Lab: Fungal Biology Study Notes

Zygote and Fungal Reproduction

  • Zygomaticota

    • Genus: Rhizopus

    • Also known as red mold.

    • Commonly seen on moldy bread, which consists of a collection of fungal hyphae.

    • Fungal Hyphae:

      • Definition: Fungal filaments that form the vegetative part of fungi.

      • Visual description: Blue strands in fungal structures are the hyphae.

    • Reproductive Structures:

    • Sporangia:

      • Defined as spore-forming structures.

      • Appears as spherical structures with spores attached.

      • Distinctive appearance of rhizopus spore-forming structures is noted.

    • Zygote Formation:

      • Rhizopus can reproduce sexually through combination of egg and sperm or by fusion of different fungal parts leading to a zygote.

      • Visual description: Zygotes are depicted visually.

      • Sporangia and zygote slides may vary; focus on differences in reproductive structures as shown in slides.

Structure of Rhizopus

  • Hyphae Types:

    • Hyphae:

    • All filaments of the fungus are hyphae, which collectively form the mycelium.

    • Rhizoids:

    • Function: Anchor the fungus to its substrate (e.g. bread).

    • Analogous to roots in plants.

    • Mycelium:

    • Complete network consisting of all the hyphae together.

    • Stolon:

    • Type of hypha that connects different parts of the fungus, similar to a bridge.

Fungal Reproductive Structures

  • Sporangium:

    • Structure:

    • Comprises a stalk (referred to as the stipe) and a fleshy part called the colobella leading to sporangia that contain spores.

    • Zygote Formation:

    • Result of the fusion of different cells within the fungi.

Phylum Ascomycota

  • Genus: Peziza

    • Type: Cup fungus characterized by a cup shape.

    • Structure:

    • Cross-sectional view reveals spores contained in the cup structure.

    • Spores are produced in sacs called asci.

    • The individual spores within these sacs are known as ascospores.

  • Single-Celled Fungi:

    • Definition: Yeasts are classified as single-celled fungi.

    • Genus: Saccharomyces (species: Saccharomyces cerevisiae):

    • Utilized in baking and brewing for bread and beer production.

    • Genus: Candida:

    • Not edible; causes infections (e.g., yeast infections).

    • Definition: Yeasts reproduce via budding, a process whereby a smaller cell develops from a larger one.

    • Identifying Feature: Look for budding under the microscope to designate yeast.

Penicillium and Other Fungi

  • Genus: Penicillium

    • Utilized to produce penicillin and can grow on moldy food.

    • Identify by conidia, which are spores produced by the fungus, and appear in various orientations when observed microscopically.

  • Pneumocystis:

    • Causes pneumonia, primarily affecting immunocompromised individuals.

    • Appearance: Found within the lung air sacs, identifiable by the surrounding epithelial cells.

Lichens

  • Definition: Mutualistic association between fungi and algae or cyanobacteria.

  • Visual Features:

    • Composed of fungal hyphae intertwined with algal cells, which are usually stained red in prepared slides.

  • Algal Metabolism:

    • Algae perform photosynthesis, providing sugars to fungi.

    • Fungi provide water and minerals to algae, creating a mutualistic relationship.

Phylum Basidiomycota

  • Genus: Puccinia (Plant Rust)

    • Identified by red spots found on the underside of plant leaves, indicative of fungal infection.

    • Reproductive structures erupt from plant tissues, producing spores as visible red spots.

  • Genus: Agaricus

    • Represents common edible mushrooms (e.g., button mushrooms).

    • Features:

    • Cap (pileus) at the top, covered with gills where spores are released.

    • Basidia: Reproductive structures where spores (basidiospores) are produced, evident under microscopic examination.

Practical Notes

  • Identification: Important skills involve distinguishing different fungal species based on structure and reproductive methods.

  • Safety Consideration: Advisement against consuming unidentified wild mushrooms due to potential toxicity.

Specimens and Visual Aids

  • A variety of fungal specimens are available for examination, including lichen and various fungi types. Examine microscopic slides carefully for all structural details noted during the lecture.

  • Collection Considerations:

    • Specimens must be handled delicately to avoid damage during observation.