Tuesday, March 02, 2010

Scientiae Carnival @ A Lady Scientist

Amanda at A Lady Scientist has posted the March Scientiae Carnival.

This month's theme is "continuity", as Amanda explains:

I chose this month's theme because it is constantly coming up in my life right now. I am hoping to graduate sometime this year. This has spurred a lot of talk in my lab and in my home about continuity. In the lab it tends to be in the form of sharing my knowledge and skills with Advisor and my fellow grad students. At home it's of the where will we live and what shall I do variety. With this in the forefront of my mind, I decided to make Continuity the theme of this month's Scientiae Carnival. It seems, from most everyone's posts, that we, as scientists, have very little continuity in our lives. However, sometimes the more things change, the more they stay the same.
 There are some excellent posts, so go check it out!

Wednesday, February 17, 2010

Neither gone nor forgotten

I know it's been months since I posted here, but the blog hasn't been forgotten.

I've been working on some needed updates to the web site's theme. It's still a work in progress so the blog (and site) may be down occasionally.

I'm also going to start updating the too-long-neglected list of women science bloggers. I'll be making the updates gradually over the next month or so, but feel free to drop me a note here if you'd like me to consider including your blog.

And if you are a blogger yourself, consider contributing to the March Scientiae Women in Science blog carnival, hosted this month by Amanda at A Lady Scientist. The theme is "continuity".

Thursday, October 08, 2009

National Medal of Science Winners

Yesterday President Barak Obama presented the National Medal of Science to nine "eminent researchers" and the National Medal of Technology and Innovation to four inventers, the "highest honors bestowed by the United States government on scientists, engineers, and inventors."

Three women were honored this year with the National Medal of Science.

Dr. Joanna Fowler, Senior Scientist at Brookhaven National Laboratory, New York

[. . . ] for her pioneering work in chemistry involving the synthesis of medical imaging compounds and her innovative applications of these compounds to human neuroscience, which have significantly advanced our understanding of the human brain and brain diseases, including drug addiction.

Dr. Elaine Fuchs
, Rebecca C. Lancefield Professor and Investigator, HHMI at the laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York
[. . .] for her pioneering use of cell biology and molecular genetics in mice to understand the basis of inherited diseases in humans and her outstanding contributions to our understandings of the biology of skin and its disorders, including her notable investigations of adult skin stem cells, cancers, and genetic syndromes.

Dr. JoAnne Stubbe, Novartis Professor of Chemistry and Professor of Biology, Massachusetts Institute of Technology
[. . . ] for her groundbreaking experiments establishing the mechanisms of ribonucleotide reductases, polyester synthases, and natural product DNA cleavers -- compelling demonstrations of the power of chemical investigations to solve problems in biology.

One woman was honored with the National Medal of Technology and Innovation:

Dr. Esther Sans Takeuchi, Greatbatch Professor of Advanced Power Sources in the Chemical and Biological Engineering Department, University at Buffalo, The State University of New York
[. . . ] for her seminal development of the silver vanadium oxide battery that powers the majority of the world's lifesaving implantable cardiac defibrillators, and her innovations in other medical battery technologies that improve the health and quality of life of millions of people.

Three women National Science Winners in a single year is a record high - and historically that number has frequently been zero. While that may seem like an encouraging upward trend, if you check the stats, more women were NMoS recipients in the 1990s (15) than in the 2000s (10). Hopefully, the 2010s will see an improvement in those numbers.

The National Medal of Technology and Innovation doesn't provide a way to search recipients by gender (and some winners are actually companies), but looking through the list it appears that Esther Sans Takeuchi is the first woman to win since Stephanie Kwolek in 1996.

Watch the awards ceremony on YouTube:

(President Obama also said some good things about supporting research and math and science education in his speech.)

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Wednesday, October 07, 2009

Another Day, Another Woman Wins a Nobel Prize for Nucleic Acid Biochemistry

On the Nobel Prize front, 2009 is turning into a banner year for both nucleic acid chemistry and women scientists. As I posted earlier this week, two of the three winners of the 2009 Nobel Prize in Medicine ("for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase") are women. And today it was announced that the Nobel Prize in Chemistry was awarded to Ada E. Yonath along with Venkatraman Ramakrishnan and Thomas A. Steitz "for studies of the structure and function of the ribosome."

The last woman to be awarded the Nobel Prize in Chemistry was Dorothy Hodgkin, who won the prize in 1964 for her advancement of the technique of X-ray crystallography for determining the structure of biomolecules such Vitamin B-12. Now, 45 years later, Ada Yonath has been recognized for her work determining the structure of ribosomes, using, once again, X-ray crystallography.

