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History of Microbiology
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Introduction of History of Microbiology
Microbiology, study of microorganisms, or microbes, a diverse group of minute, simple life-forms that include bacteria, archaea, algae, fungi, protozoa, and viruses. The field deals with the structure, function, and classification of these organisms and with ways of exploiting and controlling their activities. The living forms discovered in the 17th century, which existed but could not be seen with the naked eye was an important landmark in the history of science. From the 13th century it was believed that living unseen entities caused decay and disease. In the last quarter of the 19th century the word microbe was coined to describe these organisms. In due course microbiology developed into a specialized branch of science, the microbes were found to be a very large group of extremely varied organisms. Our daily life is interwoven with microorganisms. Microbes are abundantly found in the soil, in the seas, and in the air, in addition to populating both the inner and outer surfaces of the human body. Microorganisms are unfavourable, as when they cause decay of materials or spread diseases, and are favourable, when they ferment sugar to beer and wine, cause bread to rise, add flavour to cheeses, and produce important products such as antibiotics and insulin. Microorganisms are of infinite value to Earth’s ecology. They disintegrate animal and plant remains and convert those to simpler substances that can be recycled. Microbiology basically began with the development of the microscope. Although others may have seen microbes before him, it was Leeuwenhoek, who was the first to provide proper records of his observations. History of Microbiology
Antonie van Leeuwenhoek (24 October, 1632 – 26 August, 1723) was a Dutch cloth merchant who literally made hundreds of microscopes. Although compound lenses were invented at that time, they were not perfect, and so his microscopes worked on a very simple magnification system. He used a microscope containing improved lenses that could magnify objects almost 300-fold, or 270x. Under these microscopes, Leeuwenhoek found motile objects. Leeuwenhoek worked on his tiny lenses that led to the building of his microscopes which are considered to be the first practical ones. They had little resemblance to today’s microscopes, as they were more like very high-powered magnifying glasses and operated on one lens instead of two.
Antonie Van Leeuwenhoek discovered “protozoa” – the single celled organisms and called them “animalcules”. He further improved the microscope and laid foundation for microbiology. He is often cited as the first microbiologist to study muscle fibres, bacteria, spermatozoa and blood flow in capillaries. He was largely a self-taught man in science, commonly known as Father of Microbiology. Antonie Van Leeuwenhoek is best known for his pioneering work in microscopy. His contributions towards the establishment of microbiology as a scientific discipline are well recognised. History of Microbiology
Robert Hooke (July 18, 1635–March 3, 1703) was a 17th century “Natural philosopher”, a scientist, known for a variety of observations of the natural world. His most notable discovery came in 1665 when he observed a slice of cork through a microscope lens and discovered cells. Robert Hooke did aamassive work in microbiology. The cell was first discovered and named by Robert Hooke in 1665. He noted that it looked similar to cellula or small rooms. He coined the term “cell” from the Latin cella, which means “small room”. However what Hooke actually saw was the dead cell walls of plant cells (cork) as it appeared under the microscope. English scientist Robert Hooke improved the microscope, and observed the structure of snowflakes, fleas, lice and plants. Hooke published the first ever scientific best seller: Micrographia which included sketches of various natural things as observed under a microscope. He further improved the microscope by providing it with illumination. He placed a water-lens beside the microscope to focus light from an oil lamp on to his specimens to illuminate them brightly.
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[I] Louis Pasteur (December 27, 1822 – September 28, 1895):
He was a French biologist, microbiologist and chemist known for discovering the principles of vaccination, microbial fermentation and pasteurization. His discoveries have saved many lives ever since breakthroughs in the causes and prevention of diseases. He succeeded in reducing mortality from fever. He created the first vaccines for rabies and anthrax.
