Fleming_Florey_and_Chain.ppt

7/28/2019 Fleming_Florey_and_Chain.ppt

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FLEMING,

FLOREY ANDCHAIN:THE DISCOVERY

AND DEVELOPMENTOF PENICILLIN

Edexcel IGCSELesson 5


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What is Penicillin?

Penicillin is an antibiotic. Antibiotic literally means against life

but antibiotics only kill life that isharmful to living creatures, i.e.

bacteria. A bacterial infection is caused by

millions of tiny bacteria that are tryingto survive and multiply in the body. Anantibiotic attacks and kills thesebacteria.

Before the development of penicillin,many people suffered and died frombacterial infections that are no longer

considered dangerous today.


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So did Fleming actually discoverpenicillin?

Penicillin is made from a mouldcalledpenicillium. This mould wasfirst discovered in the early 19thcentury by John Sanderson who

found that very little grew near it. In the 1880s, Joseph Listernoted

these observations and wrote to hisbrother to say that he intended totry penicillin on infected wounds.

Lister successfully treated anurse with an infected wound withpenicillin, but did not leave anynotes on the case and apparently

did not continue his research inthis area.


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Who was Alexander Fleming?

Alexander Fleming wasborn in Ayrshire, Scotland,in 1881. He was the son of

a farmer. When he was 13, he

moved to London to livewith his older brother.

After graduating from theUniversity of London, hebecame a bacteriologist atSt. Marys Hospital in the

city.


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The great re-discovery ofpenicillin! It was in the laboratory of St. Marys Hospital in 1928 that

Fleming rediscovered the properties of penicillin. This sourcecomes from a biography, The Life of Sir Alexander Fleming,written in 1963. It describes when Fleming was visited by hisfriend, Pryce.

Fleming was in his little laboratory as usual, surroundedby innumerable dishes. The cautious Scot disliked being separatedfrom his cultures before he was quite sure there was nothing moreto be learned from them... Fleming took up several old cultures andremoved the lids. Several of the containers had been contaminatedwith mould... As soon as you uncover a culture dish, he said toPryce, something tiresome is sure to happen. Things fall out of the

air.

Suddenly he stopped talking, then, after a moments

observation, said... Thats funny...On the cultures at which hewas looking there was a growth of mould, as on several of the

others, but on this particular one, all around the mould, the


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So what did the mould looklike?

The mould Penicillium Notatum, shown growing in a Petri dish, and inclose-up


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How had it got into Flemings

dish? On investigation, Fleming found that penicillin bacteria

had got on to the dish, perhaps blown into his lab throughan open window. The penicillin was killing thestaphylococci.

Whether the account we just read it how it reallyhappened, we cannot be sureeven Flemings ownaccounts of how it happened varied! Does that matter?

The important point is that Fleming identified the mouldand saw its significance that penicillin could be appliedto or injected into areas where there were penicillin-sensitive microbes .

However, Fleming did not have the facilities or thesu ort to develo and test his idea that enicillin could


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Think!

Why is Fleming usually thought of as thediscoverer of penicillin?

Why do you think that so many peopleobserved the power of penicillin but did notdevelop it as a cure?

Now read your textbook, pp42 43 to see howpenicillin came to be developed.


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Florey and Chain

It was the Second World Warwhich finally brought about thesuccessful development ofpenicillin.

In the 1930s two Oxfordscientists, Howard Florey andErnst Chain, became interestedin Flemings 1929 paper onpenicillin.

In 1939 they assembled a teamof pathologists, chemists andbiochemists, and three daysafter the outbreak of warFlorey asked the British

government for money to fundthe teams research into

Howard Florey (left)and Ernst Chain.

Do you think this was agood time for Florey toapproach the governmentfor money into this kind ofresearch? Why?


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The development of penicillinStage 1:Growing the penicillin

This was a combination of the latest freeze-drying technology and some much more traditionalequipment: thousands of milk bottles (in which to grow the bacteria), milk churns, a dog bath and a

hand pump! From this, the team were able to gather a few grams of pure penicillin.

Stage 2: Testing penicillin on animals

There was enough penicillin to test it on eight mice. They were injected with a deadlybacteria (streptococci). Four of the mice were then given penicillin. 24 hours later themice which had not been injected with penicillin were dead. Those who had been

injected were healthy.

Stage 3: The first human trial of penicillin

By 1941 the team had enough penicillin to test it on a human. The patient had terrible abscesseswhich had spread from his mouth to his scalp, eyes, arm and even his lung. He was going to die there was nothing to lose by trying penicillin. After four days of treatment he was much improvedand was sitting up in bedpenicillin worked. However, they did not have enough, and after five

days the supply ran out the patient relapsed and died.


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Production continues... but not in greatquantities!

Although this first patient still died, it was clearthat penicillin was a powerful drug. Productionremained painfully slow, but as new batches wereproduced, two more patients were successfully

treated.

In August 1942, Fleming himself used penicillin tosuccessfully treat a friend who had meningitis.

But the war was producing thousands ofcasualties penicillin needed to be massproduced if lives were to be saved.


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Steps to Successful MassProduction

June 1941:Florey travelsto US to try to

get drugcompanies to

developpenicillinnot muchinterest.

December1941:

US enters thewar

1942:

US governmentgives $80million to 4

drug

companies tofind a way to

mass producepenicillin.

1943: Massproduction

began. Penicillinfirst used by

British army inNorth Africa.

June 1944:Enough penicillinis available totreat all the

casualties of D-Day.

1945: US Armyusing 2 million

doses of penicillina month

After WW2:Penicillin made

available for civilianuse.


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How important was penicillin?

It is estimated thatwithout penicillin,another 12-15 per cent

of wounded Alliedsoldiers would have

died of infections.

Penicillin also roughlyhalved the average

time the Allied

wounded spent in

hospital.


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How important was penicillin?

Penicillin was a miracle drugwhen it was first developed. Itcould treat a wide range of

infections and diseases,including streptococcus, scarletfever, syphilis and gonorrhoea.

In 1945, Fleming, Florey andChain were jointly awarded theNobel Prize for Medicine for theirwork on penicillin.


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Penicillin why then?

On your own slide, draw a spider chart whichshows the different factors which influencedthe discovery of penicillin.

It should help you to think about why penicillinwas finally mass produced in 1942-1945, andnot before.

Try to link any factors which you think areinter-connected.


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So which factor was mostimportant?

So can we answer our question why waspenicillin mass produced in 1942-1945 and notbefore?

Do you think any one factor was particularlyimportant to the development of penicillin?

Who do you think deserves the credit for thediscovery of penicillin?


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Homework

1. What is penicillin?

2. What part did chance play in the discovery ofpenicillin?

3. How did war influence the development of

penicillin?4. How did governments help in the mass

production of penicillin?

5. What other factors were important in thedevelopment of the drug?

6. Why was penicillin mass produced in 1942-1945and not before?

7. Who deserves most of the credit for Penicillin?

8. Add the major steps in the

discovery/development of penicillin to yourongoing timeline

Fleming_Florey_and_Chain.ppt

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