3 SLIME MOLDS Vegetative thallus – lacks a cell wall, move about like amoeba,resemble some protozoa,ingests food particles by phagocytosis,inhabit damp soils, especially areas rich in decomposing plant material,May be multinucleate (Plasmodial SM) or independent amoeboid cell (Cellular SM)
4 Phylum Acrasiomycota (Cellular slime molds) 3 genera, 50 spp.Vegetative thallus – amoeboid cells that aggregate to form pseudoplasmodiumproduce walled spores during reproductionCellular slime molds contain cellulose in their spore wallwidespread in forest soils, dung, decaying plant matterFeed on bacteria in soil as amoeboid cellswithout flagella
12 GENERAL CHARACTERISTICS OF FUNGI Eukaryotic heterotrophs that digest food externally and absorb the the digested materials through their body walls.Many are ecologically important saprophytes (consume dead and decaying matter). Others are parasites or mutualists. Parasitic fungi absorb nutrients from their host through specialized hyphae called haustoria.Over 100,000 fungal species identified. It is estimated there are actually 1.5 million species of fungiOnly about 100 are human or animal pathogens.Most human fungal infections occur in immunocompromised individuals (opportunistic infections).Fungal diseases in plants cause over 1 billion dollars/year in losses.Multicellular, but yeasts are unicellular.Most are aerobes or facultative anaerobes.Cell walls are made up of chitin (polysaccharide).Reproduce sexually and asexuallyAsexually by sporesSexually by mating of hyphae filaments from two genetically different fungiFungi are classified by the shape of their sporangium and the way they produce sexual spores.
13 Hyphae are the basic structure of threadlike filaments that grow from a fungal spore. Hyphae grow into a mycelium – a cottony mass covering and distributed within whatever the fungus is feeding on.Coenocytic hyphae where the nucleis of each cell is embedded in the cytoplasm without a cell wall. Eg. Zygomycota, OomycotaHyphae with cross wallsEg. Basidiomycota, AscomycotaHyphae without cross walls
14 Spore-producing structures Generalized Life Cycle of FungiKeyHaploid (n)- most of the life cycleHeterokaryotic (Dikaryotik=n+n)Diploid (2n)Spore-producing structuresSporesASEXUAL REPRODUCTIONMyceliumFigure 31.5 Generalized life cycle of fungi.GERMINATION
15 Spore-producing structures although the cells fusethe nuclei don't; it issaid to be dikaryoticKeyHaploid (n)Heterokaryotic stagePLASMOGAMYHeterokaryotic (n+n)different hypha attractedby pheromones fuseDiploid (2n)Spore-producing structuresfrom hours to centuriescan go by before thistakes effectKARYOGAMYSEXUAL REPRODUCTIONSporesASEXUAL REPRODUCTIONMyceliumZygoteFigure 31.5 Generalized life cycle of fungi.GERMINATION
16 Spore-producing structures KeyHaploid (n)Heterokaryotic stagePLASMOGAMYHeterokaryotic (n+n)Diploid (2n)Spore-producing structuresKARYOGAMYSEXUAL REPRODUCTIONSporesASEXUAL REPRODUCTIONMyceliumZygoteFigure 31.5 Generalized life cycle of fungi.GERMINATIONMEIOSISGERMINATIONSpores
17 Phylum Oomycota (Water Molds) 580 spp.finely branched single-celled filaments. Hyphae have multiple nuclei (Coenocytic/ aseptate)cell walls made of cellulose (like plant), not chitinreproductive cells with 2 flagella (like protists)diploid stage is dominantaquaticCause diseases such as potato blight
21 Irish Potato Famine of 19th Century Devastated potato crops, causing devastating starvation in Ireland During Ireland’s potato famine in the 19th century, over a million people died of starvation and disease. Another 1.5 million emigrated to the other countries.
22 Phylum Chyridiomycota (Chytrids) 575 spp.Appear to be link between protists and fungiaquaticSaprobes or parasitesChytrids have flagellated spores (one flagella), called zoosporesFeed on dead aquatic plants, detritus; frog parasitesForming Male GametesForming Female Gametes
24 Fungal Parasites and Pathogens The fungi Batrachochytrium dendrobatidis causes chitridiomycosisAppears to be significantly responsible for much of the worldwide decline in amphibian populationsIn 2004, an international convention of amphibian biologists announced that 32 percent of species are currently threatened, 43 percent were declining in population, and that between 9 and 122 species have become extinct since Currently, the Global Amphibian Assessment lists 427 species as "critically endangered.
