Microbial biology

NONG LAM UNIVERSITY HO CHI MINH CITY FACULTY OF BIOLOGICAL SCIENCES MICROBIAL BIOLOGY Course code: 211318 Lecturer: Biện Thị Lan Thanh, PhD Email: bienthilanthanh@hcmuaf.edu.vn Contents Lecture 1: General Introduction Lecture 2: Microscopes and the Study of Microbial Structure Lecture 3: Prokaryotes (Bacteria and Archaea) Lecture 4: Eukaryotes (Yeast, Fungi, Protozoa, Algae) Lecture 5: Virus Lecture 6: Microbial Nutrition, Growth and Control Lecture 7: Microbial Metabolism Lecture 8: Microbial Diversity and Taxonomy Lecture 9: Microbial Genetics Lecture 10: Microbial Diseases Lecture 11: Benefits and Uses of Microorganisms Textbooks Willey J M., Sherwood L M., and Woolverton C J 2009 Prescott’s Principles of Microbiology McGraw-Hill, 847 pages (ebook) • References: Madigan M.T., Martinko J.M., and Parker J Biology of Microorganisms, 10th ed Prentice Hall, Pearson Education, Inc, 1019 pages Prescott L.M., Harley J.P and Klein D.A Microbiology, 6th ed McGraw Hill, 992 pages Ingraham J.L and Ingraham C.A Introduction to Microbiology, 3th ed Thomson, 737 pages Nguyễn Lân Dũng, Nguyễn Đình Quyến Phạm Văn Ty Vi sinh vật học, tái lần thứ sáu Nhà xuất giáo dục, 519 trang Microorganism and Microbiology Microbiology the study of Organisms too small to be seen clearly by naked eye Three major divisions in biology Virus Bacteria Microscope Microorganisms Botany Fungi Algae Zoology Protozoa Microbiology The Science of Microbiology Microbiology revolves around two themes: Understanding basic life processes Applying that knowledge to the benefit of humans A ‘microbiome’ is defined as the collection of microbes or microorganisms inhabiting an environment, creating a mini-ecosystem Microbiome = Microflora = Microbiota Small intestine Large intestine (colon) Intestine = Gut Probiotic + Prebiotic = symbiotic Antibiotic Prof Rob Knight, from University of California San Diego, told the BBC: "You're more microbe than you are human" Major Fields of Pure Sciences Bacteriology Microbial ecology Mycology Microbial Physiology Virology Microbial taxonomy Microbiology Protozoology Microbial morphology Algology or Phycology Microbial genetics & Molecular Biology Parasitology The Impact of Microorganisms on Humans Microbial Cells - The cell is the fundamental unit of life - All cells are made up of four chemical components: • Proteins • Nucleic acids • Polysaccharides • Lipids Some Important Terms • Symptoms: o Evidence of disease that is experienced or perceived o Subjective changes in body function noted by patient but not apparent to an observer • Sign: Objective evidence of a disease the physician can observe and measure • Syndrome: A specific group of signs and symptoms that accompany a particular disease Some Important Terms • Infection: An infection is the invasion and multiplication of microbes in an individual or population • Infectious disease: ❑ Is a disease caused by a microbe ❑ Disease is when the infection causes damage to the individual’s vital functions and systems An infection does not always results in disease Chain of Infection Mechanism of microbial pathogenicity • To cause disease, most pathogens must gain access to the host → adhere to host tissues → penetrate or evade host defenses damage the host tissues • However, some microbes not cause disease by directly damaging host tissue Instead, disease is due to the accumulation of microbial waste products Source/reservoir of infection - Pathogens • Once these pathogens are inside your body they cause disease because they reproduce rapidly • Bacteria this by splitting in two The often produce toxin at the same time • Viruses actually take over cells, damaging and destroying them Reservoir and Susceptible host • Reservoir o A supply of pathogen/infection/disease o For example, female anopheles mosquito is a reservoir of Plasmodium falciparum for malaria • Susceptible host o Likely or liable to be influenced or harmed by a pathogen Reservoir and Susceptible host both are equally dangerous Portals of Entry Adherence • Adhesions/ligands bind to receptors on host cells o Glycocalyx o Fimbriae o M protein o Opa protein o Tapered end • Streptococcus mutans Escherichia coli Streptococcus pyogenes Neisseria gonorrhoeae Treponema pallidum Penetrate Host Defenses • Enzymes o Coagulase o Kinases o Hyaluronidase hyaluronic acid o Collagenase o IgA proteases antibodies • Antigenic variation o Alter surface proteins • Coagulate blood Digest fibrin clots Hydrolyses • Hydrolyzes collagen Destroy IgA Damage Host Cells • Direct Damage • Using the Host's Nutrient: Siderophores oTake iron from host iron-binding proteins • The Production of Toxins oProduction of toxins (endotoxin; exotoxin) Mode of Transmission • Contact Transmission o Direct Contact Transmission ✓Person to person transmission No intermediate object is involved ✓ Examples: Touching o Indirect Contact Transmission ✓Agent is transferred via a nonliving object ✓Examples: towels, eating utensils, thermometers, stethoscopes, bedding, clothes, money, and syringes o Droplet Transmission ✓Microbes are spread in mucus droplets that travel short distance (less than meter) ✓ Examples: sneezing, coughing, talking and laughing Mode of Transmission • Vehicle Transmission Transmission of disease via medium such as water, food, air, blood, body fluids, and intravenous fluids o Waterborne Transmission ✓Usually caused by water contaminated with sewage o Airborne Transmission ✓Spread of agents by droplets in dust that travel more than m to host Mode of Transmission • Vector Transmission Animals that carry disease from one host to another, Arthropods (insects) are most important animal vectors o Mechanical Transmission ✓Passive transport of pathogens on insect’s body For example: Bee o Biological Transmission ✓Pathogen spends part of its life cycle in the vector For example: Mosquito