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Introduction to Microbiology

Introduction to Microbiology

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Introduction to Microbiology

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  1. Introduction to Microbiology Ms. Crosby

  2. Introduction • “microbiology’ - the study of microorganisms • organisms to small to be seen with the naked eye • except in large groups • effects of large numbers often visible • e.g., chemical reactions in soil horizons • e.g., toxin and gas production in incompletely sterilised food cans • e.g., disease in animals and plants

  3. Diversity of Microbes • Bacteria-single celled prokaryotes • Protozoa-eukaryotic, single celled, colonial, many ways of nutrition • Fungi- absorb nutrients, single celled filamentous • Viruses-acellular entities • Others- worms, insects

  4. Organizing Life’s Diversity The History of Classification • Biologists use scientific names for species because common names vary in their use. Ursus americanus American black bear

  5. Organizing Life’s Diversity 1.1 The History of Classification • When writing a scientific name, scientists use these rules: • The first letter of the genus name always is capitalized, but the rest of the genus name and all letters of the specific epithet are lowercase. • If a scientific name is written in a printed book or magazine, it should be italicized. • When a scientific name is written by hand, both parts of the name should be underlined. • After the scientific name has been written completely, the genus name will be abbreviated to the first letter in later appearances (e.g., C. cardinalis).

  6. Organizing Life’s Diversity • Each category is contained within another, and they are arranged from broadest to most specific. The History of Classification Taxonomic Categories • The taxonomic categories used by scientists are part of a nested-hierarchal system.

  7. Organizing Life’s Diversity The History of Classification Species and Genus • A named group of organisms is called a taxa. • A genus (plural, genera) is a group of species that are closely related and share a common ancestor.

  8. Organizing Life’s Diversity The History of Classification Family • A family is the next higher taxon, consisting of similar, related genera.

  9. Organizing Life’s Diversity The History of Classification Higher Taxa • An order contains related families. • A class contains related orders. • A phylum or division contains related classes. • The taxon of related phyla or divisions is a kingdom. • The domain is the broadest of all the taxa and contains one or more kingdoms.

  10. Classification of Microbes Taxonomic Hierarchy Domain Kingdom Phylum Class Order Family Genus Species Dumb Kings Play Chess On Funny Green Squares

  11. Classification of Microbes Taxonomic Hierarchy Domain Kingdom Phylum Class Order Family Genus Species Binomal Nomenclature uses the Genus and Species name to identify each creature.

  12. Chapter 1 The Microbial World and You

  13. Scientific Names • Staphylococcus aureus • Describes the clustered arrangement of the cells (staphylo-) and the golden color of the colonies (aur-).

  14. Scientific Names • Escherichia coli • Honors the discoverer, Theodor Escherich, and describes the bacterium’s habitat–the large intestine or colon.

  15. Scientific Names • After the first use, scientific names may be abbreviated with the first letter of the genus and the specific epithet: • Staphylococcus aureus and Escherichia coli are found in the human body. S. aureus is on skin and E. coli in the large intestine.

  16. Organizing Life’s Diversity Domains and Kingdoms Grouping Species • The broadest category in the classification used by most biologists is the domain. • The most widely used biological classification system has six kingdoms and three domains. • The three domains are Bacteria, Archaea, and Eukarya. • The six kingdoms are Bacteria, Archaea, Protists, Fungi, Plantae, and Animalia.

  17. Organizing Life’s Diversity Domains and Kingdoms Domain Bacteria • Eubacteria are prokaryotes whose cell walls contain peptidoglycan. • Eubacteria are a diverse group that can survive in many different environments.

  18. Bacteria • Prokaryotes • Peptidoglycan cell walls • Binary fission • For energy, use organic chemicals, inorganic chemicals, or photosynthesis Figure 1.1a

  19. Organizing Life’s Diversity Domains and Kingdoms Domain Archaea • Archaea are thought to be more ancient than bacteria and yet more closely related to our eukaryote ancestors. • Archaea are diverse in shape and nutrition requirements. • They are called extremophiles because they can live in extreme environments.

  20. Archaea: • Prokaryotic • Lack peptidoglycan • Live in extreme environments • Include: • Methanogens • Extreme halophiles • Extreme thermophiles Halobacteria not from book

  21. Organizing Life’s Diversity Domains and Kingdoms Domain Eukarya • All eukaryotes are classified in Domain Eukarya. • Domain Eukarya contains Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia.

  22. Protists are eukaryotic organisms that can be unicellular, colonial, or multicellular. Organizing Life’s Diversity Domains and Kingdoms Kingdom Protista • Protists are classified into three different groups—plantlike, animal-like, and funguslike.

  23. Protozoa • Eukaryotes • Absorb or ingest organic chemicals • May be motile via pseudopods, cilia, or flagella • Most free some parasites Figure 1.1c

  24. A fungus is a unicellular or multicellular Organizing Life’s Diversity eukaryote that absorbs nutrients from organic materials in its environment. • Member of Kingdom Fungi are heterotrophic, lack motility, and have cell walls. Domains and Kingdoms Kingdom Fungi

  25. Organizing Life’s Diversity • Most plants are autotrophs, but some are heterotrophic. Domains and Kingdoms Kingdom Plantae • Members of Kingdom Plantae form the base of all terrestrial habitats. • All plants are multicellular and have cell walls composed of cellulose.

