Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
prominent members of ecosystems
useful as model systems and industry
some are major human pathogens
two groups
protists
fungi
2
100,000 species divided into 2 groups:
Macroscopic fungi (mushrooms, puffballs, gill fungi)
Microscopic fungi (molds, yeasts)
Majority are unicellular or colonial; a few have cellular specialization
4
Exist in two morphologies:
Yeast – round ovoid shape, asexual reproduction
Hyphae – long filamentous fungi or molds
Some exist in either form – dimorphic – characteristic of some pathogenic molds
5
All are heterotrophic
Majority are harmless saprobes living off dead plants and animals
Some are parasites, living on the tissues of other organisms, but none are obligate Mycoses – fungal infections
Growth temperature 20o-40oC
Extremely widespread distribution in many habitats
8
Most grow in loose associations or colonies
Yeast – soft, uniform texture and appearance
Filamentous fungi – mass of hyphae called mycelium; cottony, hairy, or velvety texture
Hyphae may be divided by cross walls – septate
Vegetative hyphae – digest and absorb nutrients
Reproductive hyphae – produce spores for reproduction
10
Isolation on specific media
Macroscopic and microscopic observation of: Asexual spore-forming structures and spores
Hyphal type
Colony texture and pigmentation
Physiological characteristics
Genetic makeup
12
Primarily through spores formed on reproductive hyphae
Asexual reproduction – spores are formed through budding or mitosis; conidia or sporangiospores
13
Sexual reproduction – spores are formed following fusion of two different strains and formation of sexual structure
Zygospores, ascospores, and basidiospores
Sexual spores and spore-forming structures are one basis for classification
15
Kingdom Eumycota is subdivided into several phyla based upon the type of sexual reproduction:
1. Zygomycota – zygospores; sporangiospores and some conidia
2. Ascomycota – ascospores; conidia
3. Basidiomycota – basidiospores; conidia
4. Chytridomycota – flagellated spores
5. Fungi that produce only Asexual Spores (Imperfect)
16
Adverse impact Mycoses, allergies, toxin production
Destruction of crops and food storages
Beneficial impact Decomposers of dead plants and animals
Sources of antibiotics, alcohol, organic acids, vitamins
Used in making foods and in genetic studies
20