The Eukaryotes: Fungi, Algae, Protozoa, and Helminths 12 The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

Eukaryotes Over ½ world’s population infected w/eukaryotic pathogens. Malaria, schistomosomiasis, amoebiasis, hookworm, African trypanosomiasis, intestinal parasites Emerging: Pneumocystis- leading cause of death in AIDS patients, Cryptosporidium- 400,000 people in Milwaukee 1993, Cyclospora (new protozoan parasite)

The Fungi Chemoheterotrophic Most are decomposers, important plant decomposer Mycology is the study of fungi Last 10 years fungal infections have increased, nosocomial

Mycology: The Study of Fungi Table 12.2

Fungi Table 12.1

Molds The fungal thallus (body) consists of hyphae (long filaments of cells joined together); a mass of hyphae is a mycelium (visible to unaided eye) Figure 12.2

Yeasts Nonfilamentous, Unicellular fungi Spherical or oval Identified by chemical tests Figure 12.3

Dimorphism Pathogenic dimorphic fungi are yeastlike (reproductive, budding) at 37°C and moldlike (vegetative) at 25°C Figure 12.4

Life Cycle Filamentous can fragment (asexually) Form spores Asexually= formed by hyphae of one individual, germinate into genetically identical organism Conidiospore, sporangiospore Sexually= from the fusion of nuclei from 2 fungi, genetic recombination Plasmogamy, karyogamy, meiosis, zygospores Fungi are identified by their spores.

Nutritional Adaptations Generally adapted to environments hostile to bacteria pH 5 Almost all molds aerobic, yeasts facultative anaerobes Resistant to osmotic pressure, can grow in high sugar/salt Low moisture Less nitrogen Metabolize complex carbohydrates: lignin

Mycosis Fungal infection Chronic or long lasting because fungal grow slowly Drugs that affect fungal may also affect animal cells, often difficult to treat Divided into 5 groups depending on the tissue involvement

Mycosis Systemic- deep within body, usually caused by fungi that live in the soil, inhalation of spores Subcutaneous- beneath skin, directly in skin from soil Cutaneous- epidermis, hair & nails, transmitted by contact of infected hairs (barber, shower) Superficial- hair shaft, surface epidermal, Tropical Opportunistic- host debilitated, antibiotics, immunosupressed (pneumocystis, yeast infection)

Zygomycota Conjugation fungi Produce sporangiospores and zygospores Common black bread mold Rhizopus, Mucor- Compost piles exposure could cause respiratory infection

Ascomycota Sac fungi Molds with Septate hyphae and some yeasts Produce ascospores and frequently conidiospores. Aspergillus (opportunistic, systemic mycosis) Blastomyces dermatitidis, Histoplasma capsulatum (systemic mycoses) inhalation Microsporum, Trichophyton (cutaneous mycoses) Ring worm, athlete’s foot

Basidiomycota Club fungi mushrooms Produce basidiospores and sometimes conidiospores. Cryptococcus neoformans (systematic mycosis) inhalation of soil/bird feces Malassezia- dandruff, dermatitis

Anamorphs Anamorphic fungi (used to be Deuteromycota) Reproduce by asexual spores only. Penicillium Sporothrix (subcutaneous mycosis) puncture wound/soil Stachybotrys, Coccidioides, Pneumocystis (systemic mycoses) inhalation/soil Candida albicans (Cutaneous mycoses) normal human biota

Lichens Mutualistic combination of an alga (or cyanobacterium) and fungus. Alga produces and secretes carbohydrates; fungus provides holdfast. Can live together in locations where neither could survive alone: rocks, exposed soil

Lichens Figure 12.10

The Algae Mostly aquatic: kelp, pond scum, green stains on rocks Unusual place: hair of sloth, polar bear Unicellular, filamentous, or multicellular (thallic), lack tissues (roots, leaves, stems) Most are photoautotrophs

Algae Table 12.1

Algae Figure 12.11a

Phaeophyta Brown algae (kelp) Cellulose and alginic acid cell walls Multicellular Chlorophyll a and c, xanthophylls Store carbohydrates Harvested for algin- thickener in foods Figure 12.11b

Rhodophyta Red algae Cellulose cell walls Most are multicellular Chlorophyll a and d, Store glucose polymer Harvested for agar and carrageenan-thickener Figure 12.11c

Chlorophyta Green algae Cellulose cell walls Unicellular or multicellular Chlorophyll a and b Store glucose polymer Gave rise to plants Figure 12.12a

