Fungi are eukaryotic organisms that have true nuclei surrounded by nuclear membranes and rigid cell walls composed of chitin and other polysaccharides. They can grow in the form of molds or yeasts. Molds grow through the development of branching filamentous structures called hyphae that make up the mycelium, while yeasts grow primarily by budding and may form chains or clusters of cells. Fungi live in diverse habitats around the world as saprophytes that decompose organic matter or as parasites of plants, animals, and insects. Many fungi are used commercially in food production, such as Saccharomyces in brewing and baking or Penicillium roqueforti in cheesemaking.

1. Morphology of fungi

2. Fungi are eukaryote
they have true nuclei surrounded
by nuclear membrane
and have rigid cell wall like plant
they are larger than procaryote
with typically filamentous growth
the majority are aerobes
they require oxygen at some stage of their growth

3. Fungi live every where and have very diverse habitat most fungi are
saprophytes and found on vegetation
decomposing organic matter soil and waters
some are parasite on plants animals and insects

4. Many fungi can produce mycotoxin in food and in animal feeds
which can cause toxicosis
some used in food industries
saccharomyces used in alcoholic drink yoghurt bread penccillium
requeforti which is used in producing cheese
many used in vitamins production
penicillium chryogenium used in producing pencillin G

5. some are obligate aerobes
others facultative aerobes
and can ferment sugar and grow anaerobically
fungi are organotrophs
require organic source of carbon
fungi are slow grower in comparison
to many bacteria and resistant to antibiotics

6. Morphology of fungi
fungi grow in two morphologic forms
yeasts or molds

7. Yeast form
yeasts grow mainly by budding
producing
spherical to ellipsoidal cells
3-15 micron in diameter
either single or attached to each other forming pseudo hyphae
they never produce aerial hyphae
this is reflected on morphology of colonies on agar media
which resemble bacterial growth

8. the colony are
pasty opaque
and may be white creamy yellowish red
or even black in color
the yeast color generally attain a diameter of
0.5- -3 mm within 3 days

9. the mould form
the mould grow through the development of tube like extension
forming what is known as hypha
the mass of interwind hyphae is called mycelium
the hypha may be divided into
individual cells by septa which is cross walled that present one or
two pores

10. The hypha may present no septa
and remain as continuous tube
apportion of mycelium grows
into the medium called vegetative mycelium
visible part grow above
the medium called aerial mycelium

11. The aerial mycelium gives the colony fluffy
appearance and bear the reproductive
structures which give the colony its color

12. The mold colony varies in its appearance size from few mm to few
cm so the single colony may cover all the surface of the plate
it may be Glabrous
verrucose
fluffy
surface texture may be velvety cottony powdery may assume any
color or grade of color known in nature

13. Some molds have the character of dimorphism dimorphic moulds
as they can grow also in a yeast form
it takes place in tissue when the mold invade tissues
it change to yeast form or In lab
when the colony plated on enriched media
such as brain heart infusion agar and incubated at 37c

14. The rigid cell wall of fungi consisted of
chitinous microfibrils embedded in a matrix of
small polysaccharides protein lipids
the major polysaccharide cell wall matrix
consisted of glucan, manans, chitosan and
galactan

15. Yeasts have soluble peptidomanans as
component of their outer cell wall
the outer cell wall of dermatophytes contains
glycopeptides that may evoke both immediate
and delayed hypersensitivity

16. The plasma membrane is similar to the
mammalian plasma membrane
differ it has the non polar ergosterol instead of
cholesterol
as a principal sterol
this is the site of action of antifungal

17. Fungal nuclei are variable in size and shape and numbers
the DNA and associated protein occur as long filaments of
chromatin which condense during nuclear division
the number of chromosomes varies with particular fungus
the fungal cell may contain up to 100 mitochondria