Microbiology: A Systems Approach PowerPoint to accompany Microbiology: A Systems Approach Cowan/Talaro Chapter 1 The Main Themes of Microbiology Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 1 Topics Scope of Microbiology Importance of Microorganisms Characteristics of Microorganisms History of Microbiology Taxonomy

Scope of Microbiology Immunology Public health microbiology & epidemiology Food, dairy and aquatic microbiology Agricultural microbiology Biotechnology Genetic engineering & recombinant DNA technology

Importance of Microbiology First bacteria Photosynthesis and decomposition Human use of microorganisms Infectious diseases

Bacteria appeared approximately 3.5 billion years ago. Fig. 1.1 Evolutionary timeline

Microbes are involved in photosynthesis - account for >50% of the earth’s oxygen. Decomposition – nutrient recycling. Fig. 1.2 Microbial habitats

Microbes are used to extract copper from ore, synthesize drugs and enzymes, and bioremediate contaminated water. Fig. 1.3 Microbes at work

The most common infectious diseases worldwide. Fig. 1.4 Worldwide infectious disease statistics

Characteristics of Microorganisms Procaryotic – no nucleus and organelles Eucaryotic – nucleus and organelles (mitochondria, etc.)

There is a difference between the cell structure of a procaryote and eucaryote. Viruses are neither but are considered particles. Fig. 1.5 Cell structure

There are six main types of microorganisms: 1. ) bacterium, 2 There are six main types of microorganisms: 1.) bacterium, 2.) Fungus, 3.) Algae, 4.) Virus, 5.) Protozoan, 6.) Helminth. Fig. 1.6 The six types of microorganisms

Microorganisms vary in size - 1µm to 200 nm. Fig. 1.7 The size of things

Microorganisms were first observed by Antonie van Leeuwenhoek, using a primitive microscope. Fig. 1.9 Leeuwenhoek’s microscope

The development of an experimental system that answered questions objectively was called “scientific method”. Fig. 1.10 The pattern of deductive reasoning

Scientific Method Hypothesis Experimentation Results Conclusion or theory

History of Microbiology Spores and sterilization Spontaneous generation Aseptic technique Germ theory

Spores and sterilization Some microbes in dust and air were resistant to high heat. Spores were later identified. The term “sterile” was introduced which meant completely eliminating all life forms from objects or materials.

Spontaneous generation Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter. (flies from manure, etc)

Jan Baptista van Helmont’s recipe for mice Place a dirty shirt or some rags in an open pot or barrel containing a few grains of wheat or some wheat bran, and in 21 days, mice will appear. There will be adult males and females present, and they will be capable of mating and reproducing more mice.

Recipe for bees Kill a young bull, and bury it in an upright position so that its horns protrude from the ground. After a month, a swarm of bees will fly out of the corpse.

Louis Pasteur showed microbes caused fermentation & spoilage, and disproved spontaneous generation. Fig. 1.11 Louis Pasteur

Pasteur’s Experiment Microbes being destroyed Vigorous heat Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pasteur’s Experiment Microbes being destroyed Vigorous heat is applied. Broth free of live cells (sterile) Neck on second sterile flask is broken; growth occurs. Neck intact; airborne microbes are trapped at base, and broth is sterile. (d)

Germ theory of disease Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.

Robert Koch verified the Germ theory (Koch’s postulates). Fig. 1.12 Robert Koch

Semmelwiess and Hand Washing

Aseptic technique Joseph Lister first introduced the technique in order to reduce microbes in a medical setting and prevent wound infections.

Taxonomy A system for organizing, classifying & naming living things. Primary concerns of taxonomy are classification, nomenclature, and identification.

Levels of Classification Domain Kingdom Phylum or Division Class Order Family Genus species

Notice how inclusive a kingdom can be, and how less inclusive a genus and species can be. Fig. 1.13 Sample taxonomy

Domains Developed after the five-kingdom system Eubacteria -true bacteria, peptidoglycan Archaea –odd bacteria that live in extreme environments, high salt, heat, etc Eukarya- have a nucleus, & organelles

The Domain system was developed by Dr. Woese The Domain system was developed by Dr. Woese. The basis of the Domain system is the rRNA sequence information. Fig. 1.15 Woese system

Subdivisions or Kingdoms Monerans Fungi Protists Plants Animals

The five-kingdom system became the standard until molecular biology techniques were used to develop the Domain system. Fig. 1.14 Traditional Whittaker system of classification

Evolution Classification schemes allow for a universal tree of life “phylogenetic tree”. Living things change gradually over millions of years Changes favoring survival are retained & less beneficial changes are lost.

Nomenclature Binomial (scientific) nomenclature Genus – Bacillus, always capitalized species - subtilis, lowercase Both italicized or underlined Bacillus subtilis (B. subtilis)

Identification The process of discovering and recording the traits (physical, biochemical, genetic) of organisms, thereby, placing them in a taxonomic scheme.