Domain (Kingdom) Bacteria, Domain (Kingdom) Archaea , and Viruses

1. Domain (Kingdom) Bacteria, Domain (Kingdom) Archaea, and Viruses Chapter 17

2. Outline • Introduction • Features of Kingdoms (Domains) Bacteria and Archaea • Domain Bacteria (Kingdom Bacteria) – The True Bacteria • Human Relevance of the Unpigmented Purple, and Green Sulfur Bacteria • Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Class Prochlorobacteriae – The Prochlorobacteria • Kingdom Archaea (Domain Archaea) – The Archaebacteria • Viruses • Viroids and Prions

3. Introduction • Fossils of bacteria - 3.5 billion years old • Fossils of 1st eukaryotic cells - 1.3 billion years old • 5,000 species of bacteria recognized today • Each species found in astronomical numbers • Difficult to classify simple one-celled organisms = # of bacteria species uncertain • Strains of one species look alike • Clustered by what they do

4. Features of Kingdoms (Domains) Bacteria and Archaea • All have prokaryoticcells • No nuclear envelopes • Have long circular strand of DNA, ribosomes, membranes and plasmids • No membrane-bound organelles, such as plastids, mitochondria, dictyosomes, endoplasmic reticulum Section of Prochloron cell

5. Features of Kingdoms (Domains) Bacteria and Archaea • Nutrition • Primarily by absorption of food in solution through cell wall • Some by chemical reactions or by photosynthesis • Reproduction predominately asexual, by fission • Fission -no mitosis, DNA strand duplicates and distributed to new cells • No sexual reproduction • Genetic recombination facilitated by pilior by close contact of cells

6. Features of Kingdoms (Domains) Bacteria and ArchaeaCellular Detail and Reproduction of Bacteria • Folds of plasma and other membranes perform some of functions of organelles in eukaryotic cells • Ribosomes present, but about ½ size of eukaryotic cells • Nucleoid - single chromosome in form of ring • 30 or 40 plasmidsmay be present • Plasmids - small circular DNA molecules that replicate independently of chromosome • Entire complement of plasmids consists of multiple copies of one or few different DNA molecules

7. Features of Kingdoms (Domains) Bacteria and ArchaeaCellular Detail and Reproduction of Bacteria • Mitosis does not occur • Fission • 2 copies of duplicated chromosomes migrate to opposite ends of cell • Perpendicular walls and cell membranes formed in middle of cell • 2 new cells separate and enlarge to original size Replication of nucleoid

8. Features of Kingdoms (Domains) Bacteria and ArchaeaCellular Detail and Reproduction of Bacteria • Fission cont’d. • May undergo fission every 10 - 20 minutes under ideal conditions • Usually exhaust food supplies and accumulate wastes New wall growing inward of dividing bacterial cell

9. Features of Kingdoms (Domains) Bacteria and ArchaeaCellular Detail and Reproduction of Bacteria • No gametes or zygotes, and no meiosis • 3 Forms of Genetic Recombination: • Conjugation - DNA transferred from donor cell to recipient cell usually through pilus (plural: pili) • Transformation - living cell acquires DNA fragments released by dead cells • Transduction - DNA fragments carried from one cell to another by viruses Conjugation

10. Features of Kingdoms (Domains) Bacteria and Archaea Size, Form, and Classification of Bacteria • Most bacteria >2 or 3μmin diameter • Occur in 3 forms: • Spirilla • Helix or spiral • Cocci • Spherical or elliptical • Bacilli • Rod-shaped or cylindrical

11. Features of Kingdoms (Domains) Bacteria and Archaea Size, Form, and Classification of Bacteria • Also classified by: • Presence of sheath around cells, hair-like or bud-like appendages,endospores,pili orflagella • Color • Mechanisms of movement • Biochemical characteristics • Reaction of cell walls to dye • Gram-negative • Gram-positive

12. Domain Bacteria (Kingdom Bacteria) – The True Bacteria • True bacteria have muramic acid in cell walls, anddifferent from archaebacteria in RNA bases, metabolism and lipids • Phylum Bacteriophyta • Class Bacteriae -unpigmented, purple, and green sulfur bacteria • Most heterotrophic -cannot synthesize own food • Majority saprobes -food from nonliving organic matter • Some parasites -depend on living organisms for food