As most introductory biology texts diagram it, the "usual" flow of information in the cell1 goes from DNA, which is used as a template for the synthesis of messenger RNA (mRNA), which in turn is used as a template for the synthesis of proteins. Ribosomes are cellular organelles that mediate the third step, translation of the nucleic acid sequence into a the chain of amino acids that make up a protein.

10 small subunit.gif
By Animation by David S. Goodsell, RCSB Protein Data Bank - Molecule of the Month at the RCSB Protein Data Bank, Public Domain, Link
Ribosomes are usually depicted in textbooks as a large blob and a small blob, but their actual molecular structure is much more complex. Each blob, or subunit, is made up of RNA ("ribosomal RNA" or rRNA) and multiple proteins. The small ribosomal subunit shown at left, for example, is made up of 20 proteins (blue) and one RNA (orange), folded to form a complex 3-dimensional structure. (You can see more such structures on the Yonath Lab web site.)

As the Nobel Prize science backgrounder points out, determining the structure of ribosomes was an important technical achievement:

The ribosome, with its molecular weight of about 2.5 MDa is not only large but, unlike many virus particles, does not display symmetry properties that would facilitate crystallization and structure determination. In the years around 1980 it was therefore unclear whether crystals of the ribosome diffracting to high resolution (~3Å or less) could ever be found and, granted the existence of such crystals, whether the phase problem could be overcome and structures obtained. In this context, the report on three-dimensional crystals of the ribosomal 50S subunit from the thermophile bacterium Geobacillus (G.) stearothermophilus (previously called Bacillus stearothermophilus) in 1980 by Ada Yonath and colleagues (Yonath et al., 1980) was therefore a significant step forward.
Determining the detailed structure of ribosomes has been important in understanding the basic function of living cells. And it also has important clinical significance:
This knowledge can be put to a practical and immediate use; many of today's antibiotics cure various diseases by blocking the function of bacterial ribosomes. Without functional ribosomes, bacteria cannot survive. This is why ribosomes are such an important target for new antibiotics. This year's three Laureates have all generated 3D models that show how different antibiotics bind to the ribosome. These models are now used by scientists in order to develop new antibiotics, directly assisting the saving of lives and decreasing humanity's suffering.
Ada E. Yonath

Ada Yonath was born in 1939 to a poor Jewish family in Jerusalem. She was fascinated by science from an early age, and her family supported and encouraged her studies. As she recalled in 2008:
My father died when I was 11 years old and left my mother with me and my sister but no income, so I was needed at home. Nevertheless, my mother realized my lust for science and provided me with massive emotional support. She did not object to my academic studies, although at the time this was not so common for females. When I became a scientist, my mother, sister, and later on my daughter and granddaughter always supported my scientific activities, in my presence as well as in my frequent absences.
She also received encouragement in school from an early age:
Her elementary school math teacher Zvi Vinitzky introduced her to the principal of the elite Tel Aviv high school, Tichon Hahadash, Tony Halle. Impressed by the young girl's abilities, Halle admitted her to the school although she was not able to pay for the tuition. In repayment, Yonath tutored young Bulgarian immigrants in math.
After receiving her bachelor's degree in chemistry and master's degree in biochemistry from the Hebrew University of Jerusalem, she entered the laboratory of Wolfie Traub at the Weizmann Institute of Science in Rehovot, Israel. She earned her Ph.D. for X-ray crystallographic studies of collagen in 1968. After brief postdocs at Carnegie Mellon and MIT, she returned to the Weizmann Institute to establish the country's first protein crystallography laboratory in Israel.

Despite her expertise in X-ray crystallography, many scientists were skeptical that the technique could be used to determine ribosome structure, only they apparently didn't express it quite so tactfully.
[...] she was able to count on the support of "a few individuals, including several distinguished scientists and my own group of young and highly motivated students. They encouraged me even when my project met with rigorous skepticism from most prominent scientists all over the world, even when I was called 'a dreamer,' 'crazy' or the 'Village Fool.'"
Even her initial successes weren't immediately recognized by her colleagues:
[...] with the techniques then available, it took Yonath months of trying different solutions and crystallization procedures to get tiny crystals of the larger, or 50S, subunit of the ribosome from a Bacillus bacterium, and more than a year to get the first very fuzzy x-ray crystallographic images. But when she showed colleagues her results at an August 1980 meeting, "everyone laughed at me," Yonath recalls.
She eventually figured out that she needed to cryocool - freeze - the ribosomes to stabilize the crystals long enough clear data, a technique that is still in use today.

