1. WHAT
ARE MICRO-ORGANISMS
Every
winter people start sneezing, coughing, getting sore throats and runny noses.
For many years the causes of this remained a mystery. it was like some
mysterious entity came into our body. "Pepito, ponte el abrigo, que te va
a coger el frío!" This expression (you are going to catch a cold) is a
good example. People thought that The Cold could actually cause these problems.
With
the invention and improvement of microscopes scientists were able too see the
world of the very little, and discover that there were things, tiny tiny things
where before we saw nothing. Look here, here,
or here.
Thanks
to this discovery we learnt that diseases were caused not by mysterious
elements, but by tiny little creatures than entered our bodies, reproducted in
our bodies, spread all around our bodies, and acted upon our organs.
This
discovery was good news because if we could see them, we could study them and
we could learn how to destroy them, or at least, if we couldn´t destroy them,
prevent coming in contact with them.
These
creatures received the name of micro-organisms, microbes, or germs. Micro is
a Greek prefix (μικρός) pronounced mikrós, that means small.
We now
know they are responsible for ilnesses such as the typical winter cold
(resfriado), mumps (paperas), chickenpox (varicela), smallpox (viruela),
measles (sarampion), sore throats, and several more serious infections.
To
learn more about micro-organisms: Check
this out!!!!!!!!!
2 TYPES
OF MICRO-ORGANISMS
We
classify microbes into 3 groups.
BACTERIA
VIRUS
FUNGI
Bacteria have
much in common with normal macro-organisms like us. They live, breathe, eat,
grow, reproduce,
and die.
*
Viruses are
quite mysterious and strange. We think they are not alive because they don´t
eat, they don´t breathe, they don´t grow, but they reproduce!!! The virus
reproduction is also quite unusual: it does not happen between
viruses!!! A virus needs one of your normal body cells. It will trick the cell
to go inside of it, and when the cell is making a new DNA chain, that will form
a new normal body cell... A second trick. It introduces its virus DNA, so your
poor normal body cell CREATES A NEW VIRUS!!!!
This is
complicated. but so that you understand it is like when your mum and dad mixed their
DNAs to have you, a boy or a girl, a mixture of your mum and dad.... it´s like
if a alien rock had injected it´s own DNA into that first moment when you were
going to appear....and instead of a child....your mummy has a...ROCK!!! or twin
ROCKS!!!! Watch this
video
*We are
learning to use this unique ability that viruses have for changing the DNA of a
cell in our benefit. In this video you can see how scientist got the terrible
HIV virus, modified it in a lab, and injected it in a very ill girl. Let´s see
if you understand what happened? Click
me
*
Fungi are
microbes that have been traditionally connected with the plant kingdom. Many
scientists will disagree with this idea. What they have in common is that they
will grow in humid (wet), dark, warm places, and they will grow on some
form of decay (some organic material that is rotting).
-Mushrooms:
We have all seen mushrooms grow in our forests in autumn.
-Moulds:
We might have also seen in a basement, in a garage, or in a house wall, a
stain that is caused by the humidity of the rainy days. Or maybe some
dark green thingy that has grown on a
piece of bread or an orange that we abandoned in a corner a long time
ago.
-Yeasts:
Maybe you like to help in the kitchen and you have cooked either bread, cakes,
cup-cakes... If you have, you have used these micro-organisms to make these
foods fluffy and spongy.
3.
LOUIS PASTEUR AND MICRO-ORGANISMS
In the
1800s a scientist called Louis pasteur had been working investigating diseases.
Using the microscope he was trying to prove the causes of illnesses.
One day
he was asked to investigate a mysterious case that affected silkworms. Silkworm
eggs had not been hatching properly, and many caterpillar died. The french silk
industry was losing a lot of money.
He used
his microscope to look for any clues in the eggs and caterpillars. He found rod-shaped
bacteria in both. So he tried this experiment to find out if these
microbes were really responsible for the illness:
-He fed
healthy caterpillars with mulberry leaves smeared with the infected remains of
diseased caterpillars.
-He fed
a second group with fresh mulberry leaves that had had no contact with ill
caterpillars.
-He
observed and compared results.
His
conclusion was:
·The
disease was caused by the rod shaped micro-organism he had seen with his
microscope.
·This
disease could pass from caterpillar to caterpillar not only by direct contact,
but also through the mulberry leaves!
·Infected
silkworms had to be separated from the rest. The food from the infected
caterpillars should not be re-used for the healthy ones. All the area that had
had contact with the infected silkworms had to be thoroughly cleaned
(desinfected).
Louis
Pasteur: mini-biography
4.
