Prokaryotes and Protists

1
Prokaryotes and Protists

• Chapter 16

2
Organizing Life

• Domains
• What are they?
• Linnaean hierarchy
• Arrangement of taxons
• http//animaldiversity.ummz.umich.edu/site/index.h
  tml
• Tree of Life
• Branched organization
• http//www.tolweb.org/tree/
• Cell Types
• Prokaryotes or eukaryotes

3
Comparing Cell Types

• Eukaryotes

• Prokaryotes

• 1-5 um in size
• 10Xs more biomass
• Wider range of environments
• Greater diversity
• Single, circular chromosome
• Can live without eukaryotes

• 10-100 um in size
• 10Xs larger in size
• Membrane bound nucleus and organelles
• DNA arranged on multiple chromosomes
• Cant live without prokaryotes

4
Prokaryotic Shapes

• Cocci
• Sperical
• Chains or clusters
• E.g streptococci and staphylococci (MRSA and
  beta-lactams)
• Bacilli
• Rod shaped
• Occur singularly, in pairs, or chains
• E.g. soil organisms
• Spirochetes
• Corkscrew shaped
• E.g. Borrelia burgdorferi (Lyme disease)

5
Prokaryote Characteristics

• Cell wall
• Maintains shape, provides protection, and
  prevents lysis
• Salt and curing meats
• Gram stains identifed as gram () or gram (-)
• () simple walls with thicker peptidoglycan
  (sugar polymer)
• (-) more complex walls with less peptidoglycan
• More resistant to antibiotics
• Capsule
• Sticky polysaccharides or proteins to adhere to
  substrates
• Prevent immune system attacks
• Pili
• Hair-like appendages for adhesion
• Specialized for DNA transfer

6
Prokaryotic Characteristics

• Motility
• Many utilize a flagella
• Reproduction
• Review division by binary fission
• Occurs quickly (E. coli overnight from 1 to 16
  million)
• Adaptation
• Form resistant structures like endospores during
  inhospitable times
• Bacillus anthracis (anthrax) and Clostridium
  botulinum (botulism)
• Internal Organization
• All DNA is actively used
• Lack junk DNA found in eukaryotes called
  __________?
• Small genetic rings that aid in resistance called
  plasmids
• Smaller ribosomal efficiency of antibiotics

7
Prokaryotic Nourishment

• Unmatched diversity in nutrient attainment
• Nutrients provide energy and carbon
• Naming
• Photo- or chemo- energy source
• Auto- or hetero- carbon source
• -troph to eat

8
Biofilms

• Surface coating colonies of prokaryotes
• Signal to recruit more cells and produce sticky
  proteins
• E.g. dental plaque, UTIs, or sewer treatment
• Can be 1 species
• Channels provide nutrients to entire colony

9
Prokaryotes

• Archaea
• Live where other organisms cant survive,
  extremophiles
• Thermophiles
• Very hot water such as geysers and hot springs
• Halophiles
• Salt environments such as the Great Salt Lake and
  salt farms
• Methanogens
• Animal guts and swamps where they produce methane
  gas
• Bacteria
• Few species are pathogens, disease-causing
  organisms
• Most not harmful to humans

10
9 Bacterial Clades

• Proteobacteria (5 subgroups)
• Gram negative
• Gram positive
• Chlamydias
• Spirochetes
• Cyanobacteria

11
Proteobacteria

• Alpha (a)
• Rhizobium ? root nodules, fix N2
• Foreign DNA carriers into crop plant genomes
• Gamma (?)
• Photosynthetic examples
• Animal intestine inhabitants
• E.g Salmonella, Vibrio cholerae, and Escheria
  coli
• Delta (d)
• Slime secreting myxobacteria
• Can form fruiting bodies for selves when food is
  scarce
• Bdellovibrio attacks other bacteria

Salmonella
Myxobacteria
12
Gram Positive

• Actinomycetes
• Branched chains of cells or are solitary
• Pathogenic or free-living
• Mycobacteria leprae and mycobacteria tuberculosis
• Live in soil and give it the earthy smell
• Streptomyces
• Cultured by pharmaceutical companies as
  antibiotics
• Bacillus anthracis
• Form endospores, a cell within a cell that
  dehydrates and lies dormant till more favorable
  conditions exist
• Staphylococcus and streptococcus
• Mycoplasmas
• Lack cell walls
• Tiniest of all known cells

