Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 1 Fungi 2; Slime molds Reproduction; Fungal divisions

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 2 Asexual sporulation Mitosis and cell division to form several types of asexual spores Reproduction Arthroconidia or arthrospores Cells fragmented by formation of new septa. New cells function as spores. Chlamydospores Cells surrounded by thick walls before separation. Sporangiospores Spores developed within a sac (sporangium). Conidiospores Not in sac but on tips or sides of hypha. Blastospores Produced from mother cells by budding.

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 3 Sexual sporulation Reproduction Meiosis and fusion; spores genetically different from mother cells. Specialized hyphal structures form fruiting bodies which produce spores. Three stages of sexual reproduction: Fruiting body and spore structures vary with phyla. Spores distributed by wind, water and vectors. 1. Donor (+) haploid nucleus penetrates cytoplasm of recipient cell (-). 2. (+) and (-) nuclei fuse  diploid zygote. 3. Diploid nucleus gives rise to haploid spores via meiosis (some spores may be genetic recombinants).

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 4 Reproduction The asexual life cycle of Rhizopus, a zygomycete Tortora et al., 2001; Fig

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 5 Reproduction The sexual life cycle of Rhizopus, a zygomycete Tortora et al., 2001; Fig

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 6 Reproduction The life cycle of Eupenicllium, an ascomycete Tortora et al., 2001; Fig )

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 7 Reproduction A generalized life cycle of a basidiomycete Tortora et al., 2001; Fig. 12.8

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 8 Characteristics of the fungal divisions Classification based primarily on variations in production of sexual spores. Characteristics of Fungal Phyla HyphaePropagationApprox. No. of Species Zygomycotaaseptatesexual sporulation600 Ascomycotaseptatesexual sporulation35,000 Deuteromycotaseptateasexual sporulation hyphal structures 30,000 Basidiomycotaseptatesexual sporulation asexual sporulation 30,000 Four major phyla of fungi.

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 9 Division Zygomycota Characteristics of the fungal divisions Known as the conjugation fungi. Asexual spores: sporangium (pl. –gia). Sexual spores: thick-walled resting spores (zygospores) Example: Rhizopus stolonifer

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 10 Division Ascomycota Characteristics of the fungal divisions Known as the sac fungi after the sac-like ascus (pl. asci) in which spores are borne. Many red, brown and blue-green spoilage fungi belong to this division Many are parasites on higher plants e.g. Claviceps purpurea (ergot of cereals).

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 11 Division Basidiomycota Characteristics of the fungal divisions Known as the club fungi after the club-shaped basidium involved in sexual reproduction. Spores borne externally on the basidium. Most are saprophytes. Crytococcus neoformans is an important human pathogen (crytococcosis – lung infection). Many mushrooms used as foods e.g. Agaricus campestris, Lentinus edodes, Pleurotus sp.

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 12 Division Deuteromycota Characteristics of the fungal divisions Fungi without a known sexual reproductive stage. Therefore, limited to chlamydospores, arthrospores, conidiospores and budding. Also known as the Fungi Imperfecti; a “holding category”. Saprophytes and parasites (e.g. in athelete’s foot and ringworm); most terrestrial. Important in industry e.g. Penicillium (antibiotics; cheese making), Aspergillus sp. (enzymes).

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 13 Division Chytridiomycota Characteristics of the fungal divisions Simplest of the true fungi Terrestrial and aquatic. Motile sexual and asexual spores. Asexual reproduction: motile zoospores Sexual reproduction: Zygote.

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 14 Have both fungal and animal characteristics; therefore are protists. Slime Molds Division Myxomycota (plasmodial slime molds) Streaming masses of colorful protoplasm (plasmodium – no cell walls). Feeding is by phagocytosis. Reproduction.  When mature (or under unfavorable conditions), ornate fruting bodies are developed.  Spores germinate to form either myxamoebae (non-flagellated) or flagellated swarm cells (both haploid).  The latter and former fuse to form zygotes which grows into the multinucleate plasmodium.

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 15 Slime Molds Totora et al., 2001; Fig.12.22

Dr. Clem Kuek ZIP\Lectures\Basic\Lectures\Fungi\Fungi2\Fungi2.ppt 16 Slime Molds Division Acrasiomycota (cellular slime molds) Totora et al., 2001; Fig.12.21