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Chapter 28
Kingdom: Protista• Endosymbiosis• Classifying Protists• General Biology of Protists• Six Lineages & 15 Phyla
– Euglenozoa– Alveolata– Stramenopila– Rhodophyta– Chlorophyta– Choanoflagellida
Outline: Kingdom Protista
…and…AmoebasRadiolariansForaminiferansSlime Molds
General Biology of Protists
Reproduction
Nutrition
Dormancy
Locomotion
Cell surface
Cell Organization Eukaryotic, Unicells, Colonials and Multicellular
Extracellular Material (“wall”)…chitin, cellulose, silica
Plasma membrane – always
Some move….pseudopodia, flagella, cilia
Some don’t move
Cyst formation …..Cell Metabolism shuts down….. Protects Cell from adverse conditions
Heterotrophs….phagotrophs & osmotrophs
Photoautotrophs
Sexual ….. Meiosis ….. Schizogony – many nuclear divisions… several cells ….. Budding (unequal division) ….. Binary fission (equal halves)
Asexual….. mitosis and cytokinesis
The first eukaryote?Pelomyxa palustris –
amoeba-like ancient protist
1. Internal membranes like eukaryotes2. Nuclei 1- many3. Nuclear mitosis …Nucleus pinches in two4. NO mitochondria… but
Symbiotic bacteria live in cytoplasm5. Resembles Archaebacteria
fiEukaryotes evolved from Archaebacteria ??
Fairmead pond in Epping Forest
Ancestral eukaryotic cell & internal membrane system
Eukaryotic cell withmitochondrion
Mitochondrion
Fig. 28.3(TE Art)
Endosymbiosis
PhotosyntheticBacterium
Aerobicbacterium
Eukaryotic cell with chloroplasts
Chloroplast
Photosynthetic organisms
Overview of Protist Classification
Bacteria
Animals
FungiPlants
Archaea
bacteria
Protista
Eukaryotic Cell
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Fig. 28.4(TE Art)
Euglenozo
a
EuglenoidsKinetoplastids
Alveolat
a
DinoflagellatesApicomplexes
Ciliates
Stramen
opila
Brown algaeDiatoms
Oomycetes
Rhodophyta
Red Algae
Choanofla
gellida
ChoanoflagellatesAmoebasForams
Slime Molds
Six Protist Monophyletic (?) Lineages
Chlorophyta
Green Algae
EuglenoidsKinetoplastids
Protist ClassificationLineage: Euglenozoa
Lineage Euglenozoa: Euglenoids
– 40 genera, single-celled, mostly freshwater– 1/3 photoautotrophic, 2/3 heterotrophic– Motile – Move by flagella
Euglenozoa: Euglenoids
EM views of pellicle
Euglenozoa: Kinetoplastids
Genus: Trypanosoma
Kinetoplast in mitochondrion
Kinetoplastid(mitochondrion)
Kinetoplastid CharacteristicsKinetoplast = One mitochondrion per cell
–Mitochondrion extends full length of cell–Mitochondrial genome = kinetoplast–Kinetoplast DNA
Maxicircles 50 per cell15 & 80 Kbp
Minicircles 10,000 per cell0.9 & 2.5 Kbp
Function:Rapid glycolysisDNA editing by RNA
Kinetoplastminicircles
Kinetoplast
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Diseases caused by Trypanosomes1. Sleeping sickness, leishmaniasis & Chagas’ disease2. > 4 million affected annually3. Control difficult:
2000 variable cell membrane glycoprotein genes
Macrophage filledwith leishmania trypanosomes
Diseases caused by Trypanosomes – Leishmaniasis
1. tropical/subtropical: 88 countries2. 2 million infections
cutaneousvisceral (internal organs)
3. Vector sand fly
Sand fly vector
Diseases caused by Trypanosomes – Chagas’ Disease1. Disease agent = Trypanosoma cruzi2. Vector Kissing bug & blood transfusions3. 30 million people infected (Central & South America)4. Symtoms: acute: swollen eye, fever, fatigue, organ
involvement, brain swellingchronic: 10-20 yrs later
weakened cardiac musclemegacolon
Kissing bug Early infection Infected muscle16
Protist Classification
DinoflagellatesApicomplexansCiliates
Alveolata: DinoflagellatesAlveolus = flattened vesicle below
plasma membraneSingle-celled, 2 flagella in grooves
2100 species mostly marine
Cell Wall – sometimes presentCellulose plates, maybe some silica
Nutrition – about 50% autotrophicChloroplasts with 3 membranesChlorophyll a, c Carotenoids: fucoxanthin
ChromosomesNo histones with DNAAttached to Nuclear Membrane Condensed throughout interphase
Importance (autotrophs)40% global productivityZooxanthellaeRed tidesBioluminescence
alveolus
Alveolata: Dinoflagellates
