BMAA and ALS: A Close Look at Eutrophication

The overall equation representing one of life’s ultimate achievements, photosynthesis, is the biggest oversimplification you will find in any basic science book on the planet. It shows water, carbon dioxide and sunlight as reactants and glucose and oxygen as products. It does not hint at the intricate cascade of events that have to transfer electrons from water to carriers to chlorophyll; on to more carriers and other chlorophyll molecules and still more shuttle bus-like molecules and eventually to carbon dioxide and other reactants of the Calvin cycle.

It overlooks the accessory pigments that help chlorophyll capture more energy from the sun. It ignores the components of the membranes that separate hydrogen ion concentrations supplying the voltage needed to make the reaction facilitator, ATP, and all the enzymes that accelerate the entire food-making process of plants.

Reaction rates in chemistry are controlled by their slow intermediary steps. Photosynthesis and subsequent plant growth rates are controlled by the amount of light, which initiates the process; by temperature, which controls the carbon-dioxide fixing rate; by water-availability and by certain limiting ions. In other words, there is usually ample carbon dioxide available, but other minor, yet crucial substances are often scarce and control the growth of both land and aquatic plants. For algae, such limiting ions, mainly phosphate(PO43- and nitrate(NO3) are needed to make those behind the scene-molecules just mentioned: nitrogen-containing enzymes and ATP, which have N-compounds and phosphate, and they are also needed to synthesize genetic material.

But what happens when limiting ions suddenly become available in greater quantities to bodies of water? They cause eutrophication, which is a state of excess plant and algal growth. Although the process can occur naturally, humans are masters at accentuating it. Runoff fertilizer from nearby agricultural activities, sewage and industrial effluents all contain nitrates and phosphates, which directly lead to population explosions of algae, so called algal blooms.

As algal growth goes out of control, light has a harder time penetrating the water and its pH rises, both of which impact certain predators and shore plants. When excess algae die as part of their life cycles, their decomposition consumes dissolved oxygen, killing fish. Such hypoxic events are affecting over 245 000 square kilometers worldwide.

The foul smell of algal blooms is also a sign of more chemistry gone awry. Depending on the algal species that proliferate, eutrophication at times produces toxins that threaten drinking water supplies, recreational swimming and consumption of seafood. More specifically species of a group of photosynthetic bacteria, cyanobacteria,  produce compounds such as an enzyme-binding microcystin and the neurotoxin anatoxin-a, which mimics the neurotransmitter acetylcholine.

One of several microcytins, the LR refers to variant amino acids

One of several microcytins, microcystin-LR— the LR refers to the variant amino acids leucine and arginine.

In Canada, the Federal-Provincial-Territorial Subcommittee on Drinking Water recommends a maximum acceptable concentration of 0.0015 mg/L for total microcystins in drinking water, based on the toxicity of microcystin-LR. That is equivalent to 1.5 parts per billion, attesting to their high toxicity and to the fact that these compounds resist boiling.

Another cyanobacterial neurotoxin , β-methylamino-ʟ-alanine (BMAA), found in contaminated seafood and shellfish, drinking water supplies, and recreational waters—may be a factor in Lou Gehrig’s disease (amyotrophic lateral sclerosis, or ALS) and possibly other neurodegenerative conditions.

BMAA

BMAA

The toxin is produced by 95% of the cyanobacteria genera tested, and although it is not one of the 20 amino acids building blocks used by organisms, it does get mistakenly incorporated into proteins.

Accumulation of BMAA in the proteins of nerve cells, which need to last a lifetime, would provide a mechanism for how the toxin might biomagnify. “The problem with neurons is they do not divide, as a general rule, so over time they accumulate damaged proteins, and once they reach a critical level, it causes the cell to undergo apoptosis [cell death],” explains Rachael Dunlop, a researcher with the Heart Research Institute in Sydney, Australia.

Dunlop and others also found that at least in test tubes, a transfer RNA enzyme mistakenly picks up BMAA and incorporates it into proteins. More recently Dunlop and another researcher have mentioned that genes in certain individuals make them more sensitive to BMAA, which unfortunately is not presently screened for in municipal water analyses.

Advertisement

An Hour for Every Star

Since the estimate for the number of stars in the universe is somewhere in the ballpark of 1022 to 1024, a chemist could be forgiven if he imagined that there are a mole of stars out there: 6.022 X 1023 . That would imply that for every molecule of water filling a slightly over-sized tablespoon, there is approximately one star in the universe, like one of the various sun-types on the main sequence or like one of the dwarfs or soon-to explode-giants.
Betelgeuse_Sky90_Greg_Noel_Online
There are in fact so many stars that if you programmed a computerized telescope for every person on earth to devote just an hour to explore each different star, it would take the lifespan of our sun, 10 billion years, to complete the task.

It’s a humble reminder that even if we had the mental capacity, we would be incapable of knowing everything because of the time restriction. From the point of view of an individual life, which is far more restricted in both aptitude and duration, that truth becomes even more pronounced. But that should not deprive anyone or any civilization from continuing the enjoyable journey of mental discovery.