Contributions of Louis Pasteur in Fermentation:
Pasteur laid foundation for all microbiological techniques through his research on lactic and alcoholic fermentation and defined these principles:
1. All fermentation is caused by a microorganism.
2. There is a particular ferment for every given fermentation.
3. A sterile culture medium is required for ferment growth.
4. Medium has to be seeded with absolute ferment particles.
In the 1850s and 1860s, Louis Pasteur showed that fermentation was a process initiated by living organisms in a series of investigations. At the time it was thought to be caused by yeast dying and decomposing. In 1858, Pasteur demonstrated that fermentation was a process involving the action of living yeast and that fermentation could also produce lactic acid, which makes wines sour. Through further research, Pasteur showed that the growth of micro-organisms was responsible for spoiling beverages, such as beer, wine and milk.
History of Microbiology
Contributions of Louis Pasteur in Rabies:
Development of vaccine against rabies or hydrophobia was the last and the most famous success in the long career of Pasteur’s research. Rabies attacked the nervous system and it was considered a dreadful disease for its symptoms and treatment. At first, Even Pasteur failed to find and isolate the causative agent, but with his excellent experimental method he built an invisible micro-organism to attenuate the virulence. He attenuated the microorganism by growing it in abnormal host i.e. rabbit marrow successfully. After the death of the rabbit the brain and the spinal cord of the rabbit were removed and dried. The dried preparation of brain was used as vaccine. Then, for the first time on July 6th, 1885, he treated 9 years old Joseph Meister with his anti-rabies vaccine and the kid recovered perfectly. This milestone transformed Pasteur into a legend.
History of Microbiology
Contributions of Louis Pasteur in Pasteurization:
Pasteur continued his research and applied his microbiological techniques to agricultural and industrial sectors successfully. His pasteurization process concluded that all fermentable liquid could be prevented from spoiling with a special heating treatment. This method was particularly implemented to save wines and beers from spoilage by heating at 55 °C. After studying the harmful effects of microbes on foodstuffs, Louis Pasteur invented the pasteurization process in 1862. In pasteurization, liquids such as milk are heated to a temperature between 60 °C and 100 °C to kill microorganisms present within and causing spoilage. Pasteurization was first used to save the French wine industries from the problem of contamination. Soon the process was also applied to milk and beer. Pasteurization continues to be used widely in the dairy industry and other food processing industries to achieve food preservation and food safety.
History of Microbiology
Contributions of Louis Pasteur (1822-1895):
Disproved the Spontaneous Generation theory. Different microbes gives different tastes to wine. He selected a particular strain of yeast for high quality wine. He demonstrated the virulence of bacteria. . Discovered the fermentation fruit to alcohol by microbes – This was the beginning of Fermentation. He developed a method to remove the undesired microbes from juice without affecting its quality. Heating the juice at 62.8°C for half an hour resulted in removal of microbes. This technique is called as Pasteurization, which is commonly used in milk industry. . He discovered that parasites (protozoa) cause pebrine disease of silk worm. He suggested that disease free caterpillars can eliminate the disease. . He isolated the anthrax causing bacilli from the bloods of cattle, sheep and human being. He developed vaccine against rabbies from the brains and spinal cord of rabbit.
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[II] Heinrich Hermann Robert Koch (11 December 1843 27 May 1910):
Rober Heinrich was a German physician and microbiologist. As one of the main founders of modern bacteriology, he identified the specific causative agents of tuberculosis, cholera, and anthrax and gave experimental support for the concept of infectious disease which included experiments on humans and other animals. Koch created and improved laboratory techniques in the field of microbiology, and made key discoveries in public health. His research led to the creation of Koch’s postulates, a series of four generalized principles linking specific microorganisms to specific diseases. These remain today as standard in medical microbiology. For his research on tuberculosis, Koch received the Nobel Prize in Medicine in 1905. The Robert Koch Institute is named in his honour.
