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The following points highlight the top eight Eminent Microbiologists of all Times. The Eminent Microbiologists are: 1. Antony Van Leeuwenhoek (1632-1723) 2. Edward Jenner (1749. 1823) 3. Louis Pasteur (1822-1895) 4. Robert Koch (1843- 1910) 5. M.W. Beijerinck (1851-1931) 6. Dimitri Iwanowsky (1864-1920) 7. Sergei Nikolaievich Winogradsky (1856-1953) 8. Alexander Fleming (1881-1955).
Eminent Microbiologist # 1. Antony Van Leeuwenhoek (1632-1723):
In 1632, Antony Van Leeuwenhoek was born on October 24, in Delft, Holland. He had a hobby of grinding lenses to see small things bigger.
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He saw many things with them: insects, fabric, dust, etc.
In 1675, while observing rainwater drops, he saw some minute creatures in them. His microscope could magnify thing to about 200 times. To these minute things he observed he called them animalcules. In 1677, he also for the first time observed insect spermatozoa, red blood cells and flow of blood in capillaries (small blood vessels).
During his lifetime Van Leeuwenhoek ground over 500 optical lenses. He also created over 400 different types of microscopes, and only nine of which exist today. His microscopes were made up of silver or copper metal frames holding hand-ground lenses.
Those that have survived the years are able to magnify up to 275 times. Thus driven by insatiable curiosity and infinite energy, he devoted some 50 years of his life to his passion-microscopy. But he was not pursuing his hobby of microscopy, until he was 40.
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He had recorded all his findings to the Royal Society of London. And all these letters were published in the “Philosophical Transactions of the Royal Society”.
Leeuwenhoek’s subjects for microscopy were extremely diverse and included objects from the human, animal, plant and mineral kingdoms. He examined tartar of teeth, saliva, gum scrapings, hair, nails, bones, teeth, various soft tissues, and the lens of the eye, as well as various biological fluids, including blood, milk, sweat and tears.
Other subjects of his studies included feathers, animal fur, insect parts, minerals, fish scales, spices, nuts, seeds, tree bark and cork.
Leeuwenhoek provided accurate descriptions of plant anatomy. Even gunpowder, before and after being ignited, came under his microscopic scrutiny. He used saffron as a means to render tissues such as muscle more easily visible, and he also described blood corpuscles and capillaries.
An expert lens maker, Leeuwenhoek ground and polished his own lenses. He used a simple microscope, although compound microscopes were available at the time. He prepared sections with the aid of a razor and cut them with his own hand. For sketches and illustrations accompanying his written observations, he sought the services of a draftsman.
Leeuwenhoek did not write in English or Latin and spoke only Dutch. It was Reijnier de Graaf who wrote to the Royal Society in 1673 informing them of Leeuwenhoek, describing him as the resident genius of Delft who devised remarkable microscopes. Graff’s efforts introduced Leeuwenhoek to the most important learned society of the time.
Accompanying Graff’s introductory note was the first letter to the Royal society written by Leeuwenhoek, which deals with observation on the structure of mold, bee and the louse. This note launched Leeuwenhoek’s entry into the nascent world of microscopy.
Leeuwenhoek gave detailed descriptions of protozoa and bacteria. He noted that “little animals” lived in all kinds of water-lakes, wells, canals, and even rain.
His first observations on free living protozoa probably began with his discovery of little animals, or “animalcules,” in fresh water from a lake, which he recorded in a 1674 letter to the secretary of the Royal Society, Henry Oldenburg. Leeuwenhoek’s celebrated letter of October 9, 1676, contained the first account ever written of bacteria and outlined his pepper water experiment.
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In April 1676, in what might have been an attempt to discover “the cause of the hotness or power whereby pepper affects the tongue,” Leeuwenhoek placed some pepper in water. Three weeks later, on April 24, 1676, he discovered an incredible number of very little animalcules marking the first sighting of bacteria. Robert Hooke repeated the pepper water experiment and confirmed Leeuwenhoek’s observations.
The Fellows of the Royal Society also got a glimpse of “great numbers of exceedingly small animals swimming to and fro”. In 1683 Leeuwenhoek presented another famous communication on bacteria found in saliva and tooth scrapings from his mouth.
It is one of the miracles of science that two men from the town of Delft made pioneering contributions to the problem of generation and reproduction. Reijnier de Graaf, also of Delft, discovered the ovarian follicles named after him. Leeuwenhoek made groundbreaking observation in andrology by describing spermatozoa.
