Chapter 12
Eukaryotic organisms
• Mycology – study of fungi
• Heterotroph
• Absorb nutrients
• Yeasts – unicellular
• Molds – multicellular, filamentous
• Filaments – hyphae
• Fragment hypha can grow into a fungus
Aerial hyphae – reproductive sporesVegetative hyphae – absorb nutrientsCottony, fluffy
• Yeasts – unicellular
• Oval or circular in shape
• Many reproduce by budding
• Buds fail to separate from the parent
• Pseudohyphae are formed
• Candida albicans
Dimorphic fungi
• Mold-like - 25o C
• Yeast-like – 37oC
• Many fungi make asexual spores
• Different types of asexual spores
Septate hyphae – fragmentsSingle cells - Thick cell wallsCoccidiodes immitis
Pseudohypha – round and enlarged
Candida albicans
Rhizopus
Conidiospores - Penicillium
Sexual reproduction
• Two different strains• + and –• Pheromones - proteins• Attract negative strain – mate• + and - fuse to make zygote• Differentiates into a sexual spore• Environmental conditions• Nutrient depletion
Three groups of fungi
• Based on sexual spores
• Zygomycota
• Asexual spores – sporangiospores
• Sexual spores – zygospores
• Coenocytic hyphae
• Rhizopus
Ascomycota
• Some molds and some yeasts
• Molds – septate hyphae
• Asexual spores – conidiospores
• Yeasts reproduce by budding
• Sexual spores – ascospores
• Penicillium
Basidiomycota
• Mushrooms
• Septate hyphae
• Asexual – fragmentation of hyphae
• Sexual spores - basidiospores
Mycoses – fungal diseases
• Systemic mycoses – deep within the body
• Inhaling fungal spores
• Starts in the lungs – spreads to other parts
• Histoplasmosis – Histoplasma capsulatum
• Dimorphic fungus
• Conidiospores
• Soil enriched with bird droppings
• Minor respiratory infection
• Immune system is weak – spreads to liver, spleen, bone marrow
• Coccidioidomycosis – Coccidiodes immitis
• Arthrospores – soil – southwest – abundant in the soil
• Cough, Chest pain
• Amphotericin B
• Cutaneous mycosis – hair, nail, skin
• Ringworm, tineas
• Fungi – dermatophytes
• Keratinase – breaks down keratin
• Tinea pedis – athlete's foot
• Trichophyton rubrum
• Itching, scaling skin
• Direct contact, shower room floors
Opportunistic mycosis
• Candidiasis
• Candida albicans
• Normal flora
• Immune system weak
• Thrush – Candida infection of the oral cavity
• AIDS, newborns
Amanita phalloides
• Mushroom
• Death angel
• Neurotoxin
• Hallucinations
• Death within a week due to liver damage.
Claviceps purpurea
• Grows on grains – rye
• Toxin – ergot
• Ergotism
• Hallucination
• Constriction of the capillaries – gangrene
• Middle ages
Protozoa
• Unicellular – eukaryotic
• Soil, water, within the bodies of humans and animals.
• Trophozoites – metabolically active, reproduce, motile, inside the host
• Cyst – metabolically inactive, dormant, outside the host.
Entamoeba histolytica
• Pseudopods• Intestinal tract• Cysts are released in the feces.• Contaminated food or water.• Cysts – trophozoites – intestinal tract• Feed on cells lining the intestinal tract, red
blood cells.• Dysentery – bloody diarrhea
Giardia lamblia
• Flagella
• Intestinal tract – carriers
• Cysts are released in the feces
• Trophozoits attach themselves to intestinal wall
• Abdominal pain, diarrhea, weight loss
• Metronidazole
Balantidium coli
• Cilia for movement.
