This is the twice-per-month electronic newsletter for basic, preclinical and translational research news related to the Johns Hopkins School of Medicine. Please forward freely. Direct comments or questions to Joanna Downer, PhD, in the Office of Corporate Communications (410-614-5105, jdowner1@jhmi.edu).
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*** Basic Science Town Meeting June 30 at 2 pm ***
IN THIS ISSUE:
RESEARCH HIGHLIGHTS:
+ Biology Overcomes Cells' Physical Limitations
+ Different Microarray Systems More Alike Than Previously Thought
+ "Dual Action" Protein Links Nerves' Guidance and Calcium Influx
NEWS BRIEFS:
Hopkins Alums To Speak June 3
Rothstein, Feinberg on Calif. Stem Cell Committee
Basic Science Town Meeting June 30
HONORS AND AWARDS:
Talalay Wins Pauling Prize
IN THE NEWS:
Conover Talbot, Jr., in The Palm Beach Post
Obituary for Kenneth Johnson in The Baltimore Sun
John Gearhart and Ruth Faden in the New York Times
Kathy Hudson in the San Francisco Chronicle
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Do you have an interesting research finding about one month from publication or presentation? Send manuscripts to Joanna Downer at jdowner1@jhmi.edu or fax to 410-614-8951. Information about awards and honors received by laboratory personnel and others is welcomed also.
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RESEARCH HIGHLIGHTS:
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5/17/05
Biology Overcomes Cells' Physical Limitations
Using amoeba as their model system, a pair of scientists has discovered clear evidence that a cell's normal biology helps it overcome the physical laws that would otherwise dictate its behavior during cell division. The findings are published in the May 17 issue of the Proceedings of the National Academy of Sciences.
Johns Hopkins biologist Douglas Robinson, PhD, and University of Chicago physicist Wendy Zhang, PhD, compared the cells' behavior during cell division, or cytokinesis, to what would happen in a purely physical system, such as a similarly shaped sticky fluid like honey.
"We found that, under normal circumstances, the amoeba divide a hundred times slower than if they were a simple fluid, which was a surprisingly large difference," says Robinson, professor of cell biology in Hopkins' Institute for Basic Biomedical Sciences and in whose lab the work was done. "But the cell may have developed its control mechanism to give it time to reduce errors and limit cell growth."
The amoeba divide not simply by pinching off through the middle, but by elongating and then forming a barbell-shaped intermediate, which is later cleaved in two. The researchers found that, at all stages of cell division, the amoeba's biology counteracts the physical force that dictates whether liquids stay in a ball-like shape, elongate or split in two -- a force known as the Laplace pressure.
Until the "bar" forms in dividing amoeba, a centrally located protein called myosin II pushes cell division forward, helping to constrict the center of the cell and enable the barbell shape, the researchers found. Once the barbell shape has been reached, proteins found at the cell's periphery, including the protein dynacortin, push against the cell's natural tendency to split in two, slowing down the process.
PNAS 17 May 2005;102(20):7186-7191.
http://www.pnas.org/cgi/content/full/102/20/7186
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5/23/05
Different Microarray Systems More Alike Than Previously Thought
A multicenter comparison of microarray platforms suggests these different technologies are more alike than once thought.
Described in the May 2005 issue of Nature Methods, the study provides new hope that the mounds of information generated by these systems might actually be comparable, even though many different systems are used by many different laboratories.
"Given the amount of tinkering that occurs in some labs, my intuition was that different labs might obtain very different answers even when using the same platform," said Rafael Irizarry, PhD, associate professor of biostatistics at the Johns Hopkins Bloomberg School of Public Health. "But we show that platforms can agree rather well, and that there is a large lab effect that accounts for why others thought comparisons revealed inconsistencies."
For the study, 10 laboratories in the Baltimore/Washington area were given identical samples of RNA to analyze using a microarray platform of their choice. Five labs used Affymetrix GeneChips, three used in-house two-color spotted cDNA arrays, and two used another commercial platform, so-called two-color long oligonucleotide arrays.
With the exception of one lab, the results among platforms were in general agreement, and the quality of expensive and inexpensive platforms was similar across the board.
"Given appropriate and careful analysis, it should be possible to compare historical data to future experiments, even if the technology changes or people make different choices in their platform," says Forrest Spencer, PhD, associate professor at Johns Hopkins' McKusick-Nathans Institute of Genetic Medicine.
http://www.hopkinsmedicine.org/Press_releases/2005/05_23_05.html
Nature Methods 2005;2:345-350.
http://www.nature.com/nmeth/journal/v2/n5/abs/nmeth756.html
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5/31/05
"Dual Action" Protein Links Nerves' Guidance and Calcium Influx
By studying nerves in developing frogs, researchers from Johns Hopkins' Institute for Cell Engineering have uncovered a link between two key players needed to direct nerves toward their appropriate targets.
The importance of the two known players -- guidance cues that somehow attract or repel the tip of the growing nerve, and an influx of charged calcium ions and/or release of calcium ions from the cell's internal stores -- has long been recognized, but how the guidance cues might trigger influx or release of calcium ions hasn't been known.