Bacillus anthracis
13
Other Bacterial Clades

• Chlamydias
• Obligate intracellular parasite
• Common cause of blindness (developing countries
  conjunctivitis) and most common STD (United
  States)
• Spirochetes
• Spiral through environments by rotating internal
  filaments
• E.g Treponema pallidum (syphilis) and Borrelia
  burgdorferi (Lyme disease)
• Cyanobacteria
• Only Only prokaryote
• Food for freshwater and marine ecosystems

Chlamydia
14
Bacterial Poisons

• Exotoxins are proteins secreted by bacteria
• Clostridium tetani produces muscle spasms
  (lockjaw)
• Staphylococcus aureus common on skin and in nasal
  passages
• Produces multiple types
• TSS, septicemia, and pneumonia
• Can be acquired from genetic transfer between
  species
• E. coli ?Acquires genes that produce harmful
  effects
• Endotoxins are components of gram (-) outer
  membranes
• Released when cell dies or digested by defensive
  cell
• All cause same general symptoms (fever, aches,
  and blood pressure drops)
• Neisseria meningitidis (bacterial meningitis) and
  Salmonella (typhoid fever and salmonellosis)

15
Bacteria, Human Populations, Disease

• Improvements in sanitation
• Water treatment and sewer systems
• Antibiotic development
• Increase in bacterial resistance
• Education
• Importance of seeking treatment
• Prevention
• Biological weapons
• Bioremediation

16
Protists

• Single or multicellular eukaryotes
• Source of food and parasites
• Autotrophic (algae) or heterotrophic (protozoan)
• Found in/near water (most) or in animal host

17
Protist Clades

• Regularly changing hypotheses
• Divergence not truly simultaneous
• Eukaryotic origin is unknown

18
Diplomonads and Parabasalids

• Heterotrophs with altered mitochondria
• Diplomonads
• Possibly most ancient Protist lineage
• Mitochondria lack DNA ETC
• Anaerobic
• E.g Giardia intestinalis backpackers disease
• Parabasalids
• Anaerobic energy generation
• E.g Trichomonas vaginalis (Trichomoniasis)
• Lives in the vagina
• pH shift to basic growth
• Feed on WBC and bacteria
• Males rarely symptomatic b/c food availability
  limits population size
• Treatment is available, but resistance is
  increasing

19
Euglenozoans

• Flagella have a crystalline rod structure
• Heterotrophs, photoautotrophs, pathogenic
  parasites
• E.g Trypanosoma
• Causes sleeping sickness
• Spread by African tsetse fly
• Avoid detection by changing protein structure
• E.g Euglena
• Common in pond water
• Reproduce by binary fission
• Simultaneously heterotrophic and autotrophic

20
Alveolates

• Contain alveoli, membranous sacs below the PM
• Dinoflagellates
• Red tide blooms
• Toxins kill fish and can affect humans
• Ciliates
• Cilia to move and feed
• 2 types of nuclei, 1 for daily activities
  (single, large) and 1 (many, small) for
  reproduction
• E.g Paramecium or Stentor
• Apicomplexans
• Animal parasites
• E.g Plasmodium (malaria)

21
Stramenopiles

• Have hairy and smooth flagella
• Water molds
• Decomposers in moist environments
• May be parasitic (Ireland potato famine)
• Diatoms
• Cell wall of silica
• Fresh and marine organism food source
• Diatomaceous earth
• Brown algae
• Autotrophic
• Kelp

22
Amoebozoans

• Use pseudopodia for movement and feeding
• Free-living amoebas
• Parasitic types
• E.g. amoebic dysentery
• Slime molds
• Organisms found in moist, decaying matter
• Spread under favorable conditions, form spore
  producing structures under less favorable ones
• Plasmodial slime molds are brightly colored
• Single-celled plasmodium
• Cell cycle research
• Cellular slime molds solitary until food is
  scarce
• Cell differentiation research

23
Foraminiferans and Radiolarians

• Move and feed by thread like psuedopodia
• Forams
• Marine and fresh water organisms
• Pseudopodia extend through tests of calcium
  carbonate
• Radiolarians
• Marine
• Internal silica shell and organic outer test

24
Land Plant Relatives

• Red algae
• Carrageenan stabilizes yogurt, chocolate milk,
  and pudding
• Nori in sushi
• Agar for medium plates
• Green algae
• Volvox, colonial hollow balls composed of 100s
  of biflagellated cells