Molds and Mushrooms

Flash cards for BESC 204

Fungi Kingdom (Ch. 1)

Fungi Kingdom (Ch. 1)

Also known as mycota, their primary ecological function is degradation, and they are pathogens to plants, animals, and humans. (It could even be for other fungi).

Functions of fungi (Ch. 1)

Fungi can produce secondary metabolites, be a source of food, and can be often seen in symbiotic relationships.

Mycology (Ch. 2)

Mycology is the study of fungi. (Mykes = mushroom logos = discourse.)

What is fungus? (Ch. 2)

A eukaryotic (meaning they contain a nucleus and other membrane-bound organelles), heterotrophic organism; devoid of chlorophyll; with chitin in cell walls; that obtains its nutrients by absorption, usually reproduces by spores and usually exhibits a pronounced polarization of growing cells.

Fungi are multi-cellular organisms, with a unique system of “Cell Compartmentalization”.

NOTE: if single-celled, it could be a yeast.

“Cell Compartmentalization” (Ch. 2)

Compartmentalization in cells is the separation of the cell interior into distinct compartments with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes. In eukaryotic cells, a system of internal membranes and organelles generates compartmentalization.

Characteristics of fungi (Ch. 2)

Mainly composed of hyphae that elongate by tip growth.

All are heterotrophs with absorptive nutrition (saprotrophs) They have no chlorophyll and are not autotrophic

Cell walls of most contain Chitin a structural polymer of glucose (Plants=cellulose Animals=no cell wall)

Hyphae (Ch. 2)

Hyphae are the feathery filaments that make up multicellular fungi. They release enzymes and absorb nutrients from a food source. Hyphae have a firm cell wall made of chitin. They grow from a tip and extend out in search of more food sources.

Chitin (Ch. 2)

Chitin exists in the spores and hyphal cell walls in conjunction with glucan molecules forming microfibrils. These microfibrils are embedded in an amorphous matrix to provide the framework and cell wall morphology and rigidity.

Mycelium (Ch. 2)

A web of hyphae (Hyphae collectively comprise the mycelium.)

Septa (Ch. 2)

Fungal Hyphae of many species contain septa.

The hyphae of most fungi are divided into cells by internal walls called septa (singular, septum). Septa usually have little pores that are large enough to allow ribosomes, mitochondria and sometimes nuclei to flow among cells. Hyphae that are divided into cells are called septate hyphae.

Spores (Ch. 2)

Reproductive propagules, usually microscopic.

Sexual spores (Ch. 2)

Sexual Spores: products of Meiosis

-Ascospores

-Basidiospores

-Zygospores

-Zoospores (meiotic)

Asexual spores (Ch. 2)

Asexual Spores: products of Mitosis

-Zoospores

-Sporangiospores

-Conidia

Morphological species concept (Ch. 3)

Things that look the same are of the same species. Most fungal species defined this way (particularly for species that have no known sexual reproduction).

Biological species concept (Ch. 3)

Interbreeding or potentially interbreeding natural populations are the same species.

Strains that can mate in the laboratory may not be able to mate in nature and could be different species, however, operationally, mating in the lab is often used to define a member of a species.

Phylogenetic species concept (Ch. 3)

Individuals of the same species share a genealogical relationship inferred by phylogenetic analysis. Assumes monophyly. Using phylogenetic analysis we can identify recombination within populations to determine which groups are interbreeding (share a common gene pool).

Conidia (Ch. 3)

Conidium, a type of asexual reproductive spore of fungi (kingdom Fungi) usually produced at the tip or side of hyphae (filaments that make up the body of a typical fungus) or on special spore-producing structures called conidiophores. The spores detach when mature.

