Microbiology (Ch.25) : The Protists

List one human and veterinary disease caused by Fornicata and by the Parabasilia

(Fornicata) Giardia intestinalis.- Cause diarrhea (Parabasilia) Tritrichomonas foetus is a cattle parasite and an important cause of spontaneous abortion in these animals.

Protist Super Groups

1) Excavata 2) Amoebozoa 3) Rhizaria 4) Chromalveolata 5) Archaeplastida

Explain the importance of heterokont flagella in the taxonomy of the Stramenophila (Super Group Chromalveolata)

One unifying feature of this very diverse taxon is the possession of heterokont flagella at some point in the life cycle. This is characterized by two flagella—one extending anteriorly and the other posteriorly. These flagella bear small hairs with a unique, three part morphology; the name stramenophila means "straw hair."

Compare and contrast the morphology and function of the micro and macronucleus and trace their fate during ciliate conjugation

The micronucleus contains the diploid chromosomes for sexual reproduction The macronucleus is a polypoid and produces mRNA to maintain cellular metabolism and function

Super Group Excavata Subgroups

a) Fornicata b) Trichomonadida c)Parabasilia d) Euglenozoa

Identify a location near your home or school where you might find a Fornicata, a Parabasilia and a Euglena

Fornicata: Turkey farm Parabasilia: Wooden structures where termites may reside Euglena: Found in freshwater, such as lakes.

Explain the importance of molecular signaling in the morphological development of Dictyostellium discoideum

When starved, cells release cyclic AMP and a specific glycoprotein, which serve as molecular signals. Other cells sense these compounds and respond by forming an aggregate around the signal-producing cells. In this way large, motile, multicellular slugs develop and serve as precursors to fruiting body formation.

Differentiate between a naked and a testate amoeba

Amoebae can lack a cell wall (naked amoebae) or be covered (testae amoebae)

Draw 3 different types of Pseudopodia (Super group Amoebozoa)

Amoeboid motility involves pseudopodia (cell extensions): 1)That are rounded (lobopodia), 2) Long and narrow (filopodia), or 3) Form a mesh (reticulopodia)

List at least 2 diseases caused by the apicomplexans

Apicomplexans are important infectious agents: 1) Eimera: Cecal coccidiosis in chickens 2) Cryptosporidia: Intestinal infection 3) Toxoplasma: Toxoplasmosis from cat feces 4) Theilaria: Tick-borne blood diseases in cattle 5) Plasmodium: MALARIA, a major killer worldwide

Super group Chromalveolata Subcategories

(1) Alveolata a) Dinoflagellates b) Ciliates c) Apicomplexans (2) Stremenophila (3) Haptophyta

Classification of Organisms

1) Domain 2) Kingdom 3) Phylum 4) Class 5) Order 6) Family 7) Genus 8) Species

Review the structure, morphology, reproduction, and ecological importance of Diatoms

1) Photoautotrophs 2) Diatoms form silica shells (frustules) made of two overlapping halves; frustule morphology is diverse and used for identification; can be unicellular, colonial, or filamentous; lack flagella 3) Asexual reproduction occurs until frustule becomes too small and then sexual reproduction occurs where the zygote develops into an auxospore that divides and forms a new wall to produce vegetative cells with frustules 4) Found in aquatic systems; major contributors to carbon fixation in the ocean and vital to global carbon cycles

Describe three nutritional strategies used by protists

1) Photosynthetics protists are aerobes that perform plant-like oxygenic photosynthesis; some are photoheterotrophic 2)Chemoheterotrophis protists are holozoic(phagocytize solid foods such as bacteria) or saprozoic (take up soluble nutrients); 3)Some protists are mixotrophic, having flexible metabolisms (simultaneous photosynthesis and holozoic feeding.

Super Group Rhizaria Subgroups

1) Radiolaria 2) Foraminifera

Discuss the etiology (cause) of Chagas' disease and African sleeeping sickness

1) Trypanosoma cruzi causes Chagas' disease in Central and South America characterized by peripheral nervous dysfunction 2) T. gamiense and T. rhodesiense cause African sleeping sickness

Super Group Amoebozoa Subgroups

1) Tubuline 2) Entamoebida 3) Eumycetozoa

List at least 3 different morphologies found among the Chloroplastida (Super Group Archaeplastida)

1. Commonly called green algae, these phototrophs are found in aquatic and soil systems; many cell types including unicellular, filamentous, and colonial 2. Have chlorophylls a and b and carotenoids; store carbohydrates as starch 3. Asexual reproduction is through zoospores and sexual reproduction involves four flagellated zygotes and resting phase with meiosis, producing haploid organisms 4. Chlamydomonas is highly studied; has two flagella, a haploid nucleus, a giant chloroplast, contractile vacuoles, and a stigma (eyespot) 5. Protheca is common in soil and can cause severe subcutaneous and systemic blood infections (protothecosis) in animals and humans

Identify the unique structures found in an apicomplexan cell and explain their function

Acomplexa are intra- and intercellular parasites of animals with a unique array of cytoskeleton, vacuoles, and other organelles at one end of the cell the apical complex designed to penetrate host cells; some have motile gametes or zygotes Apical complex includes apicoplasts, endosymbiotic organelles for the synthesis of lipids and heme

Outline the apicomplexan life cycle

Complex life cycle has sexual and asexual stages that sometimes occur in different hosts; the motile haploid infective stage is called the sporozoite; in the host, gamonts are generated, which fuse to form zygotes that become spores; these undergo meiosis to generate more haploid sporozoites.