A medical student, Johan Ham. was the first to see animalcules (spermatozoa) in human semen, and drew this to Leeuwenhoek’s attention.
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Leeuwenhoek credited Ham with the discovery in his letter of November 1677. Leeuwenhoek went on to document the presence of animalcules in other species. He was one of the strongest opponents of the doctrine of spontaneous generation in the 17th century (Abiogenesis opponent).
This pioneer microscopist revealed little information on how he perfected his lenses and his “particular manner of observing very small creatures”. The magnifications achieved with his lenses ranged between x 30 and x 200, with one lens estimated to have a magnification of x 270 and a resolving power of 1.4 µm.
It is believed that Leeuwenhoek might have attained even higher magnifications. He used a special technique for viewing and lighting his objects, which he never divulged.
It has been suggested that Leeuwenhoek might have used some simple means of dark-field illumination to visualize details such as flagella on bacteria. Before the invention of the micrometer, it was difficult to measure the size of small objects under the microscope. Leeuwenhoek tried ingenious ways to estimate the size of his animalcules.
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Some themes he used for size comparison included grains of sand, a human red blood corpuscle, the millet seed, and “a hair’s breadth”.
Leeuwenhoek neither lectured nor wrote formal scientific papers but rather presented his observations in his letters. Nevertheless, he was recognized as an original scientist and was admitted as a fellow to the Royal Society. Leeuwenhoek was visited by many celebrities of his time, including royalty.
The leading microscopist of Delft died on August 26, 1723, at the age of 90. His contributions to science have been well documented by several authors, most notably by the late Clifford Dobell in his captivating book, Antony van Leeuwenhoek and His Little Animals.
In addition to the 26 microscopes and preparations he bequeathed to the Royal Society, Leeuwenhoek left behind a large collection of microscopes and mounted lenses, which were auctioned 2 years after his daughter Maria died. Leeuwenhoek was one of the most curious and original men who ever lived. He saw what had never been seen before.
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The medical world continues to be in awe of this extraordinary genius who unveiled the mysteries of Nature under the microscope.
Eminent Microbiologist # 2. Edward Jenner (1749. 1823):
Edward Jenner was born on May 17, 1749, in Berkeley, Gloucestershire.Edward was orphaned at age of 5 and went to live with his elder brother.
During his early school years, Edward developed a strong interest in science and nature that continued throughout his life. At the age of 13 he was apprenticed to a country surgeon and apothecary in Sodbury, near Bristol.
In 1764, Jenner began his apprenticeship with George Harwicke. During these years, he acquired a sound knowledge of surgical and medical practice. Upon completion of this apprenticeship at the age of 21, Jenner went to London and became a student of John Hunter, who was on the staff of St. George’s Hospital in London.
Hunter was not only one of the most famous surgeons in England but he was also a well-respected biologist, anatomist, and experimental scientist.
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The firm friendship that grew between Hunter and Jenner lasted until Hunter’s death in 1793. Although Jenner already had a great interest in natural science, the experience during the 2 years with Hunter only increased his activities and curiosity.
Jenner was so interested in natural science that he helped classify many species that Captain Cook brought back from his first voyage. In 1772, however, Jenner declined Cook’s invitation to take part in the second voyage.
Jenner occupied himself with many matters. He studied geology and carried out experiments on human blood. In 1784, after public demonstrations of hot air and hydrogen balloons by Joseph M. Montgolfier in France during the preceding year, Jenner built and twice launched his own hydrogen balloon.
Jenner was elected a fellow of the Royal Society in 1788. His last work, published posthumously, was on the migration of birds.
In addition to his training and experience in biology, Jenner made great progress in clinical surgery while studying with John Hunter in London. Jenner devised an improved method for preparing a medicine known as tartar emetic (potassium antimony tartrate). In 1773, at the end of 2 years with John Hunter, Jenner returned to Berkeley to practice medicine.
There he enjoyed substantial success, for he was capable, skillful, and popular. In addition to the practice of medicine, he joined two local medical groups for the promotion of medial knowledge and continued to write occasional medical papers. He also played violin in a musical club and wrote light verse and poetry.
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As a natural scientist, he continued to make many observations on birds and the hibernation of hedgehogs and collected many specimens for John Hunter in London.
