docKingdom: Protista • Endosymbiosis • Classifying Protists • General
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Kingdom: Protista • Endosymbiosis • Classifying Protists • General
Outline: Kingdom Protista Kingdom: Protista • • • • Chapter 28 Endosymbiosis Classifying Protists General Biology of Protists Six Lineages & 15 Phyla – Euglenozoa – Alveolata – Stramenopila – Rhodophyta – Chlorophyta – Choanoflagellida …and… Amoebas Radiolarians Foraminiferans Slime Molds General Biology of Protists The first eukaryote? Cell Organization Eukaryotic, Unicells, Colonials and Multicellular Cell surface Plasma membrane – always Pelomyxa palustris – amoeba-like ancient protist Extracellular Material (“wall”)…chitin, cellulose, silica Some don’t move Locomotion Some move….pseudopodia, flagella, cilia Cyst formation …..Cell Metabolism shuts down ….. Protects Cell from adverse conditions Dormancy Fairmead pond in Epping Forest Photoautotrophs Nutrition Heterotrophs….phagotrophs & osmotrophs Asexual….. mitosis and cytokinesis ….. Binary fission (equal halves) Reproduction ….. Budding (unequal division) ….. Schizogony – many nuclear divisions… several cells Sexual ….. Meiosis 1. Internal membranes like eukaryotes 2. Nuclei 1- many 3. Nuclear mitosis …Nucleus pinches in two 4. NO mitochondria… but Æ Symbiotic bacteria live in cytoplasm 5. Resembles Archaebacteria fiEukaryotes evolved from Archaebacteria ?? Fig. 28.3(TE Art) Endosymbiosis Ancestral eukaryotic cell & internal membrane system Chloroplast Aerobic bacterium Photosynthetic Bacterium Overview of Protist Classification Eukaryotic cell with mitochondrion Mitochondrion Protista ia er ct a ab ia ae er rch t c Ba A ts an gi Pl un F i An m s al Photosynthetic organisms Eukaryotic cell with chloroplasts Eukaryotic Cell 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brown algae Diatoms Oomycetes Eu g Red Algae Green Algae an o fla ge lli da Protist Classification Lineage: Euglenozoa ho Dinoflagellates Apicomplexes Ciliates le no zo a Al ve ol at a St ra m en op il a R ho do ph yt C a hl or op hy ta Euglenoids Kinetoplastids C Fig. 28.4(TE Art) Choanoflagellates Amoebas Forams Slime Molds Euglenoids Kinetoplastids Six Protist Monophyletic (?) Lineages Lineage Euglenozoa: Euglenoids Euglenozoa: Euglenoids – 40 genera, single-celled, mostly freshwater – 1/3 photoautotrophic, 2/3 heterotrophic – Motile – Move by flagella EM views of pellicle Euglenozoa: Kinetoplastids Kinetoplastid Characteristics Genus: Trypanosoma Kinetoplastid (mitochondrion) Kinetoplast in mitochondrion Kinetoplast = One mitochondrion per cell –Mitochondrion extends full length of cell –Mitochondrial genome = kinetoplast –Kinetoplast DNA Maxicircles 50 per cell 15 & 80 Kbp Minicircles 10,000 per cell 0.9 & 2.5 Kbp Function:Rapid glycolysis DNA editing by RNA Kinetoplast Kinetoplast minicircles 2 Diseases caused by Trypanosomes 1. Sleeping sickness, leishmaniasis & Chagas’ disease 2. > 4 million affected annually 3. Control difficult: 2000 variable cell membrane glycoprotein genes Diseases caused by Trypanosomes – Leishmaniasis 1. tropical/subtropical: 88 countries 2. 2 million infections cutaneous visceral (internal organs) 3. Vector Æ sand fly Macrophage filled with leishmania trypanosomes Diseases caused by Trypanosomes – Chagas’ Disease Sand fly vector Protist Classification 1. Disease agent = Trypanosoma cruzi 2. Vector Æ Kissing bug & blood transfusions 3. 