History of Microbiology
Koch’s Germ Theory of Disease:
Before Pasteur effective treatments for many diseases were discovered by trial and error though the cause of disease was unknown. The discovery of crucial role of yeast in fermentation made scientists to think about the possibilities of microbes acting as causative agents. Koch was of the opinion that germs i.e. microbes cause disease in plants and animals. This idea is known as germ theory of disease. The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or “germs” can lead to disease. Koch’s postulates were developed in the 19th century as general guidelines to identify pathogens. It was recognized even in Koch’s time that some infectious agents were undoubtedly responsible for disease even though they did not fulfil all of the postulates. Currently, a number of infectious agents are accepted as the cause of disease even if do not fulfil all of Koch’s postulates.
History of Microbiology
Koch’s Postulates:
1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism.
4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
While Koch’s postulates retain historical importance and continue to be an approach to microbial diagnosis, fulfilment of all four postulates is not required to demonstrate the factor. Koch’s postulates have also influenced scientists who examine microbial pathogenesis from a molecular point of view. In the 1980s, a molecular version of Koch’s postulates was developed to guide the identification of microbial genes encoding virulence factors.
History of Microbiology
Koch and Tuberculosis:
At the time, it was widely believed that tuberculosis was an inherited disease. However, Koch was convinced that the disease was caused by a bacterium and was infectious. He tested his four postulates using guinea pigs. The results of these experiments, showed that his experiments with tuberculosis satisfied all four of his postulates. In 1882, he published his findings on tuberculosis. In that he reported the causative agent of the disease to be the slow-growing Mycobacterium tuberculosis. Koch’s attempt at developing a drug to treat tuberculosis, tuberculin, was a failure later. He did not disclose the exact composition, but the treatment he claimed did not materialize. And the same substance is used for tuberculosis diagnosis today.
History of Microbiology
Koch and Cholera:
Koch next turned his attention to cholera, and began to conduct research in Egypt in the hopes of isolating the causative agent of the disease. However, he was not able to complete the task before the epidemic in Egypt ended, and subsequently travelled to India to continue with the study. In 1884 in India, Koch was able to determine the causative agent of cholera and isolating Vibrio cholerae.
Contributions of Robert Koch (1843-1910):
Discovery of Bacillus anthracis, the causative agent of anthrax. of Discovery of Vibrio cholerae the causative agent of cholera. Use of gelatine as the solidifying agent. Described the sporulation and germination of bacterial endospores. Described the thermo resistance and appearance of endospores. Discovery of nutrient broth and nutrient agar. Adaptation of meat infusion as basic ingredient of culture media. Development of methods of stained bacterial smears. Discovery of Mycobacterium tuberculosis the causative agent tuberculosis. Invented the streak plate technique. Development of methods of microscopic observation of bacterial cells in live state.
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[III] Ferdinand Cohn (1828-1898):
Ferdinand Cohn considered to be the father of modern Bacteriology, began his studies as a botanist and ultimately made discoveries which led to the creation of a new field of study. He was the first scientist who believed that bacteria should be classified as plants. Cohn was first to show that Bacillus can change from a vegetative state to an endospore state when subjected to an environment unfavorable to the vegetative state. His studies laid the foundation for the classification of microbes. These gave some of the first insights into the incredible complexity and diversity of microbial life. In 1892, Dmitry Ivanovsky used filters to show that sap from a diseased tobacco plant despite having been filtered remained infectious to healthy tobacco plants. Martinus Beijerinck called the filtered, infectious substance a “virus”. This discovery is considered to be the beginning of virology.
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[IV] Thomas Milton Rivers (September 3, 1888 – May 12, 1962):
Thomas Milton Rivers was an American bacteriologist and virologist. The “Father of modern virology” put forth the River’s Postulates for pathogenesis of viral diseases. The viral agent must be found either in the host’s (animal or plant) body fluids at the time of disease or in cells showing lesions specific to that disease. The host material with the viral agent used to inoculate the healthy host (test organism) must be free of any other microorganism. . The viral agent obtained from the infected host must produce the specific disease in a suitable healthy host and/or provide evidence of infection by inducing the formation of antibodies specific to that agent. Similar material (viral particle) from the newly infected host (test organism) must be isolated and capable of transmitting the specific disease to other healthy hosts.