Chytridiomycota characteristics (Ch. 3)

• “True Fungi” with flagellate spores both Zoospores in sporangia

• They do not make hyphae

• The thallus is coenocytic (septa are rare or absent)

• Cell walls contain chitin and Cellulose

• Mostly aquatic or soil-inhabiting saprobes, a few are parasitic on plants, animals, and fungi

Blastocladiomycota characteristics (Ch. 3)

• Often referred to colloquially as ‘Chytrids’

• Mostly aquatic or soil-inhabiting saprobes,

• They are “True Fungi” with flagellate spores Zoospores in sporangia

• They do make hyphae, but septa are rare or absent

• Complex life cycles

Chytridiomycota Vs. Blastocladiomycota (Ch. 3)

Former Chytridiomycota are divided into two taxa:

Chytridiomycota: no hyphae, zoospores

Blastocladiomycota: with hyphae (no septa), zoospores

Zygomycota characteristics (Ch. 4)

• THE ZYGOSPORE

• Asexual spores are sporangiospores made in a sporangium

• With true hyphae that are mainly coenocytic, no septa in most newly developed hyphae.

• Terrestrial

• Cell walls have: Chitan, chitosan (non- acecylated chitan) and polyglucuronic acid

Sporangium (Ch. 4)

A sporangium is a structure in certain plants and other organisms that is charged with making and storing spores. Spores are haploid structures created in organisms that help to germinate and form new organisms. In other words, they help organisms to reproduce.

Zygomycota mating type (Ch. 4)

Here + and –

Not the same as male and female, since the + mating type can make male or female structures and – can make male or female structures.

• These + or – are determined by a single locus, with a different idiomorphic gene present at the locus for each.

Heterothallic (Ch. 4)

Having male and female reproductive organs on different thalli. (of some fungi) having sexual reproduction that occurs only between two self-sterile mycelia.

• Heterothallic fungi are self-sterile: they require another compatible individual for sexual reproduction.

Homothallic (Ch. 4)

The possession, within a single organism, of the resources to reproduce sexually; i.e., having male and female reproductive structures on the same thallus.

• Homothallic fungi are self-fertile: they can sexually reproduce in a culture derived from a single spore or cell.

Zoopagomycota (Ch. 4)

• All make a ZYGOSPORE as the sexual spore

• Asexual spores are sporangiospores made in a sporangium...sporangia often germinate directly.

• With true hyphae that are mainly coenocytic, no septa in most newly developed hyphae.

• Terrestrial Most are typically insect or other animal pathogens.

Sporangium pt. 2 (Asexual development) (Ch. 4)

Phototropism of Pilobolus

Aerial growth directed toward the light.

Black spore mass at head of sporangium is ejected 3 meters after rupture of sub-sporangial vesicle.

Parasitic nematode larvae crawl up sporangium are launched along with spores.

Zygomycota Vs. Zoopagomycota (Ch. 4)

Former Zygomycota are divided into two taxa:

Zygomycota: hyphae, no septa, zygospores, sporangiospores

Zoopagomycota: hyphae, no septa, zygospores, sporangiospores (~conidia), pathogens of animals

Ascomycota characteristics (Ch. 5)

Have regularly spaced septa (usually with a central pore) Cell walls contain chitin and glucans

Never produce motile spores

When produced, conidia (the asexual spores) are never produced by cytoplasmic cleavage in a sporangium

Certainly a monophyletic group

Ascus (Ch. 5)

• Production of an Ascus (Asci plural)

• An Ascus is a sac-like structure filled with ascospores

Ascomycota reproduction (Ch. 5)

• Generally, Ascomycetes are thought to reproduce both sexually and asexually

• Some have only a sexual state known while others have only an asexual stage known.

Thallus (Ch. 5)

The thallus of a fungus is usually called a mycelium. The term thallus is also commonly used to refer to the vegetative body of a lichen. In seaweed, thallus is sometimes also called 'frond'. The gametophyte of some non-thallophyte plants – clubmosses, horsetails, and ferns is termed "prothallus".

Ascomycota characteristics (Ch. 5)

Thallus varies from single-celled to well-developed mycelium with regularly spaced septa. Most septa posses a single central pore. Small spherical structures called Woronin bodies which are typically associated with each septum.

Woronin bodies (Ch. 5)

Woronin bodies are membrane-bound organelles of filamentous ascomycetes that mediate hyphal compartmentalization by plugging septal pores upon hyphal damage. Their major component is the peroxisomal protein Hex1, which has also been implicated in additional cellular processes in fungi.