jellyfish
Anemone
Coral
Zooxanthellaesymbiotic dinoflagellates
Ceratium – A planktonicdinoflagellate
Spotted jellyfish with zooxanthellae Bleached coral lacking zooxanthellae
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Alveolata: DinoflagellatesDinoflagellate blooms = red tides
Pfeisteria bloomNoctiluca bloom saxotoxin
Na+ channel blocker
Noctiluca cells
Alveolata: DinoflagellatesBioluminescence in Pyrodinium bahamense Protist Classification
DinoflagellatesApicomplexans
Ciliates
Group: AlveolataApicomplexesExample: Plasmodium
• Api = apical • complexa = complex• Apical end of cell complex
mass of organelles…– Microtubules– Fibrils– Vacuoles
• All parasites of animals• Unicells• Nonmotile
Group: Alveolata – ApicomplexesPlasmodium & Malaria
Animation of Plasmodium Life Cycle
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Merozoitesreleased from red blood cell
Trophozoitering stage
Gametocyte
Group: Alveolata ApicomplexesPlasmodium & Malaria
Occurrence: 500 million people infected globally1 billion people at risk2 million deaths annually
CLINICAL PICTURE:• Cyclical chills & Fever• Incubation period: days to years• Headache, enlarged spleen• Adult respiratory distress syndrome• Severe hemolysis• Renal failure• Incubation: Days to Years
Group: Alveolata ApicomplexesPlasmodium Malaria
Protist Classification
DinoflagellatesApicomplexans
Ciliates
• 8000 species• Heterotrophic…but…• Unicellular • Many Cilia • Pellicle = flexible covering• Gullet = cytostome
Group: AlveolataCiliatesExample:Paramecium
P. bursaria with endosymbiotic alga
•Vacuoles – Two typesFoodContractile
•Nuclei – twoMicronucleusMacronucleus
Group: Alveolata CiliatesExample:Paramecium
Video of contractile vacuole
Group: Alveolata CiliatesExample:Paramecium
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Trichocysts
Group: Alveolata CiliatesExample:Paramecium
Fig. 35.22a
Asexual reproductionmitosis & cytokinesis
Sexual reproduction1. different mating types fuse2. meiosis of micronuclei3. 3 of 4 degenerate4. remaining micronuclei divide
mitotically5. micronuclei exchange6. fuse to form diploid micronuclei
Group: Alveolata CiliatesExample: Paramecium Reproduction
Summary of Protists Examined Thus Far
• Group: Euglenozoa• Euglenoids Euglena• Kinetoplastids Trypanosoma
• Group: Alveolata• Dinoflagellates photosynthetic plankton• Apicomplexes Plasmodium• Ciliates Paramecium
Protist Classification
Brown AlgaeDiatoms
Water molds
Group Stramenopila –Characteristics1. Flagella: Lateral & heterokont
1. Tinsel type has mastigonemes2. Whiplash – no hairs
2. Cell wall: cellulose
3. Nutrition: Autotrophs & Heterotrophs1. Autotroph chloroplasts
1. chlorophyll a and c2. carotenoid pigments = fucoxanthin
4. Three groups1.Brown algae2.Diatoms3.Oomycetes = water molds
Group Stramenopila – Brown Algae
Video Link Kelp
Live video feedBrown algae epiphytes
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Group Stramenopila
Brown Algae KelpGroup Stramenopila – Brown Algae Macrocystis
Stramenopila – Brown Algae Intertidal habitat StramenopilaBrown AlgaeEcological Importance
Sargassum
Stramenopila Brown Algae Sargasso sea – a Kelp-dominated ecosystem Brown algae
Economic Importance
Additives Stabilizers
Binding agents
Food Kombu
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Protist Classification
Brown AlgaeDiatoms
Oomycetes
Single-celled, 11,000 species50% marine
Cell Wall: SilicaAutotrophicPigments
Chlorophyll a, c CarotenoidsFucoxanthin
Food reserveChrysolaminarinOils
Importance40% global productivityAbrasives & filter aids
Group Stramenopila Diatoms
Group Stramenopila DiatomsSilica shells & SymmetryCentric
Pennate
SeaWiFS Satellite Imagery Chlorophyll & Phytoplankton
Diatom Commercial Applications
Dynamite
Filter
Protist Classification
Brown AlgaeDiatoms
Oomycetes = Water Molds
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Group Stramenopila: OomycetesWater molds & downy mildews
Heterotrophic ProtistsAquatic: Fresh or salt waterTerrestrial: SoilParasitic or saprotrophicHypha & HyphaeCellulosic walls