[V] Joseph Lister, (5 April 1827 – 10 February 1912):
Joseph Lister, known between 1883 and 1897 as Sir Joseph Lister, Bt., was a British surgeon and a pioneer of antiseptic surgery. Lister promoted the idea of sterile surgery. Lister successfully introduced carbolic acid (now known as phenol) to sterilize surgical instruments and to clean wounds. He developed the practice of spraying phenol in an operative room to control infection. He proposed use of heat sterilized surgical instruments during operation. Applying Louis Pasteur’s advances in microbiology, Lister mastered the use of carbolic acid as an antiseptic. It became the first widely used antiseptic in surgery. He first suspected it would prove an adequate disinfectant because it was used to eliminate the stink from fields irrigated with sewage waste. He presumed it to be safe because fields treated with carbolic acid produced no apparent ill-effects on the livestock that later grazed upon them. Lister’s work led to a reduction in post-operative infections and made surgery safer for patients, distinguishing him as the “father of modern surgery”. The term antiseptic or surgical antisepsis was further coined for this concept which was immediately accepted. He is also known to be the first to obtain the pure cultures of bacteria by using serial dilutions of liquid media.
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[VI] Paul Ehrlich (14 March 1854 – 20 August 1915):
Paul Ehrlich was a Nobel prize-winning German-Jewish physician and scientist who worked in the fields of haematology, immunology, and antimicrobial chemotherapy. Ehrlich popularized the concept of a magic bullet. He also made a decisive contribution to the development of an antiserum to combat diphtheria and conceived a method for standardizing therapeutic serums. In 1908, he received the Nobel Prize in Physiology or Medicine for his contributions to immunology. Ehrlich reasoned that if a compound could be made such that it selectively targeted a disease-causing organism, then a toxin for that organism could be delivered along with the agent of selectivity. Hence, a “magic bullet” would be created that killed only the organism targeted. Ehrlich discovered in 1909 that Compound 606, Arsphenamine, effectively combated “spirillum” spirochetes bacteria, one of whose subspecies causes syphilis. The compound proved to have few side effects in human trials, and the spirochetes disappeared in seven syphilis patients after this treatment. The theory included Ehrlich’s first use of the term “magic bullet”: the concept that chemicals could be designed to bind and kill specific microbes or tumor cells. Ehrlich’s thoughts on defence against bacteria had turned to chemical aspects, and he was investigating what he called chemotherapy the cure of bacterial infections with substances of known chemical identity. Chemists could synthesize compounds that would have effect only on the parasites which attack the body. These synthetic remedies would work as magic bullets that automatically found their target without causing any harmful side effects. Ehrlich’s methodological way of looking for therapeutically useful substances resulted in the first great breakthrough in the treatment of the dreaded venereal disease syphilis. It was Ehrlich who coined the term magic bullet to mean a chemical bullet that would kill the microorganism but not the patient. Salvarsan was the first drug with practically chemotherapeutic activity. Ehrlich’s hope that salvarsan would kill the spirochete that causes syphilis was too optimistic, but the power of the drug was undoubted and attracted the name magic bullet. After extensive clinical testing the Hoechst company began to market the compound toward the end of 1910 under the name Salvarsan. This was the first agent with a specific therapeutic effect to be created on the basis of theoretical considerations. Salvarsan proved to be amazingly effective, particularly when compared with the conventional therapy of mercury salts. Manufactured by Hoechst AG, Salvarsan became the most widely prescribed drug in the world. It was the most effective drug for treating syphilis until penicillin became available in the 1940s. Salvarsan required improvement as to side effects and solubility and was replaced in 1911 with Neosalvarsa. Among the results achieved by Ehrlich and his research colleagues was the insight that when tumors are cultivated by transplanting tumor cells, their malignancy increases from generation to generation. Ehrlich applied bacteriological methods to cancer research. In analogy to vaccination, he attempted to generate immunity to cancer by injecting weakened cancer cells. The first notable contribution Ehrlich made to science was in the field of hematology. Working from the observation that the uptake of different dyes varied in different tissues, Ehrlich proposed that a true chemical reaction occurred in the staining of cells. He identified mast cells, created the field of differential staining of blood cells, and defined neutrophils, eosinophils, basophils, lymphocytes, erythrocytes and reticulocytes based on a preference toward acidic or basic dyes.