13. Domain Bacteria (Kingdom Bacteria) – The True Bacteria • Phylum Bacteriophyta • Autotrophic Bacteria -synthesize organic compounds from simple inorganic substances • Photosynthetic without producing O2 • Purple Sulfur Bacteria -bacteriochlorophyllpigments, use H2S • PurpleNonsulfur Bacteria -bacteriochlorophyllpigments, use H2 • Green Sulfur Bacteria -chlorobiumchlorophyll pigments, use H2S • Photosynthetic and produce O2 • CyanobacteriaandChloroxybacteria

14. Domain Bacteria (Kingdom Bacteria) – The True Bacteria • Phylum Bacteriophyta • Autotrophic bacteria cont’d. • Chemotrophic Bacteria -obtain energy from various compounds or elements through oxidation • Iron Bacteria -transform soluble Fe to insoluble • Sulfur Bacteria -convert H2S gas to S or S to SO42- • Hydrogen Bacteria – use H2derived from anaerobic or N2-fixing bacteria

15. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • Composting and compost • Bacteria decompose organic waste to form compost • True bacteria and disease • Bacteria involved in diseases of plants, animals and humans, and in losses of food • Modes of access of disease bacteria • Air • Coughs, sneezes - saliva droplets contain bacteria • Diphtheria, whooping cough, some meningitis forms, pneumonia, strep throat, tuberculosis

16. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • True bacteria and disease cont’d. • Modes of access of disease bacteria cont’d. • Contamination of food and drink • Food poisoning and diseases associated with natural disasters • Cholera, dysentery, Staphylococcus and Salmonella food poisoning • Legionnaire disease • Botulism • Escherichia coli

17. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • True bacteria and disease cont’d. • Modes of access of disease bacteria cont’d. • Direct contact - enter through skin or mucus membranes • Syphilis, Gonorrhea, anthrax, brucellosis • Wounds • Tetanus and gas gangrene • Bites of insects and other organisms • Bubonic plague, tularemia, rickettsias, mycoplasmas, Lyme disease

18. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • Koch’s Postulates -rules for proving particular microorganism cause of particular disease • Microorganism must be present in all cases of disease • Microorganism must be isolated from victim in pure culture • Microorganisms from pure culture must be able to infect hosts • Microorganism must be isolated from experimentally-infected host and grown in pure culture for comparison with original culture

19. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • True bacteria useful to humans • Biological Control organisms • Bacillus thuringiensis - effective against caterpillars and worms • Multiplies in digestive tract and paralyzes gut • Bacillus popilliae -effective against Japanese beetle grubs • Bioremediation -use of living organisms in cleanup of toxic waste and pollution Affect of Bacillus thuringiensis on tomato hornworm

20. Human Relevance of the Unpigmented, Purple, and Green Sulfur Bacteria • True bacteria useful to humans cont’d. • Other useful bacteria • Human health - Lactobacillus acidophilus • Aids in digestion • Used for elimination of yeast infections • Dairy - buttermilk, sour cream, yogurt, cheese • Industrial - utilizes bacteria waste products • Solvents, explosives, ascorbic acid (vitamin C), citric acid

21. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Distinctions betweencyanobacteria and traditional bacteria • Has chlorophyll a and O2 produced from photosynthesis • Contain phycobilins • Can fix N2and produce O2

22. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Distributionin diverse variety of habitats • Pools and ditches, particularly if polluted • Fresh and marine water, but not acidic water (plankton) • Waters of various temperatures - hot springs at Yellowstone National Park • Often 1st photosynthetic organisms after volcanic eruption • Symbiotic with other organisms Yellowstone • Amoebae, sea anemones, lichens, cycads

23. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Form, metabolism, and reproduction • Often chains, or colonies held together by gelatinous sheaths • Cells blue-green in color in ca. 50% of approximately 1,500 spp. • Produce nitrogenous food reserve -cyanophycin • Flagella unknown

24. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Form, metabolism, and reproduction cont’d. • New cells by fission or fragmentation of colonies or filaments • Heterocyst - large colorless, N2-fixing cell • Akinetes-thick-walled cells that resist adverse conditions

25. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Cyanobacteria, chloroplasts, and O2 • Chloroplasts originated as cyanobacteria or prochlorobacteria living within other cells • Fossils of cyanobacteria, 3.5bya, found in Australia • 3bya, cyanobacteria produced O2as by-product of photosynthesis • O2accumulated in atmosphere, becoming substantial 1bya • Accumulation of O2 resulted in appearance of other photosynthetic organisms and forms of aerobic respiration • In last half billion years enough ozone for UV shield and for photosynthetic organisms to survive on land

26. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Human relevance of the cyanobacteria • Among many aquatic and photosynthetic organisms at bottom of various food chains • Often abundant in bodies of fresh water in warmer months • Algal Blooms - can be poisonous to livestock • Food - Spirulina with significant vitamin content • Swimmers itch • N2fixation

27. Class Prochlorobacteriae – The Prochlorobacteria • Have chlorophylls a and b, but no phycobilins • Adds to theory that chloroplasts originated from cells living within cells of other organisms • Cell structure and chemistry similar tocyanobacteriaand other true bacteria Prochloron

28. Kingdom Archaea (Domain Archaea) – The Archaebacteria • Metabolism fundamentally different from other lines of bacteria • Differ from true bacteria by unique sequences of bases in RNA, by lack of muramic acid in walls, and by production of distinct lipids • Methane Bacteria • Killed by O2 • Active only under anaerobic conditions • Energy from generation of CH4 from CO2and H2

29. Kingdom Archaea (Domain Archaea) – The Archaebacteria • Salt Bacteria • Metabolism enables to thrive under extreme salinity • Carry out simple photosynthesis with aid of bacterial rhodopsin Lake Bonneville, Utah with very high salt content

30. Kingdom Archaea (Domain Archaea) – The Archaebacteria • Sulfolobus Bacteria • Occur in sulfur hot springs • Metabolism allows to thrive at very high temperatures • Mostly in vicinity of 80oC (170oF), some even higher • Shape of ribosomes and chemistry of sulfolobus bacteria distinguishes them from other archaebacteria, true bacteria and eukaryotes

31. Kingdom Archaea (Domain Archaea) – The Archaebacteria • Human relevance of the archaebacteria • CH4bacteria produce CH4 as they digest organic wastes in absence of O2 • May be used to furnish energy for engines, heating and cooking • Has high octane level and clean and nonpolluting • Produced on large-scale when organic wastes fed into CH4 digester • Leftover sludge makes excellent fertilizer

32. Viruses • Size and structure: • Represent interface between biochemistry and life • Lack cytoplasm or cellular structure • Don’t grow by increasing in size or dividing • Don’t respond to external stimuli • Can’t move on their own • Can’t carry on independent metabolism • Express their genes andproduce more virus particles using host cell Papavoviruses in a human wart • About size of large molecules, 15-300 nm

33. Viruses • Size and structure cont’d. • Consist of nucleic acid core surrounded by protein coat • Architecture of protein coat varies • 20-sided, or head and tail • Core consists of DNA or RNA, not both • Classified according to DNA or RNA, then according to size and shape, nature of protein coats, and # of identical structural units in cores Bacteriophage • Bacteriophages -viruses that attack bacteria

34. Viruses • Viral reproduction • Viruses replicate at expense of host cells • Attach to susceptible cell • Penetrate to cell interior • DNA or RNA dictates synthesis of new molecules • New viruses released from host cell • Host cell dies • Some can mutate very rapidly • As result, new vaccines need to be developed Bacteriophage replication

35. Viruses • Human relevance of viruses • Annual loss in work time due to common cold and influenza viruses amount to millions of hours • Immunizations dramatically decreased incidence of many viral diseases (i.e., chicken pox, German measles, and mumps) • AIDS • Retrovirus -virus with 2 identical nuclear strands • Evolves extremely quickly • ~1 million times faster than cellular organisms • Used to infect disease organisms of animals and plants • Ticks, insects, possibly gypsy moths

36. Viroids and Prions • Viroids -circular strands of RNA that occur in nuclei of infected plant cells • Transmitted from plant to plant via pollen, ovules, or machinery • Cause more than dozen plant diseases • Prions -appear to be particles of protein that cause diseases of animals and humans • Believed to cause disease by inducing abnormal folding of proteins in brain, resulting in brain damage • Cruetzfeldt-Jacob disease

37. Review • Introduction • Features of Kingdoms (Domains) Bacteria and Archaea • Domain Bacteria (Kingdom Bacteria) – The True Bacteria • Human Relevance of the Unpigmented Purple, and Green Sulfur Bacteria • Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria) • Class Prochlorobacteriae – The Prochlorobacteria • Kingdom Archaea (Domain Archaea) – The Archaebacteria • Viruses • Viroids and Prions