GENERAL CHARACTERISTICS OF FUNGI DOÇ.DR.HRİSİ BAHAR.

GENERAL CHARACTERISTICS

OF FUNGI DOÇ.DR.HRİSİ BAHAR

Fungi

Fungi are NOTNOT plants Nonphotosynthetic Eukaryotes Nonmotile Most are saprobessaprobes (live on dead organisms)

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Absorptive heterotrophsAbsorptive heterotrophs (digest food first & then absorb it into their bodies

Release digestive enzymesdigestive enzymes to break down organic

material or their host Store food energy as

glycogenglycogenBREAD MOLDBREAD MOLD

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Important decomposers & recyclers of nutrients in the environment

Most are multicellular, except unicellular yeast

Lack true roots, stems or leaves

MULTICELLULAR MULTICELLULAR MUSHROOMMUSHROOM

UNICELLULAR YEASTUNICELLULAR YEAST

Cell walls are made of chitin (complex polysaccharide)

Body is called the Thallus

Grow as microscopic tubes or filaments called hyphae

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Some are edible, while others are poisonous

EDIBLEEDIBLE POISONOUSPOISONOUS 77

Produce both sexual and asexual spores

Classified by their sexual reproductive structures

Spores come Spores come in various in various

shapesshapes88

Grow best in warm, moist environments

Mycology is the study of fungi

Mycologists study fungi A fungicide is a chemical

used to kill fungi

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Fungi include puffballs, yeasts, mushrooms, toadstools, rusts, smuts, ringworm, and molds

The antibiotic penicillin is made by the Penicillium mold

Penicillium moldPenicillium mold

PuffballPuffball 1010

Vegetative StructuresVegetative Structures

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TubularTubular shape ONEONE continuous

cell Filled with

cytoplasm & cytoplasm & nucleinuclei

MultinucleateMultinucleate Hard cell wall of

chitinchitin1212

StolonsStolons – horizontal hyphae that connect groups of hyphae to each other

RhizoidsRhizoids – rootlike parts of hyphae that anchor the fungus

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STOLONSTOLON

RHIZOIDSRHIZOIDS

Cross-walls called SEPTA may form compartments

Septa have pores for movement of cytoplasm

Form network called mycelia that run through the thallus (body)

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Hyphae grow from their tips Mycelium is an extensive,

feeding part of hyphae Mycelia are the ecologically

active bodies of fungi

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ABSORPTIVE ABSORPTIVE HETEROTROPHHETEROTROPH

Fungi get carbon from organic sources

Tips of Hyphae release enzymes Enzymatic breakdown of substrate Products diffuse back into hyphae

Digested material is then used by the hyphae

Nucleus “directs” the digestive process

Fungi may be classified based on cell division (with or without cytokinesis) Aseptate or coenocytic (without

septa) Septate (with septa)

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NO CROSS NO CROSS WALLSWALLS CROSS CROSS

WALLSWALLS

RReproductive Cultureeproductive Culture

ASEXUAL & SEXUAL SPORESASEXUAL & SEXUAL SPORES

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REPRODUCTIONREPRODUCTION

Most fungi reproduce AsexuallyAsexually and SexuallySexually by spores

ASEXUALASEXUAL reproduction is most most common common method & produces genetically identical genetically identical organisms

Fungi reproduce SEXUALLYSEXUALLY when conditions are poor & conditions are poor & nutrients nutrients are are scarcescarce

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SPORESSPORES

Spores are an adaptationadaptation to life on land

Ensure that the species will disperse species will disperse to new locationsto new locations

Each spore contains a reproductive reproductive cellcell that forms a new organism

NonmotileNonmotile Dispersed by windwind

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SEXUAL REPRODUCTIONSEXUAL REPRODUCTION Used when environmental Used when environmental

conditions are poor conditions are poor (lack (lack of nutrients, space, of nutrients, space, moisture…)moisture…)

No male or female fungiNo male or female fungi Some fungi show Some fungi show

dimorphismdimorphism May grow as May grow as MYCELIA MYCELIA

or aor a YEAST –LIKE YEAST –LIKE state state (Filament at 25(Filament at 25ooC & C & Round at 37Round at 37ooC)C)

2121Dimorphic FungiDimorphic Fungi

SEXUAL REPRODUCTIONSEXUAL REPRODUCTION Haploid 1n hyphae 1n hyphae from 2 mating types (+ 2 mating types (+

and -) FUSE and -) FUSE (Fertilization)(Fertilization) Forms aForms a hyphae with hyphae with 2 nuclei that 2 nuclei that

becomes a ZYGOTEbecomes a ZYGOTE The zygote divides to make a The zygote divides to make a SPORESPORE

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SPORE FORMSSPORE FORMS

THREE TYPES OF ASEXUAL REPRODUCTIONTHREE TYPES OF ASEXUAL REPRODUCTION

FragmentationFragmentation – part of the mycelium becomes separated & begins a life of its own

BuddingBudding – a small cell forms & gets pinched off as it grows to full size Used by yeasts Used by yeasts

Asexual spores Asexual spores – production of spores by – production of spores by a single myceliuma single mycelium

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Spores may be Formed: Directly on hyphae Inside sporangia On Fruiting bodies

Amanita fruiting body Pilobolus sporangia

Penicillium hyphae

Fruiting Bodies Fruiting Bodies are modified as hyphae that make asexualasexual spores

An upright stalk called the SporangiosphoreSporangiosphore supports the spore case or SporangiumSporangium

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Types of Fruiting Types of Fruiting Bodies:Bodies: BasidiaBasidia SporangiaSporangia AscusAscus

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BasidiaBasidia

SporangiaSporangia

Parasitic Fungi

Cause Disease DirectlyCause Disease Directly Parasitic Fungi Actual fungal growth in

organism Cause Disease IndirectlyCause Disease Indirectly

Allergic reactions Toxin ingestionToxin ingestion

Exhibit DimorphismExhibit Dimorphism Mould form (mycelial, filamentous) Yeast form (or spherule form) Change due to temperature, nutrients, CO2

levels

Major Fila of Fungi

Chytridiomycota— sexual and asexual spores motile, with posterior flagella

Zygomycota— sexual spores are thick walled resting spores called zygospores

Ascomycota—spores borne internally in a sac called an ascus

Basidiomycota—spores borne externally on a club-shaped structure called a basidium

“deuteromycetes” or Fungi Imperfecti, have no known sexual state in their life cycle.

MYCOSES

Mycose:Disease caused by a fungus

Superficial Cutaneous Subcutaneous Systemic Opportunistic

Superficial fungal infection

Skin infection Limited to stratum corneum Do not penetrate deeper tissues No inflammationSuperficial mycoses *Black piedra *White piedra *Pityriasis versicolor *Tinea nigra

Black piedraWhite piedra

Cutaneous mycoses

Dermatophytoses Clinical condition caused by

fungal infection of the skin in humans

Dermatomycoses Skin disease caused by a fungus

Subcutaneous mycosesSubcutaneous mycoses

Caused by trauma and introduction of the fungus and bacteria

Chromoblastomycosis Phaeohyphomicosis Mycetoma Sporothricosis

Mycetoma

Systemic mycosisSystemic mycosis

Histoplasmosis Coccidiomycosis Blastomycosis Cryptococcosis

Histoplasmosis

Opportunistic mycosesOpportunistic mycoses

Candidiasis Aspergillosis Mucormycosis Pycomycosis

candidiasis