25 Phylum Deuteromycota (Fungi imperfecti) > 20,000 species of fungi in 2600 genera have no known sexual stateReproduce asexually.Most belong in phylum AscomycotaCatch-all category for unclassified fungicause most fungal diseases in humansEX: ringworm, athletes foot, oral thrush and more:Pneumocystis carinii: Causes pneumonia in AIDS patients. Leading cause of death in AIDS patients. Originally classified as a protozoan.Candida albicans: Causes yeast infections of vagina in women. Opportunistic infections of mucous membranes in AIDS patients.
26 Resemble Ascomycetes, but their reproductive cycle has never been observed Different from Ascomycetes because there is a definite lack of sexual reproduction, which is why they are called Imperfect FungiPenicillium fungiUp Close
32 Phylum Zygomycota (bread molds= Zygote fungi) ~600 species currently classifiedMainly terrestrialSaprophytic molds with coenocytic hyphae (lack septa).Live in soil or on decaying organic matterAsexual Reproduction: Used most of the time.Sporangiospore: Asexual spore enclosed within a sporangium or sac at the end on an aerial hypha.Sexual Reproduction: Occurs through conjugation, the joining of hypha of two different strains (plus and minus).Zygospores: Sexual spores which are enclosed in a thick, resistant wall.Generally not pathogens.Rhizopus nigricans: Common black bread mold. May cause opportunistic infections in diabetes patients
34 Life Cycle of a Zygomycete PLASMOGAMYMating type ()Gametangia with haploid nucleiMating type ()Rhizopus growing on bread100 mYoung zygosporangium (heterokaryotic)SEXUAL REPRODUCTIONDispersal and germinationZygosporangiumFlagellumKARYOGAMYSporangiaFigure The life cycle of the zygomycete Rhizopus stolonifer (black bread mold).Diploid nucleiSporangiumASEXUAL REPRODUCTIONMEIOSISKeyDispersal and germinationHaploid (n)Heterokaryotic (n n)Mycelium50 mDiploid (2n)
35 Phylum Ascomycota (sacfungi) largest group of fungi (30,000 spp.)Molds with septate hyphae (e.g. cup fungi, morels and truffles) and some yeasts.most saprobic, live in marine, freshwater, and terrestrial habitatssome pathogens of plants (Dutch elm disease, chestnut blight, ergot).~Half live with algae as lichensSome form mycorrhizaeproduces two kinds of spores:sexual spores ascospores (inside the ascus)asexual spores conidia (naked)
36 The phylum is defined by production of sexual spores in saclike asci, usually contained in fruiting bodies called ascocarps.Ascomycetes reproduce asexually by enormous numbers of asexual spores called conidia. Conidia are not formed inside sporangia; they are produced asexually at the tips of specialized hyphae called conidiophores.
37 Truffles are round, warty, fungi that are irregular in shape Truffles are round, warty, fungi that are irregular in shape. They vary from the size of a walnut to that of a man's fist. Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods, often commanding as much as $250 to $450 per pound.Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. The female pig becomes excited when she sniffs a chemical that is similar to the male swine sex pheromone.
