Chapter 6. Fungiwebbuild.knu.ac.kr/~app-mic/resources/lecture... · 2017-11-16 · Chapter 6. Fungi...
Transcript of Chapter 6. Fungiwebbuild.knu.ac.kr/~app-mic/resources/lecture... · 2017-11-16 · Chapter 6. Fungi...
Chapter 6. Fungi
☞ Fungi (균류, not 곰팡이)
- eukaryotic microbes
- several times larger than the bacterial cell
- broad diversity in structure and mode of life
- two types of microbes
-> yeast(진균) : single cell, fermentation ability
-> mold(곰팡이) : filamentous, important decomposer of organic matter
- 100,000 species were identified, 200,000 species are waiting to be discovered
- classified as the kingdom of Fungi by Whittaker system
1. Structure and growth 1) structure
- most species are composed of strands of cells (except yeast)
-> hypha (균사, pl. hyphae) : a single fungal strand
-> mycelium (균사체, pl. mycelia) : collection of hyphae
- nucleated, spore-bearing, no chlorophyll
- cell wall composed of chitin (polymer of NAG)
- septum (격벽) : partitions between cells
-> pores in septum
-> coenocytic (다핵체형) : no septum
Chapter 6. Fungi
Germinating spore
2) Nutrition
- heterotrophic -> excrete hydrolytic enzymes
-> cellulase, ligninase
- store carbohydrates as glycogen (vs starch by plants)
- saprobes (부생성, most fungal species live on dead organic matter)
-> some are parasites (live on living things)
- many species are acidophilic (btwn pH 5.0 and 6.0)
-> easy contamination in acidic foods (cheese, yogurt)
Chapter 6. Fungi
Blue cheese Yogurt
3) Reproduction
- most known fungi reproduce by both sexual and asexual methods
- reproduction depends on production of spore
-> arthrospore (분절포자) : hypha undergoes fragmentation
-> chlamydospore (후막포자) : thick-walled spore
-> thru the process of mitosis : yield genetically identical daughter cells - spore
-> sporangium (포자낭), conidiophore (분생자병)
Chapter 6. Fungi
☞ sexual reproduction
- all the mycelium have haploid nuclei
- involves cell fusion and spore formation
- gametes (배우자, haploid)
fusion of cells
zygote (접합자, diploid)
meiosis(감수분열)
form spores
Chapter 6. Fungi
2. Divisions of Fungi- four divisions
1. Zygomycota (접합균류문) :
-> fungi form sexually produced zygospore
2. Ascomycota (자낭균류문) :
-> form sexually produced ascospore within saclike body
3. Basidiomycota (담자균류) :
-> form sexually produced basidiospore on supportive structure
4. Deuteromycota (불완전균류) :
-> currently no sexually produced spores are recognized
Chapter 6. Fungi
1) Zygomycota
- fungi are called zygomycetes (접합균류)
- produce zygospore (접합포자, diploid cell) from fusion of two sexually opposite cells
- ex) Rhizopus stolonifer : 빵에 피는 일반적 검은 곰팡이
Chapter 6. Fungi
2) Ascomycota
- fungi are called Ascomycetes (자낭균류, sac fungi)
- form tiny spore-containing sac (ascus, 자낭)
- form ascospore (haploid) :
=> haploid nuclei -> fuse -> diploid cell -> meiosis -> eight haploid ascospore
- ex) Penicillium, Aspergillus
Chapter 6. Fungi
자낭균류
3) Basidiomycota
- fungi are called Basidiomycetes (담자균류, club fungi)
- well known as mushroom (basidiocarp, 담자과 = spore producing body of fungus)
- have long dikaryotic stage (two haploid nuclei)
-> basidiocarp = dense mass of dikaryotic hyphae
Chapter 6. Fungi
담자균류 생활사
3. Other fungi1) Yeast (beneficial or harmful)
- Saccharomyces : nonpathogenic genus of yeast
-> S. cerevisiae : 제빵, S. ellipsoideus : 알콜발효
- Candida albicans : infectious yeast, dimorphic life (oval yeast or filamentous hypha)
- reproduction by budding (동종이형)
Chapter 6. Fungi
S. ellipsoideus (a) and S. cerevisiae (b)Dimorphic C. albicans
2) Lichens (지의류)
- organisms resulting from association btwn a fungus and photosynthetic partner
- cyanobacterium or unicellular green algae
- lichen mass = 90% fungal + 10% photosynthetic partner
- can grow in harsh environments (desert, arctic zone, rocky area)
- photosynthetic partner -> provide sugars and carbohydrtaes
- fungal partner -> provide nutrients and protection from harsh environments
Chapter 6. Fungi
3) Mycorrhizae (균근)
- symbiotic mutualistic association btwn fungi and vascular plants
- fungus -> supply more nutrient(phosphorous)
- plants -> provide photosynthetic products
crusty lichen cross section of a lichen