History of Microbiology .

Other important contributions to microbiology include:
Aristotle suggested the existence of microorganisms in the 4th century BC.
Roger Bacon suggested that invisible living creatures were the cause of diseases.
Girolamo Fracastoro gave the term syphilis to an outbreak in Europe in the 1400s.
Francesco Stelluti made the first microscopic observations of bees and weevils.

1. Amjad Khan Afridi Lecturer, Health & Biological Sciences, Abasyn University Peshawar A Brief History of Microbiology

2. The study of microorganisms. Microorganisms : Small living organisms that generally can not be seen with the naked eye. Include: Bacteria Fungi (yeasts and molds) Protozoa Algae Multicellular parasites Also include nonliving infectious agents: Viruses Prions Microbiology

3. Earth: Have many important and beneficial biological functions: Photosynthesis: Algae and some bacteria capture energy from sunlight and convert it to food, forming the basis of the food chain . Decomposers: Many microbes break down dead and decaying matter and recycle nutrients that can be used by other organisms. Nitrogen Fixation : Some bacteria can take nitrogen from air and incorporate it into soil. Microbes are Essential for Life on

4. Digestion: Animals have microorganisms in their digestive tract, that are essential for digestion, vitamin synthesis, and overall health. Cellulose digestion ( termites , cows, rabbits, etc.) Vitamin K and B synthesis in humans Prevent the overgrowth of pathogenic bacteria and yeast Medicine: Many antibiotics and other drugs are naturally synthesized by microbes. Penicillin is made by a mold Important and beneficial biological functions of Microbes

5. Penicillin is Produced by a Mold

6. Food Industry: Many important foods and beverages are made with microbes: Bread Vinegar Pickles, olives, sauerkraut Soy sauce Cheese Yogurt Buttermilk Sour cream Coffee Chocolate Hams, sausages I mportant and beneficial biological functions of Microbes

7. Genetic Engineering: Recent advances in gene splicing allow us to design recombinant microbes that produce important products: Human growth hormone (Dwarfism) Insulin (Diabetes) Blood clotting factor (Hemophilia) Recombinant vaccines Hepatitis A and B vaccines Human hemoglobin (Emergency blood substitute) Taxol, antimitotic  (Breast and ovarian cancer) Erythropoietin (Anemia) Monoclonal antibodies (Disease diagnosis and prevention). I mportant and beneficial biological functions of Microbes

8. Medical Research: Microbes are well suited for biological and medical research for several reasons: Relatively simple and small structures, easy to study. Genetic material is easily manipulated. Can grow a large number of cells very quickly and at low cost. Short generation times make them very useful to study genetic changes. I mportant and beneficial biological functions of Microbes

9. Most microbes are either beneficial or harmless to humans. Less than 1% of microbes cause disease. In 1962, the surgeon general of the United States stated: “The war against infectious diseases has been won”. Today it is clear that this was overly optimistic: Emerging diseases : New diseases like AIDS, hantavirus, Ebola fever, Lyme disease, Hepatitis C, and others that did not exist a few years ago. Antibiotic and Drug Resistance: Many old diseases are becoming resistant to traditional therapies: Tuberculosis, gonorrhea, malaria, etc. Today infectious diseases cause 50% of the 52 million worldwide deaths per year. Microbes and Disease

10. Infectious Diseases Causing Most Deaths Worldwide in 2000 Disease Cause Deaths/year Acute Respiratory * Bacterial or viral 4,400,000 Diarrheal diseases Bacterial or viral 3,200,000 Tuberculosis Bacterial 3,100,000 Malaria Protozoan 3,100,000 Hepatitis B Viral 2,000,000 Measles Viral 1,500,000 AIDS Viral 1,000,000 Neonatal Tetanus Bacterial 600,000 * : Pneumonia, bronchitis, influenza, etc.

11. History of Microbiology Physics began in ancient times, mathematics even earlier, but the knowledge of tiny living things, their biology, and their impact on human lives have only been around since the late 19th century . Until about the 1880s, people still believed that life could form out of thin air and that sickness was caused by sins or bad odors .

12. Discovery of Microbes and the Dawn of Microbiology Microbiology is the study of living organisms of microscopic size. The term microbiology was given by French chemist Louis Pasteur (1822-95). Microbiology is said to have its roots in the great expansion and development of the biological sciences that took place after 1850. The term microbe was first used by Charles Emmanuel Sédillot   (1878).