38 YeastsUnicellular fungi, nonfilamentous, typically oval or spherical cells.Reproduce asexually by budding or mitosis:Fission yeasts: Divide evenly to produce two new cells (Schizosaccharomyces).Budding yeasts: Divide unevenly by budding (Saccharomyces).Budding yeasts can form pseudohypha, a short chain of undetached cells.Candida albicans invade tissues through pseudohyphae.Yeasts are facultative anaerobes, which allows them to grow in a variety of environments.When oxygen is available, they carry out aerobic respiration.When oxygen is not available, they ferment carbohydrates to produce ethanol and carbon dioxide.Yeast can ferment carbohydrates. They break-down the glucose into ethanol and CO2.Used to make bread, beer and wine-Saccharomyces cerevisiae
41 Sacchromyces cerevisiae Yeast Life Cycle10 µmParent cellBudSacchromyces cerevisiaeCandida
42 LIFE CYCLE OF ASCOMYCOTA Conidia; mating type ()KeyDispersalHaploid (n)GerminationMating type ()Dikaryotic (n n)ASEXUAL REPRODUCTIONDiploid (2n)HyphaPLASMOGAMYAscus (dikaryotic)ConidiophoreMyceliaDikaryotic hyphaeMyceliumGerminationSEXUAL REPRODUCTIONKARYOGAMYDispersalDiploid nucleus (zygote)AsciEight ascosporesAscocarpFigure The life cycle of Neurospora crassa, an ascomycete.Four haploid nucleiMEIOSIS
48 Cordyceps sp.Cordyceps includes about 400 identified species and many yet to be described.All Cordyceps species are endoparasitoids, mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasitic on other fungi.25 µmantFigure 31.4 Specialized hyphaemothfly
49 Phylum Basidiomycota (club fungi) 25,000 spp.Have septate hyphae.Include mushrooms, puffballs, bracket fungi, rusts, and smuts.Sexual Reproduction: Produce basidiospores formed on club-shaped basidiaAsexual Reproduction: Through hyphae.some of them poisonous or cause plant diseases:Cryptococcus: Causes opportunistic respiratory and central nervous system infections in AIDS patients.Amanita: Mushroom produces lethal toxins to humans.Claviceps purpurea: Produces ergot toxin in wheat and rye.
50 Possess transient diploid basidium Present on gills on underside of mushroomShaped like a clubby meiosis produces basidiospores~1 billion released from a single mushroom
51 LIFE CYCLE OF BASIDIOMYCOTA Dikaryotic myceliumHaploid myceliaPLASMOGAMYMatingtype (–)Matingtype (+)SEXUALREPRODUCTIONFigure The life cycle of a mushroom-forming basidiomyceteKeyHaploid (n)LIFE CYCLE OF BASIDIOMYCOTADikaryotic (n +n)Diploid (2n)
52 Dikaryotic mycelium Haploid mycelia Mating type (–) Mating type (+) PLASMOGAMYMatingtype (–)Matingtype (+)Gills linedwith basidiaSEXUALREPRODUCTIONBasidiocarp(n+n)Basidia(n+n)Figure The life cycle of a mushroom-forming basidiomyceteKeyHaploid (n)Dikaryotic (n +n)Diploid (2n)
53 Dikaryotic mycelium Haploid mycelia Mating type (–) Mating type (+) PLASMOGAMYMatingtype (–)Matingtype (+)Gills linedwith basidiaSEXUALREPRODUCTIONBasidiocarp(n+n)Basidia(n+n)Figure The life cycle of a mushroom-forming basidiomyceteKARYOGAMYKeyHaploid (n)Dikaryotic (n +n)DiploidnucleiDiploid (2n)
54 Dikaryotic mycelium Haploid mycelia Mating type (–) Mating type (+) PLASMOGAMYMatingtype (–)Matingtype (+)Gills linedwith basidiaHaploid myceliaSEXUALREPRODUCTIONBasidiocarp(n+n)Dispersal andgerminationBasidiospores(n)Basidium withfour basidiosporesBasidia(n+n)BasidiumFigure The life cycle of a mushroom-forming basidiomyceteBasidium containingfour haploid nucleiKARYOGAMYMEIOSISKeyHaploid (n)Dikaryotic (n +n)Diploidnuclei1 µmBasidiosporeDiploid (2n)
66 · Many fungi are parasites on both plants and animals Ecological Importance of Fungi· As decomposers, fungi breakdown organic matter and release nutrients back to the environment so that they can be used again· Many fungi are parasites on both plants and animals· Many form Mutualistic relationships with other organismsLichens – association between a fungus and a green alga.Mycorrhizae – fungi that form associations with trees and plants
67 Economic importance of Fungi Yeasts ferment sugar to produce alcoholYeast through fermentation create air bubbles that causes bread to riseUnique flavors of certain cheeses are produced by fungiSoy sauce is produced by the fermentation of soy beans (via fungi)200 species of edible basidiomycetes (morels, truffles, portabella…)Penicillium sp. is used to produce penicillin, widely used antibioticCyclosporine suppress immune responses in patients receiving organ transplantsSome of the compounds produced in hospitals are used in controlled medical situations (stop uterine bleeding, treat high-blood pressure migraine head-aches)Fungi are also used as biocontrol agentOther fungi are grown commercially to produce certain chemicals (e.g., citric acid)
68 REPRODUCTION SYSTEMS IN FUNGI 1. budding2. fission3. bud fission4. sporulation- asexual spore- sexual spore (fusion of 2 nucleic)Asexual (vegetative) reproduction* Formed by the aerial hyphae of one organism. New organisms are identical to parent.Sexual (generative) reproduction* Formed by the fusion of nuclei from two opposite mating strains of the same species. New organisms are different from both parents.SEXUAL SPORESASEXUAL SPORESAscosporeBasidiosporeZygosporeOosporeSporangiosporeConidiosporeArthrospore/OidosporeKlamidospore
69 Asexual SporulationSporangiospores formed by cleavage of protoplasm in a multinucleate sporangium (Chytridiomycota, Zygomycota, Oomycota)Conidia develop directly from hyphae or from modified hyphal cells called conidiogenous cells (Ascomycota including Deuteromycetes, some Basidiomycota)
70 1. SporangiosporeSpore formed because cell protoplasm divide itself, formed small groups in sporangium pocket that placed on the tip of sporangiophore on hyphae has non septate.Ex/ Rhizopus sp.Mucor sp.Asexual spore formed within a sac (sporangium).