Since then Yonath has continued her research on ribosomal structure, both at the Weizmann Instute and at her parallal post as visiting professor and later the Head of a Max-Planck Research Unit in Hamburg, Germany. Her laboratory currently focuses on the interaction between ribosomes and antibiotics.

Yonath is also an advocate of encouraging other women to pursue careers in science:
"Women make up half the population," she says. "I think the population is losing half of the human brain power by not encouraging women to go into the sciences. Women can do great things if they are encouraged to do so."
"I would like women to have the opportunity to do what is interesting to them, to go after their curiosity. And I would like the world to be open to that. I know in many places there is opposition to that."2
A few key publications:

Additional links about Ada Yonath
1. That isn't quite accurate, because RNA can be reverse transcribed into DNA, DNA is duplicated when cells divide, and there are other ways that information flows within the cell. The key point is that the nucleic acid sequence can be converted into protein, but the sequence of amino acids in a protein can not be converted by the cell into a nucleic acid sequence. See Larry Moran's post on the Central Dogma for more.
2. It makes me a bit sad that that even needs to be said.

Bottom Image: Micheline Pelletier/Corbis. Check out more photos at the Nobel web site Photo Gallery
Top Image: "Animation of the small subunit of the Thermus thermophilus ribosome. RNA shown in orange, protein in blue." Taken from PDB 1FKA and animated by David S. Goodsell.
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Tuesday, October 06, 2009

Scientiae Carnival @ Mad Chemist Chick

Mad Chemist Chick has posted the October Scientiae blog carnival.
The theme was "The Road Not Taken":

This month's Carnival has contributions from bloggers who just begun their journeys while others have made the hard choices and are happy with their chosen paths. Still other bloggers are struggling with impending choices that could alter their paths forever.

Go read!

Monday, October 05, 2009

Blackburn and Greider win the Nobel for Medicine: the first time two women share the prize

Today it was announced that Elizabeth H. Blackburn, Carol W. Greider and Jack W. Szostak would share the 2009 Nobel Prize in Physiology or Medicine "for the discovery of how chromosomes are protected by telomeres and the enzyme telomerase". The award shouldn't have come as a surprise to anyone familiar with the modern biological sciences, since their work was indeed groundbreaking. It wasn't a matter of "if" they would win, but "when".

Telomeres are stretches of repetitive DNA that protect the ends of chromosomes during cell division - Blackburn has compared them to the tips on the ends of shoelaces1 that keep them from unraveling. As cells divide the telomere sequences get shorter and shorter, which limits cells to a fixed number of divisions. Telomere shorting is thought to be responsible for aging on a cellular level. Cancer cells, which divide indefinitely, carry mutations that allow the maintenance of telomere length.

You can find out more about the science by exploring the history of telomere research on the Lasker Awards site and by watching Blackburn's 2008 Women@GoogleTalk about telomeres and aging.

Some of the other awards won jointly by Blackburn and Greider:

Elizabeth Blackburn

Elizabeth Blackburn is a native of Hobart, Tasmania, Australia, the daughter of two physicians, a fact that Blackburn has noted helped shape her view of pursuing a career as a woman:

The main influence my parents' careers had on me was that it gave me the idea that women and men were equivalent in careers. They were both physicians, they grew up at the same time, and they trained at the same time. Probably, the other influence it had was showing me that motherhood and career can go together. My mother worked part-time much of the time, as I was one of seven children!

After receiving her B.Sc. and M.Sc. degrees from the University of Melbourne, she moved to the UK, where she earned her doctorate from the University of Cambridge in the laboratory of biochemist Frederick Sanger, who pioneered methods of nucleic acid sequencing. She moved to the United States in 1975 for postdoctoral work in the lab of Joseph G. Gall2 at Yale.

It was in Gall's laboratory that Blackburn analyzed the structure of the chromosomes of the fresh water protozoan Tetrahymena, discovering that the DNA sequence ends of chromosomes consisted of simple repeated DNA sequences. As Gall has recalled,3 they didn't fully appreciate the revolutionary nature of the discovery at that time.
The work Liz was doing in my lab was technically advanced, because she was using techniques learend in Sanger's lab, and virtually no one else in the world was doing that kind of work. We were interested in sequencing partly because it was something you could do and we knew there were unusual features about these molecules. At the time, we didn't say, Eureka, we found what the ends of chromosomes are like. She had made a discovery whose significance we didn't yet appreciate completely. I knew Liz was extremely good, but I didn't know she as a superstar until she started doing her own independent work.
After completing her postdoc, Blackburn joined the faculty of the University of California at Berkeley in 1978, where she continued her study of telomere biochemistry. There she and one of her graduate students, Carol Greider, discovered telomerase, the enzyme that adds telomere DNA sequences to the ends of chromosomes (read more about that below). In 1990 Blackburn moved her lab to the University of California at San Francisco, where she continues to study telomere function and biochemistry.