While Jenner’s interest in the protective effects of cowpox began during his apprenticeship with George Harwicke, it was in 1796 when he made the first step in the long process whereby smallpox, the scourge of mankind, would to be totally eradicated.
For many years, he had heard the tales that dairymaids were protected from smallpox naturally after having suffered from cowpox. Pondering this, Jenner concluded that cowpox not only protected against smallpox but also could be transmitted from one person to another as a deliberate mechanism of protection.
In May 1796, Edward Jenner found a young dairymaid, Sarah Nelms, who had fresh cowpox lesions on her hands and arms.
On May 14, 1796, using matter from Nelms’ lesions, he inoculated an 8-year-old boy, James Phipps. Subsequently, the boy developed mild fever and discomfort in the axillae. Nine days after the procedure he felt cold and had lost his appetite, but on the next day he was much better.
In July 1796, Jenner inoculated the boy again, this time with matter from a fresh smallpox lesion. No disease developed, and Jenner concluded the protection was complete.
In 1797, Jenner sent a short communication to the Royal Society describing his experiment and observations. However, the paper was rejected. Then in 1798, having added a few more cases to his initial experiment, Jenner privately published a small booklet entitled.
An Inquiry into the Causes and Effects of the Variolae Vaccinae, a disease discovered in some of the western counties of England, particularly Gloucestershire and Known by the Name of Cow Pox. The Latin word for cow is vacca, and cowpox is vaccinia-, Jenner decided to call this new procedure vaccination.
Jenner went to London in search of volunteers for vaccination. However, after 3 months he had found none. In London, vaccination became popular through the activities of others, particularly the surgeon Henry Cline, to whom Jenner had given some of the inoculant.
Later in 1799, Drs. George Pearson and William Woodville began to support vaccination among their patients. Jenner conducted a nationwide survey in search of proof of resistance to smallpox or to variolation among persons who had cowpox. The results of this survey confirmed his theory.
Despite errors, many controversies, and chicanery, the use of vaccination spread rapidly in England, and by the year 1800, it had also reached most European countries.
Although sometimes embarrassed by a lack of supply, Jenner sent vaccine to his medical acquaintances and to anyone else who requested for it. After introducing cowpox inoculation in their own districts, many recipients passed the vaccine on to others.
Dr. John Haygarth (of Bath, Somerset) received the vaccine from Edward Jenner in 1800 and sent some of the material to Benjamin Waterhouse, professor of physics at Harvard University.
Waterhouse introduced vaccination in New England and then persuaded Thomas Jefferson to try it in Virginia. Waterhouse received great support from Jefferson, who appointed him vaccine agent in the National Vaccine Institute, an organization set up to implement a national vaccination program in the United States.
Although he received worldwide recognition and many honours, Jenner made no attempt to enrich himself through his discovery. He actually devoted so much time to the cause of vaccination that his private practice and his affairs suffered severely. The extraordinary value of vaccination was publicly acknowledged in England, when in 1802 the British Parliament granted Edward Jenner the sum of ħ 10,000.
Five years later the Parliament awarded him ħ 20,000 more. However, he not only received honours but also found himself subjected to attacks and ridicule. Despite all this, he continued his activities on behalf of the vaccination program. Gradually, vaccination replaced variolation, which became prohibited in England in 1840.
Jenner married in 1788 and fathered four children. On January 23, 1823, he visited his last patient, a dying friend. The next morning Jenner failed to appear for breakfast; later that day he was found dead in his study. He had had a massive stroke. Edward Jenner died during the early morning hours of Sunday, January 26, 1823.
Summary of Important Contributions:
Jenner’s work represented the first scientific attempt to control an infectious disease by the deliberate use of vaccination. Strictly speaking, he did not discover vaccination but was the first person to confer scientific status on the procedure and to pursue its scientific investigation. During the past years, there has been a growing recognition of Benjamin Jesty (1737-1816) as the first to vaccinate against smallpox.
When smallpox was present in Jesty’s locality in 1774, he was determined to protect the life of his family. Jesty used material from udders of cattle that he know had cowpox and transferred the material with a small lancet to the arms of his wife and two boys.
The trio of vaccinees remained free of smallpox, although they were exposed on numerous occasions in later life. Benjamin Jesty was neither the first nor the last to experiment with vaccination. In fact, the use of smallpox and cowpox was widely known among the country physicians in the dairy counties of 18th-century England.
