Wednesday, 9 January 2013
Tuesday, 25 December 2012
Louis Pasteur
Chemist and Biologist
December 27, 1822 -
September 28, 1895
Louis
Pasteur (pahs TOOR) was born to a tanner, Jean Joseph Pasteur and his wife
Jeanne in France in the ancient town of Dole. His father had been a soldier in
Napoleon's army.
They sent
Louis to a school in Arbois (Ahr-bwah) when he was six. He enjoyed drawing
portraits of his family and friends. At that time his skill seemed to be in the
field of art without a hint of his future fame as a scientist.
After he
graduated he went to the Royal College in Besancon (bih zan SAH(N) where he
earned his B.A. and then a Bachelor of Science degree two years later at the
age of twenty. In 1847 he received a doctorate degree and became a professor at
age twenty-six.
He fell in
love with and married Marie Laurent and they had five children, but only two of
them survived.
He named the
new science bacteriology* and suggested a new theory, The Germ Theory of
Disease. He believed that diseases were caused by germs attacking the body from
the outside.
The raising
of silkworms was a large industry in France at that time. People raised them in
their homes or in large sheds. The silk worms constantly ate mulberry leaves,
so the owners would even get up in the night to feed them. The silkworm would
spin a cocoon and become a chrysalis.
Then the cocoons were put in a steam stove, dried in the sun
and handed over to the weavers to unravel the silk threads. Each cocoon would
be composed of a single silk thread 1000-3000 feet long. A few of the cocoons
would be saved to develop into the moths which lay the eggs which hatched into
silkworms and start the cycle all over again.
In 1849 the worms were hit with a disease and began to die.
It first started in France and spread worldwide to every country except Japan.
In 1865 at the request of the government Pasteur performed experiments to find
the cause of the malady. Using the microscope he determined that corpuscles in
the infected worms were causing them to die. The worms would infect each other.
He helped the growers to find a way to isolate and then use eggs that were not
infected.
At the end of this arduous* task he suffered a stroke and
paralysis. For several months he was completely paralyzed. He was only 45 years
old. After two years he began to recover the use of his body.
His next task was to try and find the cause of disease in the
body. He developed a vaccine for a disease in chickens, fowl cholera, and a
disease in animals, splenic fever. After proving its success he began to
prepare a vaccine for large numbers of animals and by 1883 the number of
animals vaccinated against the disease called anthrax* reached nearly 500,000.
Pasteur
devoted the rest of his life developing vaccines for people against such
diseases as cholera, diphtheria, tuberculosis and smallpox.
The idea of
immunization* with a weakened version of a disease was not new. As early as
1774 a vaccine for smallpox* had been discovered, and Edward Jenner before 1800
was vaccinating people against smallpox. He found that if he inoculated people
with cowpox, they got the less severe disease which prevented them from getting
smallpox.
He is
especially remembered for the case in which he vaccinated* a nine-year-old boy,
Joseph Meister, who had been bitten by a dog that had rabies.* The boy
recovered after receiving the vaccine from Pasteur. When he grew up he became a
caretaker at the Pasteur Institute.
Thousands of
people since that time have received rabies vaccinations and been saved from
getting the disease which is almost always fatal.
The Pasteur
Institute was founded in 1888 in Paris. When he died he was buried there in a
fine tomb.
what did pasteur do
SO
WHAT DID PASTEUR ACTUALLY DO?
Pasteur
founded the science of microbiology and proved that most infectious diseases
are caused by micro-organisms. This became known as the "germ theory"
of disease. He was the inventor of the process of pasteurisation and also
developed vaccines for several diseases including rabies. The discovery of the
vaccine for rabies led to the founding of the Pasteur Institute in Paris in
1888.
SO
HOW DID PASTEUR MAKE HIS DISCOVERIES?
When he was
only twenty-six years old Pasteur solved a problem that had been puzzling the
great chemists of the day. He found that when light was passed through tartaric
acid - this was found in wine dregs, it produced a strange effect. Pasteur
proved that this was because the acid is actually not one acid but a mixture of
different acids. This find impressed the scientists of influence and
established Pasteur's reputation.
While at the
University of Strasbourg he became interested in fermentation and this interest
continued when he moved to the University of Lille. The faculty had been
established partly to serve as a means of applying science to the problems of
the industries of the region, especially the production of alcoholic drinks.
This work in fermentation enabled Pasteur to identify that the changes brought
about when beer or wine ferments, milk turns sour or meat decays, occur when
special micro-organisms are present.