• Macronucleus - controls protein synthesis
• Micronucleus – transmits genetic information
• Cysts are transmitted in contaminated food or water
Hemoflagellates
• Long, slender body• Undulating (wavy) membrane• Flagellum• Trypanoasoma gambiense• African sleeping sickness• transmitted by tsetse fly• Grows in the bloodstream• Causes damage to the nervous system• Drowsiness, coma, death
Trypanosoma cruzi
• Kissing bug
• Bug lives in the cracks and crevices of mud huts.
• Mexico, South America
• Damage to the nerves
• Chagas disease
• Mega colon, mega esophagus
Kinetoplast
Mitochondrial DNA
flagellum
Plasmodium
• Malaria
• Mosquito
• Chills, fever, vomiting
• Complex lifecycle
• Chloroquine
Algae
Store energy –form petroleum diatoms
Dinoflagellates
• Plankton – free floating
• Aquatic environments – oceans
• Alexandrium – neurotoxin
• Mollusks – clams – eat a large amount of dinoflagellates - toxin is concentrated in clams
• People eat these clams – paralytic shellfish poisoning
• Numbness of the mouth and lips
• Heat stable
• Ocean has a red tide
Helminths
• Worms• Multicellular• Eukaryotic• Animal kingdom• Do not have a well developed nervous system or
digestive system.• Do have a complex reproductive system.• Platyhelminthes (flatworms) and nematodes
(round worms)
Platyhelminthes
• Trematodes (flukes)• Cestodes (tapeworms)• Trematodes• Flat leaf like body• Hermaphroditic ( have both male and female
reproductive organs – testes and ovaries)• Intermediate host – immature worm (larvae),
asexual reproduction• Definitive host – mature worm (adult), sexual
reproduction
Paragonimus westermani
• Lung fluke
• Bronchioles of infected humans and other animals.
• 12 mm long ( lives for 4 to 5 years)
• Chest pain, cough
• Praziquantel
Cestodes
• Intestinal parasites
• Head – scolex
• Scolex – hooks and suckers – attachment to the host.
• Segmented body
• Segments – proglottids
• Hermaphroditic
Taenia saginata – beef tapeworm
• Adult – human intestinal tract
• Eggs are released in the feces
• Cattle –ingest
• Larvae – cysts in the muscles (cysticerci)
• Transmitted to humans – undercooked contaminated beef.
• Intestinal tract – scolex comes out – develops into an adult worm.
• 18 feet
• 25 years
• Presence of eggs in the feces
• Abdominal discomfort
• Niclosamide
Taenia solium
• Adult – infected humans (definitive host)
• Eggs – feces
• Ingested by pigs ( intermediate host)
• Larvae - cysts in the muscles
• Undercooked contaminated pork
• More dangerous – humans can also become intermediate hosts.
• Eggs can be ingested by humans
• Larvae form cysts in the muscles, brain
• Neurocysticercosis – “swiss cheese”
• Headache , convulsions, coma , death
• Poor sanitary practices
• Mexico, South America
Echinococcus granulosus
• Definitive host – dogs coyotes
• Eggs – feces
• Humans – poor sanitary practices
• Larvae – cysts – liver – lungs
• Cysts – hydatid cysts
• Humans – dead end – life cycle of the worm
Sheep herding population
Nematodes (roundworms)
• Dioecious – male and female worms.
• Enterobious vermicularis (pinworm)
• Intestine - female migrates to the anus
• Releases eggs – perianal area
• Itching in the area
• Mebendazole
Ascaris lumbricides
• Small intestine
• Feed on semidigested food
• eggs – feces
• Larvae – intestinal tract – migrate to the lungs – go back to the intestine – adult
• Obstruction of the intestinal tract
Necator americanus
• Intestinal tract
• Eggs –feces
• Larvae come out in the soil
• Penetrates the skin – intestinal tract
• Attaches to the intestinal wall – drink blood
• Anemia
• Prevention – wear shoes
Trichinella spiralis
• Undercooked encysted pork – larvae come out in the intestinal tract
• Female releases larvae
• Larvae form cysts in the muscles
• Diaphragm muscle
• Pigs – eating contaminated pork