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Chapter 17 Kingdom Monera and Viruses

Chapter 17 Kingdom Monera and Viruses. I. Introduction to the Bacteria A. Symbiotic Relationships • mutualism between luminescent bacteria and flash-light fish. B. Ancient Organisms

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Chapter 17 Kingdom Monera and Viruses

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  1. Chapter 17 • Kingdom Monera and Viruses I. Introduction to the Bacteria A. Symbiotic Relationships • mutualism between luminescent bacteria and flash-light fish. B. Ancient Organisms • known as fossils 3.5 billion years old. Fossils of eukaryotic cells are 1.5 billion years old C. Number of Species 1. About 5,000 species known 2. Occur in almost any natural habitat 3. Some species may have many different strains (Streptomyces pneumonia has 84 strains

  2. D. Pathogenic or Harmless? • more than 90% either harmless or beneficial to humans

  3. II. Features of the Kingdom Monera A. Prokaryotic Cells B. Colonies or Filaments C. Motility 1. Most nonmotile 2. Some possess bacterial flagella 3. Others move by gliding motion

  4. D. Nutrition 1. Absorption of food in solution 2. Chemosynthesis i.e. obtain their energy through chemical reactions involving various compounds or elements 3. A few bacteria such as cyanobacteria and chloroxybacteria carry on a form of photosynthesis E. Reproduction 1. Predominantly asexual by binary fission 2. Genetic recombination in several groups through the use of pili (minute tubes that allow the passage of the bacterial chromosome from the donor cell to the recipient cell

  5. III. Cellular Detail and Reproduction A. Cell Structure 1. Prokaryotic • no membrane-bound organelles 2. Nucleoid • single chromosome (long, very condensed DNA molecule in ring form) 3. Plasmids • small, circular, extrachromosomal DNA molecules

  6. B. Reproduction 1. By binary fission • a bacterium may undergo fission every 10-20 minutes 2. Conjugation • part of a chromosome is transferred from donor cell to recipient through pilus 3. Transformation • living cell picks up fragments of DNA released by dead cells 4. Transduction • fragments of DNA carried from one cell to another by viruses

  7. IV. Size, Form, and Classification of Bacteria A. Size • most are less than 2-3 µm in diameter, the smallest being around 0.15 µm B. Form 1. Cocci • spherical 2. Bacilli • rod-shaped or cylindrical 3. Spirilli • helical or spiral

  8. C. Classification 1. Based on reaction to a dye 2. Two categories a. Gram-positive b. Gram-negative 3. Stain named after Christian Gram • made observation in 1884

  9. V. Subkingdom Archaebacteriobionta: The Archaebacteria A. Distinctive Characteristics 1. Unique sequence of bases in RNA 2. Cell walls lack muramic acid 3. Production of distinctive lipids

  10. B. The Methane Bacteria 1. Anaerobic 2. Produce methane from carbon dioxide and hydrogen C. The Salt Bacteria 1. Thrive in high salinity 2. Carry on photosynthesis with the aid of bacterial rhodopsin D. The Sulpholobus Bacteria • occur in sulphur hot springs E. Human Relevance of the Archaebacteria • methane production for fuel

  11. VI. Subkingdom Eubacteriobionta: The True Bacteria (Division Eubacteriophyta) A. Class Eubacteriae—The Unpigmented, Purple, and Green Sulphur Bacteria 1. Heterotrophic bacteria a. Saprobes b. Parasites

  12. 2. Autotrophic bacteria a. Photosynthetic bacteria 1) Some produce oxygen, others sulphur 2) Pigments located in thylakoids • bacteriochlorophyll or chlorobium chlorophyll b. Chemoautotrophic bacteria 1) Obtain energy through oxidation of reduced inorganic groups (NH3, H2S) 2) Examples: iron, sulphur, and hydrogen bacteria

  13. 3. Human relevance of the Unpigmented, Purple, and Green Sulphur Bacteria a. Compost and composting b. True bacteria and disease 1) Modes of access of disease bacteria a) Access from the air ("strep throat", chlamydias) b) Access through contamination of food and drink i) Salmonella food poisoning ii) Staphylococcus food poisoning iii) Legionnaire's disease iv) Botulism