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[VII] Ilya Ilyich Mechnikov (3 May 1845 – 15 July 1916):
Ilya Ilyich Mechnikov was a Ukrainian and Russian zoologist best known for his pioneering research in immunology. In particular, to his credit is the discovery of phagocytes (macrophages) in 1882. This discovery turned out to be the major defence mechanism in innate immunity. He discovered phagocytosis after experimenting the larvae of starfish. In 1882, he first demonstrated the process. He inserted small citrus thorns into starfish larvae, and then found unusual cells surrounding the thorns. He realized that in the animals which have blood, the white blood cells gather at the site of inflammation. He put forth the hypothesis that this could be the process by which bacteria were attacked and killed by the white blood cells. His theory, that certain white blood cells could engulf and destroy harmful bodies such as bacteria. This met with doubts from leading specialists in 1887. He observed that leukocytes isolated from the blood of various animals were attracted towards certain bacteria. Mechnikov’s early observation, then, was the foundation for studies that defined a critical mechanism. In this, the bacteria attract leukocytes to initiate and direct the innate immune response of acute inflammation to sites of host invasion by pathogens. – Mechnikov also developed a theory that aging is caused by toxic bacteria in the gut and that lactic acid could prolong life.
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[VIII] Edward Jenner, (17 May 1749 – 26 January 1823):
Edward Jenner, was an English physician and scientist who was the pioneer of smallpox vaccine, the world’s first vaccine. The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow), the term devised by Jenner to denote cowpox. He used it in 1796 when he described the protective effect of cowpox against smallpox. Jenner is often called “the father of immunology”. His work is said to have “saved more lives than the work of any other human”. In Jenner’s time, smallpox killed around 10% of the British population. The number was as high as 20% in towns and cities where infection spread more easily. He was the member of the Royal Society. He was the first person to describe the brood parasitism of the cuckoo in the field of zoology. A common observation that milkmaids were generally immune to smallpox, Jenner postulated that the pus in the blisters that milkmaids received from cowpox (a disease similar to smallpox, but much less virulent) protected them from smallpox. On 14 May 1796, Jenner tested his hypothesis by inoculating James Phipps, an eight-year-old boy who was the son of Jenner’s gardener. He scraped pus from cowpox blisters on the hands of, a milkmaid who had caught cowpox from a cow. Jenner inoculated Phipps in both arms that day, subsequently producing in Phipps a fever and some uneasiness, but no full-blown infection. Later, he injected Phipps with variolous material, the routine method of immunization at that time. No disease followed. The boy was later challenged with variolous material and again showed no sign of infection. Jenner’s vaccine laid the foundation for contemporary discoveries in immunology. This was the first successful vaccine ever to be developed and remains the only effective preventive treatment for the fatal smallpox disease.
