Kingdom: Fungi

Five kingdom system of classifying living things showing that both fungi and animals may have evolved from a common ancestor

Mycology Mycology is the study of fungi which includes yeast and molds They are eukaryotic and are chemo-heterotrophs (require organic compounds for energy and a carbon source) Most have a cell wall of chitin Molds are made of long filaments called hyphae If there are cross walls that divide the hyphae into uninucleate units the hyphae are septate hyphae If there are no cross walls, the hyphae are called non-septate or coenocytic hyphae When the hyphae grow and intertwine to form a mass, they are called mycelium

Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy. Molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae. Yeasts are unicellular. Figure 1.1b

Fungi are important as pathogens of animals and plants. Over 70% of all plant diseases are caused by fungi

Mycelium are of three kinds: 1- vegetative mycelium ( penetrates the surface of the medium and absors nutrients 2- Aerial mycelium ( grow above the agar surface) 3- Fertile mycelium (bear reproductive structure such as conidia or sporangia)

Yeasts are non-filamentous, unicellular fungi that are oval or spherical in shape. Yeasts reproduce by the process of budding or binary fission.

Candida albicans

Classification Fungi based on there sexual reproduction : Zygomycetes: zygospores, ex. Mucor & Rhizopus Mucor Rhizopus

Mycology Fungi are classified based on the type of sexual spore that they form Zygomycota Have non-septate hyphea Have asexual sporangiospores Form sexual zygospores. They are large spores enclosed in a thick wall and formed from the fusion of two cells

Zygospores

Ascomycetes : Ascospores, ex: saccharomyces, Aspergillus & Penicillium Yeast Aspergillus Penicillium

Mycology Ascomycota Have septate hyphae Have asexual conidiospores Have sexual ascospores. Ascospores result from the fusion of nuclei of two cells. They are produced in a sac-like structure called an ascus.

Ascospores inside an ascus

Basidiomycetes: Basidiospores, ex.: Rust fungi & Mushroom.

Mycology Basidiomycota Have septate hyphae Have asexual conidiospores Have sexual basidiospores. Basidiospores are formed externally on a base pedestal called a basidium

Basidiospores

Deuteromycetes: not produce any sexual spores, ex Deuteromycetes: not produce any sexual spores, ex.: Monilia fungi & Botrytis Monilia fungi Botrytis

Classification Fungi based on morphology: Moulds (Molds): Filamentous fungi Eg. Aspergillus Yeast : Eg. Saccharomyces Yeast like: Similar to yeasts but produce psedohypha Eg. candida albicans Dimorphic: Two different morphological form at two different enivormental conditions

Mycology Dimorphic fungi Some fungi, including most of the pathogenic fungi, exhibit two forms of growth. This is known as dimorphism and the organisms can grow either as a yeast-like form or a mold-like form. Frequently the form that the organism grows as is temperature dependent and at 370 C the organism grows as a yeast-like form and at RT or at 250 C it grows in a mold-like form. CO2 concentration or the presence of serum may also be a determining factor

Classification Fungi according to nutrion: Saprophytic Parasitic Symbiotic or Mycorrhizal

How do Fungi get their Nutrition? Heterotrophs secrete digestive enzymes absorb digested material into cell predators paralyzing prey parasites feeding on living creatures decomposer breakdown dead remains fungal cells plant cell wall plant cell membrane plant cell

Laboratory identification fungi: Specimen collection: soil, moldy food, plants, water, air,……etc. Microscopy: Lactophenol cotton blue Culture : Potato Dextrose Agar (PDA)

Classification Fungi based on hypha: Septate – Non septate Somatic hyphae. A) Portion of a hypha having more than one nucleus (nonseptate); B) Portion of a septate hypha.

                                   coenocytic    having multiple nuclei embedded in cytoplasm without cross walls; nonseptate Cross Walls of Hyphae Coenocytic hyphae where the nucleis of each cell is embedded in the cytoplasm without a cell wall Eg. Zygomycota, Oomycota Hyphae with cross walls Eg. Basidiomycota, Ascomycota