Lesson 1 & 2 (1) PDF

Lesson 1 Introduction Microbiology is a specialized branch of biology that deals with the study of organisms that are so small and cannot be seen with the naked eye. These microscopic organisms are also called mic...

Lesson 1 Introduction Microbiology is a specialized branch of biology that deals with the study of organisms that are so small and cannot be seen with the naked eye. These microscopic organisms are also called microorganisms or microbes. Some people call them as germs or bugs in reference to their role in infection and diseases. Microbiology includes the study of every aspect of the microbe—their genetics, physiology, characteristics that may lead to disease or to benefits, the way they interact with the environment, the way they interact with mammalian hosts, and their uses in industry and agriculture. Learning Outcomes: 1. Explain the history of microbiology. 2. Illustrate the microbial diversity. 3. Describe the general characteristics of bacteria, protozoans, fungi, helminths and viruses.  There are several major groups of microorganisms that will be studied--they are bacteria, protozoa, algae, fungi, helminths and viruses. They all have different biological characteristics that is a distinguishing trait/feature that can be used to describe or define an organism. Some Divisions of Microbiology: (1) Bacteriology, the study of bacteria; (2) Mycology, the study of fungi; (3) Phycology, the study of algae; (4) Parasitology, the study of parasites such as protozoa, helminths and arthropods; (5) Protozoology, the study of protozoa; (6) Virology, the study of viruses; (7) Immunology, studies on the complex web of immune chemicals and cells that are produced in response to infection. (8) Public Health Microbiology and Epidemiology aim to monitor and control the spread of diseases in communities. (9) Biotechnology a technology that utilizes biological systems, living organisms or parts of this to develop or create different products. (10) Agricultural microbiology is concerned with the relationship between microbes and crops, with an emphasis on improving yields and combating plant diseases. Roles of microorganisms: 1. A number of species of microorganisms inhabit the human body and are collectively referred to as normal flora (or indigenous flora/microbiota) and can be pathogenic (capable of causing diseases) or non-pathogenic. Some are useful for the human host, and majority have no known beneficial or harmful effects which may participate in maintaining health. 2. Some microorganisms are essential in biotechnology, e.g., in the production of foods and beverages. 3. Some microorganisms, especially bacteria and fungi, are sources of antibiotics. Examples of antibiotics (above). Source: https://www.channel3000.com/experts-say-9-in-10- people-who-believe-they-are- allergic-to-penicillin- are-not/ Products involving biotechnology (left). Source: https://tipsychickens.com/grapefruit-white-wine-spritzer-recipe/ 4. Some microbes are saprophytes (decomposers of waste products and dead organisms). 5. Microorganisms also play important roles in certain biogeochemical cycle (e.g., the nitrogen cycle) and in the breakdown of organic substance to release plant nutrients like nitrates and phosphates, which are sources of fertilizers. The study of the relationship between microorganisms and the environment is known as microbial ecology 6. Some microorganisms are used in the production of useful substances like insulin and interferon, through a process known as genetic engineering. 7. Some microorganisms and their products, such as toxins, are also potential biological warfare agents, example – Anthrax (Bacillus anthracis) Food for Thought! Friendly bacteria! Probiotics are live microorganisms that are similar to beneficial microorganisms found in the human intestine. They are also called “friendly”, or good bacteria. If you take an antibiotic, you may kill “good” as well as “bad” or pathogenic bacteria. Probiotics are available to consumers in the form of foods (yogurt) and dietary supplements. They can be used to replace or restore the “good bacteria” that were present in our intestines before antibiotic use. In people with suppressed immune systems, these products may even be dangerous because the organisms they contain may cause illness.  Lesson 2: History of Microbiology The story unfolds the history of events and phenomenon for which there was no understanding or explanation, followed by observations for which there was no obvious application, to the eventual association of cause and effect, onto a full-blown field of inquiry. Few noble pioneers have made the course of history by giving an impact in the field of Microbiology. There have been major improvements in the way we apply microorganisms in technology and to address environmental problems. Our science will need to continue to develop at a rapid rate as seen in the past decade. The Era of Superstitious Belief and Speculation (5000 BC to 1675) Medical practices in ancient times were heavily tinged with superstitious beliefs. They only assumed that there was a disease and may lead to death, but they have no knowledge of the cause of disease or deaths. Remedies to cure diseases were: burning incense, dripping handkerchiefs in aromatic oil, ringing church bells and firing cannons, wearing talismans (charms or magical figures), bathing in human urine, placing ‘stinks’ dead animal in their dwellings, bleeding via leeches and bloodletting, drinking liquid gold or powdered emeralds, and joining groups of flagellants. The concept of quarantine (meaning forty days) was already instituted where an infected individual be kept isolated from others. The Era of Observation (1675 to mid-19th century) The time where men started to be curious and created tools for investigation. By the end of the 16th century, lenses were available to magnify objects a hundred-fold, but cannot see bacteria. Robert Hooke (1665) discovered the cell, the basic unit of life. His discovery heralded The Cell Theory Anton van Leeuwenhoek (1676) Father of Microbiology First to observed microscopic organisms, which he called animalcules. He paved the way to microscopic world to scientists and was regarded as one of the first to provide accurate descriptions of protozoa, fungi, and bacteria.  