Photo’s courtesy of : Sylvia T.

Pratiwi
Differences between Bacteria and Fungi
Characteristic Bacteria Fungi
Size Smaller Larger
Cell Wall Peptidoglycan Chitin
Classification Prokaryot Eukaryot
Type of cells Unicellular Unicellular
multicellular
Cell membrane Sterol absent, except in Mycoplasma Sterol present
Spores Survival reproduction
Reproduction Asexual Sexual (mitotic)
Asexual (meiotic)
Motility Variable Non-motile
Metabolism Heterotrophis, chemoautotrophic, Limited to Heterotrophs /
photoautotrophic, aerobic, facultatively chemoheterotrophs; aerobic/facultative
anaerobic anaerobic
 Fungi are eukaryotic protista; differ from bacteria and other prokaryotes.
1. Cell walls containing chitin (rigidity & support), mannan & other polysaccharides
2. Cytoplasmic membrane contains ergosterols
3. Possess true nuclei with nuclear membrane & paired chromosomes.
4. Divide asexually, sexually or by both
5. Unicellular or multicellular
6. heterotrophic organism devoid of chlorophyll that obtains its nutrients by absorption
7. reproduces by spores.
 Simplest fungus :- Unicellular budding yeast

 Hyphae :- Elongation of apical cell produces a tubular, thread

like structure called hypha

 Mycelium :- Tangled mass of hyphae is called mycelium. Fungi

producing mycelia are called molds or filamentous fungi.

 Hyphae may be septate or non-septate

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1. Yeasts
2. Molds
3. Dimorphic Fungi

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 On culture - produce smooth, creamy colonies
e. g Cryptococcus neoformans (capsulated yeast)

Unicellular fungi, nonfilamentous, typically oval or spherical cells. Reproduce by

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.
 Form true mycelia & reproduce by formation
of different types of spores.

 Vegetative/ aerial hyphae

e.g. Rhizopus, mucor

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Molds and Fleshy Fungi

Multicellular, filamentous fungi.

Identified by physical appearance, colony characteristics, and reproductive spores.
 Thallus : Body of a mold or fleshy fungus. Consists of many hyphae.
 Hyphae (Sing : Hypha) : Long filaments of cells joined together.
Hyphae grow by elongating at the tips.
Each part of a hypha is capable of growth.
Vegetative Hypha : Portion that obtains nutrients.
Reproductive or Aerial Hypha : Portion connected with reproduction.
 Mycelium : Large, visible, filamentous mass made up of many hyphae.
 Except for yeast, hyphae are organised
around and within food source:
 Composed of tubular walls containing
chitin
 Provide enormous surface area: 10cm2
of soil may contain 1km of hyphae with
314cm2 surface area

 Hyphae of septate fungi are divided into

cells by crosswalls called septa

 Hyphae of aseptate fungi lack cross walls

(coenocytic)

 Parasitic fungi have modified hyphae

called haustoria, which penetrate the host
tissue but remain outside cell membrane
 Grow partly as yeasts and partly as elongated cells resembling hyphae which are called
pseudohyphae. e.g. Candida albicans
 Occur in 2 forms
Molds (Filaments) – 25C (soil)
Yeasts – 37C (in host tissue)

Most fungi causing systemic infections are dimorphic:

 Histoplasma capsulatum
 Blastomyces dermatidis
 Paracoccidioides brasiliensis
 Coccidioides immitis
 Penicillium marneffei
 Sporothrix schenkii
 Candida albicans

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 The morphology of multicellular fungi
enhances their ability to absorb nutrients

 Fungi consist of mycelia, networks of

branched hyphae adapted for absorption

 Most fungi have cell walls made of chitin

 Some fungi have hyphae divided into cells

by septa, with pores allowing cell-to-cell
movement

 Coenocytic fungi lack septa

 Some unique fungi have specialized

hyphae that allow them to penetrate the
tissues of their host
 Hyphae 25 µm
Nematode

