Frontiers of Science: Living Lights

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Living Lights

During the Arab-Israeli Six-Day War of 1967, a midnight patrol of Israeli soldiers along the shore of the Sinai Peninsula spotted a faint green light hovering in the waters of the Red Sea just beyond a coral reef. Thinking that they had surprised a team of enemy frogmen, they fired explosive shells into the glowing area. The result, however, was not a spoiled enemy mission, but a beach strewn with the bodies of many small dark fish, from whose heads shone pairs of strange green lights.

What had fooled the Israeli soldiers was a school of flashlight fish, little known inhabitants of dark underwater caves and crevices that come to the surface of the sea on dark, moonless nights to forage for small organisms on the reef’s edge. Their sources of light are packets of a very unusual type of bacteria, billions of them in each packet, that give off a steady green glow. Located just under their eyes, they are used quite effectively by the fish as “headlights.” In fact, the fish can even turn them on and off by either blinking to cover them with an “eyelid” or by rotating them into protective pockets like the headlights of some automobiles.

The phenomenon of light production by living organisms is referred to by scientists as bioluminescence. Although there are many examples of it in the animal world, such as the familiar firefly and many marine organisms—sponges, corals, clams, snails, and squids—it is a particularly well-developed trait of many bacteria. Prior to 1978, however, the only known bacteria to exhibit bioluminescence were species that lived in the sea. But now, through the work of two scientists at the University of California at Berkeley, it is known that some types that reside on land also possess this strange characteristic.

The scientists who made this discovery were studying a species of worm that infects certain insects. When they took a container of dead insect larvae into their darkroom to photograph them, they observed an eerie glow coming from their lifeless bodies. Upon closer inspection, they determined that the glow came from millions of bacteria infecting the insects. These bacteria originally came from the worm that burrowed into the insects’ bodies. When the insects are first attacked by the worms, they are not killed. It is only following the discharge of the bacteria into their bodies by the worms that they are brought to their unhappy end. Then, new worms develop inside the dead insects and set about to devour the glowing bacteria and move on to a new victim.

But why should we be at all concerned about bioluminescent bacteria? One reason is that these organisms, particularly the ones that live in association with flashlight fish, exist in a very pure culture. That is to say, they are not contaminated with other types of bacteria living among them. Combining this fact with recent advances that have allowed scientists to alter the internal makeup of bacteria so as to enable them to produce important chemicals, such as the insulin so desperately needed by diabetic persons, scientists could use the presence of light coming from certain bacterial cultures as an indication that the cultures were free of any contamination.

Even more strange than the case of the glowing bacteria, perhaps, is the case of bacteria that turn on light bulbs. Due to the special characteristics of a purplish-red pigment contained in their cells, these bacteria can actually generate electricity. And recently, a scientist at the University of California’s Lawrence Berkeley Laboratory has produced a packet of them that can keep a tiny bulb lit for over an hour and a half. He envisions being able to eventually harness their unusual capabilities to desalinate seawater, to concentrate valuable metals or harmful chemicals from lakes, oceans, and sewage water, and to provide a living solar battery.

So the next time you read the creation story in the Bible or the Pearl of Great Price and you come to the part where Heavenly Father says, “Let there be light,” remember that there are more lights than just sun, moon, and stars. These amazing living lights are also creations of our Heavenly Father, and they are no less marvelous or important in their own spheres of activity. They, too, can perform a great service for humanity.

Pork Sausage Patties and Mormon Gravy

2 pounds pork sausage

3 tablespoons water

1/3 cup flour

3 cups milk

salt, pepper, and paprika

Shape sausage into a dozen 3″–4″ patties about 1/2″ thick and place in two cold skillets. Add water, cover, and cook over medium heat for 3 minutes. Pour off all but about 1/3 cup of drippings. Cook patties over medium low heat on both sides until well done. Remove patties to plate and keep warm.

Mix flour with drippings in skillet and cook over low heat until slightly browned. Remove from heat, add milk, and stir until smoothly blended into flour. Return to heat and cook over medium heat, stirring until mixture is thick and smooth. Add salt and pepper to taste. Add paprika. Mormon gravy can be served on baked potatoes, biscuits, cornbread, johnnycake, pancakes, or waffles.

Pioneer Lettuce Salad

1 head lettuce

1 cup whipping cream

1/4 cup vinegar

1 teaspoon sugar

1/4 teaspoon salt

Cut lettuce into wedges or shred. Whip cream and blend with vinegar, salt, and sugar. Serve over lettuce.

Honey Candy

2 cups honey

1 cup sugar

1 cup cream

Combine ingredients and cook slowly until candy reaches hard-ball or light-crack stage when tested in cold water. Pour onto buttered platter. When cool enough to handle, grease or butter hands and pull until candy is a golden color. Cut into pieces.

[illustrations] Illustrated by Shauna Mooney

[illustration] 1. Comb jellies’ eight rows of combs emit greenish flashes every few seconds, giving the sea a luminosity at night.

[illustration] 2. A flashlight fish, known scientifically as Photoblepharon palpebratus, vividly displaying the packet of bioluminescent bacteria that it carries just under its eye.

[illustration] 3. Light-producing organs or photophores are on either side of the deep-sea hatchet fish’s belly.

[illustration] 4. Water movement stimulates the noctiluca to produce a feeble light that is visible only when combined with the lights of masses of noctilucas with which it lives.

[illustration] 5. The 350 luminous organs of the viperfish help to attract prey into its fearsome-looking mouth.

[illustration] 6. Several species of the cardinal fish possesa internal organs inhabited by luminous bacteria.

[illustration] 7. Luminous organs under the jaw of the pinecone fish contain phosphorescent bacteria that glow. (NOTE: While the light sources of numbers 1, 3, 4, and 5 are not produced by bacteria, they are still examples of some of Heavenly Father’s other living lights.)

[photo] A photograph of several wax moth larvae taken in complete darkness. The larvae are made visible by the bioluminescent bacteria that inhabit their bodies. (Photo Curtesy of Dr. G. M. Thomas of the University of California at Berkeley, who together with codiscoverer Dr. G. O. Poinar has suggested that the bacteria be named Xenorhabdus luminescens.)

[illustration] Illustrated by Shauna Mooney