Blackburn has also been involved in the political side of science. In 2001 she was appointed by the Bush administration as a scientist member of the President's Council on Bioethics. Blackburn and fellow panelist Janet Rowley were very critical of the scientific content of the Council's reports on stem cell research and aging. Her removal from the panel in 2004 drew criticism from scientists who believed she was removed because of her advocacy for human embryonic stem cell research and therapeutic cloning.

A few key publications:
Additional information about Elizabeth Blackburn:
Carol W. Greider

Carol Greider grew up in Davis, California, the daughter of two scientists: her mother was a biologist, who died when Greider was six and her father was a physicist at UC Davis.

Greider got her first taste of hands-on research when she was a freshman at the University of California at Santa Barbara under the mentorship of Bea Sweeney, and ended up working in several labs before deciding that she wanted to pursue biochemistry. She applied to a number of graduate programs, but ran into a problem:
“I had great research experience, great letters of recommendation, and outstanding grades, but I had poor GREs.” Although she did not know it growing up, Greider suffers from dyslexia, which affected her scores on standardized tests. Only two schools—the California Institute of Technology (Pasadena, CA) and the University of California, Berkeley— offered her an interview. When she met with cell biologist Elizabeth Blackburn in Berkeley, things clicked again. “I really liked my conversations with Liz, and there were a number of other people in the department that would be potentially fun to work with, so I went there,” says Greider.
It was while working in Blackburn's lab in 1984 that Greider discovered telomerase, an enzyme that maintains telomere sequences. The account of her discovery in the biography published upon her election to the National Academy of Sciences explains the skill and hard work that went into that achievement:
"If you were easily intimidated, you wouldn't take on that kind of project," Blackburn says. "We had to be both rigorous and enterprising, and those are exactly the characteristics that Carol has. the combination is a great strength." For her part, Greider worked 12-hour days and supplemented her existing biochemistry knowledge with DNA cloning techniques and other skills needed for the project.

Nine months after she began the project, and after much trial and error finding the right substrate and assay, Greider identified the first signs of her enzyme. On Christmas Day in 1984, she developed one of her gels and saw a ladder of the characteristic Tetrahymena 6-base telomeric repeats - exactly the pattern that would be expected from a telomere-synthesizing enzyme.
Of course that was just the beginning. Greider and Blackburn had to rule out the possibility that the results were an artifact. It wasn't until June of 1985 that they were completely convinced that they had isolated the correct enzyme. Greider and Blackburn seem to have had a very good working relationship, which likely contributed to her success.

After receiving her PhD, Greider continued research on the biochemistry of telomerase and the biological function of telomeres at Cold Spring Harbor, first as an independent fellow and then as an Investigator. She moved her lab to the Department of Molecular Biology and Genetics at Johns Hopkins University School of Medicine in 1997 where she is continues her research today.

A few key publications:
Additional information about Carol Greider:
Of course Jack Szostak also made important contributions to the understanding of telomere function (among other achievements), and you can read about his work in some of the other posts in the blogsphere about the award:
1. Aglets, as any regular crossword puzzle worker knows.
2. Joseph Gall was (and is) well known for providing a supportive environment for women scientists in his lab. Many successful women scientists have been members of his lab, including Blackburn, Mary-Lou Pardue, Susan Gerbi, Joan Steitz and Virginia Zakian.
3. Quoted in Elizabeth Blackburn and the story of telomeres; deciphering the ends of DNA by Catherine Brady.

Photos: Left is Eliabeth Blackburn, right is Carol W. Greider. Both taken by Wikipedia Author Gerbil in March 2009. Licensed by Attribution Share Alike 3.0
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Thursday, October 01, 2009

I Am a Technical Woman

OK, I'm not really that technical - but the women in this nifty video that's currently making the rounds definitely are:

The video was shot at the 2008 Grace Hopper Celebration and compiled by the Anita Borg Institute for Women and Technology.

The Anita Borg Institute has also posted biographical videos of their 2009 award winners and conference speakers:

Related links:

(Video via the Geek Feminism Blog)
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