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FUNGI
ALGAE
PROTOZOA
HELMINTHS
ARTHROPODS

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Mycology is the study of fungi
Fungal characteristics:
 eukaryotic
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Energy Source: chemoheterotrophs ( saprophytic )
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O
2 needs: aerobic, facultative anaerobic
Form: multicellular (molds), unicellular (yeasts) dimorphic fungi have both forms
Cell wall contains chitin
Classified based on their form of sexual reproduction

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Thallus : the body of the mold or fleshy fungus (mushrooms) consists of long filaments called hyphae which are joined together
Hyphae in most molds are divided into individual cell units by septa (cross walls)
Coenocytic hyphae do not have septa (aseptate)

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Reproduce by two different kinds of division fission yeasts - undergo binary fission budding yeasts - divide unevenly through buds pseudohyphae are short chains formed when the buds do not completely separate

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"conjugation" fungi (fig. 12.6, p. 337)
Zygospore - large spore enclosed by a thick wall sexual reproduction by zygospores
(union of two nuclei from mating strains of fungus) asexual reproduction by sporangiospores in a sporangium coenocytic hyphae (no septa/cross walls)
Example : Rhizopus (includes black bread mold)

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"sac" fungi (fig. 12.7, p. 338) sexual reproduction by ascospores in a sac called an ascus asexual reproduction by conidiospores on conidia septate hyphae
Examples: Sachcharomyces - brewer’s yeast, Aspergillus, Histoplasma

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"club" fungi (fig. 12.8, p. 339) sexual reproduction by basidiospores on a pedestal called a basidium asexual reproduction by fragmentation septate hyphae
Examples: Coprinus, Amanita

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"fungi imperfecti” - a ‘holding category’ for organisms in which sexual reproduction is not discovered… may exist though.
Why ‘imperfect’? -- no known sexual reproduction asexual reproduction by conidiospores septate hyphae
Example : Candida albicans

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a fungal infection is called a mycosis (plural = mycoses) cutaneous mycoses: fungal infections of the hair, skin, and nails subcutaneous mycoses: infections under the skin, often occur by direct implantation of fungal spores or mycelium into a puncture of the skin systemic mycoses: deep in the body, can affect multiple organs and tissues

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some fungi are opportunistic pathogens
Example: candidiasis (yeast infection, thrush) Candida albicans

simple eukaryotes - unicellular, colonial, and multicellular photoautotrophs vegetative structures:
16 body of multicellular alga is called a thallus some have holdfasts , stem-like stipes , and leaf-like blades live in water habitats divisions determined by a number of characteristics, including: pigments, cell wall types, and food storage polymers

Brown algae: macroscopic (some up to 50 m long) producers of algin (used as commercial food thickener such as in ice cream, sour cream, yogurt)
Red algae: delicately branched, live at great depth source of agar
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Green algae: cellulose cell walls, chlorophyll a and b believed to be precursor to terrestrial plants

Diatoms silica in cell wall can produce domoic acid - a toxin concentrated by shellfish
Dinoflagellates: unicellular algae, known as plankton produce neurotoxins
Gonyaulax , dinoflagellate found in red tides, produce saxitoxins that cause paralytic shellfish poisoning
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Euglenoids: unicellular, flagellated algae have rigid cell membrane (pellicle), but no cell wall contain a red eyespot

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A lichen is a combination of a green alga (or cyanobacterium) and a fungus they live together in a mutualistic relationship (both benefit) & occupy habitats where neither would survive alone fungus provides holdfast and protection algae provides nutrients through photosynthesis chemical weathering of rocks by lichens contributes to soil formation

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have characteristics of both fungi and animals (classified as protists) complex life cycle (see figs. 12.21 & 12.22, p. 356-7) slime molds resemble giant amoebas life singly, or in aggregates called a plasmodium representative genus: Dictyostelium

have both asexual and sexual reproduction some produce cysts for survival in adverse conditions
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Sarcodina - amoebas
Mastigophora - flagellates
Ciliophora – ciliates
Apicomplexa - nonmotile

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Sarcodina :
Entamoeba histolytica , amoebic dysentery
Naegleria fowleri , meningocephalitis
Mastigophora
Giardia lamblia , giardial enteritis
Trichomonas vaginalis , vaginitis
Trypanosoma cruzi
(Chaga’s disease)
T. brucei (African trypanosomiasis)

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Ciliophora
Balantidium coli , dysentery (only parasitic ciliate of humans)
Apicomplexa
Plasmodium , malaria (through bite of Anopheles mosquito)
Toxoplasma gondii , toxoplasmosis

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multicellular, eukaryotes generally possess digestive, circulatory, nervous, excretory, and reproductive systems when parasitic may:
 lack digestive system
 have reduced nervous system
 have reduced locomotion but no reduction in reproductive system can have complex lifecycle with successive intermediate hosts for larval stages and a definitive host for the adult parasite
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Reproductively may be: monoecious : male and female reproductive organs in one organism dioecious : male and female reproductive organs on separate individuals

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Two major groups

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flat, leaf-shaped bodies with ventral and oral sucker (fig. 12.22) can also absorb food through their outer layer (cuticle) common names from tissue of definitive host in which they reside
(liver fluke, lung fluke, etc.)
Paragonimus life cycle (fig. 12.24)
Schistosoma – blood fluke are not ingested, but burrow through skin
Clonorchis – Asian liver fluke (no intermediate hosts in USA) sometimes seen in immigrants, not transmitted

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Scolex – ‘head’ of suckers & hooks attaches to intestinal mucosa see photo on
12.25 p 360 body consists of segments called proglottids : each segment contains a complete, monoecious reproductive system (male & female)
Taenia saginata (beef tapeworm) - humans are definitive host cattle are intermediate host
Proglottids wiggle away from feces increasing their chances of being eaten by cattle in surrounding grass.
eggs hatch, larvae migrate to muscle, encyst as cysticerci in muscle which is eaten by humans
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Attach to intestinal wall by scolex, grow & reproduce

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Echinococcus granulosus – dog tapeworm
Taenia solium – pork tapeworm

Most species are dioecious some infect humans as eggs : Enterobius – pinworm, female migrates to anus to lay eggs (diagnosis by tape method) acquired by exposure to contaminated bedding
Ascaris lumbricoides which exhibits sexual dimorphism – eggs in soil, accidental ingestion some infect humans as larvae (hookworm, Necator americanus which enters through skin -- prevented by wearing shoes;
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Trichinella spiralis , cause of trichinosis, acquired by eating larvae in poorly cooked pork)

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Arthropods (joint footed) are the largest phylum in the animal kingdom
Includes: Insects, Arachnids, Crustaceans can act as vectors (transmitters) of many pathogenic microorganisms
Mites and ticks: some carry Rocky Mountain spotted fever,
Lyme disease, relapsing fever
Sucking lice: epidemic typhus
Fleas: endemic murine typhus, plague

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Flies (includes mosquitoes): Tularemia, Dengue fever, yellow fever, malaria, arboviral encephalitis, African trypanosomiasis
True bugs: Chaga’s disease (kissing bug)

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