  26. Organizing Life’s Diversity Domains and Kingdoms Kingdom Animalia • All animals are heterotrophic, multicellular eukaryotes. • Animal organs often are organized into complex organ systems. • They live in the water, on land, and in the air.

  27. Organizing Life’s Diversity Domains and Kingdoms

  28. Organizing Life’s Diversity Domains and Kingdoms Viruses—An Exception • A virus is a nucleic acid surrounded by a protein coat. • Viruses do not possess cells, nor are they cells, and are not considered to be living. • Because they are nonliving, they usually are not placed in the biological classification system.

  29. Viruses • Acellular • Consist of DNA or RNA core • Core is surrounded by a protein coat • Coat may be enclosed in a lipid envelope • Viruses are replicated only when they are in a living host cell Figure 1.1e

  30. Multicellular Animal Parasites • Eukaryote • Multicellular animals • Parasitic flatworms and round worms are called helminths. • Microscopic stages in life cycles. Figure fluke

  31. Multicellular Parasites • Worms, insects

  32. Modern Developments in Microbiology • Bacteriology is the study of bacteria. • Mycology is the study of fungi. • Parasitology is the study of protozoa and parasitic worms. • Recent advances in genomics, the study of an organism’s genes, have provided new tools for classifying microorganisms.

  33. Modern Developments in Microbiology • Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases. • The use of immunology to identify some bacteria according to serotypes (variants within a species) was proposed by Rebecca Lancefield in 1933. Figure 1.4 (3 of 3)

  34. Modern Developments in Microbiology • Virology is the study of viruses. • Recombinant DNA is DNA made from two different sources. In the 1960s, Paul Berg inserted animal DNA into bacterial DNA and the bacteria produced an animal protein. • Recombinant DNA technology, or genetic engineering, involves microbial genetics and molecular biology.

  35. Microbes and Human Welfare • Microbial ecology • Bacteria recycle carbon, nutrients, sulfur, and phosphorus that can be used by plants and animals.

  36. Bioremediation • Bacteria degrade organic matter in sewage. • Bacteria degrade or detoxify pollutants such as oil and mercury. UN 2.1

  37. Biological Insecticides • Microbes that are pathogenic to insects are alternatives to chemical pesticides in preventing insect damage to agricultural crops and disease transmission. • Bacillus thuringiensis infections are fatal in many insects but harmless to other animals, including humans, and to plants.

  38. Modern Biotechnology and Genetic Engineering • Biotechnology, the use of microbes to produce foods and chemicals, is centuries old. • Genetic engineering is a new technique for biotechnology. Through genetic engineering, bacteria and fungi can produce a variety of proteins including vaccines and enzymes.

  39. Modern Biotechnology and Genetic Engineering (continued) • Missing or defective genes in human cells can be replaced in gene therapy. • Genetically modified bacteria are used to protect crops from insects and from freezing.

  40. Microbes and Human Disease • Bacteria were once classified as plants giving rise to use of the term flora for microbes. • This term has been replaced by microbiota. • Microbes normally present in and on the human body are called normal microbiota.

  41. Normal Microbiota • Normal microbiota prevent growth of pathogens. • Normal microbiota produce growth factors such as folic acid and vitamin K. • Resistance is the ability of the body to ward off disease. • Resistance factors include skin, stomach acid, and antimicrobial chemicals. • Biofilms are extremely important in microbial ecology

  42. Infectious Diseases • When a pathogen overcomes the host’s resistance, disease results. • Emerging infectious diseases (EID): New diseases and diseases increasing in incidence.

  43. Emerging Infectious Diseases • West Nile encephalitis • West Nile virus • First diagnosed in the West Nile region of Uganda in 1937 • Appeared in New York City in 1999

  44. Emerging Infectious Diseases • Avian Influenza A H5N1 • Severe acute respiratory syndrome (SARS) • West Nile encephalitis (WNE) • Bovine spongiform encephalitis (BSE) • Creutzfeld-Jacob disease (CJD) • 0157:H7 E. coli • Flesh eating bacteria • Ebola • Marburg • Cryptosporidiosis • AIDS • HIV virus

  45. Emerging Infectious Diseases • Bovine spongiform encephalopathy • Prion • Also causes Creutzfeldt-Jakob disease (CJD) • New variant CJD in humans is related to cattle fed sheep offal for protein

  46. Emerging Infectious Diseases • Escherichia coli O57:H7 • Toxin-producing strain of E. coli • First seen in 1982 • Leading cause of diarrhea worldwide

  47. Emerging Infectious Diseases • Invasive group A Streptococcus • Rapidly growing bacteria that cause extensive tissue damage • Increased incidence since 1995

  48. Emerging Infectious Diseases • Ebola hemorrhagic fever • Ebola virus • Causes fever, hemorrhaging, and blood clotting • First identified near Ebola River, Congo • Outbreaks every few years

  49. Emerging Infectious Diseases • Avian influenza A • Influenza A virus (H5N2) • Primarily in waterfowl and poultry • Sustained human-to-human transmission has not occurred yet • Swine Flu – (H1N1) – expected to be a pandemic for the next 3 years. May infect >1billion people