Cellular Slime Molds

Dictyostelium discoideum is the classic cellular slime mold a) Masses called pseudoplasmodium retain their cells walls; under adverse conditions cells aggregate into motile multicellular slugs that form fruiting bodies with spores that can germinate into amoeboid cells b) Cells can diffferentiate into what resemble primitive immune cells (sentinel cells) that patrol for pathogens c) Sexual reproduction involves special spores called macrocysts that arise via conjugation

Explain the importance of dinoflagellates to coral biology and the generation of "red tides"

Dinoflagellata - Large group of common marine plankton, involved in coral formation; the causative agents of toxic red tides

Describe the morphology, motility and feeding behaviors of Dinoflagellates (Super group Chromalveolata, Sub Group Alveolata)

Dinoflagellates 1) Many are photosynthetic but not autotrophic; most are saprotrophic, but some use endocytosis 2) Some flagella cause the cells to whirl; thecate (Being contained in a theca) cells are armored with cellulose plates 3) Most are free living, but some are endosymbionts that release motile cells called zooxanthellae

Diagram how a ciliate captures a food particle and consumes it

Employ many cilia for movement and feeding; the action of cilia is coordinated; some have tentacles or expel poison darts (toxicysts) to capture prey. Food first enters the cytosome and passes into phagocytic vacuoles that fuse with lysosomes after detachment from the cytosome. The ciliate digests the vacuole's contents when the vacuole is acidified and lysosomes release digestive enzymes into it. After the digested material has been absorbed into the cytoplasm, the vacuole fuses with the cytoproct and waste material is expelled.

Explain the morphology, motility, and feeding mechanisms and reproduction of members of Foraminifera (Super group Rhizaria)

Foraminifera 1) Amoeboid with reticulopodia and form calcerous shells; can have algal symbionts 2) Complex life cycles that may alternate between asexual and sexual phases; the sexual phase includes flagellated gametes and haploid gamonts; autogamy is known 3) They are found in marine and estuarine waters and most are benthic; some may be capable of dentrification; their calcerous shells accumulate on the sea floor creating chalk, limestone, and marble layers hundreds of meters deep

Inferr why the accreation of foraminiferan tests occur and why it is important in oil exploration

Foraminiferintests accumulate on the sea floor where they constitute a fossil record dating back to the Early Cambrian (543 million years ago), which is helpful in oil exploration. if the species in question is extinct, then one examines modern forms, inferring that the fossil forms had similar environmental preferences. In the latter case, studies of the rock containing the fossils (sandstone, shale, limestone, etc.) give further clues to the environment of deposition.

Describe the structure and life cycle of the model organism, Chlamydomonas (Super Group Archaeplastida, Sub Group Chloroplastida)

Has two flagella, a haploid nucleus, a giant chloroplast, contractile vacuoles, and a stigma (eyespot)

Describe the morphology of the filopodia and axopodia found in members of Rhizania.

Morphololgically, the Rhizaria can be distinguished by their fine pseudopodia (filopodia), which can be simple, branched, or connected. Filopodia supported by microtubules are known as an axopodia. Protrude from an axoplast and are used for feeding

Acellular Slime Molds

Myxogastria are acellular slime molds that live in amoeboid fashion, feeding by endocytosis; under adverse conditions, fruiting bodies form with stalks and spores; spores germinate to produce haploid amoeboflagellates and eventually zygotes and new plasmodium

Explain how contractile vacuoles are used to maintain osmotic stability

Osmotic stability is maintain by continuous water expulsion. (hypotonic environments , such as freshwater lakes)

Draw a typical protist cell membrane and underlying features, labeling the plamalemma, ecto- and endoplasma, and pellicle.

Plasmalemma (Cell membrane) Cytoplasm can be divided into: a)Ectoplasm: gelatinous outermost region; and B) Endoplasm: inner liquid Pellicle: Is a rigid layer coated by the plasmalemma that acts as a supportive structure.

Explain the morphology, motility, and feeding mechanisms and reproduction of members of Radiolaria (Super group Rhizaria)

Radiolaria Most radiolaria have internal skeletons of siliceous material or strontium sulfate; some have siliceous exoskeletons, while others lack skeletons 2) Feed by endocytosis via entrapment in mucous; some by algal endosymbionts 3) Reproduction can be sexual with release of many biciliated isogametic cells or asexual by binary or multiple fission or budding

Compare and contrast the structure, motility, and life cycles of acellular and cellular slime molds (Subgroup Eumycetozoa)

Slime molds have complex morphology, life cycle, and behavior. 1)Myxogastria are acellular slime molds that live in amoeboid fashion 2)Dictyostelium discoideum is the classic cellular slime mold

Draw a typical EUGLENA cell and explain the function of the stigma and pyrenoid

Stigma: Giant eye spot for orientation to light Pyrenoid: The function of the pyrenoid in euglena is to produce and supply starch.

Identify which member of EXCAVATA (supergroup) have hydrogenosomes

TRICHOMONADIDA Anaerobic; do not contain mitochondria, but have hydrogenosomes, and reproduce asexually. Symbionts of digestive, reproductive, and respiratory tracts of vertebrates. I)Tritrichomonas foetus can cause spontaneous abortion in cattle. II)Dientamoeba fragilis causes diarrhea in humans III)Trichonomas vaginalis can cause disease in human genitourinary tract