CLASSIFICATION_AND_GENERAL STRUCTURES OF FUNGI.ppt

CLASSIFICATION and GENERAL STRUCTURE of FUNGI YEDİTEPE UNIVESITY SCHOOL of MEDICINE 2023 Nilgün Çerikçioğlu YEDİTEPE ALL THE BIOLOGICAL TERMS AND BEHAVIORS ARE OF MEDICAL IMPORTANCE  GENERAL CHARACTERISTICS OF FUNGI Fungi (plural), fungus (singular)  Mycology The study of fungi  More than...

CLASSIFICATION and GENERAL STRUCTURE of FUNGI YEDİTEPE UNIVESITY SCHOOL of MEDICINE 2023 Nilgün Çerikçioğlu YEDİTEPE ALL THE BIOLOGICAL TERMS AND BEHAVIORS ARE OF MEDICAL IMPORTANCE  GENERAL CHARACTERISTICS OF FUNGI Fungi (plural), fungus (singular)  Mycology The study of fungi  More than 150.000 species, identified   Only 300 species produce disease in man and animals About a dozen (12..) spp:  cause 90% of all fungal diseases   •All: EUKARYOTIC •Mostly possess: Rigid CELL WALL •Some are: motile (flagellated) (not related to humans) •NO photosynthesis •Chemotrophic (degrade organic substances) •Optimal pH : 2,2 – 9,6 (molds) 3,0 – 7,5 (yeasts) GROWTH FORMS OF FUNGI (MORPHOLOGY) • 1) • • • MOLDS Large multicellular aggregates of long branching filaments (hyphae) Hyphae: filaments = mycelium Responsible for the fluffy appearance of mold colony Colored Spores Hyphae Hyphae an colored spores Hyphae Germinating Mold Spore (germ tube ) spore germ tube Initial stage (phase) of hypha Spore Germination and Hyphae Production Under microscope field branching According to shape i) Septate hyphae: Filaments - Septa have PORES (flow of cytoplasm and organelles) ii) Aseptate hyphae: No cross walls (Coenocytic hyphae)  Septate hyphae According to functions: i)Vegetative Hyphae: - actively growing hyphae (into the medium) • ii) Aerial Hyphae: to pigmented) *Some Aerial hyphal cells reproductive spores (melanin -(reproductive hyphae ) carry reproductive spores - project above the surface into the air - contribute the fluffy appearance of the mold colony turn Aerial Vegetative Aerial hyphae/ reproductive spores Spores (pigmented) Hyphae • • • • Molds grow at 20 – 260C (room temperature) Rate of growth : - saprophitic molds in 2 – 5 days - pathogenic molds in 2 – 4 weeks Topography of the colony: - glabrous - velvety - verrucose - cottony - powdery True Pigmentation - reverse site - some: diffusible **( nonpigmented / nonmelanized hyaline hyphae) Hyaline moulds are fungi that grow predominantly in a filamentous form with colourless hyphae Their spores may be pigmented (black, green..) Septate hyaline hyphae from an infected nail (40x) Dark pigmented hyphae (40x) Mold colony (fluffy appearence ) Pigmented spore Hyaline Hyphae MOLD REPRODUCTIVE SPORES ASEXUAL..........................................SEXUAL • Mostly produced at the ends of aerial hyphae -Hyphal cell transforme into spores - Resistant to unfavourable conditions (protection) - Produced in large numbers (reproduction) - Easily disseminated in nature, in laboratory conditions, in hospital (dissemination) ASEXUAL SPORES DIVIDE INTO TWO MAJOR GROUPS: CONIDIA SPORANGIOSPORES CONIDIA divide into four groups: İ) Chlamydospores *** Their appearence on specific media serve as a first criterion for fungal genus and species identification ii) Arthroconidium ….disease transmision iii) Microconididium…disease transmision iv) Macroconidium***….. Their appearence on specific media serve as a first criterion for fungal genus and species identification A) Conidia (conidium) • Form clusters at the end of aerial hyphae • Light weight, easily disseminated (enhancing spread of fungus) i) Chlamydoconidia - Large, round, thick walled, unicellular structure - Contains: glycogen or lipid energy reserves - Unicellular IDENTIFICATION UNDER MICROSCOPE FIELD ii) Arthroconidia • Hyphal cells undergo thickening of their cell – walls • Fragment away from mother filament, • Forming: Barrel shaped conidia • Easily aerosolized !!! iii) Microconidia • Unicellular • Small spores iv) Macroconidia (typical appearance ) • Multicellular • USEFUL IN IDENTIFICATION UNDER MICROSCOPE FIELD( name of the mold!!!!! )  microco nidia arthroc onidia macroco nidia chlamydo conidia B) • Sporangiospores • Borne at the and of aerial hyphae Sac like structures (sporangium) Contain: sporangiospores Sac ruptures mature spores discharge • Molds with aseptate hyphae grow. • • Black Bread Mold Disease Transmission RUPTURED SPORANGIUM with sporangiospores Teen, 14, died