2. History of Microbiology.pdf

Course: General Microbiology (BIOC 230) History of Microbiology - golden age Dr. Sunil Mundra...

Course: General Microbiology (BIOC 230) History of Microbiology - golden age Dr. Sunil Mundra Assistant Professor Department of Biology [email protected] UAE University, Al-ain Brief History of Microbiology Earth about 4.5 billion years old Ancestors of bacteria were the first life on Earth. ex. photosynthetic cynanobacteria (3.7 byo) Extremophiles: Photosynthetic fossilized The first microbes were observed in 1673. cyanobacteria in a billion year old rock formation of Glacier National Park, Montana, USA Stromatolites — like these, may contain cyanobacteria, which were most likely earth's first photosynthetic organisms and date back to about 3.7 billion years ago.  Brief History of Microbiology By end of 19th century, these organisms were called microbes Discoveries of Microscope Robert Hooke (1685) Englishman, used a primitive compound (two magnifying lenses) He was the first to observe cells while looking at tree bark and reported that living things were composed of little boxes (smallest units) that he called “cells.” Started the process of the development of the Cell theory of life Looked at cork under a microscope and coined the term “cells” Discoveries of Microscope Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723) He became very interested in lenses while working with magnifying glasses in a dry goods store. He used the magnifying glass to count threads in woven cloth. Leeuwenhoek known as Improved the simple microscope to a magnification of Father of Microscopy 270x Father of Protozoology and Bacteriology Described first microbes Discoveries of Microscope Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723) He became very interested in lenses while working with magnifying glasses in a dry goods store. He used the magnifying glass to count threads in woven cloth. By grinding and polishing, he was able to make small lenses with great curvatures. These rounder lenses produced greater magnification, and his microscopes were able to magnify up to 270x. He found that pure rain water contained live microorganisms (he called them animalcules) that he also observed in teeth scrapings. Leeuwenhoek known as He described what we know today as bacteria – rod shaped , Father of Microscopy spiral shaped , etc. “animalcules” Father of Protozoology and Bacteriology Discoveries of Microscope Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723) He described what we know today as bacteria – rod shaped , spiral shaped , etc. “animalcules” Discoveries of Microorganisms Earliest microscopic observations. Francesco Stelluti: observed bees and weevils between 1625 to 1630. Robert Hooke: published drawings of the fungus Mucor in his book, Micrographia, in 1665. Antony van Leeuwenhoek (1632 to 1723): First person to observe microorganisms accurately. Discoveries of Microorganisms Scientists searched for answers to four questions Is spontaneous generation of microbial life possible? What causes fermentation? What causes disease? How can we prevent infection and disease? Prior to the 1800s, disease was attributed to various factors such as evil spirits, sin, imbalances in body fluids, and foul vapors. Aristotle (384 B.C.) - Spontaneous generation Older belief: Diseases were caused only by God He thought that the mice grew from the grain and hay, and he coined the term “Spontaneous generation”, the hypothesis that living organisms arise from nonliving matter. Published a recipe to grow their own mice: darkness + hay + grain = mice. Virgil (40 A. D.): Agreed with Aristotle and proposed that that bees grew from honey that flies grew from meat. Again, this was accepted for centuries. The conflict over spontaneous generation Spontaneous generation (Aristotle). Idea that living organisms can develop from nonliving or decomposing matter. Francesco Redi (1626 to 1697). Discredited spontaneous generation. Showed that maggots on decaying meat came from fly eggs. John Needham (1713 to 1781). His experiment: mutton broth in flasks → boiled →sealed. Results: broth became cloudy and contained microorganisms. Lazzaro Spallanzani (1729 to 1799). His experiment: water and seeds in flasks → sealed → boiled. Results: no growth of microorganisms. Louis Pasteur (1822 to 1895) Swan neck flask experiment. The conflict over spontaneous generation Francesco Redi – 1668 – opposed the prevailing theory of Spontaneous Generation Maggots in meat: He used covered jars to show that maggots came from flies – strong evidence against spontaneous generation Theory of Biogenesis – Biogenesis is the hypothesis that living organisms arise from pre-existing life. “All living beings come from seeds of the plants or animals themselves” The conflict over spontaneous generation Louis Pasteur (1822 to 1895) ‘Swan-neck flask’ experiments. Placed nutrient solution in flasks. Created flasks with long, curved