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)
3 genera, 50 spp. Vegetative thallus – amoeboid cells that aggregate to form pseudoplasmodium produce walled spores during reproduction Cellular slime molds contain cellulose in their spore wall widespread in forest soils, dung, decaying plant matter Feed on bacteria in soil as amoeboid cells without flagella Phylum Acrasiomycota (Cellular slime molds)
Cellular Slime Molds Life Cycle
71 genera, 500 spp. vegetative thallus – plasmodium nucleus replicates without dividing to form multinucleated feeding mass do not contain cellulose may contain 2 flagella in reproductive cells only Phylum Myxomycota (Plasmodial slime molds, True slime molds) Fuligo septica
KINGDOM FUNGI (TRUE MOLDS, EUMYCOTA)
u 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. uOver 100,000 fungal species identified. It is estimated there are actually 1.5 million species of fungi u Only about 100 are human or animal pathogens. – Most human fungal infections occur in immunocompromised individuals (opportunistic infections). u Fungal diseases in plants cause over 1 billion dollars/year in losses. u Multicellular, but yeasts are unicellular. u Most are aerobes or facultative anaerobes. u Cell walls are made up of chitin (polysaccharide). uReproduce sexually and asexually – Asexually by spores – Sexually by mating of hyphae filaments from two genetically different fungi u Fungi are classified by the shape of their sporangium and the way they produce sexual spores. GENERAL CHARACTERISTICS OF FUNGI
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 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. Hyphae without cross walls
Key Haploid (n)- most of the life cycle Heterokaryotic (Dikaryotik=n+n) Diploid (2n) Spores Spore-producing structures ASEXUAL REPRODUCTION GERMINATION Mycelium Generalized Life Cycle of Fungi
PLASMOGAMY Key Haploid (n) Heterokaryotic (n+n) Diploid (2n) Spores Spore-producing structures ASEXUAL REPRODUCTION SEXUAL REPRODUCTION GERMINATION Zygote Heterokaryotic stage KARYOGAMY Mycelium although the cells fuse the nuclei don't; it is said to be dikaryotic different hypha attracted by pheromones fuse from hours to centuries can go by before this takes effect
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 chitin reproductive cells with 2 flagella (like protists) diploid stage is dominant aquatic Cause diseases such as potato blight
LIFE CYCLE OF OOMYCOTA Oogonia
e.g. water molds (saprobes or parasites of fish)
Irish Potato Famine of 19 th 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.
575 spp. Appear to be link between protists and fungi aquatic Saprobes or parasites Chytrids have flagellated spores (one flagella), called zoospores Feed on dead aquatic plants, detritus; frog parasites Phylum Chyridiomycota (Chytrids) Forming Male Gametes Forming Female Gametes
Fungal Parasites and Pathogens The fungi Batrachochytrium dendrobatidis causes chitridiomycosis Appears to be significantly responsible for much of the worldwide decline in amphibian populations In 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.
u> 20,000 species of fungi in 2600 genera have no known sexual state uReproduce asexually. uMost belong in phylum Ascomycota u Catch-all category for unclassified fungi ucause most fungal diseases in humans EX: 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. Phylum Deuteromycota (Fungi imperfecti)
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 Fungi Penicillium fungi Up Close
Opportunistic Infection by Candida albicans in an AIDS Patient Source: Atlas of Clinical Oral Pathology, 1999
Severe nail infection with Trichophyton rubrum in a 37-year-old male AIDS patient. Source: Intern. J. Dermatol. 31(1992): 453.
