The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

Ch 12

. List the defining characteristics of fungi. . Identify two beneficial and two harmful effects of fungi. . List the defining characteristics of protozoa. . Differentiate an intermediate host from a definitive host. . List the distinguishing characteristics of the two classes of parasitic helminths, and give an example of each. . Provide a rationale for the elaborate life cycles of parasitic worms. . Define arthropod vector. . Differentiate between a tick and a mosquito, and name a disease transmitted by each.

Copyright © 2010 Pearson Education, Inc. FUNGI . Chemoheterotroph, aerobic (molds) or facultatively anaerobic (yeasts) . Mycology: Study of fungi . Most fungi decomposers, few are parasites of plants and animals. . # of serious fungal infections increasing

Fig. 12.1

ReviewCopyright © 2010 Table Pearson Education, 12.2 Inc. Characteristics of Fungi . Hyphae: Filaments of cells, mostly septate . Mycelium: Mass of hyphae. . Molds: mostly filamentous. . Yeasts: nonfilamentous, unicellular fungi. . Budding yeasts divide asymmetrically. . Dimorphic fungi: yeasts like 37C, molds 25C. . Fungal spores differ from bacterial spores. Form from aerial hyphae. . Growth in acidic, low-moisture, high osmotic pressure environments.

. Saccharomyces cerevisiae: Bread, wine, HBV vaccine . Trichoderma: Cellulase . Taxomyces: Taxol . Entomophaga: Biocontrol . Paecilomyces: Kills termites

. Mold spoilage

1. Systemic mycosis: infection deep within body, affects many tissues and organs. Histoplasmosis and coccidiomycosis. 2. Subcutaneous mycosis: Saprophytic fungi, e.g.: Sporotrichosis. 3. Cutaneous mycosis = Dermatomycosis: affects keratin-containing tissues (hair, nails, skin). 4. Superficial mycosis: localized on hair shafts and superficial skin cells. Opportunistic mycoses: . caused by normal microbiota or fungi that are not usually pathogenic (E.g.: Candidiasis and Pneumocystis pneumonia) . usually systemic. Copyright © 2010 Pearson Education, Inc. Human eyelash with unknown fungus infection. Minimal damage to skin or underlying tissues. However, impaired IS can encourage the infecting fungus to proliferate.

Copyright © 2010 Pearson Education, Inc. ALGAE Mostly photoautotrophs, mostly in ocean Diatoms . Unicellular, store energy in form of oil . Domoic acid  Neurological disease . Ingestion of mussels that fed on diatomes (also affects birds and sealions) Dinoflagellates (plankton) . Some produce neurotoxins: red tide . Kills fish, marine mammals, and humans, e.g.: parasitic shellfish poisoning (PSP) Copyright © 2010 Pearson Education, Inc. PROTOZOA

Unicellular, eukaryotic chemoheterotrophs. Large and diverse group. Few are pathogenic. Found in soil and water and as normal microbiota in animals. Trophozoite: Vegetative form (feeding and growing). Asexual reproduction via fission, budding, or schizogony (multiple fission). Sexual reproduction via conjugation. Some protozoa can produce a cyst that provides Copyrightprotection © 2010 Pearson Education, Inc. during adverse environmental conditions. Medically Important Protozoa 1. Arcaezoa (lack mitochondria) . Trichomonas and . Giardia 2. Microspora (no mitochondria and no microtubules) – diarrhea and keratoconjunctivitis in AIDS patients 3. Amoebozoa (move via pseudopodia) . Entamoeba (dysentery) and Acanthamoeba 4. Apicomplexa: not mobile, intracellular . Plasmodium, Babesia, Toxoplasma, Cryptosporidium 5. Euglenozoa: Hemoflagellates . Trypanosoma

. Move by pseudopods . Entamoeba . Acanthamoeba

7 6

Fig 12.18 Euglenozoa

. Move by flagella . Hemoflagellates . Trypanosoma spp.  Sleeping sickness  Chagas’ disease

Fig 23..22 Copyright © 2010 Pearson Education, Inc. HELMINTHS (Parasitic Worm) . Kingdom: Animalia . Phylum: Platyhelminthes (flatworms) Class: Trematodes (flukes) Class: Cestodes (tapeworms) . Phylum: Nematoda (roundworms) . few are human parasites . Anatomy and life cycle modified for parasitism . Adult stage in definitive host. . Each larval stage in specific Copyrightintermediate © 2010 Pearson Education, Inc. host. Life Cycle of Helminths

. Monoecious (hermaphroditic) . Male and female reproductive systems in one animal . Dioecious . Separate male and female . Egg  larva(e)  adult

Copyright © 2010 Pearson Education, Inc. Platyhelminths . Dorsoventrally flattened Trematode, or fluke: Oral and ventral sucker attaches to host tissue . Cestode, or tapeworm: Scolex (head), proglottids

4 suckers and rostellum with hooks

Fig 12.26

Gravid proglottid with uterine branches Taenia solium Taenia saginata

Human definitive host;

Fig. 12. 27 Human as Human is ….

Cysticerci in beef Definitive Host Taenia saginata muscle

Echinococcus Intermediate Host Adult in dog granulosus Nematodes Roundworms have a complete digestive system Eggs infective for humans: . . Ascaris lumbricoides: Ascariasis. 2nd most common worm infection in US. (Most common worldwide; > 1 bio infected) . Enterobius vermicularis (pinworm). Most common worm infection in US (30% of children, 16% of adults infected) .

Fig12.28 Copyright © 2010 Pearson Education, Inc. Diagnosing Pinworm Disease Do test immediately after waking up. Several samples pinworm paddle might need to be examined. Since scratching of the anal area is common, samples taken from under the fingernails may also contain eggs. Larvae Infective for Humans Fig 25.23

Hookworms Ancylostoma duodenale and

CopyrightNecator © 2010 Pearson Education,americanus Inc. Trichinellosis: The Life Cycle of Trichinella spiralis The Heartworm Dirofilaria immitis Primarily in dogs and cats  human heart failure, also in human lungs Spread via mosquitoes

Fig 12.29

Copyright © 2010 Pearson Education, Inc. ARTHROPODS AS VECTORS Kingdom: Animalia . Phylum: Arthropoda (exoskeleton, jointed legs, segmented body)  Class: Insecta (6 legs)  Lice, fleas, mosquitoes  Class: Arachnida (8 legs)  Mites and ticks . Arthropods that carry diseases are called vectors. . Elimination of vectorborne diseases best via control or eradication of vectors.

Copyright © 2010 Pearson Education, Inc. Arthropod Vectors . Mechanical transmission . Biological transmission . Microbe multiplies in vector . Definitive host . Microbe’s sexual reproduction in vector Fig 12.32