  14. c) Access through direct contact - Syphilis and Gonorrhea, Anthrax, Brucellosis d) Access through wounds - Tetanus, Gas gangrene e) Access through bites of insects and other organisms i) Bubonic plague (the "Black Death") ii) Tularemia iii) Rickettsias iv) Pleuropneumonia-like organisms (PPLOs) v) Lyme disease

  15. 2) Koch's postulates a) Microorganism must be present in all cases of the disease b) Microorganism must be isolated from the victim in pure culture c) Microorganism from pure culture, when injected into susceptible host, must produce the disease in the host d) Microorganism must be isolated from the experimentally infected host and grown in pure culture

  16. c. True bacteria useful to humans 1) Biological controls a) Bacillus thuringiensis (control of caterpillars) b) Bacillus thuringiensis (var. israelensis) • control of mosquitoes c) Bacillus popilliae (control of Japanese beetle grubs) 2) Bioremediation a) Break down of nitroglycerin and trinitrotoluene b) Pseudomonas capacia • breakdown of oil spills and chemical dumps

  17. d. Other useful bacteria 1) Research into chemistry of vision 2) Dairy industry 3) Digestive system aids (Lactobacillus acidophilus) 4) Production of metabolic wastes with industrial use 5) Food production

  18. B. Class Cyanobacteriae—The Blue-Green Bacteria 1. Introduction a. Pigments 1) Chlorophyll a 2) Phycocyanin 3) Phycoerythrin b. Can both fix nitrogen and produce oxygen 2. Distribution a. Widely distributed in fresh and marine waters b. Some precipitate carbonate deposits (travertine)

  19. 3. Form, metabolism, and reproduction a. Form 1) Cells often occur in chains or hair-like filaments 2) Some species occur as colonies 3) Color varies depending on pigments present, although half are blue-green b. Metabolism • store carbohydrates, lipids, and the nitrogenous cyanophycin c. Reproduction 1) New cells formed by fission 2) New colonies may be formed by fragmentation at: a) Heterocysts (nitrogen-fixing cells) b) Akinetes 3) Genetic recombination

  20. 4. Blue-green bacteria, chloroplasts, and oxygen a. Symbiotic origin of chloroplasts from blue-green bacteria • blue-green bacteria occur symbiotically and function essentially as chloroplasts in host organism b. Speculation that chloroplasts originated as prochlorobacteria 5. Human relevance of the blue-green bacteria a. Occur at bottom of food chains b. Production of blooms c. Poisons d. Spirulina used as food e. Undesirable effects in human water supplies f. Nitrogen fixation

  21. C. Class Prochlorobacteriae—The Prochlorobacteria 1. Discovered living on sea squirts (1976) 2. Have chlorophylls a and b, but not phycobilins 3. Thylakoid membranes double, unlike thylakoids of blue- green bacteria 4. One very abundant form found at depth of 100 m in ocean waters

  22. VII. Viruses A. Introduction 1. Smallpox a. An often fatal, communicable disease b. Has now been eradicated 2. Vaccination against smallpox • performed by Edward Jenner, a country physician, in 1796

  23. B. Size and Structure 1. Vary in diameter from 15 to 300 nm 2. Consist of nucleic acid core surrounded by a protein coat a. Nucleic acid may be DNA or RNA, but never both b. Protein coat often has 20 sides, resembling tiny geodesic domes C. Bacteriophages • viruses that attack bacteria

  24. D. Viral Reproduction 1. Viruses replicate only at the expense of their host cells 2. Viruses must become attached to a susceptible cell 3. Once inside the host cell, their DNA or RNA directs the synthesis of new viral particles 4. Some viruses mutate rapidly 5. Viruses may affect the metabolism of their host cells 6. Infected cells can produce interferon which protects uninfected cells

  25. E. Human Relevance of Viruses 1. Numerous diseases caused by viruses 2. AIDS, caused by a retrovirus called HIV 3. Production of vaccines 4. Viroids and Prions

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