Can Science Produce Life?: By RUTHERFORD PLATT

Courtesy: Medical Miracles, from Readers Digest 1981. November.

From the frontiers of science and the far horizons of personal courage, these stories of medical triumphs and miracles will reaffirm your faith in the awesome powers of the human spirit. Dramatic victories and human triumphs.

Selected and edited by the editors of Readers Digest

For years scientists have carried on a wave of unprecedented laboratory experiences to test their theories of how life on Earth began.  The results have been amazing.  Retracing the probable steps by which the raw, lifeless elements of space became organic matter, they now have produced primitive cell-like structures that have many of the properties of living cells.  Here is the dramatic story:

When Planet Earth was born it slowly cooled to form a hardened crust of black volcanic rock.  In time, masses of silicon mixed with mineral elements were squeezed to the surface by the pressures of internal fires, and crystallized as big islands of granite, which formed the foundations of continents.  The whole crust heaved and bulked, cloudbursts drenched the rocks, and sterile water collected in wide depressions to form the earth’s first seas.  Countless volcanoes and fissures continuously gushed methane, steam, ammonia and perhaps carbon dioxide, to give the earth its first atmosphere.  That ‘air’ contained the four chief elements of life—carbon, oxygen, hydrogen and nitrogen.  But they were in the form of gases deadly to present-day life.  Moreover, the atmosphere was flooded with ultraviolet radiation and stabbed by incessant lightning.

How, in this elemental turmoil, did life on earth begin?  Many have tried to supply the answer.  Among the first was Anaxagoras of Greece, who in the fifth century B.C. declared that life comes down to earth in raindrops, in the form of spermata [little seeds].  Came the 20th century, and the origin of life was still a mystery.

Then in 1924 the Russian scientist A.I.Oparin stated that life might have arisen out of inanimate matter in a prolonged process of ‘preorganic evolution.’  He showed how, in theory, atoms of carbon, oxygen, hydrogen and nitrogen could have formed molecules basic to life, even under the raw, inhospitable conditions of the primordial earth—and how self-reproducing clusters of these molecules might have adhered together and then evolved toward more complex forms.

Three years later the English biochemist J.B.S.Haldane wrote that although such substances would be destroyed by microorganism, “before the origin of life they must have accumulated till the primitive oceans reached the consistency of hot, dilute soup.”  And when the ultraviolet light radiated the surface of this soup, inorganic compounds would have been converted into organic molecules—molecules containing carbon.  At once time scientists believed that only living things could produce such organic molecules.

By the 1050s the scene was shifting from the theorist’s armchair to the laboratory, where scientists were striving to demonstrate that the molecular constituents of life could have emerged under primordial condition.

Using the cyclotron at Berkeley to create high-energy particles to represent cosmic rays, Dr. Melvin Calvin of the University of California bombarded a mixture of carbon dioxide and water vapor; ingredients he thought likely to have been present in the earth’s ancient atmosphere.  Some organic compounds were formed.

Dr. Harold C. Urey, atomic scientist then at the University of Chicago, reasoned that methane, ammonia and hydrogen were probable constituents of the original atmosphere.  What would happen, he wondered, if these raw lifeless substances were placed in a flask and then stabbed repeatedly by electric flashes to represent lightning?  In 1953 his student Stanley L. Miller performed this now classic experiment.  To their delight, they found that amino acids had been formed.

Amino acids are the building blocks of protein and hence of all life.  They are also believed to have been involved in the first stage of the evolution toward life.  The theory is this:

The colossal retort of the primordial earth must have yielded myriads of molecules as ephemeral as bubbles.  But, because of their peculiar molecular structure, the molecules of amino acids are especially stable.  The four elements of life—carbon, oxygen, hydrogen and nitrogen—are assembled in every amino-acid molecule into two opposing groups so well-matched in their electrical charges that they are stabilized like wrestlers locked in equal combat.  Thus the tenacious amino acids could have survived in the chaos to become an early link between no-life and life.

In experiments that followed, a surprising fact turned up.  The basic molecules of life could also have been produced by many other forces in those fierce, elemental times, including X rays, cosmic rays, ultraviolet light and volcanic heat.

After the creation of amino acids, two even larger problems remained.  Giant protein molecules, discovered everywhere in living things, are made of long chains of amino acids.  How did the amino acids get hooked up into these long chains?  And then how did these twisted protein giants turn into living cell?