Hyphae adapted for trapping and killing prey

Plant
Fungal hypha cell
wall

Plant cell

Plant cell
Haustorium plasma
Haustoria membrane
 Structural components:
 chitin microfibrils [ß(1-4)-linked polymer of N-
acetylglucosamine]
 ß-linked glucans
 Gel-like components:
 Mannoproteins (form matrix throughout wall)
 Antigenic glycoproteins, agglutinans, adhesions—
on cell wall surface
 Melanins—dark brown to black pigments (confer
resistance to enzyme lysis, confer mechanical
strength and protect cells from UV light, solar
radiation and desiccation)
 Plasma membrane—semi-permeable
 Ergosterol is the major lipid component of the
underlying plasma
 Division Fibrous Gel-like Polymer
Basidiomycota Chitin Xylomannoproteins
β -(1-3), β-(1-6) Glucan α (1-3) Glucan
Ascomycota chitin Galactomannoproteins
β -(1-3), β-(1-6) Glucan α (1-3) Glucan
Zygomycota Chitin Polyglucuronic acid
Chitosan Glucuronomannoproteins
Polyphosphate
Chytridiomycota Chitin Glucan
Glucan

Taken from : http://bugs.bio.usyd.edu.au/learning/resources/Mycology/StructureFunction/wallComposition.shtml

 Sexual (by meiosis) - formation of zygospores, ascospores or basidiospores

 Asexual reproduction (by mitosis) – budding or fission

 Asexual spores are formed on or in specialized structures.
 Vary in size, shape & color, but these characteristics are constant for a particular species.

 Spores are the agent of dispersal responsible for geographic distribution of fungi:
 Carried by wind or water
 Germinate in moist places with appropriate substrata
Asexual
Sexual
 Fungal nuclei are normally haploid, with the exception of transient diploid stages formed
during the sexual life cycles
 Sexual reproduction requires the fusion of hyphae from different mating types
 Fungi use sexual signaling molecules called pheromones to communicate their mating type

 Plasmogamy is the union of cytoplasm from two parent mycelia

 In most fungi, the haploid nuclei from each parent do not fuse right away; they coexist in the
mycelium, called a heterokaryon
 In some fungi, the haploid nuclei pair off two to a cell; such a mycelium is said to be dikaryotic

 Hours, days, or even centuries may pass before the occurrence of karyogamy, nuclear fusion
 During karyogamy, the haploid nuclei fuse, producing diploid cells
 The diploid phase is short-lived and undergoes meiosis, producing haploid spores
 The paired processes of karyogamy and meiosis produce genetic variation
 In addition to sexual reproduction, many fungi can reproduce asexually
 Molds produce haploid spores by mitosis and form visible mycelia
 Other fungi that can reproduce asexually are yeasts, which are single cells
 Instead of producing spores, yeasts reproduce asexually by simple cell division and the
pinching of “bud cells” from a parent cell
10 m

Parent cell

Bud
 A sporangium is a sac or case
in which spores are produced.

 This is a Rhizopus sporangium.

 Zygote Arbuscular Sac Club
 Fungi have radiated into a Chytrids
fungi mycorrhizal fungi fungi
diverse set of lineages fungi

 The phyla of fungi are

identified by the shape and
presence of their sporangium

Glomeromycota

Basidiomycota
Ascomycota
Zygomycota
Chytridiomycota
Five Phyla of Fungi
 The most primitive fungi Hyphae 25 m

 Fungi classified in the phylum

Chytridiomycota, or chytrids
 Are found in freshwater and terrestrial
habitats, but mainly aquatic
 Can be saprobic or parasitic
 Chytrids are unique among fungi
 In having flagellated spores, called
Flagellum
zoospores
4 m
 Lower fungi;
 Broad, nonseptate hyphae

 Asexual spores - Sporangiospores: present within a swollen sac-

like structure called Sporangium
 They include fast-growing molds, parasites, and commensal
symbionts

 The zygomycetes are named for their sexually produced

zygosporangia

 Zygosporangia resistant to freezing and drying

 Are capable of persisting through unfavorable conditions
 Can undergo meiosis when conditions improve

 The life cycle of black bread mold (Rhizopus stolonifer) is fairly

typical of the phylum
Rhizoids = root-like hyphae
The Rhizoids meet underground and mating occurs between hyphae of different molds (SEXUAL
REPRODUCTION)
 Some zygomycetes, such as Pilobolus can actually “aim” their sporangia toward
conditions associated with good food sources

This decomposer
of animal dung
bends toward
bright light and
shoots its
sporangia up to 2
meters

0.5 mm
 Fungi in the phylum Ascomycota

 Include unicellular yeasts and complex

multicellular (filamentous) cup fungi
 Are found in a variety of marine,
freshwater, and terrestrial habitats

Morchella esculenta
 Sexual spores called ascospores are
present within a sac like structure called
Ascus.

