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Definitions

Definitions. Mycologists --scientists who study fungi Mycology- -scientific discipline dealing with fungi Mycoses --diseases caused in animals by fungi . What is a fungus? .

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Definitions

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  1. Definitions • Mycologists--scientists who study fungi • Mycology--scientific discipline dealing with fungi • Mycoses--diseases caused in animals by fungi

  2. What is a fungus? • A eukaryotic, heterotrophic organism devoid of chlorophyll that obtains its nutrients by absorption, and reproduces by spores. • The primary carbohydrate storage product of fungi is glycogen. • Most fungi have a thallus composed of hyphae (sing. hypha) that elongate by tip growth

  3. The fungal thallus consists of hyphae; a mass of hyphae is a mycelium.

  4. Structure of fungi

  5. The Characteristics of Fungi • Fungi are NOT plants • Hyphae = tubular units of construction • Heterotrophic by absorption • Reproduce by spores • Ecologically pivotal roles

  6. Tubular Hard wall of chitin Cross walls may form compartments (± cells) Multinucleate Grow at tips Hyphae

  7. Heterotrophic by Absorption • Fungi get carbon from organic sources • Hyphal tips release enzymes • Enzymatic breakdown of substrate • Products diffuse back into hyphae Enzymatic breakdown Nucleus hangs back and “directs” Products Enzymes Product diffuses back into hypha and is used

  8. Modifications of hyphae

  9. Hyphal growth • Hyphae grow from their tips • Mycelium = extensive, feeding web of hyphae • Mycelia are the ecologically active bodies of fungi This wall is rigid Only the tip wall is plastic and stretches

  10. Hyphal growth from spore germinating spore mycelium

  11. Reproduce by spores • Spores are reproductive cells • Sexual • Asexual • Formed: • Directly on hyphae • Inside sporangia • Fruiting bodies Pilobolus sporangia Penicillium hyphae Amanita fruiting body

  12. Fungi are ancient • Major fungal lineages are ancient, perhaps emerging one billion years ago • Fungi were present before the emergence of animals and vascular plants

  13. Old and Modern Classification • Carl Linnaeus (1707-1778) the “Father of Taxonomy” • “ Minerals exist; plants exist and live; animals exist, live and sense.” • Plants without obvious sexual organs were classified in Class Cryptogamia (lichens, fungi, mosses, ferns) • Fungi are primitive (asli) plants under this classification of organisms.

  14. Old Classification The Five kingdom system • Eukarya (includes all organism with a nucleus & membrane bound organelles) • Plants and Animals are fairly obvious (ketara) • Fungi, are very distinct (berlainan) from the other kingdoms • Kingdom Protista is a “dumping ground” for organisms that don’t fit into the other eukaryotic kingdoms (Whittaker, 1969)

  15. Modern Classification • At least 7 kingdoms are now recognized: • Eubacteria, Archaebacteria, Animalia, Plantae, Eumycota, Stramenopila (Chromista), Protoctista (Protozoa, Protista)

  16. Systems of classifying fungi 1) 1860 HOGG proposed the term PROTOCTISTA - fungi and neither Plant or Animal. This kingdom composed mostly of unicellular organisms. The kingdom was later replaced by 2 kingdoms – MYCOTA & MONERA (prokaryotes) and PROTOCTISTA(eukaryotes). 2) 1947 Microscopes enable study of complex structural characteristics. New classification (WOLF & WOLF, 1947) 3) 1969 Fungi in its own kingdom by WHITTAKER – FUNGI KINGDOM.

  17. Systems of classifying fungi 4) 1998 Modification by MARGUILIS & SCHWARTZ – used characteristics (structure & function). • MONERA: Prokaryotes – bacteria, actinomycetes, blue-green algae. • PROTOCTISTA: Eukaryotes – protozoa and other unicellular and colonial organisms such as water moulds, slime moulds and slime nets. • FUNGI : Eukaryotes – organisms that lack flagella that develop from spores such as yeast, molds, rusts and mushrooms. • PLANTAE: Eukaryotes – organisms that develop from embryos such as liverworts, mosses and vascular plants. • ANIMALIA: Eukaryotes – organisms that develop from a blastula (hollow ball of cells) such a sponges, worms, arthropods and mammals.

  18. MARGUILIS & SCHWARTZ(1998) Classify the fungi into 3 phyla : Zygomycota, Ascomycota and Basidiomycota. Chytrids (CHYTRIDIOMYCOTA) in the Kingdom Proctista. Deuteromycota with their closest relatives that are the Ascomycota and Basidiomycota. Lichen with the Phylum Ascomycota.

