Lecture 1 General introduction Microbial life Impact of microorganisms on humans Dr. Herwig Bachmann Vrije Universiteit Amsterdam Brock Biology of Microorganisms Sixteenth Edition, Global Edition Chapter 1 The Microbial World Copyright © 2022 Pearson Education Ltd. All Rights Reserved. One Exploring the Microbial World 1.1 Microorganisms, Tiny Titans of the Earth 1.2 Structure and Activities of Microbial Cells 1.3 Cell Size and Morphology 1.4 An Introduction to Microbial Life 1.5 Microorganisms and the Biosphere 1.6 The Impact of Microorganisms on Human Society Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.1 Microorganisms, Tiny Titans of the Earth (1 of 4) • – – – – Microorganisms (microbes) are life forms too small to be seen by the human eye diverse in form/function inhabit every environment that supports life many single-celled, some form complex structures, some multicellular live in microbial communities (Figure 1.1) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.1 Microbial Communities Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.1 Microorganisms, Tiny Titans of the Earth (2 of 4) • Oldest form of life • Major fraction of Earth’s biomass • Surround plants and animals • Affect human life (infectious diseases, food and water, soils, animal health, fuel) (Figure 1.2) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Exmaple How do people make money with microbiology? Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.2 Microbial Applications Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.4 Microbial Cell Structure Cellwall Cytoplasmic JohnBozzolaand M.T.Madigan membrane Nucleoid Cytoplasm Plasmid Bacteria H.Königand K.O.Stetter Ribosomes (a)Prokaryoticcell Archaea Cellwall Cytoplasmic membrane Mitochondrion Nuclear membrane Nucleus Ribosomes reticulum Cytoplasm Golgi complex Eukarya S.F.ContiandT.D.Brock Endoplasmic (b)Eukaryoticcell Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.2 Structure and Activities of Microbial Cells (3 of 5) • – – ▪ ▪ – ▪ ▪ ▪ Genes, genomes, nucleus, and nucleoid genome: a cell’s full set of genes eukaryotic DNA linear chromosomes within nucleus much larger/more DNA (up to billions of base pairs) prokaryotic DNA typically single circular chromosome that aggregates to form the nucleoid region (Figure 1.4a) may also have plasmids (extrachromosomal DNA) that confer special properties (e.g., antibiotic resistance) small, compact (0.5–10 million base pairs) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.5 The Properties of Microbial Cells Propertiesofallcells: Allcellshaveacytoplasmic membrane,cytoplasm,agenome madeofDNA,andribosomes. DNA Growth Metabolism Structure Cytoplasmic membrane Allcellsuseinformationencoded inDNAtomakeRNAandprotein. Allcellstakeupnutrients, transformthem,conserveenergy, andexpelwastes. InformationfromDNAis convertedintoproteins,which dowork.Proteinsareusedto convertnutrientsfromthe environmentintonewcells. 1.Catabolism(transforming moleculestoproduceenergy Evolution ChancemutationsinDNAcause newcellstohavenewproperties, therebypromotingevolution. Phylogenetictreesbuiltfrom DNAsequencescapture evolutionaryrelationships betweenspecies. andbuildingblocks) 2.Anabolism(synthesizing macromolecules) Distinct species Cell Ribosomes &Cytoplasm Ancestral †Environment cell Distinct species Propertiesofsomecells: Motility Differentiation Communication Somecellscanformnewcell structuressuchasaspore. Cellsinteractwitheachotherb chemicalmessengers. Cellscanexchangegenes self-propulsion. byseveralmechanisms. >Wan DNA Flagellum Spore Horizontalgenetransfer Somecellsarecapableof Donorcell Recipientcell A0001DasessCarrestionTae Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.3 Cell Size and Morphology (1 of 3) • Morphology: cell size and shape • 1 micrometer (µm or micron) = one-million of a meter • Size range for prokaryotes: 0.2 µm to 600+ µm in diameter (Table 1.1) Most are between 0.5 and 10 µm long. Examples of very large prokaryotes: Epulopiscium fishelsoni (Figure 1.6a) Thiomargarita namibiensis (Figure 1.6b) – – ▪ ▪ • Size range for eukaryotic cells: typically 5 to 100 µm in length Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.6 Two Very Large Bacteria Epulopiscium fishelsoni Thiomargarita namibiensis HeideSchulz-Vogt Parameciumcell EstherR.Angert,HarvardUniversity Epulopisciumcell (a) A0001DesecarCarrestionTe Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.7 Surface Area and Volume Relationships in Cells Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.8 Cell Morphologies Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.9 Microorganisms Vary Greatly in Size and Shape Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.4 An Introduction to Microbial Life (1 of 4) • Domains: 3 major cell lineages, Bacteria, Archaea, Eukarya • – – Bacteria (Figure 1.9) prokaryotes usually undifferentiated single cells 0.5–10 µm long but vary widely 80+ phylogenetic lineages (phyla) – Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Copyright © 2022 Pearson Education Ltd. All Rights Reserved. • – – – – – Archaea prokaryotes five well-described phyla historically associated with extreme environments, but not all extremophiles lack known parasites or pathogens of plants and animals 12+ phyla Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.4 An Introduction to Microbial Life (3 of 4) • – – – – Eukarya plants, animals, fungi first were unicellular, may have appeared two billion years ago at least six kingdoms (instead of phyla) vary dramatically in size, shape, physiology (Figure 1.9) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.4 An Introduction to Microbial Life (4 of 4) • – – – – – Viruses obligate parasites that only replicate within host cell not cells do not carry out metabolism; take over infected cells to replicate have small genomes of double-stranded or singlestranded DNA or RNA classified based on structure, genome composition, and host specificity (e.g., bacteriophages) Can you think of how to use bacteriophages to tackle the growing antibiotic resistance problem? Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Question How did microbes change the atmosphere of earth to allow evolution of higher forms of life? Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.10 A Summary of Life on Earth through Time and Origin of the Cellular Domains Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.11 Phototrophic Microorganisms Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.12 Contribution of Microbial Cells to Global Biomass Animal biomass is a minor fraction (<0.1%) of total global biomass and is not shown Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Table 1.2 Classes and Examples of Extremophilesa (1 of 2) Extreme Descriptive term Genus, species Domain Habitat Minimum Optimum Maximum Temperature High Hyperthermo phile Methanopyrus kandleri Archaea Undersea hydrother mal vents 90°C 106°C 122°C b Temperature Low Psychrophile Psychromonas ingrahamii Bacteria Sea ice −12°C c 5°C 10°C pH Low Acidophile Picrophilus oshimae Archaea Acidic hot springs −0.06 0.7d 4 pH High Alkaliphile Natronobacterium gregoryi Archaea Soda lakes 8.5 10e 12 Pressure Barophile (piezophile) Moritella yayanosii Bacteria Deep ocean sediments 500 atm 700 atmf >1000 atm Salt (NaCl) Halophile Halobacterium salinarum Archaea Salterns 15% 25% 32% (saturation) elsius elsius elsius elsius elsius elsius Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.6 The Impact of Microorganisms on Human Society (1 of 6) • – – – Microorganisms can be both beneficial and harmful to humans. agents of disease food and agriculture valuable human products, energy generation, environmental clean-up How many microbial cells are in a human body compared to the number of human cells? Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.6 The Impact of Microorganisms on Human Society (2 of 6) • – – Microorganisms as disease agents (Figure 1.13) control of infectious disease over past 120 years bacterial and viral pathogens • – – – Most microorganisms beneficial vaccination and antibiotic therapy water and wastewater treatment food safety (e.g., pasteurization) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.13 Death Rates for the Leading Causes of Death in the United States: 1900 and 2016 Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.6 The Impact of Microorganisms on Human Society (3 of 6) • – Microorganisms, agriculture, and human nutrition Many aspects of agriculture depend on microbial activities. (Figure 1.14) ▪ nitrogen-fixing bacteria ▪ cellulose-degrading microbes in rumen ▪ gut microbiome: digests complex carbohydrates in humans (Figure 1.15) – synthesize vitamins and other nutrients Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.14 Microorganisms in Modern Agriculture Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.15 The Human Gastrointestinal Tract Copyright © 2022 Pearson Education Ltd. All Rights Reserved. 1.6 The Impact of Microorganisms on Human Society (4 of 6) • – ▪ ▪ Microorganisms and food negative impacts can cause food spoilage and foodborne disease harvest, storage, safety, prevention of spoilage influenced by microbes – positive impacts (Figure 1.16) ▪ improve food safety, preservation – dairy products (e.g., cheeses, yogurt, buttermilk) – other food products (e.g., sauerkraut, kimchi, pickles, chocolate, coffee, bread, alcohol) Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.16 Fermented Foods Copyright © 2022 Pearson Education Ltd. All Rights Reserved. Figure 1.17 Industrial Microbiology Copyright © 2022 Pearson Education Ltd. All Rights Reserved.
