On dangerous air & the damnation of cyanobacteria.

On dangerous air & the damnation of cyanobacteria.

During the acute phase of the Covid-19 pandemic, I kept thinking of Margarita Engle’s poem “More Dangerous Air.” The title seemed particularly resonant, and its a beautiful poem about growing up in an atmosphere of fear.

Newsmen call it the Cuban Missile Crisis.

Teachers say it’s the end of the world.

Engle documents the way we might flail, attempting to protect ourselves & our loved ones. We know enough to be afraid; we don’t yet know enough to be safe.

Early in the pandemic, people left their groceries on the front steps for days before bringing the bags inside. A year in, we were still needlessly scrubbing surfaces with toxic chemicals.

#

During the missile crisis, school children practiced fire drills, earthquake drills, tornado drills, air raid drills. (They didn’t yet need the contemporary era’s most awful: the active shooter drills.)

Hide under a desk.

Pretend that furniture is enough

to protect us against perilous flames.

Radiation. Contamination. Toxic breath.

The blasts are dangerous. But warfare with atomic weapons is different from other forms of violence. A bomb might kill you, suddenly; the poisoned air might kill you, slowly; the poisoned ground might maim generations yet unborn.

Each air-raid drill is sheer terror,

but some kids giggle.

They don’t believe that death

is real.

Radiation is invisible. Marie Curie didn’t know that it would kill her. Rosalind Franklin didn’t know that it would kill her.

We know, now. At least, some of us do.

Others – including a perilously large cadre of politicians – still think we ought to stockpile a behemoth nuclear arsenal.

Nuclear bomb: photograph by Kelly Michals on flickr.

#

Viruses are invisible. And they act slowly. Breathe in an invisible virus; a week later, you might begin to cough; three weeks later, your cough might worsen; a month after that seemingly innocuous breath in which you sucked a microscopic package of genetic code into your lungs, you might be in the hospital, or worse.

Connecting an eventual death to that first dangerous breath is actually a tricky cognitive feat! The time lag confuses us. It’s much easier for human minds to draw conclusions about closely consecutive events – a vaccine followed within hours or days by fever or heart problems.

#

Greenhouse gases are also invisible. If we drive past a power plant, we might see plumes rising from the towers, but we can’t see poison spilling from our cars, our refrigerators, our air conditioners, our meals. This is just good food on a plate! It doesn’t look like danger.

But we are changing the air, dramatically, in ways that might poison us all. Or – which is perhaps worse – in ways that might not affect us so much, but might make this planet inhospitable to our unborn grandchildren. Perhaps we will be fine. It’s humans born twenty years from now, or fifty years from now, who will suffer more.

#

Each individual can take action. You, as an individual, could fly less, buy less, eat plants.

And yet.

You, as an individual, can only do so much.

When I hide under my frail school desk,

my heart grows as rough and brittle

as the slab of wood

that fails to protect me

from reality’s

gloom.

#

We aren’t the first. Go outside and look around – the vibrant bursts of summer green are delightfully entrancing.

Our minds are plastic things – we make ourselves through the ways we live – but certain scripts were sculpted by our ancestry. Over hundreds of millions of years, the bearers of certain types of brains were more likely to be successful in life.

Creatures like us – who need air to breath, water to drink, shelter from sun and cold – often feel an innate love for the way summer light plays over a heady mix of blue and green.

We need all that green. The plants, the trees, the algae: for humans to survive the climate crisis we’ve been making, we’re depending on them. We need them to eat carbon dioxide from the air, and drink in hydrogen atoms from water, and toss back oxygen for us to breathe.

We’ve been poisoning the air, and they might save us.

Which is ironic, in a way. Because all that green – they wrought our planet’s first global devastation.

Saving us all this time would be like a form of penance.

