Name: 世界を変えた事故-アリソン・ラムゼイとメアリー・スタイク (The accident that changed the world - Allison Ramsey and Mary Staicu)
Uploaded: 2021-01-14T08:40:38.000Z
Duration: 4 min 51 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

London, 1928: a group of mold spores  surf a breeze through a lab.

They drift onto a petri dish,  and when they land,

This lab belongs to Alexander Fleming,  a Scottish scientist

investigating the properties  of infectious bacteria.

At this time,  Fleming is away on vacation.

When he returns, he finds  a colony of mold growing on a petri dish

he'd forgotten to place in his incubator.

And around this colony of mold  is a zone

completely and unexpectedly  clear of bacteria.

Fleming came to realize that the mold  was secreting some kind of compound

The mold was a species  in the Penicillium genus,

so Fleming dubbed  the antibacterial compound “penicillin.”

What Fleming stumbled upon  was a microbial defense system.

The penicillium mold  constantly produces penicillin

such as nearby bacterial colonies  that might consume its resources.

Penicillin destroys  many types of bacteria

by disrupting synthesis  of their cell walls.

These walls get their strength  from a thick, protective mesh of sugars

that are constantly being  broken down and rebuilt.

Penicillin binds to one of the compounds  that weaves this mesh together

and prevents the wall from being  reconstructed at a critical phase.

Meanwhile, penicillin stimulates  the release of highly reactive molecules

Eventually, the cell's structure  breaks down completely.

This two-pronged attack  is lethal to a wide range of bacteria,

whether in petri-dishes,  our bodies, or elsewhere.

It's not, however,  harmful to our own cells,

For a decade or so  after Fleming's discovery,

penicillin remained  a laboratory curiosity.

researchers figured out how to isolate  the active compound

They then went on to win  the Nobel Prize for their work.

Teams at Oxford and several American  drug companies continued development,

and within a few years  it was commercially available.

Penicillin and similar compounds quickly  transformed the treatment of infections.

they remain some of the most important,  life-saving antibiotics used in medicine.

However, the more we use any antibiotic,  the more bacteria evolve resistance to it.

some bacteria produce compounds  that can break down the key structure

that interferes with cell wall synthesis.

more and more bacteria  have evolved this defense,

against a growing number  of bacterial infections.

This means it's essential that doctors  not overprescribe the drug.

Meanwhile, 5 to 15% of patients  in developed countries

making it the most commonly reported  drug allergy.

However, the vast majority— over 90%— of people

who think they're allergic  to penicillin actually are not.

Many patients acquire the allergy label  as children,

when a rash appears after they're treated  for an infection with penicillin

while the more likely culprit  is the original infection,

or a reaction between the infection  and the antibiotic.

where our immune systems  mistake penicillin for an attacker,

do occur rarely  and can be very dangerous.

So if you think you're allergic  but don't know for sure,

They'll complete an evaluation  that'll confirm

Even if you do have a penicillin allergy,

your immune cells that react to the drug  may lose their ability to recognize it.

In fact, about 80% of people  who are allergic to penicillin

This is great news for people  who currently identify

the drug may one day save their lives,  as it has done for so many others.

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世界を変えた事故-アリソン・ラムゼイとメアリー・スタイク (The accident that changed the world - Allison Ramsey and Mary Staicu)

constantly

essential

phenomenon

immune