Bio 242 - Fungi & Protists

Fungi: Shared Traits

the way in which they derive nutrition: all heterotrophs

Categories of Fungi

Decomposers, mutualists, and parasites (via enzymes)

Fungal Hyphae

filaments that extend into surroundings; secrete enzymes that break down organic matter; absorb release nutrients; seen in multicellular fungi

Spores

enable colonization of new environments; germinate and grow when conditions are favorable

Yeasts

single celled fungi

Mycelium

mats of hyphae

Hyphal structure

Chitin walls; septa or coenocytic

Chitin

Prevents lysing due to osmotic pressure built up during nutrient absorption

Septa

Dividing cells; contain pores that allow cell-to-cell movement of organelles

coenocytic fungi

lack septa; hundreds or thousands of nuclei in a continuous cytoplasmic mass

Mycorrhizae

symbiotic association between a fungus and a plant

arbuscular mycorrhizal fungi

extend arbuscules through the root cellwall and into tubes formed by invagination of the root cell plasmamembrane. (80% of plants)

Ectomycorrhizal fungi

form sheaths of hyphae over the root surface and extend into the extracellular spaces of the root cortex

Fungal Reproduction

Propagation through spore production, either sexually or asexually

Mycisus

General term for fungal infection in animals; accounts for 10-50% of lost fruit harvest

Cryptomycetes

Fungi

Unicellular

Flagellated Spores

30 species

Found Globally in soils, marine and freshwater habitats

often parasites of protists, other fungi

Microsporidia

Fungi

Unicellular

1300 species

Parasite of protists, other fungi

infect host cells with harpoon-like organelle

Vairimorpha ceranae & Vairimorpha bombi- bumble/honey bee parasites

Chytridiomycota

Fungi

Some unicellular, some colony-forming

Found in lakes, soil, marine habitats (hydrothermal vents)

Flagellated spores: zoospores

Decomposers, mutualists, and parasites

Killing FROGS :(

Bd & Bsal

Chytridiomycota

Spread from Asia's global pet trade

Invades skin cells to prevent breathing (Bd), causes ulceration (Bsal)

Cause of decline of 501 species, 90 extinctions

Zoopagomycota

Fungi

Multicellular

Asexual reproduction & formation of filamentous hyphae via non-flagellated spores

900 species

Parasites & commensal symbionts

Induce behavioral changes (zombie-making)

Mucoromycota

Fungi

750 species

Contains important decomposing molds (Rhizopus stolonifer- black bread mold)

Other parasites, pathogens, and mutualists

Coneocytic hyphae

Sporangia (develop at tips of upright hyphae; asexually production of air-dispersed spores)

Ascomycoata

Fungi

90,000 species

marine, freshwater, terrestrial habitats

unicellular to complex cup fungi, morels

called "sac fungi" for their saclike asci

plant pathogens, decomposers, symbionts

See: Penicillium, Bark Beetles

Ascomycoata reproduction

Saclike asci- spore production location

ascocarps- sexual fruiting bodies

conidia- asexual spores used for reproduction

Basidiomycota

Fungi

50,000 species

Mushrooms, puffballs, shelf fungi

Some mutualists (mycorrhizae), parasites (rusts, smuts)

Basidiocarps- sexual reproduction (mush.)

Basidiospores ejected, dispersed by wind

Lichens

Symbiotic associations between photosynthetic microorganisms and fungi

Partner usually w/ ascomycetes

Photo. partner is unicellular or filamentous green algae, cyanobacteria

fungi gives environment, partner gives carbon

given single scientific names

Protist

is an informal term used to refer to all eukaryotes that are not plants,animals, or fungi

Protists contain…

nucleus, other membrane-bound organelles, cytoskeletons

Endosymbiosis

W/ proteobacteria= mitochondria

w/ cyanobacteria= chloroplasts [red algae, green algae, plants]

Protophyta "Algae" (grade)

Photoautotrophs

Plant-like protists

Protozoa (grade)

heterotrophs

animal-like protists

fungus-like protists

"other" (grade)

mixotrophs (auto and heterotrophs)

euglenids (on/off plastids)

ciliates (stolen plastids)

Excavata

Protist

Cytoskeleton

Some have "excavated" feeding grove

Includes diplomonads, parabasalids, and euglenozoans (all monophyletic)

Diplomonads

Protist

Excavata supergroup

See: Giardia intestinalis

found in people who drink untreated water

resides in small intestine

results in diarrhea, dehydration

shed cysts last a long time outside hosts

Euglenozoa

Protist

Excavata supergroup

consists of euglenids and kinetoplastids

Euglenids

Protist

Excavata supergroup, euglenozoa genus

free-living protozoans of ponds

photosynethesize via eyespot