#

Early in our planet’s history, there was very little oxygen in the air. Which was a good thing for the organisms living then! Oxygen is a very dangerous molecule. When we fall apart with age, it’s largely because “oxidative damage” accumulates in our cells. When grocery stores market a new type of berry as a “superfood,” they often extol its abundance of “antioxidants,” small molecules that might protect us from the ravages of oxygen.

The first living organisms were anaerobic: they did not need, and could not tolerate, oxygen. They obtained energy from sulfur vents or various other chemicals.

But then a particular type of bacteria – cyanobacteria – evolved a way to eat air, pulling energy from sunlight. This was the precursor to modern photosynthesis. Cyanobacteria began to fill the air with (poisonous!) oxygen as waste.

Many years passed safely, though. There was abundant iron then, on land and in the seas – iron drew down oxygen to rust.

Approximately two billion years passed without incident. All that iron buffered our planet’s atmosphere! It must have seemed as though the cyanobacteria could excrete a nearly infinite amount!

But then they reached a tipping point. The iron had all become iron oxides. The concentration of oxygen in the air rose dramatically. This hyper-reactive poison killed almost everything alive.

#

Perhaps cyanobacteria were punished for what they’d done. By filling the world with oxygen, they enabled the evolution of organisms with higher metabolisms. Creatures who lived faster, shorter lives, turbocharged by all that dangerous air. And these creatures – our forebears – nearly grazed their enablers out of existence.

Cyanobacteria were once masters of the universe. Then they were food.

And they were imprisoned within the cells of plants. Look up at a tree – each green leaf is a holding cell, brimming with cyanobacteria who are no longer free to live on their own. Grasses, ferns, flowers – every photosynthetic cell home to perhaps dozens of chloroplasts, the descendants of those who caused our planet’s first mass extinction.

A few outlaws linger in the ocean. Some cyanobactera still pumping oxygen into the air, the lethal poison that’s gulped so greedily by human lungs. Their lethal poison now enables our growth, our flourishing, our reckless abasement of the world.

And we are poisoning the air in turn, albeit in a very different way. In our quest to use many years’ stored sunlight each year, we dig up & burn the subterranean remnants of long-dead plants. The prison cells in which cyanobacteria once lived and died, entombed for millions of years within the earth, now the fuel for our own self-imposed damnation. The concentration of carbon dioxide in the air is slowly rising. Our atmosphere is buffered; for a while, our world will seem unchanged. Until, suddenly, it doesn’t.

Some species, surely, will survive. Will thrive in the hotter, swingier, stormier world we’re making.

It likely won’t be us.

On the study of naked mole-rats.

On the study of naked mole-rats.

This is a riff on an essay from several years ago.

In 1974, evolutionary biologist Richard Alexander gave a lecture describing the conditions that might spawn eusocial vertebrates. 

Alexander was a bug guy – “eusocial” refers to extremely cooperative animals like bees, ants, and termites. Individuals sacrifice themselves for others.  Non-breeders help with childcare.  The colony seems more intelligent than its members.

Alexander proposed that a eusocial mammal could evolve if the animals were small compared to their food sources, and if they lived in underground burrows that could be expanded easily and defended by a small percentage of the colony.

After the lecture, an audience member mentioned that this “hypothetical eusocial mammal” sounded a lot like the naked mole-rat.  Alexander was introduced to Jennifer Jarvis, who had studied individual naked mole-rats but not their social lives.  Alexander and Jarvis collaborated to write The Biology of the Naked Mole-Rat.

Eliot Weinberger condensed this 500-page textbook into his 3-page essay, “Naked Mole-Rats.”

#

Like us, naked mole-rats are both good and bad.  They are cooperative.  They are affectionate.  They are always touching.  When they meet strangers, they fight to the death.  When a breeding female dies, many other females regain fertility and the colony erupts into civil war.

Weinberger wrote that naked mole-rats “are continually cruel in small ways.”  But they are outdone by naked apes. 

#

For a research paper published in 2008, Thomas Park and colleagues found that being pinched by tweezers causes naked mole-rats pain, but injection with caustic acid does not.

