MICROBIOLOGY Study Guide - 2012

CHAPTER 1. A BRIEF HISTORY OF THE DEVELOPMENT OF MICROBIOLOGY

The first person to observe microorganisms was the Dutch draper Antonie van Leeuwenhoek (1632–1723), who discovered Bacteria and Protozoa in 1676. He manufactured lenses that provided a 200–270-fold magnification, using them to examine microorganisms in A wide variety of samples, including pond Water, dental plaque, saliva, Blood, and many others. Everywhere he looked, Leeuwenhoek discovered tiny creatures that he called "animalcules" (little animals), leading him to conclude that the surrounding world is densely populated by microscopic inhabitants. In his book The Secrets of Nature Discovered by A. van Leeuwenhoek (1695), he not only described but also sketched many microorganisms. For a long time, the science of microbes remained purely descriptive. This foundational era of microbiology is known as THE MORphological PERIOD.

Despite the DISCOVERY OF MICROORGANISMS, questions regarding their role in human diseases remained unclear, requiring direct evidence. Such evidence was ultimately provided by the Russian physician and epidemiologist Daniil Samoilovich (1744–1805), who inoculated himself with fluid from the bubo of a plague patient and subsequently fell ill. Fortunately, he survived.

The 1830s marked the beginning of an era of intensive microscopic research. In 1827, the French chemist Jean-Baptiste Dumas (often noted as J. B. Desmazières) described The Structure of Yeasts forming a film On the surface of beer. A decade later, in 1837, the German scientist Friedrich Kützing (1807–1893), while investigating The conversion of alcohol into vinegar, drew attention to the slimy film forming on the liquid's surface. He established that it consists of microscopic living organisms directly involved in the accumulation of acetic acid in the medium.

The rapid development of microbiology in the 19th century led to the discovery of numerous infectious diseases, including anthrax, plague, tetanus, diphtheria, dysentery, cholera, and tuberculosis.

The foundations of modern microbiology were laid by the outstanding French scientist Louis Pasteur (1822–1895). Pasteur was the first to demonstrate that microorganisms are active forms of life—whether beneficial or harmful—that interact with the surrounding environment, including humans. He discovered the existence of "life without oxygen" and introduced the terms "aerobic" and "anaerobic." Pasteur proved that Fermentation (such as lactic acid and Alcoholic Fermentation) is not merely a chemical process, but a biological one driven by specific microorganisms. Many of Pasteur's discoveries brought immense practical benefits to humanity. While studying diseases affecting wine and beer, he determined that they are caused by microorganisms. To prevent spoilage, he proposed heating the beverages—a process now known as pasteurization.

In The Study of infectious diseases (such as anthrax, fowl cholera, and rabies), Pasteur not only elucidated their Etiology but also found ways to combat them. In 1879, while working with the CAUSATIVE AGENT OF fowl cholera, Pasteur discovered that under certain conditions, the virulence of pathogenic microorganisms diminishes. Building on these observations, Vaccines were developed, and by 1885 Pasteur introduced the rabies vaccination. His groundbreaking work ushered in a new era in The Development of microbiology: the physiological period.

The discoveries of the German scientist Robert Koch (1843–1910) were of paramount importance to medical microbiology. He began his research by studying the anthrax bacillus in 1877. Subsequently, in 1882, he announced the Discovery of the tuberculosis pathogen, which was named "Koch's bacillus" in his honor, earning him the Nobel Prize in 1905. Koch is also credited with discovering the cholera vibrio in 1883. To definitively link a specific microbe to a contagious disease, Koch proposed a methodology later known as Koch's postulates (or the Henle–Koch postulates). The core principles are as follows:

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 a pure culture on an artificial nutrient medium;

3) the cultured microorganism should cause disease when introduced into a healthy experimental animal.

He was the first to introduce solid nutrient media into microbiological practice for cultivating microorganisms. The Use of solid media made it possible to discover previously unknown species of microorganisms and isolate them into so-called pure cultures.