Of course, it would be naive to think that science is restricted to gaining a better understanding of the world around us. It is tainted when it serves politics, our egos and unsustainable economies. But as pure as it could be in an ideal world, it would never make literature, humanities and the arts less important because those realms address morals, aesthetics and everyday individual existence in a way that science could barely touch. Conversely, too often people in those disciplines do not realize how important creativity has always been in designing experiments and in creating scientific models that make often highly abstract ideas more tangible.

With regard to cosmology, science is far from having all the answers. But different religions have contradictory explanations about the origin of the universe, so it’s more likely that they are all incorrect rather than assume that a single religion stumbled upon the truth, especially when none of the ideas are based on any evidence. But even in a scientific world, those who use religion to live in a more humble and selfless manner rightfully should continue to abide by their beliefs. But I don’t see how dropping the creation myths would get in the way of better behavior.

And for those who claim allegiance to religion while being as selfish as anyone else, they would be better off dropping the whole thing. In the same manner, science does not need those who fudge, twist their data or sell it to a lesser cause.

What Has Happened to Scientific American Over the Years?

I started reading Scientific American in college.  Our biology textbook referenced articles from this magazine, which for decades has had well-illustrated articles about current research in a variety of scientific disciplines. It was never a scholarly journal, but its articles were far less fluffy than those of a newspaper or a typical magazine. Yet gradually, over a period of two to three decades, despite its glossy pages, added color, web links and other bells and whistles, the magazine has become a shadow of its former self. It is a story that is not too different from what has happened to the content of most high school science courses and textbooks.

scamdec82_2014

The contrasting styles of the December 1982 and 2014 covers. They once used just one advertising director. Now the magazine makes use of a small army of marketing and sales people.

Here’s the evidence. We’ll start with its cover. Anything of quality that has a history dating back to the 1800s does not have to promote itself. The December 1982 cover’s simplicity attests to that, while 32 years later, the cover uses hyperbole, bits of content and graphics in an attempt to lure the reader to look inside.

For a price of $2.50 in 1982 ($6.13 in today’s dollars) there were 178 pages, as opposed to the 100 that are now published for a cover price of $6.99.  Over the years, Nobel Prize winners contributed 245 articles to Scientific American. In 1982, seven of the 8 articles were written by researchers, the other by a scholar. The December 2014 issue only offered 6 main articles, two of which were written by freelance writers. There was once an entire page dedicated to biographies of the issue’s authors. Now each contributor’s background is reduced to a tiny blurb. Most importantly, three decades ago, the main articles were more thorough with more graphics, diagrams and captions, revealing more experimental detail.

To illustrate this point, let’s examine the December 1982 issue’s best article, Samples of the Milky Way. The editors and authors clearly saw themselves as educators.  Before getting to the actual discovery, the article took its time to explain the background knowledge needed to understand it: the basics of isotopes; the workings of the mass spectrometer instrument that separates them and identifies their abundance;  how isotopes are monitored in space and how their ratios depend on the evolution of stars. A few hypotheses were proposed for a cosmic anomaly , a high proportion of the 22Ne isotope relative to what is found in the solar system.  Interestingly the idea that was considered to be the most radical proposal at the time was actually the one that’s currently accepted today. The oddities in that isotopic ratio and others were the result of our solar system being atypical, due to injection of nearby supernova material. What had led to that idea is that meteors had recently revealed unusual ratios of  27Al  and 26Mg, a signature of the short-lived 26Al. Due to its instability, the latter could not have been incorporated into meteorites unless it had been recently introduced by what has been cleverly dubbed as “supernova confetti“.

Twenty eight editors and seven people from the art department are now needed to put out an issue with as much concern for education as for marketing. About half the number of editors and artists were involved in 1982. Similarly, in nearly half a century, no small army of the North American textbook industry’s dubiously-selected authors, graphic artists, photographers, and marketing specialists has been able to come anywhere close to the quality of a high school chemistry textbook such as Cotton and Lynch’s 1968 Chemistry: an Investigative Approach. In just one example, instead of just throwing the Thomson model at the students with a very colorful diagram of the experimental setup, the authors took the time to explain how analysis of the curvature of the cathode rays in a magnetic field led to a calculation of charge to mass ratio of the electron. Later with Millikan’s oil drop experiment and the charge to electron ratio, a simple ratio of the latter to that of Thomson’s result revealed the mass of the electron.

The one-time excellent book review section of Scientific American, written by long-time contributors Philip Morrison and his wife, makes sporadic and less dedicated appearances.  An  insightful Amateur Scientist section written by physics professor and author Jearl Walker has been replaced by editor Steven Mirsky’s  more-silly-than-humorous anti-gravity column. The 50 and 100 Years Ago section has been understandably replaced by 50, 100 and 150 Years Ago , which ironically has become shorter in length, as if the editors assume that readers are not interested in the past and in how science changes over the years. Perhaps if the editors included too much from past issues, more new readers might realize how they are getting less quantity and less quality for a greater cost, especially in light of predatory pricing aimed at libraries.