New compounds discovered that are hundreds of times more mutagenic

Jan 06, 2014
Research suggests that combustion from various sources, or such processes as the grilling of meat, may create new mutagens that were not previously known. Credit: Heather Luis, courtesy U.S. Department of Agriculture

(Phys.org) —Researchers at Oregon State University have discovered novel compounds produced by certain types of chemical reactions – such as those found in vehicle exhaust or grilling meat - that are hundreds of times more mutagenic than their parent compounds which are known carcinogens.

These compounds were not previously known to exist, and raise additional concerns about the health impacts of heavily-polluted urban air or dietary exposure. It's not yet been determined in what level the compounds might be present, and no health standards now exist for them.

The findings were published in December in Environmental Science and Technology, a professional journal.

The compounds were identified in laboratory experiments that mimic the type of conditions which might be found from the combustion and exhaust in cars and trucks, or the grilling of meat over a flame.

"Some of the compounds that we've discovered are far more mutagenic than we previously understood, and may exist in the environment as a result of heavy air pollution from vehicles or some types of food preparation," said Staci Simonich, a professor of chemistry and toxicology in the OSU College of Agricultural Sciences.

"We don't know at this point what levels may be present, and will explore that in continued research," she said.

The parent compounds involved in this research are polycyclic aromatic hydrocarbons, or PAHs, formed naturally as the result of almost any type of combustion, from a wood stove to an automobile engine, cigarette or a coal-fired power plant. Many PAHs, such as benzopyrene, are known to be carcinogenic, believed to be more of a health concern that has been appreciated in the past, and are the subject of extensive research at OSU and elsewhere around the world.

The PAHs can become even more of a problem when they chemically interact with nitrogen to become "nitrated," or NPAHs, scientists say. The newly-discovered are NPAHs that were unknown to this point.

This study found that the direct mutagenicity of the NPAHs with one nitrogen group can increase 6 to 432 times more than the parent compound. NPAHs based on two nitrogen groups can be 272 to 467 times more mutagenic. Mutagens are chemicals that can cause DNA damage in cells that in turn can cause cancer.

For technical reasons based on how the mutagenic assays are conducted, the researchers said these numbers may actually understate the increase in toxicity – it could be even higher.

These discoveries are an outgrowth of research on PAHs that was done by Simonich at the Beijing Summer Olympic Games in 2008, when extensive studies of urban air quality were conducted, in part, based on concerns about impacts on athletes and visitors to the games.

Beijing, like some other cities in Asia, has significant problems with air quality, and may be 10-50 times more polluted than some major urban areas in the U.S. with air concerns, such as the Los Angeles basin.

An agency of the World Health Organization announced last fall that it now considers outdoor air pollution, especially , to be carcinogenic, and cause other health problems as well. PAHs are one of the types of pollutants found on particulate matter in air pollution that are of special concern.

Concerns about the heavy levels of air pollution from some Asian cities are sufficient that Simonich is doing monitoring on Oregon's Mount Bachelor, a 9,065-foot mountain in the central Oregon Cascade Range. Researchers want to determine what levels of may be found there after traveling thousands of miles across the Pacific Ocean.

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210
3.7 / 5 (3) Jan 06, 2014
Was in Beijing and Shanghai a few months back.....OMG!!!! You never see the sun or sky due to MEGA-air pollution. The TRAFFIC....the traffic jams that last literally for days and if there was a vehicle accident, the traffic 'surrounds' the vehicles so completely, yes surrounds, they have to airlift the dead and injured out! As soon as new roads are constructed to relieve congestion, they are JAMMED eternally! i think China and Russia should trade places! China would even fill Siberia in a day!

word-to-ya-muthas
tadchem
2.3 / 5 (3) Jan 06, 2014
Naturally-occurring radioactive carbon-14 (approximately one of every billion carbon atoms in all the food we eat - save salt or water) has a 100% chance of causing a mutation in DNA if it decays after being incorporated into the DNA - which is approximately 40% by weight carbon). Statistically several hundred carbon-14 atoms are in the DNA of EACH cell in a human body.
With billions of cells in the body, and a half-life of only a few thousand years (180 billion seconds), there is approximately one DNA mutation occurring each second in a human body - just due to the natural radiation of the food we have already eaten.
210
3.7 / 5 (3) Jan 06, 2014
Naturally-occurring radioactive carbon-14 (approximately one of every billion carbon atoms in all the food we eat - save salt or water) has a 100% chance of causing a mutation in DNA if it decays after being incorporated into the DNA - which is approximately 40% by weight carbon). Statistically several hundred carbon-14 atoms are in the DNA of EACH cell in a human body.
With billions of cells in the body, and a half-life of only a few thousand years (180 billion seconds), there is approximately one DNA mutation occurring each second in a human body - just due to the natural radiation of the food we have already eaten.