30 million people infected (Central & South America) 4. Symtoms: acute: swollen eye, fever, fatigue, organ involvement, brain swelling chronic: 10-20 yrs later weakened cardiac muscle megacolon Dinoflagellates Apicomplexans Ciliates Kissing bug Early infection Infected muscle 16 Alveolata: Dinoflagellates Alveolata: Dinoflagellates Ceratium – A planktonic ¾Alveolus = flattened vesicle below plasma membrane dinoflagellate ¾Single-celled, 2 flagella in grooves 2100 species mostly marine symbiotic dinoflagellates Cellulose plates, maybe some silica ¾Nutrition – about 50% autotrophic Anemone Zooxanthellae ¾Cell Wall – sometimes present alveolus Chloroplasts with 3 membranes Chlorophyll a, c Carotenoids: fucoxanthin ¾Chromosomes Coral No histones with DNA Attached to Nuclear Membrane Condensed throughout interphase ¾Importance (autotrophs) 40% global productivity Zooxanthellae Red tides Bioluminescence jellyfish Spotted jellyfish with zooxanthellae Bleached coral lacking zooxanthellae 3 Alveolata: Dinoflagellates Dinoflagellate blooms = red tides Pfeisteria bloom Noctiluca bloom Æ saxotoxin Na+ channel blocker Noctiluca cells Alveolata: Dinoflagellates Bioluminescence in Pyrodinium bahamense Protist Classification Dinoflagellates Apicomplexans Ciliates Group: Alveolata Apicomplexes Example: Plasmodium • Api = apical • complexa = complex Group: Alveolata – Apicomplexes Plasmodium & Malaria • Apical end of cell Æ complex mass of organelles… – Microtubules – Fibrils – Vacuoles • All parasites of animals • Unicells • Nonmotile Animation of Plasmodium Life Cycle 4 Group: Alveolata Apicomplexes Plasmodium & Malaria Group: Alveolata Apicomplexes Plasmodium Æ Malaria Occurrence: 500 million people infected globally 1 billion people at risk 2 million deaths annually CLINICAL PICTURE: Trophozoite ring stage Merozoites released from red blood cell • • • • • • • Cyclical chills & Fever Incubation period: days to years Headache, enlarged spleen Adult respiratory distress syndrome Severe hemolysis Renal failure Incubation: Days to Years Gametocyte Group: Alveolata Ciliates Example:Paramecium Protist Classification • • • • • • 8000 species Heterotrophic…but… Unicellular Many Cilia Pellicle = flexible covering Gullet = cytostome Dinoflagellates Apicomplexans Ciliates P. bursaria with endosymbiotic alga Group: Alveolata Ciliates Example:Paramecium Group: Alveolata Ciliates Example:Paramecium •Vacuoles – Two types Food Contractile •Nuclei – two Micronucleus Macronucleus Video of contractile vacuole 5 Group: Alveolata Ciliates Example:Paramecium Fig. 35.22a Group: Alveolata Ciliates Example: Paramecium Reproduction ¾ Asexual reproduction mitosis & cytokinesis Sexual reproduction 1. different mating types fuse 2. meiosis of micronuclei 3. 3 of 4 degenerate 4. remaining micronuclei divide mitotically 5. micronuclei exchange 6. fuse to form diploid micronuclei Trichocysts Protist Classification Summary of Protists Examined Thus Far • Group: Euglenozoa • Euglenoids • Kinetoplastids Euglena Trypanosoma • Group: Alveolata • Dinoflagellates • Apicomplexes • Ciliates photosynthetic plankton Plasmodium Paramecium Brown Algae Diatoms Water molds Group Stramenopila – Brown Algae Group Stramenopila –Characteristics 1. Flagella: Lateral & heterokont 1. Tinsel type has mastigonemes 2. Whiplash – no hairs 2. Cell wall: cellulose 3. Nutrition: Autotrophs & Heterotrophs 1. Autotroph chloroplasts 1. chlorophyll a and c 2. carotenoid pigments = fucoxanthin 4. Three groups 1. Brown algae 2. Diatoms 3. Oomycetes = water molds Brown algae epiphytes Live video feed Video Link Kelp 6 Group Stramenopila Group Stramenopila – Brown Algae Macrocystis Brown Algae Æ Kelp Stramenopila – Brown Algae Intertidal habitat Stramenopila Brown Algae Ecological Importance Stramenopila Brown Algae Sargasso sea – a Kelp-dominated ecosystem Brown algae Economic Importance Additives Stabilizers Binding agents Food Kombu Sargassum 7 Group Stramenopila Protist Classification Diatoms ¾Single-celled, 11,000 species 50% marine ¾Cell Wall: Silica ¾Autotrophic ¾Pigments Chlorophyll a, c Carotenoids Fucoxanthin ¾Food reserve Chrysolaminarin Oils Brown Algae ¾Importance Diatoms 40% global productivity Abrasives & filter aids Oomycetes Centric Group Stramenopila Diatoms Silica shells & Symmetry SeaWiFS Satellite Imagery Chlorophyll & Phytoplankton Pennate Diatom Commercial Applications Protist Classification Dynamite Brown Algae Diatoms Oomycetes = Water Molds Filter 8 Group Stramenopila: Oomycetes Water molds & downy mildews Group Stramenopila Oomycetes Reproduction in Saprolegnia – a water mold 