Microbiology Lecture 1 - Introduction PDF

General Microbiology and Immunology Lecture 1: Introduction Dr/ Shimaa Mohamed Ali Sphinx University What is Microbiology? ‫علم دراسه الكائنات الدقيقه‬ It is the study of microorganisms. Micro bio ology too small to be seen...

General Microbiology and Immunology Lecture 1: Introduction Dr/ Shimaa Mohamed Ali Sphinx University What is Microbiology? ‫علم دراسه الكائنات الدقيقه‬ It is the study of microorganisms. Micro bio ology too small to be seen life study of with the naked eye What are Microorganisms? They are organisms that are too small to be visible by the naked eye.  Microorganisms: Microorganisms include bacteria, fungi, viruses, algae and protozoa. Microorganisms are everywhere; almost every natural surface is colonized by microbes. Some microorganisms can live hot springs, and others in frozen sea ice. Most microorganisms are harmless to humans; Less than 0.01% of bacteria cause disease. They sometimes cause diseases in man, animals and plants. They are involved in food spoilage. Microbes are essential for balance of nature (ecosystem); they decompose dead animals and plants and make cycles of carbon, oxygen, nitrogen and sulfur. In fact, we are dependent on microbes to help us digest our food. Until late 1800's, no one had proved that infectious diseases were caused by specific microbes. Why should I study Microbiology? 1.Impact on Human Health. Microbes and Human Although many microorganisms are beneficial, many others are the cause of infectious diseases (hazard effect). Microbes normally present in and on the human body are called normal microbiota. Normal microbiota prevent growth of pathogens Competitive inhibition. Produce growth factors such as folic acid and vitamin K. 2.Balance of Nature ( ecosystem balance): Play a role in decomposition. Decomposer is an organism that decomposes, or breaks down, organic material such as the remains of dead organisms. Decomposers include bacteria and fungi 3.Environmental : Provide safe drinking water; development of biodegradable products; use bacteria to clean up oil spills, etc. This called bioremediation????. 4.Industrial : Antibiotics, insulin, genetic engineering. Microbes catalyst production various food products: – cheese, pickles, green olives – yogurt, soy sauce, vinegar, bread – beer, wine 5.Agricultural ( plant microbiome): Research has led to healthier livestock and disease-free crops.  Branches of Microbiology ❑By Taxonomy Bacteriology: study of bacteria. Virology: study of viruses. Mycology: study of fungi. Protozoology: study of protozoa, single- celled organisms like amoebae. Phycology: study of algae. Immunology: study of the immune system and mechanisms involved in body immune responses against foreign bodies including pathogens.  Branches of Microbiology ❑By Type of Research Medical microbiology: study of causative agents of human diseases. Pharmaceutical microbiology: study of microorganisms responsible for production of antibiotics, enzymes, vitamins, vaccines and pharmaceutical substances. Food microbiology: study of microorganisms that spoil food or cause foodborne diseases and microorganisms used in food production. Agricultural microbiology: the study of microorganisms that affect crops production, soil fertilization and others that cause plant diseases. Aquatic microbiology: study of microorganisms and their activities in aquatic environment including fresh and marine water. Microbial biotechnology: using microbes to perform various tasks beneficial to human health, industrial and the environment. ❑Nomenclature of Microorganisms: Carolus Linnaeus “father” of modern taxonomy” established a system for scientific nomenclature in 1735. Each organism has two names (Binomial nomenclature): (Genus + species). italicized (or underlined). Genus: capitalized, “latinized”, used worldwide. The genus designation can be replaced with an initial. For example, the bacterium Staphylococcus aureus (S. aureus). All eukaryotes and prokaryotes are named this way. Viruses are not! ❑Nomenclature of Microorganisms: ▪ Escherichia coli (E. coli): Discovered by Theodor Escherich coli: live in the colon. ▪ Staphylococcus aureus (S. aureus): Staphylo: clustered arrangement of the cells; coccus: spherical in shape aureus: golden colour of many colonies.  