Theory of spontaneous generation - states that “microorganisms arise from lifeless matter”. Examples: mice are being produced from dirty shirts and grains, dust creates fleas, frogs come from mud. Francesco Redi disputed the theory and showed that fly maggots do not arise from decaying meat as others believed. An English cleric named John Needham advanced spontaneous generation, but Lazzaro Spallanzani disputed the theory by showing that boiled broth would not give rise to microscopic forms of life; also found that new microorganisms could settle only in a broth if the broth was exposed to the air. In the 18th century the production of alcohol, vinegar, and beer started even without the knowledge of biochemical processes involved. Louis Pasteur (1859) disproved the spontaneous generation by his Swan-Neck Flask experiment. Germs in the air were able to go down the straight neck flask and contaminated the broth. The other flask trapped germs in the curved neck flask preventing them from reaching the broth which never changed color or became cloudy.  He was the first to report the role of microorganisms in fermentation process and unraveled the mystery of sour wine; developed the process of pasteurization, which kills microorganisms in different types of liquid; proposed the germ theory of disease but failed to relate a specific organism to a specific disease. John Tyndall provided the initial evidence that some of the microbes in dust and air have very high heat resistance, and that other microorganisms are easily killed by boiling. Robert Koch - ( Father of Bacteriology ) proved Pasteur’s germ theory. Established “Koch’s Postulates,” indicates that a certain organism is the cause of a specific disease. The first to prepare dried films of bacteria, stained, protected with coverslips and made permanent preparations. This technique made the first photomicrographs of bacteria. Edward Jenner (1800) discovered the vaccine for smallpox virus. Ferdinand Cohn (1849) discovered endospores (heat resistance form of bacteria) , and the first to stain histological sections usingvegetable dyes. Joseph Lister (1867) applied the Germ Theory to medical procedures, hence the start of aseptic (sterile) surgery. Hans Christian Gram (1884) discovered the Gram-staining procedure. In the mid-1880s, Elias Metchnikoff, a Russian born Jew advances his theory of the cellular basis of immunity. He set out to demonstrate that it was the white blood cells that protected us from invading microbes. Professor Claus, his colleague, coined the term phagocytes, from the Greek word for devouring cells. Era of Chemotherapy (Golden Age of Microbiology) – 19th Century Chemotherapy is the use of chemicals that selectively inhibit or kill pathogens without causing damage to the patient. Paul Erlich (1909) discovered salvaran, the “magic bullet” for the treatment of syphilis Alexander Fleming (1928) discovered the first “wonder drug,” penicillin (antibiotic), was a great success that can kill susceptible microorganisms and inhibit growth. Large scale production of penicillin was in great demand to save the lives of thousands of wounded soldiers during World War II. Max Knoll and Ernst Ruska (1931) at Berlin Technische Hochschule invented the electron microscope that overcame the barrier to higher resolution that had been imposed by the limitations. It can magnify objects 1,000,000 times.  It was the first time bacteria were seen as being cellular like all other microbes, plants and animals. Cultivation of viruses were introduced and knowledge of viruses developed rapidly By the 1940s, genes were understood as discrete units of heredity, which also generate the enzymes that control metabolic functions. But in 1944, experiments by Oswald T. Avery showed that a nucleic acid, deoxyribonucleic acid (DNA), known to be ubiquitous in organisms, was the chemical basis for specific and apparently heritable transformations inbacteria. 1950 – 1960 Development of vaccines of viral diseases such as polio, measles, mumps, and rubella. Human Immunodeficiency Virus (HIV) was discovered by Luc Montagnier and Robert Gallo acquired immunodeficiency syndrome (AIDS). Modern Microbiology (Biotechnology Period) By the 1970s, research on bacterial physiology, biochemistry and genetics had advanced to such an extent that it was possible to experimentally manipulate the genetic material of living organisms. With the invention of restriction enzymes, it became possible to introduce DNA from foreign sources into bacteria and control its replication. This led to the development of fascinating field of Biotechnology. In Biotechnology, microorganisms are used as living factories to produce pharmaceuticals that otherwise could not be manufactured, such as human hormone insulin, antiviral substance interferon, numerous blood‐clotting factors and clot dissolving enzymes, and a number of vaccines. Bacteria can be reengineered to increase plant resistance to insects and frost.