The pioneer of Russian microbiology was Lev Tsenkovsky (1822–1887). The primary subjects of his research were microscopic protozoa, Algae, and Fungi. Tsenkovsky developed his own version of a vaccine strain for the anthrax pathogen (known as Tsenkovsky's vaccine), which is still used today for the Prevention of this disease in animals.

Internationally renowned are the works of Ilya Mechnikov (1845–1916), who developed the phagocytic theory of Immunity in 1883. In 1909, Mechnikov was awarded the Nobel Prize for his research on phagocytosis. The scientist was also deeply interested in life extension. Mechnikov believed that human lifespan should naturally reach 100–120 years. He attributed premature Aging to the chronic self-poisoning of the organism by metabolic products of putrefactive bacteria inhabiting the Large Intestine. To suppress their growth, he recommended consuming foods containing lactic acid bacteria, which accumulate lactic acid and thereby lower intestinal pH.

A close associate of Ilya Mechnikov was Nikolai Gamaleya (1859–1949), who investigated numerous problems in medical microbiology. Together with Mechnikov, he established the first rabies vaccination station in Russia in Odessa in 1886 (making it the second such station in the world after Pasteur's in Paris).

Another prominent scientist who made immense contributions to the microbiology of infectious diseases was Daniil Zabolotny (1866–1920), widely regarded as a founding father of Epidemiology. Wherever epidemics broke out across the globe, Zabolotny was invariably on the front lines to help contain them. Through his studies of plague outbreaks, Zabolotny obtained scientific proof confirming the hypothesis of the natural reservoir of this disease and the critical role of wild rodents in maintaining the pathogen in nature.

The ESTABLISHMENT OF THE ecology of soil microorganisms is closely linked to the Russian scientist Sergei Winogradsky (1856–1953). He discovered The process of nitrification and demonstrated the existence of microbes capable of assimilating carbon dioxide—a process he termed METABOLISM/21.html">Chemosynthesis. Using ingenious microbiological techniques, Winogradsky isolated nitrogen-fixing microorganisms from the soil. He named one of them Clostridium pasteurianum in honor of Louis Pasteur. Furthermore, he pioneered the use of elective (enrichment) culture media to selectively cultivate specific groups of microorganisms.

Vasily Omeliansky (1867–1928), a student of Sergei Winogradsky, discovered anaerobic Cellulose-degrading bacteria as well as methane-producing bacteria. He authored the textbook Fundamentals of Microbiology, which was first published in Russia in 1909 and went through ten editions.

The late 19th century was marked by yet another breakthrough in microbiology. The Russian scientist Dmitry Ivanovsky (1864–1920) discovered the existence of Viruses—subcellular entities far smaller than bacteria and invisible under a Light Microscope.

Academician Nikolai Ierusalimsky (1901–1967) entered history as a classical figure in the Development of the theory of continuous microbial cultivation. His primary research focused on the physiology and biochemistry of MICROORGANISMS AND THE regularities of their growth, laying the scientific groundwork for the microbiological industry.

Other Russian scientists who made major contributions to the development of microbiology include Sergei Korolev (1874–1932), who laid the foundations of dairy microbiology; and Arseny Voitkevych (1876–1950), who demonstrated the therapeutic and prophylactic value of acidophilic rods. Significant contributions to the microbiology of milk and dairy products were also made by Alexandra Skorodumova, Vladimir Bogdanov, Nina Koroleva, and Lyudmila Bannikova. A vast contribution to general, industrial, and agricultural microbiology was made by

Vladimir Shaposhnikov (1884–1968), who published the first textbook on industrial microbiology; Nikolai Krasilnikov (1896–1973); and Nikolai Mishustin (1901–1991).

The advances in microbiology during the 20th century led to its specialization and The Emergence of new scientific disciplines, including virology, mycology, microbial genetics, and biotechnology. Distinct applied branches also formed according to their specific objectives, such as medical, industrial, agricultural, and veterinary microbiology.