2. One of the five taxonomic kingdoms
(along with Animalia, Plantae,
Protista and Monera), the Fungi are
a diverse group of heterotrophic
organisms with a rigid cell wall.
The fungi (singular, fungus ) are
eucaryotic spore bearing protists
that lack chlorophyll.
A group of microorganisms that
includes moulds and yeasts.
They are usually found in moist area
or grows in dead decaying ,organic
matter.
3. FEATURES OF FUNGI
Eukaryotic chemoorganotrophic organisms that have no
chlorophyll.
Non vascular organism.
Reproduce by means of spores usually air disseminated.
Both sexual (miotic) and asexual (mitotic) spores may be produced
depends on species and environment.
Typically not motile although few (chytrids)have a motile phase.
Like plants fungi have alternation of generation.
Vegetative body mainly unicellular(yeast) or composed of
microscopic threads called hyphae.
Cell wall similar in structure to plants but differ in chemical
composition, fungi cell walls are composed of chitin. Plant cell are
mainly composed of cellulose.
Fungi are heterotrophs, obtaining their nutrients by absorption.
Store carbohydrate as glycogen.
They are saprophytic ,parasitic organism.
4. FUNGI
MOULD YEAST LIKE FUNGI
YEAST DIMORPHIC They grow partly
Filamentous and Unicellular They exist in two As yeasts and
mycellial Spread rapidly forms, both partly as elongated
Form spores and through host body Yeast and
spread by spores
cells resembling
Yeast moulds hyphae(psudomyce
Only locally invasive
saccharomyces Taphrina lium)
Ring worm fungi
Candida albinos
5. HOW DO WE CLASSIFY ?
1.Zygomycota:. Members of the division Zygomycota are known as zygomycetes. Zygomycetes produce
sexual spores known as zygospores as well as asexual sporangiospores. mold Rhizopus stolonifer
2.Ascomycota: These organisms form their sexual spores within a sac called an ascus. Therefore, they
are called sac fungi. yeast Saccharomyces.
3. Basidiomycota: After the sexual cells have united, they undergo division and produce a clubshaped
structure called a basidium. Mushrooms
4.Deuteromycota: These fungi lack a known sexual cycle of reproduction and are said to be
“imperfect.” ringworm.
5.Mycophycota (lichens): These fungi depends on algae or cyanobacteria for food.
crustose lichens
6. MOULD VS YEAST
POINT OF MOULD YEAST
DISTINCTION
STRUCTURE Multicellular with tubular , Mostly unicellular and existing
filamentous hyphae(branches) individually or with buds
growing on them.
PREDOMINANCE OF Any organic environment Mostly occur naturally in
OCCURRENCE having a moist/humid oceans.
atmosphere and not exposed
to harsh weather conditions
METHOD OF Production of sexual or Budding or binary fission.
REPRODUCTION asexual , airborne spores.
APPEARANCE Threadlike, come in a wide Round or oval-shaped, dull
variety of colors and hues. colored and mostly
monochromatic.
7. HOW THEY REPRODUCE?
SEXUALLY-
Two different cells ,one with ‘+’
strain (male) another is ‘-’ strain
(female) comes closer and fuse
together. First cytoplasm then
nuclei fuse together.
ASEXUALLY-
Production of various types of
spores
Fragmentation – hyphae dry out
and shatter releasing individual
cells that act like spores.
Budding – small offspring
A-D-budding ,F -H-fission , shown
in the figure.
8. MYCOSES
INFECTIONS CAUSED BY FUNGI
SUPERFICIAL MYCOSES -AFFECTS SYSTEMIC MYCOSES-AFFECTS DEEP
OUTERMOST LAYERS .e .g ATHLETE’S FOOT, ORGANS. e.g
TINEA VERSICOLOR CANDIDIASIS,ASPERGILLOSIS
CUTANEOUS MYCOSES –affects DUE TO PRIMARY PATHOGENS-
deeper into epidermis,also includes primarily originate from lungs then
hair, nail spread to other organ system.
SUBCUTANEOUS MYCOSES-affects DUE TO OPPORTUNISTIC
subcutaneous tissues,muscle and PATHOGENS-affects those with
fascia. immune deficiency
9. ANTIFUNGAL DRUGS
ANTIFUNGAL MECHANISM OF ACTION EXAMPLES
AGENTS
POLYENE These antibiotics bind with sterols in the fungal cell Nystatin(cutaneous
ANTIBIOTICS membrane, principally ergosterol,and causes the cell's candida)(T)
contents to leak out and the cell dies.So animal cells Amphotericin B (may be
become less susceptible. administered
liposomally) (Oral
candidiasis)(0)
IMIDAZOLE AND These antifungal drugs inhibit the enzyme cytochrome IMIDAZOLE:
TRIAZOLE P450 14α-demethylase. This enzyme converts KETOCONAZOLE(Athlete’s
lanosterol to ergosterol, and is required in fungal cell foot, ringworm) (T)
membrane synthesis. These drugs also block steroid TRIAZOLE:Fluconazole
synthesis in humans.
ALLYLAMINES Inhibits the enzyme squalene epoxidase, another Naftifine (Tinea
enzyme required for ergosterol synthesis. corporis)(T)
ECHINOCANDIN Inhibits the synthesis of glucan in the cell wall, Micafungin (Candida
probably via the enzyme 1,3-β glucan synthase. peritinotis) (IV)