Giant proteins are fantastically elegant structures—“the noblest piece of architecture produced by nature” in the opinion of biologists.  One molecule of the vital protein of blood, hemoglobin, for example, has 8954 atoms fitted together in a dazzling pattern.  The problem is that all the complicated proteins in life around us—living cells create those, which make flesh, blood, bone, hair, eggs, milk, seeds, and feathers—.  Those living cells in turn are made of protein.  How could protein be created in the first place, when there were no living cells?

This question is puzzling many scientists around the world.  No one has yet developed a foolproof theory that explains which steps came first of what triggered them.  One line of reasoning, first put forward by Dr. George Wald of Harvard, is that there may be conditions occurring in nature in which amino acids might themselves furnish the answer.  And so they did—quickly and beautifully—when the stage was set for them by Dr.Sidney W. Fox, then of the Institute of Molecular Evolution in Miami, Florida.  The “miracle” occurred when amino acids were permitted to dry out.  The thinking was that solutions of amino acids, billions of years ago, had puddled in warm, dry spots.  What would happen to such solutions today if the water was allowed to evaporate?  The scientists who watched this experiment saw a marvelous event.

As the spot on the warm test tube dried, its amino acids formed long, submicroscopic thread-like structures.  These chains some with hundreds of little molecules jointed end to end, were named proteinoids.  The sum of their electric energies endowed them with power to bend and fold!

There are 20 kinds of amino acids common to the proteins of life, and the precise order in which these are lined up in the chains spells what their protein creates—flesh of bone, hair of feather.  The scientists have been able to manufacture all these amino acids under presumed primordial conditions.  Dr. Kaoru Harada was able to synthesize 14 in a single experiment.

So the answer to one question is found.  Amino acids by themselves can produce primitive protein-like material under certain conditions—no need for a cell to help them.

Still, the final question remains.  How could these proteins from a living cell, with its millions of atoms and molecules carefully arranged in a precise pattern?

The primitive proteins came long before living cells appeared.  The precisely ordered proteins of present-day plants and animals would have acquired their amino-acid arrangement in the course of many millions of years of evolution.  Dr. Calvin estimated that molecular life must have evolved for two billion years before the first living cells appeared.

Duplicating this great leap, making a whole living cell in the laboratory, may take a while.  But it now appears that we’ve begun.  The most striking experiment, which has produced crude cell-like spheres that maintain their identity and are capable of dividing themselves, is truly fantastic and has taken us a giant step along the pathway toward understanding the origin of life.

Again, Dr. Fox did the experiment.  To reconfirm his laboratory findings, he climbed up the broad slope of a cinder cone in Hawaii, looking for spots where conditions might have permitted primitive proteins to form in the pre-life world.  He was surprised to discover that large areas of the cone were oven-hot just beneath the surface.  Might not this warm primitive earth have been the womb of the molecules of life—where they could bake and boil, before being washed through the loose lava by a cloudburst and so into the sea?  What would this have done to the elemental amino acids?

Dr. Fox took hunks of lava back to the laboratory and placed on them amino acids coined from methane, ammonia and water.  With everything sterilized to avoid contamination, he baked this concoction for a few hours in a glass oven at 338-degree F., the temperature he found four inches under the surface of the cinder cone.  When the materials cooled, a brown, sticky residue was left clinging to the lava.  He then deluged the lava with sterile water, and a brown soupy liquid resulted.

This unpromising stuff turned out to be very exciting.  As seen through an ordinary optical microscope a wonderful galaxy of spheres swarmed across the field of vision.  The amino acids had first united to make proteinoids—and then these had combined to form little spheres!  Dr.Fox named these fascinating strangers ‘microspheres’.n  they looked like, in many ways behaved like, and were the same size as certain simple bacteria, and they clung together in chains as do the one-celled blue green algae.  Bacteria and blue-green algae are two of the most elementary forms of life that exist on earth.

Although these spheres are not true cells—they have no DNA genes and they are simpler than any contemporary life—they do possess many cellular properties.  They have stability: they keep their shapes indefinitely.  They stain in the same way as the present-day protein in cells, an important chemical test.  But the real significance of these micro spheres is that scientists did not synthesize them piece; they simply set up the right conditions—and micro spheres produced themselves.

In the meantime, scientists working independently in other laboratories are making DNA and other essential constituents of the living cell could have formed.  It becomes hard to avoid the premise that life is inherent in matter, and that life will exist on other planets whenever the conditions are right.