As a result
of these findings Pasteur was asked to help the local breweries where the beer
had turned bad. The souring of wine and beer was a major economic problem in
France. Pasteur looked at some droplets of bad beer through a microscope and
observed that the beer contained small rod shaped bacteria, instead of round
yeast cells. Although micro-organisms are essential in fermentation they must
be the right ones. This was a major discovery. Pasteur made brewing a more
scientific procedure and showed brewers how to culture the right organisms for
good beer. He also demonstrated to the wine industry that if wine is gently
heated to sixty degrees celsius for a short time, the growth of harmful
bacteria is prevented and the wine does not go sour in bottles or barrels.
Pasteur then
extended this to other problems such as the souring of milk. He proposed
heating the milk to a high temperature and pressure before bottling. The
process is now in widespread use and is called pasteurisation.
WHAT
OTHER DISCOVERIES DID PASTEUR MAKE?
By 1857
Pasteur had become world famous and took up an appointment as director of
scientific studies at the Ecole Normale in Paris. He was asked to help to
investigate a serious disease that was ruining the silk industry in southern
France. The disease known as pebrine attacked the silk worms. The signs of the
disease were that the eggs did not hatch or the worms would die before making
their silk cocoons. It had now reached epidemic proportions and even disease
free worms brought in from Spain and Italy had been contaminated. By 1864 there
were no uncontaminated eggs left, except for those brought in from Japan.
Pasteur
observed through his microscope that the diseased caterpillars and eggs all
contained tiny organisms. He identified these as disease producing organisms.
He managed to obtain some healthy worms and he divided them into two lots. He
fed one lot with mulberry leaves smeared with the remains of diseased worms and
fed the others with mulberry leaves smeared with the remains of healthy worms.
Pasteur was able to show that the worms fed on diseased smeared leaves got the
disease, whereas those fed on uncontaminated leaves remained disease free. He
then worked with the silk industry to devise a simple way of keeping silk worms
under healthy conditions and therefore disease free.
Not only had
Pasteur rescued the French silk industry but he had established the connection
between bacteria and disease. The connection had not been fully understood
before.
This was a major discovery.
Pasteur's work on the link between bacteria and disease came
to the attention of the famous Edinburgh surgeon Lord Lister. Lord Lister was
concerned with the number of people who died after having operations in
hospital. To combat infection, Lister introduced disinfectant sprays during
operations, these prevented bacteria from entering a wound. He also introduced
the use of dressings soaked in carbolic acid and strict hygiene rules to combat
sepsis. The sterile methods introduced by Lister, drastically reduced the
number of hospital deaths.
In France at that time many cattle suffered from anthrax, a
serious disease from which many of them died. Pasteur made a careful study of
anthrax and noticed that some cows developed the disease more severely than
others. So he decided to inject two cows with a strong dose of the anthrax
bacteria, fully expecting them to die. To Pasteur's amazement neither of them
developed the disease. Later, he found that both animals had already suffered
from anthrax. Could they be immune to it? Could they be protected in some other
way? Pasteur believed that if it were possible to give an animal a mild attack,
this might be sufficient to prevent it from getting the disease later on.
Eventually, after many experiments Pasteur succeeded in
producing a weakened and harmless culture of anthrax bacteria. He inoculated
cattle and sheep with this giving them a mild form from which they recovered.
When these animals were put with others who had a severe form they remained
unaffected. They were immune.
Pasteur worked throughout the rest of his life on the
various causes of diseases and how these could be prevented by vaccination.
PASTEUR AND RABIES
Pasteur is particularly renowned for his work on the vaccine
for rabies, a highly contagious infection which attacks the central nervous
system. It enters the body through the bite of an infected animal or through
infected saliva entering an existing wound. After experimenting with the saliva
of animals suffering from the disease, Pasteur concluded that the disease rests
in the central nervous system of the body. When an extract from the spinal
column of an rabid dog was injected into healthy animals symptoms of rabies
were produced. By studying the tissues of infected animals- rabbits, Pasteur
was able to produce an attenuated form of the virus. This could be used for
inoculation.
On July 6 1885, Pasteur tested his pioneering rabies vaccine
on man for the first time. He saved the life of a young man called Joseph
Meister who had been bitten by a rabid dog. Pasteur was urged to treat him with
his new method. The treatment lasted 10 days and at the end he recovered and
remained healthy. Since then thousands have been saved by this treatment.
On March 1886, Pasteur was invited to present his results to
the Academy of Sciences and in 1888 went on to found the Pasteur Institute in
Paris. This was a pioneering clinic for the study of infectious diseases, the
treatment of rabies and a centre for teaching. Pasteur directed the Institute
personally until he died. The Pasteur Institute is still one of the most
important centres in the world.
Pasteur became a national hero and was honoured in many
ways. He died at Saint-Cloud on 28 September 1895 and was given a state funeral
at the Cathedral of Notre Dame and his body placed in a permanent crypt at the
Pasteur Institute.