Vegetative hyphae
Sexual reproduction
Group Stramenopila OomycetesReproduction in Saprolegnia – a water mold
Asexual reproduction
Group Stramenopila OomycetesSaprolegnia (water mold)
Plasmopara (downy mildew)
Group Stramenopila Oomycetes
Phytophthora
Irish Potato Famine & Late Blight1845-49 1 million deathsLate 1900’s 1.1 million emigrated
Eugl
enoz
oa
Stra
men
opila
Alve
olat
a
PlantsChloro
phyta
Rhodo
phyta
Choan
oflag
ellida
AnimalsFungi
Protist Classification
EuglenoidsKinetoplastids
DinoflagellatesApicomplexes
Ciliates
Brown algaeDiatoms
Oomycetes
Red algae Green algae
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Size: Microscopic to macrophytes
Distribution: 98% marine – 7000sp
Locomotion: None
Pigments: chlorophyll aPhycocyanin & phycoerythrin
Storage material:Floridean Starch and mannitol
Cell Wall: Cellulose & biocolloids
Importance: Producer organismsMarine Environments
RhodophytaRed Algae
LithothamnionPorphyra (nori)Antithamnion
Halosaccion
RhodophytaRed algaeMorphology
Porphyridium
Palmaria palmata (dulse)
RhodophytaEcological ImportanceHimantothallus in Antarctica
Lophophora – encrusting red alga Mastophora – lamellate red alga
Phylum: Rhodophyta Economic Importance
Eugl
enoz
oa
Stra
men
opila
Alve
olat
a
PlantsChloro
phyta
Rhodo
phyta
Choan
oflag
ellida
AnimalsFungi
Protist Classification
EuglenoidsKinetoplastids
DinoflagellatesApicomplexes
Ciliates
Brown algaeDiatoms
Oomycetes
Red algae Green algae
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Size and habit of growth7000 species, mostly fresh waterEnormous diversity
Pigments: Chlorophyll a, bCarotenoids
Storage materialStarch
Cell WallCellulose & pectins
Locomotion: Many have flagellated stage
ChlorophytaGreen Algae
Chlorophyta Morphology
Unicells Filamentous Colonial
Branched, filamentous Membranous
Complex
Chlorophyta Freshwater Habitat
Autotrophic Protists – Green algae
Chlorophyta Snowfield Habitat
Chlamydomonas
Chlorophyta: Importance1.Producer organisms
2.Food? Chlorella …a place in space
3. Sewage treatment Scenedesmus…accumulates nitrates & phosphates
4. Fuel?
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Eugl
enoz
oa
Stra
men
opila
Alve
olat
a
PlantsChloro
phyta
Rhodo
phyta
Choan
oflag
ellida
AnimalsFungi
Protist Classification
EuglenoidsKinetoplastids
DinoflagellatesApicomplexes
Ciliates
Brown algaeDiatoms
Oomycetes
Red algae Green algae Choanoflagellates
Choanoflagellida - Choanoflagellates
• Heterotrophic protists• Colonial forms• Single emergent flagellum• Collar – strains bacteria• Closely related to sponges• … and animals
Other Protists
• Amoebas, Radiolarians & Foraminiferans• Slime Molds
• No permanent locomotor apparatus• Amorphous• Move by pseudopodia• No cell walls• No meiosis
Entamoeba histolytica
Protists - Amoebas
• Marine planktonic amoebas • Test - glassy silica exoskeletons• Planktonic – mostly warm, equatorial waters
Actinoma
Amoeboid Protists - Radiolarians
Actinosphaerium
Amoeboid Protists - Radiolarians
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Amoeboid Protists - RadiolariansAxopodia Needle-like podia Extrude out of pores •Heterotrophic Marine protists
•Planktonic or Bottom Dwellers
•Shell = test•Organic material + CaCO3•Multichambered
•Podia emerge from test•Swimming•Gathering•Feeding
•Great Fossil Record
Protists – Foraminiferans
K/T boundary
RadiolariansCretaceous extinction
Pre-impact Cretaceous (fossil) forams. 2 cm below the K/T layer
Post-impact tertiary forams. 1cm above K/T layer
Fossil forams and mass extinction
White Cliffs of Dover
Fossil forams
Recent Forams
ForaminiferaForam Sand Beach
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Protists: Slime MoldsExample: Physarum
•500 species
•Heterotrophic Protists
•plasmodium
•Multinucleate
•Amoeboid like streaming of cytoplasm
Slime mold sporangia
Fig. 35.27
Eugl
enoz
oa
Stra
men
opila
Alve
olat
a
PlantsChlor
ophy
ta
Rhodo
phyta
Choan
oflag
ellida
AnimalsFungi
Protist Classification
AmoebasRadiolariansForaminiferansSlime Molds
?
Ancestral Eukaryote
END
Multicellular Algae
ENDProtists