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Dscam Reveals its Bountiful Plan

By | June 21, 2004

Courtesy of Dietmar SchumuckerI got this cDNA sequence alignment for the Dscam gene in October 1999 while working in Larry Zipursky's lab. The gap in the alignment hinted at alternative splicing of the transmembrane domain. But that was just the tip of the iceberg: The handwritten inset is from my notes indicating not only this successful sequencing reaction but also that two reactions failed – much to my frustration (see the question marks). It turned out, however, that this was good news


Finding the Achilles' Heel of AIDS

By | June 7, 2004

Courtesy of the Michael H. Malim LabFor about 10 years, our laboratory had been trying to elucidate why the HIV Vif protein is essential for virus replication. Since 1998, we had suspected that Vif 's role was to inhibit a cellular protein that naturally blocks infection. This scintillation counter printout from December 2001 shows that varying amounts of a candidate inhibitor gene we had identified, called APOBEC3G/CEM15, profoundly suppress infection (measured as radioactivity in the CPM colum


An Early Look at a Killer

By | May 24, 2004

Reprinted from T.D. Brock, Robert Koch: A Life in Medicine and Bacteriology, Science Tech Publishers: Madison, WI, 1988, pg. 51, Fig 6.5Robert Koch (1843–1910) was a country doctor from the German hinterlands of what is now Poland. He liked to investigate samples from his barnyard animals under a microscope. He went on to become the world's first and one of its greatest bacteriologists, winning the Nobel Prize in 1905. Although famed for his work on tuberculosis and the postulates named af


A New Pathway for Inositol

By | May 10, 2004

Courtesy of Cantley labIn the mid 1980s we discovered a phosphatidylinositol kinase that co-purified with several oncoproteins and that correlated with cell transformation. When my graduate student Malcolm Whitman presented his results at a lab meeting, I noticed that in this autorad, the phosphatidylinositol phosphate produced by the oncoprotein-associated PI kinase (Type I) migrated slightly more slowly in thin layer chromatography (TLC) than that produced by PI 4-kinase (Type II).The reproduc


The Day the Earth Stood Still

By | April 26, 2004

Courtesy of Harry Ransom Center, U of Texas at AustinThere are many milestones on the road to modern science, but few equal the summer afternoon in 1826 when French inventor Joseph Nicephore Niepce (1765–1833) captured the first permanent image. Niepce, a tinkerer and amateur scientist, set out to automate the lithography process in 1812. Experiments with various acids and other substances failed. Still tinkering 15 years later, he set up a pewter plate layered with photosensitive bitumen


Defining DNA as the Hereditary Molecule

By | April 12, 2004

Waring BlenderCourtesy, Sue Lauter, Cold Spring HarborIn 1952, Alfred Hershey of Cold Spring Harbor Laboratory and his lab technician, Martha Chase, wanted to confirm that DNA was the carrier of genetic information. They tagged the protein coating of bacteriophages with the sulfur isotope 35S and the DNA core with the phosphorus isotope 32P. Using a Waring blender, they agitated the viral particles and bacteria. The blender caused the viruses to shear off the outside of the bacteria: The tagged


Rediscovering Heat Shock Proteins

By | March 29, 2004

Courtesy of Pramod SrivastavaOften in science, what seem to be definitive answers lead to new questions, which lead to new answers and the cycle goes on. That's what happened when I came across heat shock proteins. I was a postdoc at Sloan Kettering in 1985, and I had just received the results of the N-terminal sequence of gp96, a tumor-rejection antigen, which I had purified from a mouse sarcoma, and earlier from a rat hepatoma. With the sequence in hand, I felt confident that I had just solved


On the Trail of BRCA1

By | March 15, 2004

Courtesy of Mary-Claire KingAfter 16 years of exhausting research, data collection and computation, Mary-Claire King's lab determined in 1990 that a mutation on chromosome 17 was a common occurrence among women in families that had clusters of breast cancer. This family tree shows one of the families in the study. Squares are men, circles are women. Blackened circles indicate women with breast cancer. A cross through the symbol means that person died.When the paper was published in 1990,1 King b


Climbing the Molecular Stairway

By | March 1, 2004

Courtesy of Steven BlockIt had long been assumed that motor proteins would advance in discrete steps. However, the steps posed a challenge for measurement because they were small enough to be comparable to the background noise due to the Brownian (thermal) motion. During 1993, together with graduate student Karel Svoboda, postdoc Christoph Schmidt, and kinesin codiscoverer Bruce Schnapp, I set out to show that kinesin moved in a stepwise fashion along microtubules, and to measure the size of tho


A Very Tiny Encounter

By | February 16, 2004

Courtesy of David McKay, NASAIt weighs only 1.9 kilograms and is an estimated 4.5 billion years old. Yet the ALH84001 meteorite is probably the most argued-about rock in the universe (or at least in our solar system.) The anonymous member of an Antarctic geological field survey who found the rock in 1984 wrote in the field ticket's margins, "Yawza yawza!" Twenty years later, scientists are still making exclamations about the rock's innards. Some suspect that the ghostly forms in this scanning el


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