13. History of Microbiology Early Studies Before 17th century, study of microbiology was hampered by the lack of appropriate tools to observe microbes. Robert Hooke : English scientist In 1665 built a compound light microscope and used it to observe thin parts of cork. Coined the word cell .

14. History of Microbiology Early Studies Anton van Leeuwenhoek (1632-1723) Was Dutch amateur biologist  In 1673 was the first person to observe live microorganisms (bacteria and protozoa) which he called “ animalcules ” (little animals) , using single-lens microscopes that he designed (homemade microscopes). H e is known as the “ Father of microbiology ”. Leeuwenhoek is also considered to be the father of bacteriology and protozoology (protistology). He wrote over 200 letters which were transmitted as a series of letters from 1674-1723 to Royal Society in London during a 50 years period.

15. History of Microbiology Spontaneous Generation vs Biogenesis Before 1860s many scientists believed in Spontaneous generation , i.e.: That living organisms could arise spontaneously from nonliving matter: Mice come from rags in a basket. Maggots come from rotting meat. Ants come from honey. Microbes come from spoiled broth.

16. History of Microbiology Spontaneous Generation vs Biogenesis Theory of Biogenesis: Belief that living cells can only arise from other living cells. Francesco Redi : In 1668 proved that maggots do not arise spontaneously from decaying meat. Lazaro Spallanzani: In 1765 found that nutrient broth that had been heated in a sealed flask would not become contaminated with microbes. Some proponents of spontaneous generation argued that boiling had destroyed the “life force” of air in flask. Others argued that microbes were different from other life forms. 12 th , October, 2022

17. History of Microbiology Spontaneous Generation vs Biogenesis Debate was finally settled by Pasteur. Louis Pasteur : In 1861 finally disproved spontaneous generation when he demonstrated that microorganisms in the environment were responsible for microbial growth in nutrient broth. Designed swan neck flasks that allowed air in, but trapped microbes in neck. Developed aseptic technique : Practices that prevent contamination by unwanted microorganisms.

18. Pasteur’s Swan Neck Experiment

19. History: Pasteur’s Conclusions The bended neck allowed air to enter the bottle and the liquid but trapped any particulates including microorganisms. No microbial growth as long as the liquid broth did not come in contact with the microbes . Hence air alone was not sufficient to generate life.

20. Rapid advances led to the development of microbiology as a science. Pasteur’s Contributions to Microbiology: Fermentation : Pasteur found that yeasts were responsible for converting sugar into alcohol in the absence of air. Souring and spoilage were caused by bacterial contamination of beverages. History of Microbiology Golden Age: 1857-1914

21. Pasteur’s Contributions: Pasteurization: Developed a process in which liquids are heated (at 65 o C) to kill most bacteria responsible for spoilage. Disease Causes : Identified three different microbes that caused silkworm diseases. Vaccine: Developed a vaccine for rabies from dried spinal cords of infected rabbits. Directed Pasteur Institute until his death in 1895. History of Microbiology Golden Age: 1857-1914

22. Pasteur Institute, 1887

23. Germ Theory of Disease: Belief that microbes cause diseases. Before, most people believed diseases were caused by divine punishment, poisonous vapors, curses, witchcraft, etc. Agostino Bassi (1835): In between, 1808 and 1813, Found that a fungus was responsible for a silkworm disease. calcinaccio Ignaz Semmelweis (1840s): Demonstrated that childbirth fever was transmitted from one patient to another, by physicians who didn’t disinfect their hands. He was ostracized by colleagues. History of Microbiology Golden Age: 1857-1914

24. Germ Theory of Disease: Joseph Lister (1860): Used disinfectant to treat surgical wounds, greatly reducing infection rates. Considered the father of antiseptic surgery . Robert Koch (1876): First person to conclusively prove that a specific bacterium caused a disease. Germ Theory : One microbe causes one specific disease. Proved that Bacillus anthracis causes anthrax in cattle. Later identified bacterium that causes tuberculosis . History of Microbiology Golden Age: 1857-1914

25. Chemotherapy: Treatment of a disease by using a chemical substance. Chemical must be more poisonous to microbes than host. Quinine : First known chemical to treat a disease (malaria). Used by Spanish conquistadors. Synthetic Drugs: Made in the laboratory. Antibiotics: Produced naturally by fungi and bacteria. History of Microbiology Modern Microbiology: After 1914

