Micro-08105 3(2-1) GENERAL MICROBIOLOGY AND IMMUNOLOGY Dr. Shahzad Ali Assistant Professor

1. Micro-081053(2-1) GENERAL MICROBIOLOGY AND IMMUNOLOGY Dr. Shahzad Ali Assistant Professor Department of Wildlife and Ecology UVAS, Ravi Campus, Pattoki

2. Microbiology: The branch of biology that deals with microorganisms • A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye) • Commonly called “germs, viruses, agents…” but not all cause disease and many more are useful or essential for human life

3. Types of microorganism Bacteria • Simple, single-celled (unicellular) organisms • Prokaryotes • Several shapes (bacilli, cocci, spirilla) • Cell walls composed of a carbohydrate and protein complex called peptidoglycan • Reproduce by binary fission • Nutrition: • Most bacteria use organic chemical derived from living and dead organisms • Some photosynthetic • Other : inorganic substances • Swim: flagella

5. Archaea • Archaea(ar'ke-a) consist of prokaryotic cells • Cell walls lack peptidoglycan • Found in extreme environments • Three main groups • The methanogensproduce methane as a waste product from respiration • The extreme halophiles (halo = salt; philic= loving) live in extremely salty environments such as the Great Salt Lake and the Dead Sea • The extreme thermophiles (therm= heat) live in hot sulfurous water, such as hot springs at Yellowstone National Park. • None pathogenic for humans

7. Fungi • Eukaryote • Uni-cellular or multicellular • Cell wall-chitin • Yeast: unicellular • Mold: compose of long filaments (hyphae) • Mushrooms: none photosynthetic • Reproduce: asexually, sexually • Nourishmentby absorbing solutions of organic material from their environment- whether soil, seawater, fresh water, or an animal or plant host

9. Protozoa • Single-celled eukaryotes • Similar to animals in nutrient needs and cellular structure • Live freely in water; some live in animal hosts • Asexual (most) and sexual reproduction • Most are capable of locomotion by • Pseudopodia – cell extensions that flow in direction of travel • Cilia – numerous, short, hairlike protrusions that propel organisms through environment • Flagella – extensions of a cell that are fewer, longer, and more whiplike than cilia

11. Algae • Unicellular or multicellular • Photosynthetic • Sexual and asexual reproduction • Categorized on the basis of pigmentation, storage products, and composition of cell wall (mostly cellulose) • Examples (class activity)

12. virus • Acellular • Reproduce inside host • Viruses are very small and they measured in nanometers. • They can only be seen with an electron microscope. • They are composed of a core of DNA or RNA surrounded by a protein coat • Their size ranges from 20 nanometers to 250 nanometers.

13. A Brief History of Microbiology Importance of observations made by Hooke and van Leeuwenhoek • Robert Hooke observed that cork was composed of boxes“ ; he introduced the term cell (1665) • Hooke's observations laid the ground work for development of the cell theory, the concept that all living things are composed of cells • What is cell theory? (Class Activity)

14. A Brief History of Microbiology • Anton van Leeuwenhoek, (using a simple microscope, was the first to observe microorganisms (1673).

15. A Brief History of Microbiology The Debate over Spontaneous Generation • Initially people commonly believed that • Toads, snakes, and mice could be born of moist soil • Flies could emerge from manure; and • Maggots, the larvae of flies, could arise from decaying corpses • Redi’s Experiments (1668) • opponent of spontaneous generation • When decaying meat was kept isolated from flies, maggots never developed • Meat exposed to flies was soon infested • As a result, scientists began to doubt Aristotle’s theory

17. A Brief History of Microbiology • John Needham (1745) • Heated nutrient fluids before pouring them into covered flasks, the cooled solutions were soon teeming with microorganisms • Microbes developed spontaneously from the fluids • Lazzaro Spallanzani (1765) • Microorganisms from the air probably had entered Needham's solutions after they were boiled • Spallanzani showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth • Needham responded by claiming the "vital force" necessary for spontaneous generation had been destroyed by the heat and was kept out of the flasks by the seals.

19. A Brief History of Microbiology Anton Laurent Lavoisier • Showed the importance of oxygen to life. • Spallanzani'sobservations were criticized on the grounds that there was not enough oxygen in the scaled flasks to support microbial life Theory of Biogenesis • Rudolf Virchow • Challenged the case for spontaneous generation with the concept of biogenesis • The claim that living cells can arise only from preexisting living cells

20. A Brief History of Microbiology Pasteur’s Experiments (1861) • Spontaneous generation disproved by a series of experiments • Microorganisms arc present in the air • can contaminate sterile solutions • but that air itself docs not create microbes • When the “swan-necked flasks” remained upright, no microbial growth appeared • When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day

21. Pasteur’s Experiments

22. A Brief History of Microbiology • Pasteur's discoveries led to • The development of aseptic techniques* used in laboratory and medical procedures to prevent contamination by microorganisms Aseptic techniques • Techniques that prevent contamination by unwanted microorganisms, which are now the standard practice in laboratory and many medical procedures

23. A Brief History of Microbiology The Golden Age of Microbiology • The science of microbiology advanced rapidly between 1857 and 191 4 • Fermentation • Pasteurization • Germ theory • Vaccination Etc. (see figure 1.4 and Table 1.2 for detail) CLASS AVTIVITY • Summarize in your own words the germ theory of disease. 1-8 • What is the importance of Koch's postulates? 1-9 • What is the significance of Jenner's discovery? 1-10

24. A Brief History of Microbiology Koch's postulates: • The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. • The microorganism must be isolated from a diseased organism and grown in pure culture. • The cultured microorganism should cause disease when introduced into a healthy organism.

25. A Brief History of Microbiology The Birth of Modern Chemotherapy: (Dreams of a "Magic Bullet“) • Chemotherapyis the chemical treatment of a disease • Two types of chemotherapeutic agents are • Synthetic drugs (chemically prepared in the laboratory) • Antibiotics(substances produced naturally by bacteria and fungi to inhibit the growth of other microorganisms) • Paul Ehrlich introduced an arsenic-containing chemical called salvarsanto treat syphilis (1910)

26. Alexander Fleming observed that the Penicilliumfungus inhibited the growth of a bacterial culture. He named the active ingredient penicillin (1928) . • Penicillin has been used clinically as an antibiotic since the • 1940s. • Researchers arc tackling the problem of drug-resistant microbes

27. Modern Developments in Microbiology • New branches of microbiology were developed • Bacteriology. the study of bacteria • Mycology, the study of fungi, includes medical, agricultural, and ecological branches • Parasitology is the study of protozoa and parasitic worms • Immunology, the study of immunity, actually dates back in Western culture to Jenner's first vaccine in 1796 • Virology , The study of viruses

28. Recombinant DNA Technology • Microorganisms can now be genetically modified to manufacture large amounts of human hormones and other urgently needed medical substances Origins in tworelated fields • The first, microbial genetics, studies the mechanisms by which microorganisms inherit traits • The second, molecular biology, specifically studies how genetic information is carried in molecules of DNA and how DNA directs the synthesis of proteins

29. GOODLUCK