Fungi, Algae, Protozoa, and Helminths The Eukaryotes

The Fungi Eukaryotic Aerobic or facultatively anaerobic Chemoheterotrophic Most are decomposers Mycology is the study of fungi

Molds The fungal thallus consists of hyphae; a mass of hyphae is a mycelium. Figure 12.2

Yeasts Unicellular fungi Fission yeasts divide symmetrically Budding yeasts divide asymmetrically Figure 12.3

Dimorphism Pathogenic dimorphic fungi are yeastlike at 37°C and moldlike at 25°C Figure 12.4

Fungal Life Cycle Figure 12.7

Fungal Diseases (mycoses) Systemic mycoses Deep within body Subcutaneous mycoses Beneath the skin Cutaneous mycoses Affect hair, skin, nails Superficial mycoses Localized, e.g., hair shafts Opportunistic mycoses Caused by normal microbiota or fungi that are normally

Protozoa Eukaryotic Unicellular Chemoheterotrophs Vegetative form is a trophozoite Asexual reproduction by fission, budding, or schizogony Sexual reproduction by conjugation Some produce cysts Figure 12.16

Archaezoa No mitochondria Multiple flagella Giardia lamblia Trichomonas vaginalis (no cyst stage) Figure 12.17b-d

Apicomplexa Nonmotile Intracellular parasites Complex life cycles Plasmodium Babesia Cryptosporidium Cyclospora

Plasmodium 1 2 9 3 Sexual reproduction Asexual reproduction 8 4 5 7 6 Infected mosquito bites human; sporozoites migrate through bloodstream to liver of human 2 Sporozoites undergo schizogony in liver cell; merozoites are produced Sporozoites in salivary gland 9 Resulting sporozoites migrate to salivary glands of mosquito 3 Merozoites released into bloodsteam from liver may infect new red blood cells Sexual reproduction Asexual reproduction 8 In mosquito’s digestive tract, gametocytes unite to form zygote Zygote Intermediate host Female gametocyte 4 Merozoite develops into ring stage in red blood cell Male gametocyte Ring stage 5 Ring stage grows and divides, producing merozoites Definitive host 7 Another mosquito bites infected humnan and ingests gametocytes 6 Merozoites are released when red blood cell ruptures; some merozoites infect new red blood cells, and some develop into male and female gametocytes Merozoites Figure 12.19

Cryptosporidium Figure 25.19

Ciliophora (ciliates) Move by cilia Complex cells Balantidium coli is the only human parasite Figure 12.20

Euglenozoa Move by flagella Photoautotrophs Euglenoids Chemoheterotrophs Naegleria Flagellated and amoeboid forms, meningoencephalitis Trypanosoma Undulating membrane, transmitted by vectors Leishmania Flagellated form in sand fly vector, ovoid form in vertebrate host

Euglenozoa Figure 12.21

Helminths Parasitic worms Eukaryotic Multicellular animals Chemoheterotrophic Kingdom: Animalia Phylum: Platyhelminthes (flatworms) Class: Trematodes (flukes) Class: Cestodes (tapeworms) 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 Kingdom: Animalia Phylum: Arthropoda (exoskeleton, jointed legs) Class: Insecta (6 legs) Lice, fleas, mosquitoes Class: Arachnida (8 legs) Mites and ticks May transmit diseases (vectors) Figure 12.31, 32

Arthropods as Vectors Figure 12.33

Putting it Together