OK. Our science at present indicates several mechanisms for DNA repair. Further, at the rate of mutation you state, and the projected human evolutionary lifetime of between 3 and 3.5 Million years, evolutionary pressures would be defeated by c14 decay in all cases. Damaged DNA, yes, MUTATED DNA...that is too much or we once had a lot more DNA or correction.
Telekinetic
3.5 / 5 (2) Jan 06, 2014
What isn't being addressed is why mankind exposes and jeopardizes innocent bystanders to his toxic endeavors. When smoking is banned from restaurants, the sidewalks outside become a noxious gauntlet of cigarette smoke. On the bottom, the world is suicidal, but like a shooter in a school, they'll take everyone with them first.
Returners
3 / 5 (4) Jan 06, 2014
What isn't being addressed is why mankind exposes and jeopardizes innocent bystanders to his toxic endeavors. When smoking is banned from restaurants, the sidewalks outside become a noxious gauntlet of cigarette smoke. On the bottom, the world is suicidal, but like a shooter in a school, they'll take everyone with them first.


You didn't actually expect addicts to do the right thing without being forced to, did you?

When they ban them from sidewalks, they'll just stand in the grass or the street, or hide behind the building.
tadchem
5 / 5 (1) Jan 07, 2014
OK. Our science at present indicates several mechanisms for DNA repair. Further, at the rate of mutation you state, and the projected human evolutionary lifetime of between 3 and 3.5 Million years, evolutionary pressures would be defeated by c14 decay in all cases.


My point is that C-14 set the upper bound for mutagenic strength with 100% effectiveness for each decay. It would seem you are discounting the effectiveness of the DNA repair mechanisms you yourself have brought into the discussion. Evolutionary pressures are not 'defeated'. Mutation introduces the necessary genetic changes that provide the mechanism for evolutionary adaptation.
210
3 / 5 (3) Jan 07, 2014
OK. Our science at present indicates several mechanisms for DNA repair. Further, at the rate of mutation you state, and the projected human evolutionary lifetime of between 3 and 3.5 Million years, evolutionary pressures would be defeated by c14 decay in all cases.


My point is that C-14 set the upper bound for mutagenic strength with 100% effectiveness for each decay. It would seem you are discounting the effectiveness of the DNA repair mechanisms you yourself have brought into the discussion. Evolutionary pressures are not 'defeated'. Mutation introduces the necessary genetic changes that provide the mechanism for evolutionary adaptation.

At the RATES you state, evolution is NOT supported by a mutation rate of that speed! DNA damage is likely but NOT mutation at that rate. At THAT rate each and every birth would produce a new species, no. At the rates you state each mutation would then be damaged/mutated. Mutation is NOT the only affector of evolution.
word-
210
3 / 5 (2) Jan 07, 2014
My point is that C-14 set the upper bound for mutagenic strength with 100% effectiveness for each decay. It would seem you are discounting the effectiveness of the DNA repair mechanisms you yourself have brought into the discussion. Evolutionary pressures are not 'defeated'. Mutation introduces the necessary genetic changes that provide the mechanism for evolutionary adaptation.

Living beings on this planet live their ENTIRE lives undergoing the ravages of DNA damage. IF c14 was a constant MUTATOR as you say, we would see evolution changing the full spectrum of life in real-time right before our eyes. New species would evolve in every life form RIGHT NOW/each second, if things worked the way you say. Much of human evolution involves 'pressure' on our genes from a RANGE of environmental factors (UV radiation, etc) as well as infection and even social elements. That c14 causes damage is accepted, granted, EXPECTED. But mutation cannot and is not happening as fast as you say.
Returners
3 / 5 (2) Jan 07, 2014
... New species would evolve in every life form RIGHT NOW/each second, if things worked the way you say.


Nah. Damaged reproductive cells, i.e. gametes, etc, anything with relatively negative traits affecting their own propulsion or growth would immediately be selected out. Damaged cells causing functional or chemical incompatibilities between the male and female gamete are selected out. Functional or chemical incompatibilities between Zygote and uterine lining are selected out. Mutations resulting in most notable physical changes, like head or heart size or organs, would most likely be miscarried, or die during birth or shortly after.

If you're looking for something like a 6 chamber heart, or a permanent generational genetic change in hair or eye color, most of that stuff, of whatever species, is just not going to survive child birth. Remember most defects like conjoined twins, die without medical intervention, and they are genetically, biochemically compatible.
Returners
2.3 / 5 (3) Jan 07, 2014
Let's look at the 6 chamber heart problem.

Suppose a mutation would potentially cause that. What might it look like?

Normal mammal hears pump de-oxygenated blood to the lungs, then back to the other set of chambers, from there the re-oxygenated blood goes to the brain and body.

If you add another pair of chambers to the heart randomly, it has a 50% chance of ending up pumping deoxygenated blood back to the brain and body. So even if a mutation occurred to add heart chambers to the body, it has a 50% chance of killing the animal, instead of either helping or staying about the same in feasibility or survivability as a normal mammal, even if there are no other physical or chemical negative side-effects.

Nothing in the history of the planet, except maybe box jellyfish, appears to have developed a third or fourth brain hemisphere, and theirs are so simple it probably doesn't matter. For a mammal, bird, or reptile that takes lots of changes: skull size not big enough = death.
Snowflake70
not rated yet Jan 13, 2014
Fast food restaurants are like Burger King and MacDonalds are NOT going to like this ! Lets see what else do we BURN that creates free radicals, coal, oil, garbage, and who's going to tell the volcanoe's we are going to ban burning or any kind of fire ?

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