Bacillariophyta Diatoms Pectin and silica cell walls Unicellular Fossilized diatoms formed oil (Store EN) Produce domoic acid-toxin in mussels Daughter cell retains ½ cell wall from parent Figure 12.13

Dinoflagellata Dinoflagellates “plankton” Cellulose in plasma membrane-rigid structure Unicellular algae Store starch Some are symbionts in marine animals Neurotoxins cause paralytic shellfish poisoning from eating shellfish Red Tide- mollusks should NOT be harvested Figure 12.14

Oomycota Water molds Cellulose cell walls Multicellular Chemoheterotrophic Produce zoospores Decomposers and plant parasites Figure 12.15

The Protozoa Table 12.1

Protozoa Unicellular Chemoheterotrophs Vegetative form is a trophozoite. Asexual reproduction is by Fission, budding, or schizogony. (multiple fission) Sexual reproduction by conjugation. Some produce cysts, during unfavorable conditions. Figure 12.16

Archaezoa No mitochondria- mitosome (remnant of mitochondria) Multiple flagella, symbionts Giardia lamblia- enteritis Trichomonas vaginalis – urethritis, vaginitis Figure 12.17b–d

Microspora No mitochondria Nonmotile Intracellular parasites Reported since 1984 Nosema diarrhea, conjunctivitis

Amoebozoa Move by pseudopods Entamoeba- human intestinal tract causes dysentery Transmitted by Ingesting of cysts Acanthamoeba- Growing in water can infect cornea Figure 12.18a

Apicomplexa Special organelles apexes (tips) w/enzymes that penetrate the host’s tissues Nonmotile in mature forms Intracellular parasites Complex life cycles

Apicomplexa Plasmodium- malaria, world wide Babesia- RBC parasite, fever and anemia Cryptosporidium- Respiratory and gallbladder infections in immunosuppressed Cyclospora- 300 cases of diarrhea associated w/snow peas in US 2004

Plasmodium 2 3 8 7 6 Figure 12.19

Ciliophora (Ciliates) Move by cilia Balantidium coli human parasite, dysentery from contaminated drinking water Figure 12.20

Euglenozoa Move by flagella, simirigid membrane= pellicle Photoautotrophs, but can use cytostome in the dark to ingest food Euglenoids- red “eye” spot Hemoflagellates- blood parasites Naegleria: meningoencephalitis, in swimming water Trypanosoma: transmitted by vectors (bug bite) Chagas disease (kissing bug) or tsetse fly Leishmania: sand fly vector, Leishmaniasis

Euglenozoa Figure 12.21

Slime Molds Have both fungal and amoebal characteristics but are more closely related to amoeba & placed in the phylum Amoebozoa with 2 taxa: Cellular Plasmodial

Slime Molds Cellular slime molds Resemble amoebas, ingest bacteria by phagocytosis. Migrating cells called slugs Cells aggregate into stalked fruiting body. Some cells become spores.

Slime Molds Plasmodial slime molds Exists as protoplasm, Multinucleated large cells which move like amoeba Cytoplasm separates into stalked sporangia to make spores when conditions are harsh Nuclei undergo meiosis and form uninucleate haploid spores which fuse to form diploid

Cellular Slime Mold Figure 12.22

Plasmodial Slime Mold Figure 12.23 (1 of 2)

The Helminths Table 12.1

Helminths (parasitic worms) Highly specialized to live inside hosts May lack digestive system Reduced nervous system Reduced locomotion or lacking Reproductive system is complex

Helminths (Parasitic Worms) pg 378 Eukaryotic, Multicellular animals, Chemoheterotrophic Generally infect the digestive tract Kingdom: Animalia Phylum: Platyhelminthes (flatworms) Class: Trematodes (flukes, flat leaf shaped) Class: Cestodes (tapeworms, suckers) Phylum: Nematodes (roundworms)

Trematodes Figure 12.25

Humans as Definitive Host Figure 12.26

Cestodes Figure 12.27

Humans as Intermediate Host Figure 12.28

Nematodes: Eggs Infective for Humans Figure 12.29

Nematodes: Larvae Infective for Humans Figure 25.26

Arthropods as Vectors pg 378 Kingdom: Animalia Phylum: Arthropoda (exoskeleton, jointed legs) Insecta (6 legs) Lice, fleas, mosquitoes Crustacea (4 antennae) Crabs, crayfish Arachnida (8 legs) Mites and ticks Figures 12.31a, 12.32

Arthropods as Vectors Figure 12.33