71 2. CONIDIOSPORE -Spore formed because the tips of hyphae split. Unicellular or multicellular spore that is not enclosed in a sac.-Spore formed because the tips of hyphae split.-Conidia formed at the tip of hyphae.-Pillar hyphae called Conidiophore.Ex/ Penicillium sp.Aspergillus sp.
72 3. ARTHROSPORESpore formed because a part of hyphae is broken & the wall thicken but not expand.ex/ GeotrichumCoccidioidesTrichosporon
73 4. CLAMIDOSPORESpore formed because part of hyphae expand & create thick wall.Rest phaseMany found at old hyphae.ex/ Candida albicansEpidermophytonThick-walled spore formed within a hyphal segment.
74 5. BLASTOSPORESpore which created from budding on yeast cell & the bud not liberated from its motherex/ Rhodotorula sp.Blastomyces dermatitidis
75 Sexual Sporulation 1. ASCOSPORE One-cell spore formed inside a pocket called ascusex/ Saccharomyces
76 2. BASIDIOSPORESpore producted by basidia. Basidium exist on the tip of hyphae expanding that formed like vase/clubex/ Cryptococcus neoformans
77 3. ZYGOSPORE Big thick-walled spore that formed if the tip of two swollen hyphae(gametangia) fuse(merged)ex/ RhizopusMucor
78 4. OOSPORE Spore that formed inside oogonium because female gamet (oospher)fertilized by male gamet(antheredium) oosporeInside each oogoniumexist > 1 oospher
79 Question: What is the largest living thing on Earth?
81 A Giant Fungus!Strange but True: The Largest Organism on Earth is a FungusWhat is probably the largest living organism on earth has been discovered in the Malheur National Forest in eastern Oregon. A fungus living three feet underground is estimated to cover 2,200 acres. After testing samples from various locations, scientists say it is all one organism.Officially known as Armillaria ostoyae, or the honey mushroom, the fungus is 3.5 miles across and cover 2200 acres (takes up 1665 football fields).The small mushrooms visible above ground are only the tip of the iceberg.Experts estimate that the giant mushroom is at least 2400 years old, but could be 7200 years old.Aerial view of smaller forest patches infected by Armillaria in Montana1 acre=4.046,86 m²= ~4 dönüm2200 acre= m²1 mil=1,6 km3.5 mil= 5,4 km
84 Cellulose cell walls, 2N hyphae Flagellated oospores from sporangia PhylumEx’sCharacteristicsAsexualSexualOomycotaMildewSpud blightCellulose cell walls, 2N hyphaeFlagellated oospores from sporangiaGametes fuse in gametangia creating oosporesZygomycotaRhizopus a dung fungusChitin cell wallsCoenocytic = hyphae lack crosswallsUnflagel. spores drop from sporangiaGametangia fuse to create zygosporeAscomycotaYeast, morels, trufflesConidia on conidophoresHyphae + & - fuse to create ascospores in ascusBasidiomycotaMushrooms Puffballs, rusts, smutsCross walls in hyphaeAsexual by way of Conidophores which produce conidiosporesSexual when hyphae fuse in BASIDIA to producebasidiosporesDeuteromycotaPenicillium,Athlete’s Foot fungus,Tomato BlightSimilar toBasidio andZygomyAsexual by conidia which produce conidophoresSexual reproNot known