VACCINES AND VACCINATION
Lady
Mary Montagu photo
In 1717
an woman called Lady Mary Wortley Montagu and married to a British embassador
had to move to Turkey. She learned the language, observed all Turkish
customs and wrote much about everything that surprised during those two years.
One
thing that caught her attention was a practice that until then had never been
recorded in Europe. She observed how doctors in Turkey would get the pus from a
blister caused by smallpox (a deadly disease) and they would infect a healthy
person!!!!!!
Smallpox
was killing many people all around the world. Lady Mary´s own brother had died
of this infection. She decided to take the risk and tried it, even in her own
son.
When
she got back to England she told everybody about this new medical technique.
They called it INOCULATION. It seamed to work in a high % of the cases. King
George I followed the example an had his grandchildren inoculated.
It
worked, but it was not perfect. When Lady Mary Montague died in 1762, a boy
called Edward Jenner was 13 years old.
Edward
Jenner
Many
scientists had been working on the way to improve INOCULATION. For although it
was saving many lives it had also caused healthy people to become seriously
sick.
In 1796
Dr Edward Jenner was ready to try his latest experiment. He had observed that
people that had milked cows sometimes caught a disease called cowpox. This was
not new. What did surprise him was that these people never got
smallpox!!!! So the 14th of May he tried this experiment on his gardeners son,
an 8 year old boy called James Phipps
-
Jenner got pus from the hand of a milkmaid infected with cowpox.
- He
scratched some of the infected pus onto James´arm.
- He
observed how James became ill with cowpox but soon got better.
- Then
Dr. Jenner got pus infected with the deadly smallpox.
- He
infected James a second time, now with the deadly smallpox.
- He
observed how James developed a scab (costra) but HE WAS SAFE FROM SMALLPOX!!!!
- Dr
Jenner decided to infect local children with cowpox in order to protect them
from smallpox.
Louis
Pasteur.
Louis
Pasteur gave these theories another push when in the 1870s he discovered
another technique. His idea was simple:
-Get
the disease and learn how to make it weaker, make it lose its strength, make it
lose its power. Then inject it into the healthy body.
-This
would allow our antibodies (our internal army, responsible for the destruction
of all strange visitors) to "train" with them, learn how to attack
them, and find the way to destroy them when the "strong big brother"
entered the body in a future occasion.
This is
called VACCINATION
Here you
have some pictures of antibodies attacking an infection.
Here you have a
video of antibodies chasing and killing bacterias.
CONCLUSION:
So
nowadays when a child is born the hospital gives the parents a calendar of
vaccination. Parents are asked to go to the doctor to get a set of injections
(vaccines). The child receives these mild infections that will prepare him for
the really ugly attacks.
Here you
have your own vaccination calendar. Ask your parents to show you your
vaccination diary. They might not have it, because with the usage of computers,
we parents don´t have to worry about remembering them, the doctor will remind
us if it is time for the next.
5.
USING MICRO-ORGANISMS
Until
now everything said about microbes has been quite negative. We are left with
the impression that microbes have been created just to harm us. It is important
to understand that microbes have a very important position in the food chain,
and therefore in the cycle of life. And not only that, we also use
micro-organims for our own benefit.
·
YOGURT. To make yogurt we heat milk to about 90ºC for 5 to 10 minutes. This kills the harmful bacteria that
may be living on it.
The
milk then is cooled down to aproximately 40ºC. In this point is when we add the
"starter culture". The starter culture are harmless bacteria that
will feed on the natural sugar of the milk, transforming the liquid milk into
an acid flavoured yoghurty mass. This goes on for about 3 hours.
After
the 3 hours it is time to bring the temperature down to stop the action of the
bacterias. The flavours and the sugar are added to create the different tastes.
The
yogurt must now stay at about 4ºC all the way from the factory to your home
fridge.
BREAD.
Bread is a mixture of flour, oil, water, and salt. To all this we must add a
micro-organism called yeast. The yeast will feed on the natural sugars of the
flour, and in exchange produce micro-particles of gas that will make your bread
spongy and fluffy. Here,
watch. Here
But to
finish why not mention:
Kefir.
A kind of yogurt that we can trace back to the Caucasus mountains 3000BC, and
that keeps is supposed to keep your defenses strong. Something that we have
copied to create Actimel.
Bacteria
that live naturally in your intestines (dirtiest part of your body) and that
help clean it.
Microbes
that "eat" the plastic rubish floating in our oceans.Here
Microbes
that will get rid of the organic rubish that we produce.
Medicines:
Penicillin
And more
EXTRAS