after catching rare fungal infection from breathing in mould / SUMMARY SEXUAL SPORE IN MOLDS  Zygospor  In: ASEPTATE HYPHAL MOLDS Zygospores Mold spores are important for human health 2) YEASTS (BLASTOSPORES / BLASTOCONIDIA)) • • • • • • Large, single (unicellular) cells 5 – 8 m (diameter) (cocci 0.2-2.0 µm) Spherical or ellipsoidal Most reproduce by budding (Bud: blastospore) (ASEXUAL) Bud (daughter cell ) breaks away from mother cell New buds may develop Bud, daughter cell Mother yeast cell SIZES OF YEASTS 2-10 μm (spherical) (Average) 20-30 μm (cylindrical) Larger than cocci (0.5- 2 μm) MOTHER YEAST BUD •If single buds fail to separate from the mother;  chains of buds are formed ,  become elongated ,  pseudohyphae are produced  (mistaken for the true hyphae of molds under microscope field)) Budding yeasts Pseudohyphae and buds in clinical sample Budding yeasts and pseudohyphae in patient’s urine sample • Some yeasts produce additional specific structures!!!**************** - Germ tube formation: (dimorphism) * A short, hypha – like structure … *May turn into Long / branching true hyphae (as happening in the molds) (yeast – to – true hyphae transition) * Germ tubes (initial step for true hyphae production) Elongated buding yeasts Budding yeasts Pseudohyphae, and budding yeasts Constrictions between the elongated buds True hyphae Budding yeasts Deep Tissue section • • • Yeasts grow best at 300 – 370C Produce : colonies on solid media (as bacteria ) Colonies: cream – colored (pink, red, occasionally) BLASTOSPORES =BUDS= YEASTS and HYPHAL FORMS OF YEASTS ARE: ...ASEXUAL**** Sexual Spores of Yeasts  Basidiospores:  Some yeasts can produce in nature and in tissue  MOLDS DO NOT PRODUCE!! Basidiospores of yeasts • SEXUAL REPRODUCTİON COMMON İN YEAST / MOLDS (ASCOSPORES) Diploid yeast cells and some molds can produce Ascus / Ascospores • • *Ascus (sac) ruptures are released ascospores Ascus and ascospores in tissue MONOMORPHISM (monomorphic fungi)  Fungi grow ONLY in yeast or mold morphology (monomorphic fungi) DIMORPHISM (dimorphic fungi ) VIRULENCE FACTOR ADAPTATION******) Many species of fungi grow in mold / hyphal / or yeast form According to conditions (temperature, nutrients, CO2 concentration, pH)… (FOR • • e.g: mold yeast e.g: yeast true hyphae [Candida albicans true septate hyphae] SUBCELLULAR STRUCTURE OF FUNGI *Cell Wall / Slime (the outer most layers) *Cell membrane (under the cell wall) *Cytoplasmic content All are medically important!!!!! slime-biofılm Almost all the fungi produce slime / biofilm In tissue On biomaterials Yeast CAPSULE Capsule Cell Wall Chitin N- acetyl - glucosamin polymers Glucan: glucose polimer Mannan: mannose polimer • Antigenic (polysaccharides) • Responsible from: attachement to human cells (mannan) • Glucan Target for antifungal drugs !!!(glucan) Cell Membrane • • • • • Bilayer membrane Phospholipids + proteins Fungal membrane also contains STEROLS Mainly in: ergosterol form Target for antifungal drugs.!!! Cytoplasmic content • Several nuclei • Endoplasmic reticulum Mitochondria Ribosomes (80s) (60 + 40) Golgi apparatus • Plasmids Fungal viruses • Secondary metabolites. - Mycotoxins (Carcinogens) (aflatoxin) - Anticancer substances - Pharmacologic compounds (penicillin ) CLASSIFICATION AND GENERAL CHARACTERISTICS OF FUNGI 1- CLASSIFICATION OF FUNGI • Classification according to: - sexual spore types - morphology of hyphae • Oomycotina Zygomycota sexual and asexual Ascomycota cycles Basidiomycota Deutoromycota Only asexual cycle. (Fungi imperfecti) a) OOMYCOTA (CHROMYSTA) • Water molds (not human related)************ Produce flagellated (motile) sexual oospores • • • • Mostly: unicellular Have NO cell wall !!! Not associated with humans b) ZYGOMYCOTA • • • Characterized by: aseptate fungi Asexual : sporangiospores Sexual: Zygospores Include – black bread mold (Rhizopus nigricans) zygospore c) ASCOMYCOTA • • • Sexual: ascospores Produced by: molds / Some Yeasts The largest fungal groups (e.g. Penicillium, Aspergillus, Candida..) Some fungi produce ascospores in tissue during infection d) BASIDIOMYCOTA (some yeasts) • Mostly produce sexual spores (basidiospores) • İnfection: acquired through inhalation of basidiospores or desiccated yeast cells from the environment. basidiospore e) DEUTOROMYCOTA • (fungi Imperfecti) Have NO sexual cycle e.g: Some Candida species