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[IX] Sir Alexander Fleming (6 August 1881 – 11 March 1955):
Sir Alexander Fleming was a Scottish biologist, physician, microbiologist, and pharmacologist. His best-known discoveries are the enzyme lysozyme in 1923 and the world’s first antibiotic substance benzylpenicillin (Penicillin G) from the mould Penicillium notatum in 1928. The simple discovery and use of the antibiotic agent has saved millions of lives. This earned Fleming together with Howard Florey and Ernst Chain, who devised methods for the large-scale isolation and production of penicillin Nobel Prize in Physiology/Medicine in 1945. In 1928, Fleming started with a series of experiments involving the common staphylococcal bacteria. He observed that an uncovered Petri dish placed next to an open window became contaminated with mould spores. Fleming observed that the bacteria close to the mould colonies were dying. This could be seen by the dissolving and clearing of the surrounding agar gel. He was able to isolate the mould. He identified it as a member of the Penicillium genus. He found it to be effective against all Gram-positive pathogens. These pathogens are responsible for diseases such as scarlet fever, pneumonia, gonorrhoea, meningitis and diphtheria. He observed that it was not the mould itself which showed the effect but some ‘juice’ it had produced that had killed the bacteria. He named the ‘mould juice’ as penicillin. Fleming published the discovery of penicillin in the British Journal of Experimental Pathology in 1929. The scientific community greeted his work with little initial enthusiasm. Additionally, Fleming found it difficult to isolate this valuable ‘mould juice’ in large quantities. It was in 1940, just as he was thinking about retirement, that two scientists, Howard Florey and Ernst Chain, became interested in penicillin. In time, they were able to mass-produce it for use during World War II. He wrote many articles on bacteriology, immunology, and chemotherapy.
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[X] Selman Abraham Waksman (July 22, 1888 – August 16, 1973):
Selman Abraham Waksman was a Ukrainian-born, Jewish-American inventor, biochemist and microbiologist whose research into the decomposition by organisms that live in soil enabled the discovery of streptomycin and several other antibiotics. He discovered a number of antibiotics (and introduced the modern sense of that word to name them). He introduced procedures that have led to the development of many others. In 1952, he was awarded the Nobel Prize in Physiology or Medicine for ingenious, systematic and successful studies of the soil microbes that led to the discovery of streptomycin. In 1940 Waksman, along with his graduate student H. Boyd Woodruff, isolated actinomycin from soil bacteria. Although the substance was effective against strains of gram-negative and gram positive bacteria, including M. tuberculosis, it was extremely toxic when given to test animals. Four years later Waksman and graduate students Albert Schatz and Elizabeth Bugie described their discovery of the relatively non-toxic streptomycin, which they extracted from the actinomycete, Streptomyces griseus. They found that the antibiotic exercised suppressive effect on tuberculosis. In combination with other chemotherapeutic agents, streptomycin has become a major factor in controlling the disease. Waksman also isolated and developed several other antibiotics, including neomycin that has been used in treating many infectious diseases of humans, domestic animals, and plants.
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[XI] Martinus Willem Beijerinck (16 March 1851 – 1 January 1931):
Martinus Willem Beijerinck was a Dutch microbiologist and botanist. He is often considered one of the founders of virology and environmental microbiology. In spite of his numerous pioneering and influential contributions to science in general, he was never awarded the Nobel Prize. Beijerinck discovered nitrogen fixation, the process by which diatomic nitrogen gas is converted to ammonium ions and becomes available to plants. Bacteria perform nitrogen fixation; lodging inside root nodules of certain plants (legumes). He isolated Bacillus rudicicola and proved that it forms nodules on the roots of Leguminosae species. Later isolated Rhizobium species, studied nitrogen fixation. In addition to having discovered a biochemical reaction vital to soil fertility and agriculture, Beijerinck revealed the classic example of symbiosis between plants and bacteria. Beijerinck discovered the phenomenon of bacterial sulfate reduction, a form of anaerobic respiration. He learned bacteria could use sulfate as a terminal electron acceptor, instead of oxygen. This discovery has had an important impact on our current understanding of biogeochemical cycles. Spirillum desulfuricans, now known as Desulfovibrio desulfuricans, the first known sulfate-reducing bacterium, was isolated and described by Beijerinck. Beijerinck invented the enrichment culture, a fundamental method of studying microbes from the environment. Enrichment culture is the use of certain growth media to favour the growth of a particular microorganism over others, enriching a sample for the microorganism of interest. This is generally done by introducing nutrients or environmental conditions that only allow the growth of an organism of interest. Enrichment cultures are used to increase a small number of desired organisms to detectable levels. This allows for the detection and identification of microorganisms with a variety of nutritional needs. Enrichment cultures are often used for soil and faecal samples. Through these techniques, he and others could more readily uncover the role of microorganisms in natural processes and better harness these activities to benefit agriculture and industry. The discovery of living organisms that appear under predetermined conditions, either because they alone can develop, or because they are the more fit and win over their competitors. Especially this latter method is the broadest application of the elective culture method. It is fruitful and truly scientific, and the rapid and surprising advances in general microbiology are due to this methodology.
