MCB 102 Introductory Microbiology PDF

MCB 102 INTRODUCTORY MICROBIOLOGY Dr. Shehu Idris Department of Microbiology Faculty of Pure and Applied Sciences Kaduna State University [email protected]  COURSE OUTLINES  MODULE 1  Introductio...

MCB 102 INTRODUCTORY MICROBIOLOGY Dr. Shehu Idris Department of Microbiology Faculty of Pure and Applied Sciences Kaduna State University [email protected]  COURSE OUTLINES  MODULE 1  Introduction  Definition and Scope of Microbiology  Classification of Microorganisms  MODULE 2  History of Microbiology  Branches of Microbiology  MODULE 3  Importance of Microorganisms to Human Life  Microbes as Foes and Friends  MODULE 4  Basic Techniques for the Study of Microorganisms  COURSE OUTLINES cont.  MODULE 5  Concept of Aseptic Techniques  Sterilization  Disinfection  MODULE 6  Microbial Cell Structure and Function  MODULE 7  Concept of Microbial growth  INTRODUCTION cont. ▪ MCB 102, Introductory Microbiology is a foundation course for undergraduate students of microbiology ▪ It is designed to expose students to the basic knowledge that will help them understand both the basic and applied aspects of microbiology ▪ The theory part of the course will be taught in class lectures. Practicals will also be conducted to complement the theory and equip the students with the skills of handling basic apparatus and methods used to study microbes. ▪ Assessment will be based on C.A (written test/quizzes, lecture attendance, practical reports) and the semester examination. The C.A will constitute 40% while the exams will constitute the remaining 60% ▪ The term Micro means very small i.e anything so small that it must be viewed with a microscope. ▪ Therefore, microbiology is the study of very small living organisms called microorganisms or microbes. ▪ Microorganisms are typically too small to be seen with the naked eye. ▪ Microbes are ubiquitous, meaning they are virtually everywhere. ▪ Only a small percentage of known microbes cause disease. ▪ Those that cause diseases are called pathogens and the diseases they cause are referred to as infectious diseases and microbial intoxications. ▪ Microorganisms that do not cause disease are called nonpathogens. ▪ The study of microbes is quite interesting because, microbes impacts our daily lives in a variety of ways. ▪ Microorganisms live on us and in us ▪ They are necessary in many industries ▪ They are essential for the cycling and recycling of elements such as carbon, oxygen, and nitrogen ▪ They are used to clean up toxic wastes ▪ They are used in genetic engineering and gene therapy ▪ They cause disease. E.g: ▪ Cholera caused by Vibrio cholerae, ▪ Tuberculosis caused by Mycobacterium tuberculosis, ▪ Typhoid fever caused by Salmonella typhi ▪ Bacillary dysentery caused by Escherichia coli, ▪ Anthrax caused by Bacillus anthracis, ▪ Malaria cause by Plasmodium falciparum, ▪ Candidiasis caused by Candida albican etc  CLASSIFICATION OF MICROORGANISM Microorganisms are basically classified into the following: Bacteria The study of bacteria is called Bacteriology. Example of Bactria include: Staphylococcus aureus. E. coli, Clostridium tetani etc Fungi The study of fungi is called mycology Example of fungi include: Penicillium sp. Aspergillus sp. Candida sp. Saccharomyces sp. etc Protozoa The study of protozoans is called Protozoology Protozoa Examples of protozoa include: Entamoeba sp., Plasmodium sp., Giardia sp. The study algae is called phycology Algae Examples of protozoa include: Entamoeba sp., Plasmodium sp., Giardia sp. VIRUSES The study of Viruses is called Virology. Example of Bactria include: Polio virus, HIV Virus, Rabies Virus e.t.c Notes: ❑ Most scientists however do not consider viruses to be living organisms, because they do not have a defined cell structure (acellular) and are obligate parasites. and are often referred to as “infectious particles,” rather than microorganisms.  Archaea are procaryotes that are distinguished from bacteria by many features, most notably:  Their unique ribosomal RNA sequences.  They also lack peptidoglycan in their cell walls  They have unique membrane lipids.  Some have unusual metabolic characteristics, such as the methanogens, which generate methane gas.  Many archaea are found in extreme environments.  Pathogenic archaea have not yet been identified  History of Microbiology  Among the most significant events in the early history of microbiology were the development of microscopes, bacterial staining procedures, techniques that enabled microorganisms to be cultured in the laboratory; and steps that could be taken to prove that specific microorganisms were responsible for specific infectious diseases.  Over the past 400 years, many individuals contributed to our present understanding of microorganisms.  Antony van Leeuwenhoek (1632–1723) was the first person to see live bacteria and protozoa, he is sometimes referred to as the “Father of Microbiology,”. As a hobby, he ground tiny glass to produce lenses, which he mounted in small metal frames, thus creating what today are known as single-lens microscopes or simple microscopes.  