However, the recognition of these facts should not diminish our view of Jenner’s accomplishments. It was his relentless promotion and devoted research of vaccination that changed the way medicine was practised.
Late in the 19th century, it was realized that vaccination did not confer lifelong immunity and that subsequent revaccination was necessary. The mortality from smallpox had declined, but the epidemics showed that the disease was still not under control. In the 1950s a number of control measures were implemented, and smallpox was eradicated in many areas in Europe and North America.
The process of worldwide eradication of smallpox was set in motion when the World Health Assembly received a report in 1958 of the catastrophic consequence of smallpox in 63 countries. In 1967, a global campaign was begun under the guardianship of the World Health Organization and finally succeeded in the eradication of smallpox in 1977.
On May 8, 1980, the World Health Assembly announced that the world was free of smallpox and recommended that all countries cease vaccination.
Scientific advances during the two centuries since Edward Jenner performed his first vaccination on James Phipps have proved him to be more right than wrong. The germ theory of disease, the discovery and study of viruses, and the understanding of modern immunology tended to support his main conclusions.
The discovery and promotion of vaccination enabled the eradication of smallpox this is Edward Jenner’s ultimate vindication and memorial.
Eminent Microbiologist # 3. Louis Pasteur (1822-1895):
Pasteur was a French chemist and biologist who proved the germ theory of X disease and invented the process of pasteurisation.
Louis Pasteur was born on December 27, 1822 in Dole in the Jura region of France. His father was a tanner. In 1847 he earned a doctorate from the Ecole Normale in Pairs. After several years of research and teaching in Dijon and Strasbourg, in 1854 Pasteur was appointed professor of Chemistry at the University of Lille.
Part of the remit of the faculty of sciences was to find solutions to the practical problems of local industries, particularly the manufacture of alcoholic drinks.
He was able to demonstrate that organisms such as bacteria were responsible for souring wine and beer (he later extended his studies to prove that milk was the same), and that the bacteria could be removed by boiling and then cooling the liquid. The process is now called pasteurisation, (partial killing of microbes).
Pasteur then undertook experiments to find where these bacteria came from, and was able to prove that they were introduced from the environment. This was disputed by scientists who believed that they could spontaneously generate. In 1864, the French Academy of Sciences accepted Pasteur’s results. By 1865, Pasteur was director of scientific studies at the Ecole Normale, where he had studied.
He was asked to help the silk industry in southern France, where there was an epidemic amongst the silkworms. With no experience of the subject, Pasteur identified parasitic infections as the cause and advocated that only disease-free eggs should be selected. The industry was saved.
Pasteur’s various investigations convinced him of the Tightness of the germ theory of disease, which holds that germs attack the body from outside. Many felt that such tiny organisms as germs could not possibly kill larger ones such as humans. Pasteur now extended this theory to explain the causes of many diseases – including anthrax, cholera, TB and smallpox – and their prevention by vaccination.
He is best known for his work on the development of vaccines of rabies. In 1888, a special institute was founded in Paris for the treatment of diseases. It became known as the institute Pasteur. Pasteur was its director until his death on 28 September 1895. He was a national hero and was given a state funeral.
Eminent Microbiologist # 4. Robert Koch (1843- 1910):
Robert Koch was born on December 11,1843, at Clausthal in the Upper Harz Mountains.
In 1862 Koch went to the University of Gottingen to study medicine. Here the Professor of Anatomy was Jacob Henle and Koch was, no doubt, influenced by Henle’s view, published in 1840, that infectious diseases were caused by living parasitic organisms. After taking his M.D. degree in 1866, Koch went to Berlin for six months of chemical study and there came under the influence of Virchow.
In 1867 he settled, after a period as Assistant in the General Hospital at Hamburg, in general practice, first at Langenhagen and soon after, in 1869, at Rackwitz, in the Province of Posen. Here he passed his District Medical Officer’s Examination.
In 1870 he volunteered for service in the Franco-Prussian war and from 1872 to 1880 he was District Medical Officer for Wollstein. It was here that he carried out the epoch-making researches which placed him at one step in the front rank of scientific workers.
Anthrax was, at that time, prevalent among the farm animals in the Wollstein district and Koch, although he had no scientific equipment and was cut off entirely from libraries and contact with other scientific workers, embarked, in spite of the demands made on him by his busy practice, on a study of this disease.
