1. Domain (Kingdom) Bacteria, Domain (Kingdom) Archaea, and Viruses
Chapter 14
Lecture Outline
Domain (Kingdom) Bacteria, Domain (Kingdom) Archaea, and Viruses
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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 first eukaryotic cells billion years old
Bacteria found in astronomical numbers today.
Approximately 10 million to 1 billion
Much debate as to method of classification

4. Features of Kingdoms (Domains) Bacteria and Archaea
All have prokaryotic cells.
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 is distributed to new cells.
No sexual reproduction
Genetic recombination facilitated by pili or by close contact of cells.

6. Nucleoid - Single chromosome in form of ring
Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria
Folds of plasma and other membranes perform some of functions of organelles in eukaryotic cells.
Ribosomes present, but about half the size as those of eukaryotic cells.
Nucleoid - Single chromosome in form of ring
30 or 40 plasmids may 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. Replication of nucleoid
Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria
Mitosis does not occur.
Fission:
The two copies of duplicated chromosomes migrate to opposite ends of cell.
Perpendicular walls and cell membranes formed in middle of cell.
The 2 new cells separate and enlarge to original size.
Replication of nucleoid

8. New wall growing inward of dividing bacterial cell
Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria
Fission:
May undergo fission every minutes under ideal conditions
Usually exhaust food supplies and accumulate wastes
New wall growing inward of dividing bacterial cell

9. Do not produce gametes or zygotes, and do not undergo meiosis
Features of Kingdoms (Domains) Bacteria and Archaea Cellular Detail and Reproduction of Bacteria
Do not produce gametes or zygotes, and do not undergo meiosis
Three Forms of Genetic Recombination:
Conjugation
DNA transferred from donor cell to recipient cell usually through pilus (pleural: pili).
Transformation
Living cell acquires DNA fragments released by dead cells.
Transduction
DNA fragments carried from one cell to another by viruses.
Conjugation

10. Most bacteria less than 2 or 3 micrometers in diameter.
Features of Kingdoms (Domains) Bacteria and Archaea Size, Form, and Classification of Bacteria
Most bacteria less than 2 or 3 micrometers in diameter.
Occur primarily in three forms:
New pictures to be added
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, of hair-like or bud-like appendages, of endospores, of pili or of flagella
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, and are different from archaebacteria in their 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
Responsible for decay and recycling of organic matter in soil
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 oxygen
Purple sulfur bacteria - Bacteriochlorophyll pigments, use hydrogen sulfide
Purple nonsulfur bacteria - Bacteriochlorophyll pigments, use hydrogen
Green sulfur bacteria - Chlorobium chlorophyll pigments, use hydrogen sulfide
Photosynthetic and produce oxygen - Cyanobacteria and chloroxybacteria

14. Domain Bacteria (Kingdom Bacteria) – The True Bacteria
Phylum Bacteriophyta
Autotrophic bacteria
Chemotrophic bacteria - Obtain energy from various compounds or elements through oxidation
Iron bacteria - Transform soluble iron to insoluble
Sulfur bacteria - Convert hydrogen sulfide gas to sulfur or sulfur to sulfate
Hydrogen bacteria - Use molecular hydrogen derived from anaerobic or nitrogen-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:
Access from the 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:
Modes of access of disease bacteria:
Access through 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:
Modes of access of disease bacteria:
Access through direct contact - Enter through skin or mucus membranes
Syphilis, Gonorrhea, Chlamydia, anthrax, brucellosis
Access through wounds
Tetanus and gas gangrene
Access through 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 a particular microorganism is cause of a 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:
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 between traditional bacteria and cyanobacteria:
Cyanobacteria have chlorophyll a and oxygen is produced from photosynthesis.
Cyanobacteria contain phycobilins.
Cyanobacteria can both fix nitrogen and produce oxygen.

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

23. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria)
Form, metabolism, and reproduction:
Often in chains, or colonies held together by gelatinous sheaths
Cells blue-green in color in about half of the approximately 1,500 species.
Produce nitrogenous food reserve - Cyanophycin
Flagella unknown

24. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria)
Form, metabolism, and reproduction:
New cells by fission, or by fragmentation of colonies or filaments.
In Nostoc and Anabaena, fragmentation often occurs at heterocyst.
Heterocyst - Large colorless, nitrogen-fixing cell
Also produce akinetes
Akinetes - Thick-walled cells that resist adverse conditions

25. Class Cyanobacteriae – The Cyanobacteria (Blue-Green Bacteria)
Cyanobacteria, chloroplasts, and oxygen
Thought that chloroplasts originated as cyanobacteria or prochlorobacteria living within other cells.
Fossils of cyanobacteria, 3.5 billion years old, found in Australia.
3 billion years ago, cyanobacteria produced oxygen as by- product of photosynthesis.
Oxygen accumulated in atmosphere, becoming substantial 1 billion years ago.
As oxygen accumulated, other photosynthetic organisms appeared and forms of aerobic respiration developed.
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:
Cyanobacteria are among the many aquatic and photosynthetic organisms at the bottom of various food chains.
Often become abundant in bodies of fresh water in warmer months
Algal blooms
Can be poisonous to livestock
Food - Spirulina with significant vitamin content
Swimmers itch
Nitrogen fixation

27. Class Prochlorobacteriae – The Prochlorobacteria
Have chlorophylls a and b of higher plants, but no phycobilin accessory pigments like cyanobacteria
Adds to theory that chloroplasts originated from cells living within cells of other organisms
Cell structure and chemistry similar to those of cyanobacteria and other true bacteria.
Prochloron

28. Kingdom Archaea (Domain Archaea) – The Archaebacteria
Metabolism is 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 oxygen
Active only under anaerobic conditions
Energy derived from generation of methane gas from carbon dioxide and hydrogen.

29. Kingdom Archaea (Domain Archaea) – The Archaebacteria
Salt bacteria
Metabolism enables these bacteria 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 these species 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:
Methane bacteria produce methane gas as they digest organic wastes in absence of oxygen.
Methane may be used to furnish energy for engines, heating and cooking.
Methane has a high octane level and is clean and nonpolluting.
Methane produced on large-scale when organic wastes fed into methane digester.
Leftover sludge makes excellent fertilizer.

32. Papavoviruses in a human wart
Size and structure:
Represent interface between biochemistry and life
Lack cytoplasm or cellular structure
Do not grow by increasing in size or dividing
Do not respond to external stimuli
Cannot move on their own
Cannot carry on independent metabolism
Inside living cells, they express their genes and use cellular machinery to produce more virus particles.
Papavoviruses in a human wart
About size of large molecules, nanometers

33. Viruses Size and structure:
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 number of identical structural units in their cores.
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Bacteriophages - Viruses that attack bacteria

34. Bacteriophage replication
Viruses
Viral reproduction:
Viruses replicate at expense of their 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 a 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 alone amount to millions of hours.
Immunizations have dramatically decreased incidence of many viral diseases such as chicken pox, German measles, and mumps.
AIDS
Retrovirus - A virus with two identical nuclear strands
Evolves extremely quickly
About a 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 a 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