“We tested naked mole-rats in standard behavioral models of acute pain including tests for mechanical, thermal, and chemical pain.  We found that after noxious pinch or heat, the mole-rats responded similarly to mice.”

“In contrast to the results using mechanical and thermal stimuli, there was a striking difference in responses to strong chemical irritants.  Two chemicals were used – capsaicin from hot peppers and hydrochloric acid – which normally evoke very intense pain in humans and other animals.  Injection of either rapidly evoked intense licking and guarding behaviors in mice.”

“In contrast, naked mole-rats showed virtually no response.”

#

Perhaps you worry that acid-resistant naked mole-rats could conquer the world.  Fear not.  A form of kryptonite exists.  Injection of an 11-amino-acid signaling peptide allows acid to hurt naked mole-rats just as much as it hurts mice.  Or us.

Half a dozen animals were subjected to each treatment.

#

Naked mole-rats don’t die from cancer. 

They should.  Their cells, like ours, are copied from copies of copies.  Errors compound.

Some errors are particularly deadly.  Our cells are supposed to stop growing when they touch.  They are supposed to commit suicide when old.  But the instructions telling a cell when and how to kill itself can be lost, just like any other information.

This is cancer.

In cancer, a single cell proliferates at the expense of others.  A cancer cell claims more than its fair share of space.  It commandeers nutrients.  This cell, and its progeny, and its progeny’s progeny, will flourish. 

Then the scaffolding creature dies.  Then the cancer cells die, too. 

But every cell that isn’t an egg or sperm is terminal anyway.  In the colony of our body, most cells are non-breeding members.  From a cancer cell’s perspective, it has nothing to lose.

#

We develop cancer often.  With each passing day, we produce about 100 billion new cells.  Each time we produce a new cell, all 3 billion letters of our genome must be copied. 

The enzymes that copy our genome make one mistake every billion letters.  Each cell division: three new mutations.  Each day: three hundred billion new mutations.

Some mutants are trouble. 

#

Our bodies kill cancer.  Your immune system – the same mess of mucous, inflammation, and goo that goes haywire during the flu – seeks and destroys renegade cells.  Your body is a fascist enterprise; white blood cells, its militarized police.

Chemotherapy does not kill cancer.  Chemotherapy means flooding the body with poisons that stop all cells from reproducing.  With luck, if the spread of cancer is slowed, your immune system can kill it before it kills you.

In naked mole-rats, cancers always grow as slowly as if the rodents were receiving chemo, allowing their immune systems to squelch cancers at a leisurely pace.  Their cancers are slowed by a heavy sugar called “hyaluronan,” which is packed so tightly into the space between cells that there is no room to grow.

In 2013, biologist Xiao Tian and colleagues wrote that “naked mole-rats may have evolved a higher concentration of hyaluronan to provide the skin elasticity needed for life in underground tunnels.  This trait may have then been co-opted to provide cancer resistance and longevity.”

They became impervious to cancer almost by mistake.

#

The record lifespan for a naked mole-rat in captivity is 28 years, 4 months.  The record-holder was nicknamed James Bond.  He was senior consort to his queen and continued rutting – and siring pups – up until the day he died.

Bond was dissected.  His cells showed extensive oxidative damage in their lipids, proteins, and DNA.  Bond should have been hobbled by age.  But time did not slow him down.

Science writer David Stipp described him as “a little buck-toothed burrower who ages like a demigod.”

#

Humans typically cease breeding long before we die.  From an evolutionary perspective, as soon as we stop having children, our fitness drops to zero.

And yet, we have long lifespans.  The dominant theory is an offshoot of “the grandmother hypothesis” – because we often care for grandchildren, there may have been evolutionary pressure to maintain good health until our grandchildren also reach reproductive age. 

With twenty-year generations, there’d be an incentive to survive until our sixties.