His laboratory was the 4-roomed flat that was his home, and his equipment, apart from the microscope given to him by his wife, he provided for himself. Earlier the anthrax bacillus had been discovered by Pollender, Rayer and Davaine, and Koch set himself to prove scientifically that this bacillus is, in fact, the cause of the disease.
He inoculated mice, by means of home-made slivers of wood, with anthrax bacilli taken from the spleens of farm animals that had died of anthrax, and found that these mice were all killed by the bacilli, whereas mice inoculated at the same time with blood from the spleens of healthy animals did not suffer from the disease.
This confirmed the work of others who had shown that the disease can be transmitted by means of the blood of animals suffering from anthrax.
But this did not satisfy Koch. He also wanted to know whether anthrax bacilli that had never been in contact with any kind of animal could cause the disease. To solve his problem he obtained pure cultures of the bacilli by growing them on the aqueous humour of the ox’s eye.
By studying, drawing and photographing these cultures, Koch recorded the multiplication of the bacilli and noted that, when conditions are unfavourable to them, they produce inside themselves rounded spores which can resist adverse conditions, especially lack of oxygen and that, when suitable conditions of life are restored, the spores give rise to bacilli again.
Koch grew the bacilli for several generations in these pure cultures and showed that, although they had had no contact with any kind of animal, they could still cause anthrax.
The results of this painstaking work were demonstrated by Koch to Ferdinand Cohn, Professor of Botany at the University of Breslau, who called a meeting of his colleagues to witness this demonstration, among whom was Professor Cohnheim, Professor of Pathological Anatomy.
Both Cohn and Cohnheim were deeply impressed by Koch’s work and when Cohn, in 1876, published Koch’s work in the botanical journal of which he was the editor, Koch immediately became famous.
He continued, nevertheless, to work at Wollstein for further four years and during this period he improved his methods of fixing, staining and photographing bacteria and did further important work on the study of diseases caused by bacterial infection of wounds, publishing his results in 1878. In this work he provided, as he had done with anthrax, a practical and scientific basis for the control of these infections.
Koch was still, however, without adequate quarters or conditions for his work and it was not until 1880, when he was appointed a member of the Imperial Health Bureau in Berlin, that he was provided, first with a narrow, inadequate room, and later with a better laboratory, in which he could work with Loeffler, Gaffky and others, as his assistants.
Here Koch continued to refine the bacteriological methods he had used in Wollstein.
He invented new methods of cultivating pure cultures of bacteria on solid media such as potato, and on agar kept in the special kind of flat dish invented by his colleague Petri, which is still in common use. He also developed new methods of staining bacteria which made them more easily visible and helped to identify them.
The result of all this work was the introduction of methods by which pathogenic bacteria could be simply and easily obtained in pure culture, free from other organism and by which they could be detected and identified. Koch also laid down the conditions, known as Koch’s postulates, which must be satisfied before it can be accepted that particular bacteria cause particular disease.
Some two years after his arrival in Berlin Koch discovered the tubercle bacillus and also a method of growing it in pure culture. In 1882 he published his classical work on this bacillus.
He was still busy with work on tuberculosis when he was sent, in 1883, to Egypt as Leader of the German Cholera Commission, to investigate an outbreak of cholera in that country. Here he discovered the vibrio that causes cholera and brought back its pure cultures to Germany. He also studied cholera in India.
On the basis of his knowledge of biology and mode of distribution of Cholera vibrio Koch formulated rules for the control of epidemic of cholera which were approved by the Great Powers in Dresden in 1893 and formed the basis of the methods of control which are still used today.
His work on cholera, for which a Prize of 100,000 German Marks was awarded to him, also had an important influence on plans for the conservation of water supplies.
In 1885 Koch was appointed Professor of Hygiene in the University of Berlin and Director of the newly established Institute of Hygiene in the University there. In 1890 he was appointed Surgeon General Class I and Freeman of the City of Berlin.
In 1891 he became an Honorary professor of the Medical Faculty of Berlin and Director of the new Institute for Infectious diseases, where he was fortunate to have among his colleagues, such men as Ehrlich, Von Behring and Kitasato, who themselves made great discoveries.
During this period Koch returned to his work on tuberculosis. He sought to arrest the disease by means of preparation, which he called tuberculin, made from cultures of Tubercle bacilli. He made two preparations of this kind called the old and the new tuberculin respectively, and his first communication on the old tuberculin aroused considerable controversy.
