Presentation on theme: "Kingdom: Fungi Five kingdom system of classifying living things showing that both fungi and animals may have evolved from a common ancestor."— Presentation transcript:
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
FungiEukaryotes 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. Fungi are important as pathogens of animals and plants. Over 70% of all plant diseases are caused by fungi 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.
Classification Fungi based on there sexual reproduction : Zygomycetes: zygospores, ex. Mucor & Rhizopus Rhizopus Mucor
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
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.
Mycology Basidiomycota Have septate hyphae Have asexual conidiospores Have sexual basidiospores. Basidiospores are formed externally on a base pedestal called a basidium
Deuteromycetes: not produce any sexual spores, ex.: Monilia fungi & Botrytis Monilia fungiBotrytis
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 37 0 C the organism grows as a yeast-like form and at RT or at 25 0 C it grows in a mold-like form. CO 2 concentration or the presence of serum may also be a determining factor
Classification Fungi according to nutrion: Saprophytic Parasitic Symbiotic or Mycorrhizal
plant cell fungal cells plant cell membrane plant cell wall How do Fungi get their Nutrition? Heterotrophs Heterotrophs secrete digestive enzymes secrete digestive enzymes absorb digested material into cell absorb digested material into cell predators predators paralyzing prey paralyzing prey parasites parasites feeding on living creatures feeding on living creatures decomposer decomposer breakdown dead remains breakdown dead remains
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.
Cross Walls of Hyphae coenocytic having multiple nuclei embedded in cytoplasm without cross walls; nonseptate 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