9Heterotrophic Protists 9Aquatic: Fresh or salt water 9Terrestrial: Soil 9Parasitic or saprotrophic 9Hypha & Hyphae 9Cellulosic walls Vegetative hyphae Sexual reproduction Asexual reproduction Group Stramenopila Oomycetes Group Stramenopila Oomycetes Saprolegnia (water mold) Phytophthora Plasmopara (downy mildew) Irish Potato Famine & Late Blight 1845-49 1 million deaths Late 1900’s 1.1 million emigrated Protist Classification Ch oa no fla ge yt a lo ro p Ch Plants Fungi lli da Green algae hy ta Red algae Rh od op h m en St ra ata Al ve ol Eu gl en oz o a op il a Euglenoids Dinoflagellates Brown algae Diatoms Kinetoplastids Apicomplexes Oomycetes Ciliates Animals 9 ¾Size: Microscopic to macrophytes Rhodophyta Red Algae ¾Distribution: 98% marine – 7000sp Rhodophyta Red algae Morphology ¾Locomotion: None Porphyridium ¾Pigments: chlorophyll a Phycocyanin & phycoerythrin ¾Storage material: Floridean Starch and mannitol Halosaccion Palmaria palmata (dulse) ¾Cell Wall: Cellulose & biocolloids ¾Importance: Producer organisms Marine Environments Antithamnion Porphyra (nori) Lophophora – encrusting red alga Phylum: Rhodophyta Economic Importance Mastophora – lamellate red alga Protist Classification Ch oa no fla ge yt a lo ro p Ch Plants Fungi lli da Green algae hy ta Red algae Rh od op h m en ata Al ve ol Eu gl en oz o a op il a Euglenoids Dinoflagellates Brown algae Diatoms Kinetoplastids Apicomplexes Oomycetes Ciliates St ra Rhodophyta Ecological Importance Himantothallus in Antarctica Lithothamnion Animals 10 ¾ Size and habit of growth 7000 species, mostly fresh water Enormous diversity Chlorophyta Morphology Chlorophyta Green Algae Unicells Colonial Filamentous ¾ Pigments: Chlorophyll a, b Carotenoids ¾ Storage material Branched, filamentous Starch ¾ Cell Wall Cellulose & pectins Membranous Complex ¾ Locomotion: Many have flagellated stage Chlorophyta Freshwater Habitat Chlorophyta Snowfield Habitat Chlorophyta: Importance 1. Producer organisms 2. Food? Chlorella …a place in space 3. Sewage treatment Scenedesmus …accumulates nitrates & phosphates Chlamydomonas Autotrophic Protists – Green algae 4. Fuel? 11 Protist Classification Green algae Choanoflagellates • • • • • • Plants Fungi lli Ch oa no fla ge Ch lo ro p yt a hy ta da Red algae Rh od op h m en St ra ata Al ve ol Eu gl en oz o a op il a Euglenoids Dinoflagellates Brown algae Kinetoplastids Apicomplexes Diatoms Ciliates Oomycetes Choanoflagellida - Choanoflagellates Animals Heterotrophic protists Colonial forms Single emergent flagellum Collar – strains bacteria Closely related to sponges … and animals Protists - Amoebas Other Protists • Amoebas, Radiolarians & Foraminiferans • Slime Molds • • • • • No permanent locomotor apparatus Amorphous Move by pseudopodia No cell walls No meiosis Entamoeba histolytica Amoeboid Protists - Radiolarians Amoeboid Protists - Radiolarians • Marine planktonic amoebas • Test - glassy silica exoskeletons • Planktonic – mostly warm, equatorial waters Actinoma Actinosphaerium 12 Amoeboid Protists - Radiolarians Axopodia Needle-like podia Extrude out of pores Protists – Foraminiferans •Heterotrophic Marine protists •Planktonic or Bottom Dwellers •Shell = test •Organic material + CaCO3 •Multichambered •Podia emerge from test •Swimming •Gathering •Feeding •Great Fossil Record Radiolarians Cretaceous extinction Fossil forams and mass extinction K/T boundary Post-impact tertiary forams. 1cm above K/T layer Pre-impact Cretaceous (fossil) forams. 2 cm below the K/T layer Foram Sand Beach Foraminifera White Cliffs of Dover Fossil forams Recent Forams 13 Protists: Slime Molds Example: Physarum Slime mold sporangia •500 species •Heterotrophic Protists •plasmodium •Multinucleate •Amoeboid like streaming of cytoplasm Fig. 35.27 Plants Fungi Ch oa no fl a ge lli da Rh od op hy ta Ch lo ro ph yt a ol ata ra m St Al ve Eu gl en oz o a en op ila Protist Classification Animals Amoebas Radiolarians Foraminiferans Slime Molds ? Ancestral Eukaryote END END Protists Multicellular Algae 14