History of Microbiology
Contributions of Beijerinck:
Demonstrated the infectious agent of tobacco mosaic disease is filterable and coined the term “filterable virus.” Described the intracellular reproduction of tobacco mosaic virus in 1898, a pioneering contribution in virology. . Isolated Bacillus rudicicola and proved that it forms nodules on the roots of Leguminosae species. . Isolated Rhizobium species, studied nitrogen fixation, and demonstrated nitrogen fixation by free-living microorganisms, particularly Azotobacter chroococcum. Isolated and described in detail the denitrification process of Bacillus sphaerosporus and Bacillus nitrous. Isolated sulfate producing Thiobacillus species and demonstrated their chemoautotrophic nature. Studied hydrogen sulfide production by Aerubacter species. 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. Introduced the generic name Acetobacter, described pigment producing Acetobaeter melanogenum, and studied butyric acid and butyl alcohol fermentation. Pioneered the study of luminescent bacteria and isolated Phutobacterium zuminosum. Pioneered the study of yeast, isolated Schixosuccharumyces octoporus from raisins, and discovered the saccharolytic enzyme lactase of Saccharomyces tyrucola. First to obtain pure cultures of algae, zoochlorellae, and gonidia of lichens. Studied urea decomposition, microbial variations (mutations), and oxygen relationships among bacteria. Regeneration phenomena in plants. Studied phyllotaxis, the arrangement of leaves on plant stems. Investigated the fungus Czasterusporium carpophilum (later named C. belijernick), the potent cause of gummosis. History of Microbiology
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[XII] Sergei Nikolaievich Winogradsky (1st September 1856 – 25th February 1953):
Sergei Nikolaievich Winogradsky was a Russian microbiologist, ecologist and soil scientist who pioneered the cycle-of-life concept. Winogradsky discovered the first known form of lithotrophy during his research with Beggiatoa in 1887. He reported that Beggiatoa oxidized hydrogen sulfide (H2S) as an energy source forming intracellular sulphur droplets. This research provided the first example of lithotrophy, but not autotrophy. His research on nitrifying bacteria was the first report of the known form of chemoautotrophy. It showed how a lithotroph fixes carbon dioxide (CO2) to make organic compounds. He isolated the first pure cultures of the nitrifying bacteria. He confirmed that they carried out the separate steps of the conversion of ammonia to nitrite and of nitrite to nitrate. This directly led to the concept of the cycles of sulphur and nitrogen in nature. He was the first to isolate a free-living nitrogen-fixing bacterium. He formulated the concept of chemolithotrophy, the ability of bacteria to obtain energy by the oxidation of reduced inorganic compounds such as H2S, NH3, Fe2+. Winogradsky 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. Previously, it was believed that autotrophs obtained their energy solely from light, not from reactions of inorganic compounds. With the discovery of organisms that oxidized inorganic compounds such as hydrogen sulfide and ammonium as energy sources, autotrophs could be divided into two groups: photoautotrophs and chemoautotrophs. Winogradsky was one of the first researchers to attempt to understand microorganisms outside of the medical context, making him among the first students of microbial ecology and environmental microbiology. The Winogradsky column remains an important display of chemoautotrophy and microbial ecology. This is demonstrated even today in microbiology lectures around the world.History of Microbiology