  19. Other classifications MOORE, 1998 (quoted from Pfieffer, M., et al., 2001) states that plants, animals and fungi can be separated based on how they obtain energy. Plants possess (memiliki) chloroplasts as photosynthetic structures used to produce food. Animals possess mitochondria used for internalized digestion. Fungi excrete enzymes into the food source they live within external digestion.

  20. Classification using molecular research techniques BALDAUF & PALMER (1993), WAINWRIGHT et al. (1993) and HASEGAWA et al (1993) The above current schemes agree that the three major kingdoms are separated and thereby confirmed that there are no connection between the fungi-plant kingdom.

  21. KINGDOM CHARACTERISTIC EXAMPLE Monera Prokaryocyte Bacteria Actinomyces Protista Eukaryocyte Protozoa Eukaryocyte * Fungi Fungi Plants Eukaryocyte Plants Moss Animals Eukaryocyte * Arthropods Mammals Man

  22. Question 2 Fill in the blanks of the systematic of classification 1) Kingdom 2) Division / Phylum 3) ___________ 4) Order 5) ___________ 6) Tribe 7) ___________ 8) Species • Sometimes there are subdivisions and subclasses

  23. Hierarchical Classification Kingdom Fungi Phylum Basidiomycota Class Basidiomycetes Order Agaricales Family Agaricaceae Genus Agaricus Species: Agaricus campestris L.

  24. Fungus versus Fungi • “Fungus” is used inclusively for a heterogenous group of organisms that have traditionally been studied by mycologists • “Fungi” refers to the organisms in the Kingdom Fungi, the true fungi, also called the “Eumycota”

  25. How are fungi named? • To determine the correct name for a taxon, certain steps must be followed, including: • Effective publication • Valid publication • Description or diagnosis in Latin • Clear indication of rank • Designated type

  26. Nomenclature • Nomenclature: the “allocation (pemberian bahagian) of scientific names to the units a systematist considers to merit formal recognition.” (Hawksworth et al., 1995. The Dictionary of the Fungi).  • The nomenclature of fungi is governed by the International Code for Botanical Nomenclature, as adopted by the International Botanical Congress.

  27. How many species of fungi exist? - 80,000 species of fungi described - 1,700 new species described each year

  28. How many species of fungi exist? - 80,000 species of fungi described - 1,700 new species described each year

  29. Reasons why it is not easy to classify fungi Fungi comprise (mengandungi) of a broad number of organisms. Fungi have various forms depending on the environment and conditions in which they grow. Many terms being used to describe the morphological structures of fungi.

  30. Basic Characteristics and Life Cycles • Ascomycota (inc.Deuteromycetes) • Basidiomycota • Zygomycota • Mitosporic Fungi (Fungi Imperfecti)

  31. Ascomycota – “sac fungi” • Teleomorphic fungi • Produce sexual and asexual spores • Sex. – asci • Asex. – common • Cup fungi, morels, truffles • Important plant parasites & saprobes • Yeast - Saccharomyces • Septate • Most lichens A cluster of asci with spores inside

  32. Basidiomycota – “club fungi” • Produce basidiospores and sometimes conidiospores • Sex – basidia • Asex – not so common • Long-lived dikaryotic mycelia • Rusts & smuts – primitive plant parasites • Septate • Mushrooms, polypores, puffballs • Enzymes decompose wood • Mycorrhizas SEM of basidia and spores

  33. Zygomycota – “zygote fungi” • Conjugation fungi • Coenocytic • Sex - zygosporangia • Asex - common • Produce sporangiospores and zygospores • Hyphae have no cross walls • Grow rapidly • Rhizopus, Mucor (opportunistic, systemic mycoses) • Mycorrhizas Fig 31.6 Rhizopus on strawberries

  34. True Fungi • Chytridiomycota – “chytrids”- Classified in CMR as true fungi (because of their molecular relationships) • Simple fungi • Produce motile spores • Mostly saprobes and parasites in aquatic habitats • Could just as well be Protists Fig 31.5 Chytridium growing on spores

  35. True Fungi versus Slime Moulds True fungi: • those that are hyphal • possess cell walls throughout most of their life cycle • are exclusively absorptive in their nutrition. Slime moulds: - those that do not form hyphae - lack cell walls during the phase that they obtain nutrients and grow • are capable of ingesting nutrients by phagocytosis. So they are more common to Protista although they produce fruiting bodies like fungi. • The most studied of them are the cellular slime moulds and theplasmodialslime moulds or Myxomycetes.

  36. QUESTION The fungus can never be classified in Plantae or Animalia? EXPLAIN WHY? (Hint ! LOOK AT ITS MOBILITY & NUTRITION)

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