Download Domain (Kingdom) Bacteria, Domain (Kingdom

Domain (Kingdom) Bacteria,
Domain (Kingdom) Archaea, and
Viruses
Chapter 17
Outline
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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
Introduction
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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
Features of Kingdoms (Domains)
Bacteria and Archaea
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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
Features of Kingdoms (Domains)
Bacteria and Archaea
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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 pili or by close
contact of cells
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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
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Ribosomes present, but about ½ size of eukaryotic cells
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Nucleoid - single chromosome in form of ring
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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
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Features of Kingdoms (Domains) Bacteria and Archaea
Cellular 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
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Features of Kingdoms (Domains) Bacteria and Archaea
Cellular 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
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Features of Kingdoms (Domains) Bacteria and Archaea
Cellular 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
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Features of Kingdoms (Domains) Bacteria and Archaea
Size, Form, and Classification of Bacteria
Most bacteria >2 or 3 μm in diameter
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Occur in 3 forms:
Cocci
Spherical or
elliptical
Bacilli
Rod-shaped or
cylindrical
Spirilla
Helix or spiral
Features of Kingdoms (Domains) Bacteria and Archaea
Size, Form, and Classification of Bacteria
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Also classified by:
• Presence of sheath around cells, hair-like or
bud-like appendages, endospores, pili or
flagella
• Color
• Mechanisms of movement
• Biochemical characteristics
• Reaction of cell walls to dye
− Gram-negative
− Gram-positive
Domain Bacteria (Kingdom Bacteria) –
The True Bacteria
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True bacteria have muramic acid in cell walls, and
different 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
Domain Bacteria (Kingdom Bacteria) –
The True Bacteria
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Phylum Bacteriophyta
• Autotrophic Bacteria - synthesize organic compounds
from simple inorganic substances
− Photosynthetic without producing O2
 Purple Sulfur Bacteria - bacteriochlorophyll
pigments, use H2S
 Purple Nonsulfur Bacteria - bacteriochlorophyll
pigments, use H2
 Green Sulfur Bacteria - chlorobium chlorophyll
pigments, use H2S
− Photosynthetic and produce O2
 Cyanobacteria and Chloroxybacteria
Domain Bacteria (Kingdom Bacteria) –
The True Bacteria
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Phylum Bacteriophyta
• Autotrophic bacteria cont’d.
− Chemotrophic Bacteria - obtain energy from
various compounds or elements through oxidation
 Iron Bacteria - transform soluble Fe to insoluble
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Sulfur Bacteria - convert H2S gas to S or S to
SO42Hydrogen Bacteria – use H2 derived from
anaerobic or N2-fixing bacteria
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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 experimentallyinfected host and grown in pure culture for
comparison with original culture
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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
Human Relevance of the Unpigmented,
Purple, and Green Sulfur Bacteria
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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
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Solvents, explosives, ascorbic acid (vitamin C),
citric acid
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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Distinctions between cyanobacteria and
traditional bacteria
• Has chlorophyll a and O2 produced from
photosynthesis
• Contain phycobilins
• Can fix N2 and produce O2
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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Distribution in 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
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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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
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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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
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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Cyanobacteria, chloroplasts, and O2
• Chloroplasts originated as cyanobacteria or
prochlorobacteria living within other cells
• Fossils of cyanobacteria, 3.5 bya, found in Australia
• 3 bya, cyanobacteria produced O2 as by-product of
photosynthesis
• O2 accumulated in atmosphere, becoming substantial
1 bya
• 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
Class Cyanobacteriae – The
Cyanobacteria (Blue-Green Bacteria)
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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
• N2 fixation
Class Prochlorobacteriae –
The Prochlorobacteria
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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 to cyanobacteria and
other true bacteria
Prochloron
Kingdom Archaea (Domain Archaea) –
The Archaebacteria
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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 CO2 and
H2
Kingdom Archaea (Domain Archaea) –
The Archaebacteria
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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
Kingdom Archaea (Domain Archaea) –
The Archaebacteria
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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
Kingdom Archaea (Domain Archaea) –
The Archaebacteria
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Human relevance of the archaebacteria
• CH4 bacteria 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
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 and
produce more virus
Papavoviruses in a human wart
particles using host cell
• About size of large molecules, 15-300 nm
Viruses
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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
Viruses
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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
Viruses
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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
Viroids and Prions
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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
Review
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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