Unfortunately, the healing power that Koch claimed for this preparation was greatly exaggerated and, because hopes raised by it were not fulfilled, opinion went against it and against Koch.
The new tuberculin was announced by Koch in 1896 and the curative value of this also was disappointing; but it led, nevertheless, to the discovery of substances of diagnostic value. While this work on tuberculin was going on, his colleagues at the Institute for Infectious Diseases, von Behring, Ehrlich and Kitasato, carried out and published their epoch-making work on the immunology of diphtheria.
In 1896 Koch went to South Africa to study the origin of rinderpest and although he did not identity the cause of this disease, he succeeded in limiting its outbreak by injection into healthy farm-stock of bile taken form the gall bladder of infected animals.
Then followed the work in India and Africa on malaria, black-water fever, surra of cattle and horses and plague, and the publication of his observations on these diseases in 1898. Soon after his return to Germany he was sent to Italy and the tropics where he confirmed the work of Sir Ronald Ross on malaria and did useful work on the aetiology of the different forms of malaria and their control with quinine.
In was during these later years of his life that Koch came to the conclusion that the bacilli that cause human and bovine tuberculosis are not identical and his statement of this view at the International Medical Congress on Tuberculosis in London in 1901 caused much controversy and opposition; but it is now known that Koch’s view was right.
His work on typhus led to the idea, then a new one, that this disease is transmitted much more often from man to man then from drinking water and this led to new control measures.
In December, 1904, Koch was sent to East Africa to study East Coast fever of cattle and he made important observation, not only on this diseases but also on pathogenic species of Babesia and Trypanosoma and on tickborne spirochaetosis, continuing his work on these organism when he returned home.
Koch was the recipient of many prizes and medals, honorary, doctorates of the Universities of Heidelberg and Bologna, honorary citizenships of Berlin, Wollstein and his native Clausthal and honorary memberships of learned societies and academies in Berlin, Vienna, Posen, Perugia, Naples and New York.
He was awarded the German Order of the Crown, the Grand Cross of the German Order of the Red Eagle (the first time this high distinction was awarded to a medical man), and Orders from Russia and Turkey. Long after his death, he was posthumously honoured by memorials and in other ways in several countries.
In 1905 he was awarded the Nobel Prize for Physiology or Medicine. In 1906, he returned to Central Africa to work on the control of trypanosomiasis, and there he reported that atoxyl is as effective against this disease as quinine is against malaria. Thereafter Koch continued his experimental work on bacteriology and serology. Dr. Koch died on May 27, 1910, in Baden-Baden.
The steps of Koch’s postulates used to relate a specific micro-organ disease, (a) Micro-organisms are observed in a sick animal and (b) Lab. (c) The organisms are injected into a healthy animal, and (d) Animal develops the disease, (e) The organisms are observed in the sick animal and (f) Reisolated in the lab.
Eminent Microbiologist # 5. M.W. Beijerinck (1851-1931):
He was born on the 16th of March, 1851 in Amsterdam, Netherlands. He studied chemical engineering at the Delft Polytechnic. Later he established the Delft School of Microbiology.
He became famous as the founder of virology. He discovered viruses, by proving in filtration experiments that the tobacco mosaic disease is caused by something smaller than a bacterium.
1898 Beijerinck Discovered viruses, by proving in filtration experiments.
1905 – He received the Leeuwenhoek Medal.
Later he also worked on nitrogen fixation, the process by which diatomic nitrogen gas is converted to ammonium.
1931-Martinus Williem Beijerinck died on the 1st of January.
Scientific Highlights of Beijerinck’s Career:
1. Demonstrated the filterability of the infectious agent of tobacco mosaic disease and coined the term “filterable virus”. Described the intracellular reproduction of tobacco mosaic virus (TMV) in 1898, a pioneering contribution to virology.
2. Isolated Bacillus radicicola and proved that it forms nodules on the roots of Leguminosae species. Later isolated Rhizobium species, studied nitrogen fixation, and demonstrated nitrogen fixation by free-living microorganisms, particularly Azotobacter chroococcum.
3. Isolated and described in detail the denitrification process of Bacillus sphaerosporus and Bacillus nitrous.
4. Isolated sulphate producing Thiobacillus species and demonstrated their chemoautotrophic nature. Also studied hydrogen sulphide production by Aerobacter species.
