Wednesday, October 30, 2013

Follow-Up on Hershey and Chase

I wanted to post a link to a cool scientific paper that I saw when I was doing research for the previous post on Martha Chase.  It is called "A Single-Molecule Hershey-Chase Experiment" by Van Valen, et al., and was published in the journal Current Biology.  It is available to read here for free. 

These researchers took phages with DNA that was labeled with a fluorescent cyanine dye.  Using a fluorescence microscope, they monitored the time it takes for the bacteriophages to inject the DNA into E. coli bacteria cells (approximately 5-10 seconds).  Figure 1 of the paper shows their experimental scheme while Figure 2 shows an actual experiment.  It is definitely worth checking out if you are interested in bacteriophages or the Hershey-Chase experiment.    

Monday, October 28, 2013

Gender Bias in Science, Part IV: Martha Chase

Martha Chase in 1953
Many readers who have taken a high school- or college-level biology class in the past 50 years have likely heard of the "Hershey-Chase" experiment, performed in 1952.  Sometimes its called "Hershey & Chase" or even sometimes just "the blender experiment."  You might not remember it, but you probably learned about it at one time or another if you took some kind of biology course.  It's that important and that famous.   

The subject of today's post is the Dr. Martha Chase of "Hershey-Chase" fame.  Her name will be forever associated with what is considered to be the definitive experiment showing that DNA, not protein, is the inheritable genetic material.  Let's rephrase that, because it is an important discovery that we take for granted today: Hershey and Chase showed that genes are made of DNA, not protein.  As you can imagine, that was a big deal.  Before that, many scientists thought that DNA was frankly not very important and pretty uninteresting.  Many thought that genes were instead made out of protein.  Hershey and Chase forever changed that with a simple series of experiments.    

We'll get into the historical background of the experiments in a moment.  If you've read some of the previous posts in this series, you can probably guess that the reason we're talking about Chase is that, despite this impressive experiment that bears her name, Martha Chase watched Alfred Hershey receive a Nobel Prize in 1969 for the discovery, while she sat on the sidelines.

Was this an example of gender bias, or simply a case of giving credit to the more deserving half of the pair?  Let's talk about the facts of the case.  We'll go through the Hershey-Chase experiment and the somewhat tragic life of a legendary geneticist after the jump.        

Sunday, October 13, 2013

Rising Levels of Marijuana Poisonings in Pets

"Did someone say 'cookies?'"
Following up on a previous post on this blog about foods that can be poisonous to pets, I saw an article today from Huffington Post that notes that marijuana poisonings in pets are on the rise, partly due to the increased use of medical marijuana.  Medical marijuana that is put into baked goods or other snacks is an easy way for dogs or cats to quickly ingest a high and potentially toxic dose of the drug.  Dogs don't know the difference between cookies and "special" cookies; it is all the same delicious temptation to them.  Studies have already shown a correlation between increases in the numbers of medical marijuana licenses in certain states and the numbers of marijuana poisonings seen at local vet clinics. 

Let's talk a bit about what marijuana does in the body as well a why medical marijuana is a particular danger to pets.  The goal of this post is not to advocate or criticize medical marijuana (we're not getting into politics), but to just discuss some of the facts and science behind it.     


Monday, October 7, 2013

Gender Bias in Science, Part III: Chien-Shiung Wu

Marie Curie in 1911
Marge:   Sweetie, you could go to McGill, the Harvard of Canada
Lisa:   Anything that's the "something" of the "something" isn't really the "anything" of "anything."
--The Simpsons, "MoneyBart," 2010

The opening quote isn't meant to make fun of McGill (it's a very fine school), but rather to illustrate the point that calling something the "something of the something" can be seen as either a complement or an insult, depending on how you look at it.  For example, people often refer to McGill as the "Harvard of Canada" or refer to Duke as the "Harvard of the South."  Oftentimes the use of those phrases has complementary intentions, but when viewed from another angle, comparing the quality of these two institutions to Harvard (as a sort of "gold standard" for institutions) diminishes their individuality, individual strengths, and identities.  

Curie and Henri Poincare in 1911
This also happens a lot with famous women in science in history.  Lise Meitner was referred to by Einstein as the "German Madame Curie."  The woman scientist of today's post, Chien-Shiung Wu, was often referred to as the "Chinese Madame Curie" or simply as "Madame Wu."  These titles have been bestowed upon these women with good intentions; Madame Curie was obviously brilliant, and being compared with her is a complement for anyone, but it diminishes the individual discoveries and legacy of Meitner and Wu to refer to them in relation to Curie (as some sort of "gold standard" of a woman in science).  They were not "ethnic" copies of Madame Curie.  They were individuals who made brilliant scientific contributions in their own rights, yet unlike Curie, they didn't get the Nobel Prize they each deserved.

This is Part III of an ongoing series detailing some of the past and present issues faced by women in science, with a discussion of famous woman scientists who were denied science's highest prize, the Nobel Prize.  Part I focused on the nuclear physicist Lise Meitner, while Part II discussed the astrophysicist Jocelyn Bell Burnell.

Let's now talk another physicist, Chien-Shiung Wu, who has also been referred to as the "First Lady of Physics."