Modifications of the Pasteur method are still used in rabies
therapy today. The traditional vaccine contains inactivated rabies virus grown
in duck eggs. A newer vaccine which contains virus prepared from human cells
grown in the laboratory is safer and requires a shorter course of injections.
biografhy
BiOgRaFhY
French chemist and
bacteriologist. Conducted several investigations in the field of natural
sciences, and is considered the founder of stereochemistry and the driver of
microbiology and immunology. But what is most known for having developed the
rabies vaccine, which was a total success.
Their findings were of great
importance in various fields of natural sciences. The significance of their
work has made it regarded as the founder of stereochemistry and the driver of
microbiology and immunology.
He was born on December 27, 1822
in Dole, France. His father, who had been a soldier of Napoleon, had a tannery
where he worked to support his family. Louis spent his childhood in the city of
Abois, where his parents settled in 1827.
He studied at the Liceo de
Besançon and the Ecole Normale Supérieure in Paris, where he received his
doctorate in physics and chemistry in 1847. He was then professor of chemistry
at the University of Strasbourg (1847-1853), and dean of the University of
Lille in 1854.
In 1857 he was director of
scientific studies of the Ecole Normale de Paris, whose lab conducted in 1867.
He was also director of the Institute that bears his name since its creation in
1888 until he died (1895).
Pasteur's contributions to
science were numerous and began his research in organic chemistry. Optical
isomerism discovered (1848) by crystallization of racemic acid, which obtained
crystals of two different ways. It is considered that this work gave rise to
the stereochemistry. Moreover, this finding the young chemist, who was 26
years, received the French Legion of Honor.
Used a new method to kill
microorganisms that could degrade the wine, beer or milk. This procedure is
called pasteurization and has universal application in the food industry, which
was developed to prevent the alteration of food.
The similarity between the
processes of fermentation and putrefaction and suppuration of wounds, enabled
the implementation of its findings to the surgery. In 1871, Pasteur forced the
military hospital doctors to boil the instruments and bandages. Described an
oven, called Pasteur oven, useful for sterilizing surgical instruments and
laboratory equipment.
In 1865 a scientist discovered
the mechanisms of transmission of the pebrine, a disease of silkworms, who then
threatened to sink the French industry. As a result of his work called
enunciated the germ theory of disease, which states that they start with the
penetration of pathogenic microorganisms in the human body.
After 1870 Louis Pasteur
investigated on communicable diseases, and in 1881 he studied about the anthrax
in sheep, and succeeded in preparing a vaccine of bacteria off, the first in
history.
His work as a researcher was
indefatigable. Thus he developed the vaccine against rabies, or hydrophobia,
the last great contribution he made to science. The effectiveness of it was
successfully tested on July 6, 1885, in a child who had been bitten by a rabid
dog and, thanks to the vaccine did not develop rabies.
Popular support made possible
the construction of the Pasteur Institute, which had since its beginnings a
deserved international reputation. In 1882 Pasteur was elected to the French
Academy. He died on September 28, 1895 in Villeneuve.
Wednesday, 19 December 2012
WHO WAS LOUIS PASTEUR?
LOUIS PASTEUR (1822-95)
Louis Pasteur was a world renowned French chemist and biologist. He was born on December 27 1822 in the town of Dole in Eastern France. Pasteur's parents were peasants, his father was a tanner by trade. He spent the early days of his life in the small town of Arbois where he attended school and where it seems that Pasteur did not do very well, preferring instead to go fishing. His headmaster, however, spotted potential in Pasteur and encouraged him to go to Paris to study. So, aged fifteen Pasteur set off for Paris hoping to study for his entrance exams. Unfortunately, the young Pasteur was so homesick that his father had to travel to Paris to bring him home. He then continued to study locally at Besancon, until he decided to try again in Paris. This time he succeeded and went on to study at the Ecole Normale Superieure. Curiously, although the young Pasteur worked hard during his student days he was not considered to be exceptional in any way at chemistry.
In 1847
Pasteur was awarded his doctorate and then took up a post as assistant to one
of his teachers. He spent several years teaching and carrying out research at
Dijon and Strasbourg and in 1854 moved to the University of Lille where he
became professor of chemistry. Here he continued the work on fermentation he
had already started at Strasbourg. By 1857 Pasteur had become world famous and
took up a post at the Ecole Normale Superieure in Paris. In 1863 he became dean
of the new science faculty at Lille University. While there, he started evening
classes for workers. In 1867 a laboratory was established for his discovery of
the rabies vaccine, using public funds. It became known as the Pasteur
Institute and was headed by Pasteur until his death in 1895.
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