5. Contributed to the understanding of lactic acid bacteria involved in producing kefir and yogurt. Demonstrated the significance of a catalase-negative reaction and proposed the generic name Lactobacillus.
6. Introduced the generic name Acetobacter, described pigment-producing Acetobacter melanogenum, and studied butyric acid and butyl alcohol fermentation.
7. Pioneered the study of luminescent bacteria and isolated Phulobacterium zuminosum (1889). Pioneered the study of yeast, isolated Schizosaccharomyces octoporus from raisins, and discovered the saccharolytic enzyme lactase of Saccharomyces tyrocola.
8. Was the first to obtain pure cultures of algae, zoochlorellae, and gunidia of lichens.
9. Studied urea decomposition, microbial variations (mutations), and oxygen relationship among bacteria.
10. Observed Sarcina ventriculi in media of high acidicity and under anaerobic conditions.
11. Studied plant galls and did extensive morphological work on adventitious structures and regeneration phenomena in plants.
12. Studied phyllotaxis, the arrangement of leaves on plant stems.
13. Investigated the fungus Clasterosporium carpophilum (later named C. beifernick)the potent cause of gummosis.
Eminent Microbiologist # 6. Dimitri Iwanowsky (1864-1920):
He was a Russion botanist and is known for his work on Tobacco mosaic virus (TMV). Prior to his work, Adoey Meyer, a Dutch scientist had demonstrated that infected sap can introduce the disease in the healthier plants. It was after Iwanowsky’s work (1892),that scientists started looking beyond the bacteria that could not be retained by the bacterial filter (Chamberland Candle filter).
This is generally regarded as the beginning of virology.
Eminent Microbiologist # 7. Sergei Nikolaievich Winogradsky (1856-1953):
Sergei Winogradsky was born on September 1,1856 in Kiev, Russia. After an early training in music (studied Piano at St. Petersburg in 1875) he entered University of St. Petersburg in 1877 to study Chemistry under Nikolai Menshchutkin and Botany under Andrei Sergeevich Famintzin.
He did his diploma in 1881 and earned a Masters degree in Botany in 1884. In 1885, he did his earlier work under the renowned botanist Anton de Bary.
He made tremendous contribution to the understanding of sulphur bacteria and studied the oxidation of hydrogen sulphide in natural habitats by sulphur oxidising bacteria in 1887. From these studies he developed the concept of Chemolithotrophy, the oxidation of inorganic compounds resulting in energy.
In 1888, he shifted to Zurich, and worked on the process of nitrification, identifying the genera Nitrosomonas and Nitrosococcus, which oxidised ammonium to nitrite, and Nitrobacter which oxidized nitrite to nitrate.
He not only iosolated nearly pure cultures of nitrifying bacteria but also demonstrated the process of nitrification. He is also credited (1893) for isolating the first anaerobic nitrogen fixing bacterium Clostridium sp. and thus founded the bacterial rules in Nitrogen fixation (and N2 Cycle).
During the period 1891-1905, he returned to St. Petersburg and was appointed Chief, Division of General Microbiology of the Institute of Experimental Medicine. It was during this time that he discovered C. pastorianum. In 1901, he was elected Honorary Member of the Moscow Society of Natural Sciences, and in 1902, corresponding member of the French Academy of Sciences.
After his retirement form active service in 1905, again he took an invitation to be the head, Division of Agricultural Bacteriology at the Pasteur Institute at an experimental station at Brie-Comte-Robert, France about 30 km. from Paris.
During this tenure of his stay he worked on a number of topics including, iron bacteria, nitrifying bacteria, nitrogen fixation by Azotobacter, cellulose decomposing bacteria and culture methods for micro-organisms.
As he was attempting to grow and understand the microbial world, away from where they exist or different from the medical context, he is amongst the pioneer students of Environmental Microbiology and Microbial Ecology. His monograph, Microbiologie de sol (Soil Microbiology) is an original piece of work with drawings of many organisms.
He had also created a Jar for observing growth of various microbes. This Jar is also called Winogradsky’s Column. It is employed to study growth of microbes and their physiological activities.
Winogradky is best known for discovering Chemoautotrophy, which soon became popularly known as Chemosynthesis, the process by which organisms derive energy from a number of different inorganic compounds and obtain carbon in the form of Carbon dioxide.
