Wednesday, June 10, 2015


In the spring of 1862, one year into the American Civil War, the Union troops pushed farther into Confederate territory along the Tennessee River. By April, they had already established camp near Shiloh and were awaiting reinforcements.

—On April 6, Confederate troops launched a surprise attack. Unionists managed to hold their ground until help arrived. Outnumbered by 10,000, the Southerners withdrew their troops.

—The Battle of Shiloh was fought over two long days, yet remains one of the bloodiest in American Civil War history, leaving more than 16,000 Union soldiers wounded and 3,000 dead. More than 23,000 casualties were reported on both sides. The Battle of Shiloh took place in a wet, swampy region. Wounded soldiers had to wait in the mud and foul water for two consecutive rainy days and nights for the medics to arrive.

As soon as dusk fell on the first night, soldiers noticed something strange. Their wounds were glowing a faint blue color in the dark. No one knew what it was or what it meant. When the men were finally taken to the field hospitals, the mysterious glow faded. But the strange events did not end there. Medics were dumbfounded to see that the soldiers whose wounds glowed the previous days showed a much better healing and survival rate than those whose wounds did not glow.

The mysterious blue light became known as the “Angel’s Glow.” Little was known about germs and infections at the time and the only explanation people could come up with was that the soldiers were touched by angels, it became part of the nation’s warfare folklore. That was until science proved it to be something more.

Photorhabdus luminescens is a bacterium with a high biocontrol potential. It can make insects sick and can kill pathogenic agents at the same time. What’s more, it is a luminescent bacterium that glows a soft blue in the dark. P. luminescens live in parasitic worms called nematodes, which feed on insect larvae. To do this, they burrow inside the larvae. Once inside the blood vessels, they throw up the P. luminescens, which release chemicals that kill the larvae and all other microorganisms, leaving the nematode and the bacteria to feed undisturbed.
The insect will glow a soft blue light that will lure other insects and potential preys. When they are done feasting, the P. luminescens reenter the nematode’s guts and they travel together to their next host. there are in fact three bioluminescent bacteria strains that produce antibiotics. These inhibit the growth of other bacteria that can cause infections, especially in open wounds.

The soil and conditions on the battlefield at Shiloh were excellent for nematodes to thrive in. Nematodes and their partners hunted down insect larvae that are naturally drawn to injuries. There was only one problem. P. luminescens can’t survive at normal body temperature. The rain and low nighttime temperatures in April were enough to make the soldiers suffer from hypothermia. A lower body temperature was sufficient to invite P. luminescens to burrow in their wounds. They infested the larvae, destroying any other pathogenic bacteria in the wounds, and releasing a surreal glow. The bacterium saved their lives. When the soldiers were transported to the field hospitals and their body temperature returned to normal, the bacteria died. For once, hypothermia played an important role in saving the soldiers’ lives.

A bacterial infection in an open wound often leads to a fatal outcome. But at the Shiloh battlefield, it was a matter of the right bacteria at the right time.


No comments:

Post a Comment