During his lifetime, Leeuwenhoek made more than 500 of these microscopes. His art of grinding lenses magnifies an object to 200–300 times its original size. In one of the hundreds of letters that he sent to the Royal Society of London; he wrote:  “My method for seeing the very smallest animalcules I do not impart to others; nor how to see very many animalcules at one time. This I keep for myself alone”.  Leeuwenhoek recorded his observations in the form of letters, which he sent to the Royal Society of London. His findings finally convinced scientists of the late 17th century of the existence of microorganisms.  However, Leeuwenhoek never speculated on the origin of these microbes, nor did he associate them with the cause of disease. Such relationships were not established until the work of Louis Pasteur and Robert Koch in the late 19th century.  Once scientists became convinced of the existence of tiny creatures that could not be observed with the naked eye, they began to speculate on their origin. On the basis of observation, many of the scientists of that time believed that life could develop spontaneously from inanimate substances, such as decaying corpses, soil and swamp grasses.  The idea that life can arise spontaneously from non-living material is called the theory of spontaneous generation or abiogenesis.  For more than two centuries, from 1650 to 1850, this theory was debated and tested. Following the work of others, Louis Pasteur and John Tyndall finally disproved the theory of spontaneous generation and proved that life can only arise from preexisting life. This is called the theory of biogenesis. The science of microbiology later achieved significant milestones due to the contribution of Louis Pasteur (1822-1895) and Robert Koch (1843–1910). Some contributions of Louis Pasteur to the development of Microbiology 1. Disprove the theory of abiogenesis 2. Explain the role of microorganisms in fermentation 3. Develop the process of pasteurization 4. Develop many vaccines against common bacterial infections 5. Contributed to the understanding of the germ theory of diseases (specific microorganisms cause specific infectious diseases). For example, anthrax is caused by a specific bacterium (Bacillus antracis) 6. Discovered the causative agent of silkworm diseases.  Some contributions of Robert Koch to the development of Microbiology 1. Contributed to the germ theory of diseases and developed steps that guide the diagnosis of infectious diseases (Koch’s pastulates) 2. Discovered the causative agent of anthrax (Bacillus anthracis) 3. Developed methods of bacterial fixation and staining 4. Developed solid media cultivation of bacteria which enable microbiologist to obtain and pure culture (a condition where only one type of organism is growing on a solid culture medium or in a liquid culture medium in the laboratory) 5. Discovered the causative agents of tuberculosis (Mycobacterium tuberculosis) and cholera (Vibrio cholerae).  Koch’s Postulates  1. A particular microorganism must be found in all cases of the disease and must not be present in healthy animals or humans.  2. The microorganism must be isolated from the diseased animal or human and grown in pure culture in the laboratory.  3. The same disease must be produced when microorganisms from the pure cultures are inoculated into healthy susceptible laboratory animals.  4. The same microorganism must be recovered from the experimentally infected animals and grown again in pure culture.  Importance of Microbes to Human Life and other Higher animals 1. Microorganisms contribute oxygen to our atmosphere 2. Many microorganisms help to cleanup our environment because some are involved in the decomposition of dead organisms and the waste products of living organisms. Collectively, they are referred to as decomposers or saprophytes. 3. Microorganisms help in making nutrient available to soil because many of them are involved in biogeochemical cycles of elements there 4. Some microbes serve as sources of foods e.g single cell protein. 5. Some beneficial microbes aid digestion as in the case of some protozoans in the GIT of termites 6. Many microorganisms are essential in the production of various food and beverages 7. Certain bacteria and fungi produce antibiotics that are used to treat patients with infectious diseases. By definition, an antibiotic is a substance produced by a microorganism that is effective in killing or inhibiting the growth of other microorganisms. 8. Microbes are essential in the field of genetic engineering where they are used to produce useful product such as insulin 9. Some microbes cause diseases (infectious diseases & intoxication).  Branches of Microbiology  Microbiology can be grouped into sub-disciplines, each of which could provide a carrier opportunity those who specializes in it. These sub-disciplines or branches of microbiology include: 1. Medical and Clinical Microbiology 2. Agricultural Microbiology 3. Environmental Microbiology 4. Microbial Genetics and Genetic Engineering 5. Microbial Physiology 6. Veterinary Microbiology 7. Industrial microbiology 8. Pharmaceutical microbiology 9. Epidemiology and Public Health Microbiology See you next week