8/8/2019 Microbe Moments

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Magni f icentMicrobe Moment s

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Bacteria have been here for billions of years, but it took humankind along time to find out about them. First we needed the tools to study them. What we have learned about bacteriawhat they look like, how they work, what effect they have on our lives and the earth on whichwe liveis information gathered over less than 400 years. Lets turn thespotlight on some of the heroes in microbiology, the study of bacteriaand other microscopic forms of life.

Robert Koch (coke) picks up where Leeuwenhoek lefclaiming bacteria could cause disease. But no one is buyingerm theory of disease. The doubters insist that tiny thibacteria couldnt possibly sicken larger ones like people.

Koch says not only do bacteria cause disease, but specicause specific diseases. He sets out to find out which oneresponsible for some of the worlds fiercest killers, going and India.

In 1876, he makes his first major discovery:Bacillus anthracis ,the bacterium that causes anthrax, a devastating disease ocattle. He goes on to discover the bacteria that cause tubeand cholera.

French scientist Louis Pasteur is one of Kochs scientific allies and one of the most brilliant people of his time. He figures out that heating milk willkill the bacteria that cause it to spoil. The process, called pasteurization, isstill used today.

Later, Pasteur takes the germ theory a step further by developing a way toprevent bacteria from causing disease. Its called vaccination, and Pasteurdiscovers it by accident. He notices that bacteria weaken after a fewgenerations and the weaker the bacteria, the less likely they are to make peoplesick. Pasteur takes the daring step of injecting some very weak bacteriathekind that causes rabiesinto a boy who had been bitten by a dog with rabies.(Luckily for us all, the boy lives.)

Why does vaccination work? Even though the weakened bacterium wontcause illness, the immune system marks it as an enemy and puts it on theMost Wanted list. The next time the invader turns up in the bodyit couldbe years laterthe immune system spots it immediately and knocks it out.

Among the vaccines Pasteur develops are those against the bacterialdiseases anthrax, cholera, and diphtheria.

Paris, France, 1862 Paris, France, 1862

Delft, Holland, 1674 Delft, Holland, 1674

Wollstein, Posen, Germany, 1876 Wollstein, Posen, Germany, 1876

ntony van Leeuwenhoek(LAY-ven-hook) a maker of mensclothes, wants to closely examinefine fabrics. So he makes apowerful lens that can magnify things up to 300 times their size!This was not the first microscope,

but it was more powerful thanany that had been made before.Leeuwenhoek starts looking at

other things besides cloth. A hairfrom his beard drops of blood pond water spit. Hesamazed at what he sees: littleanimals. He calls themanimalcules and today wecall them one-celled organisms,or microbes.

Leeuwenhoek makes drawingsof everything he sees. In 1674, hepublishes his first report, whichdescribes red blood cells. Later,he describes bacteria: bacilli,cocci, and spirilla.

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Fanny Hessesmicrobiologist husband, Walter,has a problem: bacteria in the lab are grown in a sortof broth, making it hard to see and study growing

colonies. Walter says he needs something bacteriacould grow on, not in.In Fannys kitchen is a substance called agar-agar,

which cooks used to make jams, jellies, andpuddings. When dried agar is mixed with water,boiled for a while, and left to cool, it solidifies into arubbery mass. Fanny suggests pouring it into a petridish to have the perfect place to grow bacteria. Itsstill used for that today.

MY FAVORITEMISTAKESome of the most imposcientific discoveries were made by accident. Write ajournal entry, a short story, or a dramatic sketch abouan accidental discovery you or someone your age hasmade. The situation can be fictional. It can even befunny. Just be sure to include the outcome: How did accident change things?

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Germany, 1881 Germany, 1881

British chemist AlexandeFleming looks at someforgotten petri dishes inwhich he had been growibacteria. Theyre uselessTheyve been exposed toair and are probablycontaminated by othermicrobes. In fact, theyrecovered with mold. He isabout to toss them out whsomething catches his ey Where there is mold, therno bacteria. He soonconcludes that mold haskilled the bacteria.

The mold is penicillin,extremely common fungu that grows on bread andother food, including agaagar. It can stop many kin

of pathogenic bacteria dein their tracks by damagi the bacterial cell wall,which strips the cell ofprotection from the outsiIt is the first antibiotic evdiscovered.

London, England,1928 London, England,1928

While Koch and Pasteur are investigating bacterial diseases,

British surgeon Joseph Lister has another problem: His patients

are dropping like flies! Even after successful surgery.

Lister believes the germ theory of disease and takes steps.

His idea is to use carbolic acid, which he knows can kill

bacteria, on everything that touches a patient during surgery.

He sprays it on his scalpel and other instruments, he sprays

his hands, he sprays the bandages. He even sprays carbolic acid

directly in the wound.And guess what? It works. The culprit is sepsis, infec

tion

caused by bacteria that get inside the body when the surgeon

cuts through the skin. Before Lister started his antiseptic

campaign in 1865, 50 percent of his surgical patients died.

Afterwards, deaths were down to 15 percent. Today, patients

are even less likely to develop a life-threatening infection as

a result of surgery.

London, England, 1865 London, England, 1865