"For 20 years researchers have known that calcium flow is critical for proper nerve growth, but no one has known how it gets into the nerve in response to a guidance cue, and no one has been able to identify the relative contributions of calcium coming from outside the cell versus calcium coming from the cell's internal stores," says Guo-Li Ming, PhD, assistant professor of neurology in the Institute for Cell Engineering's Neuroregeneration and Repair Program.
The researchers have discovered that a protein called TRPC1, or transient receptor potential channel 1, lets calcium into the nerve's growing tip once triggered by certain guidance cues. In developing frogs, the protein's activity is required for a certain set of nerves in the spinal cord to grow properly.
The findings, described in the June issue of Nature Neuroscience, identify a brand new "dual action" class of contributors to proper nerve growth and regrowth in living creatures, says coauthor Hongjun Song, PhD, also assistant professor of neurology in ICE's neuroregeneration program. TRP channels were first identified by Craig Montell, professor of biological chemistry and neuroscience at Johns Hopkins, and are known to be cellular sensors for heat and pain.
Nature Neuroscience June 2005;8(6):730-735.
http://www.nature.com/neuro/journal/v8/n6/full/nn1459.html
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NEWS BRIEFS:
Hopkins Alums To Speak June 3 -- Johns Hopkins School of Medicine alumni Stephen Desiderio (MD '81, PhD '81), Kenneth Berns (MD '66, PhD '64), Charles Sawyers (MD '85), and Min Li (PhD '91) will give talks Friday, June 3, starting at 8:45 a.m. in the Wood Basic Science Auditorium. Desiderio will be the first to speak, and his 30 minute talk is titled "The Basic Sciences at Johns Hopkins: Perspectives for Growth." Berns will follow at 9:15 a.m. on "Adeno-Associated Virus: From Laboratory Curiosity to Therapeutic Agent." Sawyers, a Howard Hughes investigator at the University of California at Los Angeles, will give a 10 a.m. talk titled "Kinase Inhibitors in Cancer Treatment." Li will wrap up the morning's lectures by speaking on "Membrane Excitability -- Potassium Channels in Health and Disease."
Rothstein, Feinberg on Calif. Stem Cell Committee -- Two Johns Hopkins University School of Medicine researchers are among 15 nationally known scientists chosen to evaluate and select stem cell research projects to be funded by the California Institute for Regenerative Medicine (CIRM), created when the state's voters passed Proposition 71 authorizing CIRM last fall. Johns Hopkins researchers Andrew Feinberg, MD, MPH, an expert in epigenetics, and Jeffrey Rothstein, MD, PhD, an expert on Lou Gehrig's disease, will serve six-year terms on the evaluation committee, known officially as the Scientific and Medical Research Funding Working Group.
http://www.hopkinsmedicine.org/Press_releases/2005/05_20a_05.html
Basic Science Town Meeting June 30 -- The next Basic Science Town Meeting will be Thursday, June 30, at 2 p.m. in Preclinical Teaching Building Room 517.
Talalay Wins Pauling Prize -- On Wednesday, May 18, Johns Hopkins scientist Paul Talalay, MD, was awarded the 2005 Linus Pauling Institute Prize for Health Research and delivered a plenary lecture during the first day of an international conference on diet and optimum health in Portland, organized by the Linus Pauling Institute at Oregon State University. Talalay, the John Jacob Abel Distinguished Service Professor of Pharmacology, and director of the Laboratory for Molecular Pharmacology at The Johns Hopkins University School of Medicine, is a pioneer in the study of dietary phytochemicals that help protect against cancer. The award, which includes a medal and $50,000 honorarium, is a leading honor for scientists studying micronutrients, diet and other natural approaches to disease prevention or therapy. http://www.hopkinsmedicine.org/Press_releases/2005/05_18_05.html
IN THE NEWS:
Conover Talbot, Jr., on naming genes in The Palm Beach Post. "Scientists get the lab laugh with amusing gene names," by Stacey Singer, the Palm Beach Post, May 15, 2005.
http://www.jhu.edu/clips/2005_05/16/get.html
(Must be at a Hopkins computer to access this page.)
Obituary for Kenneth Johnson in The Baltimore Sun. "Kenneth O. Johnson, 66, Hopkins neuroscientist," by Gus G. Sentementes, the Baltimore Sun, May 15, 2005.
http://www.jhu.edu/clips/2005_05/16/kenneth.html
(Must be at a Hopkins computer to access this page.)
John Gearhart and Ruth Faden on South Korean stem cell advance in the New York Times. "Koreans Report Ease in Cloning for Stem Cells," by Gina Kolata, The New York Times, May 20, 2005.
http://www.jhu.edu/clips/2005_05/20/koreans.html
(Must be at a Hopkins computer to access this page.)
Kathy Hudson on South Korean stem cell advance in the San Francisco Chronicle. "New Stem Cell Lines Created by Cloning," by Carl T. Hall, The San Francisco Chronicle, May 20, 2005.
http://www.jhu.edu/clips/2005_05/20/newstem.html
(Must be at a Hopkins computer to access this page.)
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John Sales contributed to the Research Highlights for this issue.
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--JHMI--
