The scientists who came with a major contribution to the development of microbiology:
PROJECT PART I
 |
| Leeuwenhoek |
Antonie van Leeuwenhoek (1632-1723) was
born and lived in Delft, Netherlands. He was from a modest family of tradesmen.
He himself made his living as a draper and a minor city officer. Antonie did
not receive a high education degree, nor academic training. But his insatiable curiosity and his tenacious assiduity and rigor allowed him to make some among the most
important scientific findings in the field of biology: the discovery of
microorganisms.
After he read a copy of Hooke’s work Micrographia, Leeuwenhook started to make his own microscopes and he used
them to observe things. He is credited to have been the first to observe
bacteria. The tiny organisms he saw through his lenses he called “animalcules” (little animals). His microscopes were magnifying glass mounted on a small brass structure. These were rudimentary microscopes but they
were magnifying enough to allow him to observe the blood cells and sperm cell
among many other living thing like Spirogyra and Vorticella.
Leeweenhoek sent his discoveries with drawings what he saw and his comments to the Royal Society of London, an institution
of which he became a fellow. A specimen of Leeuween’s microscope is
conserved at the Delft University of Technology, Netherlands.
 |
| Leeuwenhoek's microscope, Deft. |
 |
| Tyndall |
John Tyndall (1820-1893) was an Irish scientist. His work has been fundamental to the development of microbiology, especially the research surrounding the “germ theory”. In 1877, Tyndall demonstrated that dust did carry germs and that if dust was absent, broth remained sterile even if directly exposed to air. Providing a blow to spontaneous generation. He also created a process to destroy heat-resistant bacteria by eradicating bacteria spores. He used a set up to preserve broth in “optically pure” air, which means he isolated the broth from direct exposure to air a way to avoid any contamination by the germs from the dust in the air, and the result was that the meat he kept in “optically pure” air did not decompose. During the 1870s Tyndall was in frequent communication with Pasteur. This technique explained above is still know as Tyndalization.
 |
| Cohn |
Ferdinand
Cohn (1828-1898), was a German biologist. His studies concerned
the bacteria, and fungi and the
algae. Cohn described the physiological processes in microorganisms. In 1849 at
the university of
Breslau
 |
| Needham |
John Turberville Needham (1713–1781) was an English biologist. He studied in London
and Paris.
 |
| Lister |
Joseph Lister (1827-1912) British Surgeon. He was professor of Surgery at Glasgow University
 |
| Linnaeus |
Carolus Linnaeus (Swedish Carl von Linné) was a Swedish scientist. He was born on 23 May 1707 and died 10 January 1778 at the age of 91. Linnaeus lays the basic formation of the formal system of classification system of the binomial nomenclature. This classification system grouped organism based on ancestral relationships.
The value of the binomial nomenclature system derives primarily from its economy, its widespread use, and the uniqueness and stability of names it generally favors. It generally speaking allows us to see the order of life. Linnaeus is the inventor of the modern taxonomy.
 |
| Appert |
Nicolas Appert was born 17 November 1749 and died on 1 June 1841
at the age 91. Appert was the French inventor of airtight food preservation. In
1810, after 15 years of experimenting with how to preserve new food he
published The Art of Preserving Animal and Vegetable Substances. By
boiling the food you kill the bacteria and seal it. Preserving it allows people
to better store there food and for a much longer period of time.
 |
| Schleiden |
Matthias Jakob Schleiden was born 5 April 1804 and died 23 June 1881 at the age of
77. He wrote Contributions to Phytogenesis in 1838, in which he stated that the
different parts of the plant organism are composed of cells. Because of this
Schleiden and his partner Schwann became the first to formulate what was then
an informal belief as a principle of biology equal in importance to the atomic
theory of chemistry.
 |
| Koch |
Robert Koch was born 11 December 1843 and died on 7 May 1910 at the age of 67. He is called the founder of modern bacteriology. He is known for his role in identifying the specific causative agents of tuberculosis cholera and anthrax. He his research also led to the creation of Koch’s postulates. Due to the scientist where able to give the scientific support for the concept of infectious disease and link specific organisms to certain diseases. He put forward the "Koch Postulates" a unanimously accepted process to determine the relationship between germs and diseases.
