Some science behind the scenes

Bacteria

Lyall Watson – Heaven’s Breath
It is estimated that just a gram of fertile soil could house as many as 1000 million individual bacteria.  But the majority of these are locked into the soil cycle, where they are responsible for the formation of humus and for the breakdown of organic matter into essential nutrients.  Only a relatively small number of bacteria hold a watching brief, waiting for the occasional windfall that brings them a ripe apple, or a dead elephant to dispose of .  These are the spore bearers, the ones at the surface which most often become airborne and which like their city cousins, frequently do so on rafts of soil or vegetation…….

Dust devils whirl millions of bacteria high into the air and, once there, they are at the mercy of every stray breeze.  A large bacterial cell in a gentle but steady wind of just ten kilometres an hour, will travel over 10,000 kilometres before falling 100 metres back to earth.

 

Bill Bryson 

Some scientists now think that there could be as much as 100 trillion tonnes of bacteria living beneath our feet in what are known as sub-surface lithoautotropic microbial ecosystems -  SLiME for short.  Thomas Gold of Cornell University has estimated that if you took all the bacteria out of the earth's interior and dumped them on the surface, they would cover the planet to a depth of 15 metres – the height of a 4 storey building.  If the estimates are correct, there could be more life under the earth than on top of it. 

At depth microbes shrink in size and become extremely sluggish.  The liveliest of them may divide no more than once a century, some no more than perhaps once in 500 years.

 

Christian de Duve

Given an adequate supply of nutrients, a single bacterial cell can generate 280,000 billion individuals in a single day.

 

Bill Bryson

Scientists in Australia found microbes known as Thiobacillus concretivorans which lived in – indeed could not live without – concentrations of sulphuric acid strong enough to dissolve metal.  A species called Micrococcus radiophilus was found to live happily in the waste tanks of nuclear reactors, gorging itself on plutonium.  Some bacteria break down chemical materials from which as far as we can tell, they gain no benefit at all.  They have been found living in boiling mud pots and lakes of caustic soda, deep inside rocks, at the bottom of the sea, in hidden pools of icy water in Antarctica and 11 kilometres down in the Pacific ocean where pressures are more than a 1000 times greater than at the surface.  Perhaps the most extraordinary survival yet found was that of a streptococcus bacterium that was recovered from the sealed lens of a camera that had stood on the moon for two years.

 

Victoria Bennett

They are finding now that when they push probes into ocean vents so hot that the probes actually start to melt, there are bacteria even there.

Bill Bryson

About once every million divisions, the bacteria produce a mutant.  Usually this is bad luck for the mutant – for an organism, change is always risky – but just occasionally the new bacterium is endowed with some accidental advantage such as the ability to elude or shrug off an attack of antibiotics...........  any bacterium can take pieces of genetic coding from any other

 

Bill Bryson 

Microbes, including the modern version of cyanobacteria, supply the greater part of the plant's breathable oxygen.  Algae and other tiny organisms bubbling away in the sea, blow out about 150 billion kilograms every year.

 

Bill Bryson

You have a herd of about one trillion bacteria grazing on your fleshy plains – about a 100,000 of them on every square centimetre of skin.... 

There are trillions more tucked away in your gut and nasal passages, clinging to your hair and eyelashes, swimming over the surface of your eyes, drilling through the enamel of your teeth.  Your digestive system alone is host to more than 100 trillion microbes, of at least 400 types...

Every human body consists of about 10 quadrillion cells, and is host to about a hundred quadrillion bacterial cells.  They are in short, a big part of us.  From the bacteria's point of view of course, we are a rather small part of them.........

Bacteria, never forget, got along for billions of years without us. Without them nothing would rot.  They purify our water and keep our soils productive.  We depend totally on bacteria to pluck nitrogen from the air and convert it into useful nucleotides and amino acids.

 

Bill Bryson

In 1952, penicillin was fully effective against all strains of staphylococcus bacteria....  by the early 1960s the US Surgeon General William Steward felt confident enough to declare 'The time has come to close the  book on infectious diseases.  We have basically wiped out infection in the United States'.  Even as he spoke, however, some 90% of those strains were in the process of developing immunity to penicillin.  Soon one of those new strains, called methicillin resistant staphylococcus aureus, began to show up in hospitals.  Only one type of antibiotic – vanomycin – remained effective against it, but in 1997, a hospital in Tokyo reported the appearance of a strain that could resist even that.

 

Bill Bryson

As Margala and Sagan put it, all bacteria swim in a single gene pool.  Any adaptive change that occurs in one area of the bacterial universe can spread to any other.  It's rather as if a human could go to an insect to get the necessary genetic coding to sprout wings or walk on the ceiling.  It means that from a genetic point of view bacteria have become a single superorganism – tiny dispersed, but invincible

 

Bill Bryson

Further research has shown that there is or may well be a bacterial component in all kinds of disorders – heart disease, stomach ulcers, asthma, arthritis, multiple sclerosis, several types of mental disorders, many cancers including stomach cancer.

Observations

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