u~600 species currently classified uMainly terrestrial uSaprophytic molds with coenocytic hyphae (lack septa). uLive in soil or on decaying organic matter uAsexual Reproduction: Used most of the time. Sporangiospore: Asexual spore enclosed within a sporangium or sac at the end on an aerial hypha. uSexual 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. u Generally not pathogens. – Rhizopus nigricans: Common black bread mold. May cause opportunistic infections in diabetes patients Phylum Zygomycota (bread molds= Zygote fungi)
Rhizopus growing on bread Flagellum Mating type ( ) Mating type ( ) Gametangia with haploid nuclei Young zygosporangium (heterokaryotic) PLASMOGAMY 100 m 50 m Zygosporangium KARYOGAMY SEXUAL REPRODUCTION Diploid nuclei Key Haploid (n) Diploid (2n) Heterokaryotic (n n) Sporangium MEIOSIS Dispersal and germination ASEXUAL REPRODUCTION Mycelium Sporangia Life Cycle of a Zygomycete
ulargest group of fungi (30,000 spp.) uMolds with septate hyphae (e.g. cup fungi, morels and truffles) and some yeasts. umost saprobic, live in marine, freshwater, and terrestrial habitats usome pathogens of plants (Dutch elm disease, chestnut blight, ergot). u~Half live with algae as lichens uSome form mycorrhizae uproduces two kinds of spores: – sexual spores ascospores (inside the ascus) – asexual spores conidia (naked) Phylum Ascomycota (sacfungi)
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.
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.
Yeasts uUnicellular fungi, nonfilamentous, typically oval or spherical cells. uReproduce 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. uYeasts 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. uYeast can ferment carbohydrates. They break-down the glucose into ethanol and CO 2. Used to make bread, beer and wine -Saccharomyces cerevisiae
Conidia; mating type ( ) Mating type ( ) Dispersal Germination ASEXUAL REPRODUCTION Hypha Conidiophore Mycelium Germination Ascocarp Dispersal Asci Mycelia Eight ascospores SEXUAL REPRODUCTION Four haploid nuclei MEIOSIS Diploid nucleus (zygote) KARYOGAMY Dikaryotic hyphae Ascus (dikaryotic) PLASMOGAMY Key Haploid (n) Diploid (2n) Dikaryotic (n n) LIFE CYCLE OF ASCOMYCOTA
Tuber sp. (Truffle)
Ophiostoma ulmi (causes Dutch elm disease)
25 µm Cordyceps sp. fly moth ant 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.
u25,000 spp. uHave septate hyphae. uInclude mushrooms, puffballs, bracket fungi, rusts, and smuts. uSexual Reproduction: Produce basidiospores formed on club- shaped basidia u Asexual Reproduction: Through hyphae. u 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. Phylum Basidiomycota (club fungi)
Possess transient diploid basidium – Present on gills on underside of mushroom – Shaped like a club – by meiosis produces basidiospores – ~1 billion released from a single mushroom
SEXUAL REPRODUCTION Diploid (2n) Haploid (n) Dikaryotic (n +n) Key PLASMOGAMY Mating type (+) Haploid mycelia Dikaryotic mycelium Mating type (–) LIFE CYCLE OF BASIDIOMYCOTA
SEXUAL REPRODUCTION Diploid (2n) Haploid (n) Dikaryotic (n +n) Key PLASMOGAMY Mating type (+) Haploid mycelia Dikaryotic mycelium Mating type (–) Basidia (n+n) Gills lined with basidia Basidiocarp (n+n)
SEXUAL REPRODUCTION Diploid (2n) Haploid (n) Dikaryotic (n +n) Key PLASMOGAMY Mating type (+) Haploid mycelia Dikaryotic mycelium Mating type (–) Basidia (n+n) Gills lined with basidia Basidiocarp (n+n) KARYOGAMY Diploid nuclei
Basidium SEXUAL REPRODUCTION Diploid (2n) Haploid (n) Dikaryotic (n +n) Key PLASMOGAMY Mating type (+) Haploid mycelia Dikaryotic mycelium Mating type (–) Basidia (n+n) Gills lined with basidia Basidiocarp (n+n) KARYOGAMY Diploid nuclei MEIOSIS Basidium containing four haploid nuclei Dispersal and germination Basidiospores (n) Basidium with four basidiospores Basidiospore 1 µm Haploid mycelia
Lycoperdon sp. (puffball)
Puffballs emitting spores 70 trillion!