Koch's Postulates
Four
criteria that were established by Robert Koch to identify the causative agent
of a particular disease, these include:
1.
the
microorganism or other pathogen must be present in all cases of the disease
2.
the
pathogen can be isolated from the diseased host and grown in a pure culture
3.
the
pathogen from the pure culture must cause the disease when inoculated into a healthy,
susceptible organism
4.
the
pathogen must be re-isolated from the new host and shown to be the same as the
originally inoculated pathogen.
 |
| Koch's Postulates diagram |
 |
| Haeckel |
Ernst Haeckel was a German zoologist (1834-1919). He was very
well known in the field of science due to him combining two theories cell
theory with evolution theory. As well as his explanation of the initial state
of multi-cellular organisms from colonies of single-cell protists that play a
very significant role in biology. One of Haeckel’s main points, is to prove
that organism can be systemically arranged according to a classification system
from the most complicated to the most basic levels of individuality. They can
be organized any which way. From single-cell organisms to higher animals and
animal societies while evolution can explain the existence of these organisms.
 |
| Spallanzani |
Lazzaro Spallanzani was an Italian Physiologist (1729-1799). Spallanzani contributed a very important finding to biology. He proved that “Spontaneous Generation” did not exist. He also confirmed that John Needham’s experiment was flawed. Needham boiled broth and heated the flask, but did not take into consideration that air was a factor in his experiment. The air caused bacteria to grow in the broth, hence he thought that spontaneous generation existed. On the other hand, Spallanzani took two flask one sealed airtight, while the other was sealed after it was exposed to air. The conclusion was that the one with air got the same results as Needham. The one that was sealed initially was not growing any life in it. Even though it was proven that spontaneous generation does not exist, many still doubt Spallanzani’s findings.
 |
| Redi |
Francesco Redi , an Italian physician and poet, was born on February 18, 1626 in Arezzo, Italy and died March 1, 1697, Pisa. He demonstrated that the presence of maggots in decomposed meat does not result from spontaneous generation but from eggs placed on the meat by flies.
 |
| Redi's experiment |
In 1668 he shared a series of experiments named as
Esperienze Intorno alla Generazione degl'Insetti (Experiments on the Generation
of Insects) which was one of the first theories refuting "spontaneous
generation", Redi set up a series of jars containing different meats, some
of the jars were covered and some of the jars were exposed to open air. Then he
repeated the experiment but, instead of sealing the containers, he covered half
of them with gauze so that air could go inside the jars. Even
though the meat in all of the jars putrefied, he found that only in the open
and uncovered ones, in which flies had entered freely, the meat had maggots.
Leading to the conclusion that the maggots came from the eggs left on the meat
by the flies; however, Redi still believed that the process of spontaneous generation
was possible in cases such as: gall flies and intestinal worms.
 |
| Schwann |
The
German biologist Theodor
Schwann (1810-1882) is best
known as the founder of the cell theory. He also was responsible for the
discovery of pepsin which the first digestive enzyme prepared from animal
tissue, and last but not least, he discredited the theory of spontaneous
generation. In 1834 he decided to take boiled broth to heated air in a
glass tube, resulting in the fact that no micro-organisms were detectable and
no chemical change or decomposition occurred in the broth. He was convinced
that the idea of spontaneous generation was false. In 1838 after studying
Matthias Schleiden's microscopic research on plants who basically proposed
a plant cells’ theory which was the key to plant anatomy and growth;
Schwann decided to focus his research on animal tissues, theory that
actually proved the existence of cells and the development of mature tissue
from its very first stage as an embryo; furthermore, animals and plants are
made of cells and the fluids that come out of them, cells have its own life and
finally, without cells there is no organism. Every cell can be placed into
groups: Those that together are formed by molecules and those by chemical
changes, this gave birth to classification of tissues into five big groups, the
ones formed by individual cells like blood and skin; formed by blended cells as
cartilage and bones, large cells that formed fibers like tendons and ligaments
and the those that form muscles from fused cells.
