assistant Professor in the Rosenstiel Center and in the Department of Biochemistry, bringing to Boston the then-rare and prized knowledge of how to clone genes. I remember clearly in 1976 when an MIT professor, David Botstein, and his postdoc, Tom Petes, camped out at Brandeis for several weeks learning from Pieter how to clone yeast genes. Their collaboration resulted in another major paper “Isolation and analysis of recombinant DNA molecules containing yeast DNA.” Soon thereafter Matthew Mesleson arrived from Harvard, to collaborate with Pieter on the “Sequence organization and transcription at two heat-shock loci in Drosophila.” All of these papers were pioneering works.

Pieter also taught these “dark arts” to the people in my lab and launched us and others at Brandeis on the way to understanding the mysteries of chromosome architecture and gene regulation. In 1981 Pieter also wrote a book in collaboration with his Biochemistry colleague Bob Schleif: Practical Methods in Molecular Biology.

Pieter’s own work, carried out with a series of superb graduate students, focused on genes that encode the proteins that make up the yolk of Drosophila eggs. The study of these genes revealed the complicated way that yolk protein genes are turned on only in females and only in their ovaries. Many of Pieter’s students are now Professors in their own right at major universities around the country.

In the early 1990s Pieter was diagnosed with a benign brain tumor – a meningioma – that required two surgeries to extirpate. Probably his tumor was the result of the now-impossible-to-believe treatment of a ringworm infection with X-rays when he was about 2 years old. The second operation left him unable to concentrate as he had, and Pieter, sadly, decided that he could no longer run his lab or give the clear lectures had had been offering. So he left Brandeis as an emeritus Professor with a medical disability. Pieter was remarkably calm and accepting about his situation. He decided to pursue a long-deferred passion to paint, and some years ago he earned his BFA with distinction in painting from the Massachuetts College of Art. Altogether, Pieter had 5 operations on the cancers that led to his death.

Pieter’s greatest joy in life was his family. He was married to Dorothy E. (Perry) for 43 years and was the devoted father of Tom, Alan and Joe (who recently earned his PhD in English from Brandeis).

Most of you never met Pieter, so I thought it would be good to see Pieter and some of his colleagues as we looked in the late1970s (Pieter, Michael Rosbash, Marion Nestle (now oft-interviewed nutritionist at NYU), myself, and David DeRosier). And to see two of his paintings. He was a fine man.


Record-Setting X-ray Jet Discovered

X-ray jet

X-ray jet from quasar GB 1428, located 12.4 billion light years from Earth. (X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA)

On November 28, NASA posted a press release announcing the record breaking discovery of an x-ray emitting jet in a quasar at a distance of 12.4 billion light years from Earth. The discovery is published in the Astrophysical Journal Letters, and the lead author is C. (Teddy) Cheung (Brandeis PhD 2004). Co-authors include Doug Gobeille (Brandeis PhD 2011), Brandeis professor of astrophysics John Wardle, and colleagues from the Harvard-Smithsonian Center for Astrophysics. Teddy Cheung made the x-ray image, using the orbiting Chandra X-ray observatory, and Doug Gobeille made the radio image as part of his PhD research at Brandeis using the 27 antennas of the Very Large Array in New Mexico.

A jet of X-ray emitting plasma from a supermassive black hole 12.4 billion light years from Earth has been detected by NASA’s Chandra X-ray Observatory. This is the most distant X-ray jet ever observed and gives astronomers a glimpse into the explosive activity associated with the growth of supermassive black holes in the early universe. The jet was produced by a quasar named GB 1428+4217, or GB 1428 for short. Giant black holes at the centers of galaxies can pull in matter at a rapid rate producing the quasar phenomenon. The energy released as particles fall toward the black hole generates intense radiation and powerful beams of high-energy particles that blast away from the black hole at nearly the speed of light. These particle beams can interact with magnetic fields or ambient photons to produce jets of radiation.

“We’re excited about this result not just because it’s a record holder, but because very few X-ray jets are known in the early universe,” said Teddy Cheung of the National Academy of Sciences, resident at the Naval Research Laboratory in Washington DC, and lead author of the paper describing these results.

As the electrons in the jet fly away from the quasar, they move through a sea of background photons left behind after the Big Bang. When a fast-moving electron collides with one of these so-called cosmic microwave background photons, it can boost the photon’s energy into the X-ray band.

“Since the brightness of the jet in X-rays depends, among other things, on how fast the electrons are moving away from the black hole, discoveries like the jet in GB 1428 tell us something about the environment around supermassive black holes and their host galaxies not that long after the Big Bang,” said co-author Lukasz Stawarz from the Japan Aerospace Exploration Agency, in Kanagawa, Japan.

Because the quasar is seen when the universe is at an age of about 1.3 billion years, less than 10% of its current value, the cosmic background radiation is a thousand times more intense than it is now. This makes the jet much brighter, and compensates in part for the dimming due to distance.

“We’re lucky that the universe gives us this natural amplifier and lets us detect this object with relatively short exposures,” said co-author Aneta Siemiginowska, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, “Otherwise we might miss important physical processes happening at very large distances from Earth and as far away as GB 1428.”

While there is another possible source of X-rays for the jet — radiation from electrons spiraling around magnetic field lines in the jet — the authors favor the idea that the cosmic background radiation is being boosted because the jet is so bright.

Prior to the discovery of the jet in GB 1428, the most distant X-ray jet known was 12.2 billion light years away, and another is located at about 12 billion light years, both discovered by authors of the GB 1428 paper. A very similar shaped jet in GB 1428 was also detected in radio waves with the NSF’s Very Large Array (VLA).

The particle beams that produce these three extremely distant X-ray jets appear to be moving slightly more slowly than jets from galaxies that are not as far away. This may be because the jets were less energetic when launched from the black hole or because they are slowed down more by their environment.

The researchers think the length of the jet in GB 1428 is at least 230,000 light years, or about twice the diameter of the entire Milky Way galaxy. This jet is only seen on one side of the quasar in the Chandra and VLA data. When combined with previously obtained evidence, this suggests the jet is pointed almost directly toward us. This configuration would boost the X-ray and radio signals for the observed jet and diminish those for a jet presumably pointed in the opposite direction.

Observations were also taken of GB 1428 with a set of radio telescopes at different locations around the Earth that allows details to be resolved on exceptionally small scales. They revealed the presence of a much smaller jet, about 1,900 light years long, which points in a similar direction to the X-ray jet.

This result appeared in the September 1st, 2012 issue of The Astrophysical Journal Letters. Other co-authors of the paper are Doug Gobeille from University of South Florida in Tampa, FL; John Wardle from Brandeis University in Waltham, MA; and Dan Harris and Dan Schwartz from the Harvard-Smithsonian Center for Astrophysics.

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra Program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

More information, including images and other multimedia, can be found at:

Deciding the fate of a stalled RNA polymerase

Ever wondered what happens when the transcription machinery runs into a DNA lesion or a protein roadblock? Alexandra M. Deaconescu, corresponding author and research associate in the Grigorieff laboratory together with HHMI Investigator and Biochemistry Professor Dr. Nikolaus Grigorieff and Dr. Irina Artsimovitch (Ohio State University) address this question in a new review “Interplay of DNA repair with transcription: from structures to mechanisms” featured in the latest issue of Trends in Biochemical Sciences. The review describes emerging mechanisms of transcription-coupled DNA repair with emphasis on the bacterial system.

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