Slide 1The Scope of MicrobiologySlide 3Microbial Involvement in Energy and Nutrient FlowHuman Use of MicroorganismsInfectious Diseases and the Human ConditionCurrent Infectious Disease TrendsMajor Groups of MicroorganismsThe General Characteristics of MicroorganismsProkaryotesEukaryotesA Note on VirusesBacteria and ArchaeaBacteria and ArchaeaFungiFungiProtozoaProtozoaAlgaeAlgaeThe Fall of Superstition and the Rise of MicrobiologyRedi’s ExperimentsNeedham’s ExperimentsSpallanzani’s ExperimentsPasteur’s ExperimentsThe Historical Foundations of MicrobiologyThe Development of the MicroscopeEstablishment of the Scientific MethodEstablishment of the Scientific MethodThe Development of Medical MicrobiologyThe Discovery of Spores and SterilizationThe Development of Aseptic TechniquesThe Discovery of Pathogens and the Germ Theory of DiseaseTaxonomy: Naming, Classifying, and Identifying MicroorganismsAssigning Specific NamesM I C R O B I O L O G YWITH DISEASES BY BODY SYSTEM SECOND EDITIONChapter 1A Brief History of MicrobiologyTHIRDThe Scope of Microbiology•Microbiology: The study of living things too small to be seen without magnification•Microorganisms: A large, diverse group of microscopic organisms that exist as single cells or cell clusters–Commonly called germs, viruses, agents, but not all cause disease and many more are useful or essential for human life–Distinct from the cells of animals and plants, which are unable to live alone in nature and can exist only as parts of multicellular organismsThe Impact of Microbes on Earth: Small Organisms with a Giant Effect•Microbes have extensively shaped the development of the Earth’s habitats and the evolution of other life forms–Bacterial-type (prokaryotic) organisms have been on Earth for ~3.5 billion years–Ubiquitous–Live in places other organisms cannot–Play central roles in processes that are essential for lifeMicrobial Involvement in Energy and Nutrient Flow•Deeply involved in flow of energy and food through Earth’s ecosystems–Photosynthesis–Anxoygenic–Oxygenic–Photosynthetic microorganisms account for >50% of Earth’s photosynthesis, contributing the majority of the oxygen to the atmosphere–Decomposition and nutrient recyclingHuman Use of Microorganisms•Humans have been using microorganisms for thousands of years–Baker’s and brewer’s yeast–Cheeses–Moldy bread on wounds•Genetic engineering: Manipulates the genetics of microbes, plants, and animals in order to create new products and GMOs–Recombinant DNA technology•Bioremediation: To restore stability or to clean up toxic pollutants using microbesInfectious Diseases and the Human Condition•Most microbes that associate with humans cause no harm and in fact provide many benefits•~ 2000 microbes that cause disease (pathogens)–<1% of all microbesCurrent Infectious Disease Trends•Increasing number of emerging and reemerging diseases (SARS, AIDS, hepatitis C, viral encephalitis)–Some advances in eradication (vaccination)•Many diseases previously thought to be noninfectious probably do involve microbial infection–Gastric ulcers, cancers, diabetes, schizophrenia, multiple sclerosis, obsessive compulsive disorder, female infertility•Immunocompromised patients•Increasing number of drug resistant strainsMajor Groups of Microorganisms•Bacteria•Algae•Protozoa•Helminths•Fungi•Viruses (acellular)The General Characteristics of MicroorganismsProkaryotes•Do not have membrane surrounding their DNA; lack a nucleus•Lack various organelles bound with phospholipid membranes•Are small, ~1.0 µm in diameter•Composed of Bacteria and Archaea•Habitats–From Antarctic glaciers to thermal hot springs–From colons of animals to cytoplasm of other prokaryotes–From distilled water to supersaturated brine–From disinfectant solutions to basalt rocks•Only a few capable of colonizing humans and causing diseaseEukaryotes•Have membrane surrounding their DNA; have a nucleus•Have internal membrane-bound organelles•Are larger, 10-100 µm in diameter•Composed of:–Fungi–Algae Microorganisms–Protozoa–Helminths Micro- and macroorganisms–Insects–Plants Macroorganisms–AnimalsA Note on Viruses•Not independently living cellular organisms•Much simpler than cells–Basically a small amount of DNA or RNA wrapped in protein and sometimes by a protein-containing lipid membrane•Extracellular state – virus particle or virion•Intracellular state – exist in the form of genetic material•Depend on the infected cell’s machinery to multiply and disperse (parasites)Bacteria and Archaea•Unicellular and lack nuclei•Most are much smaller than eukaryotes•Found everywhere there is sufficient moisture; some found in extreme environments•Reproduce asexually•Two kinds–Bacteria – cell walls contain peptidoglycan; some lack cell walls; most do not cause disease and many are beneficial–Archaea – cell walls composed of polymers other than peptidoglycanBacteria and ArchaeaFungi•Eukaryotic (have membrane-bound nucleus)•Single cells or filamentous•Obtain nutrients by breaking down organic matter–Ecologically important •Possess cell walls•Some are harmful to plants, animals, and humans, but others are useful•Composed of:–Molds – typically multicellular; have hyphae; reproduce by sexual and asexual spores–Yeasts – unicellular; reproduce asexually by budding; some produce sexual sporesFungiProtozoa•Single-celled eukaryotes that contain at least one nucleus•Similar to animals in nutrient needs and cellular structure–No cell wall•Live freely in water; some live in animal hosts•Asexual (most) and sexual reproduction•Some have complex life cycles•Most are capable of locomotion by–Pseudopodia – cell extensions that flow in direction of travel–Cilia – numerous, short, hairlike protrusions that beat rhythmically–Flagella – extensions of a cell that are fewer, longer, and more whiplike than ciliaProtozoaAlgae•Unicellular or multicellular•Photosynthetic–Make their own food from carbon dioxide and water using energy from sunlight•Found near surface of fresh or salt water•Simple reproductive structures•Categorized on the basis of pigmentation and composition of cell wall•Algae are critically important to global ecology, but they have negligible medical importanceAlgaeThe Fall of Superstition and the Rise of Microbiology•Some philosophers