Friday, February 8, 2008

SARS and Quorum Sensing

There is a chapter in The Cockroach Catcher called “SARS, Freedom and Knowledge”. I wrote about the SARS virus:

“For the first time, doctors and nurses who were normally in the forefront of the fight against diseases were fighting for survival from SARS (Severe Acute Respiratory Syndrome), a new and dangerously contagious disease. ……
Our knowledge base was in total chaos. What we knew was obviously not good enough. Nor were the most up to date antiviral drugs……”

I am not a bacteriologist nor virologist but that did not stop me writing about these little creatures.

When I picked up the in-flight magazine on a recent flight, an article titled “Genius at Work” caught my eye. Bonnie Bassler is the bacteriologist at Princeton who discovered and pioneered the work on what she now called quorum sensing in microbes. To be more precise her initial work was with Vibrio harveyi. Vibrio is in the family of bacteria that causes Cholera. Vibrio vulnificus is carried by oysters and was most likely responsible for the serious illness of Michael Winner, film producer and now food writer of the London Sunday Times.

On following this up back home, I found an article on the website of Howard Hughes Medical Institute – she is one of the HHMI Investigators. From this article, I learned that:

“Virulent bacteria do not want to begin secreting toxins too soon, or the host's immune system will quickly eliminate the nascent infection. Instead, Bassler explained, using quorum sensing, the bacteria count themselves and when they reach a sufficiently high number, they all launch their attack simultaneously. This way, the bacteria are more likely to overpower the immune system….

For the past three hundred years……we’ve been completely wrong……we don’t know anything about bacteria until about a decade ago….”

Wow! Just as we thought we knew everything there is to know about microbes.
Bonnie Bassler will one day get the Nobel prize for medicine. You read it here first.

Fascinated, I wanted to find out more about this genius. I would like to share with you her answers to some of questions that children were invited to ask about her life and work:

“You all asked me essentially the same question: how and when did I get interested in science. As a kid, I loved doing puzzles, solving riddles, and reading mystery books. I also loved animals and always had pets. Around high school, those interests (puzzle solving and animals) convinced me that I should be a veterinarian so I could work on mysterious illnesses in animals and cure them. In college, I realized I did not like big-bloody stuff. It became clear to me that I probably wouldn't enjoy being a vet, but I did not know what I'd do instead.

Fortunately, the vet curriculum required me to take biochemistry, genetics, and lab courses. Once I got into those classes, I fell in love with doing puzzles about little things (DNA and RNA and proteins and how they all fit together in cells). I also adored doing lab experiments and puzzling over my results. I realized that lab research was the perfect path for me. It allowed me to spend every day figuring out mysteries/puzzles that have to do with what make us alive. What could be a bigger mystery or puzzle? I changed my major in my junior year, and I have not left the lab since. (I still love animals and have a pet—Spark my cat—and I often go hiking hoping to see animals in the wild.)
I think being open-minded about what Nature is trying to tell you is the key to being creative and successful.”


Now in England, only a couple of Medical Schools require biology. In my book, I puzzled over this fact:

“The ability to dissect out a full set of cockroach salivary glands was a prerequisite requirement for medical school entrance in Hong Kong in our days. It is almost a 180 degree turn around nowadays when many young doctors have no idea about the biological world we live in. Nearly all Medical Schools in England no longer specify biology as a prerequisite subject for anybody who wishes to embark on the study of the human body. As we are so intertwined with the rest of the living biological world I find this policy quite extraordinary.”

7 comments:

Medically Brunette said...

Actually no, we've just finished the combined microbiology, infection, immunology & pathology module and this was never mentioned! not once! Interesting link though, nothing like the internet to disseminate knowledge!

Am Ang Zhang said...

You are right – nothing like the internet, and the blog is one of the best things that have happened. I continue to be fascinated by anything related to the natural world in which we live. There is fun in Medicine – guidelines or no guidelines. We need a few young minds to continue the quest to look for new things.

Sarah said...

I have a very intelligent and enquiring god-daughter, who is determined to carry on the quest and become a doctor, at the moment a brain surgeon, regardless of guidelines. At the moment she is 15, so a few years to wait yet. She's a medical blonde, but does play rugby at county level, so I think will stick to her guns........Sarah

Am Ang Zhang said...

Bassler's links are quite amazing and she talked to young kids and is very inspiring. Great to hear of her ambitions.I would switch to table tennis or golf though.

laystranger said...

Quorum sensing also happens with locusts:

http://www.newscientist.com/article/dn9255-how-locusts-decide-its-time-to-swarm.html

http://www.pnas.org/content/98/7/3895.abstract?ck=nck

Presumably something similar goes on with human groups such as football hooligans.

laystranger said...
This comment has been removed by the author.
Anonymous said...

Interesting how Influenza/Swine flu allow simple bacteria like Streptococcus to act.