Mycology: Gymnomycota or Myxomycota

What are the 3 divisions of the kingdom Myceteae

1. Gymnomycota

2. Mastigomycota

3. Amastigomycota

What are the 2 sub-divisions of the division Gymnomycota?

1. Acrasiogymnomycotina

2. Plasmodiogymnomycotina

What is included in the Myxomycota division?

• Slime mold

• Plasmodial slime mold

• Net slime mold

Why were they termed Mycetozoa?

The presence of their naked cell and phagotrophic

Why were Slime molds once thought to be fungi?

They produce spores that are borne in sporangia

The assimilative stage in slime molds is morphologically similar to that of an amoeba. (T/F)

True

What is the assimilative stage?

The vegetative stage

What was the assimilated stage designated as?

Myxamoeba

What are the distinguishable characteristics of the slime mold?

1. Ingests particulate nutrients

2. Vegetative stage (assimilative stage) lacks cell walls

3. Poses characteristics of both Animal and Fungi

   • Fungi: Reproduce by spores

   • Animal: Slimy, naked, multinucleated/unnucleated mass of protoplasm

Mycologists still recognize slime molds as being fungi. (T/F)

False, they no longer do

Why are RNAs used to study ansestry?

It takes a long time to change

How are True fungi different from Slime molds?

True fungi

• Form hyphae

• Cell wall throughout most of its life cycle

• EXCLUSIVELY ABSORB nutrition

Slime mold

• No hyphae

• No cell wall (In vegetative stage)

• Can ingest by phagocytosis using pseudopodia and hydrolytic enzymes

⚠What are the 2 groups of Slime molds and how are they different?

1. Cellular slime molds

   • Vegetative stage: Myxamoeba = HAPLOID ameboid cell

2. Acellular (True) slime molds

   • Vegetative stage: Plasmodium (Plasmodia) = Multinucleate DIPLOID ameboid mass

Both Cellular and Acellular slime mold groups grow in moist or decaying plant matter as red, white, or yellow color. (T/F)

True

What are the Sub-divisions and classes of Gymnomycota/Myxomycota?

1. Acrasiogymnomycotina

   • Acrasiomycetes

2. Plasmodiogymnomycotina

   • Protosteliomycetes

   • Myxomycetes

Acrasiogymnomycotina are cellular slime molds. (T/F)

True.

Acrasiogymnomycotina spend most of the life-cycle as what?

Free living, amoeba-like cells (They are phagocytic)

Found near rich sources of food

When do Acrasiogymnomycotina aggregate and form a slimy mass (Pseudoplasmodium) and why do they do it?

When nutrients are scarce and low.

To migrate to a more favorable location and form spores.

When they aggregate and form Pseudoplasmodium, the cell membrane keeps them separate. (T/F)

True

Acrasiogymnomycotina Reproduce sexually. (T/F)

False, Asexual reproduction with no diploid stage

Plasmodiogymnomycotina are Acellular slime molds. (T/F)

True

Plasmodiogymnomycotina form Plasmodium. (T/F)

True

The Myxomycetes from the Plasmodiogymnomycotina sub-division have delicate structures and colorful fruiting bodies. (T/F)

True

Why are Myxomycetes called slime molds/fungi?

Because they exist in non-green slimy masses of protoplasm, sending out pseudopodia

Myxomycetes class do not include the true plasmodial acellular slime molds

False, they include the true plasmodial acellular slime molds.

Myxomycetes class reproduce asexually just like Acrasiogymnomycotina sub-division. (T/F)

False, While Acrasiogymnomycotina reproduce by asexual reproduction, Myxomycetes can reproduce Asexually, Sexually, and by Vegetatively

What is Plasmodium?

• The fusion of the cytoplasm and nuclei

• Diploid zygote goes through multiple nuclear divisions to form a multinucleated Plasmodium

• Plasmodia are a multinucleated masses

• Plasmodia gain nutrients through phagocytosis

• Forms a Sclerotium in unfavorable conditions

  • Form a protective brittle layer

  • The Plasmodium is restored when the Sclerotium absorbs water in moist conditions

• The plasmodium will enter the next stage of its life cycle when the food wanes

  • Forming haploid spores, often in a well-defined sporangium

The sporophores in the endosporous Myxomycetes chiefly are of three types. What are they?

1. Sporangia

2. Aethalia

3. Plasodiocarps

What is a Sporangium?

• Plural Sporangia

• Fruiting structure of a plasmodium

• The sporangia in the group remain separate from one another.

• The abundantly produced spores are stored in a reticular or filamentous structure – the so-called capillitium

The capillitium are found on nearly all species (T/F)

True

What type of fruiting bodies do Lycogala and Fuligo form?

Aethalia

How are Aethalia?

The Plasmodium, at the fruiting time, is a fairly large structure. It becomes converted into a group of saclike sporangia that do not separate from one another.

What are Plasmodiocarps?

• In forms like Hemitrichia

  • fruit body is very much like a sessile sporangium that retains the shape of the plasmodial venation

• formed by the concentration of the plasmodial protoplasm around some of the main veins, followed by the development of the peridium around each

What is the Life cycle of Physarum?