 |
| Hooke |
Robert Hooke was an English philosopher, mathematician and scientist of the 17th Century who was born on July 18, 1635. Although he was mainly educated at home by his father, he managed to enter Westminister School at age thirteen and went on to Oxford University, where some of the best scientist in England worked at the time. Robert Hooke is remembered in the history of microbiology for his 1665 publication of the book “Micrographia”.
 |
| Hooke's microscope |
In this book he inspired use and introduced the microscopes for the first time for scientific exploration, thrugh his amazing drawings, he was able to illustrate what he had discovered, in a thin piece of cork, he saw honeycomb-like structures which later he called a Cell. He was the first person to use the term “Cell” to describe a basic unit of life.Hooke was an early advocate of biological evolution. Hooke is also credited with the invention of microscope.
 |
| Metchnikoff |
Elie
Metchnikoff, whose original name was llya llich
Mechnikoff was a Russian scientist born on May 16, 1845. He was a brilliant man
who studied Zoology and Microbiology . In 1883, he presented “The
Curative Forces of the Organism,"
Metchnikoff's theory of phagocytes. Phagocytes (eating/Cells), such as
leukocytes or white blood cells work as our front line defense against
infections. According to Metchnikoff, under appropriate conditions,
protector cells within an organism would engulf, mount, attack and ingest
foreign bodies, such as bacteria to protect us from invading matters. . This
phenomenon known as Phagocytes would become a fundamental part of our immune
response system. This discovery honored Mechnikovff to receive the Nobel Prize in 1908. Elie
Metchnikoff made significant contributions to biology, life science and medicine.
 |
| von Dusch |
Theodor
von Dusch was born
on Spetember 17, 1824 and was a German
physician. In 1850’s He, along with Heinrich Schroder revealed that a filter
made of cotton-wool was effective in removing microbes, such as bacteria from
the air. In 1854, Georg Schroeder and von Dusch performed a
convincing experiment to disprove the theory of spontaneous generation. Schroeder and von Dusch were the first to present the idea
of using cotton plugs for plugging microbial culture tubes. Dusch was the
author of influential works such as thrombosis of cerebral sinuses, heart
disease and diseases of endocardium and myocardium. Georg Schoeder worked with von Dusch and both introduced a technique that consists of filtering the air trapping the microbes.
 |
| Pasteur |
Louis Pasteur was
born on December 27, 1822 in Dole France. He was a doctor, chemist and inventor
who is known for the “germ theory of disease”. Perhaps since three of his
children died of typhoid fever, that could have been the drive to save people
from dying. Pasteur discovered that most infections are caused by germs and
bacteria, he figured that if germs was the cause of fermentation, then germs
had to be cause of contagious diseases. He fought with hospitals to change
their practice and pasteurize all medical equipment to minimize the spread of
germs.
Pasteur’s pasteurization process killed germs and prevented the
spread of diseases. In 1879, Pasteur’s created the first vaccine for Chicken
Cholera, he demonstrated that they become resistant to the actual virus, and
soon after, he developed vaccination for diseases such as anthrax, Cholera, TB
and smallpox and rabies. He is the reason antibiotics and vaccines exist today.
 |
| Pasteur's swan neck flask experiment |
 |
| Gram |
Hans Christian Joachim Gram was a Danish bacteriologist that is remembered for his development
of the “Gram Stain”. In 1884, Gram accidentally came across a method on how to
distinguish between two major classes of bacteria to make them more visible
under the microscope. The gram stain consists of a primary stain of Crystal
Violet and a counterstain of Safranin, bacteria that turn purple are called “Gram
positive” and these that turn red are “Gram Negative.
