30. General characterisation of fungi, their morphology, culture, replication, resistance, groups.

Question 1

Fungi Habitat?

Answer 1

widely distributed
environment:
soil
water
air
decaying material
animal, human:
skin
mucous membranes
gut

Question 2

Morphology/Resistance?

Answer 2

uni- or multicellular, 3-100 mm,
branching
cell structure:
cell wall (chitin,
hemicellulose,
mucopolysaccharid,
protein, lipid – impart
rigidity and osmotic
stability),
septa (cross-walls): are
often present in hyphae
(central pore),
cytoplasma membrane
(ergosterol),
nuclear membrane,
nucleus,
nucleolus,
ribosomes,
endoplasmatic reticulum,
mitochondria,
lomasoma.
Moulds: grow as branching
filaments called hyphae (2-10
μm in diam.)
Yeasts: oval cells (3-5 μm)
Dimorphic: occur in both forms
(temp.!)
R:
sexual spores > asexual spores
>vegetative parts
good resistance
dehydration, years
high osmotic pressure
low pH

Question 3

Staining?

Answer 3

unstained
staining
simple staining
(methylene blue)
Gram-staining (yeast)
ĺGr +
PAS (periodic acid –
Schiff reaction) – in tissue
sections
hair or skin scrapings:
clearing the specimen
with 10% KOH
Reproduction
reproduction with sexual
and asexual spores
Sexual:
zygospora (two hypha
cells)
ascospora (ascus)
basidiospora (on club
shaped structures:
basidium)
Asexual:
two main types of spores:
Conidia are forms on
conidiophores.
Sporangiospores are
formed within
sporangium.

Question 4

Culture?

Answer 4

Question 5

Biochemistry/ Antigens

Answer 5

Position and characteristics of fungi
eukaryotic
non photosynthetic
produce exoenzymes and obtain nutrients by absorption,
active metabolism (deterioration of food)
degradation of organic materials, recycling
biochemical examinations: yeasts, dermatophytes
mycotoxin production
production of antibiotics
A:
complex
serological tests in systemic diseases (yeasts)
Identification
morphology (macroscopic- microscopic)
biochemical features (yeasts)
serological examinations
on the basis of genotype (PCR)
Taxonomy
Phylogenetic (Genotypic) classification (5 phyla)
Based on the 18S and the 26S ribosomal RNA gene
5 phyla:
Microspora
Ascomycota
Basidiomycota
Blastocladiomycota
Glomeromycota – major ecological importance,
symbionts with plant roots