necks. Boiled the solutions. Left flasks exposed to air. Results: no growth of microorganisms. Role of microorganisms in disease Was not immediately obvious. Infectious disease believed to be due to supernatural forces or imbalances of 4 bodily-fluid ‘humors’. Establishing connection depended on. development of techniques for studying microbes Edward Jenner (ca. 1798) Developed the first Vaccine and used a vaccination procedure to protect individuals from smallpox Oliver Holmes (1773 - 1843) Showed that sepsis could be transmitted by hands of medical student and may cause disease M. J. Berkeley (ca. 1845) Great Potato Blight of Ireland was caused by a Fungus Louis Pasteur (1822 - 1895) Developed other vaccines including those for chicken cholera, anthrax, and rabies  Edward Jenner Vaccination Edward Jenner (ca. 1798) - Father of immunology Inoculated a person with cowpox virus. The person was then protected from smallpox and the protection is called immunity. “vacca” latin meaning cow. Vaccination: Inoculation of healthy individuals with weakened (or attenuated) forms of microorganisms, that would otherwise cause disease, to provide protection, or active immunity from disease upon later exposure. Vaccination: Smallpox Caused by the virus Variola major and Variola minor Deadly disease with 30-35% mortality rate Survivors often suffer from disfigurement and blindness. Caused million deaths in the 20th century WHO managed to eradicate smallpox in 1979 Notable victims include: Queen Mary II of England Emperor Joseph I of Austria King Luis I of Spain King Louis XV of France Vaccination: Chicken cholera Pasteur worked on ways to prevent chicken cholera Due to neglect of his assistant, old culture were used to inoculate chickens. Chickens recovered and became immune Bacteria had become weakened (attenuated) Artificially weakened infectious disease = “vaccines” Produced the first attenuated vaccine for rabies by drying the nerve tissue of infected rabbits Vaccination: Rabies In 1885, a young boy, Joseph Meister, had been bitten by a rabid dog, and was brought to Pasteur. The boy almost certainly would have died an agonizing death if nothing was done. So Pasteur took the risk on using his untested vaccine. The first injection was made in a fold of skin covering the boy’s right upper abdomen. Over a period of three weeks, Joseph was given 13 such inoculations. Pasteur monitored the virulence of each dose by first injecting them in healthy rabbits to insure the vaccine did not cause rabies. Each dose came from progressively more rabid rabbits. At the end of the treatment course, Joseph was inoculated with an especially virulent rabies virus from a mad dog. Nothing happened! Pasteur was pleased to announce, thanks to his vaccine, Meister had developed an immunity to rabies virus. Koch’s postulates Robert Koch (1843:1910) – Father of Modern bacteriology Using criteria developed by his teacher, Jacob Henle (1809-1895), established the relationship between Bacillus anthracis and anthrax. Koch’s Postulates: “There is a link between a particular microorganism and a particular disease”. Identified the causative agents for cholera, anthrax, and tuberculosis and proved the concept of infectious disease He also improved laboratory techniques and introduced bacterial agar and the petri dishes to purify the colonies Koch’s postulates and tuberculosis Postulate Experimentation 1. The microorganism must be Koch developed a staining present in every case of the technique to examine human tissue. disease but absent from M. tuberculosis could be identified in healthy organisms. diseased tissue. 2. The suspected Koch grew M. tuberculosis in pure microorganisms must be culture on coagulated blood serum. isolated and grown in a pure culture. 3. The same disease must Koch injected cells from the pure result when the isolated culture of M. tuberculosis into microorganism is inoculated guinea pigs. The guinea pigs into a healthy host. subsequently died of tuberculosis. 4. The same microorganisms Koch isolated M. tuberculosis in must be isolated again from pure culture on coagulated blood the diseased host. serum from the dead guinea pigs. Notable scientist of the “Golden age of Microbiology” Notable scientist of the “Golden age of Microbiology” Pasteurization and fermentation Pasteur showed that microbes are responsible for fermentation. Fermentation is the conversation of sugar to alcohol to make beer and wine. Microbial growth is also responsible for spoilage of food. Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar (acetic acid). Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. This application of a high heat for a short time is called Pasteurization, an industrial application widely used today. Antiseptic surgery Joseph Lister - Father of modern surgery Gangrene or wound rotting was a major problem associated with surgery After hearing about Pasteur – promoted sterile surgery Used carbolic acid (Phenol) to clean wounds and sterile surgical instruments Development of culture techniques Why? To enable the isolation of pure cultures (only one type of organism) Especially important during Koch’s period Gelatin not useful as solidifying agent (melts at >28 ºC and some bacteria hydrolyze it with enzymes) Fannie Hesse, the wife of one of Koch’s assistants, proposed using agar Not digested by most bacteria Melts at 100 ºC Used today - ~2% in solid media Richard Petri, another of Koch’s assistants, developed the Petri dish Development of culture techniques In 1884, Danish scientist Christian Gram (1853–1938) developed a staining technique involving application of a series of dyes that leave some microbes purple and others pink. The Gram stain is still the most widely used staining technique; it distinguishes Gram-positive from Gram-negative bacteria and reflects differences in composition of the bacterial cell wall Development in the field of Microbial Ecology Sergei Winogradsky (1856 to 1953) and Martinus Beijerinck (1851 to 1931). Studied soil microorganisms and discovered numerous interesting metabolic processes (for example, nitrogen fixation). Pioneered the use of enrichment cultures and selective media. The Birth of Modern Chemotherapy Treatment with chemicals is chemotherapy. Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics. Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes. Quinine from tree bark was long used to treat malaria. 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis. 1930s: Sulfonamides were synthesized. The birth of modern chemotherapy Alexander Fleming - Scottish physician and bacteriologist - 1928 Observed that colonies of bacterium Staphylococcus aureus disappeared where mold was growing Mold was later found to be a Penicillium species and the naturally secreted chemical was called penicillin, an antibiotic Antibiotics are natural agents Synthetic drugs are chemicals produced in labs (sulfas) Problems with them - toxicity, resistance, allergic reactions Fleming’s work - shelved until early WWII, sulfas were failing, needed penicillin to cure battle field wounds Now have thousands of antibiotics and synthetics (significant problem – emerging resistance) The birth of modern chemotherapy Florey, Chain and large team Continued research on penicillin at school of pathology in Oxford Managed to find a process for mass production Proposed correct chemical structure The birth of modern microbiology Watson and Crick (1953) – DNA structure Discovered the structure of the DNA molecule in 1953. Watson and Crick were awarded the 1962 Nobel Prize award. Their work became the basis for the Human Genome Project, which was a world-wide effort to list all of the sequences of nucleic acids in human DNA. This knowledge is helping to understand genetic disorders. This also opened up the field of Molecular Genetics, understanding how genes work at a molecular level. The birth of modern microbiology Jacob and Monod (1965) 1965 Did research on RNA and protein synthesis in bacteria – last Necessary step in understanding how genetics works on a cellular level (Replication, Transcription, Translation – protein synthesis – expression of traits) The birth of modern microbiology Led to a second golden age of microbiology (rapid expansion of knowledge). Discoveries. Restriction endonucleases (Arber and Smith). First novel recombinant molecule (Jackson, Symons, Berg). DNA sequencing methods (Woese, Sanger). Next Generation Sequencing Methods Bioinformatics and genomic sequencing and analysis Crisper-Cas9 tools for genome editing Major fields in Microbiology Medical microbiology—diseases of humans and animals. Public health microbiology—control and spread of communicable diseases. Immunology—how the immune system protects a host from pathogens. Microbial ecology is concerned with the relationship of organisms with their environment. Agricultural microbiology is concerned with the impact of microorganisms on food production. Food microbiology—microbes used to make food and beverages as well as spoilage microbes. Major fields in Microbiology Industrial microbiology. Penicillin and other antibiotics. Vaccines, steroids, alcohols and other solvents, vitamins, amino acids, enzymes, and biofuels. Microbial physiology studies metabolic pathways of microorganisms. Microbial genomics: Microbial genetics, molecular biology, and bioinformatics study the nature of genetic information and how it regulates the development and function of cells and organisms. Microbes are a model system of genomics. Take home message Microbiology is a field with a long history. The field continues to provide insights and a greater understanding of the world we can’t see with our eyes— even today. Microbiology, with all its aspects and assets, will continue to lead to new and useful scientific discoveries well into the future. Important Events in Microbiology (1665 to 1911) Important Events in Microbiology (1900 to 2010)