26. Alexander Fleming (1928) : Discovered that penicillin produced by the mold Penicillium notatum was able to prevent microbial growth. Penicillin was not mass produced until the 1940s. Rene Dubos (1939): Discovered two antibiotics ( gramidin and tyrocidine) produced by bacterium ( Bacillus brevis ). History of Microbiology Modern Microbiology: After 1914

27. Problems with Chemotherapy: Toxicity Drug resistant microbes History of Microbiology Modern Microbiology: After 1914

28. Diversity of Microorganisms I. Bacteria (Sing. Bacterium) Small, single-celled ( unicellular ) organisms. Procaryotes: “Before nucleus”. Lack the following structures: Nuclear membrane around DNA Membrane bound organelles Mitochondria Chloroplasts Golgi apparatus Endoplasmic reticulum Lysosomes

29. Kingdom Prokaryotae: Bacteria lack nucleus and membrane bound organelles

30. Include two groups: Eubacteria : Peptidoglycan cell walls. Archaebacteria : Lack peptidoglycan cell walls. Shapes : Several forms: Bacilli : Rod like. (Sing. Bacillus) Cocci : Spherical. (Sing. Coccus) Spiral : Corkscrew or curved Square Star shaped Diversity of Microorganisms I. Bacteria (Sing. Bacterium)

31. Divide by binary fission (not mitosis). Source of nutrients varies: Heterotrophs : Consume organic chemicals. Autotrophs : Make their own food. Include photosynthetic bacteria. Motility : Many can “swim” by using moving appendages: Cilia: Small hair like structures Flagella: Large whip like structures. Distinguish between motility and Brownian motion . Diversity of Microorganisms I. Bacteria (Sing. Bacterium)

32. Eucaryotes: “True nucleus” DNA is surrounded by nuclear membrane . Cells have membrane bound organelles : Mitochondria, endoplasmic reticulum, etc. Cells are larger than those of procaryotes . May be unicellular or multicellular: Unicellular : Yeasts Multicellular : Molds, mushrooms Do not carry out photosynthesis. Must absorb organic nutrients from their environment. Diversity of Microorganisms II. Fungi (Sing. Fungus)

33. Source of nutrients varies: Saprotrophs : Decomposers that feed on dead and decaying matter. Most fungi are decomposers. Parasites : Obtain nourishment by parasitizing live animals and plants. Cell wall made of chitin. May reproduce sexually or asexually. Diversity of Microorganisms II. Fungi (Sing. Fungus)

34. Eucaryotes: “True nucleus” DNA is surrounded by nuclear membrane. Cells have membrane bound organelles and are larger than those of procaryotes. Unicellular Kingdom Protista Sexual or asexual reproduction Classified based on locomotion: Pseudopods : “False feet”. Cytoplasmic extensions. Example : Amoeba Diversity of Microorganisms III. Protozoa (Sing. Protozoan)

35. Protozoa Belong to Kingdom Protista: Eucaryotic Unicellular or Simple Multicellular Organisms

36. Classified based on locomotion: Flagella : Long whip like appendages. Example: Trichomonas vaginalis , causes trichominiasis , a sexually transmitted disease. Cilia : Small hair like appendages Non-motile : Do not move in their mature forms. Example: Plasmodium spp., causative agent of malaria. Diversity of Microorganisms III. Protozoa (Sing. Protozoan)

37. Eucaryotes: “True nucleus” Photosynthetic: Important part of food chain because produce oxygen and carbohydrates used by animals. Unicellular or multicellular Kingdom Protista Sexual or asexual reproduction Cell walls composed of cellulose Found in aquatic environments (oceans, lakes, rivers), soil, and in association with plants. Diversity of Microorganisms IV. Algae (Sing. Alga)

38. Acellular infectious agents, not considered living because they lack cells. Obligate intracellular parasites : Viruses can only reproduce by using the cellular machinery of other organisms. Simple structure : Protein coat ( capsid ) with either DNA or RNA, but not both. May also have a lipid envelope. Diversity of Microorganisms V. Viruses

39. Comparison of Cells and Viruses

40. Eucaryotes: “True nucleus” Multicellular animals , usually are visible to the naked eye. Microscopic during some stages of life cycle. Spend part or all of their lives inside an animal host. Helminths include: Flatworms (Platyhelminths): E.g. Tapeworm Roundworms (Nematodes): E.g. Ascaris, pinworm. Diversity of Microorganisms VI. Multicellular Animal Parasites

41. 18 th October, 2022 [email protected]