Thus he broke the previous belief that autotrophic organisms obtained their energy solely from light and not from reactions of inorganic chemical compounds. Winogradsky retired from active life in 1940 and after working for a long span and publishing some very useful research works died on 25th February, 1953, in Brie-Comte-Robert, France.
He is also known to have influenced the famous workers like Selman Waksman and Martinus Beijerinck.
Eminent Microbiologist # 8. Alexander Fleming (1881-1955):
Alexander Fleming was born in a remote, rural part of Scotland. The seventh of eight siblings and half-siblings, his family worded an 800-acrefarm a mile “from the nearest house”. The Fleming children spent much of their of time ranging through the streams, valleys, and moors of the countryside. “We unconsciously learned a great deal from nature, “said Fleming.
When their father died, Fleming’s eldest brother inherited the running of the farm. Another brother Tom had studied medicine and was opening a practice in London. Soon, four Fleming brother and a sister were living together in London. Alec, as he was called, had moved to London when he was about 14, and went to the Polytechnic School in Regent Street. Tom encouraged him to enter business.
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After completing school he was employed by a shipping firm, though they didn’t much like it. In 1900, when the Boer War broke out between the United Kingdom and its colonies in southern Africa, Alec and two brothers joined a Scottish regiment. This turned out to be as much a sporting club as anything; they honed their shooting, swimming, and even water polo skills, but never went to the Transvaal.
Soon after this, the Fleming’s uncle died and left them each 250 pounds. Tom’s medical practice was now thriving and he encouraged Alec to put his legacy toward the study of medicine.
Fleming took top scores in the qualifying examinations, and had his choice of medical schools. He lived equally close to three different schools, and knowing little about them, chose St. Mary’s because he had played water polo against them. In 1905 he found himself specializing as a surgeon for almost as random a reason.
His switch to bacteriology was even more surprising; if he took a position as a surgeon, he would have improve his team. Knowing that Fleming was a great shot he did all he could to keep him at St. Mary’s . He worked in the Inoculation Service and he convinced Fleming to join his department in order to work with its brilliant director- and to join the rifle club. Fleming would stay at St. Mary’s for the rest of his career.
In 1909 German chemist-physician Paul Ehrlich developed a chemical treatment for syphilis. He had tried hundreds of compounds, and the six hundred and sixth worked. IT was named salvarsan (meaning “that which saves by arsenic”). The only previous treatments for this disease had been so toxic as to often kill the patient.
Ehrlich brought news of his treatment to London, where Fleming became one very few physicians to administer salvarsan. He did so with the new and difficult technique of intravenous injection. He soon developed such a busy practice he got the nickname “Private 606.”
When World War I broke out, most of the staff of the bacteriology lab went to France to set up a battlefield hospital lab. Here, they encountered infections so drastic that soldiers quickly died from them. Yet they were still simple infections.
Fleming felt there must be something, a chemical like salvarsan that could help fight microbe infection even in wounds caused by exploding shells. During the course of the war. Fleming made many innovations in treatment of the wounded, but this was soon overshadowed by the work he did afterwards.
Back in St. Mary’s lab in the 1920s, Fleming searched for an effective antiseptic. He discovered lysozyme, an enzyme occurring in many body fluids, such as tears. It had a natural antibacterial effect, but no against the strongest infectious agents. He kept looking. Fleming had so much going on in his lab that it was often in a jumble. This disorder proved very fortunate.
In 1928 he was straightening up a pile of Petri dishes where he had been growing bacteria, but which had been piled in the sink. He/opened each one and examined it before tossing it into the cleaning solution. One made him stop and say, “That’s funny.”
Some mold was growing on one of the dishes—not too unusual-but all around the mold, the staph bacteria had been killed—very unusual. He took a sample of, the mold.
He found that it was form the penicillium family, later specified as penicillium notatum. Fleming presented his findings in 1929, but raised little interest. He published a report on penicillin and its potenitial uses in the British Journal of Experimental Pathology. Fleming worked with the mold for some time, but refining and growing it was a difficult process better suited to chemists.
The work was taken over by a team of chemists and mold specialists, but was cut short when several of them died or relocated. It took World War II to revitalize interest in penicillin, and Howard Florey and Einst Cham picked up the work.
In recognition for his contribution, Alexander Fleming was knighted in 1944. With Chain and Florey he was awarded the Nobel Prize in 1945.
“One sometimes finds what one is not looking for.”
