General characteristics and life cycle of fungi

1. GENERAL CHARACTERISTICS
AND LIFE CYCLE OF FUNGI
PRESENTER:
RITWICK.R.SARMA
12480
M.Sc. BIOSCIENCE
YENEPOYA RESEARCH
CENTRE
Friday seminar : 23rd August

2. CONTENTS
• What is mycology?
• General characteristics of Fungi
• Chytridiomycota
• Zygomycota
• Ascomycota(sac fungi)
• Basidiomycota
• Other fungi
• Importance of fungi

3. WHAT IS MYCOLOGY?
• The term “mycology” is derived from Greek word
meaning “mykes” meaning mushroom.
• Therefore mycology is the study of fungi, including
their genetic and biological properties, their
taxonomy, uses as well as dangers.

4. GENERAL CHARACTERISTICS OF
FUNGI
• Fungi are eukaryotic in nature.
• Nearly all fungi are multicellular (yeasts are
unicellular)
• Distinguished from other kingdoms by:
o Nutrition
o Structural organisation
o Growth
o Reproduction

5. Absorptive nutrition enables fungi to
live as decomposers and symbionts
• 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:
o Saprobes - absorb nutrients from dead organic material
o Parasitic fungi - absorb nutrients from cells of living hosts;
some are pathogenic
o Mutualistic fungi - absorb nutrients from a host, but
reciprocate to benefit the host

6. Extensive surface area and rapid growth
adapt fungi for absorptive nutrition
Basic structural unit of fungal
vegetative body (mycelium) is the
hypha
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.
Source: pinterest.com

7. Fungal hyphae may be septate or aseptate
• 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.
Source: pinterest.com

8. Fungi reproduce by releasing
spores that are produced either
sexually or asexually
• Unicellular , haploid and various shapes & sizes
• Produced sexually (by meiosis) or asexually (by mitosis)
o In favourable conditions, fungi produces spores asexually
o Sexual reproduction only occurs as a contingency.
• Geographic distribution of fungi:
o Carried by wind or water
o Germinate in moist places with appropriate substrata

9. Generalised life cycle of
fungi
Sexual
Asexual
Source: pinterest.com

10. Phylogeny of fungi
Source: courses.lumenlearning.com

11. Division
Chytridiomyciota
• Originally placed in
Kingdom Protista
• Share many
characteristics with
fungi:
o Absorptive nutrition
o Chitin cell walls
o Hyphae
o Enzymes /
metabolism
• Earliest fungi: evolved
from protists and
retained flagella.
Source: pinterest.com

12. Division Zygomycota
• Characterised by
zygosporangia.
• Mostly terrestrial
• Some form
mycorrhizae.
• Hyphae are
coenocytic.
Source: pinterest.com

13. Source: https://www.youtube.com/watch?v
Fig : Bread mould

14. Life cycle of the zygomycete Rhizopus
stolonifer, a common bread mould
Source: pinterest.com

15. Division Ascomycota: sac
fungi
• Include unicellular yeasts and
complex multicellular cup fungi
• Hyphae are septate
• In asexual reproduction, tips of
specialised hyphae form conidia
- chains of haploid asexual
spores
• In sexual reproduction, haploid
mycelia of opposite mating
strains fuse
Source: pinterest.com

16. Life cycle of an
ascomycete
ASEXUAL
SEXUAL
MITOSIS
Source: pinterest.com

17. Division Basidiomycota:
club fungi
• Named after transient diploid
stage: basidium
• Important decomposers of
wood / plant material
• Include:
o Mycorrhiza-forming mutualists
o Mushroom-forming fungi
o Plant parasites e.g. rusts and smuts
• Characterised by dikaryotic
mycelium that reproduces
sexually via basidiocarps
Source: pinterest.com

18. Life cycle of a Basidiomycete
Source: pinterest.com

19. Metabolites found in medicinal mushrooms and
their therapeutic potential against cancer[1]
• Species: Inonotus obliquus
• Compound : 3,4-dihydroxybenzalacetone
• TARGET/MECHANISM OF ACTION: NF-κB
inhibition-mediated apoptosis, suppression of
invasion
• Cancer types affected: Gastric, liver, colon cancer
• Experimental models: Cell lines
[2]

20. Photo source:https://www.brmi.online/single-post/2018/10/08/Inonotus-
obliquus
Inonotus obliquus 3,4-dihydroxybenzalacetone
https://pubchem.ncbi.nlm.nih.gov/compound/2762430#sectio
n=2D-Structure

21. Some mutualistic fungi
LICHENS MYCORRHIZA
Source: www.powerslide.net / gardenmyth.com

22. IMPORTANCE OF FUNGI
 BENIFICIAL ROLE –
•Importanat agents for bio degradation and
biodeterioration.
• Use in industrial fermentation process
Example: Penicillium notatum , Saccharomyces cerevisiae
 HARMFUL ROLE-
• Destruction of food, lumber , paper and cloth
• Animal and human diseases,including allergies, ringworm
• Plant diseases.

23. References
1. Sung B, Pandey MK, Nakajima Y, Nishida H, Konishi T, Chaturvedi MM,
Aggarwal BB. Identification of a novel blocker of IkappaBalpha kinase
activation that enhances apoptosis and inhibits proliferation and invasion by
suppressing nuclear factor-kappaB. Mol Cancer Ther. 2008;7:191–201. doi:
10.1158/1535-7163.MCT-07-0406. [PubMed] [CrossRef] [Google
Scholar] [Ref list]
2. Medicinal mushrooms as an attractive new source of natural compounds for
future cancer therapy Artem Blagodatski,1,2,* Margarita
Yatsunskaya,3,* Valeriia Mikhailova,1 Vladlena Tiasto,1 Alexander
Kagansky,1and Vladimir L. Katanaev1,2 PMCID: PMC6044372
PMID: 30018750 [PubMed] doi: 10.18632/oncotarget.25660
• https://mycology.adelaide.edu.au/
• https://highveld.com/microbiology/what-are-fungi.html
• www.ucmp.berkeley.edu/fungi/fungi.html
• https://www.ncbi.nlm.nih.gov/pubmed/

24. THANK YOU