Trametes versicolor (Bracket fungus)
Geastrum triplex (Earth star fungus)
Clavaria zollingeri (Coral fungus)
Wheat leaf rust on wheat Puccinia sp. (Rust fungi)
Ustilago sp. (Smut 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 organisms Lichens – association between a fungus and a green alga. Mycorrhizae – fungi that form associations with trees and plants Ecological Importance of Fungi
Yeasts ferment sugar to produce alcohol Yeast through fermentation create air bubbles that causes bread to rise Unique flavors of certain cheeses are produced by fungi Soy 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 antibiotic Cyclosporine suppress immune responses in patients receiving organ transplants Some 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 agent Other fungi are grown commercially to produce certain chemicals (e.g., citric acid) Economic importance of Fungi
REPRODUCTION SYSTEMS IN FUNGI 1. budding 2. fission 3. bud fission 4. sporulation - asexual spore - sexual spore (fusion of 2 nucleic) Asexual (vegetative) reproduction Sexual (generative) reproduction Sporangiospore Conidiospore Arthrospore/Oidospore Klamidospore Ascospore Basidiospore Zygospore Oospore ASEXUAL SPORES SEXUAL SPORES * Formed by the aerial hyphae of one organism. New organisms are identical to parent. * Formed by the fusion of nuclei from two opposite mating strains of the same species. New organisms are different from both parents.
Asexual Sporulation Sporangiospores 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)
1. Sporangiospore Spore 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).
2. CONIDIOSPORE -Spore formed because the tips of hyphae split. -Conidia formed at the tip of hyphae. -Pillar hyphae called Conidiophore. Ex/ Penicillium sp. Aspergillus sp. Unicellular or multicellular spore that is not enclosed in a sac.
3. ARTHROSPORE Spore formed because a part of hyphae is broken & the wall thicken but not expand. ex/ Geotrichum Coccidioides Trichosporon
4. CLAMIDOSPORE Spore formed because part of hyphae expand & create thick wall. Rest phase Many found at old hyphae. ex/ Candida albicans Epidermophyton Thick-walled spore formed within a hyphal segment.
5. BLASTOSPORE Spore which created from budding on yeast cell & the bud not liberated from its mother ex/ Rhodotorula sp. Blastomyces dermatitidis
1. ASCOSPORE One-cell spore formed inside a pocket called ascus ex/ Saccharomyces Sexual Sporulation
2. BASIDIOSPORE Spore producted by basidia. Basidium exist on the tip of hyphae expanding that formed like vase/club ex/ Cryptococcus neoformans
3. ZYGOSPORE Big thick-walled spore that formed if the tip of two swollen hyphae (gametangia) fuse (merged) ex/ Rhizopus Mucor
4. OOSPORE Spore that formed inside oogonium because female gamet (oospher) fertilized by male gamet (antheredium) oospore Inside each oogonium exist > 1 oospher
Question: Question: What is the largest living thing on Earth?
A Giant Fungus! What 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 Montana 1 acre=4.046,86 m²= ~4 dönüm 2200 acre= m² 1 mil=1,6 km 3.5 mil= 5,4 km Strange but True: The Largest Organism on Earth is a Fungus
A Brief Summary
PhylumEx’sCharacteristicsAsexualSexual OomycotaMildew Spud blight Cellulose cell walls, 2N hyphae Flagellated oospores from sporangia Gametes fuse in gametangia creating oospores ZygomycotaRhizopus a dung fungus Chitin cell walls Coenocytic = hyphae lack crosswalls Unflagel. spores drop from sporangia Gametangia fuse to create zygospore AscomycotaYeast, morels, truffles Conidia on conidophores Hyphae + & - fuse to create ascospores in ascus BasidiomycotaMushrooms Puffballs, rusts, smuts Cross walls in hyphae Asexual by way of Conidophores which produce conidiospores Sexual when hyphae fuse in BASIDIA to produce basidiospores DeuteromycotaPenicillium, Athlete’s Foot fungus, Tomato Blight Similar to Basidio and Zygomy Asexual by conidia which produce conidophores Sexual repro Not known