Central pore (Ch. 5)

Central pore- At the center of the septum lies a septal pore that allows the exchange of cytoplasmic constituents between flanking cells

Gametangial fusion (Ch. 5)

Ascogenous hyphae develop near paired nuclei are outgrowths from the ascogonium paired nuceli migrate into each hypha.

Tip cell curves to form a Crozier

Meiosis and then mitosis happens

A system of endomembranes form cleaving out the cytoplasm around the nucleus to form ascospores

Ascocarps (Ch. 5)

An ascocarp, or ascoma ( pl. : ascomata), is the fruiting body (sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores.

Type 1 ascocarp (Ch. 5)

Perithecium (perithecia pl.) a closed ascocarp with a pore (ostiole) at the top, and a wall of its own.

Type 2 ascocarp (Ch. 5)

Apothecium (apothecia pl.) an open ascocarp.

Type 3 ascocarp (Ch. 5)

Cleistothecium (cleistothecia pl.) a completely closed ascocarp

Types of spore spread (Ch. 5)

1. Fruit body expanding

2. Cut open fruit body

3. Hymenium: Ascospore discharge

4. Puffing

Ascomycota sexual stages (Ch. 5)

• Sexual Stage= “perfect” stage or Meiotic stage producing meiospores

• Asexual Stage= “imperfect” stage or Mitotic stage producing mitospores

Holomorph (Ch. 5)

All forms (morphs) of the fungus, either latent or expressed.

Anamorph (Ch. 5)

Asexual (imperfect, mitotic) form(s).

Teleomorph (Ch. 5)

Sexual (perfect, meiotic) form.

Basidiomycota characteristics (Ch. 6)

Produce a Basidium. Usually produced on a macroscopic Basidiocarp.

Production of a well developed septate mycelium

Production of clamp connections in some species

Presence of Dolipore septa in some species

Extended dikaryotic stage

Dikaryotic (Ch. 6)

Organisms that contain two genetically distinct cell nuclei in the same cell are called dikaryotic. These organisms consist of genetically dissimilar but have two cell nuclei in the same cell. These are unique to fungi, especially Ascomycetes, and basidiomycetes.

Basidiomycota septal pores (Ch. 6)

Dolipore septa, septal pore caps or parenthosomes

Parenthesomes (Ch. 6)

Within the cells of some members of basidiomycetes fungi are found microscopic structures called parenthesomes or septal pore caps. They are shaped like parentheses and found on either side of pores in the dolipore septum which separates cells within a hypha.

Dolipore (Ch. 6)

Dolipore septa are specialized dividing walls between cells (septa) found in almost all species of fungi in the phylum Basidiomycota. This structure allows cytoplasm and tiny organelles to pass through, but nuclei movement is restricted to variable degrees.

Clamp connections (Ch. 6)

A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of basidiomycete fungi.

Basidiomycota spores (Ch. 6)

Most Basidiomycota form their basidiospores in/on a structure called the Basidiocarp.

Basidia and basidiospores (Ch. 6)

A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia.

Basidiomycetes vs. Ascomycetes characteristics (Ch. 6)

• Compartmentalized mycelium

• Dikaryotic Stage (But it is extended in Basidiomycetes)

• Specialized Spore producing tissues. (The hymenium)

• Production of conidia (though this is rare in Basidiomycota)

The two groups very likely derive from a common ancestor

Basidiocarp variety: Agarics (Ch. 6)

Agarics- The hymenium is found on the surface of the gills.

Basidiocarp variety: Boletes (Ch. 6)

Boletes— hymenium lines pores or tubes, fleshy basidiocarp.

Basidiocarp variety: Chanterelles (Ch. 6)

Chanterelles— hymenium on gill-like folds.

Basidiocarp variety: Toothed fungi (Ch. 6)

Toothed fungi— hymenium on small spines.

Gasteromycetes (Ch. 6)

• Spores not discharged at maturity as with Ballistospores and are therefore sometimes referred to as Statismospores.

• They simply fall off of their Basidia/Sterigma at maturity into the spore mass of the Gleba.