Introduction to General Microbiology PDF

Part I Introduction to General Microbiology  CHAPTER 1 The History and Scope of Microbiology  Microbiology is the study of microorganisms, a large, diverse group of microscopic organisms that exist as single cells or cell clusters; it also includes viruses, which a...

Part I Introduction to General Microbiology  CHAPTER 1 The History and Scope of Microbiology  Microbiology is the study of microorganisms, a large, diverse group of microscopic organisms that exist as single cells or cell clusters; it also includes viruses, which are microscopic but not cellular Microbial cells are thus distinct from the cells of animals and plants, which are unable to live alone in nature and can exist only as parts of multicellular organisms. Why study microbiology? Microbiology, one of the most important of the biological sciences, is studied for two major reasons: 1. As a basic biological science. 2. As an applied biological science. Microbiology deals with many important practical problems in medicine, agriculture, and industry. Microorganisms play major role in Soil fertility and animal production. Microorganisms cause some of the most importantdiseases of humans, animals and plants.  Within microbiology separate disciplines may be recognized including mycology, bacteriology, virology and protozoology for the study of fungi, bacteria, viruses and protozoa, respectively. It is closely related to several other disciplines, such as: 1. Parasitoloy: 2. Immunology: 3.Pathology: 4.Epidemiology: 5. Public health and hygiene: 6. Biotechnology:  Historical Perspectives of Microbiology A.HISTORICAL BACKGROUND OF MICROBIOLOGY 1.Humans made use of microbial products long before organisms were discovered. a. Food (mushrooms). b. Fermented beverages (beer and wine). c. Medicines that had antibacterial properties. d. Food preservation (salting and drying).  B. THE ADVENT OF THE MICROSCOPE 1. Anton van Leeuwenhoek (Netherlands) made his own microscopes and was the first to observe bacteria, yeasts, and protozoa. 3. Paul Ehrlich in 1881 introduced vital staining of bacteria with methylene blue. 4. Hans Christian Gram in 1884 introduced the differential staining method now named in his honor, the Gram stain  C. Pasteur and the Beginning of Food and Industrial Microbiology Before Pasteur: the argument about spontaneous generation (living organisms arising in decaying matter from no preexisting structure, such as an egg).  Louis Pasteur (The Father of Microbiology) a. In 1861 destroyed theory of spontaneous generation by using a swan-necked flask. After boiling a liquid, he was able to leave a vessel containing a fermentable substrate open to the air and show that fermentation did not occur.  D. Koch and the beginning of medical microbiology 1. The studies of Robert Koch greatly advanced the field of medical microbiology. 2. He showed that microorganisms grown outside the body could cause disease. 4. Alexander Fleming reported the antibacterial action of Penicillium cultures in 1929. He named the active ingredient penicillin. Classification of organisms kingdom classification system (Woese, 1980) 1) Kingdom of Archaebacteria (one-celled organisms that lack organelles) 2) Kingdom of Eubacteria (also one-celled organisms that lack organelles) 3) Kingdom of Eukaryotes (uni- or multi-cellular organisms with organelles) In another classification system both Archaebacteria and Eubacteria belong to a class Prokaryote, whereas Eukaryote is another class. Prokaryote: in that class the cell lacking a true nucleus structure (primitive nucleus). Eukaryote: in that class the cell possessing a membrane-enclosed nucleus (true nucleus) and usually other organelles.