 Several asci may be seen within a fruiting

body as seen in Penicillium, Aspergillus

 Each ascus has 4 to 8 ascospores

In sexual reproduction, haploid mycelia of
opposite mating strains fuse

Asexual spores are called conidia borne on

conidiophore

Hyphae are septate

 It is characterized by basidia – club shaped
hyphae that produce basidiospores during
sexual reproduction.
 Important decomposers of wood / plant
material
 Include:
 Mycorrhiza-forming mutualists
 Mushroom-forming fungi
 Plant parasites e.g. rusts and smuts
 Characterised by dikaryotic mycelium that
reproduces sexually via basidiocarps
 PHYLUM DEUTEROMYCOTA
No Longer Exist!!

• 22,000 species.
• No known sexual stage.
• Saprophytic, parasitic and predatory.
• Many produce conidia.
• Most classified as Ascomycota.
• Fusarium wilt of tomato, potato and cotton.
• Athletes foot, ring worm
 Penicillin

Woops…
now Ascomycota
 Candida albicans
“yeast infection”
Kingdom Fungi

About 100,000 species

Uses:
• medicine
• Food

Ecological value:
• major decomposers
• symbiotic relationships (N2 fixers)

Problems:
• some strains are deadly
• athletes foot
• destroy library books
• destroy crops
 Fungi produce many products used in the medical field such as penicillin, cephalosporin
antibotics, cortisone
 Fungi are used in genetic engineering – vaccine for hepatitis B was developed using the yeast
plasmid as the vector.
 Yeast is used to make ethanol.
 Yeast are known for making breads rise.
 Mushrooms, morels and truffles are widely consumed by humans.
Source of food e.g. Antibiotic production e.g.
mushrooms Penicillin from Penicillium
notatum

Fermentation - Production of alcohol,

bread, cheese e.g.
Sacchromyces spps

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Ergot from Claviceps purpurea, Vaccines for Hepatitis B –
used to induce uterine Sacchromyces cerevisiae
contractions

44
 Fungi are heterotrophs that acquire nutrients by absorption

 Secrete hydrolytic enzymes and acids to decompose complex molecules into simpler ones that
can be absorbed

 Specialised into three main types:

 Saprobes - absorb nutrients from dead organic material
 Parasitic fungi - absorb nutrients from cells of living hosts; some are pathogenic
 Mutualistic fungi - absorb nutrients from a host, but reciprocate to benefit the host
 Called saprophytes, they act as recyclers of dead organic matter, obtaining food from this
material.

 Hyphal tips release enzymes that eventually decompose and release organic materials into the
surrounding environment.

 Saprophytic fungi appear on dead trees, logs, plant litter such as leaves, and even dead insects
and animals. Examples: "Gem-studded Puffball" (Lycoperdon perlatum) and "Turkey
Tail"(Trametes versicolor).
 Endophyte

Lichen – symbiotic relationship between

algae and fungi
 Some fungi share their digestive services with animals
 These fungi help break down plant material in the guts of cows and other grazing mammals
 Many species of ants use the digestive power of fungi by raising them in “farms”
 About 30% of the 100,000 known species of fungi are parasites, mostly on or in plants.

 Many people have allergies triggered by mold.

 Fungal skin infections – skin, nails and hair
 Ringworm, athlete’s foot

 Internal organs – Histoplasmosis

 Superficial mycoses:
 2 types: surface and cutaneous mycoses
 Skin, hair & nails.
 Mild but chronic disease

 Deep mycoses:
 2 types: subcutaneous & systemic mycoses
 Caused by soil saprophytes
 Infection is accidental
 Range from a symptomatic infection to fatal disease

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 Mainly caused by fungi which are common lab contaminant on culture media
 Aspergillus
 Penicillium
 Mucor
 Rhizopus
 Candida
 Produce serious & fatal infections

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