How a deadly substance may someday cure you of cancer
The first 30 minutes of Dr. Ron Oremland’s SNARL (Sierra Nevada Aquatic Research Lab) lecture on Tuesday transported listeners back to a high school or college chemistry class. For those of us who weren’t any good at chemistry, eyes began to glaze over and the mind began to wander as the “professor” discussed the periodic table, electrons, and redox reactions, just as he had in our teenage years.
Thankfully, Dr. Oremland, a Senior Research Scientist for the U.S. Geologic Survey (USGS), seemed to understand that his audience wasn’t full of biochemists. He worked some comedic relief into his talk, at times gesturing wildly, speaking with a Brooklyn accent and making bawdy references to the deadly effects of arsenic (the main topic of his lecture) in order to hold the interest of everyone in the room while conveying the facts.
Dr. Oremland’s talk on “Arsenic and the Meaning of Life” kicked off the annual lecture series presented by the Sierra Nevada Aquatic Research Lab (SNARL). Each spring, SNARL hosts about a half dozen lectures for the public at the Green Church at the intersection of Benton Crossing Rd. and Highway 395 at the south end of the airport runway. Each lecture is free and lasts about an hour. Lectures are always presented by the top brass in scientific fields. Dr. Oremland, for example, worked side by side with Dr. Felise Wolfe-Simon, guiding her during the discovery of the bacteria in Mono Lake that is able to use arsenic instead of phosphorous to survive. The discovery received a lot of attention when Wolfe-Simon held a press conference with NASA to explain the findings on Dec. 2, 2010.
During the second half of his lecture, when Dr. Oremland moved away from the scientific elements and electrons, he explained that the bacterium found in Mono Lake was not a new organism. Halomonas, or the bacteria that can make do with arsenic rather than phosphorous, has been found before. GFAJ, as the microbe in Mono Lake was named, is a strain of Halomonas.
“The way the information was disseminated upset a lot of people, but we stand by our results,” Dr. Oremland said, referring to the media storm that followed Wolfe-Simon’s press conference, which led to the release of a lot of misinformation and a lot of criticism from other scientists.
Dr. Oremland explained the experiment in very simple terms. “I told Wolfe-Simon to test the bacteria by either removing phosphorous and replacing it with arsenic or removing oxygen and replacing it with selenium,” he said. “Replace it and see what crawls out.”
For those chemistry buffs, phosphorous would be replaced by arsenic and oxygen by selenium because of the way these elements line up on the periodic table. The scientists chose to try the phosphorous replacement with arsenic.
“What we found was that the bacteria with the arsenic doesn’t grow as well as with phosphorous, but it still does pretty well,” Oremland explained. “The bacterium doesn’t grow at all when neither [elements] are present.” He also clarified that when arsenic is substituted for phosphorous in DNA, the genetic code stays the same but the framework changes.
Dr. Oremland then hypothesized on larger implications of arsenic.
“I’m always telling my wife, Fran, not to eat so much lobster because there’s a lot of arsenic in lobster,” Dr. Oremland explained in his jovial tone. “Luckily we pee most of it out.” However, the arsenic in creatures such as lobster made Dr. Oremland question why these animals would be carrying around such a toxic substance in their bodies.
“Maybe animals in the ocean [where phosphorous can be low] use arsenic when they are low on phosphorous,” Dr. Oremland said. “Perhaps they carry it in reserve for a rainy day to make due until things get better [and they can find more phosphorous].”
On an even grander scale, Dr. Oremland pointed to arsenic’s anti-cancer properties. Certain arsenic compounds are used as chemotherapy treatments, but Dr. Oremland wondered aloud whether or not replacing phosphorous with arsenic in cancer cells would confuse the cancer cells enough to slow them down. Since the rapid growth of these cells is often a big factor for cancer patients, slowing down that growth could be a key component to a patient’s survival.
Dr. Oremland left the audience with this thought as well as the realization that an element that can be quite deadly in most forms could potentially be harnessed to rid our bodies of something else just as toxic.
SNARL lectures take place every Tuesday at 7 p.m. (except for the final lecture this year, which will be held on Friday, June 3 to accommodate the speaker’s schedule).
Next week’s speaker is Dr. Susan Hough from the USGS. Her lecture is titled “The 1872 Lone Pine Earthquake and Recent Activity in Long Valley.” Hough has recently been the lead spokesperson from USGS for the LA Times on the recent earthquakes in Christchurch, New Zealand and in Japan.