Two Types of Cells 1. Prokaryotic (before nucleus) Cells, but with no internal membrane bound structures. Includes the bacteria. Also include 2 groups, the Chlamydia and the Rickettsiae, which differ from bacteria only in being somewhat smaller (0.2-0.5 µm in diameter) and in being obligate intracellular parasites. 2. Eukaryotic (true nucleus) Have internal membrane bound structures (membrane bound nucleus and membrane-bound organelles). Includes fungi, algae, protozoans, animals, plants.  Bacteria Prokaryotes About one-tenth the size of eukaryotic cells, typically 0.5–5.0 µm long. Peptidoglycan cell walls. Reproduce by binary fission. Utilize organic/inorganic chemicals, or photosynthesize to obtain energy. Motile or non-motile Many cause disease.  Bacteria Estimated 40 million bacterial cells in 1 gram of soil, 1 million in 1 ml fresh water. Approximately ten times as many bacterial cells in the human microbiota as there are human cells in the body, most in the gut flora, and many on the skin. Most common fatal bacterial diseases are respiratory infections, eg tuberculosis kills about 2 million people per year, mostly in sub-Saharan Africa. Less than 1% of microorganisms cause disease. ❑Normal microbiota: Synoname : normal flora They are microorganisms that found on the surface and deep layers of skin, in the saliva and oral mucosa, in the conjunctiva, and in the gastrointestinal tracts of every human being. These microbiota are not harmful to humans; some are even beneficial and most help maintain our health. ❑Pathogens: ‫المسبب مرض‬ A pathogen is any organism or agent that can produce disease. It can be a virus, bacterium, fungus, or parasite. Pathogens are biological agent that possess the ability to cause disease by invading and replicating within the host organism. 1. Opportunistic pathogens. 2. Strict pathogens. ❑Opportunistic pathogens: ❑ Strict pathogens Most of infections are opportunistic. Few infections occur due to strict pathogens. An opportunistic pathogen is an Strict pathogen is a microbe that can infect organism that normally does not essentially all human hosts who are harm its host but can cause disease, exposed to the particular microbe and cause especially when the host’s immunity essentially the same sort of infection and is low. disease symptoms in every infected person. Example: Example: Staphylococcus aureus Treponema pallidum (syphilis) Escherichia coli Plasmodium vivax (malaria) Q: What is the favourite condition for the opportunistic pathogen to cause disease ???????????? Bacterial classification ❑ Bacteria are classified into orders, families, genera and species on basis of : Morphology Staining properties Nutrition Biochemical tests Antigenic structure ❑ Bacteria can be also classified according to their habitat and way of living into saprophytic bacteria and Parasitic bacteria. ▪ Saprophytic bacteria live on inanimate material; in the soil, in water, in dust, in the air, on clothes or on dead bodies and decaying organic matter. ▪ Parasitic bacteria live on or in the body of living creatures. They classified into normal commensals (microbiota) and pathogens. Morphological study of Bacteria The bacterial morphological features of importance are the size, shape and arrangement. 1. Size of the Bacterial Cell: most of bacteria fall within the general dimensions of 0.75 to 4 um. 2. Shape of the Bacterial Cell: Bacteria may occur as: Bacilli (rod-shaped) e.g. the TB bacillus. Cocci (spherical forms) e.g. Staphylococci. Spiral forms e.g. spirochaetes. 3. Arrangement of the Bacterial Cells: Bacteria may be arranged in : Clusters (e.g. Staphylococci). Pairs (diplococci) (e.g. Pneumococci). Chains (e.g. Streptococci).  Exercises Complete the following: 1. …………….is an organism that decomposes, or breaks down, organic material. 2. Microbiology is divided by taxonomy into …………..,…….……and……………. 3. Each organism has two names …………..and………….except…………… 4. Prokaryotic microorganism like …………. 5. Chlamydia and the Rickettsiae differ from bacteria in ……………………… 6. …………………composed of few genes protected by protein coat. Define: 1) Opportunistic pathogen:………………………………………………………………………………..  Illustrate the morphological classification of bacteria according to shape. …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………………. Compare between the prokaryotic and eukaryotic. Thank You