After that, perhaps our ancestors were no longer helpful.  And so we’ve inherited a propensity to decay.  Expensive medical interventions can preserve us longer, but once we pass our natural lifespans, brains and bodies weaken.

#

When scientists starve animals in the lab, it’s called “caloric restriction.”  This protocol extends lifespan in a wide variety of species.  Monkeys, mice, flies, and worms.  Ten-fold increases in lifespan have been observed.

Caloric restriction should extend the lives of humans, too.

There are unpleasant side effects.  Caloric-restricted mice spend their time staring at empty food bowls.  They are listless: barely moving, barely sleeping.  They live longer, but worse – and if they are fed slightly less, they die of malnutrition.

Frequent starvation in the wild may have caused naked mole-rats to evolve their prodigious longevity.

Naked mole-rats expand their colonies outward, searching for edible roots.  When they find a good root, they gnaw it carefully, attempting to keep the plant alive as long as possible.  But a colony of naked mole-rats eats faster than any plant can grow.  When the plant dies, the colony plunges into famine. 

#

Most eusocial animals carefully ventilate their homes.  Termites build giant pylons in the desert.  Although temperatures outside careen from 35 degrees at night to over 100 during the day, the interior of the mound remains a constant 87 degrees.  And the termites do not asphyxiate.  Their exhalations are swept away by circulating air.

Naked mole-rats burrow with less care.  They sleep in piles, hundreds of bodies lumped together underground.  Those near the center soon run out of oxygen.

We would die.

Most animals, deprived of oxygen, can’t fuel their brains.  Thoughts are expensive.  Even at rest, our brains demand a constant influx of energy or else the neurons “depolarize” – we fall apart.

Since the death penalty was reintroduced in the United States in 1976, we have killed eleven prisoners in gas chambers.  During the 1983 execution of Jimmy Lee Gray in Mississippi, officials cleared the observation room after eight minutes.  Gray was still alive, gasping for breath.  His attorney said, “Jimmy Lee Gray died banging his head against a steel pole in the gas chamber while reporters counted his moans.”

Gas chambers are pumped full of cyanide gas, carbon monoxide, or carbon dioxide.  Carbon dioxide is cheapest. 

#

With each breath, we inhale oxygen, burn sugar, and exhale carbon dioxide.  When we drive, our cars intake oxygen, burn gasoline, and exhaust carbon dioxide. 

In small amounts, carbon dioxide is beneficial.  Carbon dioxide allows plants to grow.  But when you put too much inside a chamber, somebody dies.  Put too much in the air worldwide and we all die.

The planet Venus was habitable, once.  Humans could have lived there.  Venus had a deep ocean and mild weather.

Through some fluke, Venus experienced a temporary bump in the amount of carbon dioxide in the air.  Carbon dioxide traps heat, which caused water to evaporate.  Clouds formed, which trapped more heat.  The cycle continued. 

Venus is now a fiery inferno.  The ground is bare rock.  Sulfuric acid rains from the sky.

#

Lab mice die in gas chambers.  Sometimes one mouse is set inside the plexiglass box; sometimes several mice inside a Chinese-food takeout container are gassed together.  A valve for carbon dioxide is opened; the mice lose consciousness; they shit; they die.

A naked mole-rat would live.  Unless a very determined researcher left the gas flowing for half an hour.  Or so found Thomas Park and colleagues – the same team that discovered that naked mole-rats dislike being pinched.  As they reported in 2017:

Human brains drink sugar.  We are like hummingbirds that way.  And our brains are very fussy eaters.  We are fueled exclusively by glucose.

Naked mole-rats are less particular.  Their minds slurp fructose to keep from dying.

#

Naked mole-rats are the most cooperative of mammals.  They are resistant to cancer.  Unperturbed by acid.  They age with the libidinous gracelessness of Hugh Hefner. 

They are able to withstand the horrors of a gas chamber.

And yet, for all these talents, naked mole-rats are easily tormented by human scientists.

.

.

.

Featured image from Wikimedia Commons.