Identifying and
characterizing bacteria is widely used in microbiology, it reflects essential
differences in biochemical and structural properties of bacteria.
 |
| Gram's Staining |
PROJECT PART II
Major microbiologists' position regarding the opposing theories: spontaneous generation and biogenesis.
#
|
NAME OF SCIENTIST
|
THEORY
|
TITLE OF EXPERIMENT
|
|
SPONTANEOUS GENERATION
|
BIOGENESIS
|
|||
1
|
Leeuwenhoek
|
N/A
|
N/A
|
Microscope
|
2
|
Tyndall
|
x
|
Tyndallization
| |
3
|
Cohn
|
N/A
|
N/A
|
Germ
Theory
|
4
|
Needham
|
x
|
Germ
Theory
| |
5
|
Lister
|
N/A
|
N/A
|
Germ
Theory
|
6
|
Joblot
|
x
|
Germ
Theory
| |
7
|
Linnaeus
|
N/A
| ||
8
|
Appert
|
x
|
Germ
Theory
| |
9
|
Schleiden
|
Cell
Theory
| ||
10
|
Koch
|
Germ
Theory of Disease
| ||
11
|
Haeckel
|
x
|
Cell
Theory
| |
12
|
Redi
|
x
|
Germ
Theory
| |
13
|
Schroeder
|
Germ
Theory
| ||
14
|
Schwann
|
x
|
Cell
Theory
| |
15
|
Spallanzani
|
x
|
Germ
Theory
| |
16
|
Hooke
|
Microscope
| ||
17
|
Metchnikoff
|
x
|
Immunology
| |
18
|
Von
Dusch
|
x
|
Filtration
of microbes
| |
19
|
Pasteur
|
x
|
Germ Theory of Disease
| |
20
|
Gram
|
N/A
|
N/A
|
Gram
Stain
|
What
is the theory of ‘SPONTANEOUS GENERATION’?
According
to the Biology Online Dictionary and other online sources, the term spontaneous
generation was a popular hypothesis that stated that previous organisms develop
from nonliving matter. The theory dates back to Aristotle and ancient Greek
philosophy and continued to have support in Western scholarship until the 19th
century. Abiogenesis, which is the term used nowadays, basically held that
certain complex, living organisms were generated by decaying organic
substances. It was believed back in the days that aphids arose from the dew
which fell on plants. Also that flies developed from putrid matter as mice did
from dirty hay and crocodiles from rotting logs at the bottom of bodies of
water, and so on.
Many
microbiologist of the era such a Hooke and Van Leeuwenhoek felt that the
existence of microorganisms was evidence necessary to support spontaneous
generation, since microorganisms seemed too simplistic for sexual reproduction,
and asexual reproduction through cell division had not yet been observed. It
wasn't until 1668, when Francesco Redi showed with a simple experiment (the
sealed and unsealed flask) that no maggots appeared in meat when flies were
prevented from laying eggs. Thus, a new era was created, the era of biogenesis;
where many other experiments were carried out by other microbiologists of major
importance who proved the presence of microorganisms in the air, and added
other important milestones to the history of science: the introduction of
aseptic techniques to the medical field and the discovery of causative agents
of infectious diseases and their treatment.
BIOGENESIS
Biogenesis
is the principle or theory that living organisms develop only from other living
organisms, and not from nonliving matter as defined by the online dictionary
organization. The theory was attributed to Louis Pasteur, who demonstrated that
fermentation is caused by the growth of micro-organisms, and the emergent
growth of bacteria in nutrient broths is due not to spontaneous generation, but
rather to biogenesis. This is summarized in the phrase Omne vivum ex vivo,
Latin for "all life [is] from life." A related statement is Omnis
cellula